Fix chunked_buffer clippy

Still lots of work to do here. Also a lot of copying going on that
should be avoided.

.circleci/config.yml

@@ -1,19 +1,35 @@
 version: 2.1
 
-orbs:
-  python: circleci/python@1.4.0
-
 executors:
   zenith-build-executor:
     resource_class: xlarge
     docker:
-      - image: cimg/rust:1.52.1
+      - image: cimg/rust:1.55.0
+  zenith-python-executor:
+    docker:
+      - image: cimg/python:3.7.10  # Oldest available 3.7 with Ubuntu 20.04 (for GLIBC and Rust) at CirlceCI
 
 jobs:
+  check-codestyle:
+    executor: zenith-build-executor
+    steps:
+      - checkout
+
+      - run:
+          name: rustfmt
+          when: always
+          command: |
+            cargo fmt --all -- --check
 
   # A job to build postgres
   build-postgres:
     executor: zenith-build-executor
+    parameters:
+      build_type:
+        type: enum
+        enum: ["debug", "release"]
+    environment:
+      BUILD_TYPE: << parameters.build_type >>
     steps:
         # Checkout the git repo (circleci doesn't have a flag to enable submodules here)
       - checkout
@@ -29,7 +45,7 @@ jobs:
           name: Restore postgres cache
           keys:
             # Restore ONLY if the rev key matches exactly
-            - v03-postgres-cache-{{ checksum "/tmp/cache-key-postgres" }}
+            - v04-postgres-cache-<< parameters.build_type >>-{{ checksum "/tmp/cache-key-postgres" }}
 
         # FIXME We could cache our own docker container, instead of installing packages every time.
       - run:
@@ -49,12 +65,12 @@ jobs:
             if [ ! -e tmp_install/bin/postgres ]; then
               # "depth 1" saves some time by not cloning the whole repo
               git submodule update --init --depth 1
-              make postgres
+              make postgres -j8
             fi
 
       - save_cache:
           name: Save postgres cache
-          key: v03-postgres-cache-{{ checksum "/tmp/cache-key-postgres" }}
+          key: v04-postgres-cache-<< parameters.build_type >>-{{ checksum "/tmp/cache-key-postgres" }}
           paths:
             - tmp_install
 
@@ -86,7 +102,7 @@ jobs:
           name: Restore postgres cache
           keys:
             # Restore ONLY if the rev key matches exactly
-            - v03-postgres-cache-{{ checksum "/tmp/cache-key-postgres" }}
+            - v04-postgres-cache-<< parameters.build_type >>-{{ checksum "/tmp/cache-key-postgres" }}
 
       - restore_cache:
           name: Restore rust cache
@@ -94,7 +110,7 @@ jobs:
             # Require an exact match. While an out of date cache might speed up the build,
             # there's no way to clean out old packages, so the cache grows every time something
             # changes.
-            - v03-rust-cache-deps-<< parameters.build_type >>-{{ checksum "Cargo.lock" }}
+            - v04-rust-cache-deps-<< parameters.build_type >>-{{ checksum "Cargo.lock" }}
 
         # Build the rust code, including test binaries
       - run:
@@ -112,12 +128,20 @@ jobs:
 
       - save_cache:
           name: Save rust cache
-          key: v03-rust-cache-deps-<< parameters.build_type >>-{{ checksum "Cargo.lock" }}
+          key: v04-rust-cache-deps-<< parameters.build_type >>-{{ checksum "Cargo.lock" }}
           paths:
             - ~/.cargo/registry
             - ~/.cargo/git
             - target
 
+        # Run style checks
+        # has to run separately from cargo fmt section
+        # since needs to run with dependencies
+      - run:
+          name: clippy
+          command: |
+            ./run_clippy.sh
+
         # Run rust unit tests
       - run: cargo test
 
@@ -158,9 +182,27 @@ jobs:
           paths:
             - "*"
 
+  check-python:
+    executor: zenith-python-executor
+    steps:
+      - checkout
+      - run:
+          name: Install deps
+          working_directory: test_runner
+          command: pipenv --python 3.7 install --dev
+      - run:
+          name: Run yapf to ensure code format
+          when: always
+          working_directory: test_runner
+          command: pipenv run yapf --recursive --diff .
+      - run:
+          name: Run mypy to check types
+          when: always
+          working_directory: test_runner
+          command: pipenv run mypy .
+
   run-pytest:
-    #description: "Run pytest"
-    executor: python/default
+    executor: zenith-python-executor
     parameters:
       # pytest args to specify the tests to run.
       #
@@ -183,6 +225,9 @@ jobs:
       needs_postgres_source:
         type: boolean
         default: false
+      run_in_parallel:
+        type: boolean
+        default: true
     steps:
       - attach_workspace:
           at: /tmp/zenith
@@ -192,14 +237,15 @@ jobs:
           steps:
             - run: git submodule update --init --depth 1
       - run:
-          name: Install pipenv & deps
+          name: Install deps
           working_directory: test_runner
-          command: |
-            pip install pipenv
-            pipenv install
+          command: pipenv --python 3.7 install
       - run:
           name: Run pytest
           working_directory: test_runner
+          # pytest doesn't output test logs in real time, so CI job may fail
+          # with `Too long with no output` error, if a test is running for a long time.
+          no_output_timeout: 20m
           environment:
             - ZENITH_BIN: /tmp/zenith/bin
             - POSTGRES_DISTRIB_DIR: /tmp/zenith/pg_install
@@ -211,16 +257,20 @@ jobs:
               echo "test_selection must be set"
               exit 1
             fi
+            if << parameters.run_in_parallel >>; then
+              EXTRA_PARAMS="-n4 $EXTRA_PARAMS"
+            fi;
             # Run the tests.
             #
             # The junit.xml file allows CircleCI to display more fine-grained test information
             # in its "Tests" tab in the results page.
-            # -s prevents pytest from capturing output, which helps to see
-            # what's going on if the test hangs
             # --verbose prints name of each test (helpful when there are
             # multiple tests in one file)
             # -rA prints summary in the end
-            pipenv run pytest --junitxml=$TEST_OUTPUT/junit.xml --tb=short -s --verbose -rA $TEST_SELECTION $EXTRA_PARAMS
+            # -n4 uses four processes to run tests via pytest-xdist
+            # -s is not used to prevent pytest from capturing output, because tests are running
+            # in parallel and logs are mixed between different tests
+            pipenv run pytest --junitxml=$TEST_OUTPUT/junit.xml --tb=short --verbose -m "not remote_cluster" -rA $TEST_SELECTION $EXTRA_PARAMS
       - run:
           # CircleCI artifacts are preserved one file at a time, so skipping
           # this step isn't a good idea. If you want to extract the
@@ -229,7 +279,7 @@ jobs:
           when: always
           command: |
             du -sh /tmp/test_output/*
-            find /tmp/test_output -type f ! -name "pg.log" ! -name "pageserver.log" ! -name "wal_acceptor.log" ! -name "regression.diffs" -delete
+            find /tmp/test_output -type f ! -name "pg.log" ! -name "pageserver.log" ! -name "safekeeper.log" ! -name "regression.diffs" ! -name "junit.xml" ! -name "*.filediff" ! -name "*.stdout" ! -name "*.stderr" -delete
             du -sh /tmp/test_output/*
       - store_artifacts:
           path: /tmp/test_output
@@ -252,21 +302,71 @@ jobs:
           name: Build and push Docker image
           command: |
             echo $DOCKER_PWD | docker login -u $DOCKER_LOGIN --password-stdin
-            docker build -t zenithdb/zenith:latest . && docker push zenithdb/zenith:latest
+            docker build --build-arg GIT_VERSION=$CIRCLE_SHA1 -t zenithdb/zenith:latest . && docker push zenithdb/zenith:latest
+
+  # Trigger a new remote CI job
+  remote-ci-trigger:
+    docker:
+      - image: cimg/base:2021.04
+    parameters:
+      remote_repo:
+        type: string
+    environment:
+      REMOTE_REPO: << parameters.remote_repo >>
+    steps:
+      - run:
+          name: Set PR's status to pending
+          command: |
+            LOCAL_REPO=$CIRCLE_PROJECT_USERNAME/$CIRCLE_PROJECT_REPONAME
+
+            curl -f -X POST \
+            https://api.github.com/repos/$LOCAL_REPO/statuses/$CIRCLE_SHA1 \
+            -H "Accept: application/vnd.github.v3+json" \
+            --user "$CI_ACCESS_TOKEN" \
+            --data \
+              "{
+                \"state\": \"pending\",
+                \"context\": \"zenith-remote-ci\",
+                \"description\": \"[$REMOTE_REPO] Remote CI job is about to start\"
+              }"
+      - run:
+          name: Request a remote CI test
+          command: |
+            LOCAL_REPO=$CIRCLE_PROJECT_USERNAME/$CIRCLE_PROJECT_REPONAME
+
+            curl -f -X POST \
+            https://api.github.com/repos/$REMOTE_REPO/actions/workflows/testing.yml/dispatches \
+            -H "Accept: application/vnd.github.v3+json" \
+            --user "$CI_ACCESS_TOKEN" \
+            --data \
+              "{
+                \"ref\": \"main\",
+                \"inputs\": {
+                  \"ci_job_name\": \"zenith-remote-ci\",
+                  \"commit_hash\": \"$CIRCLE_SHA1\",
+                  \"remote_repo\": \"$LOCAL_REPO\"
+                }
+              }"
 
 workflows:
   build_and_test:
     jobs:
-      - build-postgres
+      - check-codestyle
+      - check-python
+      - build-postgres:
+          name: build-postgres-<< matrix.build_type >>
+          matrix:
+            parameters:
+              build_type: ["debug", "release"]
       - build-zenith:
           name: build-zenith-<< matrix.build_type >>
           matrix:
             parameters:
               build_type: ["debug", "release"]
           requires:
-            - build-postgres
+            - build-postgres-<< matrix.build_type >>
       - run-pytest:
-          name: pg_regress tests << matrix.build_type >>
+          name: pg_regress-tests-<< matrix.build_type >>
           matrix:
             parameters:
               build_type: ["debug", "release"]
@@ -275,13 +375,20 @@ workflows:
           requires:
             - build-zenith-<< matrix.build_type >>
       - run-pytest:
-          name: other tests << matrix.build_type >>
+          name: other-tests-<< matrix.build_type >>
           matrix:
             parameters:
               build_type: ["debug", "release"]
           test_selection: batch_others
           requires:
             - build-zenith-<< matrix.build_type >>
+      - run-pytest:
+          name: benchmarks
+          build_type: release
+          test_selection: performance
+          run_in_parallel: false
+          requires:
+            - build-zenith-release
       - docker-image:
           # Context gives an ability to login
           context: Docker Hub
@@ -291,5 +398,16 @@ workflows:
               only:
                 - main
           requires:
-            - pg_regress tests release
-            - other tests release
+            - pg_regress-tests-release
+            - other-tests-release
+      - remote-ci-trigger:
+          # Context passes credentials for gh api
+          context: CI_ACCESS_TOKEN
+          remote_repo: "zenithdb/console"
+          requires:
+            # XXX: Successful build doesn't mean everything is OK, but
+            # the job to be triggered takes so much time to complete (~22 min)
+            # that it's better not to wait for the commented-out steps
+            - build-zenith-debug
+            # - pg_regress-tests-release
+            # - other-tests-release

.dockerignore

@@ -2,12 +2,17 @@
 **/__pycache__
 **/.pytest_cache
 
-/target
-/tmp_check
-/tmp_install
-/tmp_check_cli
-/test_output
-/.vscode
-/.zenith
-/integration_tests/.zenith
-/Dockerfile
+.git
+target
+tmp_check
+tmp_install
+tmp_check_cli
+test_output
+.vscode
+.zenith
+integration_tests/.zenith
+.mypy_cache
+
+Dockerfile
+.dockerignore
+

.github/workflows/benchmarking.yml

@@ -0,0 +1,158 @@
+name: benchmarking
+
+on:
+  # uncomment to run on push for debugging your PR
+  # push:
+  #   branches: [ mybranch ]
+  schedule:
+    # * is a special character in YAML so you have to quote this string
+    #          ┌───────────── minute (0 - 59)
+    #          │ ┌───────────── hour (0 - 23)
+    #          │ │ ┌───────────── day of the month (1 - 31)
+    #          │ │ │ ┌───────────── month (1 - 12 or JAN-DEC)
+    #          │ │ │ │ ┌───────────── day of the week (0 - 6 or SUN-SAT)
+    - cron:  '36 7 * * *' # run once a day, timezone is utc
+
+env:
+  BASE_URL: "https://console.zenith.tech"
+
+jobs:
+  bench:
+    # this workflow runs on self hosteed runner
+    # it's environment is quite different from usual guthub runner
+    # probably the most important difference is that it doesnt start from clean workspace each time
+    # e g if you install system packages they are not cleaned up since you install them directly in host machine
+    # not a container or something
+    # See documentation for more info: https://docs.github.com/en/actions/hosting-your-own-runners/about-self-hosted-runners
+    runs-on: [self-hosted, zenith-benchmarker]
+
+    steps:
+    - name: Checkout zenith repo
+      uses: actions/checkout@v2
+
+    - name: Checkout zenith-perf-data repo
+      uses: actions/checkout@v2
+      with:
+        repository: zenithdb/zenith-perf-data
+        token: ${{ secrets.VIP_VAP_ACCESS_TOKEN }}
+        ref: testing # TODO replace with master once everything is ready
+        path: zenith-perf-data
+
+    # actions/setup-python@v2 is not working correctly on self-hosted runners
+    # see https://github.com/actions/setup-python/issues/162
+    # and probably https://github.com/actions/setup-python/issues/162#issuecomment-865387976 in particular
+    # so the simplest solution to me is to use already installed system python and spin virtualenvs for job runs.
+    # there is Python 3.7.10 already installed on the machine so use it to install pipenv and then use pipenv's virtuealenvs
+    - name: Install pipenv & deps
+      run: |
+        python3 -m pip install --upgrade pipenv wheel
+        # since pip/pipenv caches are reused there shouldn't be any troubles with install every time
+        pipenv install
+
+    - name: Show versions
+      run: |
+        echo Python
+        python3 --version
+        pipenv run python3 --version
+        echo Pipenv
+        pipenv --version
+        echo Pgbench
+        pgbench --version
+
+    # FIXME cluster setup is skipped due to various changes in console API
+    # for now pre created cluster is used. When API gain some stability
+    # after massive changes dynamic cluster setup will be revived.
+    # So use pre created cluster. It needs to be started manually, but stop is automatic after 5 minutes of inactivity
+    - name: Setup cluster
+      env:
+        BENCHMARK_CONSOLE_USER_PASSWORD: "${{ secrets.BENCHMARK_CONSOLE_USER_PASSWORD }}"
+        BENCHMARK_CONSOLE_ACCESS_TOKEN: "${{ secrets.BENCHMARK_CONSOLE_ACCESS_TOKEN }}"
+        # USERNAME: "benchmark"
+      shell: bash
+      run: |
+        set -e
+        # echo "Creating cluster"
+
+        # CLUSTER=$(curl -s --fail --show-error $BASE_URL/api/v1/clusters.json \
+        #     -H 'Content-Type: application/json; charset=utf-8' \
+        #     -H "Authorization: Bearer $BENCHMARK_CONSOLE_ACCESS_TOKEN" \
+        #     --data-binary @- << EOF
+        # {
+        #     "cluster": {
+        #         "name": "default_cluster",
+        #         "region_id": "2",
+        #         "instance_type_id": 7,
+        #         "settings": {}
+        #     },
+        #     "database": {"name": "benchmark"},
+        #     "role": {"name": "$USERNAME", "password": "$BENCHMARK_CONSOLE_USER_PASSWORD"}
+        # }
+        # EOF
+        # )
+
+        # echo "Created cluster"
+
+        echo "Starting cluster"
+        CLUSTER_ID=285
+        CLUSTER=$(curl -s --fail --show-error -X POST $BASE_URL/api/v1/clusters/$CLUSTER_ID/start \
+            -H "Authorization: Bearer $BENCHMARK_CONSOLE_ACCESS_TOKEN")
+        echo $CLUSTER | python -m json.tool
+
+        echo "Waiting for cluster to become ready"
+        sleep 10
+
+        # # note that jq is installed on host system
+        # CLUSTER_ID=$(echo $CLUSTER| jq ".id")
+        echo "CLUSTER_ID=$CLUSTER_ID" >> $GITHUB_ENV
+        # echo "Constructing connstr"
+        # CLUSTER=$(curl -s --fail --show-error -X GET $BASE_URL/api/v1/clusters/$CLUSTER_ID.json \
+        #     -H "Authorization: Bearer $BENCHMARK_CONSOLE_ACCESS_TOKEN")
+
+        # echo $CLUSTER | python -m json.tool
+        # CONNSTR=$(echo $CLUSTER | jq -r ".| \"postgresql://$USERNAME:$BENCHMARK_CONSOLE_USER_PASSWORD@\(.public_ip_address):\(.public_pg_port)/benchmark\"")
+        # echo "BENCHMARK_CONNSTR=$CONNSTR" >> $GITHUB_ENV
+
+    - name: Run benchmark
+      # pgbench is installed system wide from official repo
+      # https://download.postgresql.org/pub/repos/yum/13/redhat/rhel-7-x86_64/
+      # via
+      # sudo tee /etc/yum.repos.d/pgdg.repo<<EOF
+      # [pgdg13]
+      # name=PostgreSQL 13 for RHEL/CentOS 7 - x86_64
+      # baseurl=https://download.postgresql.org/pub/repos/yum/13/redhat/rhel-7-x86_64/
+      # enabled=1
+      # gpgcheck=0
+      # EOF
+      # sudo yum makecache
+      # sudo yum install postgresql13-contrib
+      # actual binaries are located in /usr/pgsql-13/bin/
+      env:
+        PG_BIN: "/usr/pgsql-13/bin/"
+        TEST_PG_BENCH_TRANSACTIONS_MATRIX: "5000,10000,20000"
+        TEST_PG_BENCH_SCALES_MATRIX: "10,15"
+        PLATFORM: "zenith-staging"
+        BENCHMARK_CONSOLE_ACCESS_TOKEN: "${{ secrets.BENCHMARK_CONSOLE_ACCESS_TOKEN }}"
+        BENCHMARK_CONNSTR: "${{ secrets.BENCHMARK_STAGING_CONNSTR }}"
+        REMOTE_ENV: "1" # indicate to test harness that we do not have zenith binaries locally
+      run: |
+        mkdir -p zenith-perf-data/data/staging
+        pipenv run pytest test_runner/performance/ -v -m "remote_cluster" --skip-interfering-proc-check --out-dir zenith-perf-data/data/staging
+
+    - name: Submit result
+      env:
+        VIP_VAP_ACCESS_TOKEN: "${{ secrets.VIP_VAP_ACCESS_TOKEN }}"
+      run: |
+        cd zenith-perf-data
+        git add data
+        git commit --author="vipvap <vipvap@zenith.tech>" -m "add performance test result for $GITHUB_SHA zenith revision"
+        git push https://$VIP_VAP_ACCESS_TOKEN@github.com/zenithdb/zenith-perf-data.git main
+
+    # FIXME see comment above Setup cluster job
+    # change to delete cluster after switching to creating a cluster for every run
+    - name: Stop cluster
+      if: ${{ always() }}
+      env:
+        BENCHMARK_CONSOLE_ACCESS_TOKEN: "${{ secrets.BENCHMARK_CONSOLE_ACCESS_TOKEN }}"
+      run: |
+        curl -s --fail --show-error -X POST $BASE_URL/api/v1/clusters/$CLUSTER_ID/stop \
+            -H "Authorization: Bearer $BENCHMARK_CONSOLE_ACCESS_TOKEN"

.gitmodules

@@ -1,4 +1,4 @@
 [submodule "vendor/postgres"]
 	path = vendor/postgres
-	url = https://github.com/libzenith/postgres
+	url = https://github.com/zenithdb/postgres
 	branch = main

Dockerfile

@@ -10,40 +10,26 @@ FROM zenithdb/build:buster AS pg-build
 WORKDIR /zenith
 COPY ./vendor/postgres vendor/postgres
 COPY ./Makefile Makefile
+ENV BUILD_TYPE release
 RUN make -j $(getconf _NPROCESSORS_ONLN) -s postgres
-
-#
-# Calculate cargo dependencies.
-# This will always run, but only generate recipe.json with list of dependencies without
-# installing them.
-#
-FROM zenithdb/build:buster AS cargo-deps-inspect
-WORKDIR /zenith
-COPY . .
-RUN cargo chef prepare --recipe-path /zenith/recipe.json
-
-#
-# Build cargo dependencies.
-# This temp cantainner should be rebuilt only if recipe.json was changed.
-#
-FROM zenithdb/build:buster AS deps-build
-WORKDIR /zenith
-COPY --from=pg-build /zenith/tmp_install/include/postgresql/server tmp_install/include/postgresql/server
-COPY --from=cargo-deps-inspect /usr/local/cargo/bin/cargo-chef /usr/local/cargo/bin/
-COPY --from=cargo-deps-inspect /zenith/recipe.json recipe.json
-RUN ROCKSDB_LIB_DIR=/usr/lib/ cargo chef cook --release --recipe-path recipe.json
+RUN rm -rf postgres_install/build
 
 #
 # Build zenith binaries
 #
+# TODO: build cargo deps as separate layer. We used cargo-chef before but that was
+# net time waste in a lot of cases. Copying Cargo.lock with empty lib.rs should do the work.
+#
 FROM zenithdb/build:buster AS build
+
+ARG GIT_VERSION
+RUN if [ -z "$GIT_VERSION" ]; then echo "GIT_VERSION is reqired, use build_arg to pass it"; exit 1; fi
+
 WORKDIR /zenith
-COPY . .
-# Copy cached dependencies
 COPY --from=pg-build /zenith/tmp_install/include/postgresql/server tmp_install/include/postgresql/server
-COPY --from=deps-build /zenith/target target
-COPY --from=deps-build /usr/local/cargo/ /usr/local/cargo/
-RUN cargo build --release
+
+COPY . .
+RUN GIT_VERSION=$GIT_VERSION cargo build --release
 
 #
 # Copy binaries to resulting image.
@@ -51,11 +37,11 @@ RUN cargo build --release
 FROM debian:buster-slim
 WORKDIR /data
 
-RUN apt-get update && apt-get -yq install librocksdb-dev libseccomp-dev openssl && \
+RUN apt-get update && apt-get -yq install libreadline-dev libseccomp-dev openssl ca-certificates && \
     mkdir zenith_install
 
 COPY --from=build /zenith/target/release/pageserver /usr/local/bin
-COPY --from=build /zenith/target/release/wal_acceptor /usr/local/bin
+COPY --from=build /zenith/target/release/safekeeper /usr/local/bin
 COPY --from=build /zenith/target/release/proxy /usr/local/bin
 COPY --from=pg-build /zenith/tmp_install postgres_install
 COPY docker-entrypoint.sh /docker-entrypoint.sh
@@ -69,7 +55,7 @@ RUN rm -rf postgres_install/build && \
     cd postgres_install && tar -czf /data/postgres_install.tar.gz . && cd .. && \
     rm -rf postgres_install
 
-RUN useradd -m -d /data zenith
+RUN useradd -d /data zenith && chown -R zenith:zenith /data
 
 VOLUME ["/data"]
 USER zenith

Dockerfile.alpine

@@ -81,7 +81,7 @@ FROM alpine:3.13
 RUN apk add --update openssl build-base libseccomp-dev
 RUN apk --no-cache --update --repository https://dl-cdn.alpinelinux.org/alpine/edge/testing add rocksdb
 COPY --from=build /zenith/target/release/pageserver /usr/local/bin
-COPY --from=build /zenith/target/release/wal_acceptor /usr/local/bin
+COPY --from=build /zenith/target/release/safekeeper /usr/local/bin
 COPY --from=build /zenith/target/release/proxy /usr/local/bin
 COPY --from=pg-build /zenith/tmp_install /usr/local
 COPY docker-entrypoint.sh /docker-entrypoint.sh

Dockerfile.build

@@ -9,7 +9,7 @@ WORKDIR /zenith
 # Install postgres and zenith build dependencies
 # clang is for rocksdb
 RUN apt-get update && apt-get -yq install automake libtool build-essential bison flex libreadline-dev zlib1g-dev libxml2-dev \
-                                          libseccomp-dev pkg-config libssl-dev librocksdb-dev clang
+                                          libseccomp-dev pkg-config libssl-dev clang
 
 # Install rust tools
-RUN rustup component add clippy && cargo install cargo-chef cargo-audit
+RUN rustup component add clippy && cargo install cargo-audit

Makefile

@@ -6,47 +6,72 @@ else
 	SECCOMP =
 endif
 
+#
+# We differentiate between release / debug build types using the BUILD_TYPE
+# environment variable.
+#
+BUILD_TYPE ?= debug
+ifeq ($(BUILD_TYPE),release)
+	PG_CONFIGURE_OPTS = --enable-debug
+	PG_CFLAGS = -O2 -g3 $(CFLAGS)
+	# Unfortunately, `--profile=...` is a nightly feature
+	CARGO_BUILD_FLAGS += --release
+else ifeq ($(BUILD_TYPE),debug)
+	PG_CONFIGURE_OPTS = --enable-debug --enable-cassert --enable-depend
+	PG_CFLAGS = -O0 -g3 $(CFLAGS)
+else
+$(error Bad build type `$(BUILD_TYPE)', see Makefile for options)
+endif
+
+# Choose whether we should be silent or verbose
+CARGO_BUILD_FLAGS += --$(if $(filter s,$(MAKEFLAGS)),quiet,verbose)
+# Fix for a corner case when make doesn't pass a jobserver
+CARGO_BUILD_FLAGS += $(filter -j1,$(MAKEFLAGS))
+
+# This option has a side effect of passing make jobserver to cargo.
+# However, we shouldn't do this if `make -n` (--dry-run) has been asked.
+CARGO_CMD_PREFIX += $(if $(filter n,$(MAKEFLAGS)),,+)
+# Force cargo not to print progress bar
+CARGO_CMD_PREFIX += CARGO_TERM_PROGRESS_WHEN=never CI=1
+
 #
 # Top level Makefile to build Zenith and PostgreSQL
 #
+.PHONY: all
 all: zenith postgres
 
-# We don't want to run 'cargo build' in parallel with the postgres build,
-# because interleaving cargo build output with postgres build output looks
-# confusing. Also, 'cargo build' is parallel on its own, so it would be too
-# much parallelism. (Recursive invocation of postgres target still gets any
-# '-j' flag from the command line, so 'make -j' is still useful.)
-.NOTPARALLEL:
-
 ### Zenith Rust bits
 #
 # The 'postgres_ffi' depends on the Postgres headers.
+.PHONY: zenith
 zenith: postgres-headers
-	cargo build
+	+@echo "Compiling Zenith"
+	$(CARGO_CMD_PREFIX) cargo build $(CARGO_BUILD_FLAGS)
 
 ### PostgreSQL parts
 tmp_install/build/config.status:
 	+@echo "Configuring postgres build"
 	mkdir -p tmp_install/build
 	(cd tmp_install/build && \
-	../../vendor/postgres/configure CFLAGS='-O0 -g3 $(CFLAGS)' \
-		--enable-cassert \
-		--enable-debug \
-		--enable-depend \
+	../../vendor/postgres/configure CFLAGS='$(PG_CFLAGS)' \
+		$(PG_CONFIGURE_OPTS) \
 		$(SECCOMP) \
 		--prefix=$(abspath tmp_install) > configure.log)
 
 # nicer alias for running 'configure'
+.PHONY: postgres-configure
 postgres-configure: tmp_install/build/config.status
 
 # Install the PostgreSQL header files into tmp_install/include
+.PHONY: postgres-headers
 postgres-headers: postgres-configure
 	+@echo "Installing PostgreSQL headers"
 	$(MAKE) -C tmp_install/build/src/include MAKELEVEL=0 install
 
-
 # Compile and install PostgreSQL and contrib/zenith
-postgres: postgres-configure
+.PHONY: postgres
+postgres: postgres-configure \
+		  postgres-headers # to prevent `make install` conflicts with zenith's `postgres-headers`
 	+@echo "Compiling PostgreSQL"
 	$(MAKE) -C tmp_install/build MAKELEVEL=0 install
 	+@echo "Compiling contrib/zenith"
@@ -54,17 +79,26 @@ postgres: postgres-configure
 	+@echo "Compiling contrib/zenith_test_utils"
 	$(MAKE) -C tmp_install/build/contrib/zenith_test_utils install
 
+.PHONY: postgres-clean
 postgres-clean:
 	$(MAKE) -C tmp_install/build MAKELEVEL=0 clean
 
 # This doesn't remove the effects of 'configure'.
+.PHONY: clean
 clean:
-	cd tmp_install/build && ${MAKE} clean
-	cargo clean
+	cd tmp_install/build && $(MAKE) clean
+	$(CARGO_CMD_PREFIX) cargo clean
 
 # This removes everything
+.PHONY: distclean
 distclean:
 	rm -rf tmp_install
-	cargo clean
+	$(CARGO_CMD_PREFIX) cargo clean
 
-.PHONY: postgres-configure postgres postgres-headers zenith
+.PHONY: fmt
+fmt:
+	./pre-commit.py --fix-inplace
+
+.PHONY: setup-pre-commit-hook
+setup-pre-commit-hook:
+	ln -s -f ../../pre-commit.py .git/hooks/pre-commit

README.md

@@ -2,6 +2,22 @@
 
 Zenith substitutes PostgreSQL storage layer and redistributes data across a cluster of nodes
 
+## Architecture overview
+
+A Zenith installation consists of Compute nodes and Storage engine.
+
+Compute nodes are stateless PostgreSQL nodes, backed by zenith storage.
+
+Zenith storage engine consists of two major components:
+- Pageserver. Scalable storage backend for compute nodes.
+- WAL service. The service that receives WAL from compute node and ensures that it is stored durably.
+
+Pageserver consists of:
+- Repository - Zenith storage implementation.
+- WAL receiver - service that receives WAL from WAL service and stores it in the repository.
+- Page service - service that communicates with compute nodes and responds with pages from the repository.
+- WAL redo - service that builds pages from base images and WAL records on Page service request.
+
 ## Running local installation
 
 1. Install build dependencies and other useful packages
@@ -9,15 +25,15 @@ Zenith substitutes PostgreSQL storage layer and redistributes data across a clus
 On Ubuntu or Debian this set of packages should be sufficient to build the code:
 ```text
 apt install build-essential libtool libreadline-dev zlib1g-dev flex bison libseccomp-dev \
-libssl-dev clang
+libssl-dev clang pkg-config libpq-dev
 ```
 
-[Rust] 1.52 or later is also required.
+[Rust] 1.55 or later is also required.
 
 To run the `psql` client, install the `postgresql-client` package or modify `PATH` and `LD_LIBRARY_PATH` to include `tmp_install/bin` and `tmp_install/lib`, respectively.
 
 To run the integration tests (not required to use the code), install
-Python (3.6 or higher), and install python3 packages with `pipenv` using `pipenv install` in the project directory.
+Python (3.7 or higher), and install python3 packages with `pipenv` using `pipenv install` in the project directory.
 
 2. Build zenith and patched postgres
 ```sh
@@ -31,17 +47,26 @@ make -j5
 # Create repository in .zenith with proper paths to binaries and data
 # Later that would be responsibility of a package install script
 > ./target/debug/zenith init
+initializing tenantid c03ba6b7ad4c5e9cf556f059ade44229
+created initial timeline 5b014a9e41b4b63ce1a1febc04503636 timeline.lsn 0/169C3C8
+created main branch
 pageserver init succeeded
 
-# start pageserver
+# start pageserver and safekeeper
 > ./target/debug/zenith start
-Starting pageserver at '127.0.0.1:64000' in .zenith
+Starting pageserver at 'localhost:64000' in '.zenith'
 Pageserver started
+initializing for single for 7676
+Starting safekeeper at 'localhost:5454' in '.zenith/safekeepers/single'
+Safekeeper started
 
-# start postgres on top on the pageserver
+# start postgres compute node
 > ./target/debug/zenith pg start main
-Starting postgres node at 'host=127.0.0.1 port=55432 user=stas'
+Starting new postgres main on main...
+Extracting base backup to create postgres instance: path=.zenith/pgdatadirs/tenants/c03ba6b7ad4c5e9cf556f059ade44229/main port=55432
+Starting postgres node at 'host=127.0.0.1 port=55432 user=zenith_admin dbname=postgres'
 waiting for server to start.... done
+server started
 
 # check list of running postgres instances
 > ./target/debug/zenith pg list
@@ -51,7 +76,7 @@ main	127.0.0.1:55432	0/1609610	running
 
 4. Now it is possible to connect to postgres and run some queries:
 ```text
-> psql -p55432 -h 127.0.0.1 postgres
+> psql -p55432 -h 127.0.0.1 -U zenith_admin postgres
 postgres=# CREATE TABLE t(key int primary key, value text);
 CREATE TABLE
 postgres=# insert into t values(1,1);
@@ -81,7 +106,7 @@ waiting for server to start.... done
 
 # this new postgres instance will have all the data from 'main' postgres,
 # but all modifications would not affect data in original postgres
-> psql -p55433 -h 127.0.0.1 postgres
+> psql -p55433 -h 127.0.0.1 -U zenith_admin postgres
 postgres=# select * from t;
  key | value
 -----+-------
@@ -92,10 +117,16 @@ postgres=# insert into t values(2,2);
 INSERT 0 1
 ```
 
+6. If you want to run tests afterwards (see below), you have to stop all the running the pageserver, safekeeper and postgres instances
+   you have just started. You can stop them all with one command:
+```sh
+> ./target/debug/zenith stop
+```
+
 ## Running tests
 
 ```sh
-git clone --recursive https://github.com/libzenith/zenith.git
+git clone --recursive https://github.com/zenithdb/zenith.git
 make # builds also postgres and installs it to ./tmp_install
 cd test_runner
 pytest
@@ -105,52 +136,23 @@ pytest
 
 Now we use README files to cover design ideas and overall architecture for each module and `rustdoc` style documentation comments. See also [/docs/](/docs/) a top-level overview of all available markdown documentation.
 
+- [/docs/sourcetree.md](/docs/sourcetree.md) contains overview of source tree layout.
+
 To view your `rustdoc` documentation in a browser, try running `cargo doc --no-deps --open`
 
-## Source tree layout
+### Postgres-specific terms
 
-`/control_plane`:
+Due to Zenith's very close relation with PostgreSQL internals, there are numerous specific terms used.
+Same applies to certain spelling: i.e. we use MB to denote 1024 * 1024 bytes, while MiB would be technically more correct, it's inconsistent with what PostgreSQL code and its documentation use.
 
-Local control plane.
-Functions to start, configure and stop pageserver and postgres instances running as a local processes.
-Intended to be used in integration tests and in CLI tools for local installations.
+To get more familiar with this aspect, refer to:
 
-`/zenith`
+- [Zenith glossary](/docs/glossary.md)
+- [PostgreSQL glossary](https://www.postgresql.org/docs/13/glossary.html)
+- Other PostgreSQL documentation and sources (Zenith fork sources can be found [here](https://github.com/zenithdb/postgres))
 
-Main entry point for the 'zenith' CLI utility.
-TODO: Doesn't it belong to control_plane?
+## Join the development
 
-`/postgres_ffi`:
-
-Utility functions for interacting with PostgreSQL file formats.
-Misc constants, copied from PostgreSQL headers.
-
-`/zenith_utils`:
-
-Helpers that are shared between other crates in this repository.
-
-`/walkeeper`:
-
-WAL safekeeper (also known as WAL acceptor). Written in Rust.
-
-`/pageserver`:
-
-Page Server. Written in Rust.
-
-Depends on the modified 'postgres' binary for WAL redo.
-
-`/vendor/postgres`:
-
-PostgreSQL source tree, with the modifications needed for Zenith.
-
-`/vendor/postgres/contrib/zenith`:
-
-PostgreSQL extension that implements storage manager API and network communications with remote page server.
-
-`/test_runner`:
-
-Integration tests, written in Python using the `pytest` framework.
-
-`test_runner/zenith_regress`:
-
-Quick way to add new SQL regression test to integration tests set.
+- Read `CONTRIBUTING.md` to learn about project code style and practices.
+- To get familiar with a source tree layout, use [/docs/sourcetree.md](/docs/sourcetree.md).
+- To learn more about PostgreSQL internals, check http://www.interdb.jp/pg/index.html

control_plane/Cargo.toml

@@ -16,10 +16,12 @@ toml = "0.5"
 lazy_static = "1.4"
 regex = "1"
 anyhow = "1.0"
+thiserror = "1"
 bytes = "1.0.1"
-nix = "0.20"
+nix = "0.23"
 url = "2.2.2"
 hex = { version = "0.4.3", features = ["serde"] }
+reqwest = { version = "0.11", features = ["blocking", "json"] }
 
 pageserver = { path = "../pageserver" }
 walkeeper = { path = "../walkeeper" }

control_plane/safekeepers.conf

@@ -0,0 +1,20 @@
+# Page server and three safekeepers.
+[pageserver]
+pg_port = 64000
+http_port = 9898
+auth_type = 'Trust'
+
+[[safekeepers]]
+name = 'sk1'
+pg_port = 5454
+http_port = 7676
+
+[[safekeepers]]
+name = 'sk2'
+pg_port = 5455
+http_port = 7677
+
+[[safekeepers]]
+name = 'sk3'
+pg_port = 5456
+http_port = 7678

control_plane/simple.conf

@@ -0,0 +1,11 @@
+# Minimal zenith environment with one safekeeper. This is equivalent to the built-in
+# defaults that you get with no --config
+[pageserver]
+pg_port = 64000
+http_port = 9898
+auth_type = 'Trust'
+
+[[safekeepers]]
+name = 'single'
+pg_port = 5454
+http_port = 7676

control_plane/src/compute.rs

@@ -1,25 +1,24 @@
+use std::collections::BTreeMap;
+use std::fs::{self, File};
 use std::io::Write;
 use std::net::SocketAddr;
 use std::net::TcpStream;
 use std::os::unix::fs::PermissionsExt;
-use std::process::Command;
+use std::path::PathBuf;
+use std::process::{Command, Stdio};
+use std::str::FromStr;
 use std::sync::Arc;
 use std::time::Duration;
-use std::{collections::BTreeMap, path::PathBuf};
-use std::{
-    fs::{self, File, OpenOptions},
-    io::Read,
-};
 
 use anyhow::{Context, Result};
-use lazy_static::lazy_static;
-use regex::Regex;
 use zenith_utils::connstring::connection_host_port;
+use zenith_utils::lsn::Lsn;
 use zenith_utils::postgres_backend::AuthType;
 use zenith_utils::zid::ZTenantId;
 use zenith_utils::zid::ZTimelineId;
 
 use crate::local_env::LocalEnv;
+use crate::postgresql_conf::PostgresConf;
 use crate::storage::PageServerNode;
 
 //
@@ -40,8 +39,6 @@ impl ComputeControlPlane {
     // |  |- <tenant_id>
     // |  |   |- <branch name>
     pub fn load(env: LocalEnv) -> Result<ComputeControlPlane> {
-        // TODO: since pageserver do not have config file yet we believe here that
-        // it is running on default port. Change that when pageserver will have config.
         let pageserver = Arc::new(PageServerNode::from_env(&env));
 
         let mut nodes = BTreeMap::default();
@@ -76,53 +73,63 @@ impl ComputeControlPlane {
             .unwrap_or(self.base_port)
     }
 
-    pub fn local(local_env: &LocalEnv, pageserver: &Arc<PageServerNode>) -> ComputeControlPlane {
-        ComputeControlPlane {
-            base_port: 65431,
-            pageserver: Arc::clone(pageserver),
-            nodes: BTreeMap::new(),
-            env: local_env.clone(),
+    // FIXME: see also parse_point_in_time in branches.rs.
+    fn parse_point_in_time(
+        &self,
+        tenantid: ZTenantId,
+        s: &str,
+    ) -> Result<(ZTimelineId, Option<Lsn>)> {
+        let mut strings = s.split('@');
+        let name = strings.next().unwrap();
+
+        let lsn: Option<Lsn>;
+        if let Some(lsnstr) = strings.next() {
+            lsn = Some(
+                Lsn::from_str(lsnstr)
+                    .with_context(|| "invalid LSN in point-in-time specification")?,
+            );
+        } else {
+            lsn = None
         }
+
+        // Resolve the timeline ID, given the human-readable branch name
+        let timeline_id = self
+            .pageserver
+            .branch_get_by_name(&tenantid, name)?
+            .timeline_id;
+
+        Ok((timeline_id, lsn))
     }
 
     pub fn new_node(
         &mut self,
         tenantid: ZTenantId,
-        branch_name: &str,
-        config_only: bool,
+        name: &str,
+        timeline_spec: &str,
+        port: Option<u16>,
     ) -> Result<Arc<PostgresNode>> {
-        let timeline_id = self
-            .pageserver
-            .branch_get_by_name(&tenantid, branch_name)?
-            .timeline_id;
+        // Resolve the human-readable timeline spec into timeline ID and LSN
+        let (timelineid, lsn) = self.parse_point_in_time(tenantid, timeline_spec)?;
 
+        let port = port.unwrap_or_else(|| self.get_port());
         let node = Arc::new(PostgresNode {
-            name: branch_name.to_owned(),
-            address: SocketAddr::new("127.0.0.1".parse().unwrap(), self.get_port()),
+            name: name.to_owned(),
+            address: SocketAddr::new("127.0.0.1".parse().unwrap(), port),
             env: self.env.clone(),
             pageserver: Arc::clone(&self.pageserver),
             is_test: false,
-            timelineid: timeline_id,
+            timelineid,
+            lsn,
             tenantid,
+            uses_wal_proposer: false,
         });
 
-        node.init_from_page_server(self.env.auth_type, config_only)?;
+        node.create_pgdata()?;
+        node.setup_pg_conf(self.env.pageserver.auth_type)?;
+
         self.nodes
             .insert((tenantid, node.name.clone()), Arc::clone(&node));
 
-        // Configure the node to stream WAL directly to the pageserver
-        node.append_conf(
-            "postgresql.conf",
-            format!(
-                concat!(
-                    "synchronous_standby_names = 'pageserver'\n", // TODO: add a new function arg?
-                    "zenith.callmemaybe_connstring = '{}'\n",     // FIXME escaping
-                ),
-                node.connstr(),
-            )
-            .as_str(),
-        )?;
-
         Ok(node)
     }
 }
@@ -137,7 +144,9 @@ pub struct PostgresNode {
     pageserver: Arc<PageServerNode>,
     is_test: bool,
     pub timelineid: ZTimelineId,
+    pub lsn: Option<Lsn>, // if it's a read-only node. None for primary
     pub tenantid: ZTenantId,
+    uses_wal_proposer: bool,
 }
 
 impl PostgresNode {
@@ -153,74 +162,28 @@ impl PostgresNode {
             );
         }
 
-        lazy_static! {
-            static ref CONF_PORT_RE: Regex = Regex::new(r"(?m)^\s*port\s*=\s*(\d+)\s*$").unwrap();
-            static ref CONF_TIMELINE_RE: Regex =
-                Regex::new(r"(?m)^\s*zenith.zenith_timeline\s*=\s*'(\w+)'\s*$").unwrap();
-            static ref CONF_TENANT_RE: Regex =
-                Regex::new(r"(?m)^\s*zenith.zenith_tenant\s*=\s*'(\w+)'\s*$").unwrap();
-        }
-
         // parse data directory name
         let fname = entry.file_name();
         let name = fname.to_str().unwrap().to_string();
 
-        // find out tcp port in config file
+        // Read config file into memory
         let cfg_path = entry.path().join("postgresql.conf");
-        let config = fs::read_to_string(cfg_path.clone()).with_context(|| {
-            format!(
-                "failed to read config file in {}",
-                cfg_path.to_str().unwrap()
-            )
-        })?;
+        let cfg_path_str = cfg_path.to_string_lossy();
+        let mut conf_file = File::open(&cfg_path)
+            .with_context(|| format!("failed to open config file in {}", cfg_path_str))?;
+        let conf = PostgresConf::read(&mut conf_file)
+            .with_context(|| format!("failed to read config file in {}", cfg_path_str))?;
 
-        // parse port
-        let err_msg = format!(
-            "failed to find port definition in config file {}",
-            cfg_path.to_str().unwrap()
-        );
-        let port: u16 = CONF_PORT_RE
-            .captures(config.as_str())
-            .ok_or_else(|| anyhow::Error::msg(err_msg.clone() + " 1"))?
-            .iter()
-            .last()
-            .ok_or_else(|| anyhow::Error::msg(err_msg.clone() + " 2"))?
-            .ok_or_else(|| anyhow::Error::msg(err_msg.clone() + " 3"))?
-            .as_str()
-            .parse()
-            .with_context(|| err_msg)?;
+        // Read a few options from the config file
+        let context = format!("in config file {}", cfg_path_str);
+        let port: u16 = conf.parse_field("port", &context)?;
+        let timelineid: ZTimelineId = conf.parse_field("zenith.zenith_timeline", &context)?;
+        let tenantid: ZTenantId = conf.parse_field("zenith.zenith_tenant", &context)?;
+        let uses_wal_proposer = conf.get("wal_acceptors").is_some();
 
-        // parse timeline
-        let err_msg = format!(
-            "failed to find timeline definition in config file {}",
-            cfg_path.to_str().unwrap()
-        );
-        let timelineid: ZTimelineId = CONF_TIMELINE_RE
-            .captures(config.as_str())
-            .ok_or_else(|| anyhow::Error::msg(err_msg.clone() + " 1"))?
-            .iter()
-            .last()
-            .ok_or_else(|| anyhow::Error::msg(err_msg.clone() + " 2"))?
-            .ok_or_else(|| anyhow::Error::msg(err_msg.clone() + " 3"))?
-            .as_str()
-            .parse()
-            .with_context(|| err_msg)?;
-
-        // parse tenant
-        let err_msg = format!(
-            "failed to find tenant definition in config file {}",
-            cfg_path.to_str().unwrap()
-        );
-        let tenantid = CONF_TENANT_RE
-            .captures(config.as_str())
-            .ok_or_else(|| anyhow::Error::msg(err_msg.clone() + " 1"))?
-            .iter()
-            .last()
-            .ok_or_else(|| anyhow::Error::msg(err_msg.clone() + " 2"))?
-            .ok_or_else(|| anyhow::Error::msg(err_msg.clone() + " 3"))?
-            .as_str()
-            .parse()
-            .with_context(|| err_msg)?;
+        // parse recovery_target_lsn, if any
+        let recovery_target_lsn: Option<Lsn> =
+            conf.parse_field_optional("recovery_target_lsn", &context)?;
 
         // ok now
         Ok(PostgresNode {
@@ -230,124 +193,186 @@ impl PostgresNode {
             pageserver: Arc::clone(pageserver),
             is_test: false,
             timelineid,
+            lsn: recovery_target_lsn,
             tenantid,
+            uses_wal_proposer,
         })
     }
 
-    pub fn do_basebackup(&self) -> Result<()> {
-        let pgdata = self.pgdata();
+    fn sync_safekeepers(&self) -> Result<Lsn> {
+        let pg_path = self.env.pg_bin_dir().join("postgres");
+        let sync_handle = Command::new(pg_path)
+            .arg("--sync-safekeepers")
+            .env_clear()
+            .env("LD_LIBRARY_PATH", self.env.pg_lib_dir().to_str().unwrap())
+            .env("DYLD_LIBRARY_PATH", self.env.pg_lib_dir().to_str().unwrap())
+            .env("PGDATA", self.pgdata().to_str().unwrap())
+            .stdout(Stdio::piped())
+            // Comment this to avoid capturing stderr (useful if command hangs)
+            .stderr(Stdio::piped())
+            .spawn()
+            .expect("postgres --sync-safekeepers failed to start");
+
+        let sync_output = sync_handle
+            .wait_with_output()
+            .expect("postgres --sync-safekeepers failed");
+        if !sync_output.status.success() {
+            anyhow::bail!(
+                "sync-safekeepers failed: '{}'",
+                String::from_utf8_lossy(&sync_output.stderr)
+            );
+        }
+
+        let lsn = Lsn::from_str(std::str::from_utf8(&sync_output.stdout)?.trim())?;
+        println!("Safekeepers synced on {}", lsn);
+        Ok(lsn)
+    }
+
+    /// Get basebackup from the pageserver as a tar archive and extract it
+    /// to the `self.pgdata()` directory.
+    fn do_basebackup(&self, lsn: Option<Lsn>) -> Result<()> {
+        println!(
+            "Extracting base backup to create postgres instance: path={} port={}",
+            self.pgdata().display(),
+            self.address.port()
+        );
+
+        let sql = if let Some(lsn) = lsn {
+            format!("basebackup {} {} {}", self.tenantid, self.timelineid, lsn)
+        } else {
+            format!("basebackup {} {}", self.tenantid, self.timelineid)
+        };
 
-        let sql = format!("basebackup {} {}", self.tenantid, self.timelineid);
         let mut client = self
             .pageserver
             .page_server_psql_client()
             .with_context(|| "connecting to page server failed")?;
 
-        let mut copyreader = client
+        let copyreader = client
             .copy_out(sql.as_str())
             .with_context(|| "page server 'basebackup' command failed")?;
 
-        // FIXME: Currently, we slurp the whole tarball into memory, and then extract it,
-        // but we really should do this:
-        //let mut ar = tar::Archive::new(copyreader);
-        let mut buf = vec![];
-        copyreader
-            .read_to_end(&mut buf)
-            .with_context(|| "reading base backup from page server failed")?;
-        let mut ar = tar::Archive::new(buf.as_slice());
-        ar.unpack(&pgdata)
-            .with_context(|| "extracting page backup failed")?;
+        // Read the archive directly from the `CopyOutReader`
+        tar::Archive::new(copyreader)
+            .unpack(&self.pgdata())
+            .with_context(|| "extracting base backup failed")?;
 
         Ok(())
     }
 
-    // Connect to a page server, get base backup, and untar it to initialize a
-    // new data directory
-    pub fn init_from_page_server(&self, auth_type: AuthType, config_only: bool) -> Result<()> {
-        let pgdata = self.pgdata();
-
-        println!(
-            "Extracting base backup to create postgres instance: path={} port={}",
-            pgdata.display(),
-            self.address.port()
-        );
-
-        // initialize data directory
-        if self.is_test {
-            fs::remove_dir_all(&pgdata).ok();
-        }
-
-        fs::create_dir_all(&pgdata)
-            .with_context(|| format!("could not create data directory {}", pgdata.display()))?;
-        fs::set_permissions(pgdata.as_path(), fs::Permissions::from_mode(0o700)).with_context(
-            || {
+    fn create_pgdata(&self) -> Result<()> {
+        fs::create_dir_all(&self.pgdata()).with_context(|| {
+            format!(
+                "could not create data directory {}",
+                self.pgdata().display()
+            )
+        })?;
+        fs::set_permissions(self.pgdata().as_path(), fs::Permissions::from_mode(0o700))
+            .with_context(|| {
                 format!(
                     "could not set permissions in data directory {}",
-                    pgdata.display()
+                    self.pgdata().display()
                 )
-            },
-        )?;
-
-        if config_only {
-            //Just create an empty config file
-            File::create(self.pgdata().join("postgresql.conf").to_str().unwrap())?;
-        } else {
-            self.do_basebackup()?;
-            fs::create_dir_all(self.pgdata().join("pg_wal"))?;
-            fs::create_dir_all(self.pgdata().join("pg_wal").join("archive_status"))?;
-        }
+            })
+    }
 
+    // Connect to a page server, get base backup, and untar it to initialize a
+    // new data directory
+    fn setup_pg_conf(&self, auth_type: AuthType) -> Result<()> {
+        let mut conf = PostgresConf::new();
+        conf.append("max_wal_senders", "10");
         // wal_log_hints is mandatory when running against pageserver (see gh issue#192)
         // TODO: is it possible to check wal_log_hints at pageserver side via XLOG_PARAMETER_CHANGE?
-        self.append_conf(
-            "postgresql.conf",
-            &format!(
-                "max_wal_senders = 10\n\
-                 wal_log_hints = on\n\
-                 max_replication_slots = 10\n\
-                 hot_standby = on\n\
-                 shared_buffers = 1MB\n\
-                 fsync = off\n\
-                 max_connections = 100\n\
-                 wal_sender_timeout = 0\n\
-                 wal_level = replica\n\
-                 listen_addresses = '{address}'\n\
-                 port = {port}\n",
-                address = self.address.ip(),
-                port = self.address.port()
-            ),
-        )?;
+        conf.append("wal_log_hints", "on");
+        conf.append("max_replication_slots", "10");
+        conf.append("hot_standby", "on");
+        conf.append("shared_buffers", "1MB");
+        conf.append("fsync", "off");
+        conf.append("max_connections", "100");
+        conf.append("wal_sender_timeout", "0");
+        conf.append("wal_level", "replica");
+        conf.append("listen_addresses", &self.address.ip().to_string());
+        conf.append("port", &self.address.port().to_string());
 
         // Never clean up old WAL. TODO: We should use a replication
         // slot or something proper, to prevent the compute node
         // from removing WAL that hasn't been streamed to the safekeeper or
         // page server yet. (gh issue #349)
-        self.append_conf("postgresql.conf", "wal_keep_size='10TB'\n")?;
+        conf.append("wal_keep_size", "10TB");
 
-        // set up authentication
-        let password = if let AuthType::ZenithJWT = auth_type {
-            "$ZENITH_AUTH_TOKEN"
+        // Configure the node to fetch pages from pageserver
+        let pageserver_connstr = {
+            let (host, port) = connection_host_port(&self.pageserver.pg_connection_config);
+
+            // Set up authentication
+            //
+            // $ZENITH_AUTH_TOKEN will be replaced with value from environment
+            // variable during compute pg startup. It is done this way because
+            // otherwise user will be able to retrieve the value using SHOW
+            // command or pg_settings
+            let password = if let AuthType::ZenithJWT = auth_type {
+                "$ZENITH_AUTH_TOKEN"
+            } else {
+                ""
+            };
+
+            format!("host={} port={} password={}", host, port, password)
+        };
+        conf.append("shared_preload_libraries", "zenith");
+        conf.append_line("");
+        conf.append("zenith.page_server_connstring", &pageserver_connstr);
+        conf.append("zenith.zenith_tenant", &self.tenantid.to_string());
+        conf.append("zenith.zenith_timeline", &self.timelineid.to_string());
+        if let Some(lsn) = self.lsn {
+            conf.append("recovery_target_lsn", &lsn.to_string());
+        }
+        conf.append_line("");
+
+        if !self.env.safekeepers.is_empty() {
+            // Configure the node to connect to the safekeepers
+            conf.append("synchronous_standby_names", "walproposer");
+
+            let wal_acceptors = self
+                .env
+                .safekeepers
+                .iter()
+                .map(|sk| format!("localhost:{}", sk.pg_port))
+                .collect::<Vec<String>>()
+                .join(",");
+            conf.append("wal_acceptors", &wal_acceptors);
         } else {
-            ""
+            // Configure the node to stream WAL directly to the pageserver
+            // This isn't really a supported configuration, but can be useful for
+            // testing.
+            conf.append("synchronous_standby_names", "pageserver");
+            conf.append("zenith.callmemaybe_connstring", &self.connstr());
+        }
+
+        let mut file = File::create(self.pgdata().join("postgresql.conf"))?;
+        file.write_all(conf.to_string().as_bytes())?;
+
+        Ok(())
+    }
+
+    fn load_basebackup(&self) -> Result<()> {
+        let backup_lsn = if let Some(lsn) = self.lsn {
+            Some(lsn)
+        } else if self.uses_wal_proposer {
+            // LSN 0 means that it is bootstrap and we need to download just
+            // latest data from the pageserver. That is a bit clumsy but whole bootstrap
+            // procedure evolves quite actively right now, so let's think about it again
+            // when things would be more stable (TODO).
+            let lsn = self.sync_safekeepers()?;
+            if lsn == Lsn(0) {
+                None
+            } else {
+                Some(lsn)
+            }
+        } else {
+            None
         };
 
-        // Configure that node to take pages from pageserver
-        let (host, port) = connection_host_port(&self.pageserver.connection_config);
-        self.append_conf(
-            "postgresql.conf",
-            format!(
-                concat!(
-                    "shared_preload_libraries = zenith\n",
-                    // $ZENITH_AUTH_TOKEN will be replaced with value from environment variable during compute pg startup
-                    // it is done this way because otherwise user will be able to retrieve the value using SHOW command or pg_settings
-                    "zenith.page_server_connstring = 'host={} port={} password={}'\n",
-                    "zenith.zenith_timeline='{}'\n",
-                    "zenith.zenith_tenant='{}'\n",
-                ),
-                host, port, password, self.timelineid, self.tenantid,
-            )
-            .as_str(),
-        )?;
+        self.do_basebackup(backup_lsn)?;
 
         Ok(())
     }
@@ -369,14 +394,6 @@ impl PostgresNode {
         }
     }
 
-    pub fn append_conf(&self, config: &str, opts: &str) -> Result<()> {
-        OpenOptions::new()
-            .append(true)
-            .open(self.pgdata().join(config).to_str().unwrap())?
-            .write_all(opts.as_bytes())?;
-        Ok(())
-    }
-
     fn pg_ctl(&self, args: &[&str], auth_token: &Option<String>) -> Result<()> {
         let pg_ctl_path = self.env.pg_bin_dir().join("pg_ctl");
         let mut cmd = Command::new(pg_ctl_path);
@@ -415,37 +432,25 @@ impl PostgresNode {
         }
 
         // 1. We always start compute node from scratch, so
-        // if old dir exists, preserve config files and drop the directory
-
-        // XXX Now we only use 'postgresql.conf'.
-        // If we will need 'pg_hba.conf', support it here too
-
+        // if old dir exists, preserve 'postgresql.conf' and drop the directory
         let postgresql_conf_path = self.pgdata().join("postgresql.conf");
-        let postgresql_conf = fs::read(postgresql_conf_path.clone()).with_context(|| {
+        let postgresql_conf = fs::read(&postgresql_conf_path).with_context(|| {
             format!(
                 "failed to read config file in {}",
                 postgresql_conf_path.to_str().unwrap()
             )
         })?;
-
-        println!(
-            "Destroying postgres data directory '{}'",
-            self.pgdata().to_str().unwrap()
-        );
         fs::remove_dir_all(&self.pgdata())?;
+        self.create_pgdata()?;
 
-        // 2. Create new node
-        self.init_from_page_server(self.env.auth_type, false)?;
+        // 2. Bring back config files
+        fs::write(&postgresql_conf_path, postgresql_conf)?;
 
-        // 3. Bring back config files
+        // 3. Load basebackup
+        self.load_basebackup()?;
 
-        if let Ok(mut file) = OpenOptions::new()
-            .append(false)
-            .write(true)
-            .open(&postgresql_conf_path)
-        {
-            file.write_all(&postgresql_conf)?;
-            file.sync_all()?;
+        if self.lsn.is_some() {
+            File::create(self.pgdata().join("standby.signal"))?;
         }
 
         // 4. Finally start the compute node postgres
@@ -458,13 +463,22 @@ impl PostgresNode {
     }
 
     pub fn stop(&self, destroy: bool) -> Result<()> {
-        self.pg_ctl(&["-m", "immediate", "stop"], &None)?;
+        // If we are going to destroy data directory,
+        // use immediate shutdown mode, otherwise,
+        // shutdown gracefully to leave the data directory sane.
+        //
+        // Compute node always starts from scratch, so stop
+        // without destroy only used for testing and debugging.
+        //
         if destroy {
+            self.pg_ctl(&["-m", "immediate", "stop"], &None)?;
             println!(
                 "Destroying postgres data directory '{}'",
                 self.pgdata().to_str().unwrap()
             );
             fs::remove_dir_all(&self.pgdata())?;
+        } else {
+            self.pg_ctl(&["stop"], &None)?;
         }
         Ok(())
     }
@@ -485,9 +499,7 @@ impl PostgresNode {
             .output()
             .expect("failed to execute whoami");
 
-        if !output.status.success() {
-            panic!("whoami failed");
-        }
+        assert!(output.status.success(), "whoami failed");
 
         String::from_utf8(output.stdout).unwrap().trim().to_string()
     }

control_plane/src/lib.rs

@@ -12,6 +12,8 @@ use std::path::Path;
 
 pub mod compute;
 pub mod local_env;
+pub mod postgresql_conf;
+pub mod safekeeper;
 pub mod storage;
 
 /// Read a PID file

control_plane/src/local_env.rs

@@ -4,57 +4,105 @@
 // Now it also provides init method which acts like a stub for proper installation
 // script which will use local paths.
 //
-use anyhow::{anyhow, Context, Result};
-use hex;
+use anyhow::{Context, Result};
 use serde::{Deserialize, Serialize};
+use std::env;
+use std::fmt::Write;
 use std::fs;
-use std::path::PathBuf;
+use std::path::{Path, PathBuf};
 use std::process::{Command, Stdio};
-use std::{collections::BTreeMap, env};
-use url::Url;
-use zenith_utils::auth::{encode_from_key_path, Claims, Scope};
+use zenith_utils::auth::{encode_from_key_file, Claims, Scope};
 use zenith_utils::postgres_backend::AuthType;
 use zenith_utils::zid::ZTenantId;
 
-pub type Remotes = BTreeMap<String, String>;
-
 //
-// This data structures represent deserialized zenith CLI config
+// This data structures represents zenith CLI config
+//
+// It is deserialized from the .zenith/config file, or the config file passed
+// to 'zenith init --config=<path>' option. See control_plane/simple.conf for
+// an example.
 //
 #[derive(Serialize, Deserialize, Clone, Debug)]
 pub struct LocalEnv {
-    // Pageserver connection strings
-    pub pageserver_connstring: String,
-
-    // Base directory for both pageserver and compute nodes
+    // Base directory for all the nodes (the pageserver, safekeepers and
+    // compute nodes).
+    //
+    // This is not stored in the config file. Rather, this is the path where the
+    // config file itself is. It is read from the ZENITH_REPO_DIR env variable or
+    // '.zenith' if not given.
+    #[serde(skip)]
     pub base_data_dir: PathBuf,
 
     // Path to postgres distribution. It's expected that "bin", "include",
     // "lib", "share" from postgres distribution are there. If at some point
     // in time we will be able to run against vanilla postgres we may split that
     // to four separate paths and match OS-specific installation layout.
+    #[serde(default)]
     pub pg_distrib_dir: PathBuf,
 
-    // Path to pageserver binary. Empty for remote pageserver.
-    pub zenith_distrib_dir: Option<PathBuf>,
+    // Path to pageserver binary.
+    #[serde(default)]
+    pub zenith_distrib_dir: PathBuf,
 
-    // keeping tenant id in config to reduce copy paste when running zenith locally with single tenant
-    #[serde(with = "hex")]
-    pub tenantid: ZTenantId,
+    // Default tenant ID to use with the 'zenith' command line utility, when
+    // --tenantid is not explicitly specified.
+    #[serde(with = "opt_tenantid_serde")]
+    #[serde(default)]
+    pub default_tenantid: Option<ZTenantId>,
 
-    // Repository format, 'rocksdb' or 'layered' or None for default
-    pub repository_format: Option<String>,
+    // used to issue tokens during e.g pg start
+    #[serde(default)]
+    pub private_key_path: PathBuf,
 
-    // jwt auth token used for communication with pageserver
-    pub auth_token: String,
+    pub pageserver: PageServerConf,
+
+    #[serde(default)]
+    pub safekeepers: Vec<SafekeeperConf>,
+}
+
+#[derive(Serialize, Deserialize, Clone, Debug)]
+#[serde(default)]
+pub struct PageServerConf {
+    // Pageserver connection settings
+    pub pg_port: u16,
+    pub http_port: u16,
 
     // used to determine which auth type is used
     pub auth_type: AuthType,
 
-    // used to issue tokens during e.g pg start
-    pub private_key_path: PathBuf,
+    // jwt auth token used for communication with pageserver
+    pub auth_token: String,
+}
 
-    pub remotes: Remotes,
+impl Default for PageServerConf {
+    fn default() -> Self {
+        Self {
+            pg_port: 0,
+            http_port: 0,
+            auth_type: AuthType::Trust,
+            auth_token: "".to_string(),
+        }
+    }
+}
+
+#[derive(Serialize, Deserialize, Clone, Debug)]
+#[serde(default)]
+pub struct SafekeeperConf {
+    pub name: String,
+    pub pg_port: u16,
+    pub http_port: u16,
+    pub sync: bool,
+}
+
+impl Default for SafekeeperConf {
+    fn default() -> Self {
+        Self {
+            name: "".to_string(),
+            pg_port: 0,
+            http_port: 0,
+            sync: true,
+        }
+    }
 }
 
 impl LocalEnv {
@@ -67,11 +115,11 @@ impl LocalEnv {
     }
 
     pub fn pageserver_bin(&self) -> Result<PathBuf> {
-        Ok(self
-            .zenith_distrib_dir
-            .as_ref()
-            .ok_or_else(|| anyhow!("Can not manage remote pageserver"))?
-            .join("pageserver"))
+        Ok(self.zenith_distrib_dir.join("pageserver"))
+    }
+
+    pub fn safekeeper_bin(&self) -> Result<PathBuf> {
+        Ok(self.zenith_distrib_dir.join("safekeeper"))
     }
 
     pub fn pg_data_dirs_path(&self) -> PathBuf {
@@ -88,6 +136,187 @@ impl LocalEnv {
     pub fn pageserver_data_dir(&self) -> PathBuf {
         self.base_data_dir.clone()
     }
+
+    pub fn safekeeper_data_dir(&self, node_name: &str) -> PathBuf {
+        self.base_data_dir.join("safekeepers").join(node_name)
+    }
+
+    /// Create a LocalEnv from a config file.
+    ///
+    /// Unlike 'load_config', this function fills in any defaults that are missing
+    /// from the config file.
+    pub fn create_config(toml: &str) -> Result<LocalEnv> {
+        let mut env: LocalEnv = toml::from_str(toml)?;
+
+        // Find postgres binaries.
+        // Follow POSTGRES_DISTRIB_DIR if set, otherwise look in "tmp_install".
+        if env.pg_distrib_dir == Path::new("") {
+            if let Some(postgres_bin) = env::var_os("POSTGRES_DISTRIB_DIR") {
+                env.pg_distrib_dir = postgres_bin.into();
+            } else {
+                let cwd = env::current_dir()?;
+                env.pg_distrib_dir = cwd.join("tmp_install")
+            }
+        }
+        if !env.pg_distrib_dir.join("bin/postgres").exists() {
+            anyhow::bail!(
+                "Can't find postgres binary at {}",
+                env.pg_distrib_dir.display()
+            );
+        }
+
+        // Find zenith binaries.
+        if env.zenith_distrib_dir == Path::new("") {
+            env.zenith_distrib_dir = env::current_exe()?.parent().unwrap().to_owned();
+        }
+        if !env.zenith_distrib_dir.join("pageserver").exists() {
+            anyhow::bail!("Can't find pageserver binary.");
+        }
+        if !env.zenith_distrib_dir.join("safekeeper").exists() {
+            anyhow::bail!("Can't find safekeeper binary.");
+        }
+
+        // If no initial tenant ID was given, generate it.
+        if env.default_tenantid.is_none() {
+            env.default_tenantid = Some(ZTenantId::generate());
+        }
+
+        env.base_data_dir = base_path();
+
+        Ok(env)
+    }
+
+    /// Locate and load config
+    pub fn load_config() -> Result<LocalEnv> {
+        let repopath = base_path();
+
+        if !repopath.exists() {
+            anyhow::bail!(
+                "Zenith config is not found in {}. You need to run 'zenith init' first",
+                repopath.to_str().unwrap()
+            );
+        }
+
+        // TODO: check that it looks like a zenith repository
+
+        // load and parse file
+        let config = fs::read_to_string(repopath.join("config"))?;
+        let mut env: LocalEnv = toml::from_str(config.as_str())?;
+
+        env.base_data_dir = repopath;
+
+        Ok(env)
+    }
+
+    // this function is used only for testing purposes in CLI e g generate tokens during init
+    pub fn generate_auth_token(&self, claims: &Claims) -> Result<String> {
+        let private_key_path = if self.private_key_path.is_absolute() {
+            self.private_key_path.to_path_buf()
+        } else {
+            self.base_data_dir.join(&self.private_key_path)
+        };
+
+        let key_data = fs::read(private_key_path)?;
+        encode_from_key_file(claims, &key_data)
+    }
+
+    //
+    // Initialize a new Zenith repository
+    //
+    pub fn init(&mut self) -> Result<()> {
+        // check if config already exists
+        let base_path = &self.base_data_dir;
+        if base_path == Path::new("") {
+            anyhow::bail!("repository base path is missing");
+        }
+        if base_path.exists() {
+            anyhow::bail!(
+                "directory '{}' already exists. Perhaps already initialized?",
+                base_path.to_str().unwrap()
+            );
+        }
+
+        fs::create_dir(&base_path)?;
+
+        // generate keys for jwt
+        // openssl genrsa -out private_key.pem 2048
+        let private_key_path;
+        if self.private_key_path == PathBuf::new() {
+            private_key_path = base_path.join("auth_private_key.pem");
+            let keygen_output = Command::new("openssl")
+                .arg("genrsa")
+                .args(&["-out", private_key_path.to_str().unwrap()])
+                .arg("2048")
+                .stdout(Stdio::null())
+                .output()
+                .with_context(|| "failed to generate auth private key")?;
+            if !keygen_output.status.success() {
+                anyhow::bail!(
+                    "openssl failed: '{}'",
+                    String::from_utf8_lossy(&keygen_output.stderr)
+                );
+            }
+            self.private_key_path = Path::new("auth_private_key.pem").to_path_buf();
+
+            let public_key_path = base_path.join("auth_public_key.pem");
+            // openssl rsa -in private_key.pem -pubout -outform PEM -out public_key.pem
+            let keygen_output = Command::new("openssl")
+                .arg("rsa")
+                .args(&["-in", private_key_path.to_str().unwrap()])
+                .arg("-pubout")
+                .args(&["-outform", "PEM"])
+                .args(&["-out", public_key_path.to_str().unwrap()])
+                .stdout(Stdio::null())
+                .output()
+                .with_context(|| "failed to generate auth private key")?;
+            if !keygen_output.status.success() {
+                anyhow::bail!(
+                    "openssl failed: '{}'",
+                    String::from_utf8_lossy(&keygen_output.stderr)
+                );
+            }
+        }
+
+        self.pageserver.auth_token =
+            self.generate_auth_token(&Claims::new(None, Scope::PageServerApi))?;
+
+        fs::create_dir_all(self.pg_data_dirs_path())?;
+
+        for safekeeper in self.safekeepers.iter() {
+            fs::create_dir_all(self.safekeeper_data_dir(&safekeeper.name))?;
+        }
+
+        let mut conf_content = String::new();
+
+        // Currently, the user first passes a config file with 'zenith init --config=<path>'
+        // We read that in, in `create_config`, and fill any missing defaults. Then it's saved
+        // to .zenith/config. TODO: We lose any formatting and comments along the way, which is
+        // a bit sad.
+        write!(
+            &mut conf_content,
+            r#"# This file describes a locale deployment of the page server
+# and safekeeeper node. It is read by the 'zenith' command-line
+# utility.
+"#
+        )?;
+
+        // Convert the LocalEnv to a toml file.
+        //
+        // This could be as simple as this:
+        //
+        // conf_content += &toml::to_string_pretty(env)?;
+        //
+        // But it results in a "values must be emitted before tables". I'm not sure
+        // why, AFAICS the table, i.e. 'safekeepers: Vec<SafekeeperConf>' is last.
+        // Maybe rust reorders the fields to squeeze avoid padding or something?
+        // In any case, converting to toml::Value first, and serializing that, works.
+        // See https://github.com/alexcrichton/toml-rs/issues/142
+        conf_content += &toml::to_string_pretty(&toml::Value::try_from(&self)?)?;
+
+        fs::write(base_path.join("config"), conf_content)?;
+
+        Ok(())
+    }
 }
 
 fn base_path() -> PathBuf {
@@ -97,146 +326,29 @@ fn base_path() -> PathBuf {
     }
 }
 
-//
-// Initialize a new Zenith repository
-//
-pub fn init(
-    remote_pageserver: Option<&str>,
-    tenantid: ZTenantId,
-    auth_type: AuthType,
-    repository_format: Option<&str>,
-) -> Result<()> {
-    // check if config already exists
-    let base_path = base_path();
-    if base_path.exists() {
-        anyhow::bail!(
-            "{} already exists. Perhaps already initialized?",
-            base_path.to_str().unwrap()
-        );
-    }
-    fs::create_dir(&base_path)?;
+/// Serde routines for Option<ZTenantId>. The serialized form is a hex string.
+mod opt_tenantid_serde {
+    use serde::{Deserialize, Deserializer, Serialize, Serializer};
+    use std::str::FromStr;
+    use zenith_utils::zid::ZTenantId;
 
-    // ok, now check that expected binaries are present
-
-    // Find postgres binaries. Follow POSTGRES_DISTRIB_DIR if set, otherwise look in "tmp_install".
-    let pg_distrib_dir: PathBuf = {
-        if let Some(postgres_bin) = env::var_os("POSTGRES_DISTRIB_DIR") {
-            postgres_bin.into()
-        } else {
-            let cwd = env::current_dir()?;
-            cwd.join("tmp_install")
-        }
-    };
-    if !pg_distrib_dir.join("bin/postgres").exists() {
-        anyhow::bail!("Can't find postgres binary at {:?}", pg_distrib_dir);
+    pub fn serialize<S>(tenantid: &Option<ZTenantId>, ser: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        tenantid.map(|t| t.to_string()).serialize(ser)
     }
 
-    // generate keys for jwt
-    // openssl genrsa -out private_key.pem 2048
-    let private_key_path = base_path.join("auth_private_key.pem");
-    let keygen_output = Command::new("openssl")
-        .arg("genrsa")
-        .args(&["-out", private_key_path.to_str().unwrap()])
-        .arg("2048")
-        .stdout(Stdio::null())
-        .output()
-        .with_context(|| "failed to generate auth private key")?;
-    if !keygen_output.status.success() {
-        anyhow::bail!(
-            "openssl failed: '{}'",
-            String::from_utf8_lossy(&keygen_output.stderr)
-        );
+    pub fn deserialize<'de, D>(des: D) -> Result<Option<ZTenantId>, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        let s: Option<String> = Option::deserialize(des)?;
+        if let Some(s) = s {
+            return Ok(Some(
+                ZTenantId::from_str(&s).map_err(serde::de::Error::custom)?,
+            ));
+        }
+        Ok(None)
     }
-
-    let public_key_path = base_path.join("auth_public_key.pem");
-    // openssl rsa -in private_key.pem -pubout -outform PEM -out public_key.pem
-    let keygen_output = Command::new("openssl")
-        .arg("rsa")
-        .args(&["-in", private_key_path.to_str().unwrap()])
-        .arg("-pubout")
-        .args(&["-outform", "PEM"])
-        .args(&["-out", public_key_path.to_str().unwrap()])
-        .stdout(Stdio::null())
-        .output()
-        .with_context(|| "failed to generate auth private key")?;
-    if !keygen_output.status.success() {
-        anyhow::bail!(
-            "openssl failed: '{}'",
-            String::from_utf8_lossy(&keygen_output.stderr)
-        );
-    }
-
-    let auth_token =
-        encode_from_key_path(&Claims::new(None, Scope::PageServerApi), &private_key_path)?;
-
-    let conf = if let Some(addr) = remote_pageserver {
-        // check that addr is parsable
-        let _uri = Url::parse(addr).map_err(|e| anyhow!("{}: {}", addr, e))?;
-
-        LocalEnv {
-            pageserver_connstring: format!("postgresql://{}/", addr),
-            pg_distrib_dir,
-            zenith_distrib_dir: None,
-            base_data_dir: base_path,
-            remotes: BTreeMap::default(),
-            tenantid,
-            repository_format: repository_format.map(|x| x.into()),
-            auth_token,
-            auth_type,
-            private_key_path,
-        }
-    } else {
-        // Find zenith binaries.
-        let zenith_distrib_dir = env::current_exe()?.parent().unwrap().to_owned();
-        if !zenith_distrib_dir.join("pageserver").exists() {
-            anyhow::bail!("Can't find pageserver binary.",);
-        }
-
-        LocalEnv {
-            pageserver_connstring: "postgresql://127.0.0.1:6400".to_string(),
-            pg_distrib_dir,
-            zenith_distrib_dir: Some(zenith_distrib_dir),
-            base_data_dir: base_path,
-            remotes: BTreeMap::default(),
-            tenantid,
-            repository_format: repository_format.map(|x| x.into()),
-            auth_token,
-            auth_type,
-            private_key_path,
-        }
-    };
-
-    fs::create_dir_all(conf.pg_data_dirs_path())?;
-
-    let toml = toml::to_string_pretty(&conf)?;
-    fs::write(conf.base_data_dir.join("config"), toml)?;
-
-    Ok(())
-}
-
-// Locate and load config
-pub fn load_config() -> Result<LocalEnv> {
-    let repopath = base_path();
-
-    if !repopath.exists() {
-        anyhow::bail!(
-            "Zenith config is not found in {}. You need to run 'zenith init' first",
-            repopath.to_str().unwrap()
-        );
-    }
-
-    // TODO: check that it looks like a zenith repository
-
-    // load and parse file
-    let config = fs::read_to_string(repopath.join("config"))?;
-    toml::from_str(config.as_str()).map_err(|e| e.into())
-}
-
-// Save config. We use that to change set of remotes from CLI itself.
-pub fn save_config(conf: &LocalEnv) -> Result<()> {
-    let config_path = base_path().join("config");
-    let conf_str = toml::to_string_pretty(conf)?;
-
-    fs::write(config_path, conf_str)?;
-    Ok(())
 }

control_plane/src/postgresql_conf.rs

@@ -0,0 +1,228 @@
+///
+/// Module for parsing postgresql.conf file.
+///
+/// NOTE: This doesn't implement the full, correct postgresql.conf syntax. Just
+/// enough to extract a few settings we need in Zenith, assuming you don't do
+/// funny stuff like include-directives or funny escaping.
+use anyhow::{anyhow, bail, Context, Result};
+use lazy_static::lazy_static;
+use regex::Regex;
+use std::collections::HashMap;
+use std::fmt;
+use std::io::BufRead;
+use std::str::FromStr;
+
+/// In-memory representation of a postgresql.conf file
+#[derive(Default)]
+pub struct PostgresConf {
+    lines: Vec<String>,
+    hash: HashMap<String, String>,
+}
+
+lazy_static! {
+    static ref CONF_LINE_RE: Regex = Regex::new(r"^((?:\w|\.)+)\s*=\s*(\S+)$").unwrap();
+}
+
+impl PostgresConf {
+    pub fn new() -> PostgresConf {
+        PostgresConf::default()
+    }
+
+    /// Read file into memory
+    pub fn read(read: impl std::io::Read) -> Result<PostgresConf> {
+        let mut result = Self::new();
+
+        for line in std::io::BufReader::new(read).lines() {
+            let line = line?;
+
+            // Store each line in a vector, in original format
+            result.lines.push(line.clone());
+
+            // Also parse each line and insert key=value lines into a hash map.
+            //
+            // FIXME: This doesn't match exactly the flex/bison grammar in PostgreSQL.
+            // But it's close enough for our usage.
+            let line = line.trim();
+            if line.starts_with('#') {
+                // comment, ignore
+                continue;
+            } else if let Some(caps) = CONF_LINE_RE.captures(line) {
+                let name = caps.get(1).unwrap().as_str();
+                let raw_val = caps.get(2).unwrap().as_str();
+
+                if let Ok(val) = deescape_str(raw_val) {
+                    // Note: if there's already an entry in the hash map for
+                    // this key, this will replace it. That's the behavior what
+                    // we want; when PostgreSQL reads the file, each line
+                    // overrides any previous value for the same setting.
+                    result.hash.insert(name.to_string(), val.to_string());
+                }
+            }
+        }
+        Ok(result)
+    }
+
+    /// Return the current value of 'option'
+    pub fn get(&self, option: &str) -> Option<&str> {
+        self.hash.get(option).map(|x| x.as_ref())
+    }
+
+    /// Return the current value of a field, parsed to the right datatype.
+    ///
+    /// This calls the FromStr::parse() function on the value of the field. If
+    /// the field does not exist, or parsing fails, returns an error.
+    ///
+    pub fn parse_field<T>(&self, field_name: &str, context: &str) -> Result<T>
+    where
+        T: FromStr,
+        <T as FromStr>::Err: std::error::Error + Send + Sync + 'static,
+    {
+        self.get(field_name)
+            .ok_or_else(|| anyhow!("could not find '{}' option {}", field_name, context))?
+            .parse::<T>()
+            .with_context(|| format!("could not parse '{}' option {}", field_name, context))
+    }
+
+    pub fn parse_field_optional<T>(&self, field_name: &str, context: &str) -> Result<Option<T>>
+    where
+        T: FromStr,
+        <T as FromStr>::Err: std::error::Error + Send + Sync + 'static,
+    {
+        if let Some(val) = self.get(field_name) {
+            let result = val
+                .parse::<T>()
+                .with_context(|| format!("could not parse '{}' option {}", field_name, context))?;
+
+            Ok(Some(result))
+        } else {
+            Ok(None)
+        }
+    }
+
+    ///
+    /// Note: if you call this multiple times for the same option, the config
+    /// file will a line for each call. It would be nice to have a function
+    /// to change an existing line, but that's a TODO.
+    ///
+    pub fn append(&mut self, option: &str, value: &str) {
+        self.lines
+            .push(format!("{}={}\n", option, escape_str(value)));
+        self.hash.insert(option.to_string(), value.to_string());
+    }
+
+    /// Append an arbitrary non-setting line to the config file
+    pub fn append_line(&mut self, line: &str) {
+        self.lines.push(line.to_string());
+    }
+}
+
+impl fmt::Display for PostgresConf {
+    /// Return the whole configuration file as a string
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        for line in self.lines.iter() {
+            f.write_str(line)?;
+        }
+        Ok(())
+    }
+}
+
+/// Escape a value for putting in postgresql.conf.
+fn escape_str(s: &str) -> String {
+    // If the string doesn't contain anything that needs quoting or escaping, return it
+    // as it is.
+    //
+    // The first part of the regex, before the '|', matches the INTEGER rule in the
+    // PostgreSQL flex grammar (guc-file.l). It matches plain integers like "123" and
+    // "-123", and also accepts units like "10MB". The second part of the regex matches
+    // the UNQUOTED_STRING rule, and accepts strings that contain a single word, beginning
+    // with a letter. That covers words like "off" or "posix". Everything else is quoted.
+    //
+    // This regex is a bit more conservative than the rules in guc-file.l, so we quote some
+    // strings that PostgreSQL would accept without quoting, but that's OK.
+    lazy_static! {
+        static ref UNQUOTED_RE: Regex =
+            Regex::new(r"(^[-+]?[0-9]+[a-zA-Z]*$)|(^[a-zA-Z][a-zA-Z0-9]*$)").unwrap();
+    }
+    if UNQUOTED_RE.is_match(s) {
+        s.to_string()
+    } else {
+        // Otherwise escape and quote it
+        let s = s
+            .replace('\\', "\\\\")
+            .replace('\n', "\\n")
+            .replace('\'', "''");
+
+        "\'".to_owned() + &s + "\'"
+    }
+}
+
+/// De-escape a possibly-quoted value.
+///
+/// See `DeescapeQuotedString` function in PostgreSQL sources for how PostgreSQL
+/// does this.
+fn deescape_str(s: &str) -> Result<String> {
+    // If the string has a quote at the beginning and end, strip them out.
+    if s.len() >= 2 && s.starts_with('\'') && s.ends_with('\'') {
+        let mut result = String::new();
+
+        let mut iter = s[1..(s.len() - 1)].chars().peekable();
+        while let Some(c) = iter.next() {
+            let newc = if c == '\\' {
+                match iter.next() {
+                    Some('b') => '\x08',
+                    Some('f') => '\x0c',
+                    Some('n') => '\n',
+                    Some('r') => '\r',
+                    Some('t') => '\t',
+                    Some('0'..='7') => {
+                        // TODO
+                        bail!("octal escapes not supported");
+                    }
+                    Some(n) => n,
+                    None => break,
+                }
+            } else if c == '\'' && iter.peek() == Some(&'\'') {
+                // doubled quote becomes just one quote
+                iter.next().unwrap()
+            } else {
+                c
+            };
+
+            result.push(newc);
+        }
+        Ok(result)
+    } else {
+        Ok(s.to_string())
+    }
+}
+
+#[test]
+fn test_postgresql_conf_escapes() -> Result<()> {
+    assert_eq!(escape_str("foo bar"), "'foo bar'");
+    // these don't need to be quoted
+    assert_eq!(escape_str("foo"), "foo");
+    assert_eq!(escape_str("123"), "123");
+    assert_eq!(escape_str("+123"), "+123");
+    assert_eq!(escape_str("-10"), "-10");
+    assert_eq!(escape_str("1foo"), "1foo");
+    assert_eq!(escape_str("foo1"), "foo1");
+    assert_eq!(escape_str("10MB"), "10MB");
+    assert_eq!(escape_str("-10kB"), "-10kB");
+
+    // these need quoting and/or escaping
+    assert_eq!(escape_str("foo bar"), "'foo bar'");
+    assert_eq!(escape_str("fo'o"), "'fo''o'");
+    assert_eq!(escape_str("fo\no"), "'fo\\no'");
+    assert_eq!(escape_str("fo\\o"), "'fo\\\\o'");
+    assert_eq!(escape_str("10 cats"), "'10 cats'");
+
+    // Test de-escaping
+    assert_eq!(deescape_str(&escape_str("foo"))?, "foo");
+    assert_eq!(deescape_str(&escape_str("fo'o\nba\\r"))?, "fo'o\nba\\r");
+    assert_eq!(deescape_str("'\\b\\f\\n\\r\\t'")?, "\x08\x0c\n\r\t");
+
+    // octal-escapes are currently not supported
+    assert!(deescape_str("'foo\\7\\07\\007'").is_err());
+
+    Ok(())
+}

control_plane/src/safekeeper.rs

@@ -0,0 +1,277 @@
+use std::io::Write;
+use std::net::TcpStream;
+use std::path::PathBuf;
+use std::process::Command;
+use std::sync::Arc;
+use std::time::Duration;
+use std::{io, result, thread};
+
+use anyhow::bail;
+use nix::errno::Errno;
+use nix::sys::signal::{kill, Signal};
+use nix::unistd::Pid;
+use postgres::Config;
+use reqwest::blocking::{Client, RequestBuilder, Response};
+use reqwest::{IntoUrl, Method};
+use thiserror::Error;
+use zenith_utils::http::error::HttpErrorBody;
+use zenith_utils::postgres_backend::AuthType;
+
+use crate::local_env::{LocalEnv, SafekeeperConf};
+use crate::read_pidfile;
+use crate::storage::PageServerNode;
+use zenith_utils::connstring::connection_address;
+use zenith_utils::connstring::connection_host_port;
+
+#[derive(Error, Debug)]
+pub enum SafekeeperHttpError {
+    #[error("Reqwest error: {0}")]
+    Transport(#[from] reqwest::Error),
+
+    #[error("Error: {0}")]
+    Response(String),
+}
+
+type Result<T> = result::Result<T, SafekeeperHttpError>;
+
+pub trait ResponseErrorMessageExt: Sized {
+    fn error_from_body(self) -> Result<Self>;
+}
+
+impl ResponseErrorMessageExt for Response {
+    fn error_from_body(self) -> Result<Self> {
+        let status = self.status();
+        if !(status.is_client_error() || status.is_server_error()) {
+            return Ok(self);
+        }
+
+        // reqwest do not export it's error construction utility functions, so lets craft the message ourselves
+        let url = self.url().to_owned();
+        Err(SafekeeperHttpError::Response(
+            match self.json::<HttpErrorBody>() {
+                Ok(err_body) => format!("Error: {}", err_body.msg),
+                Err(_) => format!("Http error ({}) at {}.", status.as_u16(), url),
+            },
+        ))
+    }
+}
+
+//
+// Control routines for safekeeper.
+//
+// Used in CLI and tests.
+//
+#[derive(Debug)]
+pub struct SafekeeperNode {
+    pub name: String,
+
+    pub conf: SafekeeperConf,
+
+    pub pg_connection_config: Config,
+    pub env: LocalEnv,
+    pub http_client: Client,
+    pub http_base_url: String,
+
+    pub pageserver: Arc<PageServerNode>,
+}
+
+impl SafekeeperNode {
+    pub fn from_env(env: &LocalEnv, conf: &SafekeeperConf) -> SafekeeperNode {
+        let pageserver = Arc::new(PageServerNode::from_env(env));
+
+        println!("initializing for {} for {}", conf.name, conf.http_port);
+
+        SafekeeperNode {
+            name: conf.name.clone(),
+            conf: conf.clone(),
+            pg_connection_config: Self::safekeeper_connection_config(conf.pg_port),
+            env: env.clone(),
+            http_client: Client::new(),
+            http_base_url: format!("http://localhost:{}/v1", conf.http_port),
+            pageserver,
+        }
+    }
+
+    /// Construct libpq connection string for connecting to this safekeeper.
+    fn safekeeper_connection_config(port: u16) -> Config {
+        // TODO safekeeper authentication not implemented yet
+        format!("postgresql://no_user@localhost:{}/no_db", port)
+            .parse()
+            .unwrap()
+    }
+
+    pub fn datadir_path(&self) -> PathBuf {
+        self.env.safekeeper_data_dir(&self.name)
+    }
+
+    pub fn pid_file(&self) -> PathBuf {
+        self.datadir_path().join("safekeeper.pid")
+    }
+
+    pub fn start(&self) -> anyhow::Result<()> {
+        print!(
+            "Starting safekeeper at '{}' in '{}'",
+            connection_address(&self.pg_connection_config),
+            self.datadir_path().display()
+        );
+        io::stdout().flush().unwrap();
+
+        // Configure connection to page server
+        //
+        // FIXME: We extract the host and port from the connection string instead of using
+        // the connection string directly, because the 'safekeeper' binary expects
+        // host:port format. That's a bit silly when we already have a full libpq connection
+        // string at hand.
+        let pageserver_conn = {
+            let (host, port) = connection_host_port(&self.pageserver.pg_connection_config);
+            format!("{}:{}", host, port)
+        };
+
+        let listen_pg = format!("localhost:{}", self.conf.pg_port);
+        let listen_http = format!("localhost:{}", self.conf.http_port);
+
+        let mut cmd: &mut Command = &mut Command::new(self.env.safekeeper_bin()?);
+        cmd = cmd
+            .args(&["-D", self.datadir_path().to_str().unwrap()])
+            .args(&["--listen-pg", &listen_pg])
+            .args(&["--listen-http", &listen_http])
+            .args(&["--pageserver", &pageserver_conn])
+            .args(&["--recall", "1 second"])
+            .arg("--daemonize")
+            .env_clear()
+            .env("RUST_BACKTRACE", "1");
+        if !self.conf.sync {
+            cmd = cmd.arg("--no-sync");
+        }
+
+        if self.env.pageserver.auth_type == AuthType::ZenithJWT {
+            cmd.env("PAGESERVER_AUTH_TOKEN", &self.env.pageserver.auth_token);
+        }
+
+        if !cmd.status()?.success() {
+            bail!(
+                "Safekeeper failed to start. See '{}' for details.",
+                self.datadir_path().join("safekeeper.log").display()
+            );
+        }
+
+        // It takes a while for the safekeeper to start up. Wait until it is
+        // open for business.
+        const RETRIES: i8 = 15;
+        for retries in 1..RETRIES {
+            match self.check_status() {
+                Ok(_) => {
+                    println!("\nSafekeeper started");
+                    return Ok(());
+                }
+                Err(err) => {
+                    match err {
+                        SafekeeperHttpError::Transport(err) => {
+                            if err.is_connect() && retries < 5 {
+                                print!(".");
+                                io::stdout().flush().unwrap();
+                            } else {
+                                if retries == 5 {
+                                    println!() // put a line break after dots for second message
+                                }
+                                println!(
+                                    "Safekeeper not responding yet, err {} retrying ({})...",
+                                    err, retries
+                                );
+                            }
+                        }
+                        SafekeeperHttpError::Response(msg) => {
+                            bail!("safekeeper failed to start: {} ", msg)
+                        }
+                    }
+                    thread::sleep(Duration::from_secs(1));
+                }
+            }
+        }
+        bail!("safekeeper failed to start in {} seconds", RETRIES);
+    }
+
+    ///
+    /// Stop the server.
+    ///
+    /// If 'immediate' is true, we use SIGQUIT, killing the process immediately.
+    /// Otherwise we use SIGTERM, triggering a clean shutdown
+    ///
+    /// If the server is not running, returns success
+    ///
+    pub fn stop(&self, immediate: bool) -> anyhow::Result<()> {
+        let pid_file = self.pid_file();
+        if !pid_file.exists() {
+            println!("Safekeeper {} is already stopped", self.name);
+            return Ok(());
+        }
+        let pid = read_pidfile(&pid_file)?;
+        let pid = Pid::from_raw(pid);
+
+        let sig = if immediate {
+            println!("Stop safekeeper immediately");
+            Signal::SIGQUIT
+        } else {
+            println!("Stop safekeeper gracefully");
+            Signal::SIGTERM
+        };
+        match kill(pid, sig) {
+            Ok(_) => (),
+            Err(Errno::ESRCH) => {
+                println!(
+                    "Safekeeper with pid {} does not exist, but a PID file was found",
+                    pid
+                );
+                return Ok(());
+            }
+            Err(err) => bail!(
+                "Failed to send signal to safekeeper with pid {}: {}",
+                pid,
+                err.desc()
+            ),
+        }
+
+        let address = connection_address(&self.pg_connection_config);
+
+        // TODO Remove this "timeout" and handle it on caller side instead.
+        // Shutting down may take a long time,
+        // if safekeeper flushes a lot of data
+        for _ in 0..100 {
+            if let Err(_e) = TcpStream::connect(&address) {
+                println!("Safekeeper stopped receiving connections");
+
+                //Now check status
+                match self.check_status() {
+                    Ok(_) => {
+                        println!("Safekeeper status is OK. Wait a bit.");
+                        thread::sleep(Duration::from_secs(1));
+                    }
+                    Err(err) => {
+                        println!("Safekeeper status is: {}", err);
+                        return Ok(());
+                    }
+                }
+            } else {
+                println!("Safekeeper still receives connections");
+                thread::sleep(Duration::from_secs(1));
+            }
+        }
+
+        bail!("Failed to stop safekeeper with pid {}", pid);
+    }
+
+    fn http_request<U: IntoUrl>(&self, method: Method, url: U) -> RequestBuilder {
+        // TODO: authentication
+        //if self.env.auth_type == AuthType::ZenithJWT {
+        //    builder = builder.bearer_auth(&self.env.safekeeper_auth_token)
+        //}
+        self.http_client.request(method, url)
+    }
+
+    pub fn check_status(&self) -> Result<()> {
+        self.http_request(Method::GET, format!("{}/{}", self.http_base_url, "status"))
+            .send()?
+            .error_from_body()?;
+        Ok(())
+    }
+}

control_plane/src/storage.rs

@@ -1,22 +1,62 @@
-use std::collections::HashMap;
+use std::io::Write;
 use std::net::TcpStream;
 use std::path::PathBuf;
 use std::process::Command;
-use std::thread;
 use std::time::Duration;
+use std::{io, result, thread};
 
-use anyhow::{anyhow, bail, Result};
+use anyhow::{anyhow, bail};
+use nix::errno::Errno;
 use nix::sys::signal::{kill, Signal};
 use nix::unistd::Pid;
+use pageserver::http::models::{BranchCreateRequest, TenantCreateRequest};
 use postgres::{Config, NoTls};
+use reqwest::blocking::{Client, RequestBuilder, Response};
+use reqwest::{IntoUrl, Method};
+use thiserror::Error;
+use zenith_utils::http::error::HttpErrorBody;
 use zenith_utils::postgres_backend::AuthType;
 use zenith_utils::zid::ZTenantId;
 
 use crate::local_env::LocalEnv;
 use crate::read_pidfile;
 use pageserver::branches::BranchInfo;
+use pageserver::tenant_mgr::TenantInfo;
 use zenith_utils::connstring::connection_address;
 
+#[derive(Error, Debug)]
+pub enum PageserverHttpError {
+    #[error("Reqwest error: {0}")]
+    Transport(#[from] reqwest::Error),
+
+    #[error("Error: {0}")]
+    Response(String),
+}
+
+type Result<T> = result::Result<T, PageserverHttpError>;
+
+pub trait ResponseErrorMessageExt: Sized {
+    fn error_from_body(self) -> Result<Self>;
+}
+
+impl ResponseErrorMessageExt for Response {
+    fn error_from_body(self) -> Result<Self> {
+        let status = self.status();
+        if !(status.is_client_error() || status.is_server_error()) {
+            return Ok(self);
+        }
+
+        // reqwest do not export it's error construction utility functions, so lets craft the message ourselves
+        let url = self.url().to_owned();
+        Err(PageserverHttpError::Response(
+            match self.json::<HttpErrorBody>() {
+                Ok(err_body) => format!("Error: {}", err_body.msg),
+                Err(_) => format!("Http error ({}) at {}.", status.as_u16(), url),
+            },
+        ))
+    }
+}
+
 //
 // Control routines for pageserver.
 //
@@ -24,57 +64,64 @@ use zenith_utils::connstring::connection_address;
 //
 #[derive(Debug)]
 pub struct PageServerNode {
-    pub kill_on_exit: bool,
-    pub connection_config: Config,
+    pub pg_connection_config: Config,
     pub env: LocalEnv,
+    pub http_client: Client,
+    pub http_base_url: String,
 }
 
 impl PageServerNode {
     pub fn from_env(env: &LocalEnv) -> PageServerNode {
-        let password = if matches!(env.auth_type, AuthType::ZenithJWT) {
-            &env.auth_token
+        let password = if env.pageserver.auth_type == AuthType::ZenithJWT {
+            &env.pageserver.auth_token
         } else {
             ""
         };
 
         PageServerNode {
-            kill_on_exit: false,
-            connection_config: Self::default_config(password), // default
+            pg_connection_config: Self::pageserver_connection_config(
+                password,
+                env.pageserver.pg_port,
+            ),
             env: env.clone(),
+            http_client: Client::new(),
+            http_base_url: format!("http://localhost:{}/v1", env.pageserver.http_port),
         }
     }
 
-    fn default_config(password: &str) -> Config {
-        format!("postgresql://no_user:{}@localhost:64000/no_db", password)
+    /// Construct libpq connection string for connecting to the pageserver.
+    fn pageserver_connection_config(password: &str, port: u16) -> Config {
+        format!("postgresql://no_user:{}@localhost:{}/no_db", password, port)
             .parse()
             .unwrap()
     }
 
-    pub fn init(
-        &self,
-        create_tenant: Option<&str>,
-        enable_auth: bool,
-        repository_format: Option<&str>,
-    ) -> Result<()> {
+    pub fn init(&self, create_tenant: Option<&str>) -> anyhow::Result<()> {
         let mut cmd = Command::new(self.env.pageserver_bin()?);
+        let listen_pg = format!("localhost:{}", self.env.pageserver.pg_port);
+        let listen_http = format!("localhost:{}", self.env.pageserver.http_port);
         let mut args = vec![
             "--init",
             "-D",
             self.env.base_data_dir.to_str().unwrap(),
             "--postgres-distrib",
             self.env.pg_distrib_dir.to_str().unwrap(),
+            "--listen-pg",
+            &listen_pg,
+            "--listen-http",
+            &listen_http,
         ];
 
-        if enable_auth {
+        let auth_type_str = &self.env.pageserver.auth_type.to_string();
+        if self.env.pageserver.auth_type != AuthType::Trust {
             args.extend(&["--auth-validation-public-key-path", "auth_public_key.pem"]);
-            args.extend(&["--auth-type", "ZenithJWT"]);
+        }
+        args.extend(&["--auth-type", auth_type_str]);
+
+        if let Some(tenantid) = create_tenant {
+            args.extend(&["--create-tenant", tenantid])
         }
 
-        if let Some(repo_format) = repository_format {
-            args.extend(&["--repository-format", repo_format]);
-        }
-
-        create_tenant.map(|tenantid| args.extend(&["--create-tenant", tenantid]));
         let status = cmd
             .args(args)
             .env_clear()
@@ -97,16 +144,17 @@ impl PageServerNode {
         self.repo_path().join("pageserver.pid")
     }
 
-    pub fn start(&self) -> Result<()> {
-        println!(
-            "Starting pageserver at '{}' in {}",
-            connection_address(&self.connection_config),
+    pub fn start(&self) -> anyhow::Result<()> {
+        print!(
+            "Starting pageserver at '{}' in '{}'",
+            connection_address(&self.pg_connection_config),
             self.repo_path().display()
         );
+        io::stdout().flush().unwrap();
 
         let mut cmd = Command::new(self.env.pageserver_bin()?);
         cmd.args(&["-D", self.repo_path().to_str().unwrap()])
-            .arg("-d")
+            .arg("--daemonize")
             .env_clear()
             .env("RUST_BACKTRACE", "1");
 
@@ -119,91 +167,162 @@ impl PageServerNode {
 
         // It takes a while for the page server to start up. Wait until it is
         // open for business.
-        for retries in 1..15 {
-            match self.page_server_psql_client() {
+        const RETRIES: i8 = 15;
+        for retries in 1..RETRIES {
+            match self.check_status() {
                 Ok(_) => {
-                    println!("Pageserver started");
+                    println!("\nPageserver started");
                     return Ok(());
                 }
                 Err(err) => {
-                    println!(
-                        "Pageserver not responding yet, err {} retrying ({})...",
-                        err, retries
-                    );
+                    match err {
+                        PageserverHttpError::Transport(err) => {
+                            if err.is_connect() && retries < 5 {
+                                print!(".");
+                                io::stdout().flush().unwrap();
+                            } else {
+                                if retries == 5 {
+                                    println!() // put a line break after dots for second message
+                                }
+                                println!(
+                                    "Pageserver not responding yet, err {} retrying ({})...",
+                                    err, retries
+                                );
+                            }
+                        }
+                        PageserverHttpError::Response(msg) => {
+                            bail!("pageserver failed to start: {} ", msg)
+                        }
+                    }
                     thread::sleep(Duration::from_secs(1));
                 }
             }
         }
-        bail!("pageserver failed to start");
+        bail!("pageserver failed to start in {} seconds", RETRIES);
     }
 
-    pub fn stop(&self) -> Result<()> {
-        let pid = read_pidfile(&self.pid_file())?;
-        let pid = Pid::from_raw(pid);
-        if kill(pid, Signal::SIGTERM).is_err() {
-            bail!("Failed to kill pageserver with pid {}", pid);
+    ///
+    /// Stop the server.
+    ///
+    /// If 'immediate' is true, we use SIGQUIT, killing the process immediately.
+    /// Otherwise we use SIGTERM, triggering a clean shutdown
+    ///
+    /// If the server is not running, returns success
+    ///
+    pub fn stop(&self, immediate: bool) -> anyhow::Result<()> {
+        let pid_file = self.pid_file();
+        if !pid_file.exists() {
+            println!("Pageserver is already stopped");
+            return Ok(());
         }
+        let pid = Pid::from_raw(read_pidfile(&pid_file)?);
 
-        // wait for pageserver stop
-        let address = connection_address(&self.connection_config);
-        for _ in 0..5 {
-            let stream = TcpStream::connect(&address);
-            thread::sleep(Duration::from_secs(1));
-            if let Err(_e) = stream {
-                println!("Pageserver stopped");
+        let sig = if immediate {
+            println!("Stop pageserver immediately");
+            Signal::SIGQUIT
+        } else {
+            println!("Stop pageserver gracefully");
+            Signal::SIGTERM
+        };
+        match kill(pid, sig) {
+            Ok(_) => (),
+            Err(Errno::ESRCH) => {
+                println!(
+                    "Pageserver with pid {} does not exist, but a PID file was found",
+                    pid
+                );
                 return Ok(());
             }
-            println!("Stopping pageserver on {}", address);
+            Err(err) => bail!(
+                "Failed to send signal to pageserver with pid {}: {}",
+                pid,
+                err.desc()
+            ),
+        }
+
+        let address = connection_address(&self.pg_connection_config);
+
+        // TODO Remove this "timeout" and handle it on caller side instead.
+        // Shutting down may take a long time,
+        // if pageserver checkpoints a lot of data
+        for _ in 0..100 {
+            if let Err(_e) = TcpStream::connect(&address) {
+                println!("Pageserver stopped receiving connections");
+
+                //Now check status
+                match self.check_status() {
+                    Ok(_) => {
+                        println!("Pageserver status is OK. Wait a bit.");
+                        thread::sleep(Duration::from_secs(1));
+                    }
+                    Err(err) => {
+                        println!("Pageserver status is: {}", err);
+                        return Ok(());
+                    }
+                }
+            } else {
+                println!("Pageserver still receives connections");
+                thread::sleep(Duration::from_secs(1));
+            }
         }
 
         bail!("Failed to stop pageserver with pid {}", pid);
     }
 
     pub fn page_server_psql(&self, sql: &str) -> Vec<postgres::SimpleQueryMessage> {
-        let mut client = self.connection_config.connect(NoTls).unwrap();
+        let mut client = self.pg_connection_config.connect(NoTls).unwrap();
 
         println!("Pageserver query: '{}'", sql);
         client.simple_query(sql).unwrap()
     }
 
-    pub fn page_server_psql_client(&self) -> Result<postgres::Client, postgres::Error> {
-        self.connection_config.connect(NoTls)
+    pub fn page_server_psql_client(&self) -> result::Result<postgres::Client, postgres::Error> {
+        self.pg_connection_config.connect(NoTls)
     }
 
-    pub fn tenants_list(&self) -> Result<Vec<String>> {
-        let mut client = self.page_server_psql_client()?;
-        let query_result = client.simple_query("tenant_list")?;
-        let tenants_json = query_result
-            .first()
-            .map(|msg| match msg {
-                postgres::SimpleQueryMessage::Row(row) => row.get(0),
-                _ => None,
-            })
-            .flatten()
-            .ok_or_else(|| anyhow!("missing tenants"))?;
-
-        Ok(serde_json::from_str(tenants_json)?)
+    fn http_request<U: IntoUrl>(&self, method: Method, url: U) -> RequestBuilder {
+        let mut builder = self.http_client.request(method, url);
+        if self.env.pageserver.auth_type == AuthType::ZenithJWT {
+            builder = builder.bearer_auth(&self.env.pageserver.auth_token)
+        }
+        builder
     }
 
-    pub fn tenant_create(&self, tenantid: &ZTenantId) -> Result<()> {
-        let mut client = self.page_server_psql_client()?;
-        client.simple_query(format!("tenant_create {}", tenantid).as_str())?;
+    pub fn check_status(&self) -> Result<()> {
+        self.http_request(Method::GET, format!("{}/{}", self.http_base_url, "status"))
+            .send()?
+            .error_from_body()?;
         Ok(())
     }
 
-    pub fn branches_list(&self, tenantid: &ZTenantId) -> Result<Vec<BranchInfo>> {
-        let mut client = self.page_server_psql_client()?;
-        let query_result = client.simple_query(&format!("branch_list {}", tenantid))?;
-        let branches_json = query_result
-            .first()
-            .map(|msg| match msg {
-                postgres::SimpleQueryMessage::Row(row) => row.get(0),
-                _ => None,
-            })
-            .flatten()
-            .ok_or_else(|| anyhow!("missing branches"))?;
+    pub fn tenant_list(&self) -> Result<Vec<TenantInfo>> {
+        Ok(self
+            .http_request(Method::GET, format!("{}/{}", self.http_base_url, "tenant"))
+            .send()?
+            .error_from_body()?
+            .json()?)
+    }
 
-        Ok(serde_json::from_str(branches_json)?)
+    pub fn tenant_create(&self, tenantid: ZTenantId) -> Result<()> {
+        Ok(self
+            .http_request(Method::POST, format!("{}/{}", self.http_base_url, "tenant"))
+            .json(&TenantCreateRequest {
+                tenant_id: tenantid,
+            })
+            .send()?
+            .error_from_body()?
+            .json()?)
+    }
+
+    pub fn branch_list(&self, tenantid: &ZTenantId) -> Result<Vec<BranchInfo>> {
+        Ok(self
+            .http_request(
+                Method::GET,
+                format!("{}/branch/{}", self.http_base_url, tenantid),
+            )
+            .send()?
+            .error_from_body()?
+            .json()?)
     }
 
     pub fn branch_create(
@@ -212,56 +331,30 @@ impl PageServerNode {
         startpoint: &str,
         tenantid: &ZTenantId,
     ) -> Result<BranchInfo> {
-        let mut client = self.page_server_psql_client()?;
-        let query_result = client.simple_query(
-            format!("branch_create {} {} {}", tenantid, branch_name, startpoint).as_str(),
-        )?;
-
-        let branch_json = query_result
-            .first()
-            .map(|msg| match msg {
-                postgres::SimpleQueryMessage::Row(row) => row.get(0),
-                _ => None,
+        Ok(self
+            .http_request(Method::POST, format!("{}/branch", self.http_base_url))
+            .json(&BranchCreateRequest {
+                tenant_id: tenantid.to_owned(),
+                name: branch_name.to_owned(),
+                start_point: startpoint.to_owned(),
             })
-            .flatten()
-            .ok_or_else(|| anyhow!("missing branch"))?;
-
-        let res: BranchInfo = serde_json::from_str(branch_json).map_err(|e| {
-            anyhow!(
-                "failed to parse branch_create response: {}: {}",
-                branch_json,
-                e
-            )
-        })?;
-
-        Ok(res)
+            .send()?
+            .error_from_body()?
+            .json()?)
     }
 
-    // TODO: make this a separate request type and avoid loading all the branches
     pub fn branch_get_by_name(
         &self,
         tenantid: &ZTenantId,
         branch_name: &str,
     ) -> Result<BranchInfo> {
-        let branch_infos = self.branches_list(tenantid)?;
-        let branche_by_name: Result<HashMap<String, BranchInfo>> = branch_infos
-            .into_iter()
-            .map(|branch_info| Ok((branch_info.name.clone(), branch_info)))
-            .collect();
-        let branche_by_name = branche_by_name?;
-
-        let branch = branche_by_name
-            .get(branch_name)
-            .ok_or_else(|| anyhow!("Branch {} not found", branch_name))?;
-
-        Ok(branch.clone())
-    }
-}
-
-impl Drop for PageServerNode {
-    fn drop(&mut self) {
-        if self.kill_on_exit {
-            let _ = self.stop();
-        }
+        Ok(self
+            .http_request(
+                Method::GET,
+                format!("{}/branch/{}/{}", self.http_base_url, tenantid, branch_name),
+            )
+            .send()?
+            .error_for_status()?
+            .json()?)
     }
 }

docker-entrypoint.sh

@@ -1,11 +1,13 @@
 #!/bin/sh
+set -eux
+
 if [ "$1" = 'pageserver' ]; then
     if [ ! -d "/data/tenants" ]; then
         echo "Initializing pageserver data directory"
         pageserver --init -D /data --postgres-distrib /usr/local
     fi
     echo "Staring pageserver at 0.0.0.0:6400"
-    pageserver -l 0.0.0.0:6400 -D /data
+    pageserver -l 0.0.0.0:6400 --listen-http 0.0.0.0:9898 -D /data
 else
     "$@"
 fi

docs/README.md

@@ -4,8 +4,11 @@
 
 - [authentication.md](authentication.md) — pageserver JWT authentication.
 - [docker.md](docker.md) — Docker images and building pipeline.
+- [glossary.md](glossary.md) — Glossary of all the terms used in codebase.
 - [multitenancy.md](multitenancy.md) — how multitenancy is organized in the pageserver and Zenith CLI.
+- [sourcetree.md](sourcetree.md) — Overview of the source tree layeout.
 - [pageserver/README](/pageserver/README) — pageserver overview.
 - [postgres_ffi/README](/postgres_ffi/README) — Postgres FFI overview.
 - [test_runner/README.md](/test_runner/README.md) — tests infrastructure overview.
-- [walkeeper/README](/walkeeper/README.md) — WAL service overview.
+- [walkeeper/README](/walkeeper/README) — WAL service overview.
+- [core_changes.md](core_changes.md) - Description of Zenith changes in Postgres core

docs/core_changes.md

@@ -0,0 +1,202 @@
+1. Add t_cid to XLOG record
+- Why?
+  The cmin/cmax on a heap page is a real bummer. I don't see any other way to fix that than bite the bullet and modify the WAL-logging routine to include the cmin/cmax.
+
+  To recap, the problem is that the XLOG_HEAP_INSERT record does not include the command id of the inserted row. And same with deletion/update. So in the primary, a row is inserted with current xmin + cmin. But in the replica, the cmin is always set to 1. That works, because the command id is only relevant to the inserting transaction itself. After commit/abort, no one cares abut it anymore.
+
+- Alternatives?
+  I don't know
+
+2. Add PD_WAL_LOGGED.
+- Why?
+  Postgres sometimes writes data to the page before it is wal-logged. If such page ais swapped out, we  will loose this change. The problem is currently solved by setting PD_WAL_LOGGED bit in page header. When page without this bit set is written to the SMGR, then it is forced to be written to the WAL as FPI using log_newpage_copy() function.
+
+  There was wrong assumption that it can happen only during construction of some exotic indexes (like gist). It is not true. The same situation can happen with COPY,VACUUM and when record hint bits are set.
+
+- Discussion:
+  https://discord.com/channels/869525774699462656/882681420986851359
+
+- Alternatives:
+  Do not store this flag in page header, but associate this bit with shared buffer. Logically it is more correct but in practice we will get not advantages: neither in space, neither in CPU overhead.
+
+
+3. XLogReadBufferForRedo not always loads and pins requested buffer. So we need to add extra checks that buffer is really pinned. Also do not use BufferGetBlockNumber for buffer returned by XLogReadBufferForRedo.
+- Why?
+  XLogReadBufferForRedo is not pinning pages which are not requested by wal-redo. It is specific only for wal-redo Postgres.
+
+- Alternatives?
+  No
+
+
+4. Eliminate reporting of some warnings related with hint bits, for example
+"page is not marked all-visible but visibility map bit is set in relation".
+- Why?
+  Hint bit may be not WAL logged.
+
+- Alternative?
+  Always wal log any page changes.
+
+
+5. Maintain last written LSN.
+- Why?
+  When compute node requests page from page server, we need to specify LSN. Ideally it should be LSN
+  of WAL record performing last update of this pages. But we do not know it, because we do not have page.
+  We can use current WAL flush position, but in this case there is high probability that page server
+  will be blocked until this peace of WAL is delivered.
+  As better approximation we can keep max LSN of written page. It will be better to take in account LSNs only of evicted pages,
+  but SMGR API doesn't provide such knowledge.
+
+- Alternatives?
+  Maintain map of LSNs of evicted pages.
+
+
+6. Launching Postgres without WAL.
+- Why?
+  According to Zenith architecture compute node is stateless. So when we are launching
+  compute node, we need to provide some dummy PG_DATADIR. Relation pages
+  can be requested on demand from page server. But Postgres still need some non-relational data:
+  control and configuration files, SLRUs,...
+  It is currently implemented  using basebackup (do not mix with pg_basebackup) which is created
+  by pageserver. It includes in this tarball config/control files, SLRUs and required directories.
+  As far as pageserver do not have original (non-scattered) WAL segments, it includes in
+  this tarball dummy WAL segment which contains only SHUTDOWN_CHECKPOINT record at the beginning of segment,
+  which redo field points to the end of wal. It allows to load checkpoint record in more or less
+  standard way with minimal changes of Postgres, but then some special handling is needed,
+  including restoring previous record position from zenith.signal file.
+  Also we have to correctly initialize header of last WAL page (pointed by checkpoint.redo)
+  to pass checks performed by XLogReader.
+
+- Alternatives?
+  We may not include fake WAL segment in tarball at all and modify xlog.c to load checkpoint record
+  in special way. But it may only increase number of changes in xlog.c
+
+7. Add redo_read_buffer_filter callback to XLogReadBufferForRedoExtended
+- Why?
+  We need a way in wal-redo Postgres to ignore pages which are not requested by pageserver.
+  So wal-redo Postgres reconstructs only requested page and for all other returns BLK_DONE
+  which means that recovery for them is not needed.
+
+- Alternatives?
+  No
+
+8. Enforce WAL logging of sequence updates.
+- Why?
+  Due to performance reasons Postgres don't want to log each fetching of a value from a sequence,
+  so we pre-log a few fetches in advance. In the event of crash we can lose
+  (skip over) as many values as we pre-logged.
+  But it doesn't work with Zenith because page with sequence value can be evicted from buffer cache
+  and we will get a gap in sequence values even without crash.
+
+- Alternatives:
+  Do not try to preserve sequential order but avoid performance penalty.
+
+
+9. Treat unlogged tables as normal (permanent) tables.
+- Why?
+  Unlogged tables are not transient, so them have to survive node restart (unlike temporary tables).
+  But as far as compute node is stateless, we need to persist their data to storage node.
+  And it can only be done through the WAL.
+
+- Alternatives?
+  * Store unlogged tables locally (violates requirement of stateless compute nodes).
+  * Prohibit unlogged tables at all.
+
+
+10. Support start Postgres in wal-redo mode
+- Why?
+  To be able to apply WAL record and reconstruct pages at page server.
+
+- Alternatives?
+  * Rewrite redo handlers in Rust
+  * Do not reconstruct pages at page server at all and do it at compute node.
+
+
+11. WAL proposer
+- Why?
+  WAL proposer is communicating with safekeeper and ensures WAL durability by quorum writes.
+  It is currently implemented as patch to standard WAL sender.
+
+- Alternatives?
+  Can be moved to extension if some extra callbacks will be added to wal sender code.
+
+
+12. Secure Computing BPF API wrapper.
+- Why?
+  Pageserver delegates complex WAL decoding duties to Postgres,
+  which means that the latter might fall victim to carefully designed
+  malicious WAL records and start doing harmful things to the system.
+  To prevent this, it has been decided to limit possible interactions
+  with the outside world using the Secure Computing BPF mode.
+
+- Alternatives:
+  * Rewrite redo handlers in Rust.
+  * Add more checks to guarantee correctness of WAL records.
+  * Move seccomp.c to extension
+  * Many other discussed approaches to neutralize incorrect WAL records vulnerabilities.
+
+
+13. Callbacks for replica feedbacks
+- Why?
+  Allowing waproposer to interact with walsender code.
+
+- Alternatives
+  Copy walsender code to walproposer.
+
+
+14. Support multiple SMGR implementations.
+- Why?
+  Postgres provides abstract API for storage manager but it has only one implementation
+  and provides no way to replace it with custom storage manager.
+
+- Alternatives?
+  None.
+
+
+15. Calculate database size as sum of all database relations.
+- Why?
+  Postgres is calculating database size by traversing data directory
+  but as far as Zenith compute node is stateless we can not do it.
+
+- Alternatives?
+  Send this request directly to pageserver and calculate real (physical) size
+  of Zenith representation of database/timeline, rather than sum logical size of all relations.
+
+
+-----------------------------------------------
+Not currently committed but proposed:
+
+1. Disable ring buffer buffer manager strategies
+- Why?
+  Postgres tries to avoid cache flushing by bulk operations (copy, seqscan, vacuum,...).
+  Even if there are free space in buffer cache, pages may be evicted.
+  Negative effect of it can be somehow compensated by file system cache, but in case of Zenith
+  cost of requesting page from page server is much higher.
+
+- Alternatives?
+  Instead of just prohibiting ring buffer we may try to implement more flexible eviction policy,
+  for example copy evicted page from ring buffer to some other buffer if there is free space
+  in buffer cache.
+
+2. Disable marking page as dirty when hint bits are set.
+- Why?
+  Postgres has to modify page twice: first time when some tuple is updated and second time when
+  hint bits are set. Wal logging hint bits updates requires FPI which significantly increase size of WAL.
+
+- Alternatives?
+  Add special WAL record for setting page hints.
+
+3. Prefetching
+- Why?
+  As far as pages in Zenith are loaded on demand, to reduce node startup time
+  and also sppedup some massive queries we need some mechanism for bulk loading to
+  reduce page request round-trip overhead.
+
+  Currently Postgres is supporting prefetching only for bitmap scan.
+  In Zenith we also use prefetch for sequential and index scan. For sequential scan we prefetch
+  some number of following pages. For index scan we prefetch pages of heap relation addressed by TIDs.
+
+4. Prewarming.
+- Why?
+  Short downtime (or, in other words, fast compute node restart time) is one of the key feature of Zenith.
+  But overhead of request-response round-trip for loading pages on demand can make started node warm-up quite slow.
+  We can capture state of compute node buffer cache and send bulk request for this pages at startup.

docs/docker.md

@@ -4,7 +4,7 @@
 
 Currently we build two main images:
 
-- [zenithdb/zenith](https://hub.docker.com/repository/docker/zenithdb/zenith) — image with pre-built `pageserver`, `wal_acceptor` and `proxy` binaries and all the required runtime dependencies. Built from [/Dockerfile](/Dockerfile).
+- [zenithdb/zenith](https://hub.docker.com/repository/docker/zenithdb/zenith) — image with pre-built `pageserver`, `safekeeper` and `proxy` binaries and all the required runtime dependencies. Built from [/Dockerfile](/Dockerfile).
 - [zenithdb/compute-node](https://hub.docker.com/repository/docker/zenithdb/compute-node) — compute node image with pre-built Postgres binaries from [zenithdb/postgres](https://github.com/zenithdb/postgres).
 
 And two intermediate images used either to reduce build time or to deliver some additional binary tools from other repos:

docs/glossary.md

@@ -0,0 +1,218 @@
+# Glossary
+
+### Authentication
+
+### Base image (page image)
+
+### Basebackup
+
+A tarball with files needed to bootstrap a compute node[] and a corresponding command to create it.
+NOTE:It has nothing to do with PostgreSQL pg_basebackup.
+
+### Branch
+
+We can create branch at certain LSN using `zenith branch` command.
+Each Branch lives in a corresponding timeline[] and has an ancestor[].
+
+
+### Checkpoint (PostgreSQL)
+
+NOTE: This is an overloaded term.
+
+A checkpoint record in the WAL marks a point in the WAL sequence at which it is guaranteed that all data files have been updated with all information from shared memory modified before that checkpoint; 
+
+### Checkpoint (Layered repository)
+
+NOTE: This is an overloaded term.
+
+Whenever enough WAL has been accumulated in memory, the page server []
+writes out the changes from in-memory layers into new layer files[]. This process
+is called "checkpointing". The page server only creates layer files for
+relations that have been modified since the last checkpoint. 
+
+Configuration parameter `checkpoint_distance` defines the distance
+from current LSN to perform checkpoint of in-memory layers.
+Default is `DEFAULT_CHECKPOINT_DISTANCE`.
+Set this parameter to `0` to force checkpoint of every layer.
+
+Configuration parameter `checkpoint_period` defines the interval between checkpoint iterations.
+Default is `DEFAULT_CHECKPOINT_PERIOD`.
+### Compute node
+
+Stateless Postgres node that stores data in pageserver.
+
+### Garbage collection
+
+The process of removing old on-disk layers that are not needed by any timeline anymore.
+### Fork
+
+Each of the separate segmented file sets in which a relation is stored. The main fork is where the actual data resides. There also exist two secondary forks for metadata: the free space map and the visibility map.
+Each PostgreSQL fork is considered a separate relish.
+
+### Layer
+
+Each layer corresponds to the specific version of a relish Segment in a range of LSNs.
+There are two kinds of layers, in-memory and on-disk layers. In-memory
+layers are used to ingest incoming WAL, and provide fast access
+to the recent page versions. On-disk layers are stored as files on disk, and
+are immutable.
+### Layer file (on-disk layer)
+
+Layered repository on-disk format is based on immutable files.  The
+files are called "layer files". Each file corresponds to one RELISH_SEG_SIZE
+segment of a PostgreSQL relation fork. There are two kinds of layer
+files: image files and delta files. An image file contains a
+"snapshot" of the segment at a particular LSN, and a delta file
+contains WAL records applicable to the segment, in a range of LSNs.
+
+### Layer map
+
+The layer map tracks what layers exist for all the relishes in a timeline.
+### Layered repository
+
+Zenith repository implementation that keeps data in layers.
+### LSN
+
+
+### Page (block)
+
+The basic structure used to store relation data. All pages are of the same size.
+This is the unit of data exchange between compute node and pageserver.
+
+### Pageserver
+
+Zenith storage engine: repositories + wal receiver + page service + wal redo.
+
+### Page service
+
+The Page Service listens for GetPage@LSN requests from the Compute Nodes,
+and responds with pages from the repository.
+
+
+### PITR (Point-in-time-recovery)
+
+PostgreSQL's ability to restore up to a specified LSN.
+
+### Primary node
+
+
+### Proxy
+
+Postgres protocol proxy/router.
+This service listens psql port, can check auth via external service
+and create new databases and accounts (control plane API in our case).
+
+### Relation
+
+The generic term in PostgreSQL for all objects in a database that have a name and a list of attributes defined in a specific order.
+
+### Relish
+
+We call each relation and other file that is stored in the
+repository a "relish". It comes from "rel"-ish, as in "kind of a
+rel", because it covers relations as well as other things that are
+not relations, but are treated similarly for the purposes of the
+storage layer.
+
+### Replication slot
+
+
+### Replica node
+
+
+### Repository
+
+Repository stores multiple timelines, forked off from the same initial call to 'initdb'
+and has associated WAL redo service.
+One repository corresponds to one Tenant.
+
+### Retention policy
+
+How much history do we need to keep around for PITR and read-only nodes?
+
+### Segment (PostgreSQL)
+
+NOTE: This is an overloaded term.
+
+A physical file that stores data for a given relation. File segments are
+limited in size by a compile-time setting (1 gigabyte by default), so if a
+relation exceeds that size, it is split into multiple segments.
+
+### Segment (Layered Repository)
+
+NOTE: This is an overloaded term.
+
+Segment is a RELISH_SEG_SIZE slice of relish (identified by a SegmentTag).
+
+### SLRU
+
+SLRUs include pg_clog, pg_multixact/members, and
+pg_multixact/offsets. There are other SLRUs in PostgreSQL, but
+they don't need to be stored permanently (e.g. pg_subtrans),
+or we do not support them in zenith yet (pg_commit_ts).
+Each SLRU segment is considered a separate relish[].
+
+### Tenant (Multitenancy)
+Tenant represents a single customer, interacting with Zenith.
+Wal redo[] activity, timelines[], layers[] are managed for each tenant independently.
+One pageserver[] can serve multiple tenants at once.
+One safekeeper 
+
+See `docs/multitenancy.md` for more.
+
+### Timeline
+
+Timeline accepts page changes and serves get_page_at_lsn() and
+get_rel_size() requests. The term "timeline" is used internally
+in the system, but to users they are exposed as "branches", with
+human-friendly names.
+
+NOTE: this has nothing to do with PostgreSQL WAL timelines.
+
+### XLOG
+
+PostgreSQL alias for WAL[].
+
+### WAL (Write-ahead log)
+
+The journal that keeps track of the changes in the database cluster as user- and system-invoked operations take place. It comprises many individual WAL records[] written sequentially to WAL files[].
+
+### WAL acceptor, WAL proposer
+
+In the context of the consensus algorithm, the Postgres
+compute node is also known as the WAL proposer, and the safekeeper is also known
+as the acceptor. Those are the standard terms in the Paxos algorithm.
+
+### WAL receiver (WAL decoder)
+
+The WAL receiver connects to the external WAL safekeeping service (or
+directly to the primary) using PostgreSQL physical streaming
+replication, and continuously receives WAL. It decodes the WAL records,
+and stores them to the repository.
+
+We keep one WAL receiver active per timeline.
+
+### WAL record
+
+A low-level description of an individual data change.
+
+### WAL redo
+
+A service that runs PostgreSQL in a special wal_redo mode
+to apply given WAL records over an old page image and return new page image.
+
+### WAL safekeeper
+
+One node that participates in the quorum. All the safekeepers
+together form the WAL service.
+
+### WAL segment (WAL file)
+
+Also known as WAL segment or WAL segment file. Each of the sequentially-numbered files that provide storage space for WAL. The files are all of the same predefined size and are written in sequential order, interspersing changes as they occur in multiple simultaneous sessions.
+
+### WAL service
+
+The service as whole that ensures that WAL is stored durably.
+
+### Web console
+

docs/multitenancy.md

@@ -37,7 +37,7 @@ On the page server tenants introduce one level of indirection, so data directory
    ├── de182bc61fb11a5a6b390a8aed3a804a
    └── ee6016ec31116c1b7c33dfdfca38891f
 ```
-Wal redo activity, timelines, snapshots are managed for each tenant independently.
+Wal redo activity and timelines are managed for each tenant independently.
 
 For local environment used for example in tests there also new level of indirection for tenants. It touches `pgdatadirs` directory. Now it contains `tenants` subdirectory so the structure looks the following way:
 
@@ -56,4 +56,4 @@ Tenant id is passed to postgres via GUC the same way as the timeline. Tenant id
 
 ### Safety
 
-For now particular tenant can only appear on a particular pageserver. Set of WAL acceptors are also pinned to particular (tenantid, timeline) pair so there can only be one writer for particular (tenantid, timeline).
+For now particular tenant can only appear on a particular pageserver. Set of safekeepers are also pinned to particular (tenantid, timeline) pair so there can only be one writer for particular (tenantid, timeline).

docs/sourcetree.md

@@ -0,0 +1,81 @@
+## Source tree layout
+
+Below you will find a brief overview of each subdir in the source tree in alphabetical order.
+
+`/control_plane`:
+
+Local control plane.
+Functions to start, configure and stop pageserver and postgres instances running as a local processes.
+Intended to be used in integration tests and in CLI tools for local installations.
+
+`/docs`:
+
+Documentaion of the Zenith features and concepts.
+Now it is mostly dev documentation.
+
+`/monitoring`:
+
+TODO
+
+`/pageserver`:
+
+Zenith storage service.
+The pageserver has a few different duties:
+
+- Store and manage the data.
+- Generate a tarball with files needed to bootstrap ComputeNode.
+- Respond to GetPage@LSN requests from the Compute Nodes.
+- Receive WAL from the WAL service and decode it.
+- Replay WAL that's applicable to the chunks that the Page Server maintains
+
+For more detailed info, see `/pageserver/README`
+
+`/postgres_ffi`:
+
+Utility functions for interacting with PostgreSQL file formats.
+Misc constants, copied from PostgreSQL headers.
+
+`/proxy`:
+
+Postgres protocol proxy/router.
+This service listens psql port, can check auth via external service
+and create new databases and accounts (control plane API in our case).
+
+`/test_runner`:
+
+Integration tests, written in Python using the `pytest` framework.
+
+`/vendor/postgres`:
+
+PostgreSQL source tree, with the modifications needed for Zenith.
+
+`/vendor/postgres/contrib/zenith`:
+
+PostgreSQL extension that implements storage manager API and network communications with remote page server.
+
+`/vendor/postgres/contrib/zenith_test_utils`:
+
+PostgreSQL extension that contains functions needed for testing and debugging.
+
+`/walkeeper`:
+
+The zenith WAL service that receives WAL from a primary compute nodes and streams it to the pageserver.
+It acts as a holding area and redistribution center for recently generated WAL.
+
+For more detailed info, see `/walkeeper/README`
+
+`/workspace_hack`:
+The workspace_hack crate exists only to pin down some dependencies.
+
+`/zenith`
+
+Main entry point for the 'zenith' CLI utility.
+TODO: Doesn't it belong to control_plane?
+
+`/zenith_metrics`:
+
+Helpers for exposing Prometheus metrics from the server.
+
+`/zenith_utils`:
+
+Helpers that are shared between other crates in this repository.

pageserver/Cargo.toml

@@ -4,8 +4,6 @@ version = "0.1.0"
 authors = ["Stas Kelvich <stas@zenith.tech>"]
 edition = "2018"
 
-# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
-
 [dependencies]
 bookfile = "^0.3"
 chrono = "0.4.19"
@@ -14,37 +12,39 @@ regex = "1.4.5"
 bytes = { version = "1.0.1", features = ['serde'] }
 byteorder = "1.4.3"
 futures = "0.3.13"
+hyper = "0.14"
 lazy_static = "1.4.0"
-slog-stdlog = "4.1.0"
-slog-async = "2.6.0"
-slog-scope = "4.4.0"
-slog-term = "2.8.0"
-slog = "2.7.0"
 log = "0.4.14"
 clap = "2.33.0"
 daemonize = "0.4.1"
-rust-s3 = { version = "0.27.0-rc4", features = ["no-verify-ssl"] }
-tokio = { version = "1.5.0", features = ["full"] }
-tokio-stream = { version = "0.1.5" }
+tokio = { version = "1.11", features = ["process", "macros", "fs", "rt", "io-util"] }
 postgres-types = { git = "https://github.com/zenithdb/rust-postgres.git", rev="9eb0dbfbeb6a6c1b79099b9f7ae4a8c021877858" }
 postgres-protocol = { git = "https://github.com/zenithdb/rust-postgres.git", rev="9eb0dbfbeb6a6c1b79099b9f7ae4a8c021877858" }
 postgres = { git = "https://github.com/zenithdb/rust-postgres.git", rev="9eb0dbfbeb6a6c1b79099b9f7ae4a8c021877858" }
-# by default rust-rocksdb tries to build a lot of compression algos. Use lz4 only for now as it is simplest dependency.
-rocksdb = { version = "0.16.0", features = ["lz4"], default-features = false }
+routerify = "2"
 anyhow = "1.0"
 crc32c = "0.6.0"
-walkdir = "2"
 thiserror = "1.0"
-hex = "0.4.3"
+hex = { version = "0.4.3", features = ["serde"] }
 tar = "0.4.33"
 humantime = "2.1.0"
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1"
-fs_extra = "1.2.0"
 toml = "0.5"
 scopeguard = "1.1.0"
+rust-s3 = { version = "0.27.0-rc4", features = ["no-verify-ssl"] }
+async-trait = "0.1"
+const_format = "0.2.21"
+tracing = "0.1.27"
+signal-hook = {version = "0.3.10", features = ["extended-siginfo"] }
+url = "2"
+nix = "0.23"
 
 postgres_ffi = { path = "../postgres_ffi" }
 zenith_metrics = { path = "../zenith_metrics" }
 zenith_utils = { path = "../zenith_utils" }
 workspace_hack = { path = "../workspace_hack" }
+
+[dev-dependencies]
+hex-literal = "0.3"
+tempfile = "3.2"

pageserver/README

@@ -1,129 +0,0 @@
-## Page server architecture
-
-The Page Server is responsible for all operations on a number of
-"chunks" of relation data. A chunk corresponds to a PostgreSQL
-relation segment (i.e. one max. 1 GB file in the data directory), but
-it holds all the different versions of every page in the segment that
-are still needed by the system.
-
-Currently we do not specifically organize data in chunks.
-All page images and corresponding WAL records are stored as entries in a key-value storage,
-where StorageKey is a zenith_timeline_id + BufferTag + LSN.
-
-
-The Page Server has a few different duties:
-
-- Respond to GetPage@LSN requests from the Compute Nodes
-- Receive WAL from WAL safekeeper
-- Replay WAL that's applicable to the chunks that the Page Server maintains
-- Backup to S3
-
-
-The Page Server consists of multiple threads that operate on a shared
-cache of page versions:
-
-
-                                           | WAL
-                                           V
-                                   +--------------+
-                                   |              |
-                                   | WAL receiver |
-                                   |              |
-                                   +--------------+
-                                                                                 +----+
-                  +---------+                              ..........            |    |
-                  |         |                              .        .            |    |
- GetPage@LSN      |         |                              . backup .  ------->  | S3 |
-------------->    |  Page   |         page cache           .        .            |    |
-                  | Service |                              ..........            |    |
-   page           |         |                                                    +----+
-<-------------    |         |
-                  +---------+
-
-                             ...................................
-                             .                                 .
-                             . Garbage Collection / Compaction .
-                             ...................................
-
-Legend:
-
-+--+
-|  |   A thread or multi-threaded service
-+--+
-
-....
-.  .   Component that we will need, but doesn't exist at the moment. A TODO.
-....
-
---->   Data flow
-<---
-
-
-Page Service
-------------
-
-The Page Service listens for GetPage@LSN requests from the Compute Nodes,
-and responds with pages from the page cache.
-
-
-WAL Receiver
-------------
-
-The WAL receiver connects to the external WAL safekeeping service (or
-directly to the primary) using PostgreSQL physical streaming
-replication, and continuously receives WAL. It decodes the WAL records,
-and stores them to the page cache.
-
-
-Page Cache
-----------
-
-The Page Cache is a switchboard to access different Repositories.
-
-#### Repository
-Repository corresponds to one .zenith directory.
-Repository is needed to manage Timelines.
-
-#### Timeline
-Timeline is a page cache workhorse that accepts page changes
-and serves get_page_at_lsn() and get_rel_size() requests.
-Note: this has nothing to do with PostgreSQL WAL timeline.
-
-#### Branch
-We can create branch at certain LSN.
-Each Branch lives in a corresponding timeline and has an ancestor.
-
-To get full snapshot of data at certain moment we need to traverse timeline and its ancestors.
-
-#### ObjectRepository
-ObjectRepository implements Repository and has associated ObjectStore and WAL redo service.
-
-#### ObjectStore
-ObjectStore is an interface for key-value store for page images and wal records.
-Currently it has one implementation - RocksDB.
-
-#### WAL redo service
-WAL redo service - service that runs PostgreSQL in a special wal_redo mode
-to apply given WAL records over an old page image and return new page image.
-
-
-TODO: Garbage Collection / Compaction
--------------------------------------
-
-Periodically, the Garbage Collection / Compaction thread runs
-and applies pending WAL records, and removes old page versions that
-are no longer needed.
-
-
-TODO: Backup service
---------------------
-
-The backup service is responsible for periodically pushing the chunks to S3.
-
-TODO: How/when do restore from S3? Whenever we get a GetPage@LSN request for
-a chunk we don't currently have? Or when an external Control Plane tells us?
-
-TODO: Sharding
---------------------
-
-We should be able to run multiple Page Servers that handle sharded data.

pageserver/README.md

@@ -0,0 +1,166 @@
+## Page server architecture
+
+The Page Server has a few different duties:
+
+- Respond to GetPage@LSN requests from the Compute Nodes
+- Receive WAL from WAL safekeeper
+- Replay WAL that's applicable to the chunks that the Page Server maintains
+- Backup to S3
+
+S3 is the main fault-tolerant storage of all data, as there are no Page Server
+replicas. We use a separate fault-tolerant WAL service to reduce latency. It
+keeps track of WAL records which are not syncted to S3 yet.
+
+The Page Server consists of multiple threads that operate on a shared
+repository of page versions:
+
+                                           | WAL
+                                           V
+                                   +--------------+
+                                   |              |
+                                   | WAL receiver |
+                                   |              |
+                                   +--------------+
+                                                                                 +----+
+                  +---------+                              ..........            |    |
+                  |         |                              .        .            |    |
+ GetPage@LSN      |         |                              . backup .  ------->  | S3 |
+------------->    |  Page   |         repository           .        .            |    |
+                  | Service |                              ..........            |    |
+   page           |         |                                                    +----+
+<-------------    |         |
+                  +---------+      +--------------------+
+		                   |   Checkpointing /  |
+				   | Garbage collection |
+                                   +--------------------+
+
+Legend:
+
++--+
+|  |   A thread or multi-threaded service
++--+
+
+....
+.  .   Component at its early development phase.
+....
+
+--->   Data flow
+<---
+
+
+Page Service
+------------
+
+The Page Service listens for GetPage@LSN requests from the Compute Nodes,
+and responds with pages from the repository.
+
+
+WAL Receiver
+------------
+
+The WAL receiver connects to the external WAL safekeeping service (or
+directly to the primary) using PostgreSQL physical streaming
+replication, and continuously receives WAL. It decodes the WAL records,
+and stores them to the repository.
+
+
+Repository
+----------
+
+The repository stores all the page versions, or WAL records needed to
+reconstruct them. Each tenant has a separate Repository, which is
+stored in the .zenith/tenants/<tenantid> directory.
+
+Repository is an abstract trait, defined in `repository.rs`. It is
+implemented by the LayeredRepository object in
+`layered_repository.rs`. There is only that one implementation of the
+Repository trait, but it's still a useful abstraction that keeps the
+interface for the low-level storage functionality clean. The layered
+storage format is described in layered_repository/README.md.
+
+Each repository consists of multiple Timelines. Timeline is a
+workhorse that accepts page changes from the WAL, and serves
+get_page_at_lsn() and get_rel_size() requests. Note: this has nothing
+to do with PostgreSQL WAL timeline. The term "timeline" is mostly
+interchangeable with "branch", there is a one-to-one mapping from
+branch to timeline. A timeline has a unique ID within the tenant,
+represented as 16-byte hex string that never changes, whereas a
+branch is a user-given name for a timeline.
+
+Each repository also has a WAL redo manager associated with it, see
+`walredo.rs`. The WAL redo manager is used to replay PostgreSQL WAL
+records, whenever we need to reconstruct a page version from WAL to
+satisfy a GetPage@LSN request, or to avoid accumulating too much WAL
+for a page. The WAL redo manager uses a Postgres process running in
+special zenith wal-redo mode to do the actual WAL redo, and
+communicates with the process using a pipe.
+
+
+Checkpointing / Garbage Collection
+----------------------------------
+
+Periodically, the checkpointer thread wakes up and performs housekeeping
+duties on the repository. It has two duties:
+
+### Checkpointing
+
+Flush WAL that has accumulated in memory to disk, so that the old WAL
+can be truncated away in the WAL safekeepers. Also, to free up memory
+for receiving new WAL. This process is called "checkpointing". It's
+similar to checkpointing in PostgreSQL or other DBMSs, but in the page
+server, checkpointing happens on a per-segment basis.
+
+### Garbage collection
+
+Remove old on-disk layer files that are no longer needed according to the
+PITR retention policy
+
+
+### Backup service
+
+The backup service, responsible for storing pageserver recovery data externally.
+
+Currently, pageserver stores its files in a filesystem directory it's pointed to.
+That working directory could be rather ephemeral for such cases as "a pageserver pod running in k8s with no persistent volumes attached".
+Therefore, the server interacts with external, more reliable storage to back up and restore its state.
+
+The code for storage support is extensible and can support arbitrary ones as long as they implement a certain Rust trait.
+There are the following implementations present:
+* local filesystem — to use in tests mainly
+* AWS S3           - to use in production
+
+Implementation details are covered in the [backup readme](./src/remote_storage/README.md) and corresponding Rust file docs.
+
+The backup service is disabled by default and can be enabled to interact with a single remote storage.
+
+CLI examples:
+* Local FS: `${PAGESERVER_BIN} --relish-storage-local-path="/some/local/path/"`
+* AWS S3  : `${PAGESERVER_BIN} --relish-storage-s3-bucket="some-sample-bucket" --relish-storage-region="eu-north-1" --relish-storage-access-key="SOMEKEYAAAAASADSAH*#" --relish-storage-secret-access-key="SOMEsEcReTsd292v"`
+
+For Amazon AWS S3, a key id and secret access key could be located in `~/.aws/credentials` if awscli was ever configured to work with the desired bucket, on the AWS Settings page for a certain user. Also note, that the bucket names does not contain any protocols when used on AWS.
+For local S3 installations, refer to the their documentation for name format and credentials.
+
+Similar to other pageserver settings, toml config file can be used to configure either of the storages as backup targets.
+Required sections are:
+
+```toml
+[remote_storage]
+local_path = '/Users/someonetoignore/Downloads/tmp_dir/'
+```
+
+or
+
+```toml
+[remote_storage]
+bucket_name = 'some-sample-bucket'
+bucket_region = 'eu-north-1'
+access_key_id = 'SOMEKEYAAAAASADSAH*#'
+secret_access_key = 'SOMEsEcReTsd292v'
+```
+
+Also, `AWS_SECRET_ACCESS_KEY` and `AWS_ACCESS_KEY_ID` variables can be used to specify the credentials instead of any of the ways above.
+
+TODO: Sharding
+--------------------
+
+We should be able to run multiple Page Servers that handle sharded data.

pageserver/src/basebackup.rs

@@ -10,8 +10,10 @@
 //! This module is responsible for creation of such tarball
 //! from data stored in object storage.
 //!
+use anyhow::Result;
 use bytes::{BufMut, BytesMut};
 use log::*;
+use std::fmt::Write as FmtWrite;
 use std::io;
 use std::io::Write;
 use std::sync::Arc;
@@ -30,29 +32,72 @@ use zenith_utils::lsn::Lsn;
 pub struct Basebackup<'a> {
     ar: Builder<&'a mut dyn Write>,
     timeline: &'a Arc<dyn Timeline>,
-    lsn: Lsn,
+    pub lsn: Lsn,
     prev_record_lsn: Lsn,
 }
 
+// Create basebackup with non-rel data in it. Omit relational data.
+//
+// Currently we use empty lsn in two cases:
+//  * During the basebackup right after timeline creation
+//  * When working without safekeepers. In this situation it is important to match the lsn
+//    we are taking basebackup on with the lsn that is used in pageserver's walreceiver
+//    to start the replication.
 impl<'a> Basebackup<'a> {
     pub fn new(
         write: &'a mut dyn Write,
         timeline: &'a Arc<dyn Timeline>,
-        lsn: Lsn,
-        prev_record_lsn: Lsn,
-    ) -> Basebackup<'a> {
-        Basebackup {
+        req_lsn: Option<Lsn>,
+    ) -> Result<Basebackup<'a>> {
+        // Compute postgres doesn't have any previous WAL files, but the first
+        // record that it's going to write needs to include the LSN of the
+        // previous record (xl_prev). We include prev_record_lsn in the
+        // "zenith.signal" file, so that postgres can read it during startup.
+        //
+        // We don't keep full history of record boundaries in the page server,
+        // however, only the predecessor of the latest record on each
+        // timeline. So we can only provide prev_record_lsn when you take a
+        // base backup at the end of the timeline, i.e. at last_record_lsn.
+        // Even at the end of the timeline, we sometimes don't have a valid
+        // prev_lsn value; that happens if the timeline was just branched from
+        // an old LSN and it doesn't have any WAL of its own yet. We will set
+        // prev_lsn to Lsn(0) if we cannot provide the correct value.
+        let (backup_prev, backup_lsn) = if let Some(req_lsn) = req_lsn {
+            // Backup was requested at a particular LSN. Wait for it to arrive.
+            timeline.wait_lsn(req_lsn)?;
+
+            // If the requested point is the end of the timeline, we can
+            // provide prev_lsn. (get_last_record_rlsn() might return it as
+            // zero, though, if no WAL has been generated on this timeline
+            // yet.)
+            let end_of_timeline = timeline.get_last_record_rlsn();
+            if req_lsn == end_of_timeline.last {
+                (end_of_timeline.prev, req_lsn)
+            } else {
+                (Lsn(0), req_lsn)
+            }
+        } else {
+            // Backup was requested at end of the timeline.
+            let end_of_timeline = timeline.get_last_record_rlsn();
+            (end_of_timeline.prev, end_of_timeline.last)
+        };
+
+        info!(
+            "taking basebackup lsn={}, prev_lsn={}",
+            backup_lsn, backup_prev
+        );
+
+        Ok(Basebackup {
             ar: Builder::new(write),
             timeline,
-            lsn,
-            prev_record_lsn,
-        }
+            lsn: backup_lsn,
+            prev_record_lsn: backup_prev,
+        })
     }
 
     pub fn send_tarball(&mut self) -> anyhow::Result<()> {
         // Create pgdata subdirs structure
         for dir in pg_constants::PGDATA_SUBDIRS.iter() {
-            info!("send subdir {:?}", *dir);
             let header = new_tar_header_dir(*dir)?;
             self.ar.append(&header, &mut io::empty())?;
         }
@@ -61,10 +106,10 @@ impl<'a> Basebackup<'a> {
         for filepath in pg_constants::PGDATA_SPECIAL_FILES.iter() {
             if *filepath == "pg_hba.conf" {
                 let data = pg_constants::PG_HBA.as_bytes();
-                let header = new_tar_header(&filepath, data.len() as u64)?;
-                self.ar.append(&header, &data[..])?;
+                let header = new_tar_header(filepath, data.len() as u64)?;
+                self.ar.append(&header, data)?;
             } else {
-                let header = new_tar_header(&filepath, 0)?;
+                let header = new_tar_header(filepath, 0)?;
                 self.ar.append(&header, &mut io::empty())?;
             }
         }
@@ -114,11 +159,9 @@ impl<'a> Basebackup<'a> {
         let mut slru_buf: Vec<u8> =
             Vec::with_capacity(nblocks as usize * pg_constants::BLCKSZ as usize);
         for blknum in 0..nblocks {
-            let img = self.timeline.get_page_at_lsn_nowait(
-                RelishTag::Slru { slru, segno },
-                blknum,
-                self.lsn,
-            )?;
+            let img =
+                self.timeline
+                    .get_page_at_lsn(RelishTag::Slru { slru, segno }, blknum, self.lsn)?;
             assert!(img.len() == pg_constants::BLCKSZ as usize);
 
             slru_buf.extend_from_slice(&img);
@@ -137,20 +180,18 @@ impl<'a> Basebackup<'a> {
     // Along with them also send PG_VERSION for each database.
     //
     fn add_relmap_file(&mut self, spcnode: u32, dbnode: u32) -> anyhow::Result<()> {
-        let img = self.timeline.get_page_at_lsn_nowait(
+        let img = self.timeline.get_page_at_lsn(
             RelishTag::FileNodeMap { spcnode, dbnode },
             0,
             self.lsn,
         )?;
         let path = if spcnode == pg_constants::GLOBALTABLESPACE_OID {
-            let dst_path = "PG_VERSION";
             let version_bytes = pg_constants::PG_MAJORVERSION.as_bytes();
-            let header = new_tar_header(&dst_path, version_bytes.len() as u64)?;
-            self.ar.append(&header, &version_bytes[..])?;
+            let header = new_tar_header("PG_VERSION", version_bytes.len() as u64)?;
+            self.ar.append(&header, version_bytes)?;
 
-            let dst_path = format!("global/PG_VERSION");
-            let header = new_tar_header(&dst_path, version_bytes.len() as u64)?;
-            self.ar.append(&header, &version_bytes[..])?;
+            let header = new_tar_header("global/PG_VERSION", version_bytes.len() as u64)?;
+            self.ar.append(&header, version_bytes)?;
 
             String::from("global/pg_filenode.map") // filenode map for global tablespace
         } else {
@@ -165,7 +206,7 @@ impl<'a> Basebackup<'a> {
             let dst_path = format!("base/{}/PG_VERSION", dbnode);
             let version_bytes = pg_constants::PG_MAJORVERSION.as_bytes();
             let header = new_tar_header(&dst_path, version_bytes.len() as u64)?;
-            self.ar.append(&header, &version_bytes[..])?;
+            self.ar.append(&header, version_bytes)?;
 
             format!("base/{}/pg_filenode.map", dbnode)
         };
@@ -179,18 +220,18 @@ impl<'a> Basebackup<'a> {
     // Extract twophase state files
     //
     fn add_twophase_file(&mut self, xid: TransactionId) -> anyhow::Result<()> {
-        if let Ok(img) =
-            self.timeline
-                .get_page_at_lsn_nowait(RelishTag::TwoPhase { xid }, 0, self.lsn)
-        {
-            let mut buf = BytesMut::new();
-            buf.extend_from_slice(&img[..]);
-            let crc = crc32c::crc32c(&img[..]);
-            buf.put_u32_le(crc);
-            let path = format!("pg_twophase/{:>08X}", xid);
-            let header = new_tar_header(&path, buf.len() as u64)?;
-            self.ar.append(&header, &buf[..])?;
-        }
+        let img = self
+            .timeline
+            .get_page_at_lsn(RelishTag::TwoPhase { xid }, 0, self.lsn)?;
+
+        let mut buf = BytesMut::new();
+        buf.extend_from_slice(&img[..]);
+        let crc = crc32c::crc32c(&img[..]);
+        buf.put_u32_le(crc);
+        let path = format!("pg_twophase/{:>08X}", xid);
+        let header = new_tar_header(&path, buf.len() as u64)?;
+        self.ar.append(&header, &buf[..])?;
+
         Ok(())
     }
 
@@ -199,23 +240,17 @@ impl<'a> Basebackup<'a> {
     // Also send zenith.signal file with extra bootstrap data.
     //
     fn add_pgcontrol_file(&mut self) -> anyhow::Result<()> {
-        let checkpoint_bytes =
-            self.timeline
-                .get_page_at_lsn_nowait(RelishTag::Checkpoint, 0, self.lsn)?;
+        let checkpoint_bytes = self
+            .timeline
+            .get_page_at_lsn(RelishTag::Checkpoint, 0, self.lsn)?;
         let pg_control_bytes =
             self.timeline
-                .get_page_at_lsn_nowait(RelishTag::ControlFile, 0, self.lsn)?;
+                .get_page_at_lsn(RelishTag::ControlFile, 0, self.lsn)?;
         let mut pg_control = ControlFileData::decode(&pg_control_bytes)?;
         let mut checkpoint = CheckPoint::decode(&checkpoint_bytes)?;
 
-        // Generate new pg_control and WAL needed for bootstrap
-        let checkpoint_segno = self.lsn.segment_number(pg_constants::WAL_SEGMENT_SIZE);
-        let checkpoint_lsn = XLogSegNoOffsetToRecPtr(
-            checkpoint_segno,
-            XLOG_SIZE_OF_XLOG_LONG_PHD as u32,
-            pg_constants::WAL_SEGMENT_SIZE,
-        );
-        checkpoint.redo = self.lsn.0 + self.lsn.calc_padding(8u32);
+        // Generate new pg_control needed for bootstrap
+        checkpoint.redo = normalize_lsn(self.lsn, pg_constants::WAL_SEGMENT_SIZE).0;
 
         //reset some fields we don't want to preserve
         //TODO Check this.
@@ -223,14 +258,24 @@ impl<'a> Basebackup<'a> {
         checkpoint.oldestActiveXid = 0;
 
         //save new values in pg_control
-        pg_control.checkPoint = checkpoint_lsn;
+        pg_control.checkPoint = 0;
         pg_control.checkPointCopy = checkpoint;
         pg_control.state = pg_constants::DB_SHUTDOWNED;
 
         // add zenith.signal file
+        let mut zenith_signal = String::new();
+        if self.prev_record_lsn == Lsn(0) {
+            if self.lsn == self.timeline.get_ancestor_lsn() {
+                write!(zenith_signal, "PREV LSN: none")?;
+            } else {
+                write!(zenith_signal, "PREV LSN: invalid")?;
+            }
+        } else {
+            write!(zenith_signal, "PREV LSN: {}", self.prev_record_lsn)?;
+        }
         self.ar.append(
-            &new_tar_header("zenith.signal", 8)?,
-            &self.prev_record_lsn.0.to_le_bytes()[..],
+            &new_tar_header("zenith.signal", zenith_signal.len() as u64)?,
+            zenith_signal.as_bytes(),
         )?;
 
         //send pg_control
@@ -239,14 +284,15 @@ impl<'a> Basebackup<'a> {
         self.ar.append(&header, &pg_control_bytes[..])?;
 
         //send wal segment
+        let segno = self.lsn.segment_number(pg_constants::WAL_SEGMENT_SIZE);
         let wal_file_name = XLogFileName(
             1, // FIXME: always use Postgres timeline 1
-            checkpoint_segno,
+            segno,
             pg_constants::WAL_SEGMENT_SIZE,
         );
         let wal_file_path = format!("pg_wal/{}", wal_file_name);
         let header = new_tar_header(&wal_file_path, pg_constants::WAL_SEGMENT_SIZE as u64)?;
-        let wal_seg = generate_wal_segment(&pg_control);
+        let wal_seg = generate_wal_segment(segno, pg_control.system_identifier);
         assert!(wal_seg.len() == pg_constants::WAL_SEGMENT_SIZE);
         self.ar.append(&header, &wal_seg[..])?;
         Ok(())

pageserver/src/bin/dump_layerfile.rs

@@ -0,0 +1,27 @@
+//! Main entry point for the dump_layerfile executable
+//!
+//! A handy tool for debugging, that's all.
+use anyhow::Result;
+use clap::{App, Arg};
+use pageserver::layered_repository::dump_layerfile_from_path;
+use std::path::PathBuf;
+use zenith_utils::GIT_VERSION;
+
+fn main() -> Result<()> {
+    let arg_matches = App::new("Zenith dump_layerfile utility")
+        .about("Dump contents of one layer file, for debugging")
+        .version(GIT_VERSION)
+        .arg(
+            Arg::with_name("path")
+                .help("Path to file to dump")
+                .required(true)
+                .index(1),
+        )
+        .get_matches();
+
+    let path = PathBuf::from(arg_matches.value_of("path").unwrap());
+
+    dump_layerfile_from_path(&path)?;
+
+    Ok(())
+}

pageserver/src/bin/pageserver.rs

@@ -2,46 +2,78 @@
 // Main entry point for the Page Server executable
 //
 
-use log::*;
 use serde::{Deserialize, Serialize};
 use std::{
     env,
-    net::TcpListener,
     path::{Path, PathBuf},
-    process::exit,
     str::FromStr,
-    sync::Arc,
     thread,
-    time::Duration,
 };
-use zenith_utils::{auth::JwtAuth, postgres_backend::AuthType};
+use tracing::*;
+use zenith_utils::{auth::JwtAuth, logging, postgres_backend::AuthType, tcp_listener, GIT_VERSION};
+
+use anyhow::{bail, ensure, Context, Result};
+use signal_hook::consts::signal::*;
+use signal_hook::consts::TERM_SIGNALS;
+use signal_hook::flag;
+use signal_hook::iterator::exfiltrator::WithOrigin;
+use signal_hook::iterator::SignalsInfo;
+use std::process::exit;
+use std::sync::atomic::AtomicBool;
+use std::sync::Arc;
 
-use anyhow::{ensure, Result};
 use clap::{App, Arg, ArgMatches};
 use daemonize::Daemonize;
 
-use pageserver::{branches, logger, page_cache, page_service, PageServerConf, RepositoryFormat};
-use zenith_utils::http_endpoint;
+use pageserver::{
+    branches, defaults::*, http, page_service, remote_storage, tenant_mgr, PageServerConf,
+    RemoteStorageConfig, RemoteStorageKind, S3Config, LOG_FILE_NAME,
+};
+use zenith_utils::http::endpoint;
+use zenith_utils::postgres_backend;
 
-const DEFAULT_LISTEN_ADDR: &str = "127.0.0.1:64000";
-const DEFAULT_HTTP_ENDPOINT_ADDR: &str = "127.0.0.1:9898";
-
-const DEFAULT_GC_HORIZON: u64 = 64 * 1024 * 1024;
-const DEFAULT_GC_PERIOD: Duration = Duration::from_secs(10);
-
-const DEFAULT_SUPERUSER: &str = "zenith_admin";
+use const_format::formatcp;
 
 /// String arguments that can be declared via CLI or config file
-#[derive(Serialize, Deserialize)]
+#[derive(Serialize, Deserialize, PartialEq, Eq, Clone)]
 struct CfgFileParams {
-    listen_addr: Option<String>,
-    http_endpoint_addr: Option<String>,
+    listen_pg_addr: Option<String>,
+    listen_http_addr: Option<String>,
+    checkpoint_distance: Option<String>,
+    checkpoint_period: Option<String>,
     gc_horizon: Option<String>,
     gc_period: Option<String>,
+    open_mem_limit: Option<String>,
     pg_distrib_dir: Option<String>,
     auth_validation_public_key_path: Option<String>,
     auth_type: Option<String>,
-    repository_format: Option<String>,
+    remote_storage_max_concurrent_sync: Option<String>,
+    /////////////////////////////////
+    //// Don't put `Option<String>` and other "simple" values below.
+    ////
+    /// `Option<RemoteStorage>` is a <a href='https://toml.io/en/v1.0.0#table'>table</a> in TOML.
+    /// Values in TOML cannot be defined after tables (other tables can),
+    /// and [`toml`] crate serializes all fields in the order of their appearance.
+    ////////////////////////////////
+    remote_storage: Option<RemoteStorage>,
+}
+
+#[derive(Serialize, Deserialize, PartialEq, Eq, Clone)]
+// Without this attribute, enums with values won't be serialized by the `toml` library (but can be deserialized nonetheless!).
+// See https://github.com/alexcrichton/toml-rs/blob/6c162e6562c3e432bf04c82a3d1d789d80761a86/examples/enum_external.rs for the examples
+#[serde(untagged)]
+enum RemoteStorage {
+    Local {
+        local_path: String,
+    },
+    AwsS3 {
+        bucket_name: String,
+        bucket_region: String,
+        #[serde(skip_serializing)]
+        access_key_id: Option<String>,
+        #[serde(skip_serializing)]
+        secret_access_key: Option<String>,
+    },
 }
 
 impl CfgFileParams {
@@ -51,15 +83,34 @@ impl CfgFileParams {
             arg_matches.value_of(arg_name).map(str::to_owned)
         };
 
+        let remote_storage = if let Some(local_path) = get_arg("relish-storage-local-path") {
+            Some(RemoteStorage::Local { local_path })
+        } else if let Some((bucket_name, bucket_region)) =
+            get_arg("relish-storage-s3-bucket").zip(get_arg("relish-storage-region"))
+        {
+            Some(RemoteStorage::AwsS3 {
+                bucket_name,
+                bucket_region,
+                access_key_id: get_arg("relish-storage-access-key"),
+                secret_access_key: get_arg("relish-storage-secret-access-key"),
+            })
+        } else {
+            None
+        };
+
         Self {
-            listen_addr: get_arg("listen"),
-            http_endpoint_addr: get_arg("http_endpoint"),
+            listen_pg_addr: get_arg("listen-pg"),
+            listen_http_addr: get_arg("listen-http"),
+            checkpoint_distance: get_arg("checkpoint_distance"),
+            checkpoint_period: get_arg("checkpoint_period"),
             gc_horizon: get_arg("gc_horizon"),
             gc_period: get_arg("gc_period"),
+            open_mem_limit: get_arg("open_mem_limit"),
             pg_distrib_dir: get_arg("postgres-distrib"),
             auth_validation_public_key_path: get_arg("auth-validation-public-key-path"),
             auth_type: get_arg("auth-type"),
-            repository_format: get_arg("repository-format"),
+            remote_storage,
+            remote_storage_max_concurrent_sync: get_arg("relish-storage-max-concurrent-sync"),
         }
     }
 
@@ -67,16 +118,22 @@ impl CfgFileParams {
     fn or(self, other: CfgFileParams) -> Self {
         // TODO cleaner way to do this
         Self {
-            listen_addr: self.listen_addr.or(other.listen_addr),
-            http_endpoint_addr: self.http_endpoint_addr.or(other.http_endpoint_addr),
+            listen_pg_addr: self.listen_pg_addr.or(other.listen_pg_addr),
+            listen_http_addr: self.listen_http_addr.or(other.listen_http_addr),
+            checkpoint_distance: self.checkpoint_distance.or(other.checkpoint_distance),
+            checkpoint_period: self.checkpoint_period.or(other.checkpoint_period),
             gc_horizon: self.gc_horizon.or(other.gc_horizon),
             gc_period: self.gc_period.or(other.gc_period),
+            open_mem_limit: self.open_mem_limit.or(other.open_mem_limit),
             pg_distrib_dir: self.pg_distrib_dir.or(other.pg_distrib_dir),
             auth_validation_public_key_path: self
                 .auth_validation_public_key_path
                 .or(other.auth_validation_public_key_path),
             auth_type: self.auth_type.or(other.auth_type),
-            repository_format: self.repository_format.or(other.repository_format),
+            remote_storage: self.remote_storage.or(other.remote_storage),
+            remote_storage_max_concurrent_sync: self
+                .remote_storage_max_concurrent_sync
+                .or(other.remote_storage_max_concurrent_sync),
         }
     }
 
@@ -84,14 +141,23 @@ impl CfgFileParams {
     fn try_into_config(&self) -> Result<PageServerConf> {
         let workdir = PathBuf::from(".");
 
-        let listen_addr = match self.listen_addr.as_ref() {
+        let listen_pg_addr = match self.listen_pg_addr.as_ref() {
             Some(addr) => addr.clone(),
-            None => DEFAULT_LISTEN_ADDR.to_owned(),
+            None => DEFAULT_PG_LISTEN_ADDR.to_owned(),
         };
 
-        let http_endpoint_addr = match self.http_endpoint_addr.as_ref() {
+        let listen_http_addr = match self.listen_http_addr.as_ref() {
             Some(addr) => addr.clone(),
-            None => DEFAULT_HTTP_ENDPOINT_ADDR.to_owned(),
+            None => DEFAULT_HTTP_LISTEN_ADDR.to_owned(),
+        };
+
+        let checkpoint_distance: u64 = match self.checkpoint_distance.as_ref() {
+            Some(checkpoint_distance_str) => checkpoint_distance_str.parse()?,
+            None => DEFAULT_CHECKPOINT_DISTANCE,
+        };
+        let checkpoint_period = match self.checkpoint_period.as_ref() {
+            Some(checkpoint_period_str) => humantime::parse_duration(checkpoint_period_str)?,
+            None => DEFAULT_CHECKPOINT_PERIOD,
         };
 
         let gc_horizon: u64 = match self.gc_horizon.as_ref() {
@@ -103,6 +169,11 @@ impl CfgFileParams {
             None => DEFAULT_GC_PERIOD,
         };
 
+        let open_mem_limit: usize = match self.open_mem_limit.as_ref() {
+            Some(open_mem_limit_str) => open_mem_limit_str.parse()?,
+            None => DEFAULT_OPEN_MEM_LIMIT,
+        };
+
         let pg_distrib_dir = match self.pg_distrib_dir.as_ref() {
             Some(pg_distrib_dir_str) => PathBuf::from(pg_distrib_dir_str),
             None => env::current_dir()?.join("tmp_install"),
@@ -117,11 +188,11 @@ impl CfgFileParams {
             .auth_type
             .as_ref()
             .map_or(Ok(AuthType::Trust), |auth_type| {
-                AuthType::from_str(&auth_type)
+                AuthType::from_str(auth_type)
             })?;
 
         if !pg_distrib_dir.join("bin/postgres").exists() {
-            anyhow::bail!("Can't find postgres binary at {:?}", pg_distrib_dir);
+            bail!("Can't find postgres binary at {:?}", pg_distrib_dir);
         }
 
         if auth_type == AuthType::ZenithJWT {
@@ -136,23 +207,43 @@ impl CfgFileParams {
             );
         }
 
-        let repository_format = match self.repository_format.as_ref() {
-            Some(repo_format_str) if repo_format_str == "rocksdb" => RepositoryFormat::RocksDb,
-            Some(repo_format_str) if repo_format_str == "layered" => RepositoryFormat::Layered,
-            Some(repo_format_str) => anyhow::bail!(
-                "invalid --repository-format '{}', must be 'rocksdb' or 'layered'",
-                repo_format_str
-            ),
-            None => RepositoryFormat::Layered, // default
+        let max_concurrent_sync = match self.remote_storage_max_concurrent_sync.as_deref() {
+            Some(number_str) => number_str.parse()?,
+            None => DEFAULT_REMOTE_STORAGE_MAX_CONCURRENT_SYNC_LIMITS,
         };
+        let remote_storage_config = self.remote_storage.as_ref().map(|storage_params| {
+            let storage = match storage_params.clone() {
+                RemoteStorage::Local { local_path } => {
+                    RemoteStorageKind::LocalFs(PathBuf::from(local_path))
+                }
+                RemoteStorage::AwsS3 {
+                    bucket_name,
+                    bucket_region,
+                    access_key_id,
+                    secret_access_key,
+                } => RemoteStorageKind::AwsS3(S3Config {
+                    bucket_name,
+                    bucket_region,
+                    access_key_id,
+                    secret_access_key,
+                }),
+            };
+            RemoteStorageConfig {
+                max_concurrent_sync,
+                storage,
+            }
+        });
 
         Ok(PageServerConf {
             daemonize: false,
 
-            listen_addr,
-            http_endpoint_addr,
+            listen_pg_addr,
+            listen_http_addr,
+            checkpoint_distance,
+            checkpoint_period,
             gc_horizon,
             gc_period,
+            open_mem_limit,
 
             superuser: String::from(DEFAULT_SUPERUSER),
 
@@ -162,21 +253,30 @@ impl CfgFileParams {
 
             auth_validation_public_key_path,
             auth_type,
-
-            repository_format,
+            remote_storage_config,
         })
     }
 }
 
 fn main() -> Result<()> {
+    zenith_metrics::set_common_metrics_prefix("pageserver");
     let arg_matches = App::new("Zenith page server")
         .about("Materializes WAL stream to pages and serves them to the postgres")
+        .version(GIT_VERSION)
         .arg(
-            Arg::with_name("listen")
+            Arg::with_name("listen-pg")
                 .short("l")
-                .long("listen")
+                .long("listen-pg")
+                .alias("listen") // keep some compatibility
                 .takes_value(true)
-                .help("listen for incoming page requests on ip:port (default: 127.0.0.1:5430)"),
+                .help(formatcp!("listen for incoming page requests on ip:port (default: {DEFAULT_PG_LISTEN_ADDR})")),
+        )
+        .arg(
+            Arg::with_name("listen-http")
+                .long("listen-http")
+                .alias("http_endpoint") // keep some compatibility
+                .takes_value(true)
+                .help(formatcp!("http endpoint address for metrics and management API calls on ip:port (default: {DEFAULT_HTTP_LISTEN_ADDR})")),
         )
         .arg(
             Arg::with_name("daemonize")
@@ -191,6 +291,18 @@ fn main() -> Result<()> {
                 .takes_value(false)
                 .help("Initialize pageserver repo"),
         )
+        .arg(
+            Arg::with_name("checkpoint_distance")
+                .long("checkpoint_distance")
+                .takes_value(true)
+                .help("Distance from current LSN to perform checkpoint of in-memory layers"),
+        )
+        .arg(
+            Arg::with_name("checkpoint_period")
+                .long("checkpoint_period")
+                .takes_value(true)
+                .help("Interval between checkpoint iterations"),
+        )
         .arg(
             Arg::with_name("gc_horizon")
                 .long("gc_horizon")
@@ -203,6 +315,12 @@ fn main() -> Result<()> {
                 .takes_value(true)
                 .help("Interval between garbage collector iterations"),
         )
+        .arg(
+            Arg::with_name("open_mem_limit")
+                .long("open_mem_limit")
+                .takes_value(true)
+                .help("Amount of memory reserved for buffering incoming WAL"),
+        )
         .arg(
             Arg::with_name("workdir")
                 .short("D")
@@ -236,15 +354,55 @@ fn main() -> Result<()> {
                 .help("Authentication scheme type. One of: Trust, MD5, ZenithJWT"),
         )
         .arg(
-            Arg::with_name("repository-format")
-                .long("repository-format")
+            Arg::with_name("relish-storage-local-path")
+                .long("relish-storage-local-path")
                 .takes_value(true)
-                .help("Which repository implementation to use, 'rocksdb' or 'layered'"),
+                .help("Path to the local directory, to be used as an external relish storage")
+                .conflicts_with_all(&[
+                    "relish-storage-s3-bucket",
+                    "relish-storage-region",
+                    "relish-storage-access-key",
+                    "relish-storage-secret-access-key",
+                ]),
+        )
+        .arg(
+            Arg::with_name("relish-storage-s3-bucket")
+                .long("relish-storage-s3-bucket")
+                .takes_value(true)
+                .help("Name of the AWS S3 bucket to use an external relish storage")
+                .requires("relish-storage-region"),
+        )
+        .arg(
+            Arg::with_name("relish-storage-region")
+                .long("relish-storage-region")
+                .takes_value(true)
+                .help("Region of the AWS S3 bucket"),
+        )
+        .arg(
+            Arg::with_name("relish-storage-access-key")
+                .long("relish-storage-access-key")
+                .takes_value(true)
+                .help("Credentials to access the AWS S3 bucket"),
+        )
+        .arg(
+            Arg::with_name("relish-storage-secret-access-key")
+                .long("relish-storage-secret-access-key")
+                .takes_value(true)
+                .help("Credentials to access the AWS S3 bucket"),
+        )
+        .arg(
+            Arg::with_name("relish-storage-max-concurrent-sync")
+                .long("relish-storage-max-concurrent-sync")
+                .takes_value(true)
+                .help("Maximum allowed concurrent synchronisations with storage"),
         )
         .get_matches();
 
     let workdir = Path::new(arg_matches.value_of("workdir").unwrap_or(".zenith"));
-    let cfg_file_path = workdir.canonicalize()?.join("pageserver.toml");
+    let cfg_file_path = workdir
+        .canonicalize()
+        .with_context(|| format!("Error opening workdir '{}'", workdir.display()))?
+        .join("pageserver.toml");
 
     let args_params = CfgFileParams::from_args(&arg_matches);
 
@@ -256,22 +414,37 @@ fn main() -> Result<()> {
         args_params
     } else {
         // Supplement the CLI arguments with the config file
-        let cfg_file_contents = std::fs::read_to_string(&cfg_file_path)?;
-        let file_params: CfgFileParams = toml::from_str(&cfg_file_contents)?;
+        let cfg_file_contents = std::fs::read_to_string(&cfg_file_path)
+            .with_context(|| format!("No pageserver config at '{}'", cfg_file_path.display()))?;
+        let file_params: CfgFileParams = toml::from_str(&cfg_file_contents).with_context(|| {
+            format!(
+                "Failed to read '{}' as pageserver config",
+                cfg_file_path.display()
+            )
+        })?;
         args_params.or(file_params)
     };
 
     // Set CWD to workdir for non-daemon modes
-    env::set_current_dir(&workdir)?;
+    env::set_current_dir(&workdir).with_context(|| {
+        format!(
+            "Failed to set application's current dir to '{}'",
+            workdir.display()
+        )
+    })?;
 
     // Ensure the config is valid, even if just init-ing
-    let mut conf = params.try_into_config()?;
+    let mut conf = params.try_into_config().with_context(|| {
+        format!(
+            "Pageserver config at '{}' is not valid",
+            cfg_file_path.display()
+        )
+    })?;
 
     conf.daemonize = arg_matches.is_present("daemonize");
 
     if init && conf.daemonize {
-        eprintln!("--daemonize cannot be used with --init");
-        exit(1);
+        bail!("--daemonize cannot be used with --init")
     }
 
     // The configuration is all set up now. Turn it into a 'static
@@ -281,32 +454,59 @@ fn main() -> Result<()> {
 
     // Create repo and exit if init was requested
     if init {
-        branches::init_pageserver(conf, create_tenant)?;
+        branches::init_pageserver(conf, create_tenant).context("Failed to init pageserver")?;
         // write the config file
-        let cfg_file_contents = toml::to_string_pretty(&params)?;
+        let cfg_file_contents = toml::to_string_pretty(&params)
+            .context("Failed to create pageserver config contents for initialisation")?;
         // TODO support enable-auth flag
-        std::fs::write(&cfg_file_path, cfg_file_contents)?;
-
-        return Ok(());
+        std::fs::write(&cfg_file_path, cfg_file_contents).with_context(|| {
+            format!(
+                "Failed to initialize pageserver config at '{}'",
+                cfg_file_path.display()
+            )
+        })?;
+        Ok(())
+    } else {
+        start_pageserver(conf).context("Failed to start pageserver")
     }
-
-    start_pageserver(conf)
 }
 
 fn start_pageserver(conf: &'static PageServerConf) -> Result<()> {
     // Initialize logger
-    let (_scope_guard, log_file) = logger::init_logging(&conf, "pageserver.log")?;
-    let _log_guard = slog_stdlog::init()?;
+    let log_file = logging::init(LOG_FILE_NAME, conf.daemonize)?;
 
-    // Note: this `info!(...)` macro comes from `log` crate
-    info!("standard logging redirected to slog");
+    info!("version: {}", GIT_VERSION);
+
+    let term_now = Arc::new(AtomicBool::new(false));
+    for sig in TERM_SIGNALS {
+        // When terminated by a second term signal, exit with exit code 1.
+        // This will do nothing the first time (because term_now is false).
+        flag::register_conditional_shutdown(*sig, 1, Arc::clone(&term_now))?;
+        // But this will "arm" the above for the second time, by setting it to true.
+        // The order of registering these is important, if you put this one first, it will
+        // first arm and then terminate ‒ all in the first round.
+        flag::register(*sig, Arc::clone(&term_now))?;
+    }
 
     // TODO: Check that it looks like a valid repository before going further
 
+    // bind sockets before daemonizing so we report errors early and do not return until we are listening
+    info!(
+        "Starting pageserver http handler on {}",
+        conf.listen_http_addr
+    );
+    let http_listener = tcp_listener::bind(conf.listen_http_addr.clone())?;
+
+    info!(
+        "Starting pageserver pg protocol handler on {}",
+        conf.listen_pg_addr
+    );
+    let pageserver_listener = tcp_listener::bind(conf.listen_pg_addr.clone())?;
+
     if conf.daemonize {
         info!("daemonizing...");
 
-        // There should'n be any logging to stdin/stdout. Redirect it to the main log so
+        // There shouldn't be any logging to stdin/stdout. Redirect it to the main log so
         // that we will see any accidental manual fprintf's or backtraces.
         let stdout = log_file.try_clone().unwrap();
         let stderr = log_file;
@@ -319,33 +519,43 @@ fn start_pageserver(conf: &'static PageServerConf) -> Result<()> {
 
         match daemonize.start() {
             Ok(_) => info!("Success, daemonized"),
-            Err(e) => error!("Error, {}", e),
+            Err(err) => error!(%err, "could not daemonize"),
         }
     }
 
-    // Spawn a new thread for the http endpoint
-    thread::Builder::new()
-        .name("Metrics thread".into())
-        .spawn(move || http_endpoint::thread_main(conf.http_endpoint_addr.clone()))?;
+    // keep join handles for spawned threads
+    // don't spawn threads before daemonizing
+    let mut join_handles = Vec::new();
 
-    // Check that we can bind to address before starting threads to simplify shutdown
-    // sequence if port is occupied.
-    info!("Starting pageserver on {}", conf.listen_addr);
-    let pageserver_listener = TcpListener::bind(conf.listen_addr.clone())?;
-
-    // Initialize page cache, this will spawn walredo_thread
-    page_cache::init(conf);
+    if let Some(handle) = remote_storage::run_storage_sync_thread(conf)? {
+        join_handles.push(handle);
+    }
+    // Initialize tenant manager.
+    tenant_mgr::init(conf);
 
     // initialize authentication for incoming connections
     let auth = match &conf.auth_type {
-        AuthType::Trust | AuthType::MD5 => Arc::new(None),
+        AuthType::Trust | AuthType::MD5 => None,
         AuthType::ZenithJWT => {
             // unwrap is ok because check is performed when creating config, so path is set and file exists
             let key_path = conf.auth_validation_public_key_path.as_ref().unwrap();
-            Arc::new(Some(JwtAuth::from_key_path(key_path)?))
+            Some(JwtAuth::from_key_path(key_path)?.into())
         }
     };
     info!("Using auth: {:#?}", conf.auth_type);
+
+    // Spawn a new thread for the http endpoint
+    // bind before launching separate thread so the error reported before startup exits
+    let cloned = auth.clone();
+    let http_endpoint_thread = thread::Builder::new()
+        .name("http_endpoint_thread".into())
+        .spawn(move || {
+            let router = http::make_router(conf, cloned);
+            endpoint::serve_thread_main(router, http_listener)
+        })?;
+
+    join_handles.push(http_endpoint_thread);
+
     // Spawn a thread to listen for connections. It will spawn further threads
     // for each connection.
     let page_service_thread = thread::Builder::new()
@@ -354,9 +564,177 @@ fn start_pageserver(conf: &'static PageServerConf) -> Result<()> {
             page_service::thread_main(conf, auth, pageserver_listener, conf.auth_type)
         })?;
 
-    page_service_thread
-        .join()
-        .expect("Page service thread has panicked")?;
+    for info in SignalsInfo::<WithOrigin>::new(TERM_SIGNALS)?.into_iter() {
+        match info.signal {
+            SIGQUIT => {
+                info!("Got SIGQUIT. Terminate pageserver in immediate shutdown mode");
+                exit(111);
+            }
+            SIGINT | SIGTERM => {
+                info!("Got SIGINT/SIGTERM. Terminate gracefully in fast shutdown mode");
+                // Terminate postgres backends
+                postgres_backend::set_pgbackend_shutdown_requested();
+                // Stop all tenants and flush their data
+                tenant_mgr::shutdown_all_tenants()?;
+                // Wait for pageservice thread to complete the job
+                page_service_thread
+                    .join()
+                    .expect("thread panicked")
+                    .expect("thread exited with an error");
+
+                // Shut down http router
+                endpoint::shutdown();
+
+                // Wait for all threads
+                for handle in join_handles.into_iter() {
+                    handle
+                        .join()
+                        .expect("thread panicked")
+                        .expect("thread exited with an error");
+                }
+                info!("Pageserver shut down successfully completed");
+                exit(0);
+            }
+            unknown_signal => {
+                debug!("Unknown signal {}", unknown_signal);
+            }
+        }
+    }
 
     Ok(())
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn page_server_conf_toml_serde() {
+        let params = CfgFileParams {
+            listen_pg_addr: Some("listen_pg_addr_VALUE".to_string()),
+            listen_http_addr: Some("listen_http_addr_VALUE".to_string()),
+            checkpoint_distance: Some("checkpoint_distance_VALUE".to_string()),
+            checkpoint_period: Some("checkpoint_period_VALUE".to_string()),
+            gc_horizon: Some("gc_horizon_VALUE".to_string()),
+            gc_period: Some("gc_period_VALUE".to_string()),
+            open_mem_limit: Some("open_mem_limit_VALUE".to_string()),
+            pg_distrib_dir: Some("pg_distrib_dir_VALUE".to_string()),
+            auth_validation_public_key_path: Some(
+                "auth_validation_public_key_path_VALUE".to_string(),
+            ),
+            auth_type: Some("auth_type_VALUE".to_string()),
+            remote_storage: Some(RemoteStorage::Local {
+                local_path: "remote_storage_local_VALUE".to_string(),
+            }),
+            remote_storage_max_concurrent_sync: Some(
+                "remote_storage_max_concurrent_sync_VALUE".to_string(),
+            ),
+        };
+
+        let toml_string = toml::to_string(&params).expect("Failed to serialize correct config");
+        let toml_pretty_string =
+            toml::to_string_pretty(&params).expect("Failed to serialize correct config");
+        assert_eq!(
+            r#"listen_pg_addr = 'listen_pg_addr_VALUE'
+listen_http_addr = 'listen_http_addr_VALUE'
+checkpoint_distance = 'checkpoint_distance_VALUE'
+checkpoint_period = 'checkpoint_period_VALUE'
+gc_horizon = 'gc_horizon_VALUE'
+gc_period = 'gc_period_VALUE'
+open_mem_limit = 'open_mem_limit_VALUE'
+pg_distrib_dir = 'pg_distrib_dir_VALUE'
+auth_validation_public_key_path = 'auth_validation_public_key_path_VALUE'
+auth_type = 'auth_type_VALUE'
+remote_storage_max_concurrent_sync = 'remote_storage_max_concurrent_sync_VALUE'
+
+[remote_storage]
+local_path = 'remote_storage_local_VALUE'
+"#,
+            toml_pretty_string
+        );
+
+        let params_from_serialized: CfgFileParams = toml::from_str(&toml_string)
+            .expect("Failed to deserialize the serialization result of the config");
+        let params_from_serialized_pretty: CfgFileParams = toml::from_str(&toml_pretty_string)
+            .expect("Failed to deserialize the prettified serialization result of the config");
+        assert!(
+            params_from_serialized == params,
+            "Expected the same config in the end of config -> serialize -> deserialize chain"
+        );
+        assert!(
+            params_from_serialized_pretty == params,
+            "Expected the same config in the end of config -> serialize pretty -> deserialize chain"
+        );
+    }
+
+    #[test]
+    fn credentials_omitted_during_serialization() {
+        let params = CfgFileParams {
+            listen_pg_addr: Some("listen_pg_addr_VALUE".to_string()),
+            listen_http_addr: Some("listen_http_addr_VALUE".to_string()),
+            checkpoint_distance: Some("checkpoint_distance_VALUE".to_string()),
+            checkpoint_period: Some("checkpoint_period_VALUE".to_string()),
+            gc_horizon: Some("gc_horizon_VALUE".to_string()),
+            gc_period: Some("gc_period_VALUE".to_string()),
+            open_mem_limit: Some("open_mem_limit_VALUE".to_string()),
+            pg_distrib_dir: Some("pg_distrib_dir_VALUE".to_string()),
+            auth_validation_public_key_path: Some(
+                "auth_validation_public_key_path_VALUE".to_string(),
+            ),
+            auth_type: Some("auth_type_VALUE".to_string()),
+            remote_storage: Some(RemoteStorage::AwsS3 {
+                bucket_name: "bucket_name_VALUE".to_string(),
+                bucket_region: "bucket_region_VALUE".to_string(),
+                access_key_id: Some("access_key_id_VALUE".to_string()),
+                secret_access_key: Some("secret_access_key_VALUE".to_string()),
+            }),
+            remote_storage_max_concurrent_sync: Some(
+                "remote_storage_max_concurrent_sync_VALUE".to_string(),
+            ),
+        };
+
+        let toml_string = toml::to_string(&params).expect("Failed to serialize correct config");
+        let toml_pretty_string =
+            toml::to_string_pretty(&params).expect("Failed to serialize correct config");
+        assert_eq!(
+            r#"listen_pg_addr = 'listen_pg_addr_VALUE'
+listen_http_addr = 'listen_http_addr_VALUE'
+checkpoint_distance = 'checkpoint_distance_VALUE'
+checkpoint_period = 'checkpoint_period_VALUE'
+gc_horizon = 'gc_horizon_VALUE'
+gc_period = 'gc_period_VALUE'
+open_mem_limit = 'open_mem_limit_VALUE'
+pg_distrib_dir = 'pg_distrib_dir_VALUE'
+auth_validation_public_key_path = 'auth_validation_public_key_path_VALUE'
+auth_type = 'auth_type_VALUE'
+remote_storage_max_concurrent_sync = 'remote_storage_max_concurrent_sync_VALUE'
+
+[remote_storage]
+bucket_name = 'bucket_name_VALUE'
+bucket_region = 'bucket_region_VALUE'
+"#,
+            toml_pretty_string
+        );
+
+        let params_from_serialized: CfgFileParams = toml::from_str(&toml_string)
+            .expect("Failed to deserialize the serialization result of the config");
+        let params_from_serialized_pretty: CfgFileParams = toml::from_str(&toml_pretty_string)
+            .expect("Failed to deserialize the prettified serialization result of the config");
+
+        let mut expected_params = params;
+        expected_params.remote_storage = Some(RemoteStorage::AwsS3 {
+            bucket_name: "bucket_name_VALUE".to_string(),
+            bucket_region: "bucket_region_VALUE".to_string(),
+            access_key_id: None,
+            secret_access_key: None,
+        });
+        assert!(
+            params_from_serialized == expected_params,
+            "Expected the config without credentials in the end of a 'config -> serialize -> deserialize' chain"
+        );
+        assert!(
+            params_from_serialized_pretty == expected_params,
+            "Expected the config without credentials in the end of a 'config -> serialize pretty -> deserialize' chain"
+        );
+    }
+}

pageserver/src/branches.rs

@@ -4,7 +4,7 @@
 // TODO: move all paths construction to conf impl
 //
 
-use anyhow::{bail, ensure, Context, Result};
+use anyhow::{bail, Context, Result};
 use postgres_ffi::ControlFileData;
 use serde::{Deserialize, Serialize};
 use std::{
@@ -14,25 +14,90 @@ use std::{
     str::FromStr,
     sync::Arc,
 };
+use tracing::*;
+
+use zenith_utils::crashsafe_dir;
+use zenith_utils::logging;
+use zenith_utils::lsn::Lsn;
 use zenith_utils::zid::{ZTenantId, ZTimelineId};
 
-use log::*;
-use zenith_utils::lsn::Lsn;
-
-use crate::logger;
-use crate::object_repository::ObjectRepository;
-use crate::page_cache;
-use crate::restore_local_repo;
+use crate::tenant_mgr;
 use crate::walredo::WalRedoManager;
-use crate::{repository::Repository, PageServerConf, RepositoryFormat};
+use crate::CheckpointConfig;
+use crate::{repository::Repository, PageServerConf};
+use crate::{restore_local_repo, LOG_FILE_NAME};
 
 #[derive(Serialize, Deserialize, Clone)]
 pub struct BranchInfo {
     pub name: String,
+    #[serde(with = "hex")]
     pub timeline_id: ZTimelineId,
-    pub latest_valid_lsn: Option<Lsn>,
+    pub latest_valid_lsn: Lsn,
     pub ancestor_id: Option<String>,
     pub ancestor_lsn: Option<String>,
+    pub current_logical_size: usize,
+    pub current_logical_size_non_incremental: Option<usize>,
+}
+
+impl BranchInfo {
+    pub fn from_path<T: AsRef<Path>>(
+        path: T,
+        conf: &PageServerConf,
+        tenantid: &ZTenantId,
+        repo: &Arc<dyn Repository>,
+        include_non_incremental_logical_size: bool,
+    ) -> Result<Self> {
+        let name = path
+            .as_ref()
+            .file_name()
+            .unwrap()
+            .to_str()
+            .unwrap()
+            .to_string();
+        let timeline_id = std::fs::read_to_string(path)?.parse::<ZTimelineId>()?;
+
+        let timeline = repo.get_timeline(timeline_id)?;
+
+        let ancestor_path = conf.ancestor_path(&timeline_id, tenantid);
+        let mut ancestor_id: Option<String> = None;
+        let mut ancestor_lsn: Option<String> = None;
+
+        if ancestor_path.exists() {
+            let ancestor = std::fs::read_to_string(ancestor_path)?;
+            let mut strings = ancestor.split('@');
+
+            ancestor_id = Some(
+                strings
+                    .next()
+                    .with_context(|| "wrong branch ancestor point in time format")?
+                    .to_owned(),
+            );
+            ancestor_lsn = Some(
+                strings
+                    .next()
+                    .with_context(|| "wrong branch ancestor point in time format")?
+                    .to_owned(),
+            );
+        }
+
+        // non incremental size calculation can be heavy, so let it be optional
+        // needed for tests to check size calculation
+        let current_logical_size_non_incremental = include_non_incremental_logical_size
+            .then(|| {
+                timeline.get_current_logical_size_non_incremental(timeline.get_last_record_lsn())
+            })
+            .transpose()?;
+
+        Ok(BranchInfo {
+            name,
+            timeline_id,
+            latest_valid_lsn: timeline.get_last_record_lsn(),
+            ancestor_id,
+            ancestor_lsn,
+            current_logical_size: timeline.get_current_logical_size(),
+            current_logical_size_non_incremental,
+        })
+    }
 }
 
 #[derive(Debug, Clone, Copy)]
@@ -43,20 +108,27 @@ pub struct PointInTime {
 
 pub fn init_pageserver(conf: &'static PageServerConf, create_tenant: Option<&str>) -> Result<()> {
     // Initialize logger
-    let (_scope_guard, _log_file) = logger::init_logging(&conf, "pageserver.log")?;
-    let _log_guard = slog_stdlog::init()?;
+    // use true as daemonize parameter because otherwise we pollute zenith cli output with a few pages long output of info messages
+    let _log_file = logging::init(LOG_FILE_NAME, true)?;
+
+    // We don't use the real WAL redo manager, because we don't want to spawn the WAL redo
+    // process during repository initialization.
+    //
+    // FIXME: That caused trouble, because the WAL redo manager spawned a thread that launched
+    // initdb in the background, and it kept running even after the "zenith init" had exited.
+    // In tests, we started the  page server immediately after that, so that initdb was still
+    // running in the background, and we failed to run initdb again in the same directory. This
+    // has been solved for the rapid init+start case now, but the general race condition remains
+    // if you restart the server quickly. The WAL redo manager doesn't use a separate thread
+    // anymore, but I think that could still happen.
+    let dummy_redo_mgr = Arc::new(crate::walredo::DummyRedoManager {});
 
     if let Some(tenantid) = create_tenant {
         let tenantid = ZTenantId::from_str(tenantid)?;
         println!("initializing tenantid {}", tenantid);
-        create_repo(
-            conf,
-            tenantid,
-            Arc::new(crate::walredo::DummyRedoManager {}),
-        )
-        .with_context(|| "failed to create repo")?;
+        create_repo(conf, tenantid, dummy_redo_mgr).with_context(|| "failed to create repo")?;
     }
-    fs::create_dir_all(conf.tenants_path())?;
+    crashsafe_dir::create_dir_all(conf.tenants_path())?;
 
     println!("pageserver init succeeded");
     Ok(())
@@ -73,50 +145,28 @@ pub fn create_repo(
     }
 
     // top-level dir may exist if we are creating it through CLI
-    fs::create_dir_all(&repo_dir)
+    crashsafe_dir::create_dir_all(&repo_dir)
         .with_context(|| format!("could not create directory {}", repo_dir.display()))?;
 
-    // Note: this `info!(...)` macro comes from `log` crate
-    info!("standard logging redirected to slog");
-
-    fs::create_dir(conf.timelines_path(&tenantid))?;
-    fs::create_dir_all(conf.branches_path(&tenantid))?;
-    fs::create_dir_all(conf.tags_path(&tenantid))?;
+    crashsafe_dir::create_dir(conf.timelines_path(&tenantid))?;
+    crashsafe_dir::create_dir_all(conf.branches_path(&tenantid))?;
+    crashsafe_dir::create_dir_all(conf.tags_path(&tenantid))?;
 
     info!("created directory structure in {}", repo_dir.display());
 
     let tli = create_timeline(conf, None, &tenantid)?;
 
-    // We don't use page_cache here, because we don't want to spawn the WAL redo thread during
-    // repository initialization.
-    //
-    // FIXME: That caused trouble, because the WAL redo thread launched initdb in the background,
-    // and it kept running even after the "zenith init" had exited. In tests, we started the
-    // page server immediately after that, so that initdb was still running in the background,
-    // and we failed to run initdb again in the same directory. This has been solved for the
-    // rapid init+start case now, but the general race condition remains if you restart the
-    // server quickly.
-    let repo: Arc<dyn Repository + Sync + Send> =
-        match conf.repository_format {
-            RepositoryFormat::Layered => Arc::new(
-                crate::layered_repository::LayeredRepository::new(conf, wal_redo_manager, tenantid),
-            ),
-            RepositoryFormat::RocksDb => {
-                let obj_store = crate::rocksdb_storage::RocksObjectStore::create(conf, &tenantid)?;
-
-                Arc::new(ObjectRepository::new(
-                    conf,
-                    Arc::new(obj_store),
-                    wal_redo_manager,
-                    tenantid,
-                ))
-            }
-        };
+    let repo = Arc::new(crate::layered_repository::LayeredRepository::new(
+        conf,
+        wal_redo_manager,
+        tenantid,
+        false,
+    ));
 
     // Load data into pageserver
     // TODO To implement zenith import we need to
     //      move data loading out of create_repo()
-    bootstrap_timeline(conf, tenantid, tli, &*repo)?;
+    bootstrap_timeline(conf, tenantid, tli, repo.as_ref())?;
 
     Ok(repo)
 }
@@ -131,17 +181,20 @@ fn get_lsn_from_controlfile(path: &Path) -> Result<Lsn> {
     Ok(Lsn(lsn))
 }
 
-// Create the cluster temporarily in a initdbpath directory inside the repository
+// Create the cluster temporarily in 'initdbpath' directory inside the repository
 // to get bootstrap data for timeline initialization.
 //
 fn run_initdb(conf: &'static PageServerConf, initdbpath: &Path) -> Result<()> {
-    info!("running initdb... ");
+    info!("running initdb in {}... ", initdbpath.display());
 
     let initdb_path = conf.pg_bin_dir().join("initdb");
     let initdb_output = Command::new(initdb_path)
         .args(&["-D", initdbpath.to_str().unwrap()])
         .args(&["-U", &conf.superuser])
         .arg("--no-instructions")
+        // This is only used for a temporary installation that is deleted shortly after,
+        // so no need to fsync it
+        .arg("--no-sync")
         .env_clear()
         .env("LD_LIBRARY_PATH", conf.pg_lib_dir().to_str().unwrap())
         .env("DYLD_LIBRARY_PATH", conf.pg_lib_dir().to_str().unwrap())
@@ -154,7 +207,6 @@ fn run_initdb(conf: &'static PageServerConf, initdbpath: &Path) -> Result<()> {
             String::from_utf8_lossy(&initdb_output.stderr)
         );
     }
-    info!("initdb succeeded");
 
     Ok(())
 }
@@ -169,21 +221,25 @@ fn bootstrap_timeline(
     tli: ZTimelineId,
     repo: &dyn Repository,
 ) -> Result<()> {
+    let _enter = info_span!("bootstrapping", timeline = %tli, tenant = %tenantid).entered();
+
     let initdb_path = conf.tenant_path(&tenantid).join("tmp");
 
     // Init temporarily repo to get bootstrap data
     run_initdb(conf, &initdb_path)?;
     let pgdata_path = initdb_path;
 
-    let lsn = get_lsn_from_controlfile(&pgdata_path)?;
+    let lsn = get_lsn_from_controlfile(&pgdata_path)?.align();
 
-    info!("bootstrap_timeline {:?} at lsn {}", pgdata_path, lsn);
-
-    let timeline = repo.create_empty_timeline(tli, lsn)?;
-    restore_local_repo::import_timeline_from_postgres_datadir(&pgdata_path, &*timeline, lsn)?;
-
-    let wal_dir = pgdata_path.join("pg_wal");
-    restore_local_repo::import_timeline_wal(&wal_dir, &*timeline, timeline.get_last_record_lsn())?;
+    // Import the contents of the data directory at the initial checkpoint
+    // LSN, and any WAL after that.
+    let timeline = repo.create_empty_timeline(tli)?;
+    restore_local_repo::import_timeline_from_postgres_datadir(
+        &pgdata_path,
+        timeline.writer().as_ref(),
+        lsn,
+    )?;
+    timeline.checkpoint(CheckpointConfig::Forced)?;
 
     println!(
         "created initial timeline {} timeline.lsn {}",
@@ -201,20 +257,12 @@ fn bootstrap_timeline(
     Ok(())
 }
 
-pub(crate) fn get_tenants(conf: &PageServerConf) -> Result<Vec<String>> {
-    let tenants_dir = conf.tenants_path();
-
-    std::fs::read_dir(&tenants_dir)?
-        .map(|dir_entry_res| {
-            let dir_entry = dir_entry_res?;
-            ensure!(dir_entry.file_type()?.is_dir());
-            Ok(dir_entry.file_name().to_str().unwrap().to_owned())
-        })
-        .collect()
-}
-
-pub(crate) fn get_branches(conf: &PageServerConf, tenantid: &ZTenantId) -> Result<Vec<BranchInfo>> {
-    let repo = page_cache::get_repository_for_tenant(tenantid)?;
+pub(crate) fn get_branches(
+    conf: &PageServerConf,
+    tenantid: &ZTenantId,
+    include_non_incremental_logical_size: bool,
+) -> Result<Vec<BranchInfo>> {
+    let repo = tenant_mgr::get_repository_for_tenant(*tenantid)?;
 
     // Each branch has a corresponding record (text file) in the refs/branches
     // with timeline_id.
@@ -223,43 +271,13 @@ pub(crate) fn get_branches(conf: &PageServerConf, tenantid: &ZTenantId) -> Resul
     std::fs::read_dir(&branches_dir)?
         .map(|dir_entry_res| {
             let dir_entry = dir_entry_res?;
-            let name = dir_entry.file_name().to_str().unwrap().to_string();
-            let timeline_id = std::fs::read_to_string(dir_entry.path())?.parse::<ZTimelineId>()?;
-
-            let latest_valid_lsn = repo
-                .get_timeline(timeline_id)
-                .map(|timeline| timeline.get_last_valid_lsn())
-                .ok();
-
-            let ancestor_path = conf.ancestor_path(&timeline_id, tenantid);
-            let mut ancestor_id: Option<String> = None;
-            let mut ancestor_lsn: Option<String> = None;
-
-            if ancestor_path.exists() {
-                let ancestor = std::fs::read_to_string(ancestor_path)?;
-                let mut strings = ancestor.split('@');
-
-                ancestor_id = Some(
-                    strings
-                        .next()
-                        .with_context(|| "wrong branch ancestor point in time format")?
-                        .to_owned(),
-                );
-                ancestor_lsn = Some(
-                    strings
-                        .next()
-                        .with_context(|| "wrong branch ancestor point in time format")?
-                        .to_owned(),
-                );
-            }
-
-            Ok(BranchInfo {
-                name,
-                timeline_id,
-                latest_valid_lsn,
-                ancestor_id,
-                ancestor_lsn,
-            })
+            BranchInfo::from_path(
+                dir_entry.path(),
+                conf,
+                tenantid,
+                &repo,
+                include_non_incremental_logical_size,
+            )
         })
         .collect()
 }
@@ -270,21 +288,36 @@ pub(crate) fn create_branch(
     startpoint_str: &str,
     tenantid: &ZTenantId,
 ) -> Result<BranchInfo> {
-    let repo = page_cache::get_repository_for_tenant(tenantid)?;
+    let repo = tenant_mgr::get_repository_for_tenant(*tenantid)?;
 
     if conf.branch_path(branchname, tenantid).exists() {
         anyhow::bail!("branch {} already exists", branchname);
     }
 
     let mut startpoint = parse_point_in_time(conf, startpoint_str, tenantid)?;
-
+    let timeline = repo.get_timeline(startpoint.timelineid)?;
     if startpoint.lsn == Lsn(0) {
         // Find end of WAL on the old timeline
-        let end_of_wal = repo
-            .get_timeline(startpoint.timelineid)?
-            .get_last_record_lsn();
-        println!("branching at end of WAL: {}", end_of_wal);
+        let end_of_wal = timeline.get_last_record_lsn();
+        info!("branching at end of WAL: {}", end_of_wal);
         startpoint.lsn = end_of_wal;
+    } else {
+        // Wait for the WAL to arrive and be processed on the parent branch up
+        // to the requested branch point. The repository code itself doesn't
+        // require it, but if we start to receive WAL on the new timeline,
+        // decoding the new WAL might need to look up previous pages, relation
+        // sizes etc. and that would get confused if the previous page versions
+        // are not in the repository yet.
+        timeline.wait_lsn(startpoint.lsn)?;
+    }
+    startpoint.lsn = startpoint.lsn.align();
+    if timeline.get_start_lsn() > startpoint.lsn {
+        anyhow::bail!(
+            "invalid startpoint {} for the branch {}: less than timeline start {}",
+            startpoint.lsn,
+            branchname,
+            timeline.get_start_lsn()
+        );
     }
 
     // create a new timeline directory for it
@@ -297,14 +330,16 @@ pub(crate) fn create_branch(
     // FIXME: there's a race condition, if you create a branch with the same
     // name concurrently.
     let data = newtli.to_string();
-    fs::write(conf.branch_path(&branchname, tenantid), data)?;
+    fs::write(conf.branch_path(branchname, tenantid), data)?;
 
     Ok(BranchInfo {
         name: branchname.to_string(),
         timeline_id: newtli,
-        latest_valid_lsn: Some(startpoint.lsn),
+        latest_valid_lsn: startpoint.lsn,
         ancestor_id: None,
         ancestor_lsn: None,
+        current_logical_size: 0,
+        current_logical_size_non_incremental: Some(0),
     })
 }
 
@@ -346,21 +381,21 @@ fn parse_point_in_time(
 
     // Check if it's a tag
     if lsn.is_none() {
-        let tagpath = conf.tag_path(name, &tenantid);
+        let tagpath = conf.tag_path(name, tenantid);
         if tagpath.exists() {
             let pointstr = fs::read_to_string(tagpath)?;
 
-            return parse_point_in_time(conf, &pointstr, &tenantid);
+            return parse_point_in_time(conf, &pointstr, tenantid);
         }
     }
 
     // Check if it's a branch
     // Check if it's branch @ LSN
-    let branchpath = conf.branch_path(name, &tenantid);
+    let branchpath = conf.branch_path(name, tenantid);
     if branchpath.exists() {
         let pointstr = fs::read_to_string(branchpath)?;
 
-        let mut result = parse_point_in_time(conf, &pointstr, &tenantid)?;
+        let mut result = parse_point_in_time(conf, &pointstr, tenantid)?;
 
         result.lsn = lsn.unwrap_or(Lsn(0));
         return Ok(result);
@@ -369,7 +404,7 @@ fn parse_point_in_time(
     // Check if it's a timelineid
     // Check if it's timelineid @ LSN
     if let Ok(timelineid) = ZTimelineId::from_str(name) {
-        let tlipath = conf.timeline_path(&timelineid, &tenantid);
+        let tlipath = conf.timeline_path(&timelineid, tenantid);
         if tlipath.exists() {
             return Ok(PointInTime {
                 timelineid,
@@ -393,7 +428,6 @@ fn create_timeline(
     let timelinedir = conf.timeline_path(&timelineid, tenantid);
 
     fs::create_dir(&timelinedir)?;
-    fs::create_dir(&timelinedir.join("wal"))?;
 
     if let Some(ancestor) = ancestor {
         let data = format!("{}@{}", ancestor.timelineid, ancestor.lsn);

pageserver/src/http/mod.rs

@@ -0,0 +1,3 @@
+pub mod models;
+pub mod routes;
+pub use routes::make_router;

pageserver/src/http/models.rs

@@ -0,0 +1,17 @@
+use serde::{Deserialize, Serialize};
+
+use crate::ZTenantId;
+
+#[derive(Serialize, Deserialize)]
+pub struct BranchCreateRequest {
+    #[serde(with = "hex")]
+    pub tenant_id: ZTenantId,
+    pub name: String,
+    pub start_point: String,
+}
+
+#[derive(Serialize, Deserialize)]
+pub struct TenantCreateRequest {
+    #[serde(with = "hex")]
+    pub tenant_id: ZTenantId,
+}

pageserver/src/http/openapi_spec.yml

@@ -0,0 +1,310 @@
+openapi: "3.0.2"
+info:
+  title: Page Server API
+  version: "1.0"
+servers:
+  - url: ""
+paths:
+  /v1/status:
+    description: Healthcheck endpoint
+    get:
+      description: Healthcheck
+      security: []
+      responses:
+        "200":
+          description: OK
+          content:
+            application/json:
+              schema:
+                type: object
+  /v1/branch/{tenant_id}:
+    parameters:
+      - name: tenant_id
+        in: path
+        required: true
+        schema:
+          type: string
+          format: hex
+      - name: include-non-incremental-logical-size
+        in: query
+        schema:
+          type: string
+          description: Controls calculation of current_logical_size_non_incremental
+    get:
+      description: Get branches for tenant
+      responses:
+        "200":
+          description: BranchInfo
+          content:
+            application/json:
+              schema:
+                type: array
+                items:
+                  $ref: "#/components/schemas/BranchInfo"
+        "400":
+          description: Error when no tenant id found in path
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Error"
+        "401":
+          description: Unauthorized Error
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/UnauthorizedError"
+        "403":
+          description: Forbidden Error
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/ForbiddenError"
+        "500":
+          description: Generic operation error
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Error"
+  /v1/branch/{tenant_id}/{branch_name}:
+    parameters:
+      - name: tenant_id
+        in: path
+        required: true
+        schema:
+          type: string
+          format: hex
+      - name: branch_name
+        in: path
+        required: true
+        schema:
+          type: string
+      - name: include-non-incremental-logical-size
+        in: query
+        schema:
+          type: string
+          description: Controls calculation of current_logical_size_non_incremental
+    get:
+      description: Get branches for tenant
+      responses:
+        "200":
+          description: BranchInfo
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/BranchInfo"
+        "400":
+          description: Error when no tenant id found in path or no branch name
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Error"
+        "401":
+          description: Unauthorized Error
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/UnauthorizedError"
+        "403":
+          description: Forbidden Error
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/ForbiddenError"
+        "500":
+          description: Generic operation error
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Error"
+  /v1/branch/:
+    post:
+      description: Create branch
+      requestBody:
+        content:
+          application/json:
+            schema:
+              type: object
+              required:
+                - "tenant_id"
+                - "name"
+                - "start_point"
+              properties:
+                tenant_id:
+                  type: string
+                  format: hex
+                name:
+                  type: string
+                start_point:
+                  type: string
+      responses:
+        "201":
+          description: BranchInfo
+          content:
+            application/json:
+              schema:
+                type: array
+                items:
+                  $ref: "#/components/schemas/BranchInfo"
+        "400":
+          description: Malformed branch create request
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Error"
+        "401":
+          description: Unauthorized Error
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/UnauthorizedError"
+        "403":
+          description: Forbidden Error
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/ForbiddenError"
+        "500":
+          description: Generic operation error
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Error"
+  /v1/tenant/:
+    get:
+      description: Get tenants list
+      responses:
+        "200":
+          description: TenantInfo
+          content:
+            application/json:
+              schema:
+                type: array
+                items:
+                  $ref: "#/components/schemas/TenantInfo"
+        "401":
+          description: Unauthorized Error
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/UnauthorizedError"
+        "403":
+          description: Forbidden Error
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/ForbiddenError"
+        "500":
+          description: Generic operation error
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Error"
+    post:
+      description: Create tenant
+      requestBody:
+        content:
+          application/json:
+            schema:
+              type: object
+              required:
+                - "tenant_id"
+              properties:
+                tenant_id:
+                  type: string
+                  format: hex
+      responses:
+        "201":
+          description: CREATED
+          content:
+            application/json:
+              schema:
+                type: array
+                items:
+                  type: string
+        "400":
+          description: Malformed tenant create request
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Error"
+        "401":
+          description: Unauthorized Error
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/UnauthorizedError"
+        "403":
+          description: Forbidden Error
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/ForbiddenError"
+        "500":
+          description: Generic operation error
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Error"
+
+components:
+  securitySchemes:
+    JWT:
+      type: http
+      scheme: bearer
+      bearerFormat: JWT
+  schemas:
+    TenantInfo:
+      type: object
+      required:
+        - id
+        - state
+      properties:
+        id:
+          type: string
+        state:
+          type: string
+    BranchInfo:
+      type: object
+      required:
+        - name
+        - timeline_id
+        - latest_valid_lsn
+        - current_logical_size
+      properties:
+        name:
+          type: string
+        timeline_id:
+          type: string
+          format: hex
+        ancestor_id:
+          type: string
+        ancestor_lsn:
+          type: string
+        current_logical_size:
+          type: integer
+        current_logical_size_non_incremental:
+          type: integer
+    Error:
+      type: object
+      required:
+        - msg
+      properties:
+        msg:
+          type: string
+    UnauthorizedError:
+      type: object
+      required:
+        - msg
+      properties:
+        msg:
+          type: string
+    ForbiddenError:
+      type: object
+      required:
+        - msg
+      properties:
+        msg:
+          type: string
+
+security:
+  - JWT: []

pageserver/src/http/routes.rs

@@ -0,0 +1,211 @@
+use std::sync::Arc;
+
+use anyhow::Result;
+use hyper::header;
+use hyper::StatusCode;
+use hyper::{Body, Request, Response, Uri};
+use routerify::{ext::RequestExt, RouterBuilder};
+use tracing::*;
+use zenith_utils::auth::JwtAuth;
+use zenith_utils::http::endpoint::attach_openapi_ui;
+use zenith_utils::http::endpoint::auth_middleware;
+use zenith_utils::http::endpoint::check_permission;
+use zenith_utils::http::error::ApiError;
+use zenith_utils::http::{
+    endpoint,
+    error::HttpErrorBody,
+    json::{json_request, json_response},
+    request::get_request_param,
+    request::parse_request_param,
+};
+
+use super::models::BranchCreateRequest;
+use super::models::TenantCreateRequest;
+use crate::branches::BranchInfo;
+use crate::{branches, tenant_mgr, PageServerConf, ZTenantId};
+
+#[derive(Debug)]
+struct State {
+    conf: &'static PageServerConf,
+    auth: Option<Arc<JwtAuth>>,
+    allowlist_routes: Vec<Uri>,
+}
+
+impl State {
+    fn new(conf: &'static PageServerConf, auth: Option<Arc<JwtAuth>>) -> Self {
+        let allowlist_routes = ["/v1/status", "/v1/doc", "/swagger.yml"]
+            .iter()
+            .map(|v| v.parse().unwrap())
+            .collect::<Vec<_>>();
+        Self {
+            conf,
+            auth,
+            allowlist_routes,
+        }
+    }
+}
+
+#[inline(always)]
+fn get_state(request: &Request<Body>) -> &State {
+    request
+        .data::<Arc<State>>()
+        .expect("unknown state type")
+        .as_ref()
+}
+
+#[inline(always)]
+fn get_config(request: &Request<Body>) -> &'static PageServerConf {
+    get_state(request).conf
+}
+
+// healthcheck handler
+async fn status_handler(_: Request<Body>) -> Result<Response<Body>, ApiError> {
+    Ok(Response::builder()
+        .status(StatusCode::OK)
+        .header(header::CONTENT_TYPE, "application/json")
+        .body(Body::from("{}"))
+        .map_err(ApiError::from_err)?)
+}
+
+async fn branch_create_handler(mut request: Request<Body>) -> Result<Response<Body>, ApiError> {
+    let request_data: BranchCreateRequest = json_request(&mut request).await?;
+
+    check_permission(&request, Some(request_data.tenant_id))?;
+
+    let response_data = tokio::task::spawn_blocking(move || {
+        let _enter = info_span!("/branch_create", name = %request_data.name, tenant = %request_data.tenant_id, startpoint=%request_data.start_point).entered();
+        branches::create_branch(
+            get_config(&request),
+            &request_data.name,
+            &request_data.start_point,
+            &request_data.tenant_id,
+        )
+    })
+    .await
+    .map_err(ApiError::from_err)??;
+    Ok(json_response(StatusCode::CREATED, response_data)?)
+}
+
+// Gate non incremental logical size calculation behind a flag
+// after pgbench -i -s100 calculation took 28ms so if multiplied by the number of timelines
+// and tenants it can take noticeable amount of time. Also the value currently used only in tests
+fn get_include_non_incremental_logical_size(request: &Request<Body>) -> bool {
+    request
+        .uri()
+        .query()
+        .map(|v| {
+            url::form_urlencoded::parse(v.as_bytes())
+                .into_owned()
+                .any(|(param, _)| param == "include-non-incremental-logical-size")
+        })
+        .unwrap_or(false)
+}
+
+async fn branch_list_handler(request: Request<Body>) -> Result<Response<Body>, ApiError> {
+    let tenantid: ZTenantId = parse_request_param(&request, "tenant_id")?;
+
+    let include_non_incremental_logical_size = get_include_non_incremental_logical_size(&request);
+
+    check_permission(&request, Some(tenantid))?;
+
+    let response_data = tokio::task::spawn_blocking(move || {
+        let _enter = info_span!("branch_list", tenant = %tenantid).entered();
+        crate::branches::get_branches(
+            get_config(&request),
+            &tenantid,
+            include_non_incremental_logical_size,
+        )
+    })
+    .await
+    .map_err(ApiError::from_err)??;
+    Ok(json_response(StatusCode::OK, response_data)?)
+}
+
+async fn branch_detail_handler(request: Request<Body>) -> Result<Response<Body>, ApiError> {
+    let tenantid: ZTenantId = parse_request_param(&request, "tenant_id")?;
+    let branch_name: String = get_request_param(&request, "branch_name")?.to_string();
+    let conf = get_state(&request).conf;
+    let path = conf.branch_path(&branch_name, &tenantid);
+
+    let include_non_incremental_logical_size = get_include_non_incremental_logical_size(&request);
+
+    let response_data = tokio::task::spawn_blocking(move || {
+        let _enter = info_span!("branch_detail", tenant = %tenantid, branch=%branch_name).entered();
+        let repo = tenant_mgr::get_repository_for_tenant(tenantid)?;
+        BranchInfo::from_path(
+            path,
+            conf,
+            &tenantid,
+            &repo,
+            include_non_incremental_logical_size,
+        )
+    })
+    .await
+    .map_err(ApiError::from_err)??;
+
+    Ok(json_response(StatusCode::OK, response_data)?)
+}
+
+async fn tenant_list_handler(request: Request<Body>) -> Result<Response<Body>, ApiError> {
+    // check for management permission
+    check_permission(&request, None)?;
+
+    let response_data = tokio::task::spawn_blocking(move || {
+        let _enter = info_span!("tenant_list").entered();
+        crate::tenant_mgr::list_tenants()
+    })
+    .await
+    .map_err(ApiError::from_err)??;
+
+    Ok(json_response(StatusCode::OK, response_data)?)
+}
+
+async fn tenant_create_handler(mut request: Request<Body>) -> Result<Response<Body>, ApiError> {
+    // check for management permission
+    check_permission(&request, None)?;
+
+    let request_data: TenantCreateRequest = json_request(&mut request).await?;
+
+    let response_data = tokio::task::spawn_blocking(move || {
+        let _enter = info_span!("tenant_create", tenant = %request_data.tenant_id).entered();
+        tenant_mgr::create_repository_for_tenant(get_config(&request), request_data.tenant_id)
+    })
+    .await
+    .map_err(ApiError::from_err)??;
+    Ok(json_response(StatusCode::CREATED, response_data)?)
+}
+
+async fn handler_404(_: Request<Body>) -> Result<Response<Body>, ApiError> {
+    json_response(
+        StatusCode::NOT_FOUND,
+        HttpErrorBody::from_msg("page not found".to_owned()),
+    )
+}
+
+pub fn make_router(
+    conf: &'static PageServerConf,
+    auth: Option<Arc<JwtAuth>>,
+) -> RouterBuilder<hyper::Body, ApiError> {
+    let spec = include_bytes!("openapi_spec.yml");
+    let mut router = attach_openapi_ui(endpoint::make_router(), spec, "/swagger.yml", "/v1/doc");
+    if auth.is_some() {
+        router = router.middleware(auth_middleware(|request| {
+            let state = get_state(request);
+            if state.allowlist_routes.contains(request.uri()) {
+                None
+            } else {
+                state.auth.as_deref()
+            }
+        }))
+    }
+
+    router
+        .data(Arc::new(State::new(conf, auth)))
+        .get("/v1/status", status_handler)
+        .get("/v1/branch/:tenant_id", branch_list_handler)
+        .get("/v1/branch/:tenant_id/:branch_name", branch_detail_handler)
+        .post("/v1/branch", branch_create_handler)
+        .get("/v1/tenant", tenant_list_handler)
+        .post("/v1/tenant", tenant_create_handler)
+        .any(handler_404)
+}

pageserver/src/layered_repository/README.md

@@ -4,52 +4,109 @@ The on-disk format is based on immutable files. The page server
 receives a stream of incoming WAL, parses the WAL records to determine
 which pages they apply to, and accumulates the incoming changes in
 memory. Every now and then, the accumulated changes are written out to
-new files.
+new immutable files. This process is called checkpointing. Old versions
+of on-disk files that are not needed by any timeline are removed by GC
+process.
 
-The files are called "snapshot files". Each snapshot file corresponds
-to one 10 MB slice of a PostgreSQL relation fork. The snapshot files
+# Terms used in layered repository
+
+- Relish - one PostgreSQL relation or similarly treated file.
+- Segment - one slice of a Relish that is stored in a LayeredTimeline.
+- Layer -  specific version of a relish Segment in a range of LSNs.
+
+Layers can be InMemory or OnDisk:
+- InMemory layer is not durably stored and needs to rebuild from WAL on pageserver start.
+- OnDisk layer is durably stored.
+
+OnDisk layers can be Image or Delta:
+- ImageLayer represents an image or a snapshot of a segment at one particular LSN.
+- DeltaLayer represents a collection of WAL records or page images in a range of LSNs.
+
+Dropped segments are always represented on disk by DeltaLayer.
+
+LSN range defined by start_lsn and end_lsn:
+- start_lsn is inclusive.
+- end_lsn is exclusive.
+
+For an open in-memory layer, the end_lsn is MAX_LSN. For a frozen
+in-memory layer or a delta layer, it is a valid end bound. An image
+layer represents snapshot at one LSN, so end_lsn is always the
+snapshot LSN + 1
+
+Layers can be open or historical:
+- Open layer is a writeable one. Only InMemory layer can be open.
+FIXME: If open layer is dropped, it is not writeable, so it should be turned into historical, 
+but now it is not implemented - see bug #569.
+- Historical layer is the one that cannot be modified anymore. Now only OnDisk layers can be historical.
+
+- LayerMap - a map that tracks what layers exist for all the relishes in a timeline.
+
+LayerMap consists of two data structures:
+- segs - All the layers keyed by segment tag
+- open_layers - data structure that hold all open layers ordered by oldest_pending_lsn for quick access during checkpointing. oldest_pending_lsn is the LSN of the oldest page version stored in this layer.
+
+All operations that update InMemory Layers should update both structures to keep them up-to-date.
+
+- LayeredTimeline - implements Timeline interface.
+
+All methods of LayeredTimeline are aware of its ancestors and return data taking them into account.
+TODO: Are there any exceptions to this?
+For example, timeline.list_rels(lsn) will return all segments that are visible in this timeline at the LSN,
+including ones that were not modified in this timeline and thus don't have a layer in the timeline's LayerMap.
+
+TODO:
+Describe GC and checkpoint interval settings.
+
+# Layer files (On-disk layers)
+
+The files are called "layer files". Each layer file corresponds
+to one RELISH_SEG_SIZE slice of a PostgreSQL relation fork or
+non-rel file in a range of LSNs. The layer files
 for each timeline are stored in the timeline's subdirectory under
 .zenith/tenants/<tenantid>/timelines.
 
-The files are named like this:
+There are two kind of layer file: base images, and deltas. A base
+image file contains a layer of a segment as it was at one LSN,
+whereas a delta file contains modifications to a segment - mostly in
+the form of WAL records - in a range of LSN
+
+base image file:
+
+    rel_<spcnode>_<dbnode>_<relnode>_<forknum>_<segno>_<start LSN>
+
+delta file:
 
     rel_<spcnode>_<dbnode>_<relnode>_<forknum>_<segno>_<start LSN>_<end LSN>
 
 For example:
 
+    rel_1663_13990_2609_0_10_000000000169C348
     rel_1663_13990_2609_0_10_000000000169C348_0000000001702000
 
-Some non-relation files are also stored in repository. For example,
-a CLOG segment would be named like this:
+In addition to the relations, with "rel_*" prefix, we use the same
+format for storing various smaller files from the PostgreSQL data
+directory. They will use different suffixes and the naming scheme up
+to the LSNs vary. The Zenith source code uses the term "relish" to
+mean "a relation, or other file that's treated like a relation in the
+storage" For example, a base image of a CLOG segment would be named
+like this:
 
-    pg_xact_0000_0_00000000198B06B0_00000000198C2550
+    pg_xact_0000_0_00000000198B06B0
 
 There is no difference in how the relation and non-relation files are
 managed, except that the first part of file names is different.
 Internally, the relations and non-relation files that are managed in
 the versioned store are together called "relishes".
 
-Each snapshot file contains a full snapshot, that is, full copy of all
-pages in the relation, as of the "start LSN". It also contains all WAL
-records applicable to the relation between the start and end
-LSNs. With this information, the page server can reconstruct any page
-version of the relation in the LSN range.
-
-If a file has been dropped, the last snapshot file for it is created
+If a file has been dropped, the last layer file for it is created
 with the _DROPPED suffix, e.g.
 
     rel_1663_13990_2609_0_10_000000000169C348_0000000001702000_DROPPED
 
-In addition to the relations, with "rel_*" prefix, we use the same
-format for storing various smaller files from the PostgreSQL data
-directory. They will use different suffixes and the naming scheme
-up to the LSN range varies. The Zenith source code uses the term
-"relish" to mean "a relation, or other file that's treated like a
-relation in the storage"
 
 ## Notation used in this document
 
-The full path of a snapshot file looks like this:
+The full path of a delta file looks like this:
 
     .zenith/tenants/941ddc8604413b88b3d208bddf90396c/timelines/4af489b06af8eed9e27a841775616962/rel_1663_13990_2609_0_10_000000000169C348_0000000001702000
 
@@ -57,50 +114,68 @@ For simplicity, the examples below use a simplified notation for the
 paths.  The tenant ID is left out, the timeline ID is replaced with
 the human-readable branch name, and spcnode+dbnode+relnode+forkum+segno
 with a human-readable table name. The LSNs are also shorter. For
-example, a snapshot file for 'orders' table on 'main' branch, with LSN
-range 100-200 would be:
+example, a base image file at LSN 100 and a delta file between 100-200
+for 'orders' table on 'main' branch is represented like this:
 
+    main/orders_100
     main/orders_100_200
 
 
-# Creating snapshot files
+# Creating layer files
 
 Let's start with a simple example with a system that contains one
 branch called 'main' and two tables, 'orders' and 'customers'. The end
 of WAL is currently at LSN 250. In this starting situation, you would
-have two files on disk:
+have these files on disk:
 
+	main/orders_100
 	main/orders_100_200
+	main/orders_200
+	main/customers_100
 	main/customers_100_200
+	main/customers_200
 
 In addition to those files, the recent changes between LSN 200 and the
 end of WAL at 250 are kept in memory. If the page server crashes, the
 latest records between 200-250 need to be re-read from the WAL.
 
 Whenever enough WAL has been accumulated in memory, the page server
-writes out the changes in memory into new snapshot files. This process
+writes out the changes in memory into new layer files. This process
 is called "checkpointing" (not to be confused with the PostgreSQL
 checkpoints, that's a different thing). The page server only creates
-snapshot files for relations that have been modified since the last
+layer files for relations that have been modified since the last
 checkpoint. For example, if the current end of WAL is at LSN 450, and
 the last checkpoint happened at LSN 400 but there hasn't been any
 recent changes to 'customers' table, you would have these files on
 disk:
 
+	main/orders_100
 	main/orders_100_200
+	main/orders_200
 	main/orders_200_300
+	main/orders_300
 	main/orders_300_400
+	main/orders_400
+	main/customers_100
 	main/customers_100_200
+	main/customers_200
 
 If the customers table is modified later, a new file is created for it
 at the next checkpoint. The new file will cover the "gap" from the
-last snapshot file, so the LSN ranges are always contiguous:
+last layer file, so the LSN ranges are always contiguous:
 
+	main/orders_100
 	main/orders_100_200
+	main/orders_200
 	main/orders_200_300
+	main/orders_300
 	main/orders_300_400
+	main/orders_400
+	main/customers_100
 	main/customers_100_200
+	main/customers_200
 	main/customers_200_500
+	main/customers_500
 
 ## Reading page versions
 
@@ -109,29 +184,17 @@ page server needs to reconstruct the requested page, as it was at the
 requested LSN. To do that, the page server first checks the recent
 in-memory layer; if the requested page version is found there, it can
 be returned immediatedly without looking at the files on
-disk. Otherwise the page server needs to locate the snapshot file that
+disk. Otherwise the page server needs to locate the layer file that
 contains the requested page version.
 
 For example, if a request comes in for table 'orders' at LSN 250, the
 page server would load the 'main/orders_200_300' file into memory, and
 reconstruct and return the requested page from it, as it was at
-LSN 250. Because the snapshot file consists of a full image of the
+LSN 250. Because the layer file consists of a full image of the
 relation at the start LSN and the WAL, reconstructing the page
 involves replaying any WAL records applicable to the page between LSNs
 200-250, starting from the base image at LSN 200.
 
-A request at a file boundary can be satisfied using either file. For
-example, if there are two files on disk:
-
-	main/orders_100_200
-	main/orders_200_300
-
-And a request comes with LSN 200, either file can be used for it. It
-is better to use the later file, however, because it contains an
-already materialized version of all the pages at LSN 200. Using the
-first file, you would need to apply any WAL records between 100 and
-200 to reconstruct the requested page.
-
 # Multiple branches
 
 Imagine that a child branch is created at LSN 250:
@@ -145,16 +208,24 @@ Imagine that a child branch is created at LSN 250:
 Then, the 'orders' table is updated differently on the 'main' and
 'child' branches. You now have this situation on disk:
 
+    main/orders_100
     main/orders_100_200
+    main/orders_200
     main/orders_200_300
+    main/orders_300
     main/orders_300_400
+    main/orders_400
+    main/customers_100
     main/customers_100_200
+    main/customers_200
     child/orders_250_300
+    child/orders_300
     child/orders_300_400
+    child/orders_400
 
 Because the 'customers' table hasn't been modified on the child
 branch, there is no file for it there. If you request a page for it on
-the 'child' branch, the page server will not find any snapshot file
+the 'child' branch, the page server will not find any layer file
 for it in the 'child' directory, so it will recurse to look into the
 parent 'main' branch instead.
 
@@ -163,24 +234,34 @@ is linear, and the request's LSN identifies unambiguously which file
 you need to look at. For example, the history for the 'orders' table
 on the 'main' branch consists of these files:
 
+    main/orders_100
     main/orders_100_200
+    main/orders_200
     main/orders_200_300
+    main/orders_300
     main/orders_300_400
+    main/orders_400
 
 And from the 'child' branch's point of view, it consists of these
 files:
 
+    main/orders_100
     main/orders_100_200
+    main/orders_200
     main/orders_200_300
     child/orders_250_300
+    child/orders_300
     child/orders_300_400
+    child/orders_400
 
 The branch metadata includes the point where the child branch was
 created, LSN 250. If a page request comes with LSN 275, we read the
-page version from the 'child/orders_250_300' file. If the request LSN
-is 225, we read it from the 'main/orders_200_300' file instead.  The
-page versions between 250-300 in the 'main/orders_200_300' file are
-ignored when operating on the child branch.
+page version from the 'child/orders_250_300' file. We might also
+need to reconstruct the page version as it was at LSN 250, in order
+to replay the WAL up to LSN 275, using 'main/orders_200_300' and
+'main/orders_200'. The page versions between 250-300 in the
+'main/orders_200_300' file are ignored when operating on the child
+branch.
 
 Note: It doesn't make any difference if the child branch is created
 when the end of the main branch was at LSN 250, or later when the tip of
@@ -190,7 +271,7 @@ branch at a historic LSN, is how we support PITR in Zenith.
 
 # Garbage collection
 
-In this scheme, we keep creating new snapshot files over time. We also
+In this scheme, we keep creating new layer files over time. We also
 need a mechanism to remove old files that are no longer needed,
 because disk space isn't infinite.
 
@@ -204,18 +285,38 @@ Let's look at the single branch scenario again. Imagine that the end
 of the branch is LSN 525, so that the GC horizon is currently at
 525-150 = 375
 
+	main/orders_100
 	main/orders_100_200
+	main/orders_200
 	main/orders_200_300
+	main/orders_300
 	main/orders_300_400
+	main/orders_400
 	main/orders_400_500
+	main/orders_500
+	main/customers_100
 	main/customers_100_200
+	main/customers_200
 
-We can remove files 'main/orders_100_200' and 'main/orders_200_300',
-because the end LSNs of those files are older than GC horizon 375, and
-there are more recent snapshot files for the table. 'main/orders_300_400'
-and 'main/orders_400_500' are still within the horizon, so they must be
-retained. 'main/customers_100_200' is old enough, but it cannot be
-removed because there is no newer snapshot file for the table.
+We can remove the following files because the end LSNs of those files are
+older than GC horizon 375, and there are more recent layer files for the
+table:
+
+	main/orders_100       DELETE
+	main/orders_100_200   DELETE
+	main/orders_200       DELETE
+	main/orders_200_300   DELETE
+	main/orders_300       STILL NEEDED BY orders_300_400
+	main/orders_300_400   KEEP, NEWER THAN GC HORIZON
+	main/orders_400       .. 
+	main/orders_400_500   .. 
+	main/orders_500       .. 
+	main/customers_100      DELETE
+	main/customers_100_200  DELETE
+	main/customers_200      KEEP, NO NEWER VERSION
+
+'main/customers_100_200' is old enough, but it cannot be
+removed because there is no newer layer file for the table.
 
 Things get slightly more complicated with multiple branches. All of
 the above still holds, but in addition to recent files we must also
@@ -223,41 +324,47 @@ retain older shapshot files that are still needed by child branches.
 For example, if child branch is created at LSN 150, and the 'customers'
 table is updated on the branch, you would have these files:
 
-	main/orders_100_200
-	main/orders_200_300
-	main/orders_300_400
-	main/orders_400_500
-	main/customers_100_200
-	child/customers_150_300
+	main/orders_100        KEEP, NEEDED BY child BRANCH
+	main/orders_100_200    KEEP, NEEDED BY child BRANCH
+	main/orders_200        DELETE
+	main/orders_200_300    DELETE
+	main/orders_300        KEEP, NEWER THAN GC HORIZON
+	main/orders_300_400    KEEP, NEWER THAN GC HORIZON
+	main/orders_400        KEEP, NEWER THAN GC HORIZON
+	main/orders_400_500    KEEP, NEWER THAN GC HORIZON
+	main/orders_500        KEEP, NEWER THAN GC HORIZON
+	main/customers_100       DELETE
+	main/customers_100_200   DELETE
+	main/customers_200       KEEP, NO NEWER VERSION
+	child/customers_150_300  DELETE
+	child/customers_300      KEEP, NO NEWER VERSION
 
-In this situation, the 'main/orders_100_200' file cannot be removed,
-even though it is older than the GC horizon, because it is still
-needed by the child branch.  'main/orders_200_300' can still be
-removed. So after garbage collection, these files would remain:
-
-	main/orders_100_200
-
-	main/orders_300_400
-	main/orders_400_500
-	main/customers_100_200
-	child/customers_150_300
+In this situation, 'main/orders_100' and 'main/orders_100_200' cannot
+be removed, even though they are older than the GC horizon, because
+they are still needed by the child branch. 'main/orders_200'
+and 'main/orders_200_300' can still be removed.
 
 If 'orders' is modified later on the 'child' branch, we will create a
-snapshot file for it on the child:
+new base image and delta file for it on the child:
 
+	main/orders_100
 	main/orders_100_200
 
+	main/orders_300
 	main/orders_300_400
+	main/orders_400
 	main/orders_400_500
-	main/customers_100_200
-	child/customers_150_300
+	main/orders_500
+	main/customers_200
+	child/customers_300
 	child/orders_150_400
+	child/orders_400
 
-After this, the 'main/orders_100_200' file can be removed. It is no
-longer needed by the child branch, because there is a newer snapshot
-file there. TODO: This optimization hasn't been implemented! The GC
-algorithm will currently keep the file on the 'main' branch anyway, for
-as long as the child branch exists.
+After this, the 'main/orders_100' and 'main/orders_100_200' file could
+be removed. It is no longer needed by the child branch, because there
+is a newer layer file there. TODO: This optimization hasn't been
+implemented! The GC algorithm will currently keep the file on the
+'main' branch anyway, for as long as the child branch exists.
 
 
 # TODO: On LSN ranges
@@ -265,34 +372,48 @@ as long as the child branch exists.
 In principle, each relation can be checkpointed separately, i.e. the
 LSN ranges of the files don't need to line up. So this would be legal:
 
+	main/orders_100
 	main/orders_100_200
+	main/orders_200
 	main/orders_200_300
+	main/orders_300
 	main/orders_300_400
+	main/orders_400
+	main/customers_150
 	main/customers_150_250
+	main/customers_250
 	main/customers_250_500
+	main/customers_500
 
 However, the code currently always checkpoints all relations together.
 So that situation doesn't arise in practice.
 
 It would also be OK to have overlapping LSN ranges for the same relation:
 
+	main/orders_100
 	main/orders_100_200
+	main/orders_200
 	main/orders_200_300
+	main/orders_300
 	main/orders_250_350
+	main/orders_350
 	main/orders_300_400
+	main/orders_400
 
-The code that reads the snapshot files should cope with this, but this
+The code that reads the layer files should cope with this, but this
 situation doesn't arise either, because the checkpointing code never
 does that.  It could be useful, however, as a transient state when
 garbage collecting around branch points, or explicit recovery
 points. For example, if we start with this:
 
+	main/orders_100
 	main/orders_100_200
+	main/orders_200
 	main/orders_200_300
-	main/orders_300_400
+	main/orders_300
 
 And there is a branch or explicit recovery point at LSN 150, we could
-replace 'main/orders_100_200' with 'main/orders_150_150' to keep a
-snapshot only at that exact point that's still needed, removing the
+replace 'main/orders_100_200' with 'main/orders_150' to keep a
+layer only at that exact point that's still needed, removing the
 other page versions around it. But such compaction has not been
 implemented yet.

pageserver/src/layered_repository/blob.rs

@@ -0,0 +1,45 @@
+use std::{fs::File, io::Write};
+
+use anyhow::Result;
+use bookfile::{BookWriter, BoundedReader, ChapterId, ChapterWriter};
+use serde::{Deserialize, Serialize};
+
+#[derive(Serialize, Deserialize)]
+pub struct BlobRange {
+    offset: u64,
+    size: usize,
+}
+
+pub fn read_blob(reader: &BoundedReader<&'_ File>, range: &BlobRange) -> Result<Box<[u8]>> {
+    let mut buf = vec![0u8; range.size];
+    reader.read_exact_at(&mut buf, range.offset)?;
+    Ok(buf.into_boxed_slice())
+}
+
+pub struct BlobWriter<W> {
+    writer: ChapterWriter<W>,
+    offset: u64,
+}
+
+impl<W: Write> BlobWriter<W> {
+    // This function takes a BookWriter and creates a new chapter to ensure offset is 0.
+    pub fn new(book_writer: BookWriter<W>, chapter_id: impl Into<ChapterId>) -> Self {
+        let writer = book_writer.new_chapter(chapter_id);
+        Self { writer, offset: 0 }
+    }
+
+    pub fn write_blob(&mut self, blob: &[u8]) -> Result<BlobRange> {
+        self.writer.write_all(blob)?;
+
+        let range = BlobRange {
+            offset: self.offset,
+            size: blob.len(),
+        };
+        self.offset += blob.len() as u64;
+        Ok(range)
+    }
+
+    pub fn close(self) -> bookfile::Result<BookWriter<W>> {
+        self.writer.close()
+    }
+}

pageserver/src/layered_repository/delta_layer.rs

@@ -0,0 +1,585 @@
+//!
+//! A DeltaLayer represents a collection of WAL records or page images in a range of
+//! LSNs, for one segment. It is stored on a file on disk.
+//!
+//! Usually a delta layer only contains differences - in the form of WAL records against
+//! a base LSN. However, if a segment is newly created, by creating a new relation or
+//! extending an old one, there might be no base image. In that case, all the entries in
+//! the delta layer must be page images or WAL records with the 'will_init' flag set, so
+//! that they can be replayed without referring to an older page version. Also in some
+//! circumstances, the predecessor layer might actually be another delta layer. That
+//! can happen when you create a new branch in the middle of a delta layer, and the WAL
+//! records on the new branch are put in a new delta layer.
+//!
+//! When a delta file needs to be accessed, we slurp the metadata and relsize chapters
+//! into memory, into the DeltaLayerInner struct. See load() and unload() functions.
+//! To access a page/WAL record, we search `page_version_metas` for the block # and LSN.
+//! The byte ranges in the metadata can be used to find the page/WAL record in
+//! PAGE_VERSIONS_CHAPTER.
+//!
+//! On disk, the delta files are stored in timelines/<timelineid> directory.
+//! Currently, there are no subdirectories, and each delta file is named like this:
+//!
+//!    <spcnode>_<dbnode>_<relnode>_<forknum>_<segno>_<start LSN>_<end LSN>
+//!
+//! For example:
+//!
+//!    1663_13990_2609_0_5_000000000169C348_000000000169C349
+//!
+//! If a relation is dropped, we add a '_DROPPED' to the end of the filename to indicate that.
+//! So the above example would become:
+//!
+//!    1663_13990_2609_0_5_000000000169C348_000000000169C349_DROPPED
+//!
+//! The end LSN indicates when it was dropped in that case, we don't store it in the
+//! file contents in any way.
+//!
+//! A detlta file is constructed using the 'bookfile' crate. Each file consists of two
+//! parts: the page versions and the relation sizes. They are stored as separate chapters.
+//!
+use crate::layered_repository::blob::BlobWriter;
+use crate::layered_repository::filename::{DeltaFileName, PathOrConf};
+use crate::layered_repository::page_versions::PageVersions;
+use crate::layered_repository::storage_layer::{
+    Layer, PageReconstructData, PageReconstructResult, PageVersion, SegmentTag,
+};
+use crate::waldecoder;
+use crate::PageServerConf;
+use crate::{ZTenantId, ZTimelineId};
+use anyhow::{bail, ensure, Result};
+use bytes::Bytes;
+use log::*;
+use serde::{Deserialize, Serialize};
+use zenith_utils::vec_map::VecMap;
+// avoid binding to Write (conflicts with std::io::Write)
+// while being able to use std::fmt::Write's methods
+use std::fmt::Write as _;
+use std::fs;
+use std::fs::File;
+use std::io::{BufWriter, Write};
+use std::ops::Bound::Included;
+use std::path::{Path, PathBuf};
+use std::sync::{Mutex, MutexGuard};
+
+use bookfile::{Book, BookWriter};
+
+use zenith_utils::bin_ser::BeSer;
+use zenith_utils::lsn::Lsn;
+
+use super::blob::{read_blob, BlobRange};
+
+// Magic constant to identify a Zenith delta file
+pub const DELTA_FILE_MAGIC: u32 = 0x5A616E01;
+
+/// Mapping from (block #, lsn) -> page/WAL record
+/// byte ranges in PAGE_VERSIONS_CHAPTER
+static PAGE_VERSION_METAS_CHAPTER: u64 = 1;
+/// Page/WAL bytes - cannot be interpreted
+/// without PAGE_VERSION_METAS_CHAPTER
+static PAGE_VERSIONS_CHAPTER: u64 = 2;
+static REL_SIZES_CHAPTER: u64 = 3;
+
+/// Contains the [`Summary`] struct
+static SUMMARY_CHAPTER: u64 = 4;
+
+#[derive(Debug, Serialize, Deserialize, PartialEq, Eq)]
+struct Summary {
+    tenantid: ZTenantId,
+    timelineid: ZTimelineId,
+    seg: SegmentTag,
+
+    start_lsn: Lsn,
+    end_lsn: Lsn,
+
+    dropped: bool,
+}
+
+impl From<&DeltaLayer> for Summary {
+    fn from(layer: &DeltaLayer) -> Self {
+        Self {
+            tenantid: layer.tenantid,
+            timelineid: layer.timelineid,
+            seg: layer.seg,
+
+            start_lsn: layer.start_lsn,
+            end_lsn: layer.end_lsn,
+
+            dropped: layer.dropped,
+        }
+    }
+}
+
+///
+/// DeltaLayer is the in-memory data structure associated with an
+/// on-disk delta file.  We keep a DeltaLayer in memory for each
+/// file, in the LayerMap. If a layer is in "loaded" state, we have a
+/// copy of the file in memory, in 'inner'. Otherwise the struct is
+/// just a placeholder for a file that exists on disk, and it needs to
+/// be loaded before using it in queries.
+///
+pub struct DeltaLayer {
+    path_or_conf: PathOrConf,
+
+    pub tenantid: ZTenantId,
+    pub timelineid: ZTimelineId,
+    pub seg: SegmentTag,
+
+    //
+    // This entry contains all the changes from 'start_lsn' to 'end_lsn'. The
+    // start is inclusive, and end is exclusive.
+    //
+    pub start_lsn: Lsn,
+    pub end_lsn: Lsn,
+
+    dropped: bool,
+
+    inner: Mutex<DeltaLayerInner>,
+}
+
+pub struct DeltaLayerInner {
+    /// If false, the 'page_version_metas' and 'relsizes' have not been
+    /// loaded into memory yet.
+    loaded: bool,
+
+    /// All versions of all pages in the file are are kept here.
+    /// Indexed by block number and LSN.
+    page_version_metas: VecMap<(u32, Lsn), BlobRange>,
+
+    /// `relsizes` tracks the size of the relation at different points in time.
+    relsizes: VecMap<Lsn, u32>,
+}
+
+impl Layer for DeltaLayer {
+    fn get_tenant_id(&self) -> ZTenantId {
+        self.tenantid
+    }
+
+    fn get_timeline_id(&self) -> ZTimelineId {
+        self.timelineid
+    }
+
+    fn get_seg_tag(&self) -> SegmentTag {
+        self.seg
+    }
+
+    fn is_dropped(&self) -> bool {
+        self.dropped
+    }
+
+    fn get_start_lsn(&self) -> Lsn {
+        self.start_lsn
+    }
+
+    fn get_end_lsn(&self) -> Lsn {
+        self.end_lsn
+    }
+
+    fn filename(&self) -> PathBuf {
+        PathBuf::from(self.layer_name().to_string())
+    }
+
+    /// Look up given page in the cache.
+    fn get_page_reconstruct_data(
+        &self,
+        blknum: u32,
+        lsn: Lsn,
+        reconstruct_data: &mut PageReconstructData,
+    ) -> Result<PageReconstructResult> {
+        let mut need_image = true;
+
+        assert!(self.seg.blknum_in_seg(blknum));
+
+        {
+            // Open the file and lock the metadata in memory
+            // TODO: avoid opening the file for each read
+            let (_path, book) = self.open_book()?;
+            let page_version_reader = book.chapter_reader(PAGE_VERSIONS_CHAPTER)?;
+            let inner = self.load()?;
+
+            // Scan the metadata BTreeMap backwards, starting from the given entry.
+            let minkey = (blknum, Lsn(0));
+            let maxkey = (blknum, lsn);
+            let iter = inner
+                .page_version_metas
+                .slice_range((Included(&minkey), Included(&maxkey)))
+                .iter()
+                .rev();
+            for ((_blknum, pv_lsn), blob_range) in iter {
+                let pv_bytes = read_blob(&page_version_reader, blob_range)?;
+                let pv = PageVersion::from_bytes(pv_bytes);
+
+                match pv {
+                    PageVersion::Page(img) => {
+                        // Found a page image, return it
+                        reconstruct_data.page_img = Some(img);
+                        need_image = false;
+                        break;
+                    }
+                    PageVersion::Wal(rec) => {
+                        let will_init = rec.will_init();
+                        reconstruct_data.records.push((*pv_lsn, rec));
+                        if will_init {
+                            // This WAL record initializes the page, so no need to go further back
+                            need_image = false;
+                            break;
+                        }
+                    }
+                }
+            }
+
+            // release metadata lock and close the file
+        }
+
+        // If an older page image is needed to reconstruct the page, let the
+        // caller know.
+        if need_image {
+            Ok(PageReconstructResult::Continue(Lsn(self.start_lsn.0 - 1)))
+        } else {
+            Ok(PageReconstructResult::Complete)
+        }
+    }
+
+    /// Get size of the relation at given LSN
+    fn get_seg_size(&self, lsn: Lsn) -> Result<u32> {
+        assert!(lsn >= self.start_lsn);
+        ensure!(
+            self.seg.rel.is_blocky(),
+            "get_seg_size() called on a non-blocky rel"
+        );
+
+        // Scan the BTreeMap backwards, starting from the given entry.
+        let inner = self.load()?;
+        let slice = inner
+            .relsizes
+            .slice_range((Included(&Lsn(0)), Included(&lsn)));
+
+        if let Some((_entry_lsn, entry)) = slice.last() {
+            Ok(*entry)
+        } else {
+            Err(anyhow::anyhow!("could not find seg size in delta layer"))
+        }
+    }
+
+    /// Does this segment exist at given LSN?
+    fn get_seg_exists(&self, lsn: Lsn) -> Result<bool> {
+        // Is the requested LSN after the rel was dropped?
+        if self.dropped && lsn >= self.end_lsn {
+            return Ok(false);
+        }
+
+        // Otherwise, it exists.
+        Ok(true)
+    }
+
+    ///
+    /// Release most of the memory used by this layer. If it's accessed again later,
+    /// it will need to be loaded back.
+    ///
+    fn unload(&self) -> Result<()> {
+        let mut inner = self.inner.lock().unwrap();
+        inner.page_version_metas = VecMap::default();
+        inner.relsizes = VecMap::default();
+        inner.loaded = false;
+        Ok(())
+    }
+
+    fn delete(&self) -> Result<()> {
+        // delete underlying file
+        fs::remove_file(self.path())?;
+        Ok(())
+    }
+
+    fn is_incremental(&self) -> bool {
+        true
+    }
+
+    /// debugging function to print out the contents of the layer
+    fn dump(&self) -> Result<()> {
+        println!(
+            "----- delta layer for ten {} tli {} seg {} {}-{} ----",
+            self.tenantid, self.timelineid, self.seg, self.start_lsn, self.end_lsn
+        );
+
+        println!("--- relsizes ---");
+        let inner = self.load()?;
+        for (k, v) in inner.relsizes.as_slice() {
+            println!("  {}: {}", k, v);
+        }
+        println!("--- page versions ---");
+        let (_path, book) = self.open_book()?;
+        let chapter = book.chapter_reader(PAGE_VERSIONS_CHAPTER)?;
+        for ((blk, lsn), blob_range) in inner.page_version_metas.as_slice() {
+            let mut desc = String::new();
+
+            let buf = read_blob(&chapter, blob_range)?;
+            let pv = PageVersion::from_bytes(buf);
+
+            match pv {
+                PageVersion::Page(page) => {
+                    write!(&mut desc, " img {} bytes", page.image().len())?;
+                }
+                PageVersion::Wal(rec) => {
+                    let wal_desc =
+                        waldecoder::describe_wal_record(&Bytes::from(rec.rec().to_vec()));
+                    write!(
+                        &mut desc,
+                        " rec {} bytes will_init: {} {}",
+                        rec.rec().len(),
+                        rec.will_init(),
+                        wal_desc
+                    )?;
+                }
+            }
+
+            println!("  blk {} at {}: {}", blk, lsn, desc);
+        }
+
+        Ok(())
+    }
+}
+
+impl DeltaLayer {
+    fn path_for(
+        path_or_conf: &PathOrConf,
+        timelineid: ZTimelineId,
+        tenantid: ZTenantId,
+        fname: &DeltaFileName,
+    ) -> PathBuf {
+        match path_or_conf {
+            PathOrConf::Path(path) => path.clone(),
+            PathOrConf::Conf(conf) => conf
+                .timeline_path(&timelineid, &tenantid)
+                .join(fname.to_string()),
+        }
+    }
+
+    /// Create a new delta file, using the given page versions and relsizes.
+    /// The page versions are passed in a PageVersions struct. If 'cutoff' is
+    /// given, only page versions with LSN < cutoff are included.
+    ///
+    /// This is used to write the in-memory layer to disk. The page_versions and
+    /// relsizes are thus passed in the same format as they are in the in-memory
+    /// layer, as that's expedient.
+    #[allow(clippy::too_many_arguments)]
+    pub fn create(
+        conf: &'static PageServerConf,
+        timelineid: ZTimelineId,
+        tenantid: ZTenantId,
+        seg: SegmentTag,
+        start_lsn: Lsn,
+        end_lsn: Lsn,
+        dropped: bool,
+        page_versions: &PageVersions,
+        cutoff: Option<Lsn>,
+        relsizes: VecMap<Lsn, u32>,
+    ) -> Result<DeltaLayer> {
+        if seg.rel.is_blocky() {
+            assert!(!relsizes.is_empty());
+        }
+
+        let delta_layer = DeltaLayer {
+            path_or_conf: PathOrConf::Conf(conf),
+            timelineid,
+            tenantid,
+            seg,
+            start_lsn,
+            end_lsn,
+            dropped,
+            inner: Mutex::new(DeltaLayerInner {
+                loaded: true,
+                page_version_metas: VecMap::default(),
+                relsizes,
+            }),
+        };
+        let mut inner = delta_layer.inner.lock().unwrap();
+
+        // Write the in-memory btreemaps into a file
+        let path = delta_layer.path();
+
+        // Note: This overwrites any existing file. There shouldn't be any.
+        // FIXME: throw an error instead?
+        let file = File::create(&path)?;
+        let buf_writer = BufWriter::new(file);
+        let book = BookWriter::new(buf_writer, DELTA_FILE_MAGIC)?;
+
+        let mut page_version_writer = BlobWriter::new(book, PAGE_VERSIONS_CHAPTER);
+
+        let page_versions_iter = page_versions.ordered_page_version_iter(cutoff);
+        for (blknum, lsn, token) in page_versions_iter {
+            let blob_range = page_version_writer
+                .write_blob(page_versions.get_page_version_bytes(token).as_slice())?;
+
+            inner
+                .page_version_metas
+                .append((blknum, lsn), blob_range)
+                .unwrap();
+        }
+
+        let book = page_version_writer.close()?;
+
+        // Write out page versions
+        let mut chapter = book.new_chapter(PAGE_VERSION_METAS_CHAPTER);
+        let buf = VecMap::ser(&inner.page_version_metas)?;
+        chapter.write_all(&buf)?;
+        let book = chapter.close()?;
+
+        // and relsizes to separate chapter
+        let mut chapter = book.new_chapter(REL_SIZES_CHAPTER);
+        let buf = VecMap::ser(&inner.relsizes)?;
+        chapter.write_all(&buf)?;
+        let book = chapter.close()?;
+
+        let mut chapter = book.new_chapter(SUMMARY_CHAPTER);
+        let summary = Summary {
+            tenantid,
+            timelineid,
+            seg,
+
+            start_lsn,
+            end_lsn,
+
+            dropped,
+        };
+        Summary::ser_into(&summary, &mut chapter)?;
+        let book = chapter.close()?;
+
+        // This flushes the underlying 'buf_writer'.
+        let writer = book.close()?;
+        writer.get_ref().sync_all()?;
+
+        trace!("saved {}", &path.display());
+
+        drop(inner);
+
+        Ok(delta_layer)
+    }
+
+    fn open_book(&self) -> Result<(PathBuf, Book<File>)> {
+        let path = self.path();
+
+        let file = File::open(&path)?;
+        let book = Book::new(file)?;
+
+        Ok((path, book))
+    }
+
+    ///
+    /// Load the contents of the file into memory
+    ///
+    fn load(&self) -> Result<MutexGuard<DeltaLayerInner>> {
+        // quick exit if already loaded
+        let mut inner = self.inner.lock().unwrap();
+
+        if inner.loaded {
+            return Ok(inner);
+        }
+
+        let (path, book) = self.open_book()?;
+
+        match &self.path_or_conf {
+            PathOrConf::Conf(_) => {
+                let chapter = book.read_chapter(SUMMARY_CHAPTER)?;
+                let actual_summary = Summary::des(&chapter)?;
+
+                let expected_summary = Summary::from(self);
+
+                if actual_summary != expected_summary {
+                    bail!("in-file summary does not match expected summary. actual = {:?} expected = {:?}", actual_summary, expected_summary);
+                }
+            }
+            PathOrConf::Path(path) => {
+                let actual_filename = Path::new(path.file_name().unwrap());
+                let expected_filename = self.filename();
+
+                if actual_filename != expected_filename {
+                    println!(
+                        "warning: filename does not match what is expected from in-file summary"
+                    );
+                    println!("actual: {:?}", actual_filename);
+                    println!("expected: {:?}", expected_filename);
+                }
+            }
+        }
+
+        let chapter = book.read_chapter(PAGE_VERSION_METAS_CHAPTER)?;
+        let page_version_metas = VecMap::des(&chapter)?;
+
+        let chapter = book.read_chapter(REL_SIZES_CHAPTER)?;
+        let relsizes = VecMap::des(&chapter)?;
+
+        debug!("loaded from {}", &path.display());
+
+        *inner = DeltaLayerInner {
+            loaded: true,
+            page_version_metas,
+            relsizes,
+        };
+
+        Ok(inner)
+    }
+
+    /// Create a DeltaLayer struct representing an existing file on disk.
+    pub fn new(
+        conf: &'static PageServerConf,
+        timelineid: ZTimelineId,
+        tenantid: ZTenantId,
+        filename: &DeltaFileName,
+    ) -> DeltaLayer {
+        DeltaLayer {
+            path_or_conf: PathOrConf::Conf(conf),
+            timelineid,
+            tenantid,
+            seg: filename.seg,
+            start_lsn: filename.start_lsn,
+            end_lsn: filename.end_lsn,
+            dropped: filename.dropped,
+            inner: Mutex::new(DeltaLayerInner {
+                loaded: false,
+                page_version_metas: VecMap::default(),
+                relsizes: VecMap::default(),
+            }),
+        }
+    }
+
+    /// Create a DeltaLayer struct representing an existing file on disk.
+    ///
+    /// This variant is only used for debugging purposes, by the 'dump_layerfile' binary.
+    pub fn new_for_path(path: &Path, book: &Book<File>) -> Result<Self> {
+        let chapter = book.read_chapter(SUMMARY_CHAPTER)?;
+        let summary = Summary::des(&chapter)?;
+
+        Ok(DeltaLayer {
+            path_or_conf: PathOrConf::Path(path.to_path_buf()),
+            timelineid: summary.timelineid,
+            tenantid: summary.tenantid,
+            seg: summary.seg,
+            start_lsn: summary.start_lsn,
+            end_lsn: summary.end_lsn,
+            dropped: summary.dropped,
+            inner: Mutex::new(DeltaLayerInner {
+                loaded: false,
+                page_version_metas: VecMap::default(),
+                relsizes: VecMap::default(),
+            }),
+        })
+    }
+
+    fn layer_name(&self) -> DeltaFileName {
+        DeltaFileName {
+            seg: self.seg,
+            start_lsn: self.start_lsn,
+            end_lsn: self.end_lsn,
+            dropped: self.dropped,
+        }
+    }
+
+    /// Path to the layer file in pageserver workdir.
+    pub fn path(&self) -> PathBuf {
+        Self::path_for(
+            &self.path_or_conf,
+            self.timelineid,
+            self.tenantid,
+            &self.layer_name(),
+        )
+    }
+}

pageserver/src/layered_repository/filename.rs

@@ -0,0 +1,315 @@
+//!
+//! Helper functions for dealing with filenames of the image and delta layer files.
+//!
+use crate::layered_repository::storage_layer::SegmentTag;
+use crate::relish::*;
+use crate::PageServerConf;
+use crate::{ZTenantId, ZTimelineId};
+use std::fmt;
+use std::fs;
+use std::path::PathBuf;
+
+use anyhow::Result;
+use log::*;
+use zenith_utils::lsn::Lsn;
+
+use super::metadata::METADATA_FILE_NAME;
+
+// Note: LayeredTimeline::load_layer_map() relies on this sort order
+#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Clone)]
+pub struct DeltaFileName {
+    pub seg: SegmentTag,
+    pub start_lsn: Lsn,
+    pub end_lsn: Lsn,
+    pub dropped: bool,
+}
+
+/// Represents the filename of a DeltaLayer
+///
+///    <spcnode>_<dbnode>_<relnode>_<forknum>_<seg>_<start LSN>_<end LSN>
+///
+/// or if it was dropped:
+///
+///    <spcnode>_<dbnode>_<relnode>_<forknum>_<seg>_<start LSN>_<end LSN>_DROPPED
+///
+impl DeltaFileName {
+    ///
+    /// Parse a string as a delta file name. Returns None if the filename does not
+    /// match the expected pattern.
+    ///
+    pub fn parse_str(fname: &str) -> Option<Self> {
+        let rel;
+        let mut parts;
+        if let Some(rest) = fname.strip_prefix("rel_") {
+            parts = rest.split('_');
+            rel = RelishTag::Relation(RelTag {
+                spcnode: parts.next()?.parse::<u32>().ok()?,
+                dbnode: parts.next()?.parse::<u32>().ok()?,
+                relnode: parts.next()?.parse::<u32>().ok()?,
+                forknum: parts.next()?.parse::<u8>().ok()?,
+            });
+        } else if let Some(rest) = fname.strip_prefix("pg_xact_") {
+            parts = rest.split('_');
+            rel = RelishTag::Slru {
+                slru: SlruKind::Clog,
+                segno: u32::from_str_radix(parts.next()?, 16).ok()?,
+            };
+        } else if let Some(rest) = fname.strip_prefix("pg_multixact_members_") {
+            parts = rest.split('_');
+            rel = RelishTag::Slru {
+                slru: SlruKind::MultiXactMembers,
+                segno: u32::from_str_radix(parts.next()?, 16).ok()?,
+            };
+        } else if let Some(rest) = fname.strip_prefix("pg_multixact_offsets_") {
+            parts = rest.split('_');
+            rel = RelishTag::Slru {
+                slru: SlruKind::MultiXactOffsets,
+                segno: u32::from_str_radix(parts.next()?, 16).ok()?,
+            };
+        } else if let Some(rest) = fname.strip_prefix("pg_filenodemap_") {
+            parts = rest.split('_');
+            rel = RelishTag::FileNodeMap {
+                spcnode: parts.next()?.parse::<u32>().ok()?,
+                dbnode: parts.next()?.parse::<u32>().ok()?,
+            };
+        } else if let Some(rest) = fname.strip_prefix("pg_twophase_") {
+            parts = rest.split('_');
+            rel = RelishTag::TwoPhase {
+                xid: parts.next()?.parse::<u32>().ok()?,
+            };
+        } else if let Some(rest) = fname.strip_prefix("pg_control_checkpoint_") {
+            parts = rest.split('_');
+            rel = RelishTag::Checkpoint;
+        } else if let Some(rest) = fname.strip_prefix("pg_control_") {
+            parts = rest.split('_');
+            rel = RelishTag::ControlFile;
+        } else {
+            return None;
+        }
+
+        let segno = parts.next()?.parse::<u32>().ok()?;
+
+        let seg = SegmentTag { rel, segno };
+
+        let start_lsn = Lsn::from_hex(parts.next()?).ok()?;
+        let end_lsn = Lsn::from_hex(parts.next()?).ok()?;
+
+        let mut dropped = false;
+        if let Some(suffix) = parts.next() {
+            if suffix == "DROPPED" {
+                dropped = true;
+            } else {
+                return None;
+            }
+        }
+        if parts.next().is_some() {
+            return None;
+        }
+
+        Some(DeltaFileName {
+            seg,
+            start_lsn,
+            end_lsn,
+            dropped,
+        })
+    }
+}
+
+impl fmt::Display for DeltaFileName {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let basename = match self.seg.rel {
+            RelishTag::Relation(reltag) => format!(
+                "rel_{}_{}_{}_{}",
+                reltag.spcnode, reltag.dbnode, reltag.relnode, reltag.forknum
+            ),
+            RelishTag::Slru {
+                slru: SlruKind::Clog,
+                segno,
+            } => format!("pg_xact_{:04X}", segno),
+            RelishTag::Slru {
+                slru: SlruKind::MultiXactMembers,
+                segno,
+            } => format!("pg_multixact_members_{:04X}", segno),
+            RelishTag::Slru {
+                slru: SlruKind::MultiXactOffsets,
+                segno,
+            } => format!("pg_multixact_offsets_{:04X}", segno),
+            RelishTag::FileNodeMap { spcnode, dbnode } => {
+                format!("pg_filenodemap_{}_{}", spcnode, dbnode)
+            }
+            RelishTag::TwoPhase { xid } => format!("pg_twophase_{}", xid),
+            RelishTag::Checkpoint => "pg_control_checkpoint".to_string(),
+            RelishTag::ControlFile => "pg_control".to_string(),
+        };
+
+        write!(
+            f,
+            "{}_{}_{:016X}_{:016X}{}",
+            basename,
+            self.seg.segno,
+            u64::from(self.start_lsn),
+            u64::from(self.end_lsn),
+            if self.dropped { "_DROPPED" } else { "" }
+        )
+    }
+}
+
+#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Clone)]
+pub struct ImageFileName {
+    pub seg: SegmentTag,
+    pub lsn: Lsn,
+}
+
+///
+/// Represents the filename of an ImageLayer
+///
+///    <spcnode>_<dbnode>_<relnode>_<forknum>_<seg>_<LSN>
+///
+impl ImageFileName {
+    ///
+    /// Parse a string as an image file name. Returns None if the filename does not
+    /// match the expected pattern.
+    ///
+    pub fn parse_str(fname: &str) -> Option<Self> {
+        let rel;
+        let mut parts;
+        if let Some(rest) = fname.strip_prefix("rel_") {
+            parts = rest.split('_');
+            rel = RelishTag::Relation(RelTag {
+                spcnode: parts.next()?.parse::<u32>().ok()?,
+                dbnode: parts.next()?.parse::<u32>().ok()?,
+                relnode: parts.next()?.parse::<u32>().ok()?,
+                forknum: parts.next()?.parse::<u8>().ok()?,
+            });
+        } else if let Some(rest) = fname.strip_prefix("pg_xact_") {
+            parts = rest.split('_');
+            rel = RelishTag::Slru {
+                slru: SlruKind::Clog,
+                segno: u32::from_str_radix(parts.next()?, 16).ok()?,
+            };
+        } else if let Some(rest) = fname.strip_prefix("pg_multixact_members_") {
+            parts = rest.split('_');
+            rel = RelishTag::Slru {
+                slru: SlruKind::MultiXactMembers,
+                segno: u32::from_str_radix(parts.next()?, 16).ok()?,
+            };
+        } else if let Some(rest) = fname.strip_prefix("pg_multixact_offsets_") {
+            parts = rest.split('_');
+            rel = RelishTag::Slru {
+                slru: SlruKind::MultiXactOffsets,
+                segno: u32::from_str_radix(parts.next()?, 16).ok()?,
+            };
+        } else if let Some(rest) = fname.strip_prefix("pg_filenodemap_") {
+            parts = rest.split('_');
+            rel = RelishTag::FileNodeMap {
+                spcnode: parts.next()?.parse::<u32>().ok()?,
+                dbnode: parts.next()?.parse::<u32>().ok()?,
+            };
+        } else if let Some(rest) = fname.strip_prefix("pg_twophase_") {
+            parts = rest.split('_');
+            rel = RelishTag::TwoPhase {
+                xid: parts.next()?.parse::<u32>().ok()?,
+            };
+        } else if let Some(rest) = fname.strip_prefix("pg_control_checkpoint_") {
+            parts = rest.split('_');
+            rel = RelishTag::Checkpoint;
+        } else if let Some(rest) = fname.strip_prefix("pg_control_") {
+            parts = rest.split('_');
+            rel = RelishTag::ControlFile;
+        } else {
+            return None;
+        }
+
+        let segno = parts.next()?.parse::<u32>().ok()?;
+
+        let seg = SegmentTag { rel, segno };
+
+        let lsn = Lsn::from_hex(parts.next()?).ok()?;
+
+        if parts.next().is_some() {
+            return None;
+        }
+
+        Some(ImageFileName { seg, lsn })
+    }
+}
+
+impl fmt::Display for ImageFileName {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let basename = match self.seg.rel {
+            RelishTag::Relation(reltag) => format!(
+                "rel_{}_{}_{}_{}",
+                reltag.spcnode, reltag.dbnode, reltag.relnode, reltag.forknum
+            ),
+            RelishTag::Slru {
+                slru: SlruKind::Clog,
+                segno,
+            } => format!("pg_xact_{:04X}", segno),
+            RelishTag::Slru {
+                slru: SlruKind::MultiXactMembers,
+                segno,
+            } => format!("pg_multixact_members_{:04X}", segno),
+            RelishTag::Slru {
+                slru: SlruKind::MultiXactOffsets,
+                segno,
+            } => format!("pg_multixact_offsets_{:04X}", segno),
+            RelishTag::FileNodeMap { spcnode, dbnode } => {
+                format!("pg_filenodemap_{}_{}", spcnode, dbnode)
+            }
+            RelishTag::TwoPhase { xid } => format!("pg_twophase_{}", xid),
+            RelishTag::Checkpoint => "pg_control_checkpoint".to_string(),
+            RelishTag::ControlFile => "pg_control".to_string(),
+        };
+
+        write!(
+            f,
+            "{}_{}_{:016X}",
+            basename,
+            self.seg.segno,
+            u64::from(self.lsn),
+        )
+    }
+}
+
+/// Scan timeline directory and create ImageFileName and DeltaFilename
+/// structs representing all files on disk
+///
+/// TODO: returning an Iterator would be more idiomatic
+pub fn list_files(
+    conf: &'static PageServerConf,
+    timelineid: ZTimelineId,
+    tenantid: ZTenantId,
+) -> Result<(Vec<ImageFileName>, Vec<DeltaFileName>)> {
+    let path = conf.timeline_path(&timelineid, &tenantid);
+
+    let mut deltafiles: Vec<DeltaFileName> = Vec::new();
+    let mut imgfiles: Vec<ImageFileName> = Vec::new();
+    for direntry in fs::read_dir(path)? {
+        let fname = direntry?.file_name();
+        let fname = fname.to_str().unwrap();
+
+        if let Some(deltafilename) = DeltaFileName::parse_str(fname) {
+            deltafiles.push(deltafilename);
+        } else if let Some(imgfilename) = ImageFileName::parse_str(fname) {
+            imgfiles.push(imgfilename);
+        } else if fname == METADATA_FILE_NAME || fname == "ancestor" || fname.ends_with(".old") {
+            // ignore these
+        } else {
+            warn!("unrecognized filename in timeline dir: {}", fname);
+        }
+    }
+    Ok((imgfiles, deltafiles))
+}
+
+/// Helper enum to hold a PageServerConf, or a path
+///
+/// This is used by DeltaLayer and ImageLayer. Normally, this holds a reference to the
+/// global config, and paths to layer files are constructed using the tenant/timeline
+/// path from the config. But in the 'dump_layerfile' binary, we need to construct a Layer
+/// struct for a file on disk, without having a page server running, so that we have no
+/// config. In that case, we use the Path variant to hold the full path to the file on
+/// disk.
+pub enum PathOrConf {
+    Path(PathBuf),
+    Conf(&'static PageServerConf),
+}

pageserver/src/layered_repository/global_layer_map.rs

@@ -0,0 +1,209 @@
+//!
+//! Global registry of open layers.
+//!
+//! Whenever a new in-memory layer is created to hold incoming WAL, it is registered
+//! in [`GLOBAL_LAYER_MAP`], so that we can keep track of the total number of
+//! in-memory layers in the system, and know when we need to evict some to release
+//! memory.
+//!
+//! Each layer is assigned a unique ID when it's registered in the global registry.
+//! The ID can be used to relocate the layer later, without having to hold locks.
+//!
+
+use std::sync::atomic::{AtomicU8, AtomicUsize, Ordering};
+use std::sync::{Arc, RwLock};
+
+use super::inmemory_layer::InMemoryLayer;
+
+use lazy_static::lazy_static;
+
+const MAX_USAGE_COUNT: u8 = 5;
+
+lazy_static! {
+    pub static ref GLOBAL_LAYER_MAP: RwLock<OpenLayers> = RwLock::new(OpenLayers::default());
+}
+
+///
+/// How much memory is being used by all the open layers? This is used to trigger
+/// freezing and evicting an open layer to disk.
+///
+/// This is only a rough approximation, it leaves out a lot of things like malloc()
+/// overhead. But as long there is enough "slop" and it's not set too close to the RAM
+/// size on the system, it's good enough.
+pub static GLOBAL_OPEN_MEM_USAGE: AtomicUsize = AtomicUsize::new(0);
+
+// TODO these types can probably be smaller
+#[derive(PartialEq, Eq, Clone, Copy)]
+pub struct LayerId {
+    index: usize,
+    tag: u64, // to avoid ABA problem
+}
+
+enum SlotData {
+    Occupied(Arc<InMemoryLayer>),
+    /// Vacant slots form a linked list, the value is the index
+    /// of the next vacant slot in the list.
+    Vacant(Option<usize>),
+}
+
+struct Slot {
+    tag: u64,
+    data: SlotData,
+    usage_count: AtomicU8, // for clock algorithm
+}
+
+#[derive(Default)]
+pub struct OpenLayers {
+    slots: Vec<Slot>,
+    num_occupied: usize,
+    next_victim: AtomicUsize,
+
+    // Head of free-slot list.
+    next_empty_slot_idx: Option<usize>,
+}
+
+impl OpenLayers {
+    pub fn insert(&mut self, layer: Arc<InMemoryLayer>) -> LayerId {
+        let slot_idx = match self.next_empty_slot_idx {
+            Some(slot_idx) => slot_idx,
+            None => {
+                let idx = self.slots.len();
+                self.slots.push(Slot {
+                    tag: 0,
+                    data: SlotData::Vacant(None),
+                    usage_count: AtomicU8::new(0),
+                });
+                idx
+            }
+        };
+        let slots_len = self.slots.len();
+
+        let slot = &mut self.slots[slot_idx];
+
+        match slot.data {
+            SlotData::Occupied(_) => {
+                panic!("an occupied slot was in the free list");
+            }
+            SlotData::Vacant(next_empty_slot_idx) => {
+                self.next_empty_slot_idx = next_empty_slot_idx;
+            }
+        }
+
+        slot.data = SlotData::Occupied(layer);
+        slot.usage_count.store(1, Ordering::Relaxed);
+
+        self.num_occupied += 1;
+        assert!(self.num_occupied <= slots_len);
+
+        LayerId {
+            index: slot_idx,
+            tag: slot.tag,
+        }
+    }
+
+    pub fn get(&self, layer_id: &LayerId) -> Option<Arc<InMemoryLayer>> {
+        let slot = self.slots.get(layer_id.index)?; // TODO should out of bounds indexes just panic?
+        if slot.tag != layer_id.tag {
+            return None;
+        }
+
+        if let SlotData::Occupied(layer) = &slot.data {
+            let _ = slot.usage_count.fetch_update(
+                Ordering::Relaxed,
+                Ordering::Relaxed,
+                |old_usage_count| {
+                    if old_usage_count < MAX_USAGE_COUNT {
+                        Some(old_usage_count + 1)
+                    } else {
+                        None
+                    }
+                },
+            );
+            Some(Arc::clone(layer))
+        } else {
+            None
+        }
+    }
+
+    /// Find a victim layer to evict, if the total memory usage of all open layers
+    /// is larger than 'limit'
+    pub fn find_victim_if_needed(&self, limit: usize) -> Option<(LayerId, Arc<InMemoryLayer>)> {
+        let mem_usage = GLOBAL_OPEN_MEM_USAGE.load(Ordering::Relaxed);
+
+        if mem_usage > limit {
+            self.find_victim()
+        } else {
+            None
+        }
+    }
+
+    pub fn find_victim(&self) -> Option<(LayerId, Arc<InMemoryLayer>)> {
+        if self.num_occupied == 0 {
+            return None;
+        }
+
+        // Run the clock algorithm.
+        //
+        // FIXME: It's theoretically possible that a constant stream of get() requests
+        // comes in faster than we advance the clock hand, so that this never finishes.
+        loop {
+            // FIXME: Because we interpret the clock hand variable modulo slots.len(), the
+            // hand effectively jumps to a more or less random place whenever the array is
+            // expanded. That's relatively harmless, it just leads to a non-optimal choice
+            // of victim. Also, in a server that runs for long enough, the array should reach
+            // a steady-state size and not grow anymore.
+            let next_victim = self.next_victim.fetch_add(1, Ordering::Relaxed) % self.slots.len();
+
+            let slot = &self.slots[next_victim];
+
+            if let SlotData::Occupied(data) = &slot.data {
+                fn update_fn(old_usage_count: u8) -> Option<u8> {
+                    if old_usage_count > 0 {
+                        Some(old_usage_count - 1)
+                    } else {
+                        None
+                    }
+                }
+
+                if slot
+                    .usage_count
+                    .fetch_update(Ordering::Relaxed, Ordering::Relaxed, update_fn)
+                    .is_err()
+                {
+                    // Found a slot with usage_count == 0. Return it.
+                    return Some((
+                        LayerId {
+                            index: next_victim,
+                            tag: slot.tag,
+                        },
+                        Arc::clone(data),
+                    ));
+                }
+            }
+        }
+    }
+
+    // TODO this won't be a public API in the future
+    pub fn remove(&mut self, layer_id: &LayerId) {
+        let slot = &mut self.slots[layer_id.index];
+
+        if slot.tag != layer_id.tag {
+            return;
+        }
+
+        match &slot.data {
+            SlotData::Occupied(_layer) => {
+                // TODO evict the layer
+            }
+            SlotData::Vacant(_) => unimplemented!(),
+        }
+
+        slot.data = SlotData::Vacant(self.next_empty_slot_idx);
+        self.next_empty_slot_idx = Some(layer_id.index);
+
+        assert!(self.num_occupied > 0);
+        self.num_occupied -= 1;
+
+        slot.tag = slot.tag.wrapping_add(1);
+    }
+}

pageserver/src/layered_repository/image_layer.rs

@@ -0,0 +1,494 @@
+//! An ImageLayer represents an image or a snapshot of a segment at one particular LSN.
+//! It is stored in a file on disk.
+//!
+//! On disk, the image files are stored in timelines/<timelineid> directory.
+//! Currently, there are no subdirectories, and each image layer file is named like this:
+//!
+//! Note that segno is
+//!    <spcnode>_<dbnode>_<relnode>_<forknum>_<segno>_<LSN>
+//!
+//! For example:
+//!
+//!    1663_13990_2609_0_5_000000000169C348
+//!
+//! An image file is constructed using the 'bookfile' crate.
+//!
+//! Only metadata is loaded into memory by the load function.
+//! When images are needed, they are read directly from disk.
+//!
+//! For blocky relishes, the images are stored in BLOCKY_IMAGES_CHAPTER.
+//! All the images are required to be BLOCK_SIZE, which allows for random access.
+//!
+//! For non-blocky relishes, the image can be found in NONBLOCKY_IMAGE_CHAPTER.
+//!
+use crate::layered_repository::filename::{ImageFileName, PathOrConf};
+use crate::layered_repository::storage_layer::{
+    Layer, Page, PageReconstructData, PageReconstructResult, SegmentTag,
+};
+use crate::layered_repository::LayeredTimeline;
+use crate::layered_repository::RELISH_SEG_SIZE;
+use crate::PageServerConf;
+use crate::{ZTenantId, ZTimelineId};
+use anyhow::{anyhow, bail, ensure, Result};
+use bytes::Bytes;
+use log::*;
+use serde::{Deserialize, Serialize};
+use std::convert::TryInto;
+use std::fs;
+use std::fs::File;
+use std::io::{BufWriter, Write};
+use std::path::{Path, PathBuf};
+use std::sync::{Mutex, MutexGuard};
+
+use bookfile::{Book, BookWriter};
+
+use zenith_utils::bin_ser::BeSer;
+use zenith_utils::lsn::Lsn;
+
+// Magic constant to identify a Zenith segment image file
+pub const IMAGE_FILE_MAGIC: u32 = 0x5A616E01 + 1;
+
+/// Contains each block in block # order
+const BLOCKY_IMAGES_CHAPTER: u64 = 1;
+const NONBLOCKY_IMAGE_CHAPTER: u64 = 2;
+
+/// Contains the [`Summary`] struct
+const SUMMARY_CHAPTER: u64 = 3;
+
+#[derive(Debug, Serialize, Deserialize, PartialEq, Eq)]
+struct Summary {
+    tenantid: ZTenantId,
+    timelineid: ZTimelineId,
+    seg: SegmentTag,
+
+    lsn: Lsn,
+}
+
+impl From<&ImageLayer> for Summary {
+    fn from(layer: &ImageLayer) -> Self {
+        Self {
+            tenantid: layer.tenantid,
+            timelineid: layer.timelineid,
+            seg: layer.seg,
+
+            lsn: layer.lsn,
+        }
+    }
+}
+
+const BLOCK_SIZE: usize = 8192;
+
+///
+/// ImageLayer is the in-memory data structure associated with an on-disk image
+/// file.  We keep an ImageLayer in memory for each file, in the LayerMap. If a
+/// layer is in "loaded" state, we have a copy of the file in memory, in 'inner'.
+/// Otherwise the struct is just a placeholder for a file that exists on disk,
+/// and it needs to be loaded before using it in queries.
+///
+pub struct ImageLayer {
+    path_or_conf: PathOrConf,
+    pub tenantid: ZTenantId,
+    pub timelineid: ZTimelineId,
+    pub seg: SegmentTag,
+
+    // This entry contains an image of all pages as of this LSN
+    pub lsn: Lsn,
+
+    inner: Mutex<ImageLayerInner>,
+}
+
+#[derive(Clone)]
+enum ImageType {
+    Blocky { num_blocks: u32 },
+    NonBlocky,
+}
+
+pub struct ImageLayerInner {
+    /// If false, the 'image_type' has not been
+    /// loaded into memory yet.
+    loaded: bool,
+
+    /// Derived from filename and bookfile chapter metadata
+    image_type: ImageType,
+}
+
+impl Layer for ImageLayer {
+    fn filename(&self) -> PathBuf {
+        PathBuf::from(self.layer_name().to_string())
+    }
+
+    fn get_tenant_id(&self) -> ZTenantId {
+        self.tenantid
+    }
+
+    fn get_timeline_id(&self) -> ZTimelineId {
+        self.timelineid
+    }
+
+    fn get_seg_tag(&self) -> SegmentTag {
+        self.seg
+    }
+
+    fn is_dropped(&self) -> bool {
+        false
+    }
+
+    fn get_start_lsn(&self) -> Lsn {
+        self.lsn
+    }
+
+    fn get_end_lsn(&self) -> Lsn {
+        // End-bound is exclusive
+        self.lsn + 1
+    }
+
+    /// Look up given page in the file
+    fn get_page_reconstruct_data(
+        &self,
+        blknum: u32,
+        lsn: Lsn,
+        reconstruct_data: &mut PageReconstructData,
+    ) -> Result<PageReconstructResult> {
+        assert!(lsn >= self.lsn);
+
+        let inner = self.load()?;
+
+        let base_blknum = blknum % RELISH_SEG_SIZE;
+
+        let (_path, book) = self.open_book()?;
+
+        let buf = match &inner.image_type {
+            ImageType::Blocky { num_blocks } => {
+                if base_blknum >= *num_blocks {
+                    return Ok(PageReconstructResult::Missing(lsn));
+                }
+
+                let mut buf = vec![0u8; BLOCK_SIZE];
+                let offset = BLOCK_SIZE as u64 * base_blknum as u64;
+
+                let chapter = book.chapter_reader(BLOCKY_IMAGES_CHAPTER)?;
+                chapter.read_exact_at(&mut buf, offset)?;
+
+                buf
+            }
+            ImageType::NonBlocky => {
+                ensure!(base_blknum == 0);
+                book.read_chapter(NONBLOCKY_IMAGE_CHAPTER)?.into_vec()
+            }
+        };
+
+        reconstruct_data.page_img = Some(Page::from_bytes(&buf));
+        Ok(PageReconstructResult::Complete)
+    }
+
+    /// Get size of the segment
+    fn get_seg_size(&self, _lsn: Lsn) -> Result<u32> {
+        let inner = self.load()?;
+        match inner.image_type {
+            ImageType::Blocky { num_blocks } => Ok(num_blocks),
+            ImageType::NonBlocky => Err(anyhow!("get_seg_size called for non-blocky segment")),
+        }
+    }
+
+    /// Does this segment exist at given LSN?
+    fn get_seg_exists(&self, _lsn: Lsn) -> Result<bool> {
+        Ok(true)
+    }
+
+    ///
+    /// Release most of the memory used by this layer. If it's accessed again later,
+    /// it will need to be loaded back.
+    ///
+    fn unload(&self) -> Result<()> {
+        let mut inner = self.inner.lock().unwrap();
+        inner.image_type = ImageType::Blocky { num_blocks: 0 };
+        inner.loaded = false;
+        Ok(())
+    }
+
+    fn delete(&self) -> Result<()> {
+        // delete underlying file
+        fs::remove_file(self.path())?;
+        Ok(())
+    }
+
+    fn is_incremental(&self) -> bool {
+        false
+    }
+
+    /// debugging function to print out the contents of the layer
+    fn dump(&self) -> Result<()> {
+        println!(
+            "----- image layer for ten {} tli {} seg {} at {} ----",
+            self.tenantid, self.timelineid, self.seg, self.lsn
+        );
+
+        let inner = self.load()?;
+
+        match inner.image_type {
+            ImageType::Blocky { num_blocks } => println!("({}) blocks ", num_blocks),
+            ImageType::NonBlocky => {
+                let (_path, book) = self.open_book()?;
+                let chapter = book.read_chapter(NONBLOCKY_IMAGE_CHAPTER)?;
+                println!("non-blocky ({} bytes)", chapter.len());
+            }
+        }
+
+        Ok(())
+    }
+}
+
+impl ImageLayer {
+    fn path_for(
+        path_or_conf: &PathOrConf,
+        timelineid: ZTimelineId,
+        tenantid: ZTenantId,
+        fname: &ImageFileName,
+    ) -> PathBuf {
+        match path_or_conf {
+            PathOrConf::Path(path) => path.to_path_buf(),
+            PathOrConf::Conf(conf) => conf
+                .timeline_path(&timelineid, &tenantid)
+                .join(fname.to_string()),
+        }
+    }
+
+    /// Create a new image file, using the given array of pages.
+    fn create(
+        conf: &'static PageServerConf,
+        timelineid: ZTimelineId,
+        tenantid: ZTenantId,
+        seg: SegmentTag,
+        lsn: Lsn,
+        base_images: Vec<Bytes>,
+    ) -> Result<ImageLayer> {
+        let image_type = if seg.rel.is_blocky() {
+            let num_blocks: u32 = base_images.len().try_into()?;
+            ImageType::Blocky { num_blocks }
+        } else {
+            assert_eq!(base_images.len(), 1);
+            ImageType::NonBlocky
+        };
+
+        let layer = ImageLayer {
+            path_or_conf: PathOrConf::Conf(conf),
+            timelineid,
+            tenantid,
+            seg,
+            lsn,
+            inner: Mutex::new(ImageLayerInner {
+                loaded: true,
+                image_type: image_type.clone(),
+            }),
+        };
+        let inner = layer.inner.lock().unwrap();
+
+        // Write the images into a file
+        let path = layer.path();
+        // Note: This overwrites any existing file. There shouldn't be any.
+        // FIXME: throw an error instead?
+        let file = File::create(&path)?;
+        let buf_writer = BufWriter::new(file);
+        let book = BookWriter::new(buf_writer, IMAGE_FILE_MAGIC)?;
+
+        let book = match &image_type {
+            ImageType::Blocky { .. } => {
+                let mut chapter = book.new_chapter(BLOCKY_IMAGES_CHAPTER);
+                for block_bytes in base_images {
+                    assert_eq!(block_bytes.len(), BLOCK_SIZE);
+                    chapter.write_all(&block_bytes)?;
+                }
+                chapter.close()?
+            }
+            ImageType::NonBlocky => {
+                let mut chapter = book.new_chapter(NONBLOCKY_IMAGE_CHAPTER);
+                chapter.write_all(&base_images[0])?;
+                chapter.close()?
+            }
+        };
+
+        let mut chapter = book.new_chapter(SUMMARY_CHAPTER);
+        let summary = Summary {
+            tenantid,
+            timelineid,
+            seg,
+
+            lsn,
+        };
+        Summary::ser_into(&summary, &mut chapter)?;
+        let book = chapter.close()?;
+
+        // This flushes the underlying 'buf_writer'.
+        let writer = book.close()?;
+        writer.get_ref().sync_all()?;
+
+        trace!("saved {}", path.display());
+
+        drop(inner);
+
+        Ok(layer)
+    }
+
+    // Create a new image file by materializing every page in a source layer
+    // at given LSN.
+    pub fn create_from_src(
+        conf: &'static PageServerConf,
+        timeline: &LayeredTimeline,
+        src: &dyn Layer,
+        lsn: Lsn,
+    ) -> Result<ImageLayer> {
+        let seg = src.get_seg_tag();
+        let timelineid = timeline.timelineid;
+
+        let startblk;
+        let size;
+        if seg.rel.is_blocky() {
+            size = src.get_seg_size(lsn)?;
+            startblk = seg.segno * RELISH_SEG_SIZE;
+        } else {
+            size = 1;
+            startblk = 0;
+        }
+
+        trace!(
+            "creating new ImageLayer for {} on timeline {} at {}",
+            seg,
+            timelineid,
+            lsn,
+        );
+
+        let mut base_images: Vec<Bytes> = Vec::new();
+        for blknum in startblk..(startblk + size) {
+            let img = timeline.materialize_page(seg, blknum, lsn, &*src)?;
+
+            base_images.push(img);
+        }
+
+        Self::create(conf, timelineid, timeline.tenantid, seg, lsn, base_images)
+    }
+
+    ///
+    /// Load the contents of the file into memory
+    ///
+    fn load(&self) -> Result<MutexGuard<ImageLayerInner>> {
+        // quick exit if already loaded
+        let mut inner = self.inner.lock().unwrap();
+
+        if inner.loaded {
+            return Ok(inner);
+        }
+
+        let (path, book) = self.open_book()?;
+
+        match &self.path_or_conf {
+            PathOrConf::Conf(_) => {
+                let chapter = book.read_chapter(SUMMARY_CHAPTER)?;
+                let actual_summary = Summary::des(&chapter)?;
+
+                let expected_summary = Summary::from(self);
+
+                if actual_summary != expected_summary {
+                    bail!("in-file summary does not match expected summary. actual = {:?} expected = {:?}", actual_summary, expected_summary);
+                }
+            }
+            PathOrConf::Path(path) => {
+                let actual_filename = Path::new(path.file_name().unwrap());
+                let expected_filename = self.filename();
+
+                if actual_filename != expected_filename {
+                    println!(
+                        "warning: filename does not match what is expected from in-file summary"
+                    );
+                    println!("actual: {:?}", actual_filename);
+                    println!("expected: {:?}", expected_filename);
+                }
+            }
+        }
+
+        let image_type = if self.seg.rel.is_blocky() {
+            let chapter = book.chapter_reader(BLOCKY_IMAGES_CHAPTER)?;
+            let images_len = chapter.len();
+            ensure!(images_len % BLOCK_SIZE as u64 == 0);
+            let num_blocks: u32 = (images_len / BLOCK_SIZE as u64).try_into()?;
+            ImageType::Blocky { num_blocks }
+        } else {
+            let _chapter = book.chapter_reader(NONBLOCKY_IMAGE_CHAPTER)?;
+            ImageType::NonBlocky
+        };
+
+        debug!("loaded from {}", &path.display());
+
+        *inner = ImageLayerInner {
+            loaded: true,
+            image_type,
+        };
+
+        Ok(inner)
+    }
+
+    fn open_book(&self) -> Result<(PathBuf, Book<File>)> {
+        let path = self.path();
+
+        let file = File::open(&path)?;
+        let book = Book::new(file)?;
+
+        Ok((path, book))
+    }
+
+    /// Create an ImageLayer struct representing an existing file on disk
+    pub fn new(
+        conf: &'static PageServerConf,
+        timelineid: ZTimelineId,
+        tenantid: ZTenantId,
+        filename: &ImageFileName,
+    ) -> ImageLayer {
+        ImageLayer {
+            path_or_conf: PathOrConf::Conf(conf),
+            timelineid,
+            tenantid,
+            seg: filename.seg,
+            lsn: filename.lsn,
+            inner: Mutex::new(ImageLayerInner {
+                loaded: false,
+                image_type: ImageType::Blocky { num_blocks: 0 },
+            }),
+        }
+    }
+
+    /// Create an ImageLayer struct representing an existing file on disk.
+    ///
+    /// This variant is only used for debugging purposes, by the 'dump_layerfile' binary.
+    pub fn new_for_path(path: &Path, book: &Book<File>) -> Result<ImageLayer> {
+        let chapter = book.read_chapter(SUMMARY_CHAPTER)?;
+        let summary = Summary::des(&chapter)?;
+
+        Ok(ImageLayer {
+            path_or_conf: PathOrConf::Path(path.to_path_buf()),
+            timelineid: summary.timelineid,
+            tenantid: summary.tenantid,
+            seg: summary.seg,
+            lsn: summary.lsn,
+            inner: Mutex::new(ImageLayerInner {
+                loaded: false,
+                image_type: ImageType::Blocky { num_blocks: 0 },
+            }),
+        })
+    }
+
+    fn layer_name(&self) -> ImageFileName {
+        ImageFileName {
+            seg: self.seg,
+            lsn: self.lsn,
+        }
+    }
+
+    /// Path to the layer file in pageserver workdir.
+    pub fn path(&self) -> PathBuf {
+        Self::path_for(
+            &self.path_or_conf,
+            self.timelineid,
+            self.tenantid,
+            &self.layer_name(),
+        )
+    }
+}

pageserver/src/layered_repository/inmemory_layer.rs

@@ -2,23 +2,29 @@
 //! An in-memory layer stores recently received page versions in memory. The page versions
 //! are held in a BTreeMap, and there's another BTreeMap to track the size of the relation.
 //!
+use crate::layered_repository::filename::DeltaFileName;
+use crate::layered_repository::global_layer_map::GLOBAL_OPEN_MEM_USAGE;
 use crate::layered_repository::storage_layer::{
-    Layer, PageReconstructData, PageVersion, SegmentTag, RELISH_SEG_SIZE,
+    Layer, PageReconstructData, PageReconstructResult, PageVersion, SegmentTag, RELISH_SEG_SIZE,
 };
 use crate::layered_repository::LayeredTimeline;
-use crate::layered_repository::SnapshotLayer;
+use crate::layered_repository::{DeltaLayer, ImageLayer};
 use crate::repository::WALRecord;
 use crate::PageServerConf;
 use crate::{ZTenantId, ZTimelineId};
-use anyhow::{bail, Result};
+use anyhow::{ensure, Result};
 use bytes::Bytes;
 use log::*;
-use std::collections::BTreeMap;
-use std::ops::Bound::Included;
-use std::sync::{Arc, Mutex};
+use std::path::PathBuf;
+use std::sync::atomic::Ordering;
+use std::sync::{Arc, RwLock};
+use zenith_utils::vec_map::VecMap;
 
 use zenith_utils::lsn::Lsn;
 
+use super::page_versions::PageVersions;
+use super::storage_layer::Page;
+
 pub struct InMemoryLayer {
     conf: &'static PageServerConf,
     tenantid: ZTenantId,
@@ -27,58 +33,135 @@ pub struct InMemoryLayer {
 
     ///
     /// This layer contains all the changes from 'start_lsn'. The
-    /// start is inclusive. There is no end LSN; we only use in-memory
-    /// layer at the end of a timeline.
+    /// start is inclusive.
     ///
     start_lsn: Lsn,
 
+    /// LSN of the oldest page version stored in this layer
+    oldest_pending_lsn: Lsn,
+
     /// The above fields never change. The parts that do change are in 'inner',
     /// and protected by mutex.
-    inner: Mutex<InMemoryLayerInner>,
+    inner: RwLock<InMemoryLayerInner>,
+
+    /// Predecessor layer might be needed?
+    incremental: bool,
 }
 
 pub struct InMemoryLayerInner {
+    /// Frozen in-memory layers have an exclusive end LSN.
+    /// Writes are only allowed when this is None
+    end_lsn: Option<Lsn>,
+
     /// If this relation was dropped, remember when that happened.
-    drop_lsn: Option<Lsn>,
+    /// The drop LSN is recorded in [`end_lsn`].
+    dropped: bool,
 
     ///
     /// All versions of all pages in the layer are are kept here.
     /// Indexed by block number and LSN.
     ///
-    page_versions: BTreeMap<(u32, Lsn), PageVersion>,
+    page_versions: PageVersions,
 
     ///
     /// `segsizes` tracks the size of the segment at different points in time.
     ///
-    segsizes: BTreeMap<Lsn, u32>,
+    /// For a blocky rel, there is always one entry, at the layer's start_lsn,
+    /// so that determining the size never depends on the predecessor layer. For
+    /// a non-blocky rel, 'segsizes' is not used and is always empty.
+    ///
+    segsizes: VecMap<Lsn, u32>,
+
+    /// Approximate amount of memory used by this layer.
+    ///
+    /// TODO: This is currently a very crude metric, we don't take into account allocator
+    /// overhead, memory fragmentation, memory used by the VecMaps, nor many other things.
+    /// Just the actual # of bytes of a page image (8 kB) or the size of a WAL record.
+    ///
+    /// Whenever this is changed, you must also modify GLOBAL_OPEN_MEM_USAGE accordingly!
+    mem_usage: usize,
+}
+
+impl InMemoryLayerInner {
+    fn assert_writeable(&self) {
+        assert!(self.end_lsn.is_none());
+    }
+
+    fn get_seg_size(&self, lsn: Lsn) -> u32 {
+        // Scan the BTreeMap backwards, starting from the given entry.
+        let slice = self.segsizes.slice_range(..=lsn);
+
+        // We make sure there is always at least one entry
+        if let Some((_entry_lsn, entry)) = slice.last() {
+            *entry
+        } else {
+            panic!("could not find seg size in in-memory layer");
+        }
+    }
+}
+
+impl Drop for InMemoryLayerInner {
+    fn drop(&mut self) {
+        if self.mem_usage > 0 {
+            GLOBAL_OPEN_MEM_USAGE.fetch_sub(self.mem_usage, Ordering::Relaxed);
+            self.mem_usage = 0;
+        }
+    }
 }
 
 impl Layer for InMemoryLayer {
+    // An in-memory layer doesn't really have a filename as it's not stored on disk,
+    // but we construct a filename as if it was a delta layer
+    fn filename(&self) -> PathBuf {
+        let inner = self.inner.read().unwrap();
+
+        let end_lsn;
+        if let Some(drop_lsn) = inner.end_lsn {
+            end_lsn = drop_lsn;
+        } else {
+            end_lsn = Lsn(u64::MAX);
+        }
+
+        let delta_filename = DeltaFileName {
+            seg: self.seg,
+            start_lsn: self.start_lsn,
+            end_lsn,
+            dropped: inner.dropped,
+        }
+        .to_string();
+
+        PathBuf::from(format!("inmem-{}", delta_filename))
+    }
+
+    fn get_tenant_id(&self) -> ZTenantId {
+        self.tenantid
+    }
+
     fn get_timeline_id(&self) -> ZTimelineId {
-        return self.timelineid;
+        self.timelineid
     }
 
     fn get_seg_tag(&self) -> SegmentTag {
-        return self.seg;
+        self.seg
     }
 
     fn get_start_lsn(&self) -> Lsn {
-        return self.start_lsn;
+        self.start_lsn
     }
 
     fn get_end_lsn(&self) -> Lsn {
-        let inner = self.inner.lock().unwrap();
+        let inner = self.inner.read().unwrap();
 
-        if let Some(drop_lsn) = inner.drop_lsn {
-            drop_lsn
+        if let Some(end_lsn) = inner.end_lsn {
+            end_lsn
         } else {
             Lsn(u64::MAX)
         }
     }
 
     fn is_dropped(&self) -> bool {
-        let inner = self.inner.lock().unwrap();
-        inner.drop_lsn.is_some()
+        let inner = self.inner.read().unwrap();
+        inner.dropped
     }
 
     /// Look up given page in the cache.
@@ -87,68 +170,78 @@ impl Layer for InMemoryLayer {
         blknum: u32,
         lsn: Lsn,
         reconstruct_data: &mut PageReconstructData,
-    ) -> Result<Option<Lsn>> {
-        // Scan the BTreeMap backwards, starting from reconstruct_data.lsn.
-        let mut need_base_image_lsn: Option<Lsn> = Some(lsn);
+    ) -> Result<PageReconstructResult> {
+        let mut need_image = true;
 
         assert!(self.seg.blknum_in_seg(blknum));
 
         {
-            let inner = self.inner.lock().unwrap();
-            let minkey = (blknum, Lsn(0));
-            let maxkey = (blknum, lsn);
-            let mut iter = inner
+            let inner = self.inner.read().unwrap();
+
+            // Scan the page versions backwards, starting from `lsn`.
+            let iter = inner
                 .page_versions
-                .range((Included(&minkey), Included(&maxkey)));
-            while let Some(((_blknum, entry_lsn), entry)) = iter.next_back() {
-                if let Some(img) = &entry.page_image {
-                    reconstruct_data.page_img = Some(img.clone());
-                    need_base_image_lsn = None;
-                    break;
-                } else if let Some(rec) = &entry.record {
-                    reconstruct_data.records.push(rec.clone());
-                    if rec.will_init {
-                        // This WAL record initializes the page, so no need to go further back
-                        need_base_image_lsn = None;
+                .get_block_lsn_range(blknum, ..=lsn)
+                .iter()
+                .rev();
+            for (entry_lsn, token) in iter {
+                match inner.page_versions.get_page_version(token)? {
+                    PageVersion::Page(page) => {
+                        reconstruct_data.page_img = Some(page);
+                        need_image = false;
                         break;
-                    } else {
-                        need_base_image_lsn = Some(*entry_lsn);
                     }
-                } else {
-                    // No base image, and no WAL record. Huh?
-                    bail!("no page image or WAL record for requested page");
+                    PageVersion::Wal(rec) => {
+                        let will_init = rec.will_init();
+                        reconstruct_data.records.push((*entry_lsn, rec));
+                        if will_init {
+                            // This WAL record initializes the page, so no need to go further back
+                            need_image = false;
+                            break;
+                        }
+                    }
                 }
             }
-
-            // release lock on 'page_versions'
+            // release lock on 'inner'
         }
 
-        Ok(need_base_image_lsn)
+        // If an older page image is needed to reconstruct the page, let the
+        // caller know
+        if need_image {
+            if self.incremental {
+                Ok(PageReconstructResult::Continue(Lsn(self.start_lsn.0 - 1)))
+            } else {
+                Ok(PageReconstructResult::Missing(self.start_lsn))
+            }
+        } else {
+            Ok(PageReconstructResult::Complete)
+        }
     }
 
     /// Get size of the relation at given LSN
     fn get_seg_size(&self, lsn: Lsn) -> Result<u32> {
-        // Scan the BTreeMap backwards, starting from the given entry.
-        let inner = self.inner.lock().unwrap();
-        let mut iter = inner.segsizes.range((Included(&Lsn(0)), Included(&lsn)));
+        assert!(lsn >= self.start_lsn);
+        ensure!(
+            self.seg.rel.is_blocky(),
+            "get_seg_size() called on a non-blocky rel"
+        );
 
-        if let Some((_entry_lsn, entry)) = iter.next_back() {
-            let result = *entry;
-            drop(inner);
-            trace!("get_seg_size: {} at {} -> {}", self.seg, lsn, result);
-            Ok(result)
-        } else {
-            bail!("No size found for {} at {} in memory", self.seg, lsn);
-        }
+        let inner = self.inner.read().unwrap();
+        Ok(inner.get_seg_size(lsn))
     }
 
     /// Does this segment exist at given LSN?
     fn get_seg_exists(&self, lsn: Lsn) -> Result<bool> {
-        let inner = self.inner.lock().unwrap();
+        let inner = self.inner.read().unwrap();
+
+        // If the segment created after requested LSN,
+        // it doesn't exist in the layer. But we shouldn't
+        // have requested it in the first place.
+        assert!(lsn >= self.start_lsn);
 
         // Is the requested LSN after the segment was dropped?
-        if let Some(drop_lsn) = inner.drop_lsn {
-            if lsn >= drop_lsn {
+        if let Some(end_lsn) = inner.end_lsn {
+            if lsn >= end_lsn {
                 return Ok(false);
             }
         }
@@ -156,9 +249,68 @@ impl Layer for InMemoryLayer {
         // Otherwise, it exists
         Ok(true)
     }
+
+    /// Cannot unload anything in an in-memory layer, since there's no backing
+    /// store. To release memory used by an in-memory layer, use 'freeze' to turn
+    /// it into an on-disk layer.
+    fn unload(&self) -> Result<()> {
+        Ok(())
+    }
+
+    /// Nothing to do here. When you drop the last reference to the layer, it will
+    /// be deallocated.
+    fn delete(&self) -> Result<()> {
+        Ok(())
+    }
+
+    fn is_incremental(&self) -> bool {
+        self.incremental
+    }
+
+    /// debugging function to print out the contents of the layer
+    fn dump(&self) -> Result<()> {
+        let inner = self.inner.read().unwrap();
+
+        let end_str = inner
+            .end_lsn
+            .as_ref()
+            .map(Lsn::to_string)
+            .unwrap_or_default();
+
+        println!(
+            "----- in-memory layer for tli {} seg {} {}-{} {} ----",
+            self.timelineid, self.seg, self.start_lsn, end_str, inner.dropped,
+        );
+
+        for (k, v) in inner.segsizes.as_slice() {
+            println!("segsizes {}: {}", k, v);
+        }
+
+        for (blknum, lsn, token) in inner.page_versions.ordered_page_version_iter(None) {
+            let pv_description = match inner.page_versions.get_page_version(token)? {
+                PageVersion::Page(_img) => "page",
+                PageVersion::Wal(_rec) => "wal",
+            };
+
+            println!("blk {} at {}: {}\n", blknum, lsn, pv_description);
+        }
+
+        Ok(())
+    }
+}
+
+/// A result of an inmemory layer data being written to disk.
+pub struct LayersOnDisk {
+    pub delta_layers: Vec<DeltaLayer>,
+    pub image_layers: Vec<ImageLayer>,
 }
 
 impl InMemoryLayer {
+    /// Return the oldest page version that's stored in this layer
+    pub fn get_oldest_pending_lsn(&self) -> Lsn {
+        self.oldest_pending_lsn
+    }
+
     ///
     /// Create a new, empty, in-memory layer
     ///
@@ -168,6 +320,7 @@ impl InMemoryLayer {
         tenantid: ZTenantId,
         seg: SegmentTag,
         start_lsn: Lsn,
+        oldest_pending_lsn: Lsn,
     ) -> Result<InMemoryLayer> {
         trace!(
             "initializing new empty InMemoryLayer for writing {} on timeline {} at {}",
@@ -176,16 +329,26 @@ impl InMemoryLayer {
             start_lsn
         );
 
+        // The segment is initially empty, so initialize 'segsizes' with 0.
+        let mut segsizes = VecMap::default();
+        if seg.rel.is_blocky() {
+            segsizes.append(start_lsn, 0).unwrap();
+        }
+
         Ok(InMemoryLayer {
             conf,
             timelineid,
             tenantid,
             seg,
             start_lsn,
-            inner: Mutex::new(InMemoryLayerInner {
-                drop_lsn: None,
-                page_versions: BTreeMap::new(),
-                segsizes: BTreeMap::new(),
+            oldest_pending_lsn,
+            incremental: false,
+            inner: RwLock::new(InMemoryLayerInner {
+                end_lsn: None,
+                dropped: false,
+                page_versions: PageVersions::default(),
+                segsizes,
+                mem_usage: 0,
             }),
         })
     }
@@ -193,32 +356,18 @@ impl InMemoryLayer {
     // Write operations
 
     /// Remember new page version, as a WAL record over previous version
-    pub fn put_wal_record(&self, blknum: u32, rec: WALRecord) -> Result<()> {
-        self.put_page_version(
-            blknum,
-            rec.lsn,
-            PageVersion {
-                page_image: None,
-                record: Some(rec),
-            },
-        )
+    pub fn put_wal_record(&self, lsn: Lsn, blknum: u32, rec: WALRecord) -> u32 {
+        self.put_page_version(blknum, lsn, PageVersion::Wal(rec))
     }
 
     /// Remember new page version, as a full page image
-    pub fn put_page_image(&self, blknum: u32, lsn: Lsn, img: Bytes) -> Result<()> {
-        self.put_page_version(
-            blknum,
-            lsn,
-            PageVersion {
-                page_image: Some(img),
-                record: None,
-            },
-        )
+    pub fn put_page_image(&self, blknum: u32, lsn: Lsn, img: Bytes) -> u32 {
+        self.put_page_version(blknum, lsn, PageVersion::Page(Page::from_bytes(&img)))
     }
 
     /// Common subroutine of the public put_wal_record() and put_page_image() functions.
     /// Adds the page version to the in-memory tree
-    pub fn put_page_version(&self, blknum: u32, lsn: Lsn, pv: PageVersion) -> Result<()> {
+    pub fn put_page_version(&self, blknum: u32, lsn: Lsn, pv: PageVersion) -> u32 {
         assert!(self.seg.blknum_in_seg(blknum));
 
         trace!(
@@ -228,9 +377,17 @@ impl InMemoryLayer {
             self.timelineid,
             lsn
         );
-        let mut inner = self.inner.lock().unwrap();
+        let mut inner = self.inner.write().unwrap();
 
-        let old = inner.page_versions.insert((blknum, lsn), pv);
+        inner.assert_writeable();
+
+        let mut mem_usage = 0;
+        mem_usage += match &pv {
+            PageVersion::Page(page) => page.image().len(),
+            PageVersion::Wal(rec) => rec.rec().len(),
+        };
+
+        let old = inner.page_versions.append_or_update_last(blknum, lsn, pv);
 
         if old.is_some() {
             // We already had an entry for this LSN. That's odd..
@@ -240,19 +397,16 @@ impl InMemoryLayer {
             );
         }
 
+        inner.mem_usage += mem_usage;
+        GLOBAL_OPEN_MEM_USAGE.fetch_add(mem_usage, Ordering::Relaxed);
+
         // Also update the relation size, if this extended the relation.
         if self.seg.rel.is_blocky() {
             let newsize = blknum - self.seg.segno * RELISH_SEG_SIZE + 1;
 
-            let mut iter = inner.segsizes.range((Included(&Lsn(0)), Included(&lsn)));
-
-            let oldsize;
-            if let Some((_entry_lsn, entry)) = iter.next_back() {
-                oldsize = *entry;
-            } else {
-                oldsize = 0;
-                //bail!("No old size found for {} at {}", self.tag, lsn);
-            }
+            // use inner get_seg_size, since calling self.get_seg_size will try to acquire the lock,
+            // which we've just acquired above
+            let oldsize = inner.get_seg_size(lsn);
             if newsize > oldsize {
                 trace!(
                     "enlarging segment {} from {} to {} blocks at {}",
@@ -261,231 +415,269 @@ impl InMemoryLayer {
                     newsize,
                     lsn
                 );
-                inner.segsizes.insert(lsn, newsize);
+
+                // If we are extending the relation by more than one page, initialize the "gap"
+                // with zeros
+                //
+                // XXX: What if the caller initializes the gap with subsequent call with same LSN?
+                // I don't think that can happen currently, but that is highly dependent on how
+                // PostgreSQL writes its WAL records and there's no guarantee of it. If it does
+                // happen, we would hit the "page version already exists" warning above on the
+                // subsequent call to initialize the gap page.
+                let gapstart = self.seg.segno * RELISH_SEG_SIZE + oldsize;
+                for gapblknum in gapstart..blknum {
+                    let zeropv = PageVersion::Page(Page::zero_page());
+                    trace!(
+                        "filling gap blk {} with zeros for write of {}",
+                        gapblknum,
+                        blknum
+                    );
+                    let old = inner
+                        .page_versions
+                        .append_or_update_last(gapblknum, lsn, zeropv);
+                    // We already had an entry for this LSN. That's odd..
+
+                    if old.is_some() {
+                        warn!(
+                            "Page version of rel {} blk {} at {} already exists",
+                            self.seg.rel, blknum, lsn
+                        );
+                    }
+                }
+
+                inner.segsizes.append_or_update_last(lsn, newsize).unwrap();
+                return newsize - oldsize;
             }
         }
 
-        Ok(())
+        0
     }
 
     /// Remember that the relation was truncated at given LSN
-    pub fn put_truncation(&self, lsn: Lsn, segsize: u32) -> anyhow::Result<()> {
-        let mut inner = self.inner.lock().unwrap();
-        let old = inner.segsizes.insert(lsn, segsize);
+    pub fn put_truncation(&self, lsn: Lsn, segsize: u32) {
+        assert!(
+            self.seg.rel.is_blocky(),
+            "put_truncation() called on a non-blocky rel"
+        );
+
+        let mut inner = self.inner.write().unwrap();
+        inner.assert_writeable();
+
+        // check that this we truncate to a smaller size than segment was before the truncation
+        let oldsize = inner.get_seg_size(lsn);
+        assert!(segsize < oldsize);
+
+        let old = inner.segsizes.append_or_update_last(lsn, segsize).unwrap();
 
         if old.is_some() {
             // We already had an entry for this LSN. That's odd..
             warn!("Inserting truncation, but had an entry for the LSN already");
         }
-
-        Ok(())
     }
 
     /// Remember that the segment was dropped at given LSN
-    pub fn put_unlink(&self, lsn: Lsn) -> anyhow::Result<()> {
-        let mut inner = self.inner.lock().unwrap();
+    pub fn drop_segment(&self, lsn: Lsn) {
+        let mut inner = self.inner.write().unwrap();
 
-        assert!(inner.drop_lsn.is_none());
-        inner.drop_lsn = Some(lsn);
+        assert!(inner.end_lsn.is_none());
+        assert!(!inner.dropped);
+        inner.dropped = true;
+        assert!(self.start_lsn < lsn);
+        inner.end_lsn = Some(lsn);
 
-        info!("dropped segment {} at {}", self.seg, lsn);
-
-        Ok(())
+        trace!("dropped segment {} at {}", self.seg, lsn);
     }
 
     ///
     /// Initialize a new InMemoryLayer for, by copying the state at the given
     /// point in time from given existing layer.
     ///
-    pub fn copy_snapshot(
+    pub fn create_successor_layer(
         conf: &'static PageServerConf,
-        timeline: &LayeredTimeline,
-        src: &dyn Layer,
+        src: Arc<dyn Layer>,
         timelineid: ZTimelineId,
         tenantid: ZTenantId,
-        lsn: Lsn,
+        start_lsn: Lsn,
+        oldest_pending_lsn: Lsn,
     ) -> Result<InMemoryLayer> {
-        trace!(
-            "initializing new InMemoryLayer for writing {} on timeline {} at {}",
-            src.get_seg_tag(),
-            timelineid,
-            lsn
-        );
-        let mut page_versions = BTreeMap::new();
-        let mut segsizes = BTreeMap::new();
-
         let seg = src.get_seg_tag();
 
-        let startblk;
-        let size;
-        if seg.rel.is_blocky() {
-            size = src.get_seg_size(lsn)?;
-            segsizes.insert(lsn, size);
-            startblk = seg.segno * RELISH_SEG_SIZE;
-        } else {
-            size = 1;
-            startblk = 0;
-        }
+        assert!(oldest_pending_lsn.is_aligned());
+        assert!(oldest_pending_lsn >= start_lsn);
 
-        for blknum in startblk..(startblk + size) {
-            let img = timeline.materialize_page(seg, blknum, lsn, src)?;
-            let pv = PageVersion {
-                page_image: Some(img),
-                record: None,
-            };
-            page_versions.insert((blknum, lsn), pv);
+        trace!(
+            "initializing new InMemoryLayer for writing {} on timeline {} at {}",
+            seg,
+            timelineid,
+            start_lsn,
+        );
+
+        // Copy the segment size at the start LSN from the predecessor layer.
+        let mut segsizes = VecMap::default();
+        if seg.rel.is_blocky() {
+            let size = src.get_seg_size(start_lsn)?;
+            segsizes.append(start_lsn, size).unwrap();
         }
 
         Ok(InMemoryLayer {
             conf,
             timelineid,
             tenantid,
-            seg: src.get_seg_tag(),
-            start_lsn: lsn,
-            inner: Mutex::new(InMemoryLayerInner {
-                drop_lsn: None,
-                page_versions: page_versions,
-                segsizes: segsizes,
+            seg,
+            start_lsn,
+            oldest_pending_lsn,
+            incremental: true,
+            inner: RwLock::new(InMemoryLayerInner {
+                end_lsn: None,
+                dropped: false,
+                page_versions: PageVersions::default(),
+                segsizes,
+                mem_usage: 0,
             }),
         })
     }
 
+    pub fn is_writeable(&self) -> bool {
+        let inner = self.inner.read().unwrap();
+        inner.end_lsn.is_none()
+    }
+
+    /// Make the layer non-writeable. Only call once.
+    /// Records the end_lsn for non-dropped layers.
+    /// `end_lsn` is inclusive
+    pub fn freeze(&self, end_lsn: Lsn) {
+        let mut inner = self.inner.write().unwrap();
+
+        if inner.end_lsn.is_some() {
+            assert!(inner.dropped);
+        } else {
+            assert!(!inner.dropped);
+            assert!(self.start_lsn < end_lsn + 1);
+            inner.end_lsn = Some(Lsn(end_lsn.0 + 1));
+
+            if let Some((lsn, _)) = inner.segsizes.as_slice().last() {
+                assert!(lsn <= &end_lsn, "{:?} {:?}", lsn, end_lsn);
+            }
+
+            for (_blk, lsn, _pv) in inner.page_versions.ordered_page_version_iter(None) {
+                assert!(lsn <= end_lsn);
+            }
+
+            // It's a bit premature to subtract the global mem usage here already.
+            // This layer consumes memory until it's written out to disk and dropped.
+            // But GLOBAL_OPEN_MEM_USAGE is used to trigger layer eviction, if there are
+            // too many open layers, and from that point of view this should no longer be
+            // counted against the global mem usage.
+            if inner.mem_usage > 0 {
+                GLOBAL_OPEN_MEM_USAGE.fetch_sub(inner.mem_usage, Ordering::Relaxed);
+                inner.mem_usage = 0;
+            }
+        }
+    }
+
+    /// Write the this frozen in-memory layer to disk.
     ///
-    /// Write the this in-memory layer to disk, as a snapshot layer.
-    ///
-    /// The cutoff point for the layer that's written to disk is 'end_lsn'.
-    ///
-    /// Returns new layers that replace this one. Always returns a
-    /// SnapshotLayer containing the page versions that were written to disk,
-    /// but if there were page versions newer than 'end_lsn', also return a new
-    /// in-memory layer containing those page versions. The caller replaces
-    /// this layer with the returned layers in the layer map.
-    ///
-    pub fn freeze(
-        &self,
-        cutoff_lsn: Lsn,
-        // This is needed just to call materialize_page()
-        timeline: &LayeredTimeline,
-    ) -> Result<(Option<Arc<SnapshotLayer>>, Option<Arc<InMemoryLayer>>)> {
-        info!(
-            "freezing in memory layer for {} on timeline {} at {}",
-            self.seg, self.timelineid, cutoff_lsn
+    /// Returns new layers that replace this one.
+    /// If not dropped, returns a new image layer containing the page versions
+    /// at the `end_lsn`. Can also return a DeltaLayer that includes all the
+    /// WAL records between start and end LSN. (The delta layer is not needed
+    /// when a new relish is created with a single LSN, so that the start and
+    /// end LSN are the same.)
+    pub fn write_to_disk(&self, timeline: &LayeredTimeline) -> Result<LayersOnDisk> {
+        trace!(
+            "write_to_disk {} get_end_lsn is {}",
+            self.filename().display(),
+            self.get_end_lsn()
         );
 
-        let inner = self.inner.lock().unwrap();
+        // Grab the lock in read-mode. We hold it over the I/O, but because this
+        // layer is not writeable anymore, no one should be trying to acquire the
+        // write lock on it, so we shouldn't block anyone. There's one exception
+        // though: another thread might have grabbed a reference to this layer
+        // in `get_layer_for_write' just before the checkpointer called
+        // `freeze`, and then `write_to_disk` on it. When the thread gets the
+        // lock, it will see that it's not writeable anymore and retry, but it
+        // would have to wait until we release it. That race condition is very
+        // rare though, so we just accept the potential latency hit for now.
+        let inner = self.inner.read().unwrap();
+        let end_lsn_exclusive = inner.end_lsn.unwrap();
 
-        // Normally, use the cutoff LSN as the end of the frozen layer.
-        // But if the relation was dropped, we know that there are no
-        // more changes coming in for it, and in particular we know that
-        // there are no changes "in flight" for the LSN anymore, so we use
-        // the drop LSN instead. The drop-LSN could be ahead of the
-        // caller-specified LSN!
-        let dropped = inner.drop_lsn.is_some();
-        let end_lsn = if dropped {
-            inner.drop_lsn.unwrap()
-        } else {
-            cutoff_lsn
-        };
-
-        // Divide all the page versions into old and new at the 'end_lsn' cutoff point.
-        let mut before_page_versions;
-        let mut before_segsizes;
-        let mut after_page_versions;
-        let mut after_segsizes;
-        if !dropped {
-            before_segsizes = BTreeMap::new();
-            after_segsizes = BTreeMap::new();
-            for (lsn, size) in inner.segsizes.iter() {
-                if *lsn > end_lsn {
-                    after_segsizes.insert(*lsn, *size);
-                } else {
-                    before_segsizes.insert(*lsn, *size);
-                }
-            }
-
-            before_page_versions = BTreeMap::new();
-            after_page_versions = BTreeMap::new();
-            for ((blknum, lsn), pv) in inner.page_versions.iter() {
-                if *lsn > end_lsn {
-                    after_page_versions.insert((*blknum, *lsn), pv.clone());
-                } else {
-                    before_page_versions.insert((*blknum, *lsn), pv.clone());
-                }
-            }
-        } else {
-            before_page_versions = inner.page_versions.clone();
-            before_segsizes = inner.segsizes.clone();
-            after_segsizes = BTreeMap::new();
-            after_page_versions = BTreeMap::new();
-        }
-
-        // we can release the lock now.
-        drop(inner);
-
-        // Write the page versions before the cutoff to disk.
-        let snapfile = SnapshotLayer::create(
-            self.conf,
-            self.timelineid,
-            self.tenantid,
-            self.seg,
-            self.start_lsn,
-            end_lsn,
-            dropped,
-            before_page_versions,
-            before_segsizes,
-        )?;
-
-        // If there were any "new" page versions, initialize a new in-memory layer to hold
-        // them
-        let new_open = if !after_segsizes.is_empty() || !after_page_versions.is_empty() {
-            info!("created new in-mem layer for {} {}-", self.seg, end_lsn);
-
-            let new_open = Self::copy_snapshot(
+        if inner.dropped {
+            let delta_layer = DeltaLayer::create(
                 self.conf,
-                timeline,
-                &snapfile,
                 self.timelineid,
                 self.tenantid,
-                end_lsn,
+                self.seg,
+                self.start_lsn,
+                end_lsn_exclusive,
+                true,
+                &inner.page_versions,
+                None,
+                inner.segsizes.clone(),
             )?;
-            let mut new_inner = new_open.inner.lock().unwrap();
-            new_inner.page_versions.append(&mut after_page_versions);
-            new_inner.segsizes.append(&mut after_segsizes);
-            drop(new_inner);
+            trace!(
+                "freeze: created delta layer for dropped segment {} {}-{}",
+                self.seg,
+                self.start_lsn,
+                end_lsn_exclusive
+            );
+            return Ok(LayersOnDisk {
+                delta_layers: vec![delta_layer],
+                image_layers: Vec::new(),
+            });
+        }
 
-            Some(Arc::new(new_open))
+        // Since `end_lsn` is inclusive, subtract 1.
+        // We want to make an ImageLayer for the last included LSN,
+        // so the DeltaLayer should exclude that LSN.
+        let end_lsn_inclusive = Lsn(end_lsn_exclusive.0 - 1);
+
+        let mut delta_layers = Vec::new();
+
+        if self.start_lsn != end_lsn_inclusive {
+            let (segsizes, _) = inner.segsizes.split_at(&end_lsn_exclusive);
+            // Write the page versions before the cutoff to disk.
+            let delta_layer = DeltaLayer::create(
+                self.conf,
+                self.timelineid,
+                self.tenantid,
+                self.seg,
+                self.start_lsn,
+                end_lsn_inclusive,
+                false,
+                &inner.page_versions,
+                Some(end_lsn_inclusive),
+                segsizes,
+            )?;
+            delta_layers.push(delta_layer);
+            trace!(
+                "freeze: created delta layer {} {}-{}",
+                self.seg,
+                self.start_lsn,
+                end_lsn_inclusive
+            );
         } else {
-            None
-        };
+            assert!(inner
+                .page_versions
+                .ordered_page_version_iter(None)
+                .next()
+                .is_none());
+        }
 
-        let new_historic = Some(Arc::new(snapfile));
+        drop(inner);
 
-        Ok((new_historic, new_open))
-    }
-
-    /// debugging function to print out the contents of the layer
-    #[allow(unused)]
-    pub fn dump(&self) -> String {
-        let mut result = format!(
-            "----- inmemory layer for {} {}-> ----\n",
-            self.seg, self.start_lsn
+        // Write a new base image layer at the cutoff point
+        let image_layer =
+            ImageLayer::create_from_src(self.conf, timeline, self, end_lsn_inclusive)?;
+        trace!(
+            "freeze: created image layer {} at {}",
+            self.seg,
+            end_lsn_inclusive
         );
 
-        let inner = self.inner.lock().unwrap();
-
-        for (k, v) in inner.segsizes.iter() {
-            result += &format!("{}: {}\n", k, v);
-        }
-        for (k, v) in inner.page_versions.iter() {
-            result += &format!(
-                "blk {} at {}: {}/{}\n",
-                k.0,
-                k.1,
-                v.page_image.is_some(),
-                v.record.is_some()
-            );
-        }
-
-        result
+        Ok(LayersOnDisk {
+            delta_layers,
+            image_layers: vec![image_layer],
+        })
     }
 }

pageserver/src/layered_repository/interval_tree.rs

@@ -0,0 +1,468 @@
+///
+/// IntervalTree is data structure for holding intervals. It is generic
+/// to make unit testing possible, but the only real user of it is the layer map,
+///
+/// It's inspired by the "segment tree" or a "statistic tree" as described in
+/// https://en.wikipedia.org/wiki/Segment_tree. However, we use a B-tree to hold
+/// the points instead of a binary tree. This is called an "interval tree" instead
+/// of "segment tree" because the term "segment" is already using Zenith to mean
+/// something else. To add to the confusion, there is another data structure known
+/// as "interval tree" out there (see https://en.wikipedia.org/wiki/Interval_tree),
+/// for storing intervals, but this isn't that.
+///
+/// The basic idea is to have a B-tree of "interesting Points". At each Point,
+/// there is a list of intervals that contain the point. The Points are formed
+/// from the start bounds of each interval; there is a Point for each distinct
+/// start bound.
+///
+/// Operations:
+///
+/// To find intervals that contain a given point, you search the b-tree to find
+/// the nearest Point <= search key. Then you just return the list of intervals.
+///
+/// To insert an interval, find the Point with start key equal to the inserted item.
+/// If the Point doesn't exist yet, create it, by copying all the items from the
+/// previous Point that cover the new Point. Then walk right, inserting the new
+/// interval to all the Points that are contained by the new interval (including the
+/// newly created Point).
+///
+/// To remove an interval, you scan the tree for all the Points that are contained by
+/// the removed interval, and remove it from the list in each Point.
+///
+/// Requirements and assumptions:
+///
+/// - Can store overlapping items
+/// - But there are not many overlapping items
+/// - The interval bounds don't change after it is added to the tree
+/// - Intervals are uniquely identified by pointer equality. You must not be insert the
+///   same interval object twice, and `remove` uses pointer equality to remove the right
+///   interval. It is OK to have two intervals with the same bounds, however.
+///
+use std::collections::BTreeMap;
+use std::fmt::Debug;
+use std::ops::Range;
+use std::sync::Arc;
+
+pub struct IntervalTree<I: ?Sized>
+where
+    I: IntervalItem,
+{
+    points: BTreeMap<I::Key, Point<I>>,
+}
+
+struct Point<I: ?Sized> {
+    /// All intervals that contain this point, in no particular order.
+    ///
+    /// We assume that there aren't a lot of overlappingg intervals, so that this vector
+    /// never grows very large. If that assumption doesn't hold, we could keep this ordered
+    /// by the end bound, to speed up `search`. But as long as there are only a few elements,
+    /// a linear search is OK.
+    elements: Vec<Arc<I>>,
+}
+
+/// Abstraction for an interval that can be stored in the tree
+///
+/// The start bound is inclusive and the end bound is exclusive. End must be greater
+/// than start.
+pub trait IntervalItem {
+    type Key: Ord + Copy + Debug + Sized;
+
+    fn start_key(&self) -> Self::Key;
+    fn end_key(&self) -> Self::Key;
+
+    fn bounds(&self) -> Range<Self::Key> {
+        self.start_key()..self.end_key()
+    }
+}
+
+impl<I: ?Sized> IntervalTree<I>
+where
+    I: IntervalItem,
+{
+    /// Return an element that contains 'key', or precedes it.
+    ///
+    /// If there are multiple candidates, returns the one with the highest 'end' key.
+    pub fn search(&self, key: I::Key) -> Option<Arc<I>> {
+        // Find the greatest point that precedes or is equal to the search key. If there is
+        // none, returns None.
+        let (_, p) = self.points.range(..=key).next_back()?;
+
+        // Find the element with the highest end key at this point
+        let highest_item = p
+            .elements
+            .iter()
+            .reduce(|a, b| {
+                // starting with Rust 1.53, could use `std::cmp::min_by_key` here
+                if a.end_key() > b.end_key() {
+                    a
+                } else {
+                    b
+                }
+            })
+            .unwrap();
+        Some(Arc::clone(highest_item))
+    }
+
+    /// Iterate over all items with start bound >= 'key'
+    pub fn iter_newer(&self, key: I::Key) -> IntervalIter<I> {
+        IntervalIter {
+            point_iter: self.points.range(key..),
+            elem_iter: None,
+        }
+    }
+
+    /// Iterate over all items
+    pub fn iter(&self) -> IntervalIter<I> {
+        IntervalIter {
+            point_iter: self.points.range(..),
+            elem_iter: None,
+        }
+    }
+
+    pub fn insert(&mut self, item: Arc<I>) {
+        let start_key = item.start_key();
+        let end_key = item.end_key();
+        assert!(start_key < end_key);
+        let bounds = start_key..end_key;
+
+        // Find the starting point and walk forward from there
+        let mut found_start_point = false;
+        let iter = self.points.range_mut(bounds);
+        for (point_key, point) in iter {
+            if *point_key == start_key {
+                found_start_point = true;
+                // It is an error to insert the same item to the tree twice.
+                assert!(
+                    !point.elements.iter().any(|x| Arc::ptr_eq(x, &item)),
+                    "interval is already in the tree"
+                );
+            }
+            point.elements.push(Arc::clone(&item));
+        }
+        if !found_start_point {
+            // Create a new Point for the starting point
+
+            // Look at the previous point, and copy over elements that overlap with this
+            // new point
+            let mut new_elements: Vec<Arc<I>> = Vec::new();
+            if let Some((_, prev_point)) = self.points.range(..start_key).next_back() {
+                let overlapping_prev_elements = prev_point
+                    .elements
+                    .iter()
+                    .filter(|x| x.bounds().contains(&start_key))
+                    .cloned();
+
+                new_elements.extend(overlapping_prev_elements);
+            }
+            new_elements.push(item);
+
+            let new_point = Point {
+                elements: new_elements,
+            };
+            self.points.insert(start_key, new_point);
+        }
+    }
+
+    pub fn remove(&mut self, item: &Arc<I>) {
+        // range search points
+        let start_key = item.start_key();
+        let end_key = item.end_key();
+        let bounds = start_key..end_key;
+
+        let mut points_to_remove: Vec<I::Key> = Vec::new();
+        let mut found_start_point = false;
+        for (point_key, point) in self.points.range_mut(bounds) {
+            if *point_key == start_key {
+                found_start_point = true;
+            }
+            let len_before = point.elements.len();
+            point.elements.retain(|other| !Arc::ptr_eq(other, item));
+            let len_after = point.elements.len();
+            assert_eq!(len_after + 1, len_before);
+            if len_after == 0 {
+                points_to_remove.push(*point_key);
+            }
+        }
+        assert!(found_start_point);
+
+        for k in points_to_remove {
+            self.points.remove(&k).unwrap();
+        }
+    }
+}
+
+pub struct IntervalIter<'a, I: ?Sized>
+where
+    I: IntervalItem,
+{
+    point_iter: std::collections::btree_map::Range<'a, I::Key, Point<I>>,
+    elem_iter: Option<(I::Key, std::slice::Iter<'a, Arc<I>>)>,
+}
+
+impl<'a, I> Iterator for IntervalIter<'a, I>
+where
+    I: IntervalItem + ?Sized,
+{
+    type Item = Arc<I>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        // Iterate over all elements in all the points in 'point_iter'. To avoid
+        // returning the same element twice, we only return each element at its
+        // starting point.
+        loop {
+            // Return next remaining element from the current point
+            if let Some((point_key, elem_iter)) = &mut self.elem_iter {
+                for elem in elem_iter {
+                    if elem.start_key() == *point_key {
+                        return Some(Arc::clone(elem));
+                    }
+                }
+            }
+            // No more elements at this point. Move to next point.
+            if let Some((point_key, point)) = self.point_iter.next() {
+                self.elem_iter = Some((*point_key, point.elements.iter()));
+                continue;
+            } else {
+                // No more points, all done
+                return None;
+            }
+        }
+    }
+}
+
+impl<I: ?Sized> Default for IntervalTree<I>
+where
+    I: IntervalItem,
+{
+    fn default() -> Self {
+        IntervalTree {
+            points: BTreeMap::new(),
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::fmt;
+
+    #[derive(Debug)]
+    struct MockItem {
+        start_key: u32,
+        end_key: u32,
+        val: String,
+    }
+    impl IntervalItem for MockItem {
+        type Key = u32;
+
+        fn start_key(&self) -> u32 {
+            self.start_key
+        }
+        fn end_key(&self) -> u32 {
+            self.end_key
+        }
+    }
+    impl MockItem {
+        fn new(start_key: u32, end_key: u32) -> Self {
+            MockItem {
+                start_key,
+                end_key,
+                val: format!("{}-{}", start_key, end_key),
+            }
+        }
+        fn new_str(start_key: u32, end_key: u32, val: &str) -> Self {
+            MockItem {
+                start_key,
+                end_key,
+                val: format!("{}-{}: {}", start_key, end_key, val),
+            }
+        }
+    }
+    impl fmt::Display for MockItem {
+        fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+            write!(f, "{}", self.val)
+        }
+    }
+    #[rustfmt::skip]
+    fn assert_search(
+        tree: &IntervalTree<MockItem>,
+        key: u32,
+        expected: &[&str],
+    ) -> Option<Arc<MockItem>> {
+        if let Some(v) = tree.search(key) {
+            let vstr = v.to_string();
+
+            assert!(!expected.is_empty(), "search with {} returned {}, expected None", key, v);
+            assert!(
+                expected.contains(&vstr.as_str()),
+                "search with {} returned {}, expected one of: {:?}",
+                key, v, expected,
+            );
+
+            Some(v)
+        } else {
+            assert!(
+                expected.is_empty(),
+                "search with {} returned None, expected one of {:?}",
+                key, expected
+            );
+            None
+        }
+    }
+
+    fn assert_contents(tree: &IntervalTree<MockItem>, expected: &[&str]) {
+        let mut contents: Vec<String> = tree.iter().map(|e| e.to_string()).collect();
+        contents.sort();
+        assert_eq!(contents, expected);
+    }
+
+    fn dump_tree(tree: &IntervalTree<MockItem>) {
+        for (point_key, point) in tree.points.iter() {
+            print!("{}:", point_key);
+            for e in point.elements.iter() {
+                print!(" {}", e);
+            }
+            println!();
+        }
+    }
+
+    #[test]
+    fn test_interval_tree_simple() {
+        let mut tree: IntervalTree<MockItem> = IntervalTree::default();
+
+        // Simple, non-overlapping ranges.
+        tree.insert(Arc::new(MockItem::new(10, 11)));
+        tree.insert(Arc::new(MockItem::new(11, 12)));
+        tree.insert(Arc::new(MockItem::new(12, 13)));
+        tree.insert(Arc::new(MockItem::new(18, 19)));
+        tree.insert(Arc::new(MockItem::new(17, 18)));
+        tree.insert(Arc::new(MockItem::new(15, 16)));
+
+        assert_search(&tree, 9, &[]);
+        assert_search(&tree, 10, &["10-11"]);
+        assert_search(&tree, 11, &["11-12"]);
+        assert_search(&tree, 12, &["12-13"]);
+        assert_search(&tree, 13, &["12-13"]);
+        assert_search(&tree, 14, &["12-13"]);
+        assert_search(&tree, 15, &["15-16"]);
+        assert_search(&tree, 16, &["15-16"]);
+        assert_search(&tree, 17, &["17-18"]);
+        assert_search(&tree, 18, &["18-19"]);
+        assert_search(&tree, 19, &["18-19"]);
+        assert_search(&tree, 20, &["18-19"]);
+
+        // remove a few entries and search around them again
+        tree.remove(&assert_search(&tree, 10, &["10-11"]).unwrap()); // first entry
+        tree.remove(&assert_search(&tree, 12, &["12-13"]).unwrap()); // entry in the middle
+        tree.remove(&assert_search(&tree, 18, &["18-19"]).unwrap()); // last entry
+        assert_search(&tree, 9, &[]);
+        assert_search(&tree, 10, &[]);
+        assert_search(&tree, 11, &["11-12"]);
+        assert_search(&tree, 12, &["11-12"]);
+        assert_search(&tree, 14, &["11-12"]);
+        assert_search(&tree, 15, &["15-16"]);
+        assert_search(&tree, 17, &["17-18"]);
+        assert_search(&tree, 18, &["17-18"]);
+    }
+
+    #[test]
+    fn test_interval_tree_overlap() {
+        let mut tree: IntervalTree<MockItem> = IntervalTree::default();
+
+        // Overlapping items
+        tree.insert(Arc::new(MockItem::new(22, 24)));
+        tree.insert(Arc::new(MockItem::new(23, 25)));
+        let x24_26 = Arc::new(MockItem::new(24, 26));
+        tree.insert(Arc::clone(&x24_26));
+        let x26_28 = Arc::new(MockItem::new(26, 28));
+        tree.insert(Arc::clone(&x26_28));
+        tree.insert(Arc::new(MockItem::new(25, 27)));
+
+        assert_search(&tree, 22, &["22-24"]);
+        assert_search(&tree, 23, &["22-24", "23-25"]);
+        assert_search(&tree, 24, &["23-25", "24-26"]);
+        assert_search(&tree, 25, &["24-26", "25-27"]);
+        assert_search(&tree, 26, &["25-27", "26-28"]);
+        assert_search(&tree, 27, &["26-28"]);
+        assert_search(&tree, 28, &["26-28"]);
+        assert_search(&tree, 29, &["26-28"]);
+
+        tree.remove(&x24_26);
+        tree.remove(&x26_28);
+        assert_search(&tree, 23, &["22-24", "23-25"]);
+        assert_search(&tree, 24, &["23-25"]);
+        assert_search(&tree, 25, &["25-27"]);
+        assert_search(&tree, 26, &["25-27"]);
+        assert_search(&tree, 27, &["25-27"]);
+        assert_search(&tree, 28, &["25-27"]);
+        assert_search(&tree, 29, &["25-27"]);
+    }
+
+    #[test]
+    fn test_interval_tree_nested() {
+        let mut tree: IntervalTree<MockItem> = IntervalTree::default();
+
+        // Items containing other items
+        tree.insert(Arc::new(MockItem::new(31, 39)));
+        tree.insert(Arc::new(MockItem::new(32, 34)));
+        tree.insert(Arc::new(MockItem::new(33, 35)));
+        tree.insert(Arc::new(MockItem::new(30, 40)));
+
+        assert_search(&tree, 30, &["30-40"]);
+        assert_search(&tree, 31, &["30-40", "31-39"]);
+        assert_search(&tree, 32, &["30-40", "32-34", "31-39"]);
+        assert_search(&tree, 33, &["30-40", "32-34", "33-35", "31-39"]);
+        assert_search(&tree, 34, &["30-40", "33-35", "31-39"]);
+        assert_search(&tree, 35, &["30-40", "31-39"]);
+        assert_search(&tree, 36, &["30-40", "31-39"]);
+        assert_search(&tree, 37, &["30-40", "31-39"]);
+        assert_search(&tree, 38, &["30-40", "31-39"]);
+        assert_search(&tree, 39, &["30-40"]);
+        assert_search(&tree, 40, &["30-40"]);
+        assert_search(&tree, 41, &["30-40"]);
+    }
+
+    #[test]
+    fn test_interval_tree_duplicates() {
+        let mut tree: IntervalTree<MockItem> = IntervalTree::default();
+
+        // Duplicate keys
+        let item_a = Arc::new(MockItem::new_str(55, 56, "a"));
+        tree.insert(Arc::clone(&item_a));
+        let item_b = Arc::new(MockItem::new_str(55, 56, "b"));
+        tree.insert(Arc::clone(&item_b));
+        let item_c = Arc::new(MockItem::new_str(55, 56, "c"));
+        tree.insert(Arc::clone(&item_c));
+        let item_d = Arc::new(MockItem::new_str(54, 56, "d"));
+        tree.insert(Arc::clone(&item_d));
+        let item_e = Arc::new(MockItem::new_str(55, 57, "e"));
+        tree.insert(Arc::clone(&item_e));
+
+        dump_tree(&tree);
+
+        assert_search(
+            &tree,
+            55,
+            &["55-56: a", "55-56: b", "55-56: c", "54-56: d", "55-57: e"],
+        );
+        tree.remove(&item_b);
+        dump_tree(&tree);
+
+        assert_contents(&tree, &["54-56: d", "55-56: a", "55-56: c", "55-57: e"]);
+
+        tree.remove(&item_d);
+        dump_tree(&tree);
+        assert_contents(&tree, &["55-56: a", "55-56: c", "55-57: e"]);
+    }
+
+    #[test]
+    #[should_panic]
+    fn test_interval_tree_insert_twice() {
+        let mut tree: IntervalTree<MockItem> = IntervalTree::default();
+
+        // Inserting the same item twice is not cool
+        let item = Arc::new(MockItem::new(1, 2));
+        tree.insert(Arc::clone(&item));
+        tree.insert(Arc::clone(&item)); // fails assertion
+    }
+}

pageserver/src/layered_repository/layer_map.rs

@@ -1,67 +1,66 @@
 //!
-//! The layer map tracks what layers exist for all the relations in a timeline.
+//! The layer map tracks what layers exist for all the relishes in a timeline.
 //!
-//! When the timeline is first accessed, the server lists of all snapshot files
+//! When the timeline is first accessed, the server lists of all layer files
 //! in the timelines/<timelineid> directory, and populates this map with
-//! SnapshotLayers corresponding to each file. When new WAL is received,
-//! we create InMemoryLayers to hold the incoming records. Now and then,
-//! in the checkpoint() function, the in-memory layers are frozen, forming
-//! new snapshot layers and corresponding files are written to disk.
+//! ImageLayer and DeltaLayer structs corresponding to each file. When new WAL
+//! is received, we create InMemoryLayers to hold the incoming records. Now and
+//! then, in the checkpoint() function, the in-memory layers are frozen, forming
+//! new image and delta layers and corresponding files are written to disk.
 //!
 
+use crate::layered_repository::interval_tree::{IntervalItem, IntervalIter, IntervalTree};
 use crate::layered_repository::storage_layer::{Layer, SegmentTag};
-use crate::layered_repository::{InMemoryLayer, SnapshotLayer};
+use crate::layered_repository::InMemoryLayer;
 use crate::relish::*;
 use anyhow::Result;
-use log::*;
-use std::collections::HashSet;
-use std::collections::{BTreeMap, HashMap};
-use std::ops::Bound::Included;
+use lazy_static::lazy_static;
+use std::cmp::Ordering;
+use std::collections::{BinaryHeap, HashMap};
 use std::sync::Arc;
+use zenith_metrics::{register_int_gauge, IntGauge};
 use zenith_utils::lsn::Lsn;
 
-///
-/// LayerMap tracks what layers exist or a timeline. The last layer that is
-/// open for writes is always an InMemoryLayer, and is tracked separately
-/// because there can be only one for each segment. The older layers,
-/// stored on disk, are kept in a BTreeMap keyed by the layer's start LSN.
-///
-pub struct LayerMap {
-    segs: HashMap<SegmentTag, SegEntry>,
+use super::global_layer_map::{LayerId, GLOBAL_LAYER_MAP};
+
+lazy_static! {
+    static ref NUM_INMEMORY_LAYERS: IntGauge =
+        register_int_gauge!("pageserver_inmemory_layers", "Number of layers in memory")
+            .expect("failed to define a metric");
+    static ref NUM_ONDISK_LAYERS: IntGauge =
+        register_int_gauge!("pageserver_ondisk_layers", "Number of layers on-disk")
+            .expect("failed to define a metric");
 }
 
-struct SegEntry {
-    pub open: Option<Arc<InMemoryLayer>>,
-    pub historic: BTreeMap<Lsn, Arc<SnapshotLayer>>,
+///
+/// LayerMap tracks what layers exist on a timeline.
+///
+#[derive(Default)]
+pub struct LayerMap {
+    /// All the layers keyed by segment tag
+    segs: HashMap<SegmentTag, SegEntry>,
+
+    /// All in-memory layers, ordered by 'oldest_pending_lsn' and generation
+    /// of each layer. This allows easy access to the in-memory layer that
+    /// contains the oldest WAL record.
+    open_layers: BinaryHeap<OpenLayerEntry>,
+
+    /// Generation number, used to distinguish newly inserted entries in the
+    /// binary heap from older entries during checkpoint.
+    current_generation: u64,
 }
 
 impl LayerMap {
     ///
-    /// Look up using the given segment tag and LSN. This differs from a plain
-    /// key-value lookup in that if there is any layer that covers the
+    /// Look up a layer using the given segment tag and LSN. This differs from a
+    /// plain key-value lookup in that if there is any layer that covers the
     /// given LSN, or precedes the given LSN, it is returned. In other words,
     /// you don't need to know the exact start LSN of the layer.
     ///
     pub fn get(&self, tag: &SegmentTag, lsn: Lsn) -> Option<Arc<dyn Layer>> {
         let segentry = self.segs.get(tag)?;
 
-        if let Some(open) = &segentry.open {
-            if open.get_start_lsn() <= lsn {
-                let x: Arc<dyn Layer> = Arc::clone(&open) as _;
-                return Some(x);
-            }
-        }
-
-        if let Some((_k, v)) = segentry
-            .historic
-            .range((Included(Lsn(0)), Included(lsn)))
-            .next_back()
-        {
-            let x: Arc<dyn Layer> = Arc::clone(&v) as _;
-            Some(x)
-        } else {
-            None
-        }
+        segentry.get(lsn)
     }
 
     ///
@@ -71,52 +70,76 @@ impl LayerMap {
     pub fn get_open(&self, tag: &SegmentTag) -> Option<Arc<InMemoryLayer>> {
         let segentry = self.segs.get(tag)?;
 
-        if let Some(open) = &segentry.open {
-            Some(Arc::clone(open))
-        } else {
-            None
-        }
+        segentry
+            .open_layer_id
+            .and_then(|layer_id| GLOBAL_LAYER_MAP.read().unwrap().get(&layer_id))
     }
 
     ///
     /// Insert an open in-memory layer
     ///
     pub fn insert_open(&mut self, layer: Arc<InMemoryLayer>) {
-        let tag = layer.get_seg_tag();
+        let segentry = self.segs.entry(layer.get_seg_tag()).or_default();
 
-        if let Some(segentry) = self.segs.get_mut(&tag) {
-            if let Some(_old) = &segentry.open {
-                // FIXME: shouldn't exist, but check
+        let layer_id = segentry.update_open(Arc::clone(&layer));
+
+        let oldest_pending_lsn = layer.get_oldest_pending_lsn();
+
+        // After a crash and restart, 'oldest_pending_lsn' of the oldest in-memory
+        // layer becomes the WAL streaming starting point, so it better not point
+        // in the middle of a WAL record.
+        assert!(oldest_pending_lsn.is_aligned());
+
+        // Also add it to the binary heap
+        let open_layer_entry = OpenLayerEntry {
+            oldest_pending_lsn: layer.get_oldest_pending_lsn(),
+            layer_id,
+            generation: self.current_generation,
+        };
+        self.open_layers.push(open_layer_entry);
+
+        NUM_INMEMORY_LAYERS.inc();
+    }
+
+    /// Remove an open in-memory layer
+    pub fn remove_open(&mut self, layer_id: LayerId) {
+        // Note: we don't try to remove the entry from the binary heap.
+        // It will be removed lazily by peek_oldest_open() when it's made it to
+        // the top of the heap.
+
+        let layer_opt = {
+            let mut global_map = GLOBAL_LAYER_MAP.write().unwrap();
+            let layer_opt = global_map.get(&layer_id);
+            global_map.remove(&layer_id);
+            // TODO it's bad that a ref can still exist after being evicted from cache
+            layer_opt
+        };
+
+        if let Some(layer) = layer_opt {
+            let mut segentry = self.segs.get_mut(&layer.get_seg_tag()).unwrap();
+
+            if segentry.open_layer_id == Some(layer_id) {
+                // Also remove it from the SegEntry of this segment
+                segentry.open_layer_id = None;
+            } else {
+                // We could have already updated segentry.open for
+                // dropped (non-writeable) layer. This is fine.
+                assert!(!layer.is_writeable());
+                assert!(layer.is_dropped());
             }
-            segentry.open = Some(layer);
-        } else {
-            let segentry = SegEntry {
-                open: Some(layer),
-                historic: BTreeMap::new(),
-            };
-            self.segs.insert(tag, segentry);
+
+            NUM_INMEMORY_LAYERS.dec();
         }
     }
 
     ///
     /// Insert an on-disk layer
     ///
-    pub fn insert_historic(&mut self, layer: Arc<SnapshotLayer>) {
-        let tag = layer.get_seg_tag();
-        let start_lsn = layer.get_start_lsn();
+    pub fn insert_historic(&mut self, layer: Arc<dyn Layer>) {
+        let segentry = self.segs.entry(layer.get_seg_tag()).or_default();
+        segentry.insert_historic(layer);
 
-        if let Some(segentry) = self.segs.get_mut(&tag) {
-            segentry.historic.insert(start_lsn, layer);
-        } else {
-            let mut historic = BTreeMap::new();
-            historic.insert(start_lsn, layer);
-
-            let segentry = SegEntry {
-                open: None,
-                historic,
-            };
-            self.segs.insert(tag, segentry);
-        }
+        NUM_ONDISK_LAYERS.inc();
     }
 
     ///
@@ -124,154 +147,250 @@ impl LayerMap {
     ///
     /// This should be called when the corresponding file on disk has been deleted.
     ///
-    pub fn remove_historic(&mut self, layer: &SnapshotLayer) {
+    pub fn remove_historic(&mut self, layer: Arc<dyn Layer>) {
         let tag = layer.get_seg_tag();
-        let start_lsn = layer.get_start_lsn();
 
         if let Some(segentry) = self.segs.get_mut(&tag) {
-            segentry.historic.remove(&start_lsn);
+            segentry.historic.remove(&layer);
         }
+        NUM_ONDISK_LAYERS.dec();
     }
 
-    pub fn list_rels(&self, spcnode: u32, dbnode: u32) -> Result<HashSet<RelTag>> {
-        let mut rels: HashSet<RelTag> = HashSet::new();
+    // List relations along with a flag that marks if they exist at the given lsn.
+    // spcnode 0 and dbnode 0 have special meanings and mean all tabespaces/databases.
+    // Pass Tag if we're only interested in some relations.
+    pub fn list_relishes(&self, tag: Option<RelTag>, lsn: Lsn) -> Result<HashMap<RelishTag, bool>> {
+        let mut rels: HashMap<RelishTag, bool> = HashMap::new();
 
-        for (seg, _entry) in self.segs.iter() {
-            if let RelishTag::Relation(reltag) = seg.rel {
-                // FIXME: skip if it was dropped before the requested LSN. But there is no
-                // LSN argument
-
-                if (spcnode == 0 || reltag.spcnode == spcnode)
-                    && (dbnode == 0 || reltag.dbnode == dbnode)
-                {
-                    rels.insert(reltag);
+        for (seg, segentry) in self.segs.iter() {
+            match seg.rel {
+                RelishTag::Relation(reltag) => {
+                    if let Some(request_rel) = tag {
+                        if (request_rel.spcnode == 0 || reltag.spcnode == request_rel.spcnode)
+                            && (request_rel.dbnode == 0 || reltag.dbnode == request_rel.dbnode)
+                        {
+                            if let Some(exists) = segentry.exists_at_lsn(lsn)? {
+                                rels.insert(seg.rel, exists);
+                            }
+                        }
+                    }
+                }
+                _ => {
+                    if tag == None {
+                        if let Some(exists) = segentry.exists_at_lsn(lsn)? {
+                            rels.insert(seg.rel, exists);
+                        }
+                    }
                 }
             }
         }
         Ok(rels)
     }
 
-    pub fn list_nonrels(&self, _lsn: Lsn) -> Result<HashSet<RelishTag>> {
-        let mut rels: HashSet<RelishTag> = HashSet::new();
-
-        // Scan the timeline directory to get all rels in this timeline.
-        for (seg, _entry) in self.segs.iter() {
-            // FIXME: skip if it was dropped before the requested LSN.
-
-            if let RelishTag::Relation(_) = seg.rel {
-            } else {
-                rels.insert(seg.rel);
-            }
-        }
-        Ok(rels)
-    }
-
-    /// Is there a newer layer for given segment?
-    pub fn newer_layer_exists(&self, seg: SegmentTag, lsn: Lsn) -> bool {
+    /// Is there a newer image layer for given segment?
+    ///
+    /// This is used for garbage collection, to determine if an old layer can
+    /// be deleted.
+    pub fn newer_image_layer_exists(&self, seg: SegmentTag, lsn: Lsn) -> bool {
         if let Some(segentry) = self.segs.get(&seg) {
-            if let Some(_open) = &segentry.open {
-                return true;
-            }
-
-            for (newer_lsn, layer) in segentry
-                .historic
-                .range((Included(lsn), Included(Lsn(u64::MAX))))
-            {
-                if layer.get_end_lsn() > lsn {
-                    trace!(
-                        "found later layer for {}, {} {}-{}",
-                        seg,
-                        lsn,
-                        newer_lsn,
-                        layer.get_end_lsn()
-                    );
-                    return true;
-                } else {
-                    trace!("found singleton layer for {}, {} {}", seg, lsn, newer_lsn);
-                    continue;
-                }
-            }
+            segentry.newer_image_layer_exists(lsn)
+        } else {
+            false
         }
-        trace!("no later layer found for {}, {}", seg, lsn);
-        false
     }
 
-    pub fn iter_open_layers(&mut self) -> OpenLayerIter {
-        OpenLayerIter {
-            last: None,
-            segiter: self.segs.iter_mut(),
+    /// Is there any layer for given segment that is alive at the lsn?
+    ///
+    /// This is a public wrapper for SegEntry fucntion,
+    /// used for garbage collection, to determine if some alive layer
+    /// exists at the lsn. If so, we shouldn't delete a newer dropped layer
+    /// to avoid incorrectly making it visible.
+    pub fn layer_exists_at_lsn(&self, seg: SegmentTag, lsn: Lsn) -> Result<bool> {
+        Ok(if let Some(segentry) = self.segs.get(&seg) {
+            segentry.exists_at_lsn(lsn)?.unwrap_or(false)
+        } else {
+            false
+        })
+    }
+
+    /// Return the oldest in-memory layer, along with its generation number.
+    pub fn peek_oldest_open(&mut self) -> Option<(LayerId, Arc<InMemoryLayer>, u64)> {
+        let global_map = GLOBAL_LAYER_MAP.read().unwrap();
+
+        while let Some(oldest_entry) = self.open_layers.peek() {
+            if let Some(layer) = global_map.get(&oldest_entry.layer_id) {
+                return Some((oldest_entry.layer_id, layer, oldest_entry.generation));
+            } else {
+                self.open_layers.pop();
+            }
         }
+        None
+    }
+
+    /// Increment the generation number used to stamp open in-memory layers. Layers
+    /// added with `insert_open` after this call will be associated with the new
+    /// generation. Returns the new generation number.
+    pub fn increment_generation(&mut self) -> u64 {
+        self.current_generation += 1;
+        self.current_generation
     }
 
     pub fn iter_historic_layers(&self) -> HistoricLayerIter {
         HistoricLayerIter {
-            segiter: self.segs.iter(),
+            seg_iter: self.segs.iter(),
             iter: None,
         }
     }
-}
 
-impl Default for LayerMap {
-    fn default() -> Self {
-        LayerMap {
-            segs: HashMap::new(),
-        }
-    }
-}
+    /// debugging function to print out the contents of the layer map
+    #[allow(unused)]
+    pub fn dump(&self) -> Result<()> {
+        println!("Begin dump LayerMap");
+        for (seg, segentry) in self.segs.iter() {
+            if let Some(open) = &segentry.open_layer_id {
+                if let Some(layer) = GLOBAL_LAYER_MAP.read().unwrap().get(open) {
+                    layer.dump()?;
+                } else {
+                    println!("layer not found in global map");
+                }
+            }
 
-pub struct OpenLayerIter<'a> {
-    last: Option<&'a mut SegEntry>,
-
-    segiter: std::collections::hash_map::IterMut<'a, SegmentTag, SegEntry>,
-}
-
-impl<'a> OpenLayerIter<'a> {
-    pub fn replace(&mut self, replacement: Option<Arc<InMemoryLayer>>) {
-        let segentry = self.last.as_mut().unwrap();
-        segentry.open = replacement;
-    }
-
-    pub fn insert_historic(&mut self, new_layer: Arc<SnapshotLayer>) {
-        let start_lsn = new_layer.get_start_lsn();
-
-        let segentry = self.last.as_mut().unwrap();
-        segentry.historic.insert(start_lsn, new_layer);
-    }
-}
-
-impl<'a> Iterator for OpenLayerIter<'a> {
-    type Item = Arc<InMemoryLayer>;
-
-    fn next(&mut self) -> std::option::Option<<Self as std::iter::Iterator>::Item> {
-        while let Some((_seg, entry)) = self.segiter.next() {
-            if let Some(open) = &entry.open {
-                let op = Arc::clone(&open);
-                self.last = Some(entry);
-                return Some(op);
+            for layer in segentry.historic.iter() {
+                layer.dump()?;
             }
         }
-        self.last = None;
-        None
+        println!("End dump LayerMap");
+        Ok(())
     }
 }
 
+impl IntervalItem for dyn Layer {
+    type Key = Lsn;
+
+    fn start_key(&self) -> Lsn {
+        self.get_start_lsn()
+    }
+    fn end_key(&self) -> Lsn {
+        self.get_end_lsn()
+    }
+}
+
+///
+/// Per-segment entry in the LayerMap::segs hash map. Holds all the layers
+/// associated with the segment.
+///
+/// The last layer that is open for writes is always an InMemoryLayer,
+/// and is kept in a separate field, because there can be only one for
+/// each segment. The older layers, stored on disk, are kept in an
+/// IntervalTree.
+#[derive(Default)]
+struct SegEntry {
+    open_layer_id: Option<LayerId>,
+    historic: IntervalTree<dyn Layer>,
+}
+
+impl SegEntry {
+    /// Does the segment exist at given LSN?
+    /// Return None if object is not found in this SegEntry.
+    fn exists_at_lsn(&self, lsn: Lsn) -> Result<Option<bool>> {
+        if let Some(layer) = self.get(lsn) {
+            Ok(Some(layer.get_seg_exists(lsn)?))
+        } else {
+            Ok(None)
+        }
+    }
+
+    pub fn get(&self, lsn: Lsn) -> Option<Arc<dyn Layer>> {
+        if let Some(open_layer_id) = &self.open_layer_id {
+            let open_layer = GLOBAL_LAYER_MAP.read().unwrap().get(open_layer_id)?;
+            if open_layer.get_start_lsn() <= lsn {
+                return Some(open_layer);
+            }
+        }
+
+        self.historic.search(lsn)
+    }
+
+    pub fn newer_image_layer_exists(&self, lsn: Lsn) -> bool {
+        // We only check on-disk layers, because
+        // in-memory layers are not durable
+
+        self.historic
+            .iter_newer(lsn)
+            .any(|layer| !layer.is_incremental())
+    }
+
+    // Set new open layer for a SegEntry.
+    // It's ok to rewrite previous open layer,
+    // but only if it is not writeable anymore.
+    pub fn update_open(&mut self, layer: Arc<InMemoryLayer>) -> LayerId {
+        if let Some(prev_open_layer_id) = &self.open_layer_id {
+            if let Some(prev_open_layer) = GLOBAL_LAYER_MAP.read().unwrap().get(prev_open_layer_id)
+            {
+                assert!(!prev_open_layer.is_writeable());
+            }
+        }
+        let open_layer_id = GLOBAL_LAYER_MAP.write().unwrap().insert(layer);
+        self.open_layer_id = Some(open_layer_id);
+        open_layer_id
+    }
+
+    pub fn insert_historic(&mut self, layer: Arc<dyn Layer>) {
+        self.historic.insert(layer);
+    }
+}
+
+/// Entry held in LayerMap::open_layers, with boilerplate comparison routines
+/// to implement a min-heap ordered by 'oldest_pending_lsn' and 'generation'
+///
+/// The generation number associated with each entry can be used to distinguish
+/// recently-added entries (i.e after last call to increment_generation()) from older
+/// entries with the same 'oldest_pending_lsn'.
+struct OpenLayerEntry {
+    oldest_pending_lsn: Lsn, // copy of layer.get_oldest_pending_lsn()
+    generation: u64,
+    layer_id: LayerId,
+}
+impl Ord for OpenLayerEntry {
+    fn cmp(&self, other: &Self) -> Ordering {
+        // BinaryHeap is a max-heap, and we want a min-heap. Reverse the ordering here
+        // to get that. Entries with identical oldest_pending_lsn are ordered by generation
+        other
+            .oldest_pending_lsn
+            .cmp(&self.oldest_pending_lsn)
+            .then_with(|| other.generation.cmp(&self.generation))
+    }
+}
+impl PartialOrd for OpenLayerEntry {
+    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+        Some(self.cmp(other))
+    }
+}
+impl PartialEq for OpenLayerEntry {
+    fn eq(&self, other: &Self) -> bool {
+        self.cmp(other) == Ordering::Equal
+    }
+}
+impl Eq for OpenLayerEntry {}
+
+/// Iterator returned by LayerMap::iter_historic_layers()
 pub struct HistoricLayerIter<'a> {
-    segiter: std::collections::hash_map::Iter<'a, SegmentTag, SegEntry>,
-    iter: Option<std::collections::btree_map::Iter<'a, Lsn, Arc<SnapshotLayer>>>,
+    seg_iter: std::collections::hash_map::Iter<'a, SegmentTag, SegEntry>,
+    iter: Option<IntervalIter<'a, dyn Layer>>,
 }
 
 impl<'a> Iterator for HistoricLayerIter<'a> {
-    type Item = Arc<SnapshotLayer>;
+    type Item = Arc<dyn Layer>;
 
     fn next(&mut self) -> std::option::Option<<Self as std::iter::Iterator>::Item> {
         loop {
             if let Some(x) = &mut self.iter {
                 if let Some(x) = x.next() {
-                    return Some(Arc::clone(&*x.1));
+                    return Some(Arc::clone(&x));
                 }
             }
-            if let Some(seg) = self.segiter.next() {
-                self.iter = Some(seg.1.historic.iter());
+            if let Some((_tag, segentry)) = self.seg_iter.next() {
+                self.iter = Some(segentry.historic.iter());
                 continue;
             } else {
                 return None;
@@ -279,3 +398,78 @@ impl<'a> Iterator for HistoricLayerIter<'a> {
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::PageServerConf;
+    use std::str::FromStr;
+    use zenith_utils::zid::{ZTenantId, ZTimelineId};
+
+    /// Arbitrary relation tag, for testing.
+    const TESTREL_A: RelishTag = RelishTag::Relation(RelTag {
+        spcnode: 0,
+        dbnode: 111,
+        relnode: 1000,
+        forknum: 0,
+    });
+
+    /// Construct a dummy InMemoryLayer for testing
+    fn dummy_inmem_layer(
+        conf: &'static PageServerConf,
+        segno: u32,
+        start_lsn: Lsn,
+        oldest_pending_lsn: Lsn,
+    ) -> Arc<InMemoryLayer> {
+        Arc::new(
+            InMemoryLayer::create(
+                conf,
+                ZTimelineId::from_str("00000000000000000000000000000000").unwrap(),
+                ZTenantId::from_str("00000000000000000000000000000000").unwrap(),
+                SegmentTag {
+                    rel: TESTREL_A,
+                    segno,
+                },
+                start_lsn,
+                oldest_pending_lsn,
+            )
+            .unwrap(),
+        )
+    }
+
+    #[test]
+    fn test_open_layers() -> Result<()> {
+        let conf = PageServerConf::dummy_conf(PageServerConf::test_repo_dir("dummy_inmem_layer"));
+        let conf = Box::leak(Box::new(conf));
+
+        let mut layers = LayerMap::default();
+
+        let gen1 = layers.increment_generation();
+        layers.insert_open(dummy_inmem_layer(conf, 0, Lsn(0x100), Lsn(0x100)));
+        layers.insert_open(dummy_inmem_layer(conf, 1, Lsn(0x100), Lsn(0x200)));
+        layers.insert_open(dummy_inmem_layer(conf, 2, Lsn(0x100), Lsn(0x120)));
+        layers.insert_open(dummy_inmem_layer(conf, 3, Lsn(0x100), Lsn(0x110)));
+
+        let gen2 = layers.increment_generation();
+        layers.insert_open(dummy_inmem_layer(conf, 4, Lsn(0x100), Lsn(0x110)));
+        layers.insert_open(dummy_inmem_layer(conf, 5, Lsn(0x100), Lsn(0x100)));
+
+        // A helper function (closure) to pop the next oldest open entry from the layer map,
+        // and assert that it is what we'd expect
+        let mut assert_pop_layer = |expected_segno: u32, expected_generation: u64| {
+            let (layer_id, l, generation) = layers.peek_oldest_open().unwrap();
+            assert!(l.get_seg_tag().segno == expected_segno);
+            assert!(generation == expected_generation);
+            layers.remove_open(layer_id);
+        };
+
+        assert_pop_layer(0, gen1); // 0x100
+        assert_pop_layer(5, gen2); // 0x100
+        assert_pop_layer(3, gen1); // 0x110
+        assert_pop_layer(4, gen2); // 0x110
+        assert_pop_layer(2, gen1); // 0x120
+        assert_pop_layer(1, gen1); // 0x200
+
+        Ok(())
+    }
+}

pageserver/src/layered_repository/metadata.rs

@@ -0,0 +1,202 @@
+//! Every image of a certain timeline from [`crate::layered_repository::LayeredRepository`]
+//! has a metadata that needs to be stored persistently.
+//!
+//! Later, the file gets is used in [`crate::remote_storage::storage_sync`] as a part of
+//! external storage import and export operations.
+//!
+//! The module contains all structs and related helper methods related to timeline metadata.
+
+use std::{convert::TryInto, path::PathBuf};
+
+use anyhow::ensure;
+use zenith_utils::{
+    bin_ser::BeSer,
+    lsn::Lsn,
+    zid::{ZTenantId, ZTimelineId},
+};
+
+use crate::{
+    layered_repository::{METADATA_CHECKSUM_SIZE, METADATA_MAX_DATA_SIZE, METADATA_MAX_SAFE_SIZE},
+    PageServerConf,
+};
+
+/// The name of the metadata file pageserver creates per timeline.
+pub const METADATA_FILE_NAME: &str = "metadata";
+
+/// Metadata stored on disk for each timeline
+///
+/// The fields correspond to the values we hold in memory, in LayeredTimeline.
+#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord)]
+pub struct TimelineMetadata {
+    disk_consistent_lsn: Lsn,
+    // This is only set if we know it. We track it in memory when the page
+    // server is running, but we only track the value corresponding to
+    // 'last_record_lsn', not 'disk_consistent_lsn' which can lag behind by a
+    // lot. We only store it in the metadata file when we flush *all* the
+    // in-memory data so that 'last_record_lsn' is the same as
+    // 'disk_consistent_lsn'.  That's OK, because after page server restart, as
+    // soon as we reprocess at least one record, we will have a valid
+    // 'prev_record_lsn' value in memory again. This is only really needed when
+    // doing a clean shutdown, so that there is no more WAL beyond
+    // 'disk_consistent_lsn'
+    prev_record_lsn: Option<Lsn>,
+    ancestor_timeline: Option<ZTimelineId>,
+    ancestor_lsn: Lsn,
+}
+
+/// Points to a place in pageserver's local directory,
+/// where certain timeline's metadata file should be located.
+pub fn metadata_path(
+    conf: &'static PageServerConf,
+    timelineid: ZTimelineId,
+    tenantid: ZTenantId,
+) -> PathBuf {
+    conf.timeline_path(&timelineid, &tenantid)
+        .join(METADATA_FILE_NAME)
+}
+
+impl TimelineMetadata {
+    pub fn new(
+        disk_consistent_lsn: Lsn,
+        prev_record_lsn: Option<Lsn>,
+        ancestor_timeline: Option<ZTimelineId>,
+        ancestor_lsn: Lsn,
+    ) -> Self {
+        Self {
+            disk_consistent_lsn,
+            prev_record_lsn,
+            ancestor_timeline,
+            ancestor_lsn,
+        }
+    }
+
+    pub fn from_bytes(metadata_bytes: &[u8]) -> anyhow::Result<Self> {
+        ensure!(
+            metadata_bytes.len() == METADATA_MAX_SAFE_SIZE,
+            "metadata bytes size is wrong"
+        );
+
+        let data = &metadata_bytes[..METADATA_MAX_DATA_SIZE];
+        let calculated_checksum = crc32c::crc32c(data);
+
+        let checksum_bytes: &[u8; METADATA_CHECKSUM_SIZE] =
+            metadata_bytes[METADATA_MAX_DATA_SIZE..].try_into()?;
+        let expected_checksum = u32::from_le_bytes(*checksum_bytes);
+        ensure!(
+            calculated_checksum == expected_checksum,
+            "metadata checksum mismatch"
+        );
+
+        let data = TimelineMetadata::from(serialize::DeTimelineMetadata::des_prefix(data)?);
+        assert!(data.disk_consistent_lsn.is_aligned());
+
+        Ok(data)
+    }
+
+    pub fn to_bytes(&self) -> anyhow::Result<Vec<u8>> {
+        let serializeable_metadata = serialize::SeTimelineMetadata::from(self);
+        let mut metadata_bytes = serialize::SeTimelineMetadata::ser(&serializeable_metadata)?;
+        assert!(metadata_bytes.len() <= METADATA_MAX_DATA_SIZE);
+        metadata_bytes.resize(METADATA_MAX_SAFE_SIZE, 0u8);
+
+        let checksum = crc32c::crc32c(&metadata_bytes[..METADATA_MAX_DATA_SIZE]);
+        metadata_bytes[METADATA_MAX_DATA_SIZE..].copy_from_slice(&u32::to_le_bytes(checksum));
+        Ok(metadata_bytes)
+    }
+
+    /// [`Lsn`] that corresponds to the corresponding timeline directory
+    /// contents, stored locally in the pageserver workdir.
+    pub fn disk_consistent_lsn(&self) -> Lsn {
+        self.disk_consistent_lsn
+    }
+
+    pub fn prev_record_lsn(&self) -> Option<Lsn> {
+        self.prev_record_lsn
+    }
+
+    pub fn ancestor_timeline(&self) -> Option<ZTimelineId> {
+        self.ancestor_timeline
+    }
+
+    pub fn ancestor_lsn(&self) -> Lsn {
+        self.ancestor_lsn
+    }
+}
+
+/// This module is for direct conversion of metadata to bytes and back.
+/// For a certain metadata, besides the conversion a few verification steps has to
+/// be done, so all serde derives are hidden from the user, to avoid accidental
+/// verification-less metadata creation.
+mod serialize {
+    use serde::{Deserialize, Serialize};
+    use zenith_utils::{lsn::Lsn, zid::ZTimelineId};
+
+    use super::TimelineMetadata;
+
+    #[derive(Serialize)]
+    pub(super) struct SeTimelineMetadata<'a> {
+        disk_consistent_lsn: &'a Lsn,
+        prev_record_lsn: &'a Option<Lsn>,
+        ancestor_timeline: &'a Option<ZTimelineId>,
+        ancestor_lsn: &'a Lsn,
+    }
+
+    impl<'a> From<&'a TimelineMetadata> for SeTimelineMetadata<'a> {
+        fn from(other: &'a TimelineMetadata) -> Self {
+            Self {
+                disk_consistent_lsn: &other.disk_consistent_lsn,
+                prev_record_lsn: &other.prev_record_lsn,
+                ancestor_timeline: &other.ancestor_timeline,
+                ancestor_lsn: &other.ancestor_lsn,
+            }
+        }
+    }
+
+    #[derive(Deserialize)]
+    pub(super) struct DeTimelineMetadata {
+        disk_consistent_lsn: Lsn,
+        prev_record_lsn: Option<Lsn>,
+        ancestor_timeline: Option<ZTimelineId>,
+        ancestor_lsn: Lsn,
+    }
+
+    impl From<DeTimelineMetadata> for TimelineMetadata {
+        fn from(other: DeTimelineMetadata) -> Self {
+            Self {
+                disk_consistent_lsn: other.disk_consistent_lsn,
+                prev_record_lsn: other.prev_record_lsn,
+                ancestor_timeline: other.ancestor_timeline,
+                ancestor_lsn: other.ancestor_lsn,
+            }
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::repository::repo_harness::TIMELINE_ID;
+
+    use super::*;
+
+    #[test]
+    fn metadata_serializes_correctly() {
+        let original_metadata = TimelineMetadata {
+            disk_consistent_lsn: Lsn(0x200),
+            prev_record_lsn: Some(Lsn(0x100)),
+            ancestor_timeline: Some(TIMELINE_ID),
+            ancestor_lsn: Lsn(0),
+        };
+
+        let metadata_bytes = original_metadata
+            .to_bytes()
+            .expect("Should serialize correct metadata to bytes");
+
+        let deserialized_metadata = TimelineMetadata::from_bytes(&metadata_bytes)
+            .expect("Should deserialize its own bytes");
+
+        assert_eq!(
+            deserialized_metadata, original_metadata,
+            "Metadata that was serialized to bytes and deserialized back should not change"
+        );
+    }
+}

pageserver/src/layered_repository/page_versions.rs

@@ -0,0 +1,174 @@
+use std::{collections::HashMap, ops::RangeBounds, slice};
+
+use anyhow::Result;
+
+use zenith_utils::chunked_buffer::{ChunkToken, ChunkedBuffer};
+use zenith_utils::{lsn::Lsn, vec_map::VecMap};
+
+use super::storage_layer::PageVersion;
+
+const EMPTY_SLICE: &[(Lsn, ChunkToken)] = &[];
+
+#[derive(Debug, Default)]
+pub struct PageVersions {
+    map: HashMap<u32, VecMap<Lsn, ChunkToken>>,
+
+    /// The PageVersion structs are stored in a serialized format in this buffer.
+    /// Each serialized PageVersion is preceded by a 'u32' length field.
+    /// The 'map' stores offsets into this buffer.
+    buffer: ChunkedBuffer,
+}
+
+impl PageVersions {
+    pub fn append_or_update_last(
+        &mut self,
+        blknum: u32,
+        lsn: Lsn,
+        page_version: PageVersion,
+    ) -> Option<ChunkToken> {
+        let token = self.buffer.write(page_version.bytes());
+
+        let map = self.map.entry(blknum).or_insert_with(VecMap::default);
+        map.append_or_update_last(lsn, token).unwrap()
+    }
+
+    /// Get all [`PageVersion`]s in a block
+    fn get_block_slice(&self, blknum: u32) -> &[(Lsn, ChunkToken)] {
+        self.map
+            .get(&blknum)
+            .map(VecMap::as_slice)
+            .unwrap_or(EMPTY_SLICE)
+    }
+
+    /// Get a range of [`PageVersions`] in a block
+    pub fn get_block_lsn_range<R: RangeBounds<Lsn>>(
+        &self,
+        blknum: u32,
+        range: R,
+    ) -> &[(Lsn, ChunkToken)] {
+        self.map
+            .get(&blknum)
+            .map(|vec_map| vec_map.slice_range(range))
+            .unwrap_or(EMPTY_SLICE)
+    }
+
+    /// Iterate through [`PageVersion`]s in (block, lsn) order.
+    /// If a [`cutoff_lsn`] is set, only show versions with `lsn < cutoff_lsn`
+    pub fn ordered_page_version_iter(&self, cutoff_lsn: Option<Lsn>) -> OrderedPageVersionIter<'_> {
+        let mut ordered_blocks: Vec<u32> = self.map.keys().cloned().collect();
+        ordered_blocks.sort_unstable();
+
+        let slice = ordered_blocks
+            .first()
+            .map(|&blknum| self.get_block_slice(blknum))
+            .unwrap_or(EMPTY_SLICE);
+
+        OrderedPageVersionIter {
+            page_versions: self,
+            ordered_blocks,
+            cur_block_idx: 0,
+            cutoff_lsn,
+            cur_slice_iter: slice.iter(),
+        }
+    }
+
+    pub fn get_page_version_bytes(&self, token: &ChunkToken) -> Vec<u8> {
+        self.buffer.read(token)
+    }
+
+    pub fn get_page_version(&self, token: &ChunkToken) -> Result<PageVersion> {
+        let buf = self.get_page_version_bytes(token).into_boxed_slice();
+        Ok(PageVersion::from_bytes(buf))
+    }
+}
+
+pub struct OrderedPageVersionIter<'a> {
+    page_versions: &'a PageVersions,
+
+    ordered_blocks: Vec<u32>,
+    cur_block_idx: usize,
+
+    cutoff_lsn: Option<Lsn>,
+
+    cur_slice_iter: slice::Iter<'a, (Lsn, ChunkToken)>,
+}
+
+impl OrderedPageVersionIter<'_> {
+    fn is_lsn_before_cutoff(&self, lsn: &Lsn) -> bool {
+        if let Some(cutoff_lsn) = self.cutoff_lsn.as_ref() {
+            lsn < cutoff_lsn
+        } else {
+            true
+        }
+    }
+}
+
+impl<'a> Iterator for OrderedPageVersionIter<'a> {
+    type Item = (u32, Lsn, &'a ChunkToken);
+
+    fn next(&mut self) -> Option<Self::Item> {
+        loop {
+            if let Some((lsn, token)) = self.cur_slice_iter.next() {
+                if self.is_lsn_before_cutoff(lsn) {
+                    let blknum = self.ordered_blocks[self.cur_block_idx];
+                    return Some((blknum, *lsn, token));
+                }
+            }
+
+            let next_block_idx = self.cur_block_idx + 1;
+            let blknum: u32 = *self.ordered_blocks.get(next_block_idx)?;
+            self.cur_block_idx = next_block_idx;
+            self.cur_slice_iter = self.page_versions.get_block_slice(blknum).iter();
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::layered_repository::storage_layer::Page;
+
+    use super::*;
+
+    #[test]
+    fn test_ordered_iter() {
+        let mut page_versions = PageVersions::default();
+        const BLOCKS: u32 = 1000;
+        const LSNS: u64 = 50;
+
+        let empty_page_version = PageVersion::Page(Page::zero_page());
+
+        for blknum in 0..BLOCKS {
+            for lsn in 0..LSNS {
+                let old = page_versions.append_or_update_last(
+                    blknum,
+                    Lsn(lsn),
+                    empty_page_version.clone(),
+                );
+                assert!(old.is_none());
+            }
+        }
+
+        let mut iter = page_versions.ordered_page_version_iter(None);
+        for blknum in 0..BLOCKS {
+            for lsn in 0..LSNS {
+                let (actual_blknum, actual_lsn, _pv) = iter.next().unwrap();
+                assert_eq!(actual_blknum, blknum);
+                assert_eq!(Lsn(lsn), actual_lsn);
+            }
+        }
+        assert!(iter.next().is_none());
+        assert!(iter.next().is_none()); // should be robust against excessive next() calls
+
+        const CUTOFF_LSN: Lsn = Lsn(30);
+        let mut iter = page_versions.ordered_page_version_iter(Some(CUTOFF_LSN));
+        for blknum in 0..BLOCKS {
+            for lsn in 0..CUTOFF_LSN.0 {
+                let (actual_blknum, actual_lsn, _pv) = iter.next().unwrap();
+                assert_eq!(actual_blknum, blknum);
+                assert_eq!(Lsn(lsn), actual_lsn);
+            }
+        }
+        assert!(iter.next().is_none());
+        assert!(iter.next().is_none()); // should be robust against excessive next() calls
+    }
+}

pageserver/src/layered_repository/snapshot_layer.rs

@@ -1,547 +0,0 @@
-//!
-//! A SnapshotLayer represents one snapshot file on disk. One file holds all page
-//! version and size information of one relation, in a range of LSN.
-//! The name "snapshot file" is a bit of a misnomer because a snapshot file doesn't
-//! contain a snapshot at a specific LSN, but rather all the page versions in a range
-//! of LSNs.
-//!
-//! Currently, a snapshot file contains full information needed to reconstruct any
-//! page version in the LSN range, without consulting any other snapshot files. When
-//! a new snapshot file is created for writing, the full contents of relation are
-//! materialized as it is at the beginning of the LSN range. That can be very expensive,
-//! we should find a way to store differential files. But this keeps the read-side
-//! of things simple. You can find the correct snapshot file based on RelishTag and
-//! timeline+LSN, and once you've located it, you have all the data you need to in that
-//! file.
-//!
-//! When a snapshot file needs to be accessed, we slurp the whole file into memory, into
-//! the SnapshotLayer struct. See load() and unload() functions.
-//!
-//! On disk, the snapshot files are stored in timelines/<timelineid> directory.
-//! Currently, there are no subdirectories, and each snapshot file is named like this:
-//!
-//!    <spcnode>_<dbnode>_<relnode>_<forknum>_<start LSN>_<end LSN>
-//!
-//! For example:
-//!
-//!    1663_13990_2609_0_000000000169C348_000000000169C349
-//!
-//! If a relation is dropped, we add a '_DROPPED' to the end of the filename to indicate that.
-//! So the above example would become:
-//!
-//!    1663_13990_2609_0_000000000169C348_000000000169C349_DROPPED
-//!
-//! The end LSN indicates when it was dropped in that case, we don't store it in the
-//! file contents in any way.
-//!
-//! A snapshot file is constructed using the 'bookfile' crate. Each file consists of two
-//! parts: the page versions and the relation sizes. They are stored as separate chapters.
-//!
-use crate::layered_repository::storage_layer::{
-    Layer, PageReconstructData, PageVersion, SegmentTag,
-};
-use crate::relish::*;
-use crate::PageServerConf;
-use crate::{ZTenantId, ZTimelineId};
-use anyhow::{bail, Result};
-use log::*;
-use std::collections::BTreeMap;
-use std::fmt;
-use std::fs;
-use std::fs::File;
-use std::io::Write;
-use std::ops::Bound::Included;
-use std::path::PathBuf;
-use std::sync::{Arc, Mutex, MutexGuard};
-
-use bookfile::{Book, BookWriter};
-
-use zenith_utils::bin_ser::BeSer;
-use zenith_utils::lsn::Lsn;
-
-// Magic constant to identify a Zenith snapshot file
-static SNAPSHOT_FILE_MAGIC: u32 = 0x5A616E01;
-
-static PAGE_VERSIONS_CHAPTER: u64 = 1;
-static REL_SIZES_CHAPTER: u64 = 2;
-
-#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Clone)]
-struct SnapshotFileName {
-    seg: SegmentTag,
-    start_lsn: Lsn,
-    end_lsn: Lsn,
-    dropped: bool,
-}
-
-impl SnapshotFileName {
-    fn from_str(fname: &str) -> Option<Self> {
-        // Split the filename into parts
-        //
-        //    <spcnode>_<dbnode>_<relnode>_<forknum>_<seg>_<start LSN>_<end LSN>
-        //
-        // or if it was dropped:
-        //
-        //    <spcnode>_<dbnode>_<relnode>_<forknum>_<seg>_<start LSN>_<end LSN>_DROPPED
-        //
-        let rel;
-        let mut parts;
-        if let Some(rest) = fname.strip_prefix("rel_") {
-            parts = rest.split('_');
-            rel = RelishTag::Relation(RelTag {
-                spcnode: parts.next()?.parse::<u32>().ok()?,
-                dbnode: parts.next()?.parse::<u32>().ok()?,
-                relnode: parts.next()?.parse::<u32>().ok()?,
-                forknum: parts.next()?.parse::<u8>().ok()?,
-            });
-        } else if let Some(rest) = fname.strip_prefix("pg_xact_") {
-            parts = rest.split('_');
-            rel = RelishTag::Slru {
-                slru: SlruKind::Clog,
-                segno: u32::from_str_radix(parts.next()?, 16).ok()?,
-            };
-        } else if let Some(rest) = fname.strip_prefix("pg_multixact_members_") {
-            parts = rest.split('_');
-            rel = RelishTag::Slru {
-                slru: SlruKind::MultiXactMembers,
-                segno: u32::from_str_radix(parts.next()?, 16).ok()?,
-            };
-        } else if let Some(rest) = fname.strip_prefix("pg_multixact_offsets_") {
-            parts = rest.split('_');
-            rel = RelishTag::Slru {
-                slru: SlruKind::MultiXactOffsets,
-                segno: u32::from_str_radix(parts.next()?, 16).ok()?,
-            };
-        } else if let Some(rest) = fname.strip_prefix("pg_filenodemap_") {
-            parts = rest.split('_');
-            rel = RelishTag::FileNodeMap {
-                spcnode: parts.next()?.parse::<u32>().ok()?,
-                dbnode: parts.next()?.parse::<u32>().ok()?,
-            };
-        } else if let Some(rest) = fname.strip_prefix("pg_twophase_") {
-            parts = rest.split('_');
-            rel = RelishTag::TwoPhase {
-                xid: parts.next()?.parse::<u32>().ok()?,
-            };
-        } else if let Some(rest) = fname.strip_prefix("pg_control_checkpoint_") {
-            parts = rest.split('_');
-            rel = RelishTag::Checkpoint;
-        } else if let Some(rest) = fname.strip_prefix("pg_control_") {
-            parts = rest.split('_');
-            rel = RelishTag::ControlFile;
-        } else {
-            return None;
-        }
-
-        let segno = parts.next()?.parse::<u32>().ok()?;
-
-        let seg = SegmentTag { rel, segno };
-
-        let start_lsn = Lsn::from_hex(parts.next()?).ok()?;
-        let end_lsn = Lsn::from_hex(parts.next()?).ok()?;
-
-        let mut dropped = false;
-        if let Some(suffix) = parts.next() {
-            if suffix == "DROPPED" {
-                dropped = true;
-            } else {
-                warn!("unrecognized filename in timeline dir: {}", fname);
-                return None;
-            }
-        }
-        if parts.next().is_some() {
-            warn!("unrecognized filename in timeline dir: {}", fname);
-            return None;
-        }
-
-        Some(SnapshotFileName {
-            seg,
-            start_lsn,
-            end_lsn,
-            dropped,
-        })
-    }
-
-    fn to_string(&self) -> String {
-        let basename = match self.seg.rel {
-            RelishTag::Relation(reltag) => format!(
-                "rel_{}_{}_{}_{}",
-                reltag.spcnode, reltag.dbnode, reltag.relnode, reltag.forknum
-            ),
-            RelishTag::Slru {
-                slru: SlruKind::Clog,
-                segno,
-            } => format!("pg_xact_{:04X}", segno),
-            RelishTag::Slru {
-                slru: SlruKind::MultiXactMembers,
-                segno,
-            } => format!("pg_multixact_members_{:04X}", segno),
-            RelishTag::Slru {
-                slru: SlruKind::MultiXactOffsets,
-                segno,
-            } => format!("pg_multixact_offsets_{:04X}", segno),
-            RelishTag::FileNodeMap { spcnode, dbnode } => {
-                format!("pg_filenodemap_{}_{}", spcnode, dbnode)
-            }
-            RelishTag::TwoPhase { xid } => format!("pg_twophase_{}", xid),
-            RelishTag::Checkpoint => format!("pg_control_checkpoint"),
-            RelishTag::ControlFile => format!("pg_control"),
-        };
-
-        format!(
-            "{}_{}_{:016X}_{:016X}{}",
-            basename,
-            self.seg.segno,
-            u64::from(self.start_lsn),
-            u64::from(self.end_lsn),
-            if self.dropped { "_DROPPED" } else { "" }
-        )
-    }
-}
-
-impl fmt::Display for SnapshotFileName {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "{}", self.to_string())
-    }
-}
-
-///
-/// SnapshotLayer is the in-memory data structure associated with an
-/// on-disk snapshot file.  We keep a SnapshotLayer in memory for each
-/// file, in the LayerMap. If a layer is in "loaded" state, we have a
-/// copy of the file in memory, in 'inner'. Otherwise the struct is
-/// just a placeholder for a file that exists on disk, and it needs to
-/// be loaded before using it in queries.
-///
-pub struct SnapshotLayer {
-    conf: &'static PageServerConf,
-    pub tenantid: ZTenantId,
-    pub timelineid: ZTimelineId,
-    pub seg: SegmentTag,
-
-    //
-    // This entry contains all the changes from 'start_lsn' to 'end_lsn'. The
-    // start is inclusive, and end is exclusive.
-    pub start_lsn: Lsn,
-    pub end_lsn: Lsn,
-
-    dropped: bool,
-
-    inner: Mutex<SnapshotLayerInner>,
-}
-
-pub struct SnapshotLayerInner {
-    /// If false, the 'page_versions' and 'relsizes' have not been
-    /// loaded into memory yet.
-    loaded: bool,
-
-    /// All versions of all pages in the file are are kept here.
-    /// Indexed by block number and LSN.
-    page_versions: BTreeMap<(u32, Lsn), PageVersion>,
-
-    /// `relsizes` tracks the size of the relation at different points in time.
-    relsizes: BTreeMap<Lsn, u32>,
-}
-
-impl Layer for SnapshotLayer {
-    fn get_timeline_id(&self) -> ZTimelineId {
-        return self.timelineid;
-    }
-
-    fn get_seg_tag(&self) -> SegmentTag {
-        return self.seg;
-    }
-
-    fn is_dropped(&self) -> bool {
-        return self.dropped;
-    }
-
-    fn get_start_lsn(&self) -> Lsn {
-        return self.start_lsn;
-    }
-
-    fn get_end_lsn(&self) -> Lsn {
-        return self.end_lsn;
-    }
-
-    /// Look up given page in the cache.
-    fn get_page_reconstruct_data(
-        &self,
-        blknum: u32,
-        lsn: Lsn,
-        reconstruct_data: &mut PageReconstructData,
-    ) -> Result<Option<Lsn>> {
-        // Scan the BTreeMap backwards, starting from the given entry.
-        let mut need_base_image_lsn: Option<Lsn> = Some(lsn);
-        {
-            let inner = self.load()?;
-            let minkey = (blknum, Lsn(0));
-            let maxkey = (blknum, lsn);
-            let mut iter = inner
-                .page_versions
-                .range((Included(&minkey), Included(&maxkey)));
-            while let Some(((_blknum, entry_lsn), entry)) = iter.next_back() {
-                if let Some(img) = &entry.page_image {
-                    reconstruct_data.page_img = Some(img.clone());
-                    need_base_image_lsn = None;
-                    break;
-                } else if let Some(rec) = &entry.record {
-                    reconstruct_data.records.push(rec.clone());
-                    if rec.will_init {
-                        // This WAL record initializes the page, so no need to go further back
-                        need_base_image_lsn = None;
-                        break;
-                    } else {
-                        need_base_image_lsn = Some(*entry_lsn);
-                    }
-                } else {
-                    // No base image, and no WAL record. Huh?
-                    bail!("no page image or WAL record for requested page");
-                }
-            }
-
-            // release lock on 'inner'
-        }
-
-        Ok(need_base_image_lsn)
-    }
-
-    /// Get size of the relation at given LSN
-    fn get_seg_size(&self, lsn: Lsn) -> Result<u32> {
-        // Scan the BTreeMap backwards, starting from the given entry.
-        let inner = self.load()?;
-        let mut iter = inner.relsizes.range((Included(&Lsn(0)), Included(&lsn)));
-
-        if let Some((_entry_lsn, entry)) = iter.next_back() {
-            let result = *entry;
-            drop(inner);
-            trace!("get_seg_size: {} at {} -> {}", self.seg, lsn, result);
-            Ok(result)
-        } else {
-            error!(
-                "No size found for {} at {} in snapshot layer {} {}-{}",
-                self.seg, lsn, self.seg, self.start_lsn, self.end_lsn
-            );
-            bail!(
-                "No size found for {} at {} in snapshot layer",
-                self.seg,
-                lsn
-            );
-        }
-    }
-
-    /// Does this segment exist at given LSN?
-    fn get_seg_exists(&self, lsn: Lsn) -> Result<bool> {
-        // Is the requested LSN after the rel was dropped?
-        if self.dropped && lsn >= self.end_lsn {
-            return Ok(false);
-        }
-
-        // Otherwise, it exists.
-        Ok(true)
-    }
-}
-
-impl SnapshotLayer {
-    fn path(&self) -> PathBuf {
-        Self::path_for(
-            self.conf,
-            self.timelineid,
-            self.tenantid,
-            &SnapshotFileName {
-                seg: self.seg,
-                start_lsn: self.start_lsn,
-                end_lsn: self.end_lsn,
-                dropped: self.dropped,
-            },
-        )
-    }
-
-    fn path_for(
-        conf: &'static PageServerConf,
-        timelineid: ZTimelineId,
-        tenantid: ZTenantId,
-        fname: &SnapshotFileName,
-    ) -> PathBuf {
-        conf.timeline_path(&timelineid, &tenantid)
-            .join(fname.to_string())
-    }
-
-    /// Create a new snapshot file, using the given btreemaps containing the page versions and
-    /// relsizes.
-    ///
-    /// This is used to write the in-memory layer to disk. The in-memory layer uses the same
-    /// data structure with two btreemaps as we do, so passing the btreemaps is currently
-    /// expedient.
-    pub fn create(
-        conf: &'static PageServerConf,
-        timelineid: ZTimelineId,
-        tenantid: ZTenantId,
-        seg: SegmentTag,
-        start_lsn: Lsn,
-        end_lsn: Lsn,
-        dropped: bool,
-        page_versions: BTreeMap<(u32, Lsn), PageVersion>,
-        relsizes: BTreeMap<Lsn, u32>,
-    ) -> Result<SnapshotLayer> {
-        let snapfile = SnapshotLayer {
-            conf: conf,
-            timelineid: timelineid,
-            tenantid: tenantid,
-            seg: seg,
-            start_lsn: start_lsn,
-            end_lsn,
-            dropped,
-            inner: Mutex::new(SnapshotLayerInner {
-                loaded: true,
-                page_versions: page_versions,
-                relsizes: relsizes,
-            }),
-        };
-        let inner = snapfile.inner.lock().unwrap();
-
-        // Write the in-memory btreemaps into a file
-        let path = snapfile.path();
-
-        // Note: This overwrites any existing file. There shouldn't be any.
-        // FIXME: throw an error instead?
-        let file = File::create(&path)?;
-        let book = BookWriter::new(file, SNAPSHOT_FILE_MAGIC)?;
-
-        // Write out page versions
-        let mut chapter = book.new_chapter(PAGE_VERSIONS_CHAPTER);
-        let buf = BTreeMap::ser(&inner.page_versions)?;
-        chapter.write_all(&buf)?;
-        let book = chapter.close()?;
-
-        // and relsizes to separate chapter
-        let mut chapter = book.new_chapter(REL_SIZES_CHAPTER);
-        let buf = BTreeMap::ser(&inner.relsizes)?;
-        chapter.write_all(&buf)?;
-        let book = chapter.close()?;
-
-        book.close()?;
-
-        trace!("saved {}", &path.display());
-
-        drop(inner);
-
-        Ok(snapfile)
-    }
-
-    ///
-    /// Load the contents of the file into memory
-    ///
-    fn load(&self) -> Result<MutexGuard<SnapshotLayerInner>> {
-        // quick exit if already loaded
-        let mut inner = self.inner.lock().unwrap();
-
-        if inner.loaded {
-            return Ok(inner);
-        }
-
-        let path = Self::path_for(
-            self.conf,
-            self.timelineid,
-            self.tenantid,
-            &SnapshotFileName {
-                seg: self.seg,
-                start_lsn: self.start_lsn,
-                end_lsn: self.end_lsn,
-                dropped: self.dropped,
-            },
-        );
-
-        let file = File::open(&path)?;
-        let book = Book::new(file)?;
-
-        let chapter = book.read_chapter(PAGE_VERSIONS_CHAPTER)?;
-        let page_versions = BTreeMap::des(&chapter)?;
-
-        let chapter = book.read_chapter(REL_SIZES_CHAPTER)?;
-        let relsizes = BTreeMap::des(&chapter)?;
-
-        debug!("loaded from {}", &path.display());
-
-        *inner = SnapshotLayerInner {
-            loaded: true,
-            page_versions,
-            relsizes,
-        };
-
-        Ok(inner)
-    }
-
-    /// Create SnapshotLayers representing all files on disk
-    ///
-    // TODO: returning an Iterator would be more idiomatic
-    pub fn list_snapshot_files(
-        conf: &'static PageServerConf,
-        timelineid: ZTimelineId,
-        tenantid: ZTenantId,
-    ) -> Result<Vec<Arc<SnapshotLayer>>> {
-        let path = conf.timeline_path(&timelineid, &tenantid);
-
-        let mut snapfiles: Vec<Arc<SnapshotLayer>> = Vec::new();
-        for direntry in fs::read_dir(path)? {
-            let fname = direntry?.file_name();
-            let fname = fname.to_str().unwrap();
-
-            if let Some(snapfilename) = SnapshotFileName::from_str(fname) {
-                let snapfile = SnapshotLayer {
-                    conf,
-                    timelineid,
-                    tenantid,
-                    seg: snapfilename.seg,
-                    start_lsn: snapfilename.start_lsn,
-                    end_lsn: snapfilename.end_lsn,
-                    dropped: snapfilename.dropped,
-                    inner: Mutex::new(SnapshotLayerInner {
-                        loaded: false,
-                        page_versions: BTreeMap::new(),
-                        relsizes: BTreeMap::new(),
-                    }),
-                };
-
-                snapfiles.push(Arc::new(snapfile));
-            }
-        }
-        return Ok(snapfiles);
-    }
-
-    pub fn delete(&self) -> Result<()> {
-        // delete underlying file
-        fs::remove_file(self.path())?;
-        Ok(())
-    }
-
-    ///
-    /// Release most of the memory used by this layer. If it's accessed again later,
-    /// it will need to be loaded back.
-    ///
-    pub fn unload(&self) -> Result<()> {
-        let mut inner = self.inner.lock().unwrap();
-        inner.page_versions = BTreeMap::new();
-        inner.relsizes = BTreeMap::new();
-        inner.loaded = false;
-        Ok(())
-    }
-
-    /// debugging function to print out the contents of the layer
-    #[allow(unused)]
-    pub fn dump(&self) -> String {
-        let mut result = format!(
-            "----- snapshot layer for {} {}-{} ----\n",
-            self.seg, self.start_lsn, self.end_lsn
-        );
-
-        let inner = self.inner.lock().unwrap();
-        for (k, v) in inner.relsizes.iter() {
-            result += &format!("{}: {}\n", k, v);
-        }
-        //for (k, v) in inner.page_versions.iter() {
-        //    result += &format!("blk {} at {}: {}/{}\n", k.0, k.1, v.page_image.is_some(), v.record.is_some());
-        //}
-
-        result
-    }
-}

pageserver/src/layered_repository/storage_layer.rs

@@ -3,12 +3,12 @@
 //!
 
 use crate::relish::RelishTag;
-use crate::repository::WALRecord;
-use crate::ZTimelineId;
+use crate::repository::{WALRecord, WAL_BIT};
+use crate::{ZTenantId, ZTimelineId};
 use anyhow::Result;
-use bytes::Bytes;
 use serde::{Deserialize, Serialize};
 use std::fmt;
+use std::path::PathBuf;
 
 use zenith_utils::lsn::Lsn;
 
@@ -19,7 +19,7 @@ pub const RELISH_SEG_SIZE: u32 = 10 * 1024 * 1024 / 8192;
 /// Each relish stored in the repository is divided into fixed-sized "segments",
 /// with 10 MB of key-space, or 1280 8k pages each.
 ///
-#[derive(Debug, PartialEq, Eq, PartialOrd, Hash, Ord, Clone, Copy)]
+#[derive(Debug, PartialEq, Eq, PartialOrd, Hash, Ord, Clone, Copy, Serialize, Deserialize)]
 pub struct SegmentTag {
     pub rel: RelishTag,
     pub segno: u32,
@@ -50,23 +50,50 @@ impl SegmentTag {
 ///
 /// A page version can be stored as a full page image, or as WAL record that needs
 /// to be applied over the previous page version to reconstruct this version.
-///
-/// It's also possible to have both a WAL record and a page image in the same
-/// PageVersion. That happens if page version is originally stored as a WAL record
-/// but it is later reconstructed by a GetPage@LSN request by performing WAL
-/// redo. The get_page_at_lsn() code will store the reconstructed pag image next to
-/// the WAL record in that case. TODO: That's pretty accidental, not the result
-/// of any grand design. If we want to keep reconstructed page versions around, we
-/// probably should have a separate buffer cache so that we could control the
-/// replacement policy globally. Or if we keep a reconstructed page image, we
-/// could throw away the WAL record.
-///
-#[derive(Debug, Clone, Serialize, Deserialize)]
-pub struct PageVersion {
-    /// an 8kb page image
-    pub page_image: Option<Bytes>,
-    /// WAL record to get from previous page version to this one.
-    pub record: Option<WALRecord>,
+#[derive(Debug, Clone)]
+pub enum PageVersion {
+    Page(Page),
+    Wal(WALRecord),
+}
+
+impl PageVersion {
+    pub fn from_bytes(bytes: Box<[u8]>) -> Self {
+        if bytes[0] & WAL_BIT != 0 {
+            Self::Wal(WALRecord::from_bytes(bytes))
+        } else {
+            Self::Page(Page(bytes))
+        }
+    }
+
+    pub fn bytes(&self) -> &[u8] {
+        match self {
+            Self::Page(page) => page.bytes(),
+            Self::Wal(wal) => wal.bytes(),
+        }
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct Page(Box<[u8]>);
+
+impl Page {
+    pub fn zero_page() -> Self {
+        // TODO optimize this
+        Self(vec![0u8; 1 + 8192].into_boxed_slice())
+    }
+    pub fn from_bytes(bytes: &[u8]) -> Self {
+        let mut buf = vec![0u8; 1 + bytes.len()];
+        buf[1..].copy_from_slice(bytes);
+        Self(buf.into_boxed_slice())
+    }
+
+    pub fn image(&self) -> &[u8] {
+        &self.0[1..]
+    }
+
+    pub fn bytes(&self) -> &[u8] {
+        &self.0
+    }
 }
 
 ///
@@ -77,52 +104,99 @@ pub struct PageVersion {
 /// 'records' contains the records to apply over the base image.
 ///
 pub struct PageReconstructData {
-    pub records: Vec<WALRecord>,
-    pub page_img: Option<Bytes>,
+    pub records: Vec<(Lsn, WALRecord)>,
+    pub page_img: Option<Page>,
+}
+
+/// Return value from Layer::get_page_reconstruct_data
+pub enum PageReconstructResult {
+    /// Got all the data needed to reconstruct the requested page
+    Complete,
+    /// This layer didn't contain all the required data, the caller should look up
+    /// the predecessor layer at the returned LSN and collect more data from there.
+    Continue(Lsn),
+    /// This layer didn't contain data needed to reconstruct the page version at
+    /// the returned LSN. This is usually considered an error, but might be OK
+    /// in some circumstances.
+    Missing(Lsn),
 }
 
 ///
-/// A Layer holds all page versions for one segment of a relish, in a range of LSNs.
-/// There are two kinds of layers, in-memory and snapshot layers. In-memory
+/// A Layer corresponds to one RELISH_SEG_SIZE slice of a relish in a range of LSNs.
+/// There are two kinds of layers, in-memory and on-disk layers. In-memory
 /// layers are used to ingest incoming WAL, and provide fast access
-/// to the recent page versions. Snaphot layers are stored on disk, and
+/// to the recent page versions. On-disk layers are stored as files on disk, and
 /// are immutable. This trait presents the common functionality of
-/// in-memory and snapshot layers.
-///
-/// Each layer contains a full snapshot of the segment at the start
-/// LSN. In addition to that, it contains WAL (or more page images)
-/// needed to recontruct any page version up to the end LSN.
+/// in-memory and on-disk layers.
 ///
 pub trait Layer: Send + Sync {
-    // These functions identify the relish segment and the LSN range
-    // that this Layer holds.
+    fn get_tenant_id(&self) -> ZTenantId;
+
+    /// Identify the timeline this relish belongs to
     fn get_timeline_id(&self) -> ZTimelineId;
+
+    /// Identify the relish segment
     fn get_seg_tag(&self) -> SegmentTag;
+
+    /// Inclusive start bound of the LSN range that this layer holds
     fn get_start_lsn(&self) -> Lsn;
+
+    /// Exclusive end bound of the LSN range that this layer holds.
+    ///
+    /// - For an open in-memory layer, this is MAX_LSN.
+    /// - For a frozen in-memory layer or a delta layer, this is a valid end bound.
+    /// - An image layer represents snapshot at one LSN, so end_lsn is always the snapshot LSN + 1
     fn get_end_lsn(&self) -> Lsn;
+
+    /// Is the segment represented by this layer dropped by PostgreSQL?
     fn is_dropped(&self) -> bool;
 
+    /// Filename used to store this layer on disk. (Even in-memory layers
+    /// implement this, to print a handy unique identifier for the layer for
+    /// log messages, even though they're never not on disk.)
+    fn filename(&self) -> PathBuf;
+
     ///
     /// Return data needed to reconstruct given page at LSN.
     ///
     /// It is up to the caller to collect more data from previous layer and
     /// perform WAL redo, if necessary.
     ///
-    /// If returns Some, the returned data is not complete. The caller needs
-    /// to continue with the returned 'lsn'.
-    ///
     /// Note that the 'blknum' is the offset of the page from the beginning
     /// of the *relish*, not the beginning of the segment. The requested
     /// 'blknum' must be covered by this segment.
+    ///
+    /// See PageReconstructResult for possible return values. The collected data
+    /// is appended to reconstruct_data; the caller should pass an empty struct
+    /// on first call. If this returns PageReconstructResult::Continue, look up
+    /// the predecessor layer and call again with the same 'reconstruct_data'
+    /// to collect more data.
     fn get_page_reconstruct_data(
         &self,
         blknum: u32,
         lsn: Lsn,
         reconstruct_data: &mut PageReconstructData,
-    ) -> Result<Option<Lsn>>;
+    ) -> Result<PageReconstructResult>;
 
-    // Functions that correspond to the Timeline trait functions.
+    /// Return size of the segment at given LSN. (Only for blocky relations.)
     fn get_seg_size(&self, lsn: Lsn) -> Result<u32>;
 
+    /// Does the segment exist at given LSN? Or was it dropped before it.
     fn get_seg_exists(&self, lsn: Lsn) -> Result<bool>;
+
+    /// Does this layer only contain some data for the segment (incremental),
+    /// or does it contain a version of every page? This is important to know
+    /// for garbage collecting old layers: an incremental layer depends on
+    /// the previous non-incremental layer.
+    fn is_incremental(&self) -> bool;
+
+    /// Release memory used by this layer. There is no corresponding 'load'
+    /// function, that's done implicitly when you call one of the get-functions.
+    fn unload(&self) -> Result<()>;
+
+    /// Permanently remove this layer from disk.
+    fn delete(&self) -> Result<()>;
+
+    /// Dump summary of the contents of the layer to stdout
+    fn dump(&self) -> Result<()>;
 }

pageserver/src/lib.rs

@@ -1,3 +1,4 @@
+use layered_repository::{TENANTS_SEGMENT_NAME, TIMELINES_SEGMENT_NAME};
 use zenith_utils::postgres_backend::AuthType;
 use zenith_utils::zid::{ZTenantId, ZTimelineId};
 
@@ -9,21 +10,43 @@ use zenith_metrics::{register_int_gauge_vec, IntGaugeVec};
 
 pub mod basebackup;
 pub mod branches;
+pub mod http;
 pub mod layered_repository;
-pub mod logger;
-pub mod object_key;
-pub mod object_repository;
-pub mod object_store;
-pub mod page_cache;
 pub mod page_service;
 pub mod relish;
+pub mod remote_storage;
 pub mod repository;
 pub mod restore_local_repo;
-pub mod rocksdb_storage;
+pub mod tenant_mgr;
+pub mod tenant_threads;
 pub mod waldecoder;
 pub mod walreceiver;
 pub mod walredo;
 
+pub mod defaults {
+    use const_format::formatcp;
+    use std::time::Duration;
+
+    pub const DEFAULT_PG_LISTEN_PORT: u16 = 64000;
+    pub const DEFAULT_PG_LISTEN_ADDR: &str = formatcp!("127.0.0.1:{DEFAULT_PG_LISTEN_PORT}");
+    pub const DEFAULT_HTTP_LISTEN_PORT: u16 = 9898;
+    pub const DEFAULT_HTTP_LISTEN_ADDR: &str = formatcp!("127.0.0.1:{DEFAULT_HTTP_LISTEN_PORT}");
+
+    // FIXME: This current value is very low. I would imagine something like 1 GB or 10 GB
+    // would be more appropriate. But a low value forces the code to be exercised more,
+    // which is good for now to trigger bugs.
+    pub const DEFAULT_CHECKPOINT_DISTANCE: u64 = 256 * 1024 * 1024;
+    pub const DEFAULT_CHECKPOINT_PERIOD: Duration = Duration::from_secs(1);
+
+    pub const DEFAULT_GC_HORIZON: u64 = 64 * 1024 * 1024;
+    pub const DEFAULT_GC_PERIOD: Duration = Duration::from_secs(100);
+
+    pub const DEFAULT_SUPERUSER: &str = "zenith_admin";
+    pub const DEFAULT_REMOTE_STORAGE_MAX_CONCURRENT_SYNC_LIMITS: usize = 100;
+
+    pub const DEFAULT_OPEN_MEM_LIMIT: usize = 128 * 1024 * 1024;
+}
+
 lazy_static! {
     static ref LIVE_CONNECTIONS_COUNT: IntGaugeVec = register_int_gauge_vec!(
         "pageserver_live_connections_count",
@@ -33,15 +56,25 @@ lazy_static! {
     .expect("failed to define a metric");
 }
 
+pub const LOG_FILE_NAME: &str = "pageserver.log";
+
 #[derive(Debug, Clone)]
 pub struct PageServerConf {
     pub daemonize: bool,
-    pub listen_addr: String,
-    pub http_endpoint_addr: String,
+    pub listen_pg_addr: String,
+    pub listen_http_addr: String,
+    // Flush out an inmemory layer, if it's holding WAL older than this
+    // This puts a backstop on how much WAL needs to be re-digested if the
+    // page server crashes.
+    pub checkpoint_distance: u64,
+    pub checkpoint_period: Duration,
+
     pub gc_horizon: u64,
     pub gc_period: Duration,
     pub superuser: String,
 
+    pub open_mem_limit: usize,
+
     // Repository directory, relative to current working directory.
     // Normally, the page server changes the current working directory
     // to the repository, and 'workdir' is always '.'. But we don't do
@@ -55,14 +88,7 @@ pub struct PageServerConf {
     pub auth_type: AuthType,
 
     pub auth_validation_public_key_path: Option<PathBuf>,
-
-    pub repository_format: RepositoryFormat,
-}
-
-#[derive(Debug, Clone, PartialEq)]
-pub enum RepositoryFormat {
-    Layered,
-    RocksDb,
+    pub remote_storage_config: Option<RemoteStorageConfig>,
 }
 
 impl PageServerConf {
@@ -71,7 +97,7 @@ impl PageServerConf {
     //
 
     fn tenants_path(&self) -> PathBuf {
-        self.workdir.join("tenants")
+        self.workdir.join(TENANTS_SEGMENT_NAME)
     }
 
     fn tenant_path(&self, tenantid: &ZTenantId) -> PathBuf {
@@ -95,7 +121,7 @@ impl PageServerConf {
     }
 
     fn timelines_path(&self, tenantid: &ZTenantId) -> PathBuf {
-        self.tenant_path(tenantid).join("timelines")
+        self.tenant_path(tenantid).join(TIMELINES_SEGMENT_NAME)
     }
 
     fn timeline_path(&self, timelineid: &ZTimelineId, tenantid: &ZTenantId) -> PathBuf {
@@ -106,10 +132,6 @@ impl PageServerConf {
         self.timeline_path(timelineid, tenantid).join("ancestor")
     }
 
-    fn wal_dir_path(&self, timelineid: &ZTimelineId, tenantid: &ZTenantId) -> PathBuf {
-        self.timeline_path(timelineid, tenantid).join("wal")
-    }
-
     //
     // Postgres distribution paths
     //
@@ -121,4 +143,83 @@ impl PageServerConf {
     pub fn pg_lib_dir(&self) -> PathBuf {
         self.pg_distrib_dir.join("lib")
     }
+
+    #[cfg(test)]
+    fn test_repo_dir(test_name: &str) -> PathBuf {
+        PathBuf::from(format!("../tmp_check/test_{}", test_name))
+    }
+
+    #[cfg(test)]
+    fn dummy_conf(repo_dir: PathBuf) -> Self {
+        PageServerConf {
+            daemonize: false,
+            checkpoint_distance: defaults::DEFAULT_CHECKPOINT_DISTANCE,
+            checkpoint_period: Duration::from_secs(10),
+            gc_horizon: defaults::DEFAULT_GC_HORIZON,
+            gc_period: Duration::from_secs(10),
+            open_mem_limit: defaults::DEFAULT_OPEN_MEM_LIMIT,
+            listen_pg_addr: defaults::DEFAULT_PG_LISTEN_ADDR.to_string(),
+            listen_http_addr: defaults::DEFAULT_HTTP_LISTEN_ADDR.to_string(),
+            superuser: "zenith_admin".to_string(),
+            workdir: repo_dir,
+            pg_distrib_dir: "".into(),
+            auth_type: AuthType::Trust,
+            auth_validation_public_key_path: None,
+            remote_storage_config: None,
+        }
+    }
+}
+
+/// Config for the Repository checkpointer
+#[derive(Debug, Clone, Copy)]
+pub enum CheckpointConfig {
+    // Flush in-memory data that is older than this
+    Distance(u64),
+    // Flush all in-memory data
+    Forced,
+}
+
+/// External backup storage configuration, enough for creating a client for that storage.
+#[derive(Debug, Clone)]
+pub struct RemoteStorageConfig {
+    /// Limits the number of concurrent sync operations between pageserver and the remote storage.
+    pub max_concurrent_sync: usize,
+    /// The storage connection configuration.
+    pub storage: RemoteStorageKind,
+}
+
+/// A kind of a remote storage to connect to, with its connection configuration.
+#[derive(Debug, Clone)]
+pub enum RemoteStorageKind {
+    /// Storage based on local file system.
+    /// Specify a root folder to place all stored relish data into.
+    LocalFs(PathBuf),
+    /// AWS S3 based storage, storing all relishes into the root
+    /// of the S3 bucket from the config.
+    AwsS3(S3Config),
+}
+
+/// AWS S3 bucket coordinates and access credentials to manage the bucket contents (read and write).
+#[derive(Clone)]
+pub struct S3Config {
+    /// Name of the bucket to connect to.
+    pub bucket_name: String,
+    /// The region where the bucket is located at.
+    pub bucket_region: String,
+    /// "Login" to use when connecting to bucket.
+    /// Can be empty for cases like AWS k8s IAM
+    /// where we can allow certain pods to connect
+    /// to the bucket directly without any credentials.
+    pub access_key_id: Option<String>,
+    /// "Password" to use when connecting to bucket.
+    pub secret_access_key: Option<String>,
+}
+
+impl std::fmt::Debug for S3Config {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("S3Config")
+            .field("bucket_name", &self.bucket_name)
+            .field("bucket_region", &self.bucket_region)
+            .finish()
+    }
 }

pageserver/src/logger.rs

@@ -1,45 +0,0 @@
-use crate::PageServerConf;
-
-use anyhow::{Context, Result};
-use slog::{Drain, FnValue};
-use std::fs::{File, OpenOptions};
-
-pub fn init_logging(
-    _conf: &PageServerConf,
-    log_filename: &str,
-) -> Result<(slog_scope::GlobalLoggerGuard, File)> {
-    // Don't open the same file for output multiple times;
-    // the different fds could overwrite each other's output.
-    let log_file = OpenOptions::new()
-        .create(true)
-        .append(true)
-        .open(&log_filename)
-        .with_context(|| format!("failed to open {:?}", &log_filename))?;
-
-    let logger_file = log_file.try_clone().unwrap();
-
-    let decorator = slog_term::PlainSyncDecorator::new(logger_file);
-    let drain = slog_term::FullFormat::new(decorator).build();
-    let drain = slog::Filter::new(drain, |record: &slog::Record| {
-        if record.level().is_at_least(slog::Level::Info) {
-            return true;
-        }
-        false
-    });
-    let drain = std::sync::Mutex::new(drain).fuse();
-    let logger = slog::Logger::root(
-        drain,
-        slog::o!(
-            "location" =>
-                FnValue(move |record| {
-                    format!("{}, {}:{}",
-                            record.module(),
-                            record.file(),
-                            record.line()
-                    )
-                }
-                )
-        ),
-    );
-    Ok((slog_scope::set_global_logger(logger), log_file))
-}

pageserver/src/object_key.rs

@@ -1,49 +0,0 @@
-//!
-//! Common structs shared by object_repository.rs and object_store.rs.
-//!
-
-use crate::relish::RelishTag;
-use serde::{Deserialize, Serialize};
-use zenith_utils::zid::ZTimelineId;
-
-///
-/// ObjectKey is the key type used to identify objects stored in an object
-/// repository. It is shared between object_repository.rs and object_store.rs.
-/// It is mostly opaque to ObjectStore, it just stores and retrieves objects
-/// using the key given by the caller.
-///
-#[derive(Debug, Clone, Serialize, Deserialize)]
-pub struct ObjectKey {
-    pub timeline: ZTimelineId,
-    pub tag: ObjectTag,
-}
-
-///
-/// ObjectTag is a part of ObjectKey that is specific to the type of
-/// the stored object.
-///
-/// NB: the order of the enum values is significant!  In particular,
-/// rocksdb_storage.rs assumes that TimelineMetadataTag is first
-///
-/// Buffer is the kind of object that is accessible by the public
-/// get_page_at_lsn() / put_page_image() / put_wal_record() functions in
-/// the repository.rs interface. The rest are internal objects stored in
-/// the key-value store, to store various metadata. They're not directly
-/// accessible outside object_repository.rs
-///
-#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq, PartialOrd, Ord)]
-pub enum ObjectTag {
-    // dummy tag preceeding all other keys
-    FirstTag,
-
-    // Metadata about a timeline. Not versioned.
-    TimelineMetadataTag,
-
-    // These objects store metadata about one relish. Currently it's used
-    // just to track the relish's size. It's not used for non-blocky relishes
-    // at all.
-    RelationMetadata(RelishTag),
-
-    // These are the pages exposed in the public Repository/Timeline interface.
-    Buffer(RelishTag, u32),
-}

pageserver/src/object_store.rs

@@ -1,92 +0,0 @@
-//! Low-level key-value storage abstraction.
-//!
-use crate::object_key::*;
-use crate::relish::*;
-use anyhow::Result;
-use std::collections::HashSet;
-use std::iter::Iterator;
-use zenith_utils::lsn::Lsn;
-use zenith_utils::zid::ZTimelineId;
-
-///
-/// Low-level storage abstraction.
-///
-/// All the data in the repository is stored in a key-value store. This trait
-/// abstracts the details of the key-value store.
-///
-/// A simple key-value store would support just GET and PUT operations with
-/// a key, but the upper layer needs slightly complicated read operations
-///
-/// The most frequently used function is 'object_versions'. It is used
-/// to look up a page version. It is LSN aware, in that the caller
-/// specifies an LSN, and the function returns all values for that
-/// block with the same or older LSN.
-///
-pub trait ObjectStore: Send + Sync {
-    ///
-    /// Store a value with given key.
-    ///
-    fn put(&self, key: &ObjectKey, lsn: Lsn, value: &[u8]) -> Result<()>;
-
-    /// Read entry with the exact given key.
-    ///
-    /// This is used for retrieving metadata with special key that doesn't
-    /// correspond to any real relation.
-    fn get(&self, key: &ObjectKey, lsn: Lsn) -> Result<Vec<u8>>;
-
-    /// Read key greater or equal than specified
-    fn get_next_key(&self, key: &ObjectKey) -> Result<Option<ObjectKey>>;
-
-    /// Iterate through all page versions of one object.
-    ///
-    /// Returns all page versions in descending LSN order, along with the LSN
-    /// of each page version.
-    fn object_versions<'a>(
-        &'a self,
-        key: &ObjectKey,
-        lsn: Lsn,
-    ) -> Result<Box<dyn Iterator<Item = (Lsn, Vec<u8>)> + 'a>>;
-
-    /// Iterate through versions of all objects in a timeline.
-    ///
-    /// Returns objects in increasing key-version order.
-    /// Returns all versions up to and including the specified LSN.
-    fn objects<'a>(
-        &'a self,
-        timeline: ZTimelineId,
-        lsn: Lsn,
-    ) -> Result<Box<dyn Iterator<Item = Result<(ObjectTag, Lsn, Vec<u8>)>> + 'a>>;
-
-    /// Iterate through all keys with given tablespace and database ID, and LSN <= 'lsn'.
-    /// Both dbnode and spcnode can be InvalidId (0) which means get all relations in tablespace/cluster
-    ///
-    /// This is used to implement 'create database'
-    fn list_rels(
-        &self,
-        timelineid: ZTimelineId,
-        spcnode: u32,
-        dbnode: u32,
-        lsn: Lsn,
-    ) -> Result<HashSet<RelTag>>;
-
-    /// Iterate through non-rel relishes
-    ///
-    /// This is used to prepare tarball for new node startup.
-    fn list_nonrels<'a>(&'a self, timelineid: ZTimelineId, lsn: Lsn) -> Result<HashSet<RelishTag>>;
-
-    /// Iterate through objects tags. If nonrel_only, then only non-relationa data is iterated.
-    ///
-    /// This is used to implement GC and preparing tarball for new node startup
-    /// Returns objects in increasing key-version order.
-    fn list_objects<'a>(
-        &'a self,
-        timelineid: ZTimelineId,
-        lsn: Lsn,
-    ) -> Result<Box<dyn Iterator<Item = ObjectTag> + 'a>>;
-
-    /// Unlink object (used by GC). This mehod may actually delete object or just mark it for deletion.
-    fn unlink(&self, key: &ObjectKey, lsn: Lsn) -> Result<()>;
-
-    // Compact storage and remove versions marged for deletion
-    fn compact(&self);
-}

pageserver/src/page_cache.rs

@@ -1,91 +0,0 @@
-//! This module acts as a switchboard to access different repositories managed by this
-//! page server.
-
-use crate::branches;
-use crate::layered_repository::LayeredRepository;
-use crate::object_repository::ObjectRepository;
-use crate::repository::Repository;
-use crate::rocksdb_storage::RocksObjectStore;
-use crate::walredo::PostgresRedoManager;
-use crate::{PageServerConf, RepositoryFormat};
-use anyhow::{anyhow, bail, Result};
-use lazy_static::lazy_static;
-use log::info;
-use std::collections::HashMap;
-use std::fs;
-use std::str::FromStr;
-use std::sync::{Arc, Mutex};
-use zenith_utils::zid::ZTenantId;
-
-lazy_static! {
-    pub static ref REPOSITORY: Mutex<HashMap<ZTenantId, Arc<dyn Repository>>> =
-        Mutex::new(HashMap::new());
-}
-
-pub fn init(conf: &'static PageServerConf) {
-    let mut m = REPOSITORY.lock().unwrap();
-
-    for dir_entry in fs::read_dir(conf.tenants_path()).unwrap() {
-        let tenantid =
-            ZTenantId::from_str(dir_entry.unwrap().file_name().to_str().unwrap()).unwrap();
-
-        // Set up a WAL redo manager, for applying WAL records.
-        let walredo_mgr = PostgresRedoManager::new(conf, tenantid);
-
-        // Set up an object repository, for actual data storage.
-        let repo: Arc<dyn Repository + Sync + Send> = match conf.repository_format {
-            RepositoryFormat::Layered => {
-                let repo = Arc::new(LayeredRepository::new(
-                    conf,
-                    Arc::new(walredo_mgr),
-                    tenantid,
-                ));
-                LayeredRepository::launch_checkpointer_thread(conf, repo.clone());
-                repo
-            }
-            RepositoryFormat::RocksDb => {
-                let obj_store = RocksObjectStore::open(conf, &tenantid).unwrap();
-
-                Arc::new(ObjectRepository::new(
-                    conf,
-                    Arc::new(obj_store),
-                    Arc::new(walredo_mgr),
-                    tenantid,
-                ))
-            }
-        };
-
-        info!("initialized storage for tenant: {}", &tenantid);
-        m.insert(tenantid, repo);
-    }
-}
-
-pub fn create_repository_for_tenant(
-    conf: &'static PageServerConf,
-    tenantid: ZTenantId,
-) -> Result<()> {
-    let mut m = REPOSITORY.lock().unwrap();
-
-    // First check that the tenant doesn't exist already
-    if m.get(&tenantid).is_some() {
-        bail!("tenant {} already exists", tenantid);
-    }
-    let wal_redo_manager = Arc::new(PostgresRedoManager::new(conf, tenantid));
-    let repo = branches::create_repo(conf, tenantid, wal_redo_manager)?;
-
-    m.insert(tenantid, repo);
-
-    Ok(())
-}
-
-pub fn insert_repository_for_tenant(tenantid: ZTenantId, repo: Arc<dyn Repository>) {
-    let o = &mut REPOSITORY.lock().unwrap();
-    o.insert(tenantid, repo);
-}
-
-pub fn get_repository_for_tenant(tenantid: &ZTenantId) -> Result<Arc<dyn Repository>> {
-    let o = &REPOSITORY.lock().unwrap();
-    o.get(tenantid)
-        .map(|repo| Arc::clone(repo))
-        .ok_or_else(|| anyhow!("repository not found for tenant name {}", tenantid))
-}

pageserver/src/page_service.rs

@@ -13,96 +13,133 @@
 use anyhow::{anyhow, bail, ensure, Result};
 use bytes::{Buf, BufMut, Bytes, BytesMut};
 use lazy_static::lazy_static;
-use log::*;
 use regex::Regex;
-use std::io::Write;
 use std::net::TcpListener;
 use std::str;
 use std::str::FromStr;
 use std::sync::Arc;
 use std::thread;
 use std::{io, net::TcpStream};
+use tracing::*;
 use zenith_metrics::{register_histogram_vec, HistogramVec};
-use zenith_utils::auth::JwtAuth;
+use zenith_utils::auth::{self, JwtAuth};
 use zenith_utils::auth::{Claims, Scope};
+use zenith_utils::lsn::Lsn;
+use zenith_utils::postgres_backend::is_socket_read_timed_out;
 use zenith_utils::postgres_backend::PostgresBackend;
 use zenith_utils::postgres_backend::{self, AuthType};
 use zenith_utils::pq_proto::{
     BeMessage, FeMessage, RowDescriptor, HELLO_WORLD_ROW, SINGLE_COL_ROWDESC,
 };
 use zenith_utils::zid::{ZTenantId, ZTimelineId};
-use zenith_utils::{bin_ser::BeSer, lsn::Lsn};
 
 use crate::basebackup;
 use crate::branches;
-use crate::page_cache;
 use crate::relish::*;
-use crate::repository::Modification;
+use crate::repository::Timeline;
+use crate::tenant_mgr;
 use crate::walreceiver;
 use crate::PageServerConf;
 
 // Wrapped in libpq CopyData
 enum PagestreamFeMessage {
-    Exists(PagestreamRequest),
-    Nblocks(PagestreamRequest),
-    Read(PagestreamRequest),
+    Exists(PagestreamExistsRequest),
+    Nblocks(PagestreamNblocksRequest),
+    GetPage(PagestreamGetPageRequest),
 }
 
 // Wrapped in libpq CopyData
 enum PagestreamBeMessage {
-    Status(PagestreamStatusResponse),
-    Nblocks(PagestreamStatusResponse),
-    Read(PagestreamReadResponse),
+    Exists(PagestreamExistsResponse),
+    Nblocks(PagestreamNblocksResponse),
+    GetPage(PagestreamGetPageResponse),
+    Error(PagestreamErrorResponse),
 }
 
 #[derive(Debug)]
-struct PagestreamRequest {
-    spcnode: u32,
-    dbnode: u32,
-    relnode: u32,
-    forknum: u8,
-    blkno: u32,
+struct PagestreamExistsRequest {
+    latest: bool,
     lsn: Lsn,
+    rel: RelTag,
 }
 
 #[derive(Debug)]
-struct PagestreamStatusResponse {
-    ok: bool,
+struct PagestreamNblocksRequest {
+    latest: bool,
+    lsn: Lsn,
+    rel: RelTag,
+}
+
+#[derive(Debug)]
+struct PagestreamGetPageRequest {
+    latest: bool,
+    lsn: Lsn,
+    rel: RelTag,
+    blkno: u32,
+}
+
+#[derive(Debug)]
+struct PagestreamExistsResponse {
+    exists: bool,
+}
+
+#[derive(Debug)]
+struct PagestreamNblocksResponse {
     n_blocks: u32,
 }
 
 #[derive(Debug)]
-struct PagestreamReadResponse {
-    ok: bool,
-    n_blocks: u32,
+struct PagestreamGetPageResponse {
     page: Bytes,
 }
 
+#[derive(Debug)]
+struct PagestreamErrorResponse {
+    message: String,
+}
+
 impl PagestreamFeMessage {
     fn parse(mut body: Bytes) -> anyhow::Result<PagestreamFeMessage> {
         // TODO these gets can fail
 
-        let smgr_tag = body.get_u8();
-        let zreq = PagestreamRequest {
-            spcnode: body.get_u32(),
-            dbnode: body.get_u32(),
-            relnode: body.get_u32(),
-            forknum: body.get_u8(),
-            blkno: body.get_u32(),
-            lsn: Lsn::from(body.get_u64()),
-        };
-
+        // these correspond to the ZenithMessageTag enum in pagestore_client.h
+        //
         // TODO: consider using protobuf or serde bincode for less error prone
         // serialization.
-        match smgr_tag {
-            0 => Ok(PagestreamFeMessage::Exists(zreq)),
-            1 => Ok(PagestreamFeMessage::Nblocks(zreq)),
-            2 => Ok(PagestreamFeMessage::Read(zreq)),
-            _ => Err(anyhow!(
-                "unknown smgr message tag: {},'{:?}'",
-                smgr_tag,
-                body
-            )),
+        let msg_tag = body.get_u8();
+        match msg_tag {
+            0 => Ok(PagestreamFeMessage::Exists(PagestreamExistsRequest {
+                latest: body.get_u8() != 0,
+                lsn: Lsn::from(body.get_u64()),
+                rel: RelTag {
+                    spcnode: body.get_u32(),
+                    dbnode: body.get_u32(),
+                    relnode: body.get_u32(),
+                    forknum: body.get_u8(),
+                },
+            })),
+            1 => Ok(PagestreamFeMessage::Nblocks(PagestreamNblocksRequest {
+                latest: body.get_u8() != 0,
+                lsn: Lsn::from(body.get_u64()),
+                rel: RelTag {
+                    spcnode: body.get_u32(),
+                    dbnode: body.get_u32(),
+                    relnode: body.get_u32(),
+                    forknum: body.get_u8(),
+                },
+            })),
+            2 => Ok(PagestreamFeMessage::GetPage(PagestreamGetPageRequest {
+                latest: body.get_u8() != 0,
+                lsn: Lsn::from(body.get_u64()),
+                rel: RelTag {
+                    spcnode: body.get_u32(),
+                    dbnode: body.get_u32(),
+                    relnode: body.get_u32(),
+                    forknum: body.get_u8(),
+                },
+                blkno: body.get_u32(),
+            })),
+            _ => bail!("unknown smgr message tag: {},'{:?}'", msg_tag, body),
         }
     }
 }
@@ -112,24 +149,26 @@ impl PagestreamBeMessage {
         let mut bytes = BytesMut::new();
 
         match self {
-            Self::Status(resp) => {
+            Self::Exists(resp) => {
                 bytes.put_u8(100); /* tag from pagestore_client.h */
-                bytes.put_u8(resp.ok as u8);
-                bytes.put_u32(resp.n_blocks);
+                bytes.put_u8(resp.exists as u8);
             }
 
             Self::Nblocks(resp) => {
                 bytes.put_u8(101); /* tag from pagestore_client.h */
-                bytes.put_u8(resp.ok as u8);
                 bytes.put_u32(resp.n_blocks);
             }
 
-            Self::Read(resp) => {
+            Self::GetPage(resp) => {
                 bytes.put_u8(102); /* tag from pagestore_client.h */
-                bytes.put_u8(resp.ok as u8);
-                bytes.put_u32(resp.n_blocks);
                 bytes.put(&resp.page[..]);
             }
+
+            Self::Error(resp) => {
+                bytes.put_u8(103); /* tag from pagestore_client.h */
+                bytes.put(resp.message.as_bytes());
+                bytes.put_u8(0); // null terminator
+            }
         }
 
         bytes.into()
@@ -145,26 +184,41 @@ impl PagestreamBeMessage {
 ///
 pub fn thread_main(
     conf: &'static PageServerConf,
-    auth: Arc<Option<JwtAuth>>,
+    auth: Option<Arc<JwtAuth>>,
     listener: TcpListener,
     auth_type: AuthType,
 ) -> anyhow::Result<()> {
-    loop {
+    let mut join_handles = Vec::new();
+
+    while !tenant_mgr::shutdown_requested() {
         let (socket, peer_addr) = listener.accept()?;
         debug!("accepted connection from {}", peer_addr);
         socket.set_nodelay(true).unwrap();
-        let local_auth = Arc::clone(&auth);
-        thread::spawn(move || {
-            if let Err(err) = page_service_conn_main(conf, local_auth, socket, auth_type) {
-                error!("error: {}", err);
-            }
-        });
+        let local_auth = auth.clone();
+
+        let handle = thread::Builder::new()
+            .name("serving Page Service thread".into())
+            .spawn(move || {
+                if let Err(err) = page_service_conn_main(conf, local_auth, socket, auth_type) {
+                    error!(%err, "page server thread exited with error");
+                }
+            })
+            .unwrap();
+
+        join_handles.push(handle);
     }
+
+    debug!("page_service loop terminated. wait for connections to cancel");
+    for handle in join_handles.into_iter() {
+        handle.join().unwrap();
+    }
+
+    Ok(())
 }
 
 fn page_service_conn_main(
     conf: &'static PageServerConf,
-    auth: Arc<Option<JwtAuth>>,
+    auth: Option<Arc<JwtAuth>>,
     socket: TcpStream,
     auth_type: AuthType,
 ) -> anyhow::Result<()> {
@@ -178,14 +232,14 @@ fn page_service_conn_main(
     }
 
     let mut conn_handler = PageServerHandler::new(conf, auth);
-    let pgbackend = PostgresBackend::new(socket, auth_type)?;
+    let pgbackend = PostgresBackend::new(socket, auth_type, None, true)?;
     pgbackend.run(&mut conn_handler)
 }
 
 #[derive(Debug)]
 struct PageServerHandler {
     conf: &'static PageServerConf,
-    auth: Arc<Option<JwtAuth>>,
+    auth: Option<Arc<JwtAuth>>,
     claims: Option<Claims>,
 }
 
@@ -208,7 +262,7 @@ lazy_static! {
 }
 
 impl PageServerHandler {
-    pub fn new(conf: &'static PageServerConf, auth: Arc<Option<JwtAuth>>) -> Self {
+    pub fn new(conf: &'static PageServerConf, auth: Option<Arc<JwtAuth>>) -> Self {
         PageServerHandler {
             conf,
             auth,
@@ -216,125 +270,180 @@ impl PageServerHandler {
         }
     }
 
-    fn handle_controlfile(&self, pgb: &mut PostgresBackend) -> io::Result<()> {
-        pgb.write_message_noflush(&SINGLE_COL_ROWDESC)?
-            .write_message_noflush(&BeMessage::ControlFile)?
-            .write_message(&BeMessage::CommandComplete(b"SELECT 1"))?;
-
-        Ok(())
-    }
-
     fn handle_pagerequests(
         &self,
         pgb: &mut PostgresBackend,
         timelineid: ZTimelineId,
         tenantid: ZTenantId,
     ) -> anyhow::Result<()> {
+        let _enter = info_span!("pagestream", timeline = %timelineid, tenant = %tenantid).entered();
+
         // Check that the timeline exists
-        let repository = page_cache::get_repository_for_tenant(&tenantid)?;
-        let timeline = repository.get_timeline(timelineid).map_err(|_| {
-            anyhow!(
-                "client requested pagestream on timeline {} which does not exist in page server",
-                timelineid
-            )
-        })?;
+        let timeline = tenant_mgr::get_timeline_for_tenant(tenantid, timelineid)?;
 
         /* switch client to COPYBOTH */
         pgb.write_message(&BeMessage::CopyBothResponse)?;
 
-        while let Some(message) = pgb.read_message()? {
-            trace!("query({:?}): {:?}", timelineid, message);
+        while !tenant_mgr::shutdown_requested() {
+            match pgb.read_message() {
+                Ok(message) => {
+                    if let Some(message) = message {
+                        trace!("query: {:?}", message);
 
-            let copy_data_bytes = match message {
-                FeMessage::CopyData(bytes) => bytes,
-                _ => continue,
-            };
+                        let copy_data_bytes = match message {
+                            FeMessage::CopyData(bytes) => bytes,
+                            _ => continue,
+                        };
 
-            let zenith_fe_msg = PagestreamFeMessage::parse(copy_data_bytes)?;
+                        let zenith_fe_msg = PagestreamFeMessage::parse(copy_data_bytes)?;
 
-            let response = match zenith_fe_msg {
-                PagestreamFeMessage::Exists(req) => {
-                    let rel = RelTag {
-                        spcnode: req.spcnode,
-                        dbnode: req.dbnode,
-                        relnode: req.relnode,
-                        forknum: req.forknum,
-                    };
-                    let tag = RelishTag::Relation(rel);
+                        let response = match zenith_fe_msg {
+                            PagestreamFeMessage::Exists(req) => SMGR_QUERY_TIME
+                                .with_label_values(&["get_rel_exists"])
+                                .observe_closure_duration(|| {
+                                    self.handle_get_rel_exists_request(&*timeline, &req)
+                                }),
+                            PagestreamFeMessage::Nblocks(req) => SMGR_QUERY_TIME
+                                .with_label_values(&["get_rel_size"])
+                                .observe_closure_duration(|| {
+                                    self.handle_get_nblocks_request(&*timeline, &req)
+                                }),
+                            PagestreamFeMessage::GetPage(req) => SMGR_QUERY_TIME
+                                .with_label_values(&["get_page_at_lsn"])
+                                .observe_closure_duration(|| {
+                                    self.handle_get_page_at_lsn_request(&*timeline, &req)
+                                }),
+                        };
 
-                    let exist = SMGR_QUERY_TIME
-                        .with_label_values(&["get_rel_exists"])
-                        .observe_closure_duration(|| {
-                            timeline.get_rel_exists(tag, req.lsn).unwrap_or(false)
+                        let response = response.unwrap_or_else(|e| {
+                            // print the all details to the log with {:#}, but for the client the
+                            // error message is enough
+                            error!("error reading relation or page version: {:#}", e);
+                            PagestreamBeMessage::Error(PagestreamErrorResponse {
+                                message: e.to_string(),
+                            })
                         });
 
-                    PagestreamBeMessage::Status(PagestreamStatusResponse {
-                        ok: exist,
-                        n_blocks: 0,
-                    })
+                        pgb.write_message(&BeMessage::CopyData(&response.serialize()))?;
+                    } else {
+                        break;
+                    }
                 }
-                PagestreamFeMessage::Nblocks(req) => {
-                    let rel = RelTag {
-                        spcnode: req.spcnode,
-                        dbnode: req.dbnode,
-                        relnode: req.relnode,
-                        forknum: req.forknum,
-                    };
-                    let tag = RelishTag::Relation(rel);
-
-                    let n_blocks = SMGR_QUERY_TIME
-                        .with_label_values(&["get_rel_size"])
-                        .observe_closure_duration(|| {
-                            // Return 0 if relation is not found.
-                            // This is what postgres smgr expects.
-                            timeline
-                                .get_relish_size(tag, req.lsn)
-                                .unwrap_or(Some(0))
-                                .unwrap_or(0)
-                        });
-
-                    PagestreamBeMessage::Nblocks(PagestreamStatusResponse { ok: true, n_blocks })
+                Err(e) => {
+                    if !is_socket_read_timed_out(&e) {
+                        return Err(e);
+                    }
                 }
-                PagestreamFeMessage::Read(req) => {
-                    let rel = RelTag {
-                        spcnode: req.spcnode,
-                        dbnode: req.dbnode,
-                        relnode: req.relnode,
-                        forknum: req.forknum,
-                    };
-                    let tag = RelishTag::Relation(rel);
-
-                    let read_response = SMGR_QUERY_TIME
-                        .with_label_values(&["get_page_at_lsn"])
-                        .observe_closure_duration(|| {
-                            match timeline.get_page_at_lsn(tag, req.blkno, req.lsn) {
-                                Ok(p) => PagestreamReadResponse {
-                                    ok: true,
-                                    n_blocks: 0,
-                                    page: p,
-                                },
-                                Err(e) => {
-                                    const ZERO_PAGE: [u8; 8192] = [0; 8192];
-                                    error!("get_page_at_lsn: {}", e);
-                                    PagestreamReadResponse {
-                                        ok: false,
-                                        n_blocks: 0,
-                                        page: Bytes::from_static(&ZERO_PAGE),
-                                    }
-                                }
-                            }
-                        });
-
-                    PagestreamBeMessage::Read(read_response)
-                }
-            };
-
-            pgb.write_message(&BeMessage::CopyData(&response.serialize()))?;
+            }
         }
-
         Ok(())
     }
 
+    /// Helper function to handle the LSN from client request.
+    ///
+    /// Each GetPage (and Exists and Nblocks) request includes information about
+    /// which version of the page is being requested. The client can request the
+    /// latest version of the page, or the version that's valid at a particular
+    /// LSN. The primary compute node will always request the latest page
+    /// version, while a standby will request a version at the LSN that it's
+    /// currently caught up to.
+    ///
+    /// In either case, if the page server hasn't received the WAL up to the
+    /// requested LSN yet, we will wait for it to arrive. The return value is
+    /// the LSN that should be used to look up the page versions.
+    fn wait_or_get_last_lsn(timeline: &dyn Timeline, lsn: Lsn, latest: bool) -> Result<Lsn> {
+        if latest {
+            // Latest page version was requested. If LSN is given, it is a hint
+            // to the page server that there have been no modifications to the
+            // page after that LSN. If we haven't received WAL up to that point,
+            // wait until it arrives.
+            let last_record_lsn = timeline.get_last_record_lsn();
+
+            // Note: this covers the special case that lsn == Lsn(0). That
+            // special case means "return the latest version whatever it is",
+            // and it's used for bootstrapping purposes, when the page server is
+            // connected directly to the compute node. That is needed because
+            // when you connect to the compute node, to receive the WAL, the
+            // walsender process will do a look up in the pg_authid catalog
+            // table for authentication. That poses a deadlock problem: the
+            // catalog table lookup will send a GetPage request, but the GetPage
+            // request will block in the page server because the recent WAL
+            // hasn't been received yet, and it cannot be received until the
+            // walsender completes the authentication and starts streaming the
+            // WAL.
+            if lsn <= last_record_lsn {
+                Ok(last_record_lsn)
+            } else {
+                timeline.wait_lsn(lsn)?;
+                // Since we waited for 'lsn' to arrive, that is now the last
+                // record LSN. (Or close enough for our purposes; the
+                // last-record LSN can advance immediately after we return
+                // anyway)
+                Ok(lsn)
+            }
+        } else {
+            if lsn == Lsn(0) {
+                bail!("invalid LSN(0) in request");
+            }
+            timeline.wait_lsn(lsn)?;
+            Ok(lsn)
+        }
+    }
+
+    fn handle_get_rel_exists_request(
+        &self,
+        timeline: &dyn Timeline,
+        req: &PagestreamExistsRequest,
+    ) -> Result<PagestreamBeMessage> {
+        let _enter = info_span!("get_rel_exists", rel = %req.rel, req_lsn = %req.lsn).entered();
+
+        let tag = RelishTag::Relation(req.rel);
+        let lsn = Self::wait_or_get_last_lsn(timeline, req.lsn, req.latest)?;
+
+        let exists = timeline.get_rel_exists(tag, lsn)?;
+
+        Ok(PagestreamBeMessage::Exists(PagestreamExistsResponse {
+            exists,
+        }))
+    }
+
+    fn handle_get_nblocks_request(
+        &self,
+        timeline: &dyn Timeline,
+        req: &PagestreamNblocksRequest,
+    ) -> Result<PagestreamBeMessage> {
+        let _enter = info_span!("get_nblocks", rel = %req.rel, req_lsn = %req.lsn).entered();
+        let tag = RelishTag::Relation(req.rel);
+        let lsn = Self::wait_or_get_last_lsn(timeline, req.lsn, req.latest)?;
+
+        let n_blocks = timeline.get_relish_size(tag, lsn)?;
+
+        // Return 0 if relation is not found.
+        // This is what postgres smgr expects.
+        let n_blocks = n_blocks.unwrap_or(0);
+
+        Ok(PagestreamBeMessage::Nblocks(PagestreamNblocksResponse {
+            n_blocks,
+        }))
+    }
+
+    fn handle_get_page_at_lsn_request(
+        &self,
+        timeline: &dyn Timeline,
+        req: &PagestreamGetPageRequest,
+    ) -> Result<PagestreamBeMessage> {
+        let _enter = info_span!("get_page", rel = %req.rel, blkno = &req.blkno, req_lsn = %req.lsn)
+            .entered();
+        let tag = RelishTag::Relation(req.rel);
+        let lsn = Self::wait_or_get_last_lsn(timeline, req.lsn, req.latest)?;
+
+        let page = timeline.get_page_at_lsn(tag, req.blkno, lsn)?;
+
+        Ok(PagestreamBeMessage::GetPage(PagestreamGetPageResponse {
+            page,
+        }))
+    }
+
     fn handle_basebackup_request(
         &self,
         pgb: &mut PostgresBackend,
@@ -342,36 +451,20 @@ impl PageServerHandler {
         lsn: Option<Lsn>,
         tenantid: ZTenantId,
     ) -> anyhow::Result<()> {
+        let span = info_span!("basebackup", timeline = %timelineid, tenant = %tenantid, lsn = field::Empty);
+        let _enter = span.enter();
+
         // check that the timeline exists
-        let repository = page_cache::get_repository_for_tenant(&tenantid)?;
-        let timeline = repository.get_timeline(timelineid).map_err(|e| {
-            error!("error fetching timeline: {:?}", e);
-            anyhow!(
-                "client requested basebackup on timeline {} which does not exist in page server",
-                timelineid
-            )
-        })?;
-        /* switch client to COPYOUT */
+        let timeline = tenant_mgr::get_timeline_for_tenant(tenantid, timelineid)?;
+
+        // switch client to COPYOUT
         pgb.write_message(&BeMessage::CopyOutResponse)?;
-        info!("sent CopyOut");
 
-        /* Send a tarball of the latest snapshot on the timeline */
-
-        let req_lsn = match lsn {
-            Some(lsn) => {
-                timeline.wait_lsn(lsn)?;
-                lsn
-            }
-            None => timeline.get_last_record_lsn(),
-        };
+        /* Send a tarball of the latest layer on the timeline */
         {
             let mut writer = CopyDataSink { pgb };
-            let mut basebackup = basebackup::Basebackup::new(
-                &mut writer,
-                &timeline,
-                req_lsn,
-                timeline.get_prev_record_lsn(),
-            );
+            let mut basebackup = basebackup::Basebackup::new(&mut writer, &timeline, lsn)?;
+            span.record("lsn", &basebackup.lsn.to_string().as_str());
             basebackup.send_tarball()?;
         }
         pgb.write_message(&BeMessage::CopyDone)?;
@@ -394,19 +487,7 @@ impl PageServerHandler {
             .claims
             .as_ref()
             .expect("claims presence already checked");
-        match (&claims.scope, tenantid) {
-            (Scope::Tenant, None) => {
-                bail!("Attempt to access management api with tenant scope. Permission denied")
-            }
-            (Scope::Tenant, Some(tenantid)) => {
-                if claims.tenant_id.unwrap() != tenantid {
-                    bail!("Tenant id mismatch. Permission denied")
-                }
-                Ok(())
-            }
-            (Scope::PageServerApi, None) => Ok(()), // access to management api for PageServerApi scope
-            (Scope::PageServerApi, Some(_)) => Ok(()), // access to tenant api using PageServerApi scope
-        }
+        auth::check_permission(claims, tenantid)
     }
 }
 
@@ -423,7 +504,7 @@ impl postgres_backend::Handler for PageServerHandler {
             .as_ref()
             .as_ref()
             .unwrap()
-            .decode(&str::from_utf8(jwt_response)?)?;
+            .decode(str::from_utf8(jwt_response)?)?;
 
         if matches!(data.claims.scope, Scope::Tenant) {
             ensure!(
@@ -455,11 +536,9 @@ impl postgres_backend::Handler for PageServerHandler {
         }
         let query_string = std::str::from_utf8(&query_string)?;
 
-        if query_string.starts_with("controlfile") {
-            self.handle_controlfile(pgb)?;
-        } else if query_string.starts_with("pagestream ") {
+        if query_string.starts_with("pagestream ") {
             let (_, params_raw) = query_string.split_at("pagestream ".len());
-            let params = params_raw.split(" ").collect::<Vec<_>>();
+            let params = params_raw.split(' ').collect::<Vec<_>>();
             ensure!(
                 params.len() == 2,
                 "invalid param number for pagestream command"
@@ -472,7 +551,8 @@ impl postgres_backend::Handler for PageServerHandler {
             self.handle_pagerequests(pgb, timelineid, tenantid)?;
         } else if query_string.starts_with("basebackup ") {
             let (_, params_raw) = query_string.split_at("basebackup ".len());
-            let params = params_raw.split(" ").collect::<Vec<_>>();
+            let params = params_raw.split_whitespace().collect::<Vec<_>>();
+
             ensure!(
                 params.len() >= 2,
                 "invalid param number for basebackup command"
@@ -483,16 +563,11 @@ impl postgres_backend::Handler for PageServerHandler {
 
             self.check_permission(Some(tenantid))?;
 
-            // TODO are there any tests with lsn option?
-            let lsn = if params.len() == 3 && params[2].len() != 0 {
+            let lsn = if params.len() == 3 {
                 Some(Lsn::from_str(params[2])?)
             } else {
                 None
             };
-            info!(
-                "got basebackup command. tenantid=\"{}\" timelineid=\"{}\" lsn=\"{:#?}\"",
-                tenantid, timelineid, lsn
-            );
 
             // Check that the timeline exists
             self.handle_basebackup_request(pgb, timelineid, lsn, tenantid)?;
@@ -511,13 +586,13 @@ impl postgres_backend::Handler for PageServerHandler {
 
             self.check_permission(Some(tenantid))?;
 
-            // Check that the timeline exists
-            let repository = page_cache::get_repository_for_tenant(&tenantid)?;
-            if repository.get_timeline(timelineid).is_err() {
-                bail!("client requested callmemaybe on timeline {} which does not exist in page server", timelineid);
-            }
+            let _enter =
+                info_span!("callmemaybe", timeline = %timelineid, tenant = %tenantid).entered();
 
-            walreceiver::launch_wal_receiver(&self.conf, timelineid, &connstr, tenantid.to_owned());
+            // Check that the timeline exists
+            tenant_mgr::get_timeline_for_tenant(tenantid, timelineid)?;
+
+            walreceiver::launch_wal_receiver(self.conf, timelineid, &connstr, tenantid.to_owned());
 
             pgb.write_message_noflush(&BeMessage::CommandComplete(b"SELECT 1"))?;
         } else if query_string.starts_with("branch_create ") {
@@ -525,10 +600,10 @@ impl postgres_backend::Handler for PageServerHandler {
 
             // branch_create <tenantid> <branchname> <startpoint>
             // TODO lazy static
-            // TOOD: escaping, to allow branch names with spaces
+            // TODO: escaping, to allow branch names with spaces
             let re = Regex::new(r"^branch_create ([[:xdigit:]]+) (\S+) ([^\r\n\s;]+)[\r\n\s;]*;?$")
                 .unwrap();
-            let caps = re.captures(&query_string).ok_or_else(err)?;
+            let caps = re.captures(query_string).ok_or_else(err)?;
 
             let tenantid = ZTenantId::from_str(caps.get(1).unwrap().as_str())?;
             let branchname = caps.get(2).ok_or_else(err)?.as_str().to_owned();
@@ -536,91 +611,16 @@ impl postgres_backend::Handler for PageServerHandler {
 
             self.check_permission(Some(tenantid))?;
 
+            let _enter =
+                info_span!("branch_create", name = %branchname, tenant = %tenantid).entered();
+
             let branch =
-                branches::create_branch(&self.conf, &branchname, &startpoint_str, &tenantid)?;
+                branches::create_branch(self.conf, &branchname, &startpoint_str, &tenantid)?;
             let branch = serde_json::to_vec(&branch)?;
 
             pgb.write_message_noflush(&SINGLE_COL_ROWDESC)?
                 .write_message_noflush(&BeMessage::DataRow(&[Some(&branch)]))?
                 .write_message_noflush(&BeMessage::CommandComplete(b"SELECT 1"))?;
-        } else if query_string.starts_with("push ") {
-            // push <zenith tenantid as hex string> <zenith timelineid as hex string>
-            let re = Regex::new(r"^push ([[:xdigit:]]+) ([[:xdigit:]]+)$").unwrap();
-
-            let caps = re
-                .captures(query_string)
-                .ok_or_else(|| anyhow!("invalid push: '{}'", query_string))?;
-
-            let tenantid = ZTenantId::from_str(caps.get(1).unwrap().as_str())?;
-            let timelineid = ZTimelineId::from_str(caps.get(2).unwrap().as_str())?;
-
-            self.check_permission(Some(tenantid))?;
-
-            let start_lsn = Lsn(0); // TODO this needs to come from the repo
-            let timeline = page_cache::get_repository_for_tenant(&tenantid)?
-                .create_empty_timeline(timelineid, start_lsn)?;
-
-            pgb.write_message(&BeMessage::CopyInResponse)?;
-
-            let mut last_lsn = Lsn(0);
-
-            while let Some(msg) = pgb.read_message()? {
-                match msg {
-                    FeMessage::CopyData(bytes) => {
-                        let modification = Modification::des(&bytes)?;
-
-                        last_lsn = modification.lsn;
-                        timeline.put_raw_data(
-                            modification.tag,
-                            modification.lsn,
-                            &modification.data,
-                        )?;
-                    }
-                    FeMessage::CopyDone => {
-                        timeline.advance_last_valid_lsn(last_lsn);
-                        break;
-                    }
-                    FeMessage::CopyFailed => {
-                        info!("Copy failed");
-                        break;
-                    }
-                    FeMessage::Sync => {}
-                    _ => bail!("unexpected message {:?}", msg),
-                }
-            }
-
-            pgb.write_message_noflush(&BeMessage::CommandComplete(b"SELECT 1"))?;
-        } else if query_string.starts_with("request_push ") {
-            // request_push <zenith tenantid as hex string> <zenith timelineid as hex string> <postgres_connection_uri>
-            let re = Regex::new(r"^request_push ([[:xdigit:]]+) ([[:xdigit:]]+) (.*)$").unwrap();
-
-            let caps = re
-                .captures(query_string)
-                .ok_or_else(|| anyhow!("invalid request_push: '{}'", query_string))?;
-
-            let tenantid = ZTenantId::from_str(caps.get(1).unwrap().as_str())?;
-            let timelineid = ZTimelineId::from_str(caps.get(2).unwrap().as_str())?;
-            let postgres_connection_uri = caps.get(3).unwrap().as_str();
-
-            self.check_permission(Some(tenantid))?;
-
-            let timeline =
-                page_cache::get_repository_for_tenant(&tenantid)?.get_timeline(timelineid)?;
-
-            let mut conn = postgres::Client::connect(postgres_connection_uri, postgres::NoTls)?;
-            let mut copy_in = conn.copy_in(format!("push {}", timelineid.to_string()).as_str())?;
-
-            let history = timeline.history()?;
-            for update_res in history {
-                let update = update_res?;
-                let update_bytes = update.ser()?;
-                copy_in.write_all(&update_bytes)?;
-                copy_in.flush()?; // ensure that messages are sent inside individual CopyData packets
-            }
-
-            copy_in.finish()?;
-
-            pgb.write_message_noflush(&BeMessage::CommandComplete(b"SELECT 1"))?;
         } else if query_string.starts_with("branch_list ") {
             // branch_list <zenith tenantid as hex string>
             let re = Regex::new(r"^branch_list ([[:xdigit:]]+)$").unwrap();
@@ -630,14 +630,16 @@ impl postgres_backend::Handler for PageServerHandler {
 
             let tenantid = ZTenantId::from_str(caps.get(1).unwrap().as_str())?;
 
-            let branches = crate::branches::get_branches(&self.conf, &tenantid)?;
+            // since these handlers for tenant/branch commands are deprecated (in favor of http based ones)
+            // just use false in place of include non incremental logical size
+            let branches = crate::branches::get_branches(self.conf, &tenantid, false)?;
             let branches_buf = serde_json::to_vec(&branches)?;
 
             pgb.write_message_noflush(&SINGLE_COL_ROWDESC)?
                 .write_message_noflush(&BeMessage::DataRow(&[Some(&branches_buf)]))?
                 .write_message_noflush(&BeMessage::CommandComplete(b"SELECT 1"))?;
         } else if query_string.starts_with("tenant_list") {
-            let tenants = crate::branches::get_tenants(&self.conf)?;
+            let tenants = crate::tenant_mgr::list_tenants()?;
             let tenants_buf = serde_json::to_vec(&tenants)?;
 
             pgb.write_message_noflush(&SINGLE_COL_ROWDESC)?
@@ -648,13 +650,13 @@ impl postgres_backend::Handler for PageServerHandler {
 
             // tenant_create <tenantid>
             let re = Regex::new(r"^tenant_create ([[:xdigit:]]+)$").unwrap();
-            let caps = re.captures(&query_string).ok_or_else(err)?;
+            let caps = re.captures(query_string).ok_or_else(err)?;
 
             self.check_permission(None)?;
 
             let tenantid = ZTenantId::from_str(caps.get(1).unwrap().as_str())?;
 
-            page_cache::create_repository_for_tenant(&self.conf, tenantid)?;
+            tenant_mgr::create_repository_for_tenant(self.conf, tenantid)?;
 
             pgb.write_message_noflush(&SINGLE_COL_ROWDESC)?
                 .write_message_noflush(&BeMessage::CommandComplete(b"SELECT 1"))?;
@@ -688,82 +690,73 @@ impl postgres_backend::Handler for PageServerHandler {
                 .map(|h| h.as_str().parse())
                 .unwrap_or(Ok(self.conf.gc_horizon))?;
 
-            let repo = page_cache::get_repository_for_tenant(&tenantid)?;
+            let repo = tenant_mgr::get_repository_for_tenant(tenantid)?;
 
             let result = repo.gc_iteration(Some(timelineid), gc_horizon, true)?;
 
             pgb.write_message_noflush(&BeMessage::RowDescription(&[
-                RowDescriptor::int8_col(b"n_relations"),
-                RowDescriptor::int8_col(b"truncated"),
-                RowDescriptor::int8_col(b"deleted"),
-                RowDescriptor::int8_col(b"prep_deleted"),
-                RowDescriptor::int8_col(b"slru_deleted"),
-                RowDescriptor::int8_col(b"chkp_deleted"),
-                RowDescriptor::int8_col(b"control_deleted"),
-                RowDescriptor::int8_col(b"filenodemap_deleted"),
-                RowDescriptor::int8_col(b"dropped"),
-                RowDescriptor::int8_col(b"snapshot_relfiles_total"),
-                RowDescriptor::int8_col(b"snapshot_relfiles_needed_by_cutoff"),
-                RowDescriptor::int8_col(b"snapshot_relfiles_needed_by_branches"),
-                RowDescriptor::int8_col(b"snapshot_relfiles_not_updated"),
-                RowDescriptor::int8_col(b"snapshot_relfiles_removed"),
-                RowDescriptor::int8_col(b"snapshot_relfiles_dropped"),
-                RowDescriptor::int8_col(b"snapshot_nonrelfiles_total"),
-                RowDescriptor::int8_col(b"snapshot_nonrelfiles_needed_by_cutoff"),
-                RowDescriptor::int8_col(b"snapshot_nonrelfiles_needed_by_branches"),
-                RowDescriptor::int8_col(b"snapshot_nonrelfiles_not_updated"),
-                RowDescriptor::int8_col(b"snapshot_nonrelfiles_removed"),
-                RowDescriptor::int8_col(b"snapshot_nonrelfiles_dropped"),
+                RowDescriptor::int8_col(b"layer_relfiles_total"),
+                RowDescriptor::int8_col(b"layer_relfiles_needed_by_cutoff"),
+                RowDescriptor::int8_col(b"layer_relfiles_needed_by_branches"),
+                RowDescriptor::int8_col(b"layer_relfiles_not_updated"),
+                RowDescriptor::int8_col(b"layer_relfiles_needed_as_tombstone"),
+                RowDescriptor::int8_col(b"layer_relfiles_removed"),
+                RowDescriptor::int8_col(b"layer_relfiles_dropped"),
+                RowDescriptor::int8_col(b"layer_nonrelfiles_total"),
+                RowDescriptor::int8_col(b"layer_nonrelfiles_needed_by_cutoff"),
+                RowDescriptor::int8_col(b"layer_nonrelfiles_needed_by_branches"),
+                RowDescriptor::int8_col(b"layer_nonrelfiles_not_updated"),
+                RowDescriptor::int8_col(b"layer_nonrelfiles_needed_as_tombstone"),
+                RowDescriptor::int8_col(b"layer_nonrelfiles_removed"),
+                RowDescriptor::int8_col(b"layer_nonrelfiles_dropped"),
                 RowDescriptor::int8_col(b"elapsed"),
             ]))?
             .write_message_noflush(&BeMessage::DataRow(&[
-                Some(&result.n_relations.to_string().as_bytes()),
-                Some(&result.truncated.to_string().as_bytes()),
-                Some(&result.deleted.to_string().as_bytes()),
-                Some(&result.prep_deleted.to_string().as_bytes()),
-                Some(&result.slru_deleted.to_string().as_bytes()),
-                Some(&result.chkp_deleted.to_string().as_bytes()),
-                Some(&result.control_deleted.to_string().as_bytes()),
-                Some(&result.filenodemap_deleted.to_string().as_bytes()),
-                Some(&result.dropped.to_string().as_bytes()),
-                Some(&result.snapshot_relfiles_total.to_string().as_bytes()),
+                Some(result.ondisk_relfiles_total.to_string().as_bytes()),
                 Some(
-                    &result
-                        .snapshot_relfiles_needed_by_cutoff
+                    result
+                        .ondisk_relfiles_needed_by_cutoff
                         .to_string()
                         .as_bytes(),
                 ),
                 Some(
-                    &result
-                        .snapshot_relfiles_needed_by_branches
+                    result
+                        .ondisk_relfiles_needed_by_branches
                         .to_string()
                         .as_bytes(),
                 ),
-                Some(&result.snapshot_relfiles_not_updated.to_string().as_bytes()),
-                Some(&result.snapshot_relfiles_removed.to_string().as_bytes()),
-                Some(&result.snapshot_relfiles_dropped.to_string().as_bytes()),
-                Some(&result.snapshot_nonrelfiles_total.to_string().as_bytes()),
+                Some(result.ondisk_relfiles_not_updated.to_string().as_bytes()),
                 Some(
-                    &result
-                        .snapshot_nonrelfiles_needed_by_cutoff
+                    result
+                        .ondisk_relfiles_needed_as_tombstone
+                        .to_string()
+                        .as_bytes(),
+                ),
+                Some(result.ondisk_relfiles_removed.to_string().as_bytes()),
+                Some(result.ondisk_relfiles_dropped.to_string().as_bytes()),
+                Some(result.ondisk_nonrelfiles_total.to_string().as_bytes()),
+                Some(
+                    result
+                        .ondisk_nonrelfiles_needed_by_cutoff
                         .to_string()
                         .as_bytes(),
                 ),
                 Some(
-                    &result
-                        .snapshot_nonrelfiles_needed_by_branches
+                    result
+                        .ondisk_nonrelfiles_needed_by_branches
                         .to_string()
                         .as_bytes(),
                 ),
+                Some(result.ondisk_nonrelfiles_not_updated.to_string().as_bytes()),
                 Some(
-                    &result
-                        .snapshot_nonrelfiles_not_updated
+                    result
+                        .ondisk_nonrelfiles_needed_as_tombstone
                         .to_string()
                         .as_bytes(),
                 ),
-                Some(&result.snapshot_nonrelfiles_removed.to_string().as_bytes()),
-                Some(&result.snapshot_nonrelfiles_dropped.to_string().as_bytes()),
-                Some(&result.elapsed.as_millis().to_string().as_bytes()),
+                Some(result.ondisk_nonrelfiles_removed.to_string().as_bytes()),
+                Some(result.ondisk_nonrelfiles_dropped.to_string().as_bytes()),
+                Some(result.elapsed.as_millis().to_string().as_bytes()),
             ]))?
             .write_message(&BeMessage::CommandComplete(b"SELECT 1"))?;
         } else {

pageserver/src/relish.rs

@@ -125,11 +125,7 @@ impl RelishTag {
 
     // convenience function to check if this relish is a normal relation.
     pub const fn is_relation(&self) -> bool {
-        if let RelishTag::Relation(_) = self {
-            true
-        } else {
-            false
-        }
+        matches!(self, RelishTag::Relation(_))
     }
 }
 

pageserver/src/remote_storage.rs

@@ -0,0 +1,322 @@
+//! A set of generic storage abstractions for the page server to use when backing up and restoring its state from the external storage.
+//! This particular module serves as a public API border between pageserver and the internal storage machinery.
+//! No other modules from this tree are supposed to be used directly by the external code.
+//!
+//! There are a few components the storage machinery consists of:
+//! * [`RemoteStorage`] trait a CRUD-like generic abstraction to use for adapting external storages with a few implementations:
+//!     * [`local_fs`] allows to use local file system as an external storage
+//!     * [`rust_s3`] uses AWS S3 bucket entirely as an external storage
+//!
+//! * synchronization logic at [`storage_sync`] module that keeps pageserver state (both runtime one and the workdir files) and storage state in sync.
+//!
+//! * public API via to interact with the external world: [`run_storage_sync_thread`] and [`schedule_timeline_upload`]
+//!
+//! Here's a schematic overview of all interactions backup and the rest of the pageserver perform:
+//!
+//! +------------------------+                                    +--------->-------+
+//! |                        |  - - - (init async loop) - - - ->  |                 |
+//! |                        |                                    |                 |
+//! |                        |  ------------------------------->  |      async      |
+//! |       pageserver       |   (schedule frozen layer upload)   | upload/download |
+//! |                        |                                    |      loop       |
+//! |                        |  <-------------------------------  |                 |
+//! |                        |    (register downloaded layers)    |                 |
+//! +------------------------+                                    +---------<-------+
+//!                                                                         |
+//!                                                                         |
+//!                                          CRUD layer file operations     |
+//!                                     (upload/download/delete/list, etc.) |
+//!                                                                         V
+//!                                                            +------------------------+
+//!                                                            |                        |
+//!                                                            | [`RemoteStorage`] impl |
+//!                                                            |                        |
+//!                                                            | pageserver assumes it  |
+//!                                                            | owns exclusive write   |
+//!                                                            | access to this storage |
+//!                                                            +------------------------+
+//!
+//! First, during startup, the pageserver inits the storage sync thread with the async loop, or leaves the loop unitialised, if configured so.
+//! Some time later, during pageserver checkpoints, in-memory data is flushed onto disk along with its metadata.
+//! If the storage sync loop was successfully started before, pageserver schedules the new image uploads after every checkpoint.
+//! See [`crate::layered_repository`] for the upload calls and the adjacent logic.
+//!
+//! The storage logic considers `image` as a set of local files, fully representing a certain timeline at given moment (identified with `disk_consistent_lsn`).
+//! Timeline can change its state, by adding more files on disk and advancing its `disk_consistent_lsn`: this happens after pageserver checkpointing and is followed
+//! by the storage upload, if enabled.
+//! When a certain image gets uploaded, the sync loop remembers the fact, preventing further reuploads of the same image state.
+//! No files are deleted from either local or remote storage, only the missing ones locally/remotely get downloaded/uploaded, local metadata file will be overwritten
+//! when the newer timeline is downloaded.
+//!
+//! Meanwhile, the loop inits the storage connection and checks the remote files stored.
+//! This is done once at startup only, relying on the fact that pageserver uses the storage alone (ergo, nobody else uploads the files to the storage but this server).
+//! Based on the remote image data, the storage sync logic queues image downloads, while accepting any potential upload tasks from pageserver and managing the tasks by their priority.
+//! On the image download, a [`crate::tenant_mgr::register_relish_download`] function is called to register the new image in pageserver, initializing all related threads and internal state.
+//!
+//! When the pageserver terminates, the upload loop finishes a current image sync task (if any) and exits.
+//!
+//! NOTES:
+//! * pageserver assumes it has exclusive write access to the remote storage. If supported, the way multiple pageservers can be separated in the same storage
+//! (i.e. using different directories in the local filesystem external storage), but totally up to the storage implementation and not covered with the trait API.
+//!
+//! * the uploads do not happen right after pageserver startup, they are registered when
+//!     1. pageserver does the checkpoint, which happens further in the future after the server start
+//!     2. pageserver loads the timeline from disk for the first time
+//!
+//! * the uploads do not happen right after the upload registration: the sync loop might be occupied with other tasks, or tasks with bigger priority could be waiting already
+//!
+//! * all synchronization tasks (including the public API to register uploads and downloads and the sync queue management) happens on an image scale: a big set of remote files,
+//! enough to represent (and recover, if needed) a certain timeline state. On the contrary, all internal storage CRUD calls are made per reilsh file from those images.
+//! This way, the synchronization is able to download the image partially, if some state was synced before, but exposes correctly synced images only.
+
+mod local_fs;
+mod rust_s3;
+mod storage_sync;
+
+use std::{
+    path::{Path, PathBuf},
+    thread,
+};
+
+use anyhow::{anyhow, ensure, Context};
+use tokio::io;
+use zenith_utils::zid::{ZTenantId, ZTimelineId};
+
+pub use self::storage_sync::schedule_timeline_upload;
+use self::{local_fs::LocalFs, rust_s3::S3};
+use crate::{
+    layered_repository::{TENANTS_SEGMENT_NAME, TIMELINES_SEGMENT_NAME},
+    PageServerConf, RemoteStorageKind,
+};
+
+/// Based on the config, initiates the remote storage connection and starts a separate thread
+/// that ensures that pageserver and the remote storage are in sync with each other.
+/// If no external configuraion connection given, no thread or storage initialization is done.
+pub fn run_storage_sync_thread(
+    config: &'static PageServerConf,
+) -> anyhow::Result<Option<thread::JoinHandle<anyhow::Result<()>>>> {
+    match &config.remote_storage_config {
+        Some(storage_config) => {
+            let max_concurrent_sync = storage_config.max_concurrent_sync;
+            let handle = match &storage_config.storage {
+                RemoteStorageKind::LocalFs(root) => storage_sync::spawn_storage_sync_thread(
+                    config,
+                    LocalFs::new(root.clone(), &config.workdir)?,
+                    max_concurrent_sync,
+                ),
+                RemoteStorageKind::AwsS3(s3_config) => storage_sync::spawn_storage_sync_thread(
+                    config,
+                    S3::new(s3_config, &config.workdir)?,
+                    max_concurrent_sync,
+                ),
+            };
+            handle.map(Some)
+        }
+        None => Ok(None),
+    }
+}
+
+/// Storage (potentially remote) API to manage its state.
+/// This storage tries to be unaware of any layered repository context,
+/// providing basic CRUD operations with storage files.
+#[async_trait::async_trait]
+trait RemoteStorage: Send + Sync {
+    /// A way to uniquely reference a file in the remote storage.
+    type StoragePath;
+
+    /// Attempts to derive the storage path out of the local path, if the latter is correct.
+    fn storage_path(&self, local_path: &Path) -> anyhow::Result<Self::StoragePath>;
+
+    /// Gets the layered storage information about the given entry.
+    fn info(&self, storage_path: &Self::StoragePath) -> anyhow::Result<RemoteFileInfo>;
+
+    /// Lists all items the storage has right now.
+    async fn list(&self) -> anyhow::Result<Vec<Self::StoragePath>>;
+
+    /// Streams the local file contents into remote into the remote storage entry.
+    async fn upload(
+        &self,
+        from: impl io::AsyncRead + Unpin + Send + Sync + 'static,
+        to: &Self::StoragePath,
+    ) -> anyhow::Result<()>;
+
+    /// Streams the remote storage entry contents into the buffered writer given, returns the filled writer.
+    async fn download(
+        &self,
+        from: &Self::StoragePath,
+        to: &mut (impl io::AsyncWrite + Unpin + Send + Sync),
+    ) -> anyhow::Result<()>;
+
+    async fn delete(&self, path: &Self::StoragePath) -> anyhow::Result<()>;
+}
+
+/// Information about a certain remote storage entry.
+#[derive(Debug, PartialEq, Eq)]
+struct RemoteFileInfo {
+    tenant_id: ZTenantId,
+    timeline_id: ZTimelineId,
+    /// Path in the pageserver workdir where the file should go to.
+    download_destination: PathBuf,
+    is_metadata: bool,
+}
+
+fn strip_path_prefix<'a>(prefix: &'a Path, path: &'a Path) -> anyhow::Result<&'a Path> {
+    if prefix == path {
+        anyhow::bail!(
+            "Prefix and the path are equal, cannot strip: '{}'",
+            prefix.display()
+        )
+    } else {
+        path.strip_prefix(prefix).with_context(|| {
+            format!(
+                "Path '{}' is not prefixed with '{}'",
+                path.display(),
+                prefix.display(),
+            )
+        })
+    }
+}
+
+fn parse_ids_from_path<'a, R: std::fmt::Display>(
+    path_segments: impl Iterator<Item = &'a str>,
+    path_log_representation: &R,
+) -> anyhow::Result<(ZTenantId, ZTimelineId)> {
+    let mut segments = path_segments.skip_while(|&segment| segment != TENANTS_SEGMENT_NAME);
+    let tenants_segment = segments.next().ok_or_else(|| {
+        anyhow!(
+            "Found no '{}' segment in the storage path '{}'",
+            TENANTS_SEGMENT_NAME,
+            path_log_representation
+        )
+    })?;
+    ensure!(
+        tenants_segment == TENANTS_SEGMENT_NAME,
+        "Failed to extract '{}' segment from storage path '{}'",
+        TENANTS_SEGMENT_NAME,
+        path_log_representation
+    );
+    let tenant_id = segments
+        .next()
+        .ok_or_else(|| {
+            anyhow!(
+                "Found no tenant id in the storage path '{}'",
+                path_log_representation
+            )
+        })?
+        .parse::<ZTenantId>()
+        .with_context(|| {
+            format!(
+                "Failed to parse tenant id from storage path '{}'",
+                path_log_representation
+            )
+        })?;
+
+    let timelines_segment = segments.next().ok_or_else(|| {
+        anyhow!(
+            "Found no '{}' segment in the storage path '{}'",
+            TIMELINES_SEGMENT_NAME,
+            path_log_representation
+        )
+    })?;
+    ensure!(
+        timelines_segment == TIMELINES_SEGMENT_NAME,
+        "Failed to extract '{}' segment from storage path '{}'",
+        TIMELINES_SEGMENT_NAME,
+        path_log_representation
+    );
+    let timeline_id = segments
+        .next()
+        .ok_or_else(|| {
+            anyhow!(
+                "Found no timeline id in the storage path '{}'",
+                path_log_representation
+            )
+        })?
+        .parse::<ZTimelineId>()
+        .with_context(|| {
+            format!(
+                "Failed to parse timeline id from storage path '{}'",
+                path_log_representation
+            )
+        })?;
+
+    Ok((tenant_id, timeline_id))
+}
+
+/// A set of common test utils to share in unit tests inside the module tree.
+#[cfg(test)]
+mod test_utils {
+    use std::path::{Path, PathBuf};
+
+    use anyhow::ensure;
+
+    use crate::{
+        layered_repository::{TENANTS_SEGMENT_NAME, TIMELINES_SEGMENT_NAME},
+        repository::repo_harness::{RepoHarness, TIMELINE_ID},
+    };
+
+    /// Gives a timeline path with pageserver workdir stripped off.
+    pub fn relative_timeline_path(harness: &RepoHarness) -> anyhow::Result<PathBuf> {
+        let timeline_path = harness.timeline_path(&TIMELINE_ID);
+        Ok(timeline_path
+            .strip_prefix(&harness.conf.workdir)?
+            .to_path_buf())
+    }
+
+    /// Creates a path with custom tenant id in one of its segments.
+    /// Useful for emulating paths with wrong ids.
+    pub fn custom_tenant_id_path(
+        path_with_tenant_id: &Path,
+        new_tenant_id: &str,
+    ) -> anyhow::Result<PathBuf> {
+        let mut new_path = PathBuf::new();
+        let mut is_tenant_id = false;
+        let mut tenant_id_replaced = false;
+        for segment in path_with_tenant_id {
+            match segment.to_str() {
+                Some(TENANTS_SEGMENT_NAME) => is_tenant_id = true,
+                Some(_tenant_id_str) if is_tenant_id => {
+                    is_tenant_id = false;
+                    new_path.push(new_tenant_id);
+                    tenant_id_replaced = true;
+                    continue;
+                }
+                _ => {}
+            }
+            new_path.push(segment)
+        }
+
+        ensure!(tenant_id_replaced, "Found no tenant id segment to replace");
+        Ok(new_path)
+    }
+
+    /// Creates a path with custom timeline id in one of its segments.
+    /// Useful for emulating paths with wrong ids.
+    pub fn custom_timeline_id_path(
+        path_with_timeline_id: &Path,
+        new_timeline_id: &str,
+    ) -> anyhow::Result<PathBuf> {
+        let mut new_path = PathBuf::new();
+        let mut is_timeline_id = false;
+        let mut timeline_id_replaced = false;
+        for segment in path_with_timeline_id {
+            match segment.to_str() {
+                Some(TIMELINES_SEGMENT_NAME) => is_timeline_id = true,
+                Some(_timeline_id_str) if is_timeline_id => {
+                    is_timeline_id = false;
+                    new_path.push(new_timeline_id);
+                    timeline_id_replaced = true;
+                    continue;
+                }
+                _ => {}
+            }
+            new_path.push(segment)
+        }
+
+        ensure!(
+            timeline_id_replaced,
+            "Found no timeline id segment to replace"
+        );
+        Ok(new_path)
+    }
+}

pageserver/src/remote_storage/README.md

@@ -0,0 +1,82 @@
+# Non-implementation details
+
+This document describes the current state of the backup system in pageserver, existing limitations and concerns, why some things are done the way they are the future development plans.
+Detailed description on how the synchronization works and how it fits into the rest of the pageserver can be found in the [storage module](./../remote_storage.rs) and its submodules.
+Ideally, this document should disappear after current implementation concerns are mitigated, with the remaining useful knowledge bits moved into rustdocs.
+
+## Approach
+
+Backup functionality is a new component, appeared way after the core DB functionality was implemented.
+Pageserver layer functionality is also quite volatile at the moment, there's a risk its local file management changes over time.
+
+To avoid adding more chaos into that, backup functionality is currently designed as a relatively standalone component, with the majority of its logic placed in a standalone async loop.
+This way, the backups are managed in background, not affecting directly other pageserver parts: this way the backup and restoration process may lag behind, but eventually keep up with the reality. To track that, a set of prometheus metrics is exposed from pageserver.
+
+## What's done
+
+Current implementation
+* provides remote storage wrappers for AWS S3 and local FS
+* uploads layers, frozen by pageserver checkpoint thread
+* downloads and registers layers, found on the remote storage, but missing locally
+
+No good optimisations or performance testing is done, the feature is disabled by default and gets polished over time.
+It's planned to deal with all questions that are currently on and prepare the feature to be enabled by default in cloud environments.
+
+### Peculiarities
+
+As mentioned, the backup component is rather new and under development currently, so not all things are done properly from the start.
+Here's the list of known compromises with comments:
+
+* Remote storage model is the same as the `tenants/` directory contents of the pageserver's local workdir storage.
+This is relatively simple to implement, but may be costly to use in AWS S3: an initial data image contains ~782 relish files and a metadata file, ~31 MB combined.
+AWS charges per API call and for traffic either, layers are expected to be updated frequently, so this model most probably is ineffective.
+Additionally, pageservers might need to migrate images between tenants, which does not improve the situation.
+
+Storage sync API operates images when backing up or restoring a backup, so we're fluent to repack the layer contents the way we want to, which most probably will be done later.
+
+* no proper file comparison
+
+Currently, every layer contains `Lsn` in their name, to map the data it holds against a certain DB state.
+Then the images with same ids and different `Lsn`'s are compared, files are considered equal if their local file paths are equal (for remote files, "local file path" is their download destination).
+No file contents assertion is done currently, but should be.
+AWS S3 returns file checksums during the `list` operation, so that can be used to ensure the backup consistency, but that needs further research and, since current pageserver impl also needs to deal with layer file checksums.
+
+For now, due to this, we consider local workdir files as source of truth, not removing them ever and adjusting remote files instead, if image files mismatch.
+
+* no proper retry management
+
+Now, the storage sync attempts to redo the upload/download operation for the image files that failed.
+No proper task eviction or backpressure is implemented currently: the tasks will stay in the queue forever, reattempting the downloads.
+
+This will be fixed when more details on the file consistency model will be agreed on.
+
+* sad rust-s3 api
+
+rust-s3 is not very pleasant to use:
+1. it returns `anyhow::Result` and it's hard to distinguish "missing file" cases from "no connection" one, for instance
+2. at least one function it its API that we need (`get_object_stream`) has `async` keyword and blocks (!), see details [here](https://github.com/zenithdb/zenith/pull/752#discussion_r728373091)
+3. it's a prerelease library with unclear maintenance status
+4. noisy on debug level
+
+But it's already used in the project, so for now it's reused to avoid bloating the dependency tree.
+Based on previous evaluation, even `rusoto-s3` could be a better choice over this library, but needs further benchmarking.
+
+
+* gc and branches are ignored
+
+So far, we don't consider non-main images and don't adjust the remote storage based on GC thread loop results.
+Only checkpointer loop affects the remote storage.
+
+* more layers should be downloaded on demand
+
+Since we download and load remote layers into pageserver, there's a possibility a need for those layers' ancestors arise.
+Most probably, every downloaded image's ancestor is not present in locally too, but currently there's no logic for downloading such ancestors and their metadata,
+so the pageserver is unable to respond property on requests to such ancestors.
+
+To implement the downloading, more `tenant_mgr` refactoring is needed to properly handle web requests for layers and handle the state changes.
+[Here](https://github.com/zenithdb/zenith/pull/689#issuecomment-931216193) are the details about initial state management updates needed.
+
+* no IT tests
+
+Automated S3 testing is lacking currently, due to no convenient way to enable backups during the tests.
+After it's fixed, benchmark runs should also be carried out to find bottlenecks.

pageserver/src/remote_storage/local_fs.rs

@@ -0,0 +1,574 @@
+//! Local filesystem acting as a remote storage.
+//! Multiple pageservers can use the same "storage" of this kind by using different storage roots.
+//!
+//! This storage used in pageserver tests, but can also be used in cases when a certain persistent
+//! volume is mounted to the local FS.
+
+use std::{
+    ffi::OsStr,
+    future::Future,
+    path::{Path, PathBuf},
+    pin::Pin,
+};
+
+use anyhow::{bail, Context};
+use tokio::{
+    fs,
+    io::{self, AsyncWriteExt},
+};
+use tracing::*;
+
+use crate::layered_repository::metadata::METADATA_FILE_NAME;
+
+use super::{parse_ids_from_path, strip_path_prefix, RemoteFileInfo, RemoteStorage};
+
+pub struct LocalFs {
+    pageserver_workdir: &'static Path,
+    root: PathBuf,
+}
+
+impl LocalFs {
+    /// Attempts to create local FS storage, along with its root directory.
+    pub fn new(root: PathBuf, pageserver_workdir: &'static Path) -> anyhow::Result<Self> {
+        if !root.exists() {
+            std::fs::create_dir_all(&root).with_context(|| {
+                format!(
+                    "Failed to create all directories in the given root path '{}'",
+                    root.display(),
+                )
+            })?;
+        }
+        Ok(Self {
+            pageserver_workdir,
+            root,
+        })
+    }
+
+    fn resolve_in_storage(&self, path: &Path) -> anyhow::Result<PathBuf> {
+        if path.is_relative() {
+            Ok(self.root.join(path))
+        } else if path.starts_with(&self.root) {
+            Ok(path.to_path_buf())
+        } else {
+            bail!(
+                "Path '{}' does not belong to the current storage",
+                path.display()
+            )
+        }
+    }
+}
+
+#[async_trait::async_trait]
+impl RemoteStorage for LocalFs {
+    type StoragePath = PathBuf;
+
+    fn storage_path(&self, local_path: &Path) -> anyhow::Result<Self::StoragePath> {
+        Ok(self.root.join(
+            strip_path_prefix(self.pageserver_workdir, local_path)
+                .context("local path does not belong to this storage")?,
+        ))
+    }
+
+    fn info(&self, storage_path: &Self::StoragePath) -> anyhow::Result<RemoteFileInfo> {
+        let is_metadata =
+            storage_path.file_name().and_then(OsStr::to_str) == Some(METADATA_FILE_NAME);
+        let relative_path = strip_path_prefix(&self.root, storage_path)
+            .context("local path does not belong to this storage")?;
+        let download_destination = self.pageserver_workdir.join(relative_path);
+        let (tenant_id, timeline_id) = parse_ids_from_path(
+            relative_path.iter().filter_map(|segment| segment.to_str()),
+            &relative_path.display(),
+        )?;
+        Ok(RemoteFileInfo {
+            tenant_id,
+            timeline_id,
+            download_destination,
+            is_metadata,
+        })
+    }
+
+    async fn list(&self) -> anyhow::Result<Vec<Self::StoragePath>> {
+        Ok(get_all_files(&self.root).await?.into_iter().collect())
+    }
+
+    async fn upload(
+        &self,
+        mut from: impl io::AsyncRead + Unpin + Send + Sync + 'static,
+        to: &Self::StoragePath,
+    ) -> anyhow::Result<()> {
+        let target_file_path = self.resolve_in_storage(to)?;
+        create_target_directory(&target_file_path).await?;
+        let mut destination = io::BufWriter::new(
+            fs::OpenOptions::new()
+                .write(true)
+                .create(true)
+                .open(&target_file_path)
+                .await
+                .with_context(|| {
+                    format!(
+                        "Failed to open target fs destination at '{}'",
+                        target_file_path.display()
+                    )
+                })?,
+        );
+
+        io::copy(&mut from, &mut destination)
+            .await
+            .context("Failed to upload a file to the local storage")?;
+        destination
+            .flush()
+            .await
+            .context("Failed to upload a file to the local storage")?;
+        Ok(())
+    }
+
+    async fn download(
+        &self,
+        from: &Self::StoragePath,
+        to: &mut (impl io::AsyncWrite + Unpin + Send + Sync),
+    ) -> anyhow::Result<()> {
+        let file_path = self.resolve_in_storage(from)?;
+
+        if file_path.exists() && file_path.is_file() {
+            let mut source = io::BufReader::new(
+                fs::OpenOptions::new()
+                    .read(true)
+                    .open(&file_path)
+                    .await
+                    .with_context(|| {
+                        format!(
+                            "Failed to open source file '{}' to use in the download",
+                            file_path.display()
+                        )
+                    })?,
+            );
+            io::copy(&mut source, to)
+                .await
+                .context("Failed to download a file from the local storage")?;
+            Ok(())
+        } else {
+            bail!(
+                "File '{}' either does not exist or is not a file",
+                file_path.display()
+            )
+        }
+    }
+
+    async fn delete(&self, path: &Self::StoragePath) -> anyhow::Result<()> {
+        let file_path = self.resolve_in_storage(path)?;
+        if file_path.exists() && file_path.is_file() {
+            Ok(fs::remove_file(file_path).await?)
+        } else {
+            bail!(
+                "File '{}' either does not exist or is not a file",
+                file_path.display()
+            )
+        }
+    }
+}
+
+fn get_all_files<'a, P>(
+    directory_path: P,
+) -> Pin<Box<dyn Future<Output = anyhow::Result<Vec<PathBuf>>> + Send + Sync + 'a>>
+where
+    P: AsRef<Path> + Send + Sync + 'a,
+{
+    Box::pin(async move {
+        let directory_path = directory_path.as_ref();
+        if directory_path.exists() {
+            if directory_path.is_dir() {
+                let mut paths = Vec::new();
+                let mut dir_contents = fs::read_dir(directory_path).await?;
+                while let Some(dir_entry) = dir_contents.next_entry().await? {
+                    let file_type = dir_entry.file_type().await?;
+                    let entry_path = dir_entry.path();
+                    if file_type.is_symlink() {
+                        debug!("{:?} us a symlink, skipping", entry_path)
+                    } else if file_type.is_dir() {
+                        paths.extend(get_all_files(entry_path).await?.into_iter())
+                    } else {
+                        paths.push(dir_entry.path());
+                    }
+                }
+                Ok(paths)
+            } else {
+                bail!("Path '{}' is not a directory", directory_path.display())
+            }
+        } else {
+            Ok(Vec::new())
+        }
+    })
+}
+
+async fn create_target_directory(target_file_path: &Path) -> anyhow::Result<()> {
+    let target_dir = match target_file_path.parent() {
+        Some(parent_dir) => parent_dir,
+        None => bail!(
+            "File path '{}' has no parent directory",
+            target_file_path.display()
+        ),
+    };
+    if !target_dir.exists() {
+        fs::create_dir_all(target_dir).await?;
+    }
+    Ok(())
+}
+
+#[cfg(test)]
+mod pure_tests {
+    use crate::{
+        layered_repository::metadata::METADATA_FILE_NAME,
+        remote_storage::test_utils::{
+            custom_tenant_id_path, custom_timeline_id_path, relative_timeline_path,
+        },
+        repository::repo_harness::{RepoHarness, TIMELINE_ID},
+    };
+
+    use super::*;
+
+    #[test]
+    fn storage_path_positive() -> anyhow::Result<()> {
+        let repo_harness = RepoHarness::create("storage_path_positive")?;
+        let storage_root = PathBuf::from("somewhere").join("else");
+        let storage = LocalFs {
+            pageserver_workdir: &repo_harness.conf.workdir,
+            root: storage_root.clone(),
+        };
+
+        let local_path = repo_harness.timeline_path(&TIMELINE_ID).join("file_name");
+        let expected_path = storage_root.join(local_path.strip_prefix(&repo_harness.conf.workdir)?);
+
+        assert_eq!(
+            expected_path,
+            storage.storage_path(&local_path).expect("Matching path should map to storage path normally"),
+            "File paths from pageserver workdir should be stored in local fs storage with the same path they have relative to the workdir"
+        );
+
+        Ok(())
+    }
+
+    #[test]
+    fn storage_path_negatives() -> anyhow::Result<()> {
+        #[track_caller]
+        fn storage_path_error(storage: &LocalFs, mismatching_path: &Path) -> String {
+            match storage.storage_path(mismatching_path) {
+                Ok(wrong_path) => panic!(
+                    "Expected path '{}' to error, but got storage path: {:?}",
+                    mismatching_path.display(),
+                    wrong_path,
+                ),
+                Err(e) => format!("{:?}", e),
+            }
+        }
+
+        let repo_harness = RepoHarness::create("storage_path_negatives")?;
+        let storage_root = PathBuf::from("somewhere").join("else");
+        let storage = LocalFs {
+            pageserver_workdir: &repo_harness.conf.workdir,
+            root: storage_root,
+        };
+
+        let error_string = storage_path_error(&storage, &repo_harness.conf.workdir);
+        assert!(error_string.contains("does not belong to this storage"));
+        assert!(error_string.contains(repo_harness.conf.workdir.to_str().unwrap()));
+
+        let mismatching_path_str = "/something/else";
+        let error_message = storage_path_error(&storage, Path::new(mismatching_path_str));
+        assert!(
+            error_message.contains(mismatching_path_str),
+            "Error should mention wrong path"
+        );
+        assert!(
+            error_message.contains(repo_harness.conf.workdir.to_str().unwrap()),
+            "Error should mention server workdir"
+        );
+        assert!(error_message.contains("does not belong to this storage"));
+
+        Ok(())
+    }
+
+    #[test]
+    fn info_positive() -> anyhow::Result<()> {
+        let repo_harness = RepoHarness::create("info_positive")?;
+        let storage_root = PathBuf::from("somewhere").join("else");
+        let storage = LocalFs {
+            pageserver_workdir: &repo_harness.conf.workdir,
+            root: storage_root.clone(),
+        };
+
+        let name = "not a metadata";
+        let local_path = repo_harness.timeline_path(&TIMELINE_ID).join(name);
+        assert_eq!(
+            RemoteFileInfo {
+                tenant_id: repo_harness.tenant_id,
+                timeline_id: TIMELINE_ID,
+                download_destination: local_path.clone(),
+                is_metadata: false,
+            },
+            storage
+                .info(&storage_root.join(local_path.strip_prefix(&repo_harness.conf.workdir)?))
+                .expect("For a valid input, valid S3 info should be parsed"),
+            "Should be able to parse metadata out of the correctly named remote delta file"
+        );
+
+        let local_metadata_path = repo_harness
+            .timeline_path(&TIMELINE_ID)
+            .join(METADATA_FILE_NAME);
+        let remote_metadata_path = storage.storage_path(&local_metadata_path)?;
+        assert_eq!(
+            RemoteFileInfo {
+                tenant_id: repo_harness.tenant_id,
+                timeline_id: TIMELINE_ID,
+                download_destination: local_metadata_path,
+                is_metadata: true,
+            },
+            storage
+                .info(&remote_metadata_path)
+                .expect("For a valid input, valid S3 info should be parsed"),
+            "Should be able to parse metadata out of the correctly named remote metadata file"
+        );
+
+        Ok(())
+    }
+
+    #[test]
+    fn info_negatives() -> anyhow::Result<()> {
+        #[track_caller]
+        #[allow(clippy::ptr_arg)] // have to use &PathBuf due to `storage.info` parameter requirements
+        fn storage_info_error(storage: &LocalFs, storage_path: &PathBuf) -> String {
+            match storage.info(storage_path) {
+                Ok(wrong_info) => panic!(
+                    "Expected storage path input {:?} to cause an error, but got file info: {:?}",
+                    storage_path, wrong_info,
+                ),
+                Err(e) => format!("{:?}", e),
+            }
+        }
+
+        let repo_harness = RepoHarness::create("info_negatives")?;
+        let storage_root = PathBuf::from("somewhere").join("else");
+        let storage = LocalFs {
+            pageserver_workdir: &repo_harness.conf.workdir,
+            root: storage_root.clone(),
+        };
+
+        let totally_wrong_path = "wrong_wrong_wrong";
+        let error_message = storage_info_error(&storage, &PathBuf::from(totally_wrong_path));
+        assert!(error_message.contains(totally_wrong_path));
+
+        let relative_timeline_path = relative_timeline_path(&repo_harness)?;
+
+        let relative_file_path = custom_tenant_id_path(&relative_timeline_path, "wrong_tenant_id")?
+            .join("wrong_tenant_id_name");
+        let wrong_tenant_id_path = storage_root.join(&relative_file_path);
+        let error_message = storage_info_error(&storage, &wrong_tenant_id_path);
+        assert!(
+            error_message.contains(relative_file_path.to_str().unwrap()),
+            "Error message '{}' does not contain the expected substring",
+            error_message
+        );
+
+        let relative_file_path =
+            custom_timeline_id_path(&relative_timeline_path, "wrong_timeline_id")?
+                .join("wrong_timeline_id_name");
+        let wrong_timeline_id_path = storage_root.join(&relative_file_path);
+        let error_message = storage_info_error(&storage, &wrong_timeline_id_path);
+        assert!(
+            error_message.contains(relative_file_path.to_str().unwrap()),
+            "Error message '{}' does not contain the expected substring",
+            error_message
+        );
+
+        Ok(())
+    }
+
+    #[test]
+    fn download_destination_matches_original_path() -> anyhow::Result<()> {
+        let repo_harness = RepoHarness::create("download_destination_matches_original_path")?;
+        let original_path = repo_harness.timeline_path(&TIMELINE_ID).join("some name");
+
+        let storage_root = PathBuf::from("somewhere").join("else");
+        let dummy_storage = LocalFs {
+            pageserver_workdir: &repo_harness.conf.workdir,
+            root: storage_root,
+        };
+
+        let storage_path = dummy_storage.storage_path(&original_path)?;
+        let download_destination = dummy_storage.info(&storage_path)?.download_destination;
+
+        assert_eq!(
+            original_path, download_destination,
+            "'original path -> storage path -> matching fs path' transformation should produce the same path as the input one for the correct path"
+        );
+
+        Ok(())
+    }
+}
+
+#[cfg(test)]
+mod fs_tests {
+    use super::*;
+    use crate::{
+        remote_storage::test_utils::relative_timeline_path, repository::repo_harness::RepoHarness,
+    };
+
+    use std::io::Write;
+    use tempfile::tempdir;
+
+    #[tokio::test]
+    async fn upload_file() -> anyhow::Result<()> {
+        let repo_harness = RepoHarness::create("upload_file")?;
+        let storage = create_storage()?;
+
+        let source = create_file_for_upload(
+            &storage.pageserver_workdir.join("whatever"),
+            "whatever_contents",
+        )
+        .await?;
+        let target_path = PathBuf::from("/").join("somewhere").join("else");
+        match storage.upload(source, &target_path).await {
+            Ok(()) => panic!("Should not allow storing files with wrong target path"),
+            Err(e) => {
+                let message = format!("{:?}", e);
+                assert!(message.contains(&target_path.display().to_string()));
+                assert!(message.contains("does not belong to the current storage"));
+            }
+        }
+        assert!(storage.list().await?.is_empty());
+
+        let target_path_1 = upload_dummy_file(&repo_harness, &storage, "upload_1").await?;
+        assert_eq!(
+            storage.list().await?,
+            vec![target_path_1.clone()],
+            "Should list a single file after first upload"
+        );
+
+        let target_path_2 = upload_dummy_file(&repo_harness, &storage, "upload_2").await?;
+        assert_eq!(
+            list_files_sorted(&storage).await?,
+            vec![target_path_1.clone(), target_path_2.clone()],
+            "Should list a two different files after second upload"
+        );
+
+        // match storage.upload_file(&mut source, &target_path_1).await {
+        //     Ok(()) => panic!("Should not allow reuploading storage files"),
+        //     Err(e) => {
+        //         let message = format!("{:?}", e);
+        //         assert!(message.contains(&target_path_1.display().to_string()));
+        //         assert!(message.contains("File exists"));
+        //     }
+        // }
+        assert_eq!(
+            list_files_sorted(&storage).await?,
+            vec![target_path_1, target_path_2],
+            "Should list a two different files after all upload attempts"
+        );
+
+        Ok(())
+    }
+
+    fn create_storage() -> anyhow::Result<LocalFs> {
+        let pageserver_workdir = Box::leak(Box::new(tempdir()?.path().to_owned()));
+        let storage = LocalFs::new(tempdir()?.path().to_owned(), pageserver_workdir)?;
+        Ok(storage)
+    }
+
+    #[tokio::test]
+    async fn download_file() -> anyhow::Result<()> {
+        let repo_harness = RepoHarness::create("download_file")?;
+        let storage = create_storage()?;
+        let upload_name = "upload_1";
+        let upload_target = upload_dummy_file(&repo_harness, &storage, upload_name).await?;
+
+        let mut content_bytes = io::BufWriter::new(std::io::Cursor::new(Vec::new()));
+        storage.download(&upload_target, &mut content_bytes).await?;
+        content_bytes.flush().await?;
+
+        let contents = String::from_utf8(content_bytes.into_inner().into_inner())?;
+        assert_eq!(
+            dummy_contents(upload_name),
+            contents,
+            "We should upload and download the same contents"
+        );
+
+        let non_existing_path = PathBuf::from("somewhere").join("else");
+        match storage.download(&non_existing_path, &mut io::sink()).await {
+            Ok(_) => panic!("Should not allow downloading non-existing storage files"),
+            Err(e) => {
+                let error_string = e.to_string();
+                assert!(error_string.contains("does not exist"));
+                assert!(error_string.contains(&non_existing_path.display().to_string()));
+            }
+        }
+        Ok(())
+    }
+
+    #[tokio::test]
+    async fn delete_file() -> anyhow::Result<()> {
+        let repo_harness = RepoHarness::create("delete_file")?;
+        let storage = create_storage()?;
+        let upload_name = "upload_1";
+        let upload_target = upload_dummy_file(&repo_harness, &storage, upload_name).await?;
+
+        storage.delete(&upload_target).await?;
+        assert!(storage.list().await?.is_empty());
+
+        match storage.delete(&upload_target).await {
+            Ok(()) => panic!("Should not allow deleting non-existing storage files"),
+            Err(e) => {
+                let error_string = e.to_string();
+                assert!(error_string.contains("does not exist"));
+                assert!(error_string.contains(&upload_target.display().to_string()));
+            }
+        }
+        Ok(())
+    }
+
+    async fn upload_dummy_file(
+        harness: &RepoHarness,
+        storage: &LocalFs,
+        name: &str,
+    ) -> anyhow::Result<PathBuf> {
+        let storage_path = storage
+            .root
+            .join(relative_timeline_path(harness)?)
+            .join(name);
+        storage
+            .upload(
+                create_file_for_upload(
+                    &storage.pageserver_workdir.join(name),
+                    &dummy_contents(name),
+                )
+                .await?,
+                &storage_path,
+            )
+            .await?;
+        Ok(storage_path)
+    }
+
+    async fn create_file_for_upload(
+        path: &Path,
+        contents: &str,
+    ) -> anyhow::Result<io::BufReader<fs::File>> {
+        std::fs::create_dir_all(path.parent().unwrap())?;
+        let mut file_for_writing = std::fs::OpenOptions::new()
+            .write(true)
+            .create_new(true)
+            .open(path)?;
+        write!(file_for_writing, "{}", contents)?;
+        drop(file_for_writing);
+        Ok(io::BufReader::new(
+            fs::OpenOptions::new().read(true).open(&path).await?,
+        ))
+    }
+
+    fn dummy_contents(name: &str) -> String {
+        format!("contents for {}", name)
+    }
+
+    async fn list_files_sorted(storage: &LocalFs) -> anyhow::Result<Vec<PathBuf>> {
+        let mut files = storage.list().await?;
+        files.sort();
+        Ok(files)
+    }
+}

pageserver/src/remote_storage/rust_s3.rs

@@ -0,0 +1,401 @@
+//! AWS S3 storage wrapper around `rust_s3` library.
+//! Currently does not allow multiple pageservers to use the same bucket concurrently: objects are
+//! placed in the root of the bucket.
+
+use std::path::{Path, PathBuf};
+
+use anyhow::Context;
+use s3::{bucket::Bucket, creds::Credentials, region::Region};
+use tokio::io::{self, AsyncWriteExt};
+
+use crate::{
+    layered_repository::metadata::METADATA_FILE_NAME,
+    remote_storage::{parse_ids_from_path, strip_path_prefix, RemoteFileInfo, RemoteStorage},
+    S3Config,
+};
+
+const S3_FILE_SEPARATOR: char = '/';
+
+#[derive(Debug, Eq, PartialEq)]
+pub struct S3ObjectKey(String);
+
+impl S3ObjectKey {
+    fn key(&self) -> &str {
+        &self.0
+    }
+
+    fn download_destination(&self, pageserver_workdir: &Path) -> PathBuf {
+        pageserver_workdir.join(self.0.split(S3_FILE_SEPARATOR).collect::<PathBuf>())
+    }
+}
+
+/// AWS S3 storage.
+pub struct S3 {
+    pageserver_workdir: &'static Path,
+    bucket: Bucket,
+}
+
+impl S3 {
+    /// Creates the storage, errors if incorrect AWS S3 configuration provided.
+    pub fn new(aws_config: &S3Config, pageserver_workdir: &'static Path) -> anyhow::Result<Self> {
+        let region = aws_config
+            .bucket_region
+            .parse::<Region>()
+            .context("Failed to parse the s3 region from config")?;
+        let credentials = Credentials::new(
+            aws_config.access_key_id.as_deref(),
+            aws_config.secret_access_key.as_deref(),
+            None,
+            None,
+            None,
+        )
+        .context("Failed to create the s3 credentials")?;
+        Ok(Self {
+            bucket: Bucket::new_with_path_style(
+                aws_config.bucket_name.as_str(),
+                region,
+                credentials,
+            )
+            .context("Failed to create the s3 bucket")?,
+            pageserver_workdir,
+        })
+    }
+}
+
+#[async_trait::async_trait]
+impl RemoteStorage for S3 {
+    type StoragePath = S3ObjectKey;
+
+    fn storage_path(&self, local_path: &Path) -> anyhow::Result<Self::StoragePath> {
+        let relative_path = strip_path_prefix(self.pageserver_workdir, local_path)?;
+        let mut key = String::new();
+        for segment in relative_path {
+            key.push(S3_FILE_SEPARATOR);
+            key.push_str(&segment.to_string_lossy());
+        }
+        Ok(S3ObjectKey(key))
+    }
+
+    fn info(&self, storage_path: &Self::StoragePath) -> anyhow::Result<RemoteFileInfo> {
+        let storage_path_key = &storage_path.0;
+        let is_metadata =
+            storage_path_key.ends_with(&format!("{}{}", S3_FILE_SEPARATOR, METADATA_FILE_NAME));
+        let download_destination = storage_path.download_destination(self.pageserver_workdir);
+        let (tenant_id, timeline_id) =
+            parse_ids_from_path(storage_path_key.split(S3_FILE_SEPARATOR), storage_path_key)?;
+        Ok(RemoteFileInfo {
+            tenant_id,
+            timeline_id,
+            download_destination,
+            is_metadata,
+        })
+    }
+
+    async fn list(&self) -> anyhow::Result<Vec<Self::StoragePath>> {
+        let list_response = self
+            .bucket
+            .list(String::new(), None)
+            .await
+            .context("Failed to list s3 objects")?;
+
+        Ok(list_response
+            .into_iter()
+            .flat_map(|response| response.contents)
+            .map(|s3_object| S3ObjectKey(s3_object.key))
+            .collect())
+    }
+
+    async fn upload(
+        &self,
+        mut from: impl io::AsyncRead + Unpin + Send + Sync + 'static,
+        to: &Self::StoragePath,
+    ) -> anyhow::Result<()> {
+        let mut upload_contents = io::BufWriter::new(std::io::Cursor::new(Vec::new()));
+        io::copy(&mut from, &mut upload_contents)
+            .await
+            .context("Failed to read the upload contents")?;
+        upload_contents
+            .flush()
+            .await
+            .context("Failed to read the upload contents")?;
+        let upload_contents = upload_contents.into_inner().into_inner();
+
+        let (_, code) = self
+            .bucket
+            .put_object(to.key(), &upload_contents)
+            .await
+            .with_context(|| format!("Failed to create s3 object with key {}", to.key()))?;
+        if code != 200 {
+            Err(anyhow::format_err!(
+                "Received non-200 exit code during creating object with key '{}', code: {}",
+                to.key(),
+                code
+            ))
+        } else {
+            Ok(())
+        }
+    }
+
+    async fn download(
+        &self,
+        from: &Self::StoragePath,
+        to: &mut (impl io::AsyncWrite + Unpin + Send + Sync),
+    ) -> anyhow::Result<()> {
+        let (data, code) = self
+            .bucket
+            .get_object(from.key())
+            .await
+            .with_context(|| format!("Failed to download s3 object with key {}", from.key()))?;
+        if code != 200 {
+            Err(anyhow::format_err!(
+                "Received non-200 exit code during downloading object from directory, code: {}",
+                code
+            ))
+        } else {
+            io::copy(&mut io::BufReader::new(data.as_slice()), to)
+                .await
+                .context("Failed to write downloaded data into the destination buffer")?;
+            Ok(())
+        }
+    }
+
+    async fn delete(&self, path: &Self::StoragePath) -> anyhow::Result<()> {
+        let (_, code) = self
+            .bucket
+            .delete_object(path.key())
+            .await
+            .with_context(|| format!("Failed to delete s3 object with key {}", path.key()))?;
+        if code != 204 {
+            Err(anyhow::format_err!(
+                "Received non-204 exit code during deleting object with key '{}', code: {}",
+                path.key(),
+                code
+            ))
+        } else {
+            Ok(())
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::{
+        remote_storage::test_utils::{
+            custom_tenant_id_path, custom_timeline_id_path, relative_timeline_path,
+        },
+        repository::repo_harness::{RepoHarness, TIMELINE_ID},
+    };
+
+    use super::*;
+
+    #[test]
+    fn download_destination() -> anyhow::Result<()> {
+        let repo_harness = RepoHarness::create("download_destination")?;
+
+        let local_path = repo_harness.timeline_path(&TIMELINE_ID).join("test_name");
+        let relative_path = local_path.strip_prefix(&repo_harness.conf.workdir)?;
+
+        let key = S3ObjectKey(format!(
+            "{}{}",
+            S3_FILE_SEPARATOR,
+            relative_path
+                .iter()
+                .map(|segment| segment.to_str().unwrap())
+                .collect::<Vec<_>>()
+                .join(&S3_FILE_SEPARATOR.to_string()),
+        ));
+
+        assert_eq!(
+            local_path,
+            key.download_destination(&repo_harness.conf.workdir),
+            "Download destination should consist of s3 path joined with the pageserver workdir prefix"
+        );
+
+        Ok(())
+    }
+
+    #[test]
+    fn storage_path_positive() -> anyhow::Result<()> {
+        let repo_harness = RepoHarness::create("storage_path_positive")?;
+
+        let segment_1 = "matching";
+        let segment_2 = "file";
+        let local_path = &repo_harness.conf.workdir.join(segment_1).join(segment_2);
+        let expected_key = S3ObjectKey(format!(
+            "{SEPARATOR}{}{SEPARATOR}{}",
+            segment_1,
+            segment_2,
+            SEPARATOR = S3_FILE_SEPARATOR,
+        ));
+
+        let actual_key = dummy_storage(&repo_harness.conf.workdir)
+            .storage_path(local_path)
+            .expect("Matching path should map to S3 path normally");
+        assert_eq!(
+            expected_key,
+            actual_key,
+            "S3 key from the matching path should contain all segments after the workspace prefix, separated with S3 separator"
+        );
+
+        Ok(())
+    }
+
+    #[test]
+    fn storage_path_negatives() -> anyhow::Result<()> {
+        #[track_caller]
+        fn storage_path_error(storage: &S3, mismatching_path: &Path) -> String {
+            match storage.storage_path(mismatching_path) {
+                Ok(wrong_key) => panic!(
+                    "Expected path '{}' to error, but got S3 key: {:?}",
+                    mismatching_path.display(),
+                    wrong_key,
+                ),
+                Err(e) => e.to_string(),
+            }
+        }
+
+        let repo_harness = RepoHarness::create("storage_path_negatives")?;
+        let storage = dummy_storage(&repo_harness.conf.workdir);
+
+        let error_message = storage_path_error(&storage, &repo_harness.conf.workdir);
+        assert!(
+            error_message.contains("Prefix and the path are equal"),
+            "Message '{}' does not contain the required string",
+            error_message
+        );
+
+        let mismatching_path = PathBuf::from("somewhere").join("else");
+        let error_message = storage_path_error(&storage, &mismatching_path);
+        assert!(
+            error_message.contains(mismatching_path.to_str().unwrap()),
+            "Error should mention wrong path"
+        );
+        assert!(
+            error_message.contains(repo_harness.conf.workdir.to_str().unwrap()),
+            "Error should mention server workdir"
+        );
+        assert!(
+            error_message.contains("is not prefixed with"),
+            "Message '{}' does not contain a required string",
+            error_message
+        );
+
+        Ok(())
+    }
+
+    #[test]
+    fn info_positive() -> anyhow::Result<()> {
+        let repo_harness = RepoHarness::create("info_positive")?;
+        let storage = dummy_storage(&repo_harness.conf.workdir);
+        let relative_timeline_path = relative_timeline_path(&repo_harness)?;
+
+        let s3_key = create_s3_key(&relative_timeline_path.join("not a metadata"));
+        assert_eq!(
+            RemoteFileInfo {
+                tenant_id: repo_harness.tenant_id,
+                timeline_id: TIMELINE_ID,
+                download_destination: s3_key.download_destination(&repo_harness.conf.workdir),
+                is_metadata: false,
+            },
+            storage
+                .info(&s3_key)
+                .expect("For a valid input, valid S3 info should be parsed"),
+            "Should be able to parse metadata out of the correctly named remote delta file"
+        );
+
+        let s3_key = create_s3_key(&relative_timeline_path.join(METADATA_FILE_NAME));
+        assert_eq!(
+            RemoteFileInfo {
+                tenant_id: repo_harness.tenant_id,
+                timeline_id: TIMELINE_ID,
+                download_destination: s3_key.download_destination(&repo_harness.conf.workdir),
+                is_metadata: true,
+            },
+            storage
+                .info(&s3_key)
+                .expect("For a valid input, valid S3 info should be parsed"),
+            "Should be able to parse metadata out of the correctly named remote metadata file"
+        );
+
+        Ok(())
+    }
+
+    #[test]
+    fn info_negatives() -> anyhow::Result<()> {
+        #[track_caller]
+        fn storage_info_error(storage: &S3, s3_key: &S3ObjectKey) -> String {
+            match storage.info(s3_key) {
+                Ok(wrong_info) => panic!(
+                    "Expected key {:?} to error, but got file info: {:?}",
+                    s3_key, wrong_info,
+                ),
+                Err(e) => e.to_string(),
+            }
+        }
+
+        let repo_harness = RepoHarness::create("info_negatives")?;
+        let storage = dummy_storage(&repo_harness.conf.workdir);
+        let relative_timeline_path = relative_timeline_path(&repo_harness)?;
+
+        let totally_wrong_path = "wrong_wrong_wrong";
+        let error_message =
+            storage_info_error(&storage, &S3ObjectKey(totally_wrong_path.to_string()));
+        assert!(error_message.contains(totally_wrong_path));
+
+        let wrong_tenant_id = create_s3_key(
+            &custom_tenant_id_path(&relative_timeline_path, "wrong_tenant_id")?.join("name"),
+        );
+        let error_message = storage_info_error(&storage, &wrong_tenant_id);
+        assert!(error_message.contains(&wrong_tenant_id.0));
+
+        let wrong_timeline_id = create_s3_key(
+            &custom_timeline_id_path(&relative_timeline_path, "wrong_timeline_id")?.join("name"),
+        );
+        let error_message = storage_info_error(&storage, &wrong_timeline_id);
+        assert!(error_message.contains(&wrong_timeline_id.0));
+
+        Ok(())
+    }
+
+    #[test]
+    fn download_destination_matches_original_path() -> anyhow::Result<()> {
+        let repo_harness = RepoHarness::create("download_destination_matches_original_path")?;
+        let original_path = repo_harness.timeline_path(&TIMELINE_ID).join("some name");
+
+        let dummy_storage = dummy_storage(&repo_harness.conf.workdir);
+
+        let key = dummy_storage.storage_path(&original_path)?;
+        let download_destination = dummy_storage.info(&key)?.download_destination;
+
+        assert_eq!(
+            original_path, download_destination,
+            "'original path -> storage key -> matching fs path' transformation should produce the same path as the input one for the correct path"
+        );
+
+        Ok(())
+    }
+
+    fn dummy_storage(pageserver_workdir: &'static Path) -> S3 {
+        S3 {
+            pageserver_workdir,
+            bucket: Bucket::new(
+                "dummy-bucket",
+                "us-east-1".parse().unwrap(),
+                Credentials::anonymous().unwrap(),
+            )
+            .unwrap(),
+        }
+    }
+
+    fn create_s3_key(relative_file_path: &Path) -> S3ObjectKey {
+        S3ObjectKey(
+            relative_file_path
+                .iter()
+                .fold(String::new(), |mut path_string, segment| {
+                    path_string.push(S3_FILE_SEPARATOR);
+                    path_string.push_str(segment.to_str().unwrap());
+                    path_string
+                }),
+        )
+    }
+}

pageserver/src/restore_local_repo.rs

@@ -2,58 +2,54 @@
 //! Import data and WAL from a PostgreSQL data directory and WAL segments into
 //! zenith Timeline.
 //!
-use log::*;
+use postgres_ffi::nonrelfile_utils::clogpage_precedes;
+use postgres_ffi::nonrelfile_utils::slru_may_delete_clogsegment;
 use std::cmp::min;
 use std::fs;
 use std::fs::File;
-use std::io::Read;
-use std::io::Seek;
-use std::io::SeekFrom;
+use std::io::{Read, Seek, SeekFrom};
 use std::path::{Path, PathBuf};
 
-use anyhow::Result;
+use anyhow::{anyhow, bail, Result};
 use bytes::{Buf, Bytes};
+use tracing::*;
 
 use crate::relish::*;
 use crate::repository::*;
 use crate::waldecoder::*;
+use postgres_ffi::nonrelfile_utils::mx_offset_to_member_segment;
 use postgres_ffi::relfile_utils::*;
 use postgres_ffi::xlog_utils::*;
+use postgres_ffi::Oid;
 use postgres_ffi::{pg_constants, CheckPoint, ControlFileData};
-use postgres_ffi::{Oid, TransactionId};
 use zenith_utils::lsn::Lsn;
 
 const MAX_MBR_BLKNO: u32 =
     pg_constants::MAX_MULTIXACT_ID / pg_constants::MULTIXACT_MEMBERS_PER_PAGE as u32;
 
-const ZERO_PAGE: Bytes = Bytes::from_static(&[0u8; 8192]);
+static ZERO_PAGE: Bytes = Bytes::from_static(&[0u8; 8192]);
 
 ///
 /// Import all relation data pages from local disk into the repository.
 ///
 pub fn import_timeline_from_postgres_datadir(
     path: &Path,
-    timeline: &dyn Timeline,
+    writer: &dyn TimelineWriter,
     lsn: Lsn,
 ) -> Result<()> {
+    let mut pg_control: Option<ControlFileData> = None;
+
     // Scan 'global'
     for direntry in fs::read_dir(path.join("global"))? {
         let direntry = direntry?;
         match direntry.file_name().to_str() {
             None => continue,
 
-            // These special files appear in the snapshot, but are not needed by the page server
             Some("pg_control") => {
-                import_nonrel_file(timeline, lsn, RelishTag::ControlFile, &direntry.path())?;
-                // Extract checkpoint record from pg_control and store is as separate object
-                let pg_control_bytes =
-                    timeline.get_page_at_lsn_nowait(RelishTag::ControlFile, 0, lsn)?;
-                let pg_control = ControlFileData::decode(&pg_control_bytes)?;
-                let checkpoint_bytes = pg_control.checkPointCopy.encode();
-                timeline.put_page_image(RelishTag::Checkpoint, 0, lsn, checkpoint_bytes, false)?;
+                pg_control = Some(import_control_file(writer, lsn, &direntry.path())?);
             }
             Some("pg_filenode.map") => import_nonrel_file(
-                timeline,
+                writer,
                 lsn,
                 RelishTag::FileNodeMap {
                     spcnode: pg_constants::GLOBALTABLESPACE_OID,
@@ -65,7 +61,7 @@ pub fn import_timeline_from_postgres_datadir(
             // Load any relation files into the page server
             _ => import_relfile(
                 &direntry.path(),
-                timeline,
+                writer,
                 lsn,
                 pg_constants::GLOBALTABLESPACE_OID,
                 0,
@@ -90,10 +86,9 @@ pub fn import_timeline_from_postgres_datadir(
             match direntry.file_name().to_str() {
                 None => continue,
 
-                // These special files appear in the snapshot, but are not needed by the page server
                 Some("PG_VERSION") => continue,
                 Some("pg_filenode.map") => import_nonrel_file(
-                    timeline,
+                    writer,
                     lsn,
                     RelishTag::FileNodeMap {
                         spcnode: pg_constants::DEFAULTTABLESPACE_OID,
@@ -105,7 +100,7 @@ pub fn import_timeline_from_postgres_datadir(
                 // Load any relation files into the page server
                 _ => import_relfile(
                     &direntry.path(),
-                    timeline,
+                    writer,
                     lsn,
                     pg_constants::DEFAULTTABLESPACE_OID,
                     dboid,
@@ -115,25 +110,36 @@ pub fn import_timeline_from_postgres_datadir(
     }
     for entry in fs::read_dir(path.join("pg_xact"))? {
         let entry = entry?;
-        import_slru_file(timeline, lsn, SlruKind::Clog, &entry.path())?;
+        import_slru_file(writer, lsn, SlruKind::Clog, &entry.path())?;
     }
     for entry in fs::read_dir(path.join("pg_multixact").join("members"))? {
         let entry = entry?;
-        import_slru_file(timeline, lsn, SlruKind::MultiXactMembers, &entry.path())?;
+        import_slru_file(writer, lsn, SlruKind::MultiXactMembers, &entry.path())?;
     }
     for entry in fs::read_dir(path.join("pg_multixact").join("offsets"))? {
         let entry = entry?;
-        import_slru_file(timeline, lsn, SlruKind::MultiXactOffsets, &entry.path())?;
+        import_slru_file(writer, lsn, SlruKind::MultiXactOffsets, &entry.path())?;
     }
     for entry in fs::read_dir(path.join("pg_twophase"))? {
         let entry = entry?;
-        let xid = u32::from_str_radix(&entry.path().to_str().unwrap(), 16)?;
-        import_nonrel_file(timeline, lsn, RelishTag::TwoPhase { xid }, &entry.path())?;
+        let xid = u32::from_str_radix(entry.path().to_str().unwrap(), 16)?;
+        import_nonrel_file(writer, lsn, RelishTag::TwoPhase { xid }, &entry.path())?;
     }
     // TODO: Scan pg_tblspc
 
-    timeline.advance_last_valid_lsn(lsn);
-    timeline.checkpoint()?;
+    writer.advance_last_record_lsn(lsn);
+
+    // Import WAL. This is needed even when starting from a shutdown checkpoint, because
+    // this reads the checkpoint record itself, advancing the tip of the timeline to
+    // *after* the checkpoint record. And crucially, it initializes the 'prev_lsn'
+    let pg_control = pg_control.ok_or_else(|| anyhow!("pg_control file not found"))?;
+    import_wal(
+        &path.join("pg_wal"),
+        writer,
+        Lsn(pg_control.checkPointCopy.redo),
+        lsn,
+        &mut pg_control.checkPointCopy.clone(),
+    )?;
 
     Ok(())
 }
@@ -141,16 +147,17 @@ pub fn import_timeline_from_postgres_datadir(
 // subroutine of import_timeline_from_postgres_datadir(), to load one relation file.
 fn import_relfile(
     path: &Path,
-    timeline: &dyn Timeline,
+    timeline: &dyn TimelineWriter,
     lsn: Lsn,
     spcoid: Oid,
     dboid: Oid,
 ) -> Result<()> {
     // Does it look like a relation file?
+    trace!("importing rel file {}", path.display());
 
     let p = parse_relfilename(path.file_name().unwrap().to_str().unwrap());
     if let Err(e) = p {
-        warn!("unrecognized file in snapshot: {:?} ({})", path, e);
+        warn!("unrecognized file in postgres datadir: {:?} ({})", path, e);
         return Err(e.into());
     }
     let (relnode, forknum, segno) = p.unwrap();
@@ -170,19 +177,18 @@ fn import_relfile(
                     forknum,
                 };
                 let tag = RelishTag::Relation(rel);
-                timeline.put_page_image(tag, blknum, lsn, Bytes::copy_from_slice(&buf), true)?;
+                timeline.put_page_image(tag, blknum, lsn, Bytes::copy_from_slice(&buf))?;
             }
 
             // TODO: UnexpectedEof is expected
-            Err(e) => match e.kind() {
+            Err(err) => match err.kind() {
                 std::io::ErrorKind::UnexpectedEof => {
                     // reached EOF. That's expected.
                     // FIXME: maybe check that we read the full length of the file?
                     break;
                 }
                 _ => {
-                    error!("error reading file: {:?} ({})", path, e);
-                    break;
+                    bail!("error reading file {}: {:#}", path.display(), err);
                 }
             },
         };
@@ -199,7 +205,7 @@ fn import_relfile(
 /// are just slurped into the repository as one blob.
 ///
 fn import_nonrel_file(
-    timeline: &dyn Timeline,
+    timeline: &dyn TimelineWriter,
     lsn: Lsn,
     tag: RelishTag,
     path: &Path,
@@ -209,22 +215,60 @@ fn import_nonrel_file(
     // read the whole file
     file.read_to_end(&mut buffer)?;
 
-    info!("importing non-rel file {}", path.display());
+    trace!("importing non-rel file {}", path.display());
 
-    timeline.put_page_image(tag, 0, lsn, Bytes::copy_from_slice(&buffer[..]), false)?;
+    timeline.put_page_image(tag, 0, lsn, Bytes::copy_from_slice(&buffer[..]))?;
     Ok(())
 }
 
+///
+/// Import pg_control file into the repository.
+///
+/// The control file is imported as is, but we also extract the checkpoint record
+/// from it and store it separated.
+fn import_control_file(
+    timeline: &dyn TimelineWriter,
+    lsn: Lsn,
+    path: &Path,
+) -> Result<ControlFileData> {
+    let mut file = File::open(path)?;
+    let mut buffer = Vec::new();
+    // read the whole file
+    file.read_to_end(&mut buffer)?;
+
+    trace!("importing control file {}", path.display());
+
+    // Import it as ControlFile
+    timeline.put_page_image(
+        RelishTag::ControlFile,
+        0,
+        lsn,
+        Bytes::copy_from_slice(&buffer[..]),
+    )?;
+
+    // Extract the checkpoint record and import it separately.
+    let pg_control = ControlFileData::decode(&buffer)?;
+    let checkpoint_bytes = pg_control.checkPointCopy.encode();
+    timeline.put_page_image(RelishTag::Checkpoint, 0, lsn, checkpoint_bytes)?;
+
+    Ok(pg_control)
+}
+
 ///
 /// Import an SLRU segment file
 ///
-fn import_slru_file(timeline: &dyn Timeline, lsn: Lsn, slru: SlruKind, path: &Path) -> Result<()> {
+fn import_slru_file(
+    timeline: &dyn TimelineWriter,
+    lsn: Lsn,
+    slru: SlruKind,
+    path: &Path,
+) -> Result<()> {
     // Does it look like an SLRU file?
     let mut file = File::open(path)?;
     let mut buf: [u8; 8192] = [0u8; 8192];
     let segno = u32::from_str_radix(path.file_name().unwrap().to_str().unwrap(), 16)?;
 
-    info!("importing slru file {}", path.display());
+    trace!("importing slru file {}", path.display());
 
     let mut rpageno = 0;
     loop {
@@ -236,20 +280,18 @@ fn import_slru_file(timeline: &dyn Timeline, lsn: Lsn, slru: SlruKind, path: &Pa
                     rpageno,
                     lsn,
                     Bytes::copy_from_slice(&buf),
-                    true,
                 )?;
             }
 
             // TODO: UnexpectedEof is expected
-            Err(e) => match e.kind() {
+            Err(err) => match err.kind() {
                 std::io::ErrorKind::UnexpectedEof => {
                     // reached EOF. That's expected.
                     // FIXME: maybe check that we read the full length of the file?
                     break;
                 }
                 _ => {
-                    error!("error reading file: {:?} ({})", path, e);
-                    break;
+                    bail!("error reading file {}: {:#}", path.display(), err);
                 }
             },
         };
@@ -261,24 +303,27 @@ fn import_slru_file(timeline: &dyn Timeline, lsn: Lsn, slru: SlruKind, path: &Pa
     Ok(())
 }
 
-/// Scan PostgreSQL WAL files in given directory
-/// and load all records >= 'startpoint' into the repository.
-pub fn import_timeline_wal(walpath: &Path, timeline: &dyn Timeline, startpoint: Lsn) -> Result<()> {
-    let mut waldecoder = WalStreamDecoder::new(startpoint, true);
+/// Scan PostgreSQL WAL files in given directory and load all records between
+/// 'startpoint' and 'endpoint' into the repository.
+fn import_wal(
+    walpath: &Path,
+    timeline: &dyn TimelineWriter,
+    startpoint: Lsn,
+    endpoint: Lsn,
+    checkpoint: &mut CheckPoint,
+) -> Result<()> {
+    let mut waldecoder = WalStreamDecoder::new(startpoint);
 
     let mut segno = startpoint.segment_number(pg_constants::WAL_SEGMENT_SIZE);
     let mut offset = startpoint.segment_offset(pg_constants::WAL_SEGMENT_SIZE);
     let mut last_lsn = startpoint;
 
-    let checkpoint_bytes = timeline.get_page_at_lsn_nowait(RelishTag::Checkpoint, 0, startpoint)?;
-    let mut checkpoint = CheckPoint::decode(&checkpoint_bytes)?;
-
-    loop {
+    while last_lsn <= endpoint {
         // FIXME: assume postgresql tli 1 for now
         let filename = XLogFileName(1, segno, pg_constants::WAL_SEGMENT_SIZE);
         let mut buf = Vec::new();
 
-        //Read local file
+        // Read local file
         let mut path = walpath.join(&filename);
 
         // It could be as .partial
@@ -287,13 +332,7 @@ pub fn import_timeline_wal(walpath: &Path, timeline: &dyn Timeline, startpoint:
         }
 
         // Slurp the WAL file
-        let open_result = File::open(&path);
-        if let Err(e) = &open_result {
-            if e.kind() == std::io::ErrorKind::NotFound {
-                break;
-            }
-        }
-        let mut file = open_result?;
+        let mut file = File::open(&path)?;
 
         if offset > 0 {
             file.seek(SeekFrom::Start(offset as u64))?;
@@ -308,36 +347,57 @@ pub fn import_timeline_wal(walpath: &Path, timeline: &dyn Timeline, startpoint:
         waldecoder.feed_bytes(&buf);
 
         let mut nrecords = 0;
-        loop {
-            let rec = waldecoder.poll_decode();
-            if rec.is_err() {
-                // Assume that an error means we've reached the end of
-                // a partial WAL record. So that's ok.
-                trace!("WAL decoder error {:?}", rec);
-                break;
-            }
-            if let Some((lsn, recdata)) = rec.unwrap() {
+        while last_lsn <= endpoint {
+            if let Some((lsn, recdata)) = waldecoder.poll_decode()? {
+                let mut checkpoint_modified = false;
+
                 let decoded = decode_wal_record(recdata.clone());
-                save_decoded_record(&mut checkpoint, timeline, &decoded, recdata, lsn)?;
+                save_decoded_record(
+                    checkpoint,
+                    &mut checkpoint_modified,
+                    timeline,
+                    &decoded,
+                    recdata,
+                    lsn,
+                )?;
                 last_lsn = lsn;
-            } else {
-                break;
+
+                if checkpoint_modified {
+                    let checkpoint_bytes = checkpoint.encode();
+                    timeline.put_page_image(
+                        RelishTag::Checkpoint,
+                        0,
+                        last_lsn,
+                        checkpoint_bytes,
+                    )?;
+                }
+
+                // Now that this record has been fully handled, including updating the
+                // checkpoint data, let the repository know that it is up-to-date to this LSN
+                timeline.advance_last_record_lsn(last_lsn);
+                nrecords += 1;
+
+                trace!("imported record at {} (end {})", lsn, endpoint);
             }
-            nrecords += 1;
         }
 
-        info!("imported {} records up to {}", nrecords, last_lsn);
+        debug!("imported {} records up to {}", nrecords, last_lsn);
 
         segno += 1;
         offset = 0;
     }
 
-    info!("reached end of WAL at {}", last_lsn);
-    let checkpoint_bytes = checkpoint.encode();
-    timeline.put_page_image(RelishTag::Checkpoint, 0, last_lsn, checkpoint_bytes, false)?;
+    if last_lsn != startpoint {
+        debug!(
+            "reached end of WAL at {}, updating checkpoint info",
+            last_lsn
+        );
+
+        timeline.advance_last_record_lsn(last_lsn);
+    } else {
+        info!("no WAL to import at {}", last_lsn);
+    }
 
-    timeline.advance_last_valid_lsn(last_lsn);
-    timeline.checkpoint()?;
     Ok(())
 }
 
@@ -347,12 +407,15 @@ pub fn import_timeline_wal(walpath: &Path, timeline: &dyn Timeline, startpoint:
 ///
 pub fn save_decoded_record(
     checkpoint: &mut CheckPoint,
-    timeline: &dyn Timeline,
+    checkpoint_modified: &mut bool,
+    timeline: &dyn TimelineWriter,
     decoded: &DecodedWALRecord,
     recdata: Bytes,
     lsn: Lsn,
 ) -> Result<()> {
-    checkpoint.update_next_xid(decoded.xl_xid);
+    if checkpoint.update_next_xid(decoded.xl_xid) {
+        *checkpoint_modified = true;
+    }
 
     // Iterate through all the blocks that the record modifies, and
     // "put" a separate copy of the record for each block.
@@ -364,14 +427,13 @@ pub fn save_decoded_record(
             forknum: blk.forknum as u8,
         });
 
-        let rec = WALRecord {
-            lsn,
-            will_init: blk.will_init || blk.apply_image,
-            rec: recdata.clone(),
-            main_data_offset: decoded.main_data_offset as u32,
-        };
+        let rec = WALRecord::new(
+            blk.will_init || blk.apply_image,
+            decoded.main_data_offset as u32,
+            &recdata[..],
+        );
 
-        timeline.put_wal_record(tag, blk.blkno, rec)?;
+        timeline.put_wal_record(lsn, tag, blk.blkno, rec)?;
     }
 
     let mut buf = decoded.record.clone();
@@ -387,9 +449,34 @@ pub fn save_decoded_record(
         if (decoded.xl_info & pg_constants::XLR_RMGR_INFO_MASK) == pg_constants::XLOG_DBASE_CREATE {
             let createdb = XlCreateDatabase::decode(&mut buf);
             save_xlog_dbase_create(timeline, lsn, &createdb)?;
-        } else {
-            // TODO
-            trace!("XLOG_DBASE_DROP is not handled yet");
+        } else if (decoded.xl_info & pg_constants::XLR_RMGR_INFO_MASK)
+            == pg_constants::XLOG_DBASE_DROP
+        {
+            let dropdb = XlDropDatabase::decode(&mut buf);
+
+            // To drop the database, we need to drop all the relations in it. Like in
+            // save_xlog_dbase_create(), use the previous record's LSN in the list_rels() call
+            let req_lsn = min(timeline.get_last_record_lsn(), lsn);
+
+            for tablespace_id in dropdb.tablespace_ids {
+                let rels = timeline.list_rels(tablespace_id, dropdb.db_id, req_lsn)?;
+                for rel in rels {
+                    timeline.drop_relish(rel, lsn)?;
+                }
+                trace!(
+                    "Drop FileNodeMap {}, {} at lsn {}",
+                    tablespace_id,
+                    dropdb.db_id,
+                    lsn
+                );
+                timeline.drop_relish(
+                    RelishTag::FileNodeMap {
+                        spcnode: tablespace_id,
+                        dbnode: dropdb.db_id,
+                    },
+                    lsn,
+                )?;
+            }
         }
     } else if decoded.xl_rmid == pg_constants::RM_TBLSPC_ID {
         trace!("XLOG_TBLSPC_CREATE/DROP is not handled yet");
@@ -406,13 +493,12 @@ pub fn save_decoded_record(
                 },
                 rpageno,
                 lsn,
-                ZERO_PAGE,
-                true,
+                ZERO_PAGE.clone(),
             )?;
         } else {
             assert!(info == pg_constants::CLOG_TRUNCATE);
             let xlrec = XlClogTruncate::decode(&mut buf);
-            save_clog_truncate_record(checkpoint, timeline, lsn, &xlrec)?;
+            save_clog_truncate_record(checkpoint, checkpoint_modified, timeline, lsn, &xlrec)?;
         }
     } else if decoded.xl_rmid == pg_constants::RM_XACT_ID {
         let info = decoded.xl_info & pg_constants::XLOG_XACT_OPMASK;
@@ -426,12 +512,12 @@ pub fn save_decoded_record(
             save_xact_record(timeline, lsn, &parsed_xact, decoded)?;
             // Remove twophase file. see RemoveTwoPhaseFile() in postgres code
             trace!(
-                "unlink twophaseFile for xid {} parsed_xact.xid {} here at {}",
+                "Drop twophaseFile for xid {} parsed_xact.xid {} here at {}",
                 decoded.xl_xid,
                 parsed_xact.xid,
                 lsn
             );
-            timeline.put_unlink(
+            timeline.drop_relish(
                 RelishTag::TwoPhase {
                     xid: parsed_xact.xid,
                 },
@@ -448,7 +534,6 @@ pub fn save_decoded_record(
                 0,
                 lsn,
                 Bytes::copy_from_slice(&buf[..]),
-                true,
             )?;
         }
     } else if decoded.xl_rmid == pg_constants::RM_MULTIXACT_ID {
@@ -465,10 +550,9 @@ pub fn save_decoded_record(
                 },
                 rpageno,
                 lsn,
-                ZERO_PAGE,
-                true,
+                ZERO_PAGE.clone(),
             )?;
-        } else if info == pg_constants::XLOG_MULTIXACT_ZERO_OFF_PAGE {
+        } else if info == pg_constants::XLOG_MULTIXACT_ZERO_MEM_PAGE {
             let pageno = buf.get_u32_le();
             let segno = pageno / pg_constants::SLRU_PAGES_PER_SEGMENT;
             let rpageno = pageno % pg_constants::SLRU_PAGES_PER_SEGMENT;
@@ -479,24 +563,33 @@ pub fn save_decoded_record(
                 },
                 rpageno,
                 lsn,
-                ZERO_PAGE,
-                true,
+                ZERO_PAGE.clone(),
             )?;
         } else if info == pg_constants::XLOG_MULTIXACT_CREATE_ID {
             let xlrec = XlMultiXactCreate::decode(&mut buf);
-            save_multixact_create_record(checkpoint, timeline, lsn, &xlrec, decoded)?;
+            save_multixact_create_record(
+                checkpoint,
+                checkpoint_modified,
+                timeline,
+                lsn,
+                &xlrec,
+                decoded,
+            )?;
         } else if info == pg_constants::XLOG_MULTIXACT_TRUNCATE_ID {
             let xlrec = XlMultiXactTruncate::decode(&mut buf);
-            save_multixact_truncate_record(checkpoint, timeline, lsn, &xlrec)?;
+            save_multixact_truncate_record(checkpoint, checkpoint_modified, timeline, lsn, &xlrec)?;
         }
     } else if decoded.xl_rmid == pg_constants::RM_RELMAP_ID {
         let xlrec = XlRelmapUpdate::decode(&mut buf);
-        save_relmap_record(timeline, lsn, &xlrec, decoded)?;
+        save_relmap_page(timeline, lsn, &xlrec, decoded)?;
     } else if decoded.xl_rmid == pg_constants::RM_XLOG_ID {
         let info = decoded.xl_info & pg_constants::XLR_RMGR_INFO_MASK;
         if info == pg_constants::XLOG_NEXTOID {
             let next_oid = buf.get_u32_le();
-            checkpoint.nextOid = next_oid;
+            if checkpoint.nextOid != next_oid {
+                checkpoint.nextOid = next_oid;
+                *checkpoint_modified = true;
+            }
         } else if info == pg_constants::XLOG_CHECKPOINT_ONLINE
             || info == pg_constants::XLOG_CHECKPOINT_SHUTDOWN
         {
@@ -512,17 +605,19 @@ pub fn save_decoded_record(
             );
             if (checkpoint.oldestXid.wrapping_sub(xlog_checkpoint.oldestXid) as i32) < 0 {
                 checkpoint.oldestXid = xlog_checkpoint.oldestXid;
+                *checkpoint_modified = true;
             }
         }
     }
-    // Now that this record has been handled, let the repository know that
-    // it is up-to-date to this LSN
-    timeline.advance_last_record_lsn(lsn);
     Ok(())
 }
 
 /// Subroutine of save_decoded_record(), to handle an XLOG_DBASE_CREATE record.
-fn save_xlog_dbase_create(timeline: &dyn Timeline, lsn: Lsn, rec: &XlCreateDatabase) -> Result<()> {
+fn save_xlog_dbase_create(
+    timeline: &dyn TimelineWriter,
+    lsn: Lsn,
+    rec: &XlCreateDatabase,
+) -> Result<()> {
     let db_id = rec.db_id;
     let tablespace_id = rec.tablespace_id;
     let src_db_id = rec.src_db_id;
@@ -541,56 +636,52 @@ fn save_xlog_dbase_create(timeline: &dyn Timeline, lsn: Lsn, rec: &XlCreateDatab
 
     let mut num_rels_copied = 0;
     let mut num_blocks_copied = 0;
-    for src_rel in rels {
-        assert_eq!(src_rel.spcnode, src_tablespace_id);
-        assert_eq!(src_rel.dbnode, src_db_id);
+    for rel in rels {
+        if let RelishTag::Relation(src_rel) = rel {
+            assert_eq!(src_rel.spcnode, src_tablespace_id);
+            assert_eq!(src_rel.dbnode, src_db_id);
 
-        let nblocks = timeline
-            .get_relish_size(RelishTag::Relation(src_rel), req_lsn)?
-            .unwrap_or(0);
-        let dst_rel = RelTag {
-            spcnode: tablespace_id,
-            dbnode: db_id,
-            relnode: src_rel.relnode,
-            forknum: src_rel.forknum,
-        };
+            let nblocks = timeline.get_relish_size(rel, req_lsn)?.unwrap_or(0);
+            let dst_rel = RelTag {
+                spcnode: tablespace_id,
+                dbnode: db_id,
+                relnode: src_rel.relnode,
+                forknum: src_rel.forknum,
+            };
 
-        // Copy content
-        for blknum in 0..nblocks {
-            let content =
-                timeline.get_page_at_lsn_nowait(RelishTag::Relation(src_rel), blknum, req_lsn)?;
+            // Copy content
+            for blknum in 0..nblocks {
+                let content = timeline.get_page_at_lsn(rel, blknum, req_lsn)?;
 
-            debug!("copying block {} from {} to {}", blknum, src_rel, dst_rel);
+                debug!("copying block {} from {} to {}", blknum, src_rel, dst_rel);
 
-            timeline.put_page_image(RelishTag::Relation(dst_rel), blknum, lsn, content, true)?;
-            num_blocks_copied += 1;
+                timeline.put_page_image(RelishTag::Relation(dst_rel), blknum, lsn, content)?;
+                num_blocks_copied += 1;
+            }
+
+            if nblocks == 0 {
+                // make sure we have some trace of the relation, even if it's empty
+                timeline.put_truncation(RelishTag::Relation(dst_rel), lsn, 0)?;
+            }
+
+            num_rels_copied += 1;
         }
-
-        if nblocks == 0 {
-            // make sure we have some trace of the relation, even if it's empty
-            timeline.put_truncation(RelishTag::Relation(dst_rel), lsn, 0)?;
-        }
-
-        num_rels_copied += 1;
     }
 
     // Copy relfilemap
     // TODO This implementation is very inefficient -
     // it scans all non-rels only to find FileNodeMaps
     for tag in timeline.list_nonrels(req_lsn)? {
-        match tag {
-            RelishTag::FileNodeMap { spcnode, dbnode } => {
-                if spcnode == src_tablespace_id && dbnode == src_db_id {
-                    let img = timeline.get_page_at_lsn_nowait(tag, 0, req_lsn)?;
-                    let new_tag = RelishTag::FileNodeMap {
-                        spcnode: tablespace_id,
-                        dbnode: db_id,
-                    };
-                    timeline.put_page_image(new_tag, 0, lsn, img, false)?;
-                    break;
-                }
+        if let RelishTag::FileNodeMap { spcnode, dbnode } = tag {
+            if spcnode == src_tablespace_id && dbnode == src_db_id {
+                let img = timeline.get_page_at_lsn(tag, 0, req_lsn)?;
+                let new_tag = RelishTag::FileNodeMap {
+                    spcnode: tablespace_id,
+                    dbnode: db_id,
+                };
+                timeline.put_page_image(new_tag, 0, lsn, img)?;
+                break;
             }
-            _ => {} // do nothing
         }
     }
     info!(
@@ -603,7 +694,11 @@ fn save_xlog_dbase_create(timeline: &dyn Timeline, lsn: Lsn, rec: &XlCreateDatab
 /// Subroutine of save_decoded_record(), to handle an XLOG_SMGR_TRUNCATE record.
 ///
 /// This is the same logic as in PostgreSQL's smgr_redo() function.
-fn save_xlog_smgr_truncate(timeline: &dyn Timeline, lsn: Lsn, rec: &XlSmgrTruncate) -> Result<()> {
+fn save_xlog_smgr_truncate(
+    timeline: &dyn TimelineWriter,
+    lsn: Lsn,
+    rec: &XlSmgrTruncate,
+) -> Result<()> {
     let spcnode = rec.rnode.spcnode;
     let dbnode = rec.rnode.dbnode;
     let relnode = rec.rnode.relnode;
@@ -664,9 +759,8 @@ fn save_xlog_smgr_truncate(timeline: &dyn Timeline, lsn: Lsn, rec: &XlSmgrTrunca
 
 /// Subroutine of save_decoded_record(), to handle an XLOG_XACT_* records.
 ///
-/// We are currently only interested in the dropped relations.
 fn save_xact_record(
-    timeline: &dyn Timeline,
+    timeline: &dyn TimelineWriter,
     lsn: Lsn,
     parsed: &XlXactParsedRecord,
     decoded: &DecodedWALRecord,
@@ -676,13 +770,9 @@ fn save_xact_record(
 
     let segno = pageno / pg_constants::SLRU_PAGES_PER_SEGMENT;
     let rpageno = pageno % pg_constants::SLRU_PAGES_PER_SEGMENT;
-    let rec = WALRecord {
-        lsn,
-        will_init: false,
-        rec: decoded.record.clone(),
-        main_data_offset: decoded.main_data_offset as u32,
-    };
+    let rec = WALRecord::new(false, decoded.main_data_offset as u32, &decoded.record[..]);
     timeline.put_wal_record(
+        lsn,
         RelishTag::Slru {
             slru: SlruKind::Clog,
             segno,
@@ -698,6 +788,7 @@ fn save_xact_record(
             let segno = pageno / pg_constants::SLRU_PAGES_PER_SEGMENT;
             let rpageno = pageno % pg_constants::SLRU_PAGES_PER_SEGMENT;
             timeline.put_wal_record(
+                lsn,
                 RelishTag::Slru {
                     slru: SlruKind::Clog,
                     segno,
@@ -715,53 +806,16 @@ fn save_xact_record(
                 dbnode: xnode.dbnode,
                 relnode: xnode.relnode,
             };
-            timeline.put_unlink(RelishTag::Relation(rel), lsn)?;
+            timeline.drop_relish(RelishTag::Relation(rel), lsn)?;
         }
     }
     Ok(())
 }
 
-// See TransactionIdPrecedes in transam.c
-fn transaction_id_precedes(id1: TransactionId, id2: TransactionId) -> bool {
-    /*
-     * If either ID is a permanent XID then we can just do unsigned
-     * comparison.  If both are normal, do a modulo-2^32 comparison.
-     */
-
-    if !(id1 >= pg_constants::FIRST_NORMAL_TRANSACTION_ID)
-        || !(id2 >= pg_constants::FIRST_NORMAL_TRANSACTION_ID)
-    {
-        return id1 < id2;
-    }
-
-    let diff = id1.wrapping_sub(id2) as i32;
-    return diff < 0;
-}
-
-// See CLOGPagePrecedes in clog.c
-fn clogpage_precedes(page1: u32, page2: u32) -> bool {
-    let mut xid1 = page1 * pg_constants::CLOG_XACTS_PER_PAGE;
-    xid1 += pg_constants::FIRST_NORMAL_TRANSACTION_ID + 1;
-    let mut xid2 = page2 * pg_constants::CLOG_XACTS_PER_PAGE;
-    xid2 += pg_constants::FIRST_NORMAL_TRANSACTION_ID + 1;
-
-    return transaction_id_precedes(xid1, xid2)
-        && transaction_id_precedes(xid1, xid2 + pg_constants::CLOG_XACTS_PER_PAGE - 1);
-}
-
-// See SlruMayDeleteSegment() in slru.c
-fn slru_may_delete_clogsegment(segpage: u32, cutoff_page: u32) -> bool {
-    let seg_last_page = segpage + pg_constants::SLRU_PAGES_PER_SEGMENT - 1;
-
-    assert_eq!(segpage % pg_constants::SLRU_PAGES_PER_SEGMENT, 0);
-
-    return clogpage_precedes(segpage, cutoff_page)
-        && clogpage_precedes(seg_last_page, cutoff_page);
-}
-
 fn save_clog_truncate_record(
     checkpoint: &mut CheckPoint,
-    timeline: &dyn Timeline,
+    checkpoint_modified: &mut bool,
+    timeline: &dyn TimelineWriter,
     lsn: Lsn,
     xlrec: &XlClogTruncate,
 ) -> Result<()> {
@@ -779,6 +833,7 @@ fn save_clog_truncate_record(
     // TODO Figure out if there will be any issues with replica.
     checkpoint.oldestXid = xlrec.oldest_xid;
     checkpoint.oldestXidDB = xlrec.oldest_xid_db;
+    *checkpoint_modified = true;
 
     // TODO Treat AdvanceOldestClogXid() or write a comment why we don't need it
 
@@ -795,7 +850,7 @@ fn save_clog_truncate_record(
         return Ok(());
     }
 
-    // Iterate via SLRU CLOG segments and unlink segments that we're ready to truncate
+    // Iterate via SLRU CLOG segments and drop segments that we're ready to truncate
     // TODO This implementation is very inefficient -
     // it scans all non-rels only to find Clog
     //
@@ -805,17 +860,14 @@ fn save_clog_truncate_record(
     // instead.
     let req_lsn = min(timeline.get_last_record_lsn(), lsn);
     for obj in timeline.list_nonrels(req_lsn)? {
-        match obj {
-            RelishTag::Slru { slru, segno } => {
-                if slru == SlruKind::Clog {
-                    let segpage = segno * pg_constants::SLRU_PAGES_PER_SEGMENT;
-                    if slru_may_delete_clogsegment(segpage, xlrec.pageno) {
-                        timeline.put_unlink(RelishTag::Slru { slru, segno }, lsn)?;
-                        trace!("unlink CLOG segment {:>04X} at lsn {}", segno, lsn);
-                    }
+        if let RelishTag::Slru { slru, segno } = obj {
+            if slru == SlruKind::Clog {
+                let segpage = segno * pg_constants::SLRU_PAGES_PER_SEGMENT;
+                if slru_may_delete_clogsegment(segpage, xlrec.pageno) {
+                    timeline.drop_relish(RelishTag::Slru { slru, segno }, lsn)?;
+                    trace!("Drop CLOG segment {:>04X} at lsn {}", segno, lsn);
                 }
             }
-            _ => {}
         }
     }
 
@@ -824,21 +876,18 @@ fn save_clog_truncate_record(
 
 fn save_multixact_create_record(
     checkpoint: &mut CheckPoint,
-    timeline: &dyn Timeline,
+    checkpoint_modified: &mut bool,
+    timeline: &dyn TimelineWriter,
     lsn: Lsn,
     xlrec: &XlMultiXactCreate,
     decoded: &DecodedWALRecord,
 ) -> Result<()> {
-    let rec = WALRecord {
-        lsn,
-        will_init: false,
-        rec: decoded.record.clone(),
-        main_data_offset: decoded.main_data_offset as u32,
-    };
+    let rec = WALRecord::new(false, decoded.main_data_offset as u32, &decoded.record[..]);
     let pageno = xlrec.mid / pg_constants::MULTIXACT_OFFSETS_PER_PAGE as u32;
     let segno = pageno / pg_constants::SLRU_PAGES_PER_SEGMENT;
     let rpageno = pageno % pg_constants::SLRU_PAGES_PER_SEGMENT;
     timeline.put_wal_record(
+        lsn,
         RelishTag::Slru {
             slru: SlruKind::MultiXactOffsets,
             segno,
@@ -858,6 +907,7 @@ fn save_multixact_create_record(
         let segno = pageno / pg_constants::SLRU_PAGES_PER_SEGMENT;
         let rpageno = pageno % pg_constants::SLRU_PAGES_PER_SEGMENT;
         timeline.put_wal_record(
+            lsn,
             RelishTag::Slru {
                 slru: SlruKind::MultiXactMembers,
                 segno,
@@ -880,9 +930,11 @@ fn save_multixact_create_record(
     }
     if xlrec.mid >= checkpoint.nextMulti {
         checkpoint.nextMulti = xlrec.mid + 1;
+        *checkpoint_modified = true;
     }
     if xlrec.moff + xlrec.nmembers > checkpoint.nextMultiOffset {
         checkpoint.nextMultiOffset = xlrec.moff + xlrec.nmembers;
+        *checkpoint_modified = true;
     }
     let max_mbr_xid = xlrec.members.iter().fold(0u32, |acc, mbr| {
         if mbr.xid.wrapping_sub(acc) as i32 > 0 {
@@ -892,41 +944,33 @@ fn save_multixact_create_record(
         }
     });
 
-    checkpoint.update_next_xid(max_mbr_xid);
+    if checkpoint.update_next_xid(max_mbr_xid) {
+        *checkpoint_modified = true;
+    }
     Ok(())
 }
 
-#[allow(non_upper_case_globals)]
-const MaxMultiXactOffset: u32 = 0xFFFFFFFF;
-
-#[allow(non_snake_case)]
-const fn MXOffsetToMemberPage(xid: u32) -> u32 {
-    xid / pg_constants::MULTIXACT_MEMBERS_PER_PAGE as u32
-}
-#[allow(non_snake_case)]
-const fn MXOffsetToMemberSegment(xid: u32) -> i32 {
-    (MXOffsetToMemberPage(xid) / pg_constants::SLRU_PAGES_PER_SEGMENT) as i32
-}
-
 fn save_multixact_truncate_record(
     checkpoint: &mut CheckPoint,
-    timeline: &dyn Timeline,
+    checkpoint_modified: &mut bool,
+    timeline: &dyn TimelineWriter,
     lsn: Lsn,
     xlrec: &XlMultiXactTruncate,
 ) -> Result<()> {
     checkpoint.oldestMulti = xlrec.end_trunc_off;
     checkpoint.oldestMultiDB = xlrec.oldest_multi_db;
+    *checkpoint_modified = true;
 
     // PerformMembersTruncation
-    let maxsegment: i32 = MXOffsetToMemberSegment(MaxMultiXactOffset);
-    let startsegment: i32 = MXOffsetToMemberSegment(xlrec.start_trunc_memb);
-    let endsegment: i32 = MXOffsetToMemberSegment(xlrec.end_trunc_memb);
+    let maxsegment: i32 = mx_offset_to_member_segment(pg_constants::MAX_MULTIXACT_OFFSET);
+    let startsegment: i32 = mx_offset_to_member_segment(xlrec.start_trunc_memb);
+    let endsegment: i32 = mx_offset_to_member_segment(xlrec.end_trunc_memb);
     let mut segment: i32 = startsegment;
 
     // Delete all the segments except the last one. The last segment can still
     // contain, possibly partially, valid data.
     while segment != endsegment {
-        timeline.put_unlink(
+        timeline.drop_relish(
             RelishTag::Slru {
                 slru: SlruKind::MultiXactMembers,
                 segno: segment as u32,
@@ -948,22 +992,23 @@ fn save_multixact_truncate_record(
     Ok(())
 }
 
-fn save_relmap_record(
-    timeline: &dyn Timeline,
+fn save_relmap_page(
+    timeline: &dyn TimelineWriter,
     lsn: Lsn,
     xlrec: &XlRelmapUpdate,
     decoded: &DecodedWALRecord,
 ) -> Result<()> {
-    let rec = WALRecord {
-        lsn,
-        will_init: true,
-        rec: decoded.record.clone(),
-        main_data_offset: decoded.main_data_offset as u32,
-    };
     let tag = RelishTag::FileNodeMap {
         spcnode: xlrec.tsid,
         dbnode: xlrec.dbid,
     };
-    timeline.put_wal_record(tag, 0, rec)?;
+
+    let mut buf = decoded.record.clone();
+    buf.advance(decoded.main_data_offset);
+    // skip xl_relmap_update
+    buf.advance(12);
+
+    timeline.put_page_image(tag, 0, lsn, Bytes::copy_from_slice(&buf[..]))?;
+
     Ok(())
 }

pageserver/src/rocksdb_storage.rs

@@ -1,475 +0,0 @@
-//!
-//! An implementation of the ObjectStore interface, backed by RocksDB
-//!
-use crate::object_key::*;
-use crate::object_store::ObjectStore;
-use crate::relish::*;
-use crate::PageServerConf;
-use anyhow::{bail, Result};
-use serde::{Deserialize, Serialize};
-use std::collections::HashSet;
-use std::sync::{Arc, Mutex};
-use zenith_utils::bin_ser::BeSer;
-use zenith_utils::lsn::Lsn;
-use zenith_utils::zid::ZTenantId;
-use zenith_utils::zid::ZTimelineId;
-
-#[derive(Debug, Clone, Serialize, Deserialize)]
-struct StorageKey {
-    obj_key: ObjectKey,
-    lsn: Lsn,
-}
-
-impl StorageKey {
-    /// The first key for a given timeline
-    fn timeline_start(timeline: ZTimelineId) -> Self {
-        Self {
-            obj_key: ObjectKey {
-                timeline,
-                tag: ObjectTag::TimelineMetadataTag,
-            },
-            lsn: Lsn(0),
-        }
-    }
-}
-
-///
-/// RocksDB very inefficiently delete random record. Instead of it we have to use merge
-/// filter, which allows to throw away records at LSM merge phase.
-/// Unfortunately, it is hard (if ever possible)  to determine whether version can be removed
-/// at merge time. Version ca be removed if:
-/// 1. It is above PITR horizon (we need to get current LSN and gc_horizon from config)
-/// 2. Page is reconstructed at horizon (all WAL records above horizon are applied and can be removed)
-///
-/// So we have GC process which reconstructs pages at horizon and mark deteriorated WAL record
-/// for deletion. To mark object for deletion we can either set some flag in object itself.
-/// But it is complicated with new object value format, because RocksDB storage knows nothing about
-/// this format. Also updating whole record just to set one bit seems to be inefficient in any case.
-/// This is why we keep keys of marked for deletion versions in HashSet in memory.
-/// When LSM merge filter found key in this map, it removes it from the set preventing memory overflow.
-///
-struct GarbageCollector {
-    garbage: Mutex<HashSet<Vec<u8>>>,
-}
-
-impl GarbageCollector {
-    fn new() -> GarbageCollector {
-        GarbageCollector {
-            garbage: Mutex::new(HashSet::new()),
-        }
-    }
-
-    /// Called by GC to mark version as delete
-    fn mark_for_deletion(&self, key: &[u8]) {
-        let mut garbage = self.garbage.lock().unwrap();
-        garbage.insert(key.to_vec());
-    }
-
-    /// Called by LSM merge filter. If it finds key in the set, then
-    /// it doesn't merge it and removes from this set.
-    fn was_deleted(&self, key: &[u8]) -> bool {
-        let key = key.to_vec();
-        let mut garbage = self.garbage.lock().unwrap();
-        garbage.remove(&key)
-    }
-}
-
-pub struct RocksObjectStore {
-    _conf: &'static PageServerConf,
-
-    // RocksDB handle
-    db: rocksdb::DB,
-    gc: Arc<GarbageCollector>,
-}
-
-impl ObjectStore for RocksObjectStore {
-    fn get(&self, key: &ObjectKey, lsn: Lsn) -> Result<Vec<u8>> {
-        let val = self.db.get(StorageKey::ser(&StorageKey {
-            obj_key: key.clone(),
-            lsn,
-        })?)?;
-        if let Some(val) = val {
-            Ok(val)
-        } else {
-            bail!("could not find page {:?}", key);
-        }
-    }
-
-    fn get_next_key(&self, key: &ObjectKey) -> Result<Option<ObjectKey>> {
-        let mut iter = self.db.raw_iterator();
-        let search_key = StorageKey {
-            obj_key: key.clone(),
-            lsn: Lsn(0),
-        };
-        iter.seek(search_key.ser()?);
-        if !iter.valid() {
-            Ok(None)
-        } else {
-            let key = StorageKey::des(iter.key().unwrap())?;
-            Ok(Some(key.obj_key.clone()))
-        }
-    }
-
-    fn put(&self, key: &ObjectKey, lsn: Lsn, value: &[u8]) -> Result<()> {
-        self.db.put(
-            StorageKey::ser(&StorageKey {
-                obj_key: key.clone(),
-                lsn,
-            })?,
-            value,
-        )?;
-        Ok(())
-    }
-
-    fn unlink(&self, key: &ObjectKey, lsn: Lsn) -> Result<()> {
-        self.gc.mark_for_deletion(&StorageKey::ser(&StorageKey {
-            obj_key: key.clone(),
-            lsn,
-        })?);
-        Ok(())
-    }
-
-    /// Iterate through page versions of given page, starting from the given LSN.
-    /// The versions are walked in descending LSN order.
-    fn object_versions<'a>(
-        &'a self,
-        key: &ObjectKey,
-        lsn: Lsn,
-    ) -> Result<Box<dyn Iterator<Item = (Lsn, Vec<u8>)> + 'a>> {
-        let iter = RocksObjectVersionIter::new(&self.db, key, lsn)?;
-        Ok(Box::new(iter))
-    }
-
-    /// Iterate through all timeline objects
-    fn list_objects<'a>(
-        &'a self,
-        timeline: ZTimelineId,
-        lsn: Lsn,
-    ) -> Result<Box<dyn Iterator<Item = ObjectTag> + 'a>> {
-        let iter = RocksObjectIter::new(&self.db, timeline, lsn)?;
-        Ok(Box::new(iter))
-    }
-
-    /// Get a list of all distinct relations in given tablespace and database.
-    ///
-    /// TODO: This implementation is very inefficient, it scans
-    /// through all entries in the given database. In practice, this
-    /// is used for CREATE DATABASE, and usually the template database is small.
-    /// But if it's not, this will be slow.
-    fn list_rels(
-        &self,
-        timelineid: ZTimelineId,
-        spcnode: u32,
-        dbnode: u32,
-        lsn: Lsn,
-    ) -> Result<HashSet<RelTag>> {
-        // FIXME: This scans everything. Very slow
-
-        let mut rels: HashSet<RelTag> = HashSet::new();
-
-        let mut search_rel_tag = RelTag {
-            spcnode,
-            dbnode,
-            relnode: 0,
-            forknum: 0u8,
-        };
-        let mut iter = self.db.raw_iterator();
-        loop {
-            let search_key = StorageKey {
-                obj_key: ObjectKey {
-                    timeline: timelineid,
-                    tag: ObjectTag::RelationMetadata(RelishTag::Relation(search_rel_tag)),
-                },
-                lsn: Lsn(0),
-            };
-            iter.seek(search_key.ser()?);
-            if !iter.valid() {
-                break;
-            }
-            let key = StorageKey::des(iter.key().unwrap())?;
-
-            if let ObjectTag::RelationMetadata(RelishTag::Relation(rel_tag)) = key.obj_key.tag {
-                if spcnode != 0 && rel_tag.spcnode != spcnode
-                    || dbnode != 0 && rel_tag.dbnode != dbnode
-                {
-                    break;
-                }
-                if key.lsn <= lsn {
-                    // visible in this snapshot
-                    rels.insert(rel_tag);
-                }
-                search_rel_tag = rel_tag;
-                // skip to next relation
-                // FIXME: What if relnode is u32::MAX ?
-                search_rel_tag.relnode += 1;
-            } else {
-                // no more relation metadata entries
-                break;
-            }
-        }
-
-        Ok(rels)
-    }
-
-    /// Get a list of all distinct NON-relations in timeline
-    /// that are visible at given lsn.
-    ///
-    /// TODO: This implementation is very inefficient, it scans
-    /// through all non-rel page versions in the system. In practice, this
-    /// is used when initializing a new compute node, and the non-rel files
-    /// are never very large nor change very frequently, so this will do for now.
-    fn list_nonrels(&self, timelineid: ZTimelineId, lsn: Lsn) -> Result<HashSet<RelishTag>> {
-        let mut rels: HashSet<RelishTag> = HashSet::new();
-
-        let search_key = StorageKey {
-            obj_key: ObjectKey {
-                timeline: timelineid,
-                tag: ObjectTag::Buffer(FIRST_NONREL_RELISH_TAG, 0),
-            },
-            lsn: Lsn(0),
-        };
-
-        let mut iter = self.db.raw_iterator();
-        iter.seek(search_key.ser()?);
-        while iter.valid() {
-            let key = StorageKey::des(iter.key().unwrap())?;
-
-            if key.obj_key.timeline != timelineid {
-                // reached end of this timeline in the store
-                break;
-            }
-
-            if let ObjectTag::Buffer(rel_tag, _blknum) = key.obj_key.tag {
-                if key.lsn <= lsn {
-                    // visible in this snapshot
-                    rels.insert(rel_tag);
-                }
-            }
-            // TODO: we could skip to next relation here like we do in list_rels(),
-            // but hopefully there are not that many SLRU segments or other non-rel
-            // entries for it to matter.
-            iter.next();
-        }
-
-        Ok(rels)
-    }
-
-    /// Iterate through versions of all objects in a timeline.
-    ///
-    /// Returns objects in increasing key-version order.
-    /// Returns all versions up to and including the specified LSN.
-    fn objects<'a>(
-        &'a self,
-        timeline: ZTimelineId,
-        lsn: Lsn,
-    ) -> Result<Box<dyn Iterator<Item = Result<(ObjectTag, Lsn, Vec<u8>)>> + 'a>> {
-        let start_key = StorageKey::timeline_start(timeline);
-        let start_key_bytes = StorageKey::ser(&start_key)?;
-        let iter = self.db.iterator(rocksdb::IteratorMode::From(
-            &start_key_bytes,
-            rocksdb::Direction::Forward,
-        ));
-
-        Ok(Box::new(RocksObjects {
-            iter,
-            timeline,
-            lsn,
-        }))
-    }
-
-    fn compact(&self) {
-        self.db.compact_range::<&[u8], &[u8]>(None, None);
-    }
-}
-
-impl RocksObjectStore {
-    /// Open a RocksDB database.
-    pub fn open(conf: &'static PageServerConf, tenantid: &ZTenantId) -> Result<RocksObjectStore> {
-        let opts = Self::get_rocksdb_opts();
-        let obj_store = Self::new(conf, opts, tenantid)?;
-        Ok(obj_store)
-    }
-
-    /// Create a new, empty RocksDB database.
-    pub fn create(conf: &'static PageServerConf, tenantid: &ZTenantId) -> Result<RocksObjectStore> {
-        let path = conf.tenant_path(&tenantid).join("rocksdb-storage");
-        std::fs::create_dir(&path)?;
-
-        let mut opts = Self::get_rocksdb_opts();
-        opts.create_if_missing(true);
-        opts.set_error_if_exists(true);
-        let obj_store = Self::new(conf, opts, tenantid)?;
-        Ok(obj_store)
-    }
-
-    fn new(
-        conf: &'static PageServerConf,
-        mut opts: rocksdb::Options,
-        tenantid: &ZTenantId,
-    ) -> Result<RocksObjectStore> {
-        let path = conf.tenant_path(&tenantid).join("rocksdb-storage");
-        let gc = Arc::new(GarbageCollector::new());
-        let gc_ref = gc.clone();
-        opts.set_compaction_filter("ttl", move |_level: u32, key: &[u8], _val: &[u8]| {
-            if gc_ref.was_deleted(key) {
-                rocksdb::compaction_filter::Decision::Remove
-            } else {
-                rocksdb::compaction_filter::Decision::Keep
-            }
-        });
-        let db = rocksdb::DB::open(&opts, &path)?;
-        let obj_store = RocksObjectStore {
-            _conf: conf,
-            db,
-            gc,
-        };
-        Ok(obj_store)
-    }
-
-    /// common options used by `open` and `create`
-    fn get_rocksdb_opts() -> rocksdb::Options {
-        let mut opts = rocksdb::Options::default();
-        opts.set_use_fsync(true);
-        opts.set_compression_type(rocksdb::DBCompressionType::Lz4);
-        opts
-    }
-}
-
-///
-/// Iterator for `object_versions`. Returns all page versions of a given block, in
-/// reverse LSN order.
-///
-struct RocksObjectVersionIter<'a> {
-    obj_key: ObjectKey,
-    dbiter: rocksdb::DBRawIterator<'a>,
-    first_call: bool,
-}
-impl<'a> RocksObjectVersionIter<'a> {
-    fn new(
-        db: &'a rocksdb::DB,
-        obj_key: &ObjectKey,
-        lsn: Lsn,
-    ) -> Result<RocksObjectVersionIter<'a>> {
-        let key = StorageKey {
-            obj_key: obj_key.clone(),
-            lsn,
-        };
-        let mut dbiter = db.raw_iterator();
-        dbiter.seek_for_prev(StorageKey::ser(&key)?); // locate last entry
-        Ok(RocksObjectVersionIter {
-            first_call: true,
-            obj_key: obj_key.clone(),
-            dbiter,
-        })
-    }
-}
-impl<'a> Iterator for RocksObjectVersionIter<'a> {
-    type Item = (Lsn, Vec<u8>);
-
-    fn next(&mut self) -> std::option::Option<Self::Item> {
-        if self.first_call {
-            self.first_call = false;
-        } else {
-            self.dbiter.prev(); // walk backwards
-        }
-
-        if !self.dbiter.valid() {
-            return None;
-        }
-        let key = StorageKey::des(self.dbiter.key().unwrap()).unwrap();
-        if key.obj_key.tag != self.obj_key.tag {
-            return None;
-        }
-        let val = self.dbiter.value().unwrap();
-        let result = val.to_vec();
-
-        Some((key.lsn, result))
-    }
-}
-
-struct RocksObjects<'r> {
-    iter: rocksdb::DBIterator<'r>,
-    timeline: ZTimelineId,
-    lsn: Lsn,
-}
-
-impl<'r> Iterator for RocksObjects<'r> {
-    // TODO consider returning Box<[u8]>
-    type Item = Result<(ObjectTag, Lsn, Vec<u8>)>;
-
-    fn next(&mut self) -> Option<Self::Item> {
-        self.next_result().transpose()
-    }
-}
-
-impl<'r> RocksObjects<'r> {
-    fn next_result(&mut self) -> Result<Option<(ObjectTag, Lsn, Vec<u8>)>> {
-        for (key_bytes, v) in &mut self.iter {
-            let key = StorageKey::des(&key_bytes)?;
-
-            if key.obj_key.timeline != self.timeline {
-                return Ok(None);
-            }
-
-            if key.lsn > self.lsn {
-                // TODO can speed up by seeking iterator
-                continue;
-            }
-
-            return Ok(Some((key.obj_key.tag, key.lsn, v.to_vec())));
-        }
-
-        Ok(None)
-    }
-}
-
-///
-/// Iterator for `list_objects`. Returns all objects preceeding specified LSN
-///
-struct RocksObjectIter<'a> {
-    timeline: ZTimelineId,
-    key: StorageKey,
-    lsn: Lsn,
-    dbiter: rocksdb::DBRawIterator<'a>,
-}
-impl<'a> RocksObjectIter<'a> {
-    fn new(db: &'a rocksdb::DB, timeline: ZTimelineId, lsn: Lsn) -> Result<RocksObjectIter<'a>> {
-        let key = StorageKey {
-            obj_key: ObjectKey {
-                timeline,
-                tag: ObjectTag::FirstTag,
-            },
-            lsn: Lsn(0),
-        };
-        let dbiter = db.raw_iterator();
-        Ok(RocksObjectIter {
-            key,
-            timeline,
-            lsn,
-            dbiter,
-        })
-    }
-}
-impl<'a> Iterator for RocksObjectIter<'a> {
-    type Item = ObjectTag;
-
-    fn next(&mut self) -> std::option::Option<Self::Item> {
-        loop {
-            self.dbiter.seek(StorageKey::ser(&self.key).unwrap());
-            if !self.dbiter.valid() {
-                return None;
-            }
-            let key = StorageKey::des(self.dbiter.key().unwrap()).unwrap();
-            if key.obj_key.timeline != self.timeline {
-                // End of this timeline
-                return None;
-            }
-            self.key = key.clone();
-            self.key.lsn = Lsn(u64::MAX); // next seek should skip all versions
-            if key.lsn <= self.lsn {
-                // visible in this snapshot
-                return Some(key.obj_key.tag);
-            }
-        }
-    }
-}

pageserver/src/tenant_mgr.rs

@@ -0,0 +1,278 @@
+//! This module acts as a switchboard to access different repositories managed by this
+//! page server.
+
+use crate::branches;
+use crate::layered_repository::LayeredRepository;
+use crate::repository::{Repository, Timeline};
+use crate::tenant_threads;
+use crate::walredo::PostgresRedoManager;
+use crate::PageServerConf;
+use anyhow::{anyhow, bail, Context, Result};
+use lazy_static::lazy_static;
+use log::{debug, info};
+use serde::{Deserialize, Serialize};
+use std::collections::HashMap;
+use std::fmt;
+use std::fs;
+use std::str::FromStr;
+use std::sync::atomic::{AtomicBool, Ordering};
+use std::sync::{Arc, Mutex, MutexGuard};
+use zenith_utils::zid::{ZTenantId, ZTimelineId};
+
+lazy_static! {
+    static ref TENANTS: Mutex<HashMap<ZTenantId, Tenant>> = Mutex::new(HashMap::new());
+}
+
+struct Tenant {
+    state: TenantState,
+    repo: Option<Arc<dyn Repository>>,
+}
+
+#[derive(Debug, Serialize, Deserialize, Clone, Copy, PartialEq, Eq)]
+pub enum TenantState {
+    // This tenant only exists in cloud storage. It cannot be accessed.
+    CloudOnly,
+    // This tenant exists in cloud storage, and we are currently downloading it to local disk.
+    // It cannot be accessed yet, not until it's been fully downloaded to local disk.
+    Downloading,
+    // All data for this tenant is complete on local disk, but we haven't loaded the Repository,
+    // Timeline and Layer structs into memory yet, so it cannot be accessed yet.
+    //Ready,
+    // This tenant exists on local disk, and the layer map has been loaded into memory.
+    // The local disk might have some newer files that don't exist in cloud storage yet.
+    Active,
+    // Tenant is active, but there is no walreceiver connection.
+    Idle,
+    // This tenant exists on local disk, and the layer map has been loaded into memory.
+    // The local disk might have some newer files that don't exist in cloud storage yet.
+    // The tenant cannot be accessed anymore for any reason, but graceful shutdown.
+    Stopping,
+}
+
+impl fmt::Display for TenantState {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            TenantState::CloudOnly => f.write_str("CloudOnly"),
+            TenantState::Downloading => f.write_str("Downloading"),
+            TenantState::Active => f.write_str("Active"),
+            TenantState::Idle => f.write_str("Idle"),
+            TenantState::Stopping => f.write_str("Stopping"),
+        }
+    }
+}
+
+fn access_tenants() -> MutexGuard<'static, HashMap<ZTenantId, Tenant>> {
+    TENANTS.lock().unwrap()
+}
+
+static SHUTDOWN_REQUESTED: AtomicBool = AtomicBool::new(false);
+
+pub fn init(conf: &'static PageServerConf) {
+    for dir_entry in fs::read_dir(conf.tenants_path()).unwrap() {
+        let tenantid =
+            ZTenantId::from_str(dir_entry.unwrap().file_name().to_str().unwrap()).unwrap();
+
+        {
+            let mut m = access_tenants();
+            let tenant = Tenant {
+                state: TenantState::CloudOnly,
+                repo: None,
+            };
+            m.insert(tenantid, tenant);
+        }
+
+        init_repo(conf, tenantid);
+        info!("initialized storage for tenant: {}", &tenantid);
+    }
+}
+
+fn init_repo(conf: &'static PageServerConf, tenant_id: ZTenantId) {
+    // Set up a WAL redo manager, for applying WAL records.
+    let walredo_mgr = PostgresRedoManager::new(conf, tenant_id);
+
+    // Set up an object repository, for actual data storage.
+    let repo = Arc::new(LayeredRepository::new(
+        conf,
+        Arc::new(walredo_mgr),
+        tenant_id,
+        true,
+    ));
+
+    let mut m = access_tenants();
+    let tenant = m.get_mut(&tenant_id).unwrap();
+    tenant.repo = Some(repo);
+    tenant.state = TenantState::Idle;
+}
+
+pub fn register_timeline_download(
+    conf: &'static PageServerConf,
+    tenant_id: ZTenantId,
+    timeline_id: ZTimelineId,
+) {
+    log::info!(
+        "Registering new download, tenant id {}, timeline id: {}",
+        tenant_id,
+        timeline_id
+    );
+
+    {
+        let mut m = access_tenants();
+        let tenant = m.entry(tenant_id).or_insert_with(|| Tenant {
+            state: TenantState::Downloading,
+            repo: None,
+        });
+        tenant.state = TenantState::Downloading;
+        match &tenant.repo {
+            Some(repo) => {
+                init_timeline(repo.as_ref(), timeline_id);
+                tenant.state = TenantState::Idle;
+                return;
+            }
+            None => log::warn!("Initialize new repo"),
+        }
+        tenant.state = TenantState::Idle;
+    }
+
+    // init repo updates Tenant state
+    init_repo(conf, tenant_id);
+    let new_repo = get_repository_for_tenant(tenant_id).unwrap();
+    init_timeline(new_repo.as_ref(), timeline_id);
+}
+
+fn init_timeline(repo: &dyn Repository, timeline_id: ZTimelineId) {
+    match repo.get_timeline(timeline_id) {
+        Ok(_timeline) => log::info!("Successfully initialized timeline {}", timeline_id),
+        Err(e) => log::error!("Failed to init timeline {}, reason: {:#}", timeline_id, e),
+    }
+}
+
+// Check this flag in the thread loops to know when to exit
+pub fn shutdown_requested() -> bool {
+    SHUTDOWN_REQUESTED.load(Ordering::Relaxed)
+}
+
+pub fn shutdown_all_tenants() -> Result<()> {
+    SHUTDOWN_REQUESTED.swap(true, Ordering::Relaxed);
+
+    let tenantids = list_tenantids()?;
+
+    for tenantid in &tenantids {
+        set_tenant_state(*tenantid, TenantState::Stopping)?;
+    }
+
+    for tenantid in tenantids {
+        // Wait for checkpointer and GC to finish their job
+        tenant_threads::wait_for_tenant_threads_to_stop(tenantid);
+
+        let repo = get_repository_for_tenant(tenantid)?;
+        debug!("shutdown tenant {}", tenantid);
+        repo.shutdown()?;
+    }
+    Ok(())
+}
+
+pub fn create_repository_for_tenant(
+    conf: &'static PageServerConf,
+    tenantid: ZTenantId,
+) -> Result<()> {
+    {
+        let mut m = access_tenants();
+        // First check that the tenant doesn't exist already
+        if m.get(&tenantid).is_some() {
+            bail!("tenant {} already exists", tenantid);
+        }
+        let tenant = Tenant {
+            state: TenantState::CloudOnly,
+            repo: None,
+        };
+        m.insert(tenantid, tenant);
+    }
+
+    let wal_redo_manager = Arc::new(PostgresRedoManager::new(conf, tenantid));
+    let repo = branches::create_repo(conf, tenantid, wal_redo_manager)?;
+
+    let mut m = access_tenants();
+    let tenant = m.get_mut(&tenantid).unwrap();
+    tenant.repo = Some(repo);
+    tenant.state = TenantState::Idle;
+
+    Ok(())
+}
+
+// If tenant is not found in the repository, return CloudOnly state
+pub fn get_tenant_state(tenantid: ZTenantId) -> TenantState {
+    let m = access_tenants();
+    match m.get(&tenantid) {
+        Some(tenant) => tenant.state,
+        None => TenantState::CloudOnly,
+    }
+}
+
+pub fn set_tenant_state(tenantid: ZTenantId, newstate: TenantState) -> Result<TenantState> {
+    let mut m = access_tenants();
+    let tenant = m.get_mut(&tenantid);
+
+    match tenant {
+        Some(tenant) => {
+            if newstate == TenantState::Idle && tenant.state != TenantState::Active {
+                // Only Active tenant can become Idle
+                return Ok(tenant.state);
+            }
+            info!("set_tenant_state: {} -> {}", tenant.state, newstate);
+            tenant.state = newstate;
+            Ok(tenant.state)
+        }
+        None => bail!("Tenant not found for tenant {}", tenantid),
+    }
+}
+
+pub fn get_repository_for_tenant(tenantid: ZTenantId) -> Result<Arc<dyn Repository>> {
+    let m = access_tenants();
+    let tenant = m
+        .get(&tenantid)
+        .ok_or_else(|| anyhow!("Tenant not found for tenant {}", tenantid))?;
+
+    match &tenant.repo {
+        Some(repo) => Ok(Arc::clone(repo)),
+        None => anyhow::bail!("Repository for tenant {} is not yet valid", tenantid),
+    }
+}
+
+pub fn get_timeline_for_tenant(
+    tenantid: ZTenantId,
+    timelineid: ZTimelineId,
+) -> Result<Arc<dyn Timeline>> {
+    get_repository_for_tenant(tenantid)?
+        .get_timeline(timelineid)
+        .with_context(|| format!("cannot fetch timeline {}", timelineid))
+}
+
+fn list_tenantids() -> Result<Vec<ZTenantId>> {
+    let m = access_tenants();
+    m.iter()
+        .map(|v| {
+            let (tenantid, _) = v;
+            Ok(*tenantid)
+        })
+        .collect()
+}
+
+#[derive(Serialize, Deserialize, Clone)]
+pub struct TenantInfo {
+    #[serde(with = "hex")]
+    pub id: ZTenantId,
+    pub state: TenantState,
+}
+
+pub fn list_tenants() -> Result<Vec<TenantInfo>> {
+    let m = access_tenants();
+    m.iter()
+        .map(|v| {
+            let (id, tenant) = v;
+            Ok(TenantInfo {
+                id: *id,
+                state: tenant.state,
+            })
+        })
+        .collect()
+}

pageserver/src/tenant_threads.rs

@@ -0,0 +1,149 @@
+//! This module contains functions to serve per-tenant background processes,
+//! such as checkpointer and GC
+use crate::tenant_mgr;
+use crate::tenant_mgr::TenantState;
+use crate::CheckpointConfig;
+use crate::PageServerConf;
+use anyhow::Result;
+use lazy_static::lazy_static;
+use std::collections::HashMap;
+use std::sync::Mutex;
+use std::thread::JoinHandle;
+use std::time::Duration;
+use tracing::*;
+use zenith_metrics::{register_int_gauge_vec, IntGaugeVec};
+use zenith_utils::zid::ZTenantId;
+
+struct TenantHandleEntry {
+    checkpointer_handle: Option<JoinHandle<()>>,
+    gc_handle: Option<JoinHandle<()>>,
+}
+
+// Preserve handles to wait for thread completion
+// at shutdown
+lazy_static! {
+    static ref TENANT_HANDLES: Mutex<HashMap<ZTenantId, TenantHandleEntry>> =
+        Mutex::new(HashMap::new());
+}
+
+lazy_static! {
+    static ref TENANT_THREADS_COUNT: IntGaugeVec = register_int_gauge_vec!(
+        "tenant_threads_count",
+        "Number of live tenant threads",
+        &["tenant_thread_type"]
+    )
+    .expect("failed to define a metric");
+}
+
+// Launch checkpointer and GC for the tenant.
+// It's possible that the threads are running already,
+// if so, just don't spawn new ones.
+pub fn start_tenant_threads(conf: &'static PageServerConf, tenantid: ZTenantId) {
+    let mut handles = TENANT_HANDLES.lock().unwrap();
+    let h = handles
+        .entry(tenantid)
+        .or_insert_with(|| TenantHandleEntry {
+            checkpointer_handle: None,
+            gc_handle: None,
+        });
+
+    if h.checkpointer_handle.is_none() {
+        h.checkpointer_handle = std::thread::Builder::new()
+            .name("Checkpointer thread".into())
+            .spawn(move || {
+                checkpoint_loop(tenantid, conf).expect("Checkpointer thread died");
+            })
+            .ok();
+    }
+
+    if h.gc_handle.is_none() {
+        h.gc_handle = std::thread::Builder::new()
+            .name("GC thread".into())
+            .spawn(move || {
+                gc_loop(tenantid, conf).expect("GC thread died");
+            })
+            .ok();
+    }
+}
+
+pub fn wait_for_tenant_threads_to_stop(tenantid: ZTenantId) {
+    let mut handles = TENANT_HANDLES.lock().unwrap();
+    if let Some(h) = handles.get_mut(&tenantid) {
+        h.checkpointer_handle.take().map(JoinHandle::join);
+        trace!("checkpointer for tenant {} has stopped", tenantid);
+        h.gc_handle.take().map(JoinHandle::join);
+        trace!("gc for tenant {} has stopped", tenantid);
+    }
+    handles.remove(&tenantid);
+}
+
+///
+/// Checkpointer thread's main loop
+///
+fn checkpoint_loop(tenantid: ZTenantId, conf: &'static PageServerConf) -> Result<()> {
+    let gauge = TENANT_THREADS_COUNT.with_label_values(&["checkpointer"]);
+    gauge.inc();
+    scopeguard::defer! {
+        gauge.dec();
+    }
+
+    loop {
+        if tenant_mgr::get_tenant_state(tenantid) != TenantState::Active {
+            break;
+        }
+
+        std::thread::sleep(conf.checkpoint_period);
+        trace!("checkpointer thread for tenant {} waking up", tenantid);
+
+        // checkpoint timelines that have accumulated more than CHECKPOINT_DISTANCE
+        // bytes of WAL since last checkpoint.
+        let repo = tenant_mgr::get_repository_for_tenant(tenantid)?;
+        repo.checkpoint_iteration(CheckpointConfig::Distance(conf.checkpoint_distance))?;
+    }
+
+    trace!(
+        "checkpointer thread stopped for tenant {} state is {}",
+        tenantid,
+        tenant_mgr::get_tenant_state(tenantid)
+    );
+    Ok(())
+}
+
+///
+/// GC thread's main loop
+///
+fn gc_loop(tenantid: ZTenantId, conf: &'static PageServerConf) -> Result<()> {
+    let gauge = TENANT_THREADS_COUNT.with_label_values(&["gc"]);
+    gauge.inc();
+    scopeguard::defer! {
+        gauge.dec();
+    }
+
+    loop {
+        if tenant_mgr::get_tenant_state(tenantid) != TenantState::Active {
+            break;
+        }
+
+        trace!("gc thread for tenant {} waking up", tenantid);
+
+        // Garbage collect old files that are not needed for PITR anymore
+        if conf.gc_horizon > 0 {
+            let repo = tenant_mgr::get_repository_for_tenant(tenantid)?;
+            repo.gc_iteration(None, conf.gc_horizon, false).unwrap();
+        }
+
+        // TODO Write it in more adequate way using
+        // condvar.wait_timeout() or something
+        let mut sleep_time = conf.gc_period.as_secs();
+        while sleep_time > 0 && tenant_mgr::get_tenant_state(tenantid) == TenantState::Active {
+            sleep_time -= 1;
+            std::thread::sleep(Duration::from_secs(1));
+        }
+    }
+    trace!(
+        "GC thread stopped for tenant {} state is {}",
+        tenantid,
+        tenant_mgr::get_tenant_state(tenantid)
+    );
+    Ok(())
+}

pageserver/src/waldecoder.rs

@@ -1,6 +1,6 @@
 //!
 //! WAL decoder. For each WAL record, it decodes the record to figure out which data blocks
-//! the record affects, to add the records to the page cache.
+//! the record affects, so that they can be stored in repository.
 //!
 use bytes::{Buf, BufMut, Bytes, BytesMut};
 use crc32c::*;
@@ -10,28 +10,23 @@ use postgres_ffi::xlog_utils::*;
 use postgres_ffi::XLogLongPageHeaderData;
 use postgres_ffi::XLogPageHeaderData;
 use postgres_ffi::XLogRecord;
-use postgres_ffi::{Oid, TransactionId};
+use postgres_ffi::{BlockNumber, OffsetNumber};
+use postgres_ffi::{MultiXactId, MultiXactOffset, MultiXactStatus, Oid, TransactionId};
 use std::cmp::min;
 use thiserror::Error;
 use zenith_utils::lsn::Lsn;
 
-pub type BlockNumber = u32;
-pub type OffsetNumber = u16;
-pub type MultiXactId = TransactionId;
-pub type MultiXactOffset = u32;
-pub type MultiXactStatus = u32;
-
 #[allow(dead_code)]
 pub struct WalStreamDecoder {
     lsn: Lsn,
 
+    startlsn: Lsn, // LSN where this record starts
     contlen: u32,
     padlen: u32,
 
     inputbuf: BytesMut,
-    recordbuf: BytesMut,
 
-    crc_check: bool,
+    recordbuf: BytesMut,
 }
 
 #[derive(Error, Debug, Clone)]
@@ -46,20 +41,20 @@ pub struct WalDecodeError {
 // FIXME: This isn't a proper rust stream
 //
 impl WalStreamDecoder {
-    pub fn new(lsn: Lsn, crc_check: bool) -> WalStreamDecoder {
+    pub fn new(lsn: Lsn) -> WalStreamDecoder {
         WalStreamDecoder {
             lsn,
 
+            startlsn: Lsn(0),
             contlen: 0,
             padlen: 0,
 
             inputbuf: BytesMut::new(),
             recordbuf: BytesMut::new(),
-
-            crc_check,
         }
     }
 
+    // The latest LSN position fed to the decoder.
     pub fn available(&self) -> Lsn {
         self.lsn + self.inputbuf.remaining() as u64
     }
@@ -77,6 +72,10 @@ impl WalStreamDecoder {
     ///     Err(WalDecodeError): an error occured while decoding, meaning the input was invalid.
     ///
     pub fn poll_decode(&mut self) -> Result<Option<(Lsn, Bytes)>, WalDecodeError> {
+        let recordbuf;
+
+        // Run state machine that validates page headers, and reassembles records
+        // that cross page boundaries.
         loop {
             // parse and verify page boundaries as we go
             if self.lsn.segment_offset(pg_constants::WAL_SEGMENT_SIZE) == 0 {
@@ -97,9 +96,7 @@ impl WalStreamDecoder {
                 // TODO: verify the remaining fields in the header
 
                 self.lsn += XLOG_SIZE_OF_XLOG_LONG_PHD as u64;
-                if !self.crc_check && self.contlen != hdr.std.xlp_rem_len {
-                    self.contlen = hdr.std.xlp_rem_len; // skip continuation record
-                }
+                continue;
             } else if self.lsn.block_offset() == 0 {
                 if self.inputbuf.remaining() < XLOG_SIZE_OF_XLOG_SHORT_PHD {
                     return Ok(None);
@@ -109,19 +106,14 @@ impl WalStreamDecoder {
 
                 if hdr.xlp_pageaddr != self.lsn.0 {
                     return Err(WalDecodeError {
-                        msg: format!(
-                            "invalid xlog page header: xlp_pageaddr={} vs. lsn={}",
-                            hdr.xlp_pageaddr, self.lsn
-                        ),
+                        msg: "invalid xlog page header".into(),
                         lsn: self.lsn,
                     });
                 }
                 // TODO: verify the remaining fields in the header
 
                 self.lsn += XLOG_SIZE_OF_XLOG_SHORT_PHD as u64;
-                if !self.crc_check && self.contlen != hdr.xlp_rem_len {
-                    self.contlen = hdr.xlp_rem_len; // skip continuation record
-                }
+                continue;
             } else if self.padlen > 0 {
                 if self.inputbuf.remaining() < self.padlen as usize {
                     return Ok(None);
@@ -132,27 +124,41 @@ impl WalStreamDecoder {
                 self.lsn += self.padlen as u64;
                 self.padlen = 0;
             } else if self.contlen == 0 {
-                // need to have at least the xl_tot_len field
+                assert!(self.recordbuf.is_empty());
 
+                // need to have at least the xl_tot_len field
                 if self.inputbuf.remaining() < 4 {
                     return Ok(None);
                 }
 
-                // read xl_tot_len FIXME: assumes little-endian
-                let xl_tot_len = self.inputbuf.get_u32_le();
+                // peek xl_tot_len at the beginning of the record.
+                // FIXME: assumes little-endian
+                self.startlsn = self.lsn;
+                let xl_tot_len = (&self.inputbuf[0..4]).get_u32_le();
                 if (xl_tot_len as usize) < XLOG_SIZE_OF_XLOG_RECORD {
                     return Err(WalDecodeError {
                         msg: format!("invalid xl_tot_len {}", xl_tot_len),
                         lsn: self.lsn,
                     });
                 }
-                self.lsn += 4;
 
-                self.recordbuf.clear();
-                self.recordbuf.reserve(xl_tot_len as usize);
-                self.recordbuf.put_u32_le(xl_tot_len);
-
-                self.contlen = xl_tot_len - 4;
+                // Fast path for the common case that the whole record fits on the page.
+                let pageleft = self.lsn.remaining_in_block() as u32;
+                if self.inputbuf.remaining() >= xl_tot_len as usize && xl_tot_len <= pageleft {
+                    // Take the record from the 'inputbuf', and validate it.
+                    recordbuf = self.inputbuf.copy_to_bytes(xl_tot_len as usize);
+                    self.lsn += xl_tot_len as u64;
+                    break;
+                } else {
+                    // Need to assemble the record from pieces. Remember the size of the
+                    // record, and loop back. On next iteration, we will reach the 'else'
+                    // branch below, and copy the part of the record that was on this page
+                    // to 'recordbuf'.  Subsequent iterations will skip page headers, and
+                    // append the continuations from the next pages to 'recordbuf'.
+                    self.recordbuf.reserve(xl_tot_len as usize);
+                    self.contlen = xl_tot_len;
+                    continue;
+                }
             } else {
                 // we're continuing a record, possibly from previous page.
                 let pageleft = self.lsn.remaining_in_block() as u32;
@@ -169,58 +175,47 @@ impl WalStreamDecoder {
                 self.contlen -= n as u32;
 
                 if self.contlen == 0 {
-                    let recordbuf = std::mem::replace(&mut self.recordbuf, BytesMut::new());
-
-                    let recordbuf = recordbuf.freeze();
-                    let mut buf = recordbuf.clone();
-
-                    let xlogrec = XLogRecord::from_bytes(&mut buf);
-
-                    // XLOG_SWITCH records are special. If we see one, we need to skip
-                    // to the next WAL segment.
-                    if xlogrec.is_xlog_switch_record() {
-                        trace!("saw xlog switch record at {}", self.lsn);
-                        self.padlen =
-                            self.lsn.calc_padding(pg_constants::WAL_SEGMENT_SIZE as u64) as u32;
-                    } else {
-                        // Pad to an 8-byte boundary
-                        self.padlen = self.lsn.calc_padding(8u32) as u32;
-                    }
-
-                    // Check record CRC
-                    if self.crc_check {
-                        let mut crc = crc32c_append(0, &recordbuf[XLOG_RECORD_CRC_OFFS + 4..]);
-                        crc = crc32c_append(crc, &recordbuf[0..XLOG_RECORD_CRC_OFFS]);
-                        if crc != xlogrec.xl_crc {
-                            info!("WAL record crc mismatch n={}, buf.len()={}, lsn={}, rec={:?}, recordbuf={:?}",
-								  n, recordbuf.len(), self.lsn, xlogrec, recordbuf);
-                            return Err(WalDecodeError {
-                                msg: format!(
-                                    "WAL record crc mismatch n={}, buf.len()={}, lsn={}, rec={:?}",
-                                    n,
-                                    buf.len(),
-                                    self.lsn,
-                                    xlogrec
-                                ),
-                                lsn: self.lsn,
-                            });
-                        }
-                    }
-
-                    let result = (self.lsn.align(), recordbuf);
-                    return Ok(Some(result));
+                    // The record is now complete.
+                    recordbuf = std::mem::replace(&mut self.recordbuf, BytesMut::new()).freeze();
+                    break;
                 }
+                continue;
             }
         }
-        // check record boundaries
 
-        // deal with continuation records
+        // We now have a record in the 'recordbuf' local variable.
+        let xlogrec = XLogRecord::from_slice(&recordbuf[0..XLOG_SIZE_OF_XLOG_RECORD]);
 
-        // deal with xlog_switch records
+        let mut crc = 0;
+        crc = crc32c_append(crc, &recordbuf[XLOG_RECORD_CRC_OFFS + 4..]);
+        crc = crc32c_append(crc, &recordbuf[0..XLOG_RECORD_CRC_OFFS]);
+        if crc != xlogrec.xl_crc {
+            return Err(WalDecodeError {
+                msg: "WAL record crc mismatch".into(),
+                lsn: self.lsn,
+            });
+        }
+
+        // XLOG_SWITCH records are special. If we see one, we need to skip
+        // to the next WAL segment.
+        if xlogrec.is_xlog_switch_record() {
+            trace!("saw xlog switch record at {}", self.lsn);
+            self.padlen = self.lsn.calc_padding(pg_constants::WAL_SEGMENT_SIZE as u64) as u32;
+        } else {
+            // Pad to an 8-byte boundary
+            self.padlen = self.lsn.calc_padding(8u32) as u32;
+        }
+
+        // Always align resulting LSN on 0x8 boundary -- that is important for getPage()
+        // and WalReceiver integration. Since this code is used both for WalReceiver and
+        // initial WAL import let's force alignment right here.
+        let result = (self.lsn.align(), recordbuf);
+        Ok(Some(result))
     }
 }
 
 #[allow(dead_code)]
+#[derive(Default)]
 pub struct DecodedBkpBlock {
     /* Is this block ref in use? */
     //in_use: bool,
@@ -253,25 +248,7 @@ pub struct DecodedBkpBlock {
 
 impl DecodedBkpBlock {
     pub fn new() -> DecodedBkpBlock {
-        DecodedBkpBlock {
-            rnode_spcnode: 0,
-            rnode_dbnode: 0,
-            rnode_relnode: 0,
-            forknum: 0,
-            blkno: 0,
-
-            flags: 0,
-            has_image: false,
-            apply_image: false,
-            will_init: false,
-            hole_offset: 0,
-            hole_length: 0,
-            bimg_len: 0,
-            bimg_info: 0,
-
-            has_data: false,
-            data_len: 0,
-        }
+        Default::default()
     }
 }
 
@@ -353,6 +330,31 @@ impl XlCreateDatabase {
     }
 }
 
+#[repr(C)]
+#[derive(Debug)]
+pub struct XlDropDatabase {
+    pub db_id: Oid,
+    pub n_tablespaces: Oid, /* number of tablespace IDs */
+    pub tablespace_ids: Vec<Oid>,
+}
+
+impl XlDropDatabase {
+    pub fn decode(buf: &mut Bytes) -> XlDropDatabase {
+        let mut rec = XlDropDatabase {
+            db_id: buf.get_u32_le(),
+            n_tablespaces: buf.get_u32_le(),
+            tablespace_ids: Vec::<Oid>::new(),
+        };
+
+        for _i in 0..rec.n_tablespaces {
+            let id = buf.get_u32_le();
+            rec.tablespace_ids.push(id);
+        }
+
+        rec
+    }
+}
+
 #[repr(C)]
 #[derive(Debug)]
 pub struct XlHeapInsert {
@@ -373,6 +375,7 @@ impl XlHeapInsert {
 #[derive(Debug)]
 pub struct XlHeapMultiInsert {
     pub flags: u8,
+    pub _padding: u8,
     pub ntuples: u16,
 }
 
@@ -380,6 +383,7 @@ impl XlHeapMultiInsert {
     pub fn decode(buf: &mut Bytes) -> XlHeapMultiInsert {
         XlHeapMultiInsert {
             flags: buf.get_u8(),
+            _padding: buf.get_u8(),
             ntuples: buf.get_u16_le(),
         }
     }
@@ -390,6 +394,8 @@ impl XlHeapMultiInsert {
 pub struct XlHeapDelete {
     pub xmax: TransactionId,
     pub offnum: OffsetNumber,
+    pub _padding: u16,
+    pub t_cid: u32,
     pub infobits_set: u8,
     pub flags: u8,
 }
@@ -399,6 +405,8 @@ impl XlHeapDelete {
         XlHeapDelete {
             xmax: buf.get_u32_le(),
             offnum: buf.get_u16_le(),
+            _padding: buf.get_u16_le(),
+            t_cid: buf.get_u32_le(),
             infobits_set: buf.get_u8(),
             flags: buf.get_u8(),
         }
@@ -412,6 +420,7 @@ pub struct XlHeapUpdate {
     pub old_offnum: OffsetNumber,
     pub old_infobits_set: u8,
     pub flags: u8,
+    pub t_cid: u32,
     pub new_xmax: TransactionId,
     pub new_offnum: OffsetNumber,
 }
@@ -423,6 +432,7 @@ impl XlHeapUpdate {
             old_offnum: buf.get_u16_le(),
             old_infobits_set: buf.get_u8(),
             flags: buf.get_u8(),
+            t_cid: buf.get_u32(),
             new_xmax: buf.get_u32_le(),
             new_offnum: buf.get_u16_le(),
         }
@@ -866,6 +876,7 @@ pub fn decode_wal_record(record: Bytes) -> DecodedWALRecord {
         let blkno = blocks[0].blkno / pg_constants::HEAPBLOCKS_PER_PAGE as u32;
         if info == pg_constants::XLOG_HEAP_INSERT {
             let xlrec = XlHeapInsert::decode(&mut buf);
+            assert_eq!(0, buf.remaining());
             if (xlrec.flags
                 & (pg_constants::XLH_INSERT_ALL_VISIBLE_CLEARED
                     | pg_constants::XLH_INSERT_ALL_FROZEN_SET))
@@ -881,6 +892,7 @@ pub fn decode_wal_record(record: Bytes) -> DecodedWALRecord {
             }
         } else if info == pg_constants::XLOG_HEAP_DELETE {
             let xlrec = XlHeapDelete::decode(&mut buf);
+            assert_eq!(0, buf.remaining());
             if (xlrec.flags & pg_constants::XLH_DELETE_ALL_VISIBLE_CLEARED) != 0 {
                 let mut blk = DecodedBkpBlock::new();
                 blk.forknum = pg_constants::VISIBILITYMAP_FORKNUM;
@@ -894,6 +906,9 @@ pub fn decode_wal_record(record: Bytes) -> DecodedWALRecord {
             || info == pg_constants::XLOG_HEAP_HOT_UPDATE
         {
             let xlrec = XlHeapUpdate::decode(&mut buf);
+            // the size of tuple data is inferred from the size of the record.
+            // we can't validate the remaining number of bytes without parsing
+            // the tuple data.
             if (xlrec.flags & pg_constants::XLH_UPDATE_NEW_ALL_VISIBLE_CLEARED) != 0 {
                 let mut blk = DecodedBkpBlock::new();
                 blk.forknum = pg_constants::VISIBILITYMAP_FORKNUM;
@@ -919,6 +934,15 @@ pub fn decode_wal_record(record: Bytes) -> DecodedWALRecord {
         let info = xlogrec.xl_info & pg_constants::XLOG_HEAP_OPMASK;
         if info == pg_constants::XLOG_HEAP2_MULTI_INSERT {
             let xlrec = XlHeapMultiInsert::decode(&mut buf);
+
+            let offset_array_len = if xlogrec.xl_info & pg_constants::XLOG_HEAP_INIT_PAGE > 0 {
+                // the offsets array is omitted if XLOG_HEAP_INIT_PAGE is set
+                0
+            } else {
+                std::mem::size_of::<u16>() * xlrec.ntuples as usize
+            };
+            assert_eq!(offset_array_len, buf.remaining());
+
             if (xlrec.flags
                 & (pg_constants::XLH_INSERT_ALL_VISIBLE_CLEARED
                     | pg_constants::XLH_INSERT_ALL_FROZEN_SET))
@@ -945,3 +969,71 @@ pub fn decode_wal_record(record: Bytes) -> DecodedWALRecord {
         main_data_offset,
     }
 }
+
+///
+/// Build a human-readable string to describe a WAL record
+///
+/// For debugging purposes
+pub fn describe_wal_record(record: &Bytes) -> String {
+    // TODO: It would be nice to use the PostgreSQL rmgrdesc infrastructure for this.
+    // Maybe use the postgres wal redo process, the same used for replaying WAL records?
+    // Or could we compile the rmgrdesc routines into the dump_layer_file() binary directly,
+    // without worrying about security?
+    //
+    // But for now, we have a hand-written code for a few common WAL record types here.
+
+    let mut buf = record.clone();
+
+    // 1. Parse XLogRecord struct
+
+    // FIXME: assume little-endian here
+    let xlogrec = XLogRecord::from_bytes(&mut buf);
+
+    let unknown_str: String;
+
+    let result: &str = match xlogrec.xl_rmid {
+        pg_constants::RM_HEAP2_ID => {
+            let info = xlogrec.xl_info & pg_constants::XLOG_HEAP_OPMASK;
+            match info {
+                pg_constants::XLOG_HEAP2_MULTI_INSERT => "HEAP2 MULTI_INSERT",
+                pg_constants::XLOG_HEAP2_VISIBLE => "HEAP2 VISIBLE",
+                _ => {
+                    unknown_str = format!("HEAP2 UNKNOWN_0x{:02x}", info);
+                    &unknown_str
+                }
+            }
+        }
+        pg_constants::RM_HEAP_ID => {
+            let info = xlogrec.xl_info & pg_constants::XLOG_HEAP_OPMASK;
+            match info {
+                pg_constants::XLOG_HEAP_INSERT => "HEAP INSERT",
+                pg_constants::XLOG_HEAP_DELETE => "HEAP DELETE",
+                pg_constants::XLOG_HEAP_UPDATE => "HEAP UPDATE",
+                pg_constants::XLOG_HEAP_HOT_UPDATE => "HEAP HOT_UPDATE",
+                _ => {
+                    unknown_str = format!("HEAP2 UNKNOWN_0x{:02x}", info);
+                    &unknown_str
+                }
+            }
+        }
+        pg_constants::RM_XLOG_ID => {
+            let info = xlogrec.xl_info & pg_constants::XLR_RMGR_INFO_MASK;
+            match info {
+                pg_constants::XLOG_FPI => "XLOG FPI",
+                pg_constants::XLOG_FPI_FOR_HINT => "XLOG FPI_FOR_HINT",
+                _ => {
+                    unknown_str = format!("XLOG UNKNOWN_0x{:02x}", info);
+                    &unknown_str
+                }
+            }
+        }
+        rmid => {
+            let info = xlogrec.xl_info & pg_constants::XLR_RMGR_INFO_MASK;
+
+            unknown_str = format!("UNKNOWN_RM_{} INFO_0x{:02x}", rmid, info);
+            &unknown_str
+        }
+    };
+
+    String::from(result)
+}

pageserver/src/walreceiver.rs

@@ -1,32 +1,36 @@
 //!
-//! WAL receiver connects to the WAL safekeeper service,
-//! streams WAL, decodes records and saves them in page cache.
+//! WAL receiver connects to the WAL safekeeper service, streams WAL,
+//! decodes records and saves them in the repository for the correct
+//! timeline.
 //!
 //! We keep one WAL receiver active per timeline.
 
-use crate::page_cache;
+use crate::layered_repository;
 use crate::relish::*;
 use crate::restore_local_repo;
+use crate::tenant_mgr;
+use crate::tenant_mgr::TenantState;
+use crate::tenant_threads;
 use crate::waldecoder::*;
-use crate::{PageServerConf, RepositoryFormat};
-use anyhow::{Error, Result};
+use crate::PageServerConf;
+use anyhow::{bail, Error, Result};
 use lazy_static::lazy_static;
-use log::*;
 use postgres::fallible_iterator::FallibleIterator;
 use postgres::replication::ReplicationIter;
 use postgres::{Client, NoTls, SimpleQueryMessage, SimpleQueryRow};
-use postgres_ffi::xlog_utils::*;
 use postgres_ffi::*;
 use postgres_protocol::message::backend::ReplicationMessage;
 use postgres_types::PgLsn;
-use std::cmp::{max, min};
+use std::cell::Cell;
 use std::collections::HashMap;
-use std::fs;
 use std::str::FromStr;
 use std::sync::Mutex;
 use std::thread;
 use std::thread::sleep;
+use std::thread::JoinHandle;
+use std::thread_local;
 use std::time::{Duration, SystemTime};
+use tracing::*;
 use zenith_utils::lsn::Lsn;
 use zenith_utils::zid::ZTenantId;
 use zenith_utils::zid::ZTimelineId;
@@ -36,6 +40,8 @@ use zenith_utils::zid::ZTimelineId;
 //
 struct WalReceiverEntry {
     wal_producer_connstr: String,
+    wal_receiver_handle: Option<JoinHandle<()>>,
+    tenantid: ZTenantId,
 }
 
 lazy_static! {
@@ -43,6 +49,43 @@ lazy_static! {
         Mutex::new(HashMap::new());
 }
 
+thread_local! {
+    // Boolean that is true only for WAL receiver threads
+    //
+    // This is used in `wait_lsn` to guard against usage that might lead to a deadlock.
+    pub(crate) static IS_WAL_RECEIVER: Cell<bool> = Cell::new(false);
+}
+
+// Wait for walreceiver to stop
+// Now it stops when pageserver shutdown is requested.
+// In future we can make this more granular and send shutdown signals
+// per tenant/timeline to cancel inactive walreceivers.
+// TODO deal with blocking pg connections
+pub fn stop_wal_receiver(timelineid: ZTimelineId) {
+    let mut receivers = WAL_RECEIVERS.lock().unwrap();
+    if let Some(r) = receivers.get_mut(&timelineid) {
+        r.wal_receiver_handle.take();
+        // r.wal_receiver_handle.take().map(JoinHandle::join);
+    }
+}
+
+pub fn drop_wal_receiver(timelineid: ZTimelineId, tenantid: ZTenantId) {
+    let mut receivers = WAL_RECEIVERS.lock().unwrap();
+    receivers.remove(&timelineid);
+
+    // Check if it was the last walreceiver of the tenant.
+    // TODO now we store one WalReceiverEntry per timeline,
+    // so this iterator looks a bit strange.
+    for (_timelineid, entry) in receivers.iter() {
+        if entry.tenantid == tenantid {
+            return;
+        }
+    }
+
+    // When last walreceiver of the tenant is gone, change state to Idle
+    tenant_mgr::set_tenant_state(tenantid, TenantState::Idle).unwrap();
+}
+
 // Launch a new WAL receiver, or tell one that's running about change in connection string
 pub fn launch_wal_receiver(
     conf: &'static PageServerConf,
@@ -57,18 +100,24 @@ pub fn launch_wal_receiver(
             receiver.wal_producer_connstr = wal_producer_connstr.into();
         }
         None => {
+            let wal_receiver_handle = thread::Builder::new()
+                .name("WAL receiver thread".into())
+                .spawn(move || {
+                    IS_WAL_RECEIVER.with(|c| c.set(true));
+                    thread_main(conf, timelineid, tenantid);
+                })
+                .unwrap();
+
             let receiver = WalReceiverEntry {
                 wal_producer_connstr: wal_producer_connstr.into(),
+                wal_receiver_handle: Some(wal_receiver_handle),
+                tenantid,
             };
             receivers.insert(timelineid, receiver);
 
-            // Also launch a new thread to handle this connection
-            let _walreceiver_thread = thread::Builder::new()
-                .name("WAL receiver thread".into())
-                .spawn(move || {
-                    thread_main(conf, timelineid, &tenantid);
-                })
-                .unwrap();
+            // Update tenant state and start tenant threads, if they are not running yet.
+            tenant_mgr::set_tenant_state(tenantid, TenantState::Active).unwrap();
+            tenant_threads::start_tenant_threads(conf, tenantid);
         }
     };
 }
@@ -87,17 +136,19 @@ fn get_wal_producer_connstr(timelineid: ZTimelineId) -> String {
 //
 // This is the entry point for the WAL receiver thread.
 //
-fn thread_main(conf: &'static PageServerConf, timelineid: ZTimelineId, tenantid: &ZTenantId) {
-    info!(
-        "WAL receiver thread started for timeline : '{}'",
-        timelineid
-    );
+fn thread_main(conf: &'static PageServerConf, timelineid: ZTimelineId, tenantid: ZTenantId) {
+    let _enter = info_span!("WAL receiver", timeline = %timelineid, tenant = %tenantid).entered();
+    info!("WAL receiver thread started");
+
+    let mut retry_count = 10;
 
     //
     // Make a connection to the WAL safekeeper, or directly to the primary PostgreSQL server,
     // and start streaming WAL from it. If the connection is lost, keep retrying.
+    // TODO How long should we retry in case of losing connection?
+    // Should we retry at all or we can wait for the next callmemaybe request?
     //
-    loop {
+    while !tenant_mgr::shutdown_requested() && retry_count > 0 {
         // Look up the current WAL producer address
         let wal_producer_connstr = get_wal_producer_connstr(timelineid);
 
@@ -108,16 +159,27 @@ fn thread_main(conf: &'static PageServerConf, timelineid: ZTimelineId, tenantid:
                 "WAL streaming connection failed ({}), retrying in 1 second",
                 e
             );
+            retry_count -= 1;
             sleep(Duration::from_secs(1));
+        } else {
+            info!(
+                "walreceiver disconnected tenant {}, timelineid {}",
+                tenantid, timelineid
+            );
+            break;
         }
     }
+    info!("WAL streaming shut down");
+    // Drop it from list of active WAL_RECEIVERS
+    // so that next callmemaybe request launched a new thread
+    drop_wal_receiver(timelineid, tenantid);
 }
 
 fn walreceiver_main(
     conf: &PageServerConf,
     timelineid: ZTimelineId,
     wal_producer_connstr: &str,
-    tenantid: &ZTenantId,
+    tenantid: ZTenantId,
 ) -> Result<(), Error> {
     // Connect to the database in replication mode.
     info!("connecting to {:?}", wal_producer_connstr);
@@ -143,32 +205,26 @@ fn walreceiver_main(
     let end_of_wal = Lsn::from(u64::from(identify.xlogpos));
     let mut caught_up = false;
 
-    let repository = page_cache::get_repository_for_tenant(tenantid)?;
-    let timeline = repository.get_timeline(timelineid).unwrap();
+    let timeline = tenant_mgr::get_timeline_for_tenant(tenantid, timelineid)?;
 
     //
     // Start streaming the WAL, from where we left off previously.
     //
     // If we had previously received WAL up to some point in the middle of a WAL record, we
-    // better start from the end of last full WAL record, not in the middle of one. Hence,
-    // use 'last_record_lsn' rather than 'last_valid_lsn' here.
+    // better start from the end of last full WAL record, not in the middle of one.
     let mut last_rec_lsn = timeline.get_last_record_lsn();
     let mut startpoint = last_rec_lsn;
 
     if startpoint == Lsn(0) {
-        error!("No previous WAL position");
+        bail!("No previous WAL position");
     }
 
     // There might be some padding after the last full record, skip it.
-    //
-    // FIXME: It probably would be better to always start streaming from the beginning
-    // of the page, or the segment, so that we could check the page/segment headers
-    // too. Just for the sake of paranoia.
     startpoint += startpoint.calc_padding(8u32);
 
-    debug!(
-        "last_record_lsn {} starting replication from {} for timeline {}, server is at {}...",
-        last_rec_lsn, startpoint, timelineid, end_of_wal
+    info!(
+        "last_record_lsn {} starting replication from {}, server is at {}...",
+        last_rec_lsn, startpoint, end_of_wal
     );
 
     let query = format!("START_REPLICATION PHYSICAL {}", startpoint);
@@ -176,9 +232,9 @@ fn walreceiver_main(
     let copy_stream = rclient.copy_both_simple(&query)?;
     let mut physical_stream = ReplicationIter::new(copy_stream);
 
-    let mut waldecoder = WalStreamDecoder::new(startpoint, true);
+    let mut waldecoder = WalStreamDecoder::new(startpoint);
 
-    let checkpoint_bytes = timeline.get_page_at_lsn_nowait(RelishTag::Checkpoint, 0, startpoint)?;
+    let checkpoint_bytes = timeline.get_page_at_lsn(RelishTag::Checkpoint, 0, startpoint)?;
     let mut checkpoint = CheckPoint::decode(&checkpoint_bytes)?;
     trace!("CheckPoint.nextXid = {}", checkpoint.nextXid.value);
 
@@ -190,93 +246,49 @@ fn walreceiver_main(
                 let data = xlog_data.data();
                 let startlsn = Lsn::from(xlog_data.wal_start());
                 let endlsn = startlsn + data.len() as u64;
-                let prev_last_rec_lsn = last_rec_lsn;
 
                 trace!("received XLogData between {} and {}", startlsn, endlsn);
+
                 waldecoder.feed_bytes(data);
 
-                loop {
-                    match waldecoder.poll_decode() {
-                        Ok(Some((lsn, recdata))) => {
-                            // Save old checkpoint value to compare with it after decoding WAL record
-                            let old_checkpoint_bytes = checkpoint.encode();
-                            let decoded = decode_wal_record(recdata.clone());
-                            restore_local_repo::save_decoded_record(
-                                &mut checkpoint,
-                                &*timeline,
-                                &decoded,
-                                recdata,
-                                lsn,
-                            )?;
-                            last_rec_lsn = lsn;
+                while let Some((lsn, recdata)) = waldecoder.poll_decode()? {
+                    let _enter = info_span!("processing record", lsn = %lsn).entered();
 
-                            let new_checkpoint_bytes = checkpoint.encode();
-                            // Check if checkpoint data was updated by save_decoded_record
-                            if new_checkpoint_bytes != old_checkpoint_bytes {
-                                timeline.put_page_image(
-                                    RelishTag::Checkpoint,
-                                    0,
-                                    lsn,
-                                    new_checkpoint_bytes,
-                                    false,
-                                )?;
-                            }
-                        }
-                        Ok(None) => {
-                            trace!(
-                                "End of replication stream {}..{} at {}",
-                                startlsn,
-                                endlsn,
-                                last_rec_lsn
-                            );
-                            break;
-                        }
-                        Err(e) => {
-                            info!("Decode error {}", e);
-                            return Err(e.into());
-                        }
-                    }
-                }
-                // Update the last_valid LSN value in the page cache one more time. We updated
-                // it in the loop above, between each WAL record, but we might have received
-                // a partial record after the last completed record. Our page cache's value
-                // better reflect that, because GetPage@LSN requests might also point in the
-                // middle of a record, if the request LSN was taken from the server's current
-                // flush ptr.
-                timeline.advance_last_valid_lsn(endlsn);
+                    // It is important to deal with the aligned records as lsn in getPage@LSN is
+                    // aligned and can be several bytes bigger. Without this alignment we are
+                    // at risk of hittind a deadlock.
+                    assert!(lsn.is_aligned());
 
-                // Somewhat arbitrarily, if we have at least 10 complete wal segments (16 MB each),
-                // "checkpoint" the repository to flush all the changes from WAL we've processed
-                // so far to disk. After this, we don't need the original WAL anymore, and it
-                // can be removed. This is probably too aggressive for production, but it's useful
-                // to expose bugs now.
-                //
-                // TODO: We don't actually dare to remove the WAL. It's useful for debugging,
-                // and we might it for logical decoding other things in the future. Although
-                // we should also be able to fetch it back from the WAL safekeepers or S3 if
-                // needed.
-                if prev_last_rec_lsn.segment_number(pg_constants::WAL_SEGMENT_SIZE)
-                    != last_rec_lsn.segment_number(pg_constants::WAL_SEGMENT_SIZE)
-                {
-                    info!("switched segment {} to {}", prev_last_rec_lsn, last_rec_lsn);
-                    let (oldest_segno, newest_segno) = find_wal_file_range(
-                        conf,
-                        &timelineid,
-                        pg_constants::WAL_SEGMENT_SIZE,
-                        last_rec_lsn,
-                        tenantid,
+                    let writer = timeline.writer();
+
+                    let mut checkpoint_modified = false;
+
+                    let decoded = decode_wal_record(recdata.clone());
+                    restore_local_repo::save_decoded_record(
+                        &mut checkpoint,
+                        &mut checkpoint_modified,
+                        writer.as_ref(),
+                        &decoded,
+                        recdata,
+                        lsn,
                     )?;
 
-                    if newest_segno - oldest_segno >= 10 {
-                        // FIXME: The layered repository performs checkpointing in a separate thread, so this
-                        // isn't needed anymore. Remove 'checkpoint' from the Timeline trait altogether?
-                        if conf.repository_format == RepositoryFormat::RocksDb {
-                            timeline.checkpoint()?;
-                        }
+                    // Check if checkpoint data was updated by save_decoded_record
+                    if checkpoint_modified {
+                        let new_checkpoint_bytes = checkpoint.encode();
 
-                        // TODO: This is where we could remove WAL older than last_rec_lsn.
-                        //remove_wal_files(timelineid, pg_constants::WAL_SEGMENT_SIZE, last_rec_lsn)?;
+                        writer.put_page_image(
+                            RelishTag::Checkpoint,
+                            0,
+                            lsn,
+                            new_checkpoint_bytes,
+                        )?;
                     }
+
+                    // Now that this record has been fully handled, including updating the
+                    // checkpoint data, let the repository know that it is up-to-date to this LSN
+                    writer.advance_last_record_lsn(lsn);
+                    last_rec_lsn = lsn;
                 }
 
                 if !caught_up && endlsn >= end_of_wal {
@@ -284,6 +296,9 @@ fn walreceiver_main(
                     caught_up = true;
                 }
 
+                // Release memory if needed
+                layered_repository::evict_layer_if_needed(conf)?;
+
                 Some(endlsn)
             }
 
@@ -300,7 +315,7 @@ fn walreceiver_main(
                 );
 
                 if reply_requested {
-                    Some(timeline.get_last_valid_lsn())
+                    Some(last_rec_lsn)
                 } else {
                     None
                 }
@@ -312,65 +327,35 @@ fn walreceiver_main(
         if let Some(last_lsn) = status_update {
             // TODO: More thought should go into what values are sent here.
             let last_lsn = PgLsn::from(u64::from(last_lsn));
-            let write_lsn = last_lsn;
+            // We are using disk consistent LSN as `write_lsn`, i.e. LSN at which page server
+            // may guarantee persistence of all received data. Safekeeper is not free to remove
+            // WAL preceding `write_lsn`: it should not be requested by this page server.
+            let write_lsn = PgLsn::from(u64::from(timeline.get_disk_consistent_lsn()));
             let flush_lsn = last_lsn;
             let apply_lsn = PgLsn::from(0);
             let ts = SystemTime::now();
             const NO_REPLY: u8 = 0;
-
             physical_stream.standby_status_update(write_lsn, flush_lsn, apply_lsn, ts, NO_REPLY)?;
         }
+
+        if tenant_mgr::shutdown_requested() {
+            debug!("stop walreceiver because pageserver shutdown is requested");
+            break;
+        }
     }
+
     Ok(())
 }
 
-fn find_wal_file_range(
-    conf: &PageServerConf,
-    timeline: &ZTimelineId,
-    wal_seg_size: usize,
-    written_upto: Lsn,
-    tenant: &ZTenantId,
-) -> Result<(u64, u64)> {
-    let written_upto_segno = written_upto.segment_number(wal_seg_size);
-
-    let mut oldest_segno = written_upto_segno;
-    let mut newest_segno = written_upto_segno;
-    // Scan the wal directory, and count how many WAL filed we could remove
-    let wal_dir = conf.wal_dir_path(timeline, tenant);
-    for entry in fs::read_dir(wal_dir)? {
-        let entry = entry?;
-        let path = entry.path();
-
-        if path.is_dir() {
-            continue;
-        }
-
-        let filename = path.file_name().unwrap().to_str().unwrap();
-
-        if IsXLogFileName(filename) {
-            let (segno, _tli) = XLogFromFileName(filename, wal_seg_size);
-
-            if segno > written_upto_segno {
-                // that's strange.
-                warn!("there is a WAL file from future at {}", path.display());
-                continue;
-            }
-
-            oldest_segno = min(oldest_segno, segno);
-            newest_segno = max(newest_segno, segno);
-        }
-    }
-    // FIXME: would be good to assert that there are no gaps in the WAL files
-
-    Ok((oldest_segno, newest_segno))
-}
-
 /// Data returned from the postgres `IDENTIFY_SYSTEM` command
 ///
 /// See the [postgres docs] for more details.
 ///
 /// [postgres docs]: https://www.postgresql.org/docs/current/protocol-replication.html
 #[derive(Debug)]
+// As of nightly 2021-09-11, fields that are only read by the type's `Debug` impl still count as
+// unused. Relevant issue: https://github.com/rust-lang/rust/issues/88900
+#[allow(dead_code)]
 pub struct IdentifySystem {
     systemid: u64,
     timeline: u32,

pageserver/src/walredo.rs

@@ -22,31 +22,33 @@ use byteorder::{ByteOrder, LittleEndian};
 use bytes::{Buf, BufMut, Bytes, BytesMut};
 use lazy_static::lazy_static;
 use log::*;
-use serde::{Deserialize, Serialize};
-use std::cell::RefCell;
+use nix::poll::*;
+use serde::Serialize;
 use std::fs;
 use std::fs::OpenOptions;
 use std::io::prelude::*;
-use std::io::Error;
+use std::io::{Error, ErrorKind};
+use std::os::unix::io::AsRawFd;
 use std::path::PathBuf;
 use std::process::Stdio;
+use std::process::{Child, ChildStderr, ChildStdin, ChildStdout, Command};
 use std::sync::Mutex;
 use std::time::Duration;
 use std::time::Instant;
-use tokio::io::AsyncBufReadExt;
-use tokio::io::{AsyncReadExt, AsyncWriteExt};
-use tokio::process::{ChildStdin, ChildStdout, Command};
-use tokio::time::timeout;
 use zenith_metrics::{register_histogram, register_int_counter, Histogram, IntCounter};
 use zenith_utils::bin_ser::BeSer;
 use zenith_utils::lsn::Lsn;
+use zenith_utils::nonblock::set_nonblock;
 use zenith_utils::zid::ZTenantId;
 
 use crate::relish::*;
 use crate::repository::WALRecord;
+use crate::waldecoder::XlMultiXactCreate;
 use crate::waldecoder::XlXactParsedRecord;
-use crate::waldecoder::{MultiXactId, XlMultiXactCreate};
 use crate::PageServerConf;
+use postgres_ffi::nonrelfile_utils::mx_offset_to_flags_bitshift;
+use postgres_ffi::nonrelfile_utils::mx_offset_to_flags_offset;
+use postgres_ffi::nonrelfile_utils::mx_offset_to_member_offset;
 use postgres_ffi::nonrelfile_utils::transaction_id_set_status;
 use postgres_ffi::pg_constants;
 use postgres_ffi::XLogRecord;
@@ -57,7 +59,7 @@ use postgres_ffi::XLogRecord;
 /// In Postgres `BufferTag` structure is used for exactly the same purpose.
 /// [See more related comments here](https://github.com/postgres/postgres/blob/99c5852e20a0987eca1c38ba0c09329d4076b6a0/src/include/storage/buf_internals.h#L91).
 ///
-#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Clone, Copy, Serialize, Deserialize)]
+#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Clone, Copy, Serialize)]
 pub struct BufferTag {
     pub rel: RelTag,
     pub blknum: u32,
@@ -80,7 +82,7 @@ pub trait WalRedoManager: Send + Sync {
         blknum: u32,
         lsn: Lsn,
         base_img: Option<Bytes>,
-        records: Vec<WALRecord>,
+        records: Vec<(Lsn, WALRecord)>,
     ) -> Result<Bytes, WalRedoError>;
 }
 
@@ -97,7 +99,7 @@ impl crate::walredo::WalRedoManager for DummyRedoManager {
         _blknum: u32,
         _lsn: Lsn,
         _base_img: Option<Bytes>,
-        _records: Vec<WALRecord>,
+        _records: Vec<(Lsn, WALRecord)>,
     ) -> Result<Bytes, WalRedoError> {
         Err(WalRedoError::InvalidState)
     }
@@ -137,7 +139,6 @@ pub struct PostgresRedoManager {
     tenantid: ZTenantId,
     conf: &'static PageServerConf,
 
-    runtime: tokio::runtime::Runtime,
     process: Mutex<Option<PostgresRedoProcess>>,
 }
 
@@ -148,9 +149,16 @@ struct WalRedoRequest {
     lsn: Lsn,
 
     base_img: Option<Bytes>,
-    records: Vec<WALRecord>,
+    records: Vec<(Lsn, WALRecord)>,
 }
 
+impl WalRedoRequest {
+    // Can this request be served by zenith redo funcitons
+    // or we need to pass it to wal-redo postgres process?
+    fn can_apply_in_zenith(&self) -> bool {
+        !matches!(self.rel, RelishTag::Relation(_))
+    }
+}
 /// An error happened in WAL redo
 #[derive(Debug, thiserror::Error)]
 pub enum WalRedoError {
@@ -159,6 +167,8 @@ pub enum WalRedoError {
 
     #[error("cannot perform WAL redo now")]
     InvalidState,
+    #[error("cannot perform WAL redo for this request")]
+    InvalidRequest,
 }
 
 ///
@@ -177,10 +187,9 @@ impl WalRedoManager for PostgresRedoManager {
         blknum: u32,
         lsn: Lsn,
         base_img: Option<Bytes>,
-        records: Vec<WALRecord>,
+        records: Vec<(Lsn, WALRecord)>,
     ) -> Result<Bytes, WalRedoError> {
         let start_time;
-        let lock_time;
         let end_time;
 
         let request = WalRedoRequest {
@@ -192,65 +201,49 @@ impl WalRedoManager for PostgresRedoManager {
         };
 
         start_time = Instant::now();
-        let result = {
+        let result;
+
+        if request.can_apply_in_zenith() {
+            result = self.handle_apply_request_zenith(&request);
+
+            end_time = Instant::now();
+            WAL_REDO_TIME.observe(end_time.duration_since(start_time).as_secs_f64());
+        } else {
             let mut process_guard = self.process.lock().unwrap();
-            lock_time = Instant::now();
+            let lock_time = Instant::now();
 
             // launch the WAL redo process on first use
             if process_guard.is_none() {
-                let p = self
-                    .runtime
-                    .block_on(PostgresRedoProcess::launch(self.conf, &self.tenantid))?;
+                let p = PostgresRedoProcess::launch(self.conf, &self.tenantid)?;
                 *process_guard = Some(p);
             }
-            let process = (*process_guard).as_ref().unwrap();
+            let process = process_guard.as_mut().unwrap();
 
-            self.runtime
-                .block_on(self.handle_apply_request(&process, &request))
-        };
-        end_time = Instant::now();
+            result = self.handle_apply_request_postgres(process, &request);
 
-        WAL_REDO_WAIT_TIME.observe(lock_time.duration_since(start_time).as_secs_f64());
-        WAL_REDO_TIME.observe(end_time.duration_since(lock_time).as_secs_f64());
+            WAL_REDO_WAIT_TIME.observe(lock_time.duration_since(start_time).as_secs_f64());
+            end_time = Instant::now();
+            WAL_REDO_TIME.observe(end_time.duration_since(lock_time).as_secs_f64());
+
+            // If something went wrong, don't try to reuse the process. Kill it, and
+            // next request will launch a new one.
+            if result.is_err() {
+                let process = process_guard.take().unwrap();
+                process.kill();
+            }
+        }
 
         result
     }
 }
 
-fn mx_offset_to_flags_offset(xid: MultiXactId) -> usize {
-    ((xid / pg_constants::MULTIXACT_MEMBERS_PER_MEMBERGROUP as u32) as u16
-        % pg_constants::MULTIXACT_MEMBERGROUPS_PER_PAGE
-        * pg_constants::MULTIXACT_MEMBERGROUP_SIZE) as usize
-}
-
-fn mx_offset_to_flags_bitshift(xid: MultiXactId) -> u16 {
-    (xid as u16) % pg_constants::MULTIXACT_MEMBERS_PER_MEMBERGROUP
-        * pg_constants::MXACT_MEMBER_BITS_PER_XACT
-}
-
-/* Location (byte offset within page) of TransactionId of given member */
-fn mx_offset_to_member_offset(xid: MultiXactId) -> usize {
-    mx_offset_to_flags_offset(xid)
-        + (pg_constants::MULTIXACT_FLAGBYTES_PER_GROUP
-            + (xid as u16 % pg_constants::MULTIXACT_MEMBERS_PER_MEMBERGROUP) * 4) as usize
-}
-
 impl PostgresRedoManager {
     ///
     /// Create a new PostgresRedoManager.
     ///
     pub fn new(conf: &'static PageServerConf, tenantid: ZTenantId) -> PostgresRedoManager {
-        // We block on waiting for requests on the walredo request channel, but
-        // use async I/O to communicate with the child process. Initialize the
-        // runtime for the async part.
-        let runtime = tokio::runtime::Builder::new_current_thread()
-            .enable_all()
-            .build()
-            .unwrap();
-
         // The actual process is launched lazily, on first request.
         PostgresRedoManager {
-            runtime,
             tenantid,
             conf,
             process: Mutex::new(None),
@@ -258,13 +251,47 @@ impl PostgresRedoManager {
     }
 
     ///
-    /// Process one request for WAL redo.
+    /// Process one request for WAL redo using wal-redo postgres
     ///
-    async fn handle_apply_request(
+    fn handle_apply_request_postgres(
         &self,
-        process: &PostgresRedoProcess,
+        process: &mut PostgresRedoProcess,
         request: &WalRedoRequest,
     ) -> Result<Bytes, WalRedoError> {
+        let blknum = request.blknum;
+        let lsn = request.lsn;
+        let base_img = request.base_img.clone();
+        let records = &request.records;
+        let nrecords = records.len();
+
+        let start = Instant::now();
+
+        let apply_result: Result<Bytes, Error>;
+
+        if let RelishTag::Relation(rel) = request.rel {
+            // Relational WAL records are applied using wal-redo-postgres
+            let buf_tag = BufferTag { rel, blknum };
+            apply_result = process.apply_wal_records(buf_tag, base_img, records);
+
+            let duration = start.elapsed();
+
+            debug!(
+                "postgres applied {} WAL records in {} us to reconstruct page image at LSN {}",
+                nrecords,
+                duration.as_micros(),
+                lsn
+            );
+
+            apply_result.map_err(WalRedoError::IoError)
+        } else {
+            Err(WalRedoError::InvalidRequest)
+        }
+    }
+
+    ///
+    /// Process one request for WAL redo using custom zenith code
+    ///
+    fn handle_apply_request_zenith(&self, request: &WalRedoRequest) -> Result<Bytes, WalRedoError> {
         let rel = request.rel;
         let blknum = request.blknum;
         let lsn = request.lsn;
@@ -276,181 +303,158 @@ impl PostgresRedoManager {
         let start = Instant::now();
 
         let apply_result: Result<Bytes, Error>;
-        if let RelishTag::Relation(rel) = rel {
-            // Relational WAL records are applied using wal-redo-postgres
-            let buf_tag = BufferTag { rel, blknum };
-            apply_result = process.apply_wal_records(buf_tag, base_img, records).await;
+
+        // Non-relational WAL records are handled here, with custom code that has the
+        // same effects as the corresponding Postgres WAL redo function.
+        const ZERO_PAGE: [u8; 8192] = [0u8; 8192];
+        let mut page = BytesMut::new();
+        if let Some(fpi) = base_img {
+            // If full-page image is provided, then use it...
+            page.extend_from_slice(&fpi[..]);
         } else {
-            // Non-relational WAL records are handled here, with custom code that has the
-            // same effects as the corresponding Postgres WAL redo function.
-            const ZERO_PAGE: [u8; 8192] = [0u8; 8192];
-            let mut page = BytesMut::new();
-            if let Some(fpi) = base_img {
-                // If full-page image is provided, then use it...
-                page.extend_from_slice(&fpi[..]);
-            } else {
-                // otherwise initialize page with zeros
-                page.extend_from_slice(&ZERO_PAGE);
+            // otherwise initialize page with zeros
+            page.extend_from_slice(&ZERO_PAGE);
+        }
+        // Apply all collected WAL records
+        for (_lsn, record) in records {
+            let mut buf = Bytes::from(record.rec().to_vec());
+
+            WAL_REDO_RECORD_COUNTER.inc();
+
+            // 1. Parse XLogRecord struct
+            // FIXME: refactor to avoid code duplication.
+            let xlogrec = XLogRecord::from_bytes(&mut buf);
+
+            //move to main data
+            // TODO probably, we should store some records in our special format
+            // to avoid this weird parsing on replay
+            let skip = (record.main_data_offset() - pg_constants::SIZEOF_XLOGRECORD) as usize;
+            if buf.remaining() > skip {
+                buf.advance(skip);
             }
-            // Apply all collected WAL records
-            for record in records {
-                let mut buf = record.rec.clone();
 
-                WAL_REDO_RECORD_COUNTER.inc();
-
-                // 1. Parse XLogRecord struct
-                // FIXME: refactor to avoid code duplication.
-                let xlogrec = XLogRecord::from_bytes(&mut buf);
-
-                //move to main data
-                // TODO probably, we should store some records in our special format
-                // to avoid this weird parsing on replay
-                let skip = (record.main_data_offset - pg_constants::SIZEOF_XLOGRECORD) as usize;
-                if buf.remaining() > skip {
-                    buf.advance(skip);
-                }
-
-                if xlogrec.xl_rmid == pg_constants::RM_XACT_ID {
-                    // Transaction manager stuff
-                    let rec_segno = match rel {
-                        RelishTag::Slru { slru, segno } => {
-                            if slru != SlruKind::Clog {
-                                panic!("Not valid XACT relish tag {:?}", rel);
-                            }
-                            segno
-                        }
-                        _ => panic!("Not valid XACT relish tag {:?}", rel),
-                    };
-                    let parsed_xact =
-                        XlXactParsedRecord::decode(&mut buf, xlogrec.xl_xid, xlogrec.xl_info);
-                    if parsed_xact.info == pg_constants::XLOG_XACT_COMMIT
-                        || parsed_xact.info == pg_constants::XLOG_XACT_COMMIT_PREPARED
-                    {
-                        transaction_id_set_status(
-                            parsed_xact.xid,
-                            pg_constants::TRANSACTION_STATUS_COMMITTED,
-                            &mut page,
+            if xlogrec.xl_rmid == pg_constants::RM_XACT_ID {
+                // Transaction manager stuff
+                let rec_segno = match rel {
+                    RelishTag::Slru { slru, segno } => {
+                        assert!(
+                            slru == SlruKind::Clog,
+                            "Not valid XACT relish tag {:?}",
+                            rel
                         );
-                        for subxact in &parsed_xact.subxacts {
-                            let pageno = *subxact as u32 / pg_constants::CLOG_XACTS_PER_PAGE;
-                            let segno = pageno / pg_constants::SLRU_PAGES_PER_SEGMENT;
-                            let rpageno = pageno % pg_constants::SLRU_PAGES_PER_SEGMENT;
-                            // only update xids on the requested page
-                            if rec_segno == segno && blknum == rpageno {
-                                transaction_id_set_status(
-                                    *subxact,
-                                    pg_constants::TRANSACTION_STATUS_SUB_COMMITTED,
-                                    &mut page,
-                                );
-                            }
-                        }
-                    } else if parsed_xact.info == pg_constants::XLOG_XACT_ABORT
-                        || parsed_xact.info == pg_constants::XLOG_XACT_ABORT_PREPARED
-                    {
-                        transaction_id_set_status(
-                            parsed_xact.xid,
-                            pg_constants::TRANSACTION_STATUS_ABORTED,
-                            &mut page,
-                        );
-                        for subxact in &parsed_xact.subxacts {
-                            let pageno = *subxact as u32 / pg_constants::CLOG_XACTS_PER_PAGE;
-                            let segno = pageno / pg_constants::SLRU_PAGES_PER_SEGMENT;
-                            let rpageno = pageno % pg_constants::SLRU_PAGES_PER_SEGMENT;
-                            // only update xids on the requested page
-                            if rec_segno == segno && blknum == rpageno {
-                                transaction_id_set_status(
-                                    *subxact,
-                                    pg_constants::TRANSACTION_STATUS_ABORTED,
-                                    &mut page,
-                                );
-                            }
+                        segno
+                    }
+                    _ => panic!("Not valid XACT relish tag {:?}", rel),
+                };
+                let parsed_xact =
+                    XlXactParsedRecord::decode(&mut buf, xlogrec.xl_xid, xlogrec.xl_info);
+                if parsed_xact.info == pg_constants::XLOG_XACT_COMMIT
+                    || parsed_xact.info == pg_constants::XLOG_XACT_COMMIT_PREPARED
+                {
+                    transaction_id_set_status(
+                        parsed_xact.xid,
+                        pg_constants::TRANSACTION_STATUS_COMMITTED,
+                        &mut page,
+                    );
+                    for subxact in &parsed_xact.subxacts {
+                        let pageno = *subxact as u32 / pg_constants::CLOG_XACTS_PER_PAGE;
+                        let segno = pageno / pg_constants::SLRU_PAGES_PER_SEGMENT;
+                        let rpageno = pageno % pg_constants::SLRU_PAGES_PER_SEGMENT;
+                        // only update xids on the requested page
+                        if rec_segno == segno && blknum == rpageno {
+                            transaction_id_set_status(
+                                *subxact,
+                                pg_constants::TRANSACTION_STATUS_COMMITTED,
+                                &mut page,
+                            );
                         }
                     }
-                } else if xlogrec.xl_rmid == pg_constants::RM_MULTIXACT_ID {
-                    // Multixact operations
-                    let info = xlogrec.xl_info & pg_constants::XLR_RMGR_INFO_MASK;
-                    if info == pg_constants::XLOG_MULTIXACT_CREATE_ID {
-                        let xlrec = XlMultiXactCreate::decode(&mut buf);
-                        if let RelishTag::Slru {
-                            slru,
-                            segno: rec_segno,
-                        } = rel
-                        {
-                            if slru == SlruKind::MultiXactMembers {
-                                for i in 0..xlrec.nmembers {
-                                    let pageno =
-                                        i / pg_constants::MULTIXACT_MEMBERS_PER_PAGE as u32;
-                                    let segno = pageno / pg_constants::SLRU_PAGES_PER_SEGMENT;
-                                    let rpageno = pageno % pg_constants::SLRU_PAGES_PER_SEGMENT;
-                                    if segno == rec_segno && rpageno == blknum {
-                                        // update only target block
-                                        let offset = xlrec.moff + i;
-                                        let memberoff = mx_offset_to_member_offset(offset);
-                                        let flagsoff = mx_offset_to_flags_offset(offset);
-                                        let bshift = mx_offset_to_flags_bitshift(offset);
-                                        let mut flagsval =
-                                            LittleEndian::read_u32(&page[flagsoff..flagsoff + 4]);
-                                        flagsval &= !(((1
-                                            << pg_constants::MXACT_MEMBER_BITS_PER_XACT)
-                                            - 1)
+                } else if parsed_xact.info == pg_constants::XLOG_XACT_ABORT
+                    || parsed_xact.info == pg_constants::XLOG_XACT_ABORT_PREPARED
+                {
+                    transaction_id_set_status(
+                        parsed_xact.xid,
+                        pg_constants::TRANSACTION_STATUS_ABORTED,
+                        &mut page,
+                    );
+                    for subxact in &parsed_xact.subxacts {
+                        let pageno = *subxact as u32 / pg_constants::CLOG_XACTS_PER_PAGE;
+                        let segno = pageno / pg_constants::SLRU_PAGES_PER_SEGMENT;
+                        let rpageno = pageno % pg_constants::SLRU_PAGES_PER_SEGMENT;
+                        // only update xids on the requested page
+                        if rec_segno == segno && blknum == rpageno {
+                            transaction_id_set_status(
+                                *subxact,
+                                pg_constants::TRANSACTION_STATUS_ABORTED,
+                                &mut page,
+                            );
+                        }
+                    }
+                }
+            } else if xlogrec.xl_rmid == pg_constants::RM_MULTIXACT_ID {
+                // Multixact operations
+                let info = xlogrec.xl_info & pg_constants::XLR_RMGR_INFO_MASK;
+                if info == pg_constants::XLOG_MULTIXACT_CREATE_ID {
+                    let xlrec = XlMultiXactCreate::decode(&mut buf);
+                    if let RelishTag::Slru {
+                        slru,
+                        segno: rec_segno,
+                    } = rel
+                    {
+                        if slru == SlruKind::MultiXactMembers {
+                            for i in 0..xlrec.nmembers {
+                                let pageno = i / pg_constants::MULTIXACT_MEMBERS_PER_PAGE as u32;
+                                let segno = pageno / pg_constants::SLRU_PAGES_PER_SEGMENT;
+                                let rpageno = pageno % pg_constants::SLRU_PAGES_PER_SEGMENT;
+                                if segno == rec_segno && rpageno == blknum {
+                                    // update only target block
+                                    let offset = xlrec.moff + i;
+                                    let memberoff = mx_offset_to_member_offset(offset);
+                                    let flagsoff = mx_offset_to_flags_offset(offset);
+                                    let bshift = mx_offset_to_flags_bitshift(offset);
+                                    let mut flagsval =
+                                        LittleEndian::read_u32(&page[flagsoff..flagsoff + 4]);
+                                    flagsval &=
+                                        !(((1 << pg_constants::MXACT_MEMBER_BITS_PER_XACT) - 1)
                                             << bshift);
-                                        flagsval |= xlrec.members[i as usize].status << bshift;
-                                        LittleEndian::write_u32(
-                                            &mut page[flagsoff..flagsoff + 4],
-                                            flagsval,
-                                        );
-                                        LittleEndian::write_u32(
-                                            &mut page[memberoff..memberoff + 4],
-                                            xlrec.members[i as usize].xid,
-                                        );
-                                    }
+                                    flagsval |= xlrec.members[i as usize].status << bshift;
+                                    LittleEndian::write_u32(
+                                        &mut page[flagsoff..flagsoff + 4],
+                                        flagsval,
+                                    );
+                                    LittleEndian::write_u32(
+                                        &mut page[memberoff..memberoff + 4],
+                                        xlrec.members[i as usize].xid,
+                                    );
                                 }
-                            } else {
-                                // Multixact offsets SLRU
-                                let offs = (xlrec.mid
-                                    % pg_constants::MULTIXACT_OFFSETS_PER_PAGE as u32
-                                    * 4) as usize;
-                                LittleEndian::write_u32(&mut page[offs..offs + 4], xlrec.moff);
                             }
                         } else {
-                            panic!();
+                            // Multixact offsets SLRU
+                            let offs = (xlrec.mid % pg_constants::MULTIXACT_OFFSETS_PER_PAGE as u32
+                                * 4) as usize;
+                            LittleEndian::write_u32(&mut page[offs..offs + 4], xlrec.moff);
                         }
                     } else {
                         panic!();
                     }
-                } else if xlogrec.xl_rmid == pg_constants::RM_RELMAP_ID {
-                    // Relation map file has size 512 bytes
-                    page.clear();
-                    page.extend_from_slice(&buf[12..]); // skip xl_relmap_update
-                    assert!(page.len() == 512); // size of pg_filenode.map
+                } else {
+                    panic!();
                 }
             }
-
-            apply_result = Ok::<Bytes, Error>(page.freeze());
         }
 
+        apply_result = Ok::<Bytes, Error>(page.freeze());
+
         let duration = start.elapsed();
 
-        let result: Result<Bytes, WalRedoError>;
-
         debug!(
-            "applied {} WAL records in {} ms to reconstruct page image at LSN {}",
+            "zenith applied {} WAL records in {} ms to reconstruct page image at LSN {}",
             nrecords,
             duration.as_millis(),
             lsn
         );
 
-        if let Err(e) = apply_result {
-            error!("could not apply WAL records: {}", e);
-            result = Err(WalRedoError::IoError(e));
-        } else {
-            let img = apply_result.unwrap();
-
-            result = Ok(img);
-        }
-
-        // The caller is responsible for sending the response
-        result
+        apply_result.map_err(WalRedoError::IoError)
     }
 }
 
@@ -458,28 +462,27 @@ impl PostgresRedoManager {
 /// Handle to the Postgres WAL redo process
 ///
 struct PostgresRedoProcess {
-    stdin: RefCell<ChildStdin>,
-    stdout: RefCell<ChildStdout>,
+    child: Child,
+    stdin: ChildStdin,
+    stdout: ChildStdout,
+    stderr: ChildStderr,
 }
 
 impl PostgresRedoProcess {
     //
     // Start postgres binary in special WAL redo mode.
     //
-    async fn launch(
-        conf: &PageServerConf,
-        tenantid: &ZTenantId,
-    ) -> Result<PostgresRedoProcess, Error> {
+    fn launch(conf: &PageServerConf, tenantid: &ZTenantId) -> Result<PostgresRedoProcess, Error> {
         // FIXME: We need a dummy Postgres cluster to run the process in. Currently, we
         // just create one with constant name. That fails if you try to launch more than
         // one WAL redo manager concurrently.
-        let datadir = conf.tenant_path(&tenantid).join("wal-redo-datadir");
+        let datadir = conf.tenant_path(tenantid).join("wal-redo-datadir");
 
         // Create empty data directory for wal-redo postgres, deleting old one first.
         if datadir.exists() {
             info!("directory {:?} exists, removing", &datadir);
             if let Err(e) = fs::remove_dir_all(&datadir) {
-                error!("could not remove old wal-redo-datadir: {:?}", e);
+                error!("could not remove old wal-redo-datadir: {:#}", e);
             }
         }
         info!("running initdb in {:?}", datadir.display());
@@ -490,7 +493,6 @@ impl PostgresRedoProcess {
             .env("LD_LIBRARY_PATH", conf.pg_lib_dir().to_str().unwrap())
             .env("DYLD_LIBRARY_PATH", conf.pg_lib_dir().to_str().unwrap())
             .output()
-            .await
             .expect("failed to execute initdb");
 
         if !initdb.status.success() {
@@ -527,110 +529,139 @@ impl PostgresRedoProcess {
             datadir.display()
         );
 
-        let stdin = child.stdin.take().expect("failed to open child's stdin");
-        let stderr = child.stderr.take().expect("failed to open child's stderr");
-        let stdout = child.stdout.take().expect("failed to open child's stdout");
+        let stdin = child.stdin.take().unwrap();
+        let stdout = child.stdout.take().unwrap();
+        let stderr = child.stderr.take().unwrap();
 
-        // This async block reads the child's stderr, and forwards it to the logger
-        let f_stderr = async {
-            let mut stderr_buffered = tokio::io::BufReader::new(stderr);
-
-            let mut line = String::new();
-            loop {
-                let res = stderr_buffered.read_line(&mut line).await;
-                if res.is_err() {
-                    debug!("could not convert line to utf-8");
-                    continue;
-                }
-                if res.unwrap() == 0 {
-                    break;
-                }
-                error!("wal-redo-postgres: {}", line.trim());
-                line.clear();
-            }
-            Ok::<(), Error>(())
-        };
-        tokio::spawn(f_stderr);
+        set_nonblock(stdin.as_raw_fd())?;
+        set_nonblock(stdout.as_raw_fd())?;
+        set_nonblock(stderr.as_raw_fd())?;
 
         Ok(PostgresRedoProcess {
-            stdin: RefCell::new(stdin),
-            stdout: RefCell::new(stdout),
+            child,
+            stdin,
+            stdout,
+            stderr,
         })
     }
 
+    fn kill(mut self) {
+        let _ = self.child.kill();
+        if let Ok(exit_status) = self.child.wait() {
+            error!("wal-redo-postgres exited with code {}", exit_status);
+        }
+        drop(self);
+    }
+
     //
     // Apply given WAL records ('records') over an old page image. Returns
     // new page image.
     //
-    async fn apply_wal_records(
-        &self,
+    fn apply_wal_records(
+        &mut self,
         tag: BufferTag,
         base_img: Option<Bytes>,
-        records: &[WALRecord],
+        records: &[(Lsn, WALRecord)],
     ) -> Result<Bytes, std::io::Error> {
-        let mut stdin = self.stdin.borrow_mut();
-        let mut stdout = self.stdout.borrow_mut();
+        // Serialize all the messages to send the WAL redo process first.
+        //
+        // This could be problematic if there are millions of records to replay,
+        // but in practice the number of records is usually so small that it doesn't
+        // matter, and it's better to keep this code simple.
+        let mut writebuf: Vec<u8> = Vec::new();
+        build_begin_redo_for_block_msg(tag, &mut writebuf);
+        if let Some(img) = base_img {
+            build_push_page_msg(tag, &img, &mut writebuf);
+        }
+        for (lsn, rec) in records.iter() {
+            build_apply_record_msg(*lsn, rec.rec(), &mut writebuf);
+        }
+        build_get_page_msg(tag, &mut writebuf);
+        WAL_REDO_RECORD_COUNTER.inc_by(records.len() as u64);
+
+        // The input is now in 'writebuf'. Do a blind write first, writing as much as
+        // we can, before calling poll(). That skips one call to poll() if the stdin is
+        // already available for writing, which it almost certainly is because the
+        // process is idle.
+        let mut nwrite = self.stdin.write(&writebuf)?;
+
+        // We expect the WAL redo process to respond with an 8k page image. We read it
+        // into this buffer.
+        let mut resultbuf = vec![0; pg_constants::BLCKSZ.into()];
+        let mut nresult: usize = 0; // # of bytes read into 'resultbuf' so far
+
+        // Prepare for calling poll()
+        let mut pollfds = [
+            PollFd::new(self.stdout.as_raw_fd(), PollFlags::POLLIN),
+            PollFd::new(self.stderr.as_raw_fd(), PollFlags::POLLIN),
+            PollFd::new(self.stdin.as_raw_fd(), PollFlags::POLLOUT),
+        ];
 
         // We do three things simultaneously: send the old base image and WAL records to
         // the child process's stdin, read the result from child's stdout, and forward any logging
         // information that the child writes to its stderr to the page server's log.
-        //
-        // 'f_stdin' handles writing the base image and WAL records to the child process.
-        // 'f_stdout' below reads the result back. And 'f_stderr', which was spawned into the
-        // tokio runtime in the 'launch' function already, forwards the logging.
-        let f_stdin = async {
-            // Send base image, if any. (If the record initializes the page, previous page
-            // version is not needed.)
-            timeout(
-                TIMEOUT,
-                stdin.write_all(&build_begin_redo_for_block_msg(tag)),
-            )
-            .await??;
-            if base_img.is_some() {
-                timeout(
-                    TIMEOUT,
-                    stdin.write_all(&build_push_page_msg(tag, base_img.unwrap())),
-                )
-                .await??;
+        while nresult < pg_constants::BLCKSZ.into() {
+            // If we have more data to write, wake up if 'stdin' becomes writeable or
+            // we have data to read. Otherwise only wake up if there's data to read.
+            let nfds = if nwrite < writebuf.len() { 3 } else { 2 };
+            let n = nix::poll::poll(&mut pollfds[0..nfds], TIMEOUT.as_millis() as i32)?;
+
+            if n == 0 {
+                return Err(Error::new(ErrorKind::Other, "WAL redo timed out"));
             }
 
-            // Send WAL records.
-            for rec in records.iter() {
-                let r = rec.clone();
+            // If we have some messages in stderr, forward them to the log.
+            let err_revents = pollfds[1].revents().unwrap();
+            if err_revents & (PollFlags::POLLERR | PollFlags::POLLIN) != PollFlags::empty() {
+                let mut errbuf: [u8; 16384] = [0; 16384];
+                let n = self.stderr.read(&mut errbuf)?;
 
-                WAL_REDO_RECORD_COUNTER.inc();
+                // The message might not be split correctly into lines here. But this is
+                // good enough, the important thing is to get the message to the log.
+                if n > 0 {
+                    error!(
+                        "wal-redo-postgres: {}",
+                        String::from_utf8_lossy(&errbuf[0..n])
+                    );
 
-                stdin
-                    .write_all(&build_apply_record_msg(r.lsn, r.rec))
-                    .await?;
-
-                //debug!("sent WAL record to wal redo postgres process ({:X}/{:X}",
-                //       r.lsn >> 32, r.lsn & 0xffff_ffff);
+                    // To make sure we capture all log from the process if it fails, keep
+                    // reading from the stderr, before checking the stdout.
+                    continue;
+                }
+            } else if err_revents.contains(PollFlags::POLLHUP) {
+                return Err(Error::new(
+                    ErrorKind::BrokenPipe,
+                    "WAL redo process closed its stderr unexpectedly",
+                ));
             }
-            //debug!("sent {} WAL records to wal redo postgres process ({:X}/{:X}",
-            //       records.len(), lsn >> 32, lsn & 0xffff_ffff);
 
-            // Send GetPage command to get the result back
-            timeout(TIMEOUT, stdin.write_all(&build_get_page_msg(tag))).await??;
-            timeout(TIMEOUT, stdin.flush()).await??;
-            //debug!("sent GetPage for {}", tag.blknum);
-            Ok::<(), Error>(())
-        };
+            // If we have more data to write and 'stdin' is writeable, do write.
+            if nwrite < writebuf.len() {
+                let in_revents = pollfds[2].revents().unwrap();
+                if in_revents & (PollFlags::POLLERR | PollFlags::POLLOUT) != PollFlags::empty() {
+                    nwrite += self.stdin.write(&writebuf[nwrite..])?;
+                } else if in_revents.contains(PollFlags::POLLHUP) {
+                    // We still have more data to write, but the process closed the pipe.
+                    return Err(Error::new(
+                        ErrorKind::BrokenPipe,
+                        "WAL redo process closed its stdin unexpectedly",
+                    ));
+                }
+            }
 
-        // Read back new page image
-        let f_stdout = async {
-            let mut buf = [0u8; 8192];
+            // If we have some data in stdout, read it to the result buffer.
+            let out_revents = pollfds[0].revents().unwrap();
+            if out_revents & (PollFlags::POLLERR | PollFlags::POLLIN) != PollFlags::empty() {
+                nresult += self.stdout.read(&mut resultbuf[nresult..])?;
+            } else if out_revents.contains(PollFlags::POLLHUP) {
+                return Err(Error::new(
+                    ErrorKind::BrokenPipe,
+                    "WAL redo process closed its stdout unexpectedly",
+                ));
+            }
+        }
 
-            timeout(TIMEOUT, stdout.read_exact(&mut buf)).await??;
-            //debug!("got response for {}", tag.blknum);
-            Ok::<[u8; 8192], Error>(buf)
-        };
-
-        let res = tokio::try_join!(f_stdout, f_stdin)?;
-
-        let buf = res.0;
-
-        Ok::<Bytes, Error>(Bytes::from(std::vec::Vec::from(buf)))
+        Ok(Bytes::from(resultbuf))
     }
 }
 
@@ -638,81 +669,42 @@ impl PostgresRedoProcess {
 // process. See vendor/postgres/src/backend/tcop/zenith_wal_redo.c for
 // explanation of the protocol.
 
-fn build_begin_redo_for_block_msg(tag: BufferTag) -> Bytes {
+fn build_begin_redo_for_block_msg(tag: BufferTag, buf: &mut Vec<u8>) {
     let len = 4 + 1 + 4 * 4;
-    let mut buf = BytesMut::with_capacity(1 + len);
 
     buf.put_u8(b'B');
     buf.put_u32(len as u32);
 
-    // FIXME: this is a temporary hack that should go away when we refactor
-    // the postgres protocol serialization + handlers.
-    //
-    // BytesMut is a dynamic growable buffer, used a lot in tokio code but
-    // not in the std library. To write to a BytesMut from a serde serializer,
-    // we need to either:
-    // - pre-allocate the required buffer space. This is annoying because we
-    //   shouldn't care what the exact serialized size is-- that's the
-    //   serializer's job.
-    // - Or, we need to create a temporary "writer" (which implements the
-    //   `Write` trait). It's a bit awkward, because the writer consumes the
-    //   underlying BytesMut, and we need to extract it later with
-    //   `into_inner`.
-    let mut writer = buf.writer();
-    tag.ser_into(&mut writer)
+    tag.ser_into(buf)
         .expect("serialize BufferTag should always succeed");
-    let buf = writer.into_inner();
-
-    debug_assert!(buf.len() == 1 + len);
-
-    buf.freeze()
 }
 
-fn build_push_page_msg(tag: BufferTag, base_img: Bytes) -> Bytes {
+fn build_push_page_msg(tag: BufferTag, base_img: &[u8], buf: &mut Vec<u8>) {
     assert!(base_img.len() == 8192);
 
     let len = 4 + 1 + 4 * 4 + base_img.len();
-    let mut buf = BytesMut::with_capacity(1 + len);
 
     buf.put_u8(b'P');
     buf.put_u32(len as u32);
-    let mut writer = buf.writer();
-    tag.ser_into(&mut writer)
+    tag.ser_into(buf)
         .expect("serialize BufferTag should always succeed");
-    let mut buf = writer.into_inner();
     buf.put(base_img);
-
-    debug_assert!(buf.len() == 1 + len);
-
-    buf.freeze()
 }
 
-fn build_apply_record_msg(endlsn: Lsn, rec: Bytes) -> Bytes {
+fn build_apply_record_msg(endlsn: Lsn, rec: &[u8], buf: &mut Vec<u8>) {
     let len = 4 + 8 + rec.len();
-    let mut buf = BytesMut::with_capacity(1 + len);
 
     buf.put_u8(b'A');
     buf.put_u32(len as u32);
     buf.put_u64(endlsn.0);
     buf.put(rec);
-
-    debug_assert!(buf.len() == 1 + len);
-
-    buf.freeze()
 }
 
-fn build_get_page_msg(tag: BufferTag) -> Bytes {
+fn build_get_page_msg(tag: BufferTag, buf: &mut Vec<u8>) {
     let len = 4 + 1 + 4 * 4;
-    let mut buf = BytesMut::with_capacity(1 + len);
 
     buf.put_u8(b'G');
     buf.put_u32(len as u32);
-    let mut writer = buf.writer();
-    tag.ser_into(&mut writer)
+    tag.ser_into(buf)
         .expect("serialize BufferTag should always succeed");
-    let buf = writer.into_inner();
-
-    debug_assert!(buf.len() == 1 + len);
-
-    buf.freeze()
 }

postgres_ffi/Cargo.toml

@@ -19,8 +19,9 @@ lazy_static = "1.4"
 log = "0.4.14"
 memoffset = "0.6.2"
 thiserror = "1.0"
+serde = { version = "1.0", features = ["derive"] }
 workspace_hack = { path = "../workspace_hack" }
 zenith_utils = { path = "../zenith_utils" }
 
 [build-dependencies]
-bindgen = "0.57"
+bindgen = "0.59.1"

postgres_ffi/README

@@ -13,11 +13,6 @@ in each major PostgreSQL version. Currently, this module is based on
 PostgreSQL v14, but in the future we will probably need a separate
 copy for each PostgreSQL version.
 
-To interact with the C structs, there is some unsafe code in this
-module. Do not copy-paste that to the rest of the codebase! Keep the
-amount of unsafe code to a minimum, and limited to this module only,
-and only where it's truly needed.
-
 TODO: Currently, there is also some code that deals with WAL records
 in pageserver/src/waldecoder.rs.  That should be moved into this
 module. The rest of the codebase should not have intimate knowledge of

postgres_ffi/build.rs

@@ -3,6 +3,44 @@ extern crate bindgen;
 use std::env;
 use std::path::PathBuf;
 
+use bindgen::callbacks::ParseCallbacks;
+
+#[derive(Debug)]
+struct PostgresFfiCallbacks;
+
+impl ParseCallbacks for PostgresFfiCallbacks {
+    fn include_file(&self, filename: &str) {
+        // This does the equivalent of passing bindgen::CargoCallbacks
+        // to the builder .parse_callbacks() method.
+        let cargo_callbacks = bindgen::CargoCallbacks;
+        cargo_callbacks.include_file(filename)
+    }
+
+    // Add any custom #[derive] attributes to the data structures that bindgen
+    // creates.
+    fn add_derives(&self, name: &str) -> Vec<String> {
+        // This is the list of data structures that we want to serialize/deserialize.
+        let serde_list = [
+            "XLogRecord",
+            "XLogPageHeaderData",
+            "XLogLongPageHeaderData",
+            "CheckPoint",
+            "FullTransactionId",
+            "ControlFileData",
+        ];
+
+        if serde_list.contains(&name) {
+            vec![
+                "Default".into(), // Default allows us to easily fill the padding fields with 0.
+                "Serialize".into(),
+                "Deserialize".into(),
+            ]
+        } else {
+            vec![]
+        }
+    }
+}
+
 fn main() {
     // Tell cargo to invalidate the built crate whenever the wrapper changes
     println!("cargo:rerun-if-changed=pg_control_ffi.h");
@@ -19,20 +57,28 @@ fn main() {
         // Tell cargo to invalidate the built crate whenever any of the
         // included header files changed.
         //
-        .parse_callbacks(Box::new(bindgen::CargoCallbacks))
+        .parse_callbacks(Box::new(PostgresFfiCallbacks))
         //
         // These are the types and constants that we want to generate bindings for
         //
-        .whitelist_type("ControlFileData")
-        .whitelist_type("CheckPoint")
-        .whitelist_type("FullTransactionId")
-        .whitelist_type("XLogRecord")
-        .whitelist_type("XLogPageHeaderData")
-        .whitelist_type("XLogLongPageHeaderData")
-        .whitelist_var("XLOG_PAGE_MAGIC")
-        .whitelist_var("PG_CONTROL_FILE_SIZE")
-        .whitelist_var("PG_CONTROLFILEDATA_OFFSETOF_CRC")
-        .whitelist_type("DBState")
+        .allowlist_type("BlockNumber")
+        .allowlist_type("OffsetNumber")
+        .allowlist_type("MultiXactId")
+        .allowlist_type("MultiXactOffset")
+        .allowlist_type("MultiXactStatus")
+        .allowlist_type("ControlFileData")
+        .allowlist_type("CheckPoint")
+        .allowlist_type("FullTransactionId")
+        .allowlist_type("XLogRecord")
+        .allowlist_type("XLogPageHeaderData")
+        .allowlist_type("XLogLongPageHeaderData")
+        .allowlist_var("XLOG_PAGE_MAGIC")
+        .allowlist_var("PG_CONTROL_FILE_SIZE")
+        .allowlist_var("PG_CONTROLFILEDATA_OFFSETOF_CRC")
+        .allowlist_type("DBState")
+        // Because structs are used for serialization, tell bindgen to emit
+        // explicit padding fields.
+        .explicit_padding(true)
         //
         // Path the server include dir. It is in tmp_install/include/server, if you did
         // "configure --prefix=<path to tmp_install>". But if you used "configure --prefix=/",

postgres_ffi/pg_control_ffi.h

@@ -8,3 +8,6 @@
 #include "catalog/pg_control.h"
 #include "access/xlog_internal.h"
 
+#include "storage/block.h"
+#include "storage/off.h"
+#include "access/multixact.h"

postgres_ffi/src/controlfile_utils.rs

@@ -11,7 +11,7 @@
 //! data directory is compatible with a postgres binary. That includes
 //! a version number, configuration options that can be set at
 //! compilation time like the block size, and the platform's alignment
-//! and endianess information. (The PostgreSQL on-disk file format is
+//! and endianness information. (The PostgreSQL on-disk file format is
 //! not portable across platforms.)
 //!
 //! The control file is stored in the PostgreSQL data directory, as
@@ -43,6 +43,8 @@ impl ControlFileData {
     /// Interpret a slice of bytes as a Postgres control file.
     ///
     pub fn decode(buf: &[u8]) -> Result<ControlFileData> {
+        use zenith_utils::bin_ser::LeSer;
+
         // Check that the slice has the expected size. The control file is
         // padded with zeros up to a 512 byte sector size, so accept a
         // larger size too, so that the caller can just the whole file
@@ -55,26 +57,8 @@ impl ControlFileData {
         let OFFSETOF_CRC = Self::pg_control_crc_offset();
         let expectedcrc = crc32c::crc32c(&buf[0..OFFSETOF_CRC]);
 
-        // Convert the slice into an array of the right size, and use `transmute` to
-        // reinterpret the raw bytes as a ControlFileData struct.
-        //
-        // NB: Ideally we would use 'zerocopy::FromBytes' for this, but bindgen doesn't
-        // derive FromBytes for us. The safety of this depends on the same constraints
-        // as for FromBytes, namely, all of its fields must implement FromBytes. That
-        // includes the primitive integer types, like `u8`, `u16`, `u32`, `u64` and their
-        // signed variants. But `bool` is not safe, because the contents of the high bits
-        // in a rust bool are undefined. In practice, PostgreSQL uses 1 to represent
-        // true and 0 for false, which is compatible with Rust bool, but let's try not to
-        // depend on it.
-        //
-        // FIXME: ControlFileData does contain 'bool's at the moment.
-        //
-        // See https://github.com/zenithdb/zenith/issues/207 for discussion on the safety
-        // of this.
-        let mut b: [u8; SIZEOF_CONTROLDATA] = [0u8; SIZEOF_CONTROLDATA];
-        b.copy_from_slice(&buf[0..SIZEOF_CONTROLDATA]);
-        let controlfile: ControlFileData =
-            unsafe { std::mem::transmute::<[u8; SIZEOF_CONTROLDATA], ControlFileData>(b) };
+        // Use serde to deserialize the input as a ControlFileData struct.
+        let controlfile = ControlFileData::des_prefix(buf)?;
 
         // Check the CRC
         if expectedcrc != controlfile.crc {
@@ -93,21 +77,10 @@ impl ControlFileData {
     ///
     /// The CRC is recomputed to match the contents of the fields.
     pub fn encode(&self) -> Bytes {
-        //
-        // Use `transmute` to reinterpret struct as raw bytes.
-        //
-        // FIXME: This triggers undefined behavior, because the contents
-        // of the padding bytes are undefined, and this leaks those
-        // undefined bytes into the resulting array. The Rust code won't
-        // care what's in those bytes, and PostgreSQL doesn't care
-        // either. HOWEVER, it is a potential security issue, because the
-        // bytes can contain arbitrary pieces of memory from the page
-        // server. In the worst case, that could be private keys or
-        // another tenant's data.
-        //
-        // See https://github.com/zenithdb/zenith/issues/207 for discussion.
-        let b: [u8; SIZEOF_CONTROLDATA] =
-            unsafe { std::mem::transmute::<ControlFileData, [u8; SIZEOF_CONTROLDATA]>(*self) };
+        use zenith_utils::bin_ser::LeSer;
+
+        // Serialize into a new buffer.
+        let b = self.ser().unwrap();
 
         // Recompute the CRC
         let OFFSETOF_CRC = Self::pg_control_crc_offset();

postgres_ffi/src/lib.rs

@@ -4,6 +4,9 @@
 // suppress warnings on rust 1.53 due to bindgen unit tests.
 // https://github.com/rust-lang/rust-bindgen/issues/1651
 #![allow(deref_nullptr)]
+
+use serde::{Deserialize, Serialize};
+
 include!(concat!(env!("OUT_DIR"), "/bindings.rs"));
 
 pub mod controlfile_utils;
@@ -11,3 +14,23 @@ pub mod nonrelfile_utils;
 pub mod pg_constants;
 pub mod relfile_utils;
 pub mod xlog_utils;
+
+//  See TransactionIdIsNormal in transam.h
+pub const fn transaction_id_is_normal(id: TransactionId) -> bool {
+    id > pg_constants::FIRST_NORMAL_TRANSACTION_ID
+}
+
+// See TransactionIdPrecedes in transam.c
+pub const fn transaction_id_precedes(id1: TransactionId, id2: TransactionId) -> bool {
+    /*
+     * If either ID is a permanent XID then we can just do unsigned
+     * comparison.  If both are normal, do a modulo-2^32 comparison.
+     */
+
+    if !(transaction_id_is_normal(id1)) || !transaction_id_is_normal(id2) {
+        return id1 < id2;
+    }
+
+    let diff = id1.wrapping_sub(id2) as i32;
+    diff < 0
+}

postgres_ffi/src/nonrelfile_utils.rs

@@ -1,10 +1,12 @@
 //!
 //! Common utilities for dealing with PostgreSQL non-relation files.
 //!
-use crate::pg_constants;
+use crate::{pg_constants, transaction_id_precedes};
 use bytes::BytesMut;
 use log::*;
 
+use crate::MultiXactId;
+
 pub fn transaction_id_set_status(xid: u32, status: u8, page: &mut BytesMut) {
     trace!(
         "handle_apply_request for RM_XACT_ID-{} (1-commit, 2-abort, 3-sub_commit)",
@@ -30,3 +32,51 @@ pub fn transaction_id_get_status(xid: u32, page: &[u8]) -> u8 {
 
     ((page[byteno] >> bshift) & pg_constants::CLOG_XACT_BITMASK) as u8
 }
+
+// See CLOGPagePrecedes in clog.c
+pub const fn clogpage_precedes(page1: u32, page2: u32) -> bool {
+    let mut xid1 = page1 * pg_constants::CLOG_XACTS_PER_PAGE;
+    xid1 += pg_constants::FIRST_NORMAL_TRANSACTION_ID + 1;
+    let mut xid2 = page2 * pg_constants::CLOG_XACTS_PER_PAGE;
+    xid2 += pg_constants::FIRST_NORMAL_TRANSACTION_ID + 1;
+
+    transaction_id_precedes(xid1, xid2)
+        && transaction_id_precedes(xid1, xid2 + pg_constants::CLOG_XACTS_PER_PAGE - 1)
+}
+
+// See SlruMayDeleteSegment() in slru.c
+pub fn slru_may_delete_clogsegment(segpage: u32, cutoff_page: u32) -> bool {
+    let seg_last_page = segpage + pg_constants::SLRU_PAGES_PER_SEGMENT - 1;
+
+    assert_eq!(segpage % pg_constants::SLRU_PAGES_PER_SEGMENT, 0);
+
+    clogpage_precedes(segpage, cutoff_page) && clogpage_precedes(seg_last_page, cutoff_page)
+}
+
+// Multixact utils
+
+pub fn mx_offset_to_flags_offset(xid: MultiXactId) -> usize {
+    ((xid / pg_constants::MULTIXACT_MEMBERS_PER_MEMBERGROUP as u32) as u16
+        % pg_constants::MULTIXACT_MEMBERGROUPS_PER_PAGE
+        * pg_constants::MULTIXACT_MEMBERGROUP_SIZE) as usize
+}
+
+pub fn mx_offset_to_flags_bitshift(xid: MultiXactId) -> u16 {
+    (xid as u16) % pg_constants::MULTIXACT_MEMBERS_PER_MEMBERGROUP
+        * pg_constants::MXACT_MEMBER_BITS_PER_XACT
+}
+
+/* Location (byte offset within page) of TransactionId of given member */
+pub fn mx_offset_to_member_offset(xid: MultiXactId) -> usize {
+    mx_offset_to_flags_offset(xid)
+        + (pg_constants::MULTIXACT_FLAGBYTES_PER_GROUP
+            + (xid as u16 % pg_constants::MULTIXACT_MEMBERS_PER_MEMBERGROUP) * 4) as usize
+}
+
+fn mx_offset_to_member_page(xid: u32) -> u32 {
+    xid / pg_constants::MULTIXACT_MEMBERS_PER_PAGE as u32
+}
+
+pub fn mx_offset_to_member_segment(xid: u32) -> i32 {
+    (mx_offset_to_member_page(xid) / pg_constants::SLRU_PAGES_PER_SEGMENT) as i32
+}

postgres_ffi/src/pg_constants.rs

@@ -87,11 +87,14 @@ pub const XACT_XINFO_HAS_TWOPHASE: u32 = 1u32 << 4;
 pub const XLOG_NEXTOID: u8 = 0x30;
 pub const XLOG_SWITCH: u8 = 0x40;
 pub const XLOG_SMGR_TRUNCATE: u8 = 0x20;
+pub const XLOG_FPI_FOR_HINT: u8 = 0xA0;
+pub const XLOG_FPI: u8 = 0xB0;
 pub const DB_SHUTDOWNED: u32 = 1;
 
 // From multixact.h
 pub const FIRST_MULTIXACT_ID: u32 = 1;
 pub const MAX_MULTIXACT_ID: u32 = 0xFFFFFFFF;
+pub const MAX_MULTIXACT_OFFSET: u32 = 0xFFFFFFFF;
 
 pub const XLOG_MULTIXACT_ZERO_OFF_PAGE: u8 = 0x00;
 pub const XLOG_MULTIXACT_ZERO_MEM_PAGE: u8 = 0x10;
@@ -116,6 +119,7 @@ pub const XLOG_HEAP_INSERT: u8 = 0x00;
 pub const XLOG_HEAP_DELETE: u8 = 0x10;
 pub const XLOG_HEAP_UPDATE: u8 = 0x20;
 pub const XLOG_HEAP_HOT_UPDATE: u8 = 0x40;
+pub const XLOG_HEAP_INIT_PAGE: u8 = 0x80;
 pub const XLOG_HEAP2_VISIBLE: u8 = 0x40;
 pub const XLOG_HEAP2_MULTI_INSERT: u8 = 0x50;
 pub const XLH_INSERT_ALL_FROZEN_SET: u8 = (1 << 5) as u8;
@@ -185,11 +189,11 @@ pub const XLOG_CHECKPOINT_SHUTDOWN: u8 = 0x00;
 pub const XLOG_CHECKPOINT_ONLINE: u8 = 0x10;
 pub const XLP_LONG_HEADER: u16 = 0x0002;
 
-pub const PG_MAJORVERSION: &'static str = "14";
+pub const PG_MAJORVERSION: &str = "14";
 
 // List of subdirectories inside pgdata.
 // Copied from src/bin/initdb/initdb.c
-pub const PGDATA_SUBDIRS: [&'static str; 22] = [
+pub const PGDATA_SUBDIRS: [&str; 22] = [
     "global",
     "pg_wal/archive_status",
     "pg_commit_ts",
@@ -214,11 +218,11 @@ pub const PGDATA_SUBDIRS: [&'static str; 22] = [
     "pg_logical/mappings",
 ];
 
-pub const PGDATA_SPECIAL_FILES: [&'static str; 4] = [
-    "pg_hba.conf",
-    "pg_ident.conf",
-    "postgresql.conf",
-    "postgresql.auto.conf",
-];
+// Don't include postgresql.conf as it is inconvenient on node start:
+// we need postgresql.conf before basebackup to synchronize safekeepers
+// so no point in overwriting it during backup restore. Rest of the files
+// here are not needed before backup so it is okay to edit them after.
+pub const PGDATA_SPECIAL_FILES: [&str; 3] =
+    ["pg_hba.conf", "pg_ident.conf", "postgresql.auto.conf"];
 
-pub static PG_HBA: &'static str = include_str!("../samples/pg_hba.conf");
+pub static PG_HBA: &str = include_str!("../samples/pg_hba.conf");

postgres_ffi/src/xlog_utils.rs

@@ -9,23 +9,26 @@
 
 use crate::pg_constants;
 use crate::CheckPoint;
-use crate::ControlFileData;
 use crate::FullTransactionId;
 use crate::XLogLongPageHeaderData;
 use crate::XLogPageHeaderData;
 use crate::XLogRecord;
 use crate::XLOG_PAGE_MAGIC;
 
+use anyhow::{bail, Result};
 use byteorder::{ByteOrder, LittleEndian};
+use bytes::BytesMut;
 use bytes::{Buf, Bytes};
-use bytes::{BufMut, BytesMut};
 use crc32c::*;
 use log::*;
+use std::cmp::max;
 use std::cmp::min;
 use std::fs::{self, File};
 use std::io::prelude::*;
+use std::io::SeekFrom;
 use std::path::{Path, PathBuf};
 use std::time::SystemTime;
+use zenith_utils::lsn::Lsn;
 
 pub const XLOG_FNAME_LEN: usize = 24;
 pub const XLOG_BLCKSZ: usize = 8192;
@@ -37,6 +40,7 @@ pub const MAX_SEND_SIZE: usize = XLOG_BLCKSZ * 16;
 pub const XLOG_SIZE_OF_XLOG_SHORT_PHD: usize = std::mem::size_of::<XLogPageHeaderData>();
 pub const XLOG_SIZE_OF_XLOG_LONG_PHD: usize = std::mem::size_of::<XLogLongPageHeaderData>();
 pub const XLOG_SIZE_OF_XLOG_RECORD: usize = std::mem::size_of::<XLogRecord>();
+#[allow(clippy::identity_op)]
 pub const SIZE_OF_XLOG_RECORD_DATA_HEADER_SHORT: usize = 1 * 2;
 
 pub type XLogRecPtr = u64;
@@ -88,6 +92,21 @@ pub fn IsPartialXLogFileName(fname: &str) -> bool {
     fname.ends_with(".partial") && IsXLogFileName(&fname[0..fname.len() - 8])
 }
 
+/// If LSN points to the beginning of the page, then shift it to first record,
+/// otherwise align on 8-bytes boundary (required for WAL records)
+pub fn normalize_lsn(lsn: Lsn, seg_sz: usize) -> Lsn {
+    if lsn.0 % XLOG_BLCKSZ as u64 == 0 {
+        let hdr_size = if lsn.0 % seg_sz as u64 == 0 {
+            XLOG_SIZE_OF_XLOG_LONG_PHD
+        } else {
+            XLOG_SIZE_OF_XLOG_SHORT_PHD
+        };
+        lsn + hdr_size as u64
+    } else {
+        lsn.align()
+    }
+}
+
 pub fn get_current_timestamp() -> TimestampTz {
     const UNIX_EPOCH_JDATE: u64 = 2440588; /* == date2j(1970, 1, 1) */
     const POSTGRES_EPOCH_JDATE: u64 = 2451545; /* == date2j(2000, 1, 1) */
@@ -108,129 +127,131 @@ fn find_end_of_wal_segment(
     segno: XLogSegNo,
     tli: TimeLineID,
     wal_seg_size: usize,
-    is_partial: bool,
-    rec_offs: &mut usize,
-    rec_hdr: &mut [u8; XLOG_SIZE_OF_XLOG_RECORD],
-    crc: &mut u32,
-    check_contrec: bool,
-) -> u32 {
-    let mut offs: usize = 0;
+    start_offset: usize, // start reading at this point
+) -> Result<u32> {
+    // step back to the beginning of the page to read it in...
+    let mut offs: usize = start_offset - start_offset % XLOG_BLCKSZ;
     let mut contlen: usize = 0;
+    let mut wal_crc: u32 = 0;
+    let mut crc: u32 = 0;
+    let mut rec_offs: usize = 0;
     let mut buf = [0u8; XLOG_BLCKSZ];
     let file_name = XLogFileName(tli, segno, wal_seg_size);
     let mut last_valid_rec_pos: usize = 0;
-    let file_path = data_dir.join(if is_partial {
-        file_name.clone() + ".partial"
-    } else {
-        file_name
-    });
-    let mut file = File::open(&file_path).unwrap();
+    let mut file = File::open(data_dir.join(file_name.clone() + ".partial")).unwrap();
+    file.seek(SeekFrom::Start(offs as u64))?;
+    let mut rec_hdr = [0u8; XLOG_RECORD_CRC_OFFS];
 
     while offs < wal_seg_size {
+        // we are at the beginning of the page; read it in
         if offs % XLOG_BLCKSZ == 0 {
-            if let Ok(bytes_read) = file.read(&mut buf) {
-                if bytes_read != buf.len() {
-                    break;
-                }
-            } else {
-                break;
+            let bytes_read = file.read(&mut buf)?;
+            if bytes_read != buf.len() {
+                bail!(
+                    "failed to read {} bytes from {} at {}",
+                    XLOG_BLCKSZ,
+                    file_name,
+                    offs
+                );
             }
+
             let xlp_magic = LittleEndian::read_u16(&buf[0..2]);
             let xlp_info = LittleEndian::read_u16(&buf[2..4]);
             let xlp_rem_len = LittleEndian::read_u32(&buf[XLP_REM_LEN_OFFS..XLP_REM_LEN_OFFS + 4]);
+            // this is expected in current usage when valid WAL starts after page header
             if xlp_magic != XLOG_PAGE_MAGIC as u16 {
-                info!("Invalid WAL file {:?} magic {}", &file_path, xlp_magic);
-                break;
+                trace!(
+                    "invalid WAL file {}.partial magic {} at {:?}",
+                    file_name,
+                    xlp_magic,
+                    Lsn(XLogSegNoOffsetToRecPtr(segno, offs as u32, wal_seg_size)),
+                );
             }
             if offs == 0 {
                 offs = XLOG_SIZE_OF_XLOG_LONG_PHD;
                 if (xlp_info & XLP_FIRST_IS_CONTRECORD) != 0 {
-                    if check_contrec {
-                        let xl_tot_len = LittleEndian::read_u32(&rec_hdr[0..4]) as usize;
-                        contlen = xlp_rem_len as usize;
-                        if *rec_offs + contlen < xl_tot_len
-                            || (*rec_offs + contlen != xl_tot_len
-                                && contlen != XLOG_BLCKSZ - XLOG_SIZE_OF_XLOG_LONG_PHD)
-                        {
-                            info!(
-                                "Corrupted continuation record: offs={}, contlen={}, xl_tot_len={}",
-                                *rec_offs, contlen, xl_tot_len
-                            );
-                            return 0;
-                        }
-                    } else {
-                        offs += ((xlp_rem_len + 7) & !7) as usize;
-                    }
-                } else if *rec_offs != 0 {
-                    // There is incompleted page at previous segment but no cont record:
-                    // it means that current segment is not valid and we have to return back.
-                    info!("CONTRECORD flag is missed in page header");
-                    return 0;
+                    offs += ((xlp_rem_len + 7) & !7) as usize;
                 }
             } else {
                 offs += XLOG_SIZE_OF_XLOG_SHORT_PHD;
             }
+            // ... and step forward again if asked
+            offs = max(offs, start_offset);
+
+        // beginning of the next record
         } else if contlen == 0 {
             let page_offs = offs % XLOG_BLCKSZ;
             let xl_tot_len = LittleEndian::read_u32(&buf[page_offs..page_offs + 4]) as usize;
             if xl_tot_len == 0 {
-                break;
+                info!(
+                    "find_end_of_wal_segment reached zeros at {:?}",
+                    Lsn(XLogSegNoOffsetToRecPtr(segno, offs as u32, wal_seg_size))
+                );
+                break; // zeros, reached the end
             }
+            last_valid_rec_pos = offs;
             offs += 4;
-            *rec_offs = 4;
+            rec_offs = 4;
             contlen = xl_tot_len - 4;
             rec_hdr[0..4].copy_from_slice(&buf[page_offs..page_offs + 4]);
         } else {
-            let page_offs = offs % XLOG_BLCKSZ;
             // we're continuing a record, possibly from previous page.
+            let page_offs = offs % XLOG_BLCKSZ;
             let pageleft = XLOG_BLCKSZ - page_offs;
 
             // read the rest of the record, or as much as fits on this page.
             let n = min(contlen, pageleft);
-            let mut hdr_len: usize = 0;
-            if *rec_offs < XLOG_SIZE_OF_XLOG_RECORD {
-                // copy header
-                hdr_len = min(XLOG_SIZE_OF_XLOG_RECORD - *rec_offs, n);
-                rec_hdr[*rec_offs..*rec_offs + hdr_len]
-                    .copy_from_slice(&buf[page_offs..page_offs + hdr_len]);
+            // fill rec_hdr (header up to (but not including) xl_crc field)
+            if rec_offs < XLOG_RECORD_CRC_OFFS {
+                let len = min(XLOG_RECORD_CRC_OFFS - rec_offs, n);
+                rec_hdr[rec_offs..rec_offs + len].copy_from_slice(&buf[page_offs..page_offs + len]);
             }
-            *crc = crc32c_append(*crc, &buf[page_offs + hdr_len..page_offs + n]);
-            *rec_offs += n;
+            if rec_offs <= XLOG_RECORD_CRC_OFFS && rec_offs + n >= XLOG_SIZE_OF_XLOG_RECORD {
+                let crc_offs = page_offs - rec_offs + XLOG_RECORD_CRC_OFFS;
+                wal_crc = LittleEndian::read_u32(&buf[crc_offs..crc_offs + 4]);
+                crc = crc32c_append(0, &buf[crc_offs + 4..page_offs + n]);
+            } else {
+                crc ^= 0xFFFFFFFFu32;
+                crc = crc32c_append(crc, &buf[page_offs..page_offs + n]);
+            }
+            crc = !crc;
+            rec_offs += n;
             offs += n;
             contlen -= n;
 
             if contlen == 0 {
-                *crc = crc32c_append(*crc, &rec_hdr[0..XLOG_RECORD_CRC_OFFS]);
+                crc = !crc;
+                crc = crc32c_append(crc, &rec_hdr);
                 offs = (offs + 7) & !7; // pad on 8 bytes boundary */
-                let wal_crc = LittleEndian::read_u32(
-                    &rec_hdr[XLOG_RECORD_CRC_OFFS..XLOG_RECORD_CRC_OFFS + 4],
-                );
-                if *crc == wal_crc {
+                if crc == wal_crc {
+                    // record is valid, advance the result to its end (with
+                    // alignment to the next record taken into account)
                     last_valid_rec_pos = offs;
-                    // Reset rec_offs and crc for start of new record
-                    *rec_offs = 0;
-                    *crc = 0;
                 } else {
                     info!(
-                        "CRC mismatch {} vs {} at offset {} lsn {}",
-                        *crc, wal_crc, offs, last_valid_rec_pos
+                        "CRC mismatch {} vs {} at {}",
+                        crc, wal_crc, last_valid_rec_pos
                     );
                     break;
                 }
             }
         }
     }
-    last_valid_rec_pos as u32
+    Ok(last_valid_rec_pos as u32)
 }
 
 ///
 /// Scan a directory that contains PostgreSQL WAL files, for the end of WAL.
+/// If precise, returns end LSN (next insertion point, basically);
+/// otherwise, start of the last segment.
+/// Returns (0, 0) if there is no WAL.
 ///
 pub fn find_end_of_wal(
     data_dir: &Path,
     wal_seg_size: usize,
     precise: bool,
-) -> (XLogRecPtr, TimeLineID) {
+    start_lsn: Lsn, // start reading WAL at this point or later
+) -> Result<(XLogRecPtr, TimeLineID)> {
     let mut high_segno: XLogSegNo = 0;
     let mut high_tli: TimeLineID = 0;
     let mut high_ispartial = false;
@@ -264,149 +285,40 @@ pub fn find_end_of_wal(
     }
     if high_segno > 0 {
         let mut high_offs = 0;
-        if precise {
-            let mut crc: u32 = 0;
-            let mut rec_offs: usize = 0;
-            let mut rec_hdr = [0u8; XLOG_SIZE_OF_XLOG_RECORD];
-            let wal_dir = data_dir.join("pg_wal");
-
-            /*
-             * To be able to calculate CRC of records crossing segment boundary,
-             * we need to parse previous segments.
-             * So first traverse segments in backward direction to locate record start
-             * and then traverse forward, accumulating CRC.
-             */
-            let mut prev_segno = high_segno - 1;
-            let mut prev_offs: u32 = 0;
-            while prev_segno > 1 {
-                // TOFO: first segment constains dummy checkpoint record at the beginning
-                prev_offs = find_end_of_wal_segment(
-                    data_dir,
-                    prev_segno,
-                    high_tli,
-                    wal_seg_size,
-                    false,
-                    &mut rec_offs,
-                    &mut rec_hdr,
-                    &mut crc,
-                    false,
-                );
-                if prev_offs != 0 {
-                    break;
-                }
-                prev_segno -= 1;
-            }
-            if prev_offs != 0 {
-                // found start of WAL record
-                let first_segno = prev_segno;
-                let first_offs = prev_offs;
-                while prev_segno + 1 < high_segno {
-                    // now traverse record in forward direction, accumulating CRC
-                    prev_segno += 1;
-                    prev_offs = find_end_of_wal_segment(
-                        data_dir,
-                        prev_segno,
-                        high_tli,
-                        wal_seg_size,
-                        false,
-                        &mut rec_offs,
-                        &mut rec_hdr,
-                        &mut crc,
-                        true,
-                    );
-                    if prev_offs == 0 {
-                        info!("Segment {} is corrupted", prev_segno,);
-                        break;
-                    }
-                }
-                if prev_offs != 0 {
-                    high_offs = find_end_of_wal_segment(
-                        data_dir,
-                        high_segno,
-                        high_tli,
-                        wal_seg_size,
-                        high_ispartial,
-                        &mut rec_offs,
-                        &mut rec_hdr,
-                        &mut crc,
-                        true,
-                    );
-                }
-                if high_offs == 0 {
-                    // If last segment contais no valid records, then return back
-                    info!("Last WAL segment {} contains no valid record, truncate WAL till {} segment",
-						  high_segno, first_segno);
-                    // Remove last segments containing corrupted WAL record
-                    for segno in first_segno + 1..high_segno {
-                        let file_name = XLogFileName(high_tli, segno, wal_seg_size);
-                        let file_path = wal_dir.join(file_name);
-                        if let Err(e) = fs::remove_file(&file_path) {
-                            info!("Failed to remove file {:?}: {}", &file_path, e);
-                        }
-                    }
-                    let file_name = XLogFileName(high_tli, high_segno, wal_seg_size);
-                    let file_path = if high_ispartial {
-                        wal_dir.join(file_name.clone() + ".partial")
-                    } else {
-                        wal_dir.join(file_name.clone())
-                    };
-                    if let Err(e) = fs::remove_file(&file_path) {
-                        info!("Failed to remove file {:?}: {}", &file_path, e);
-                    }
-                    high_ispartial = false; // previous segment should not be partial
-                    high_segno = first_segno;
-                    high_offs = first_offs;
-                }
-            } else {
-                // failed to locate previous segment
-                assert!(prev_segno <= 1);
-                high_offs = find_end_of_wal_segment(
-                    data_dir,
+        /*
+         * Move the starting pointer to the start of the next segment, if the
+         * highest one we saw was completed.
+         */
+        if !high_ispartial {
+            high_segno += 1;
+        } else if precise {
+            /* otherwise locate last record in last partial segment */
+            if start_lsn.segment_number(wal_seg_size) > high_segno {
+                bail!(
+                    "provided start_lsn {:?} is beyond highest segno {:?} available",
+                    start_lsn,
                     high_segno,
-                    high_tli,
-                    wal_seg_size,
-                    high_ispartial,
-                    &mut rec_offs,
-                    &mut rec_hdr,
-                    &mut crc,
-                    false,
                 );
             }
-
-            // If last segment is not marked as partial, it means that next segment
-            // was not written. Let's make this segment partial once again.
-            if !high_ispartial {
-                let file_name = XLogFileName(high_tli, high_segno, wal_seg_size);
-                if let Err(e) = fs::rename(
-                    wal_dir.join(file_name.clone()),
-                    wal_dir.join(file_name.clone() + ".partial"),
-                ) {
-                    info!(
-                        "Failed to rename {} to {}.partial: {}",
-                        &file_name, &file_name, e
-                    );
-                }
-            }
-        } else {
-            /*
-             * Move the starting pointer to the start of the next segment, if the
-             * highest one we saw was completed.
-             */
-            if !high_ispartial {
-                high_segno += 1;
-            }
+            high_offs = find_end_of_wal_segment(
+                data_dir,
+                high_segno,
+                high_tli,
+                wal_seg_size,
+                start_lsn.segment_offset(wal_seg_size),
+            )?;
         }
         let high_ptr = XLogSegNoOffsetToRecPtr(high_segno, high_offs, wal_seg_size);
-        return (high_ptr, high_tli);
+        return Ok((high_ptr, high_tli));
     }
-    (0, 1) // First timeline is 1
+    Ok((0, 0))
 }
 
 pub fn main() {
     let mut data_dir = PathBuf::new();
     data_dir.push(".");
     let wal_seg_size = 16 * 1024 * 1024;
-    let (wal_end, tli) = find_end_of_wal(&data_dir, wal_seg_size, true);
+    let (wal_end, tli) = find_end_of_wal(&data_dir, wal_seg_size, true, Lsn(0)).unwrap();
     println!(
         "wal_end={:>08X}{:>08X}, tli={}",
         (wal_end >> 32) as u32,
@@ -416,24 +328,19 @@ pub fn main() {
 }
 
 impl XLogRecord {
-    pub fn from_bytes(buf: &mut Bytes) -> XLogRecord {
-        XLogRecord {
-            xl_tot_len: buf.get_u32_le(),
-            xl_xid: buf.get_u32_le(),
-            xl_prev: buf.get_u64_le(),
-            xl_info: buf.get_u8(),
-            xl_rmid: buf.get_u8(),
-            xl_crc: {
-                buf.advance(2);
-                buf.get_u32_le()
-            },
-        }
+    pub fn from_slice(buf: &[u8]) -> XLogRecord {
+        use zenith_utils::bin_ser::LeSer;
+        XLogRecord::des(buf).unwrap()
+    }
+
+    pub fn from_bytes<B: Buf>(buf: &mut B) -> XLogRecord {
+        use zenith_utils::bin_ser::LeSer;
+        XLogRecord::des_from(&mut buf.reader()).unwrap()
     }
 
     pub fn encode(&self) -> Bytes {
-        let b: [u8; XLOG_SIZE_OF_XLOG_RECORD];
-        b = unsafe { std::mem::transmute::<XLogRecord, [u8; XLOG_SIZE_OF_XLOG_RECORD]>(*self) };
-        Bytes::copy_from_slice(&b[..])
+        use zenith_utils::bin_ser::LeSer;
+        self.ser().unwrap().into()
     }
 
     // Is this record an XLOG_SWITCH record? They need some special processing,
@@ -444,34 +351,20 @@ impl XLogRecord {
 
 impl XLogPageHeaderData {
     pub fn from_bytes<B: Buf>(buf: &mut B) -> XLogPageHeaderData {
-        let hdr: XLogPageHeaderData = XLogPageHeaderData {
-            xlp_magic: buf.get_u16_le(),
-            xlp_info: buf.get_u16_le(),
-            xlp_tli: buf.get_u32_le(),
-            xlp_pageaddr: buf.get_u64_le(),
-            xlp_rem_len: buf.get_u32_le(),
-        };
-        buf.get_u32_le(); //padding
-        hdr
+        use zenith_utils::bin_ser::LeSer;
+        XLogPageHeaderData::des_from(&mut buf.reader()).unwrap()
     }
 }
 
 impl XLogLongPageHeaderData {
     pub fn from_bytes<B: Buf>(buf: &mut B) -> XLogLongPageHeaderData {
-        XLogLongPageHeaderData {
-            std: XLogPageHeaderData::from_bytes(buf),
-            xlp_sysid: buf.get_u64_le(),
-            xlp_seg_size: buf.get_u32_le(),
-            xlp_xlog_blcksz: buf.get_u32_le(),
-        }
+        use zenith_utils::bin_ser::LeSer;
+        XLogLongPageHeaderData::des_from(&mut buf.reader()).unwrap()
     }
 
     pub fn encode(&self) -> Bytes {
-        let b: [u8; XLOG_SIZE_OF_XLOG_LONG_PHD];
-        b = unsafe {
-            std::mem::transmute::<XLogLongPageHeaderData, [u8; XLOG_SIZE_OF_XLOG_LONG_PHD]>(*self)
-        };
-        Bytes::copy_from_slice(&b[..])
+        use zenith_utils::bin_ser::LeSer;
+        self.ser().unwrap().into()
     }
 }
 
@@ -479,23 +372,21 @@ pub const SIZEOF_CHECKPOINT: usize = std::mem::size_of::<CheckPoint>();
 
 impl CheckPoint {
     pub fn encode(&self) -> Bytes {
-        let b: [u8; SIZEOF_CHECKPOINT];
-        b = unsafe { std::mem::transmute::<CheckPoint, [u8; SIZEOF_CHECKPOINT]>(*self) };
-        Bytes::copy_from_slice(&b[..])
+        use zenith_utils::bin_ser::LeSer;
+        self.ser().unwrap().into()
     }
 
     pub fn decode(buf: &[u8]) -> Result<CheckPoint, anyhow::Error> {
-        let mut b = [0u8; SIZEOF_CHECKPOINT];
-        b.copy_from_slice(&buf[0..SIZEOF_CHECKPOINT]);
-        let checkpoint: CheckPoint;
-        checkpoint = unsafe { std::mem::transmute::<[u8; SIZEOF_CHECKPOINT], CheckPoint>(b) };
-        Ok(checkpoint)
+        use zenith_utils::bin_ser::LeSer;
+        Ok(CheckPoint::des(buf)?)
     }
 
-    // Update next XID based on provided new_xid and stored epoch.
-    // Next XID should be greater than new_xid.
-    // Also take in account 32-bit wrap-around.
-    pub fn update_next_xid(&mut self, xid: u32) {
+    /// Update next XID based on provided new_xid and stored epoch.
+    /// Next XID should be greater than new_xid. This handles 32-bit
+    /// XID wraparound correctly.
+    ///
+    /// Returns 'true' if the XID was updated.
+    pub fn update_next_xid(&mut self, xid: u32) -> bool {
         let xid = xid.wrapping_add(XID_CHECKPOINT_INTERVAL - 1) & !(XID_CHECKPOINT_INTERVAL - 1);
         let full_xid = self.nextXid.value;
         let new_xid = std::cmp::max(xid + 1, pg_constants::FIRST_NORMAL_TRANSACTION_ID);
@@ -506,34 +397,37 @@ impl CheckPoint {
                 // wrap-around
                 epoch += 1;
             }
-            self.nextXid = FullTransactionId {
-                value: (epoch << 32) | new_xid as u64,
-            };
+            let nextXid = (epoch << 32) | new_xid as u64;
+
+            if nextXid != self.nextXid.value {
+                self.nextXid = FullTransactionId { value: nextXid };
+                return true;
+            }
         }
+        false
     }
 }
 
 //
-// Generate new WAL segment with single XLOG_CHECKPOINT_SHUTDOWN record.
+// Generate new, empty WAL segment.
 // We need this segment to start compute node.
-// In order to minimize changes in Postgres core, we prefer to
-// provide WAL segment from which is can extract checkpoint record in standard way,
-// rather then implement some alternative mechanism.
 //
-pub fn generate_wal_segment(pg_control: &ControlFileData) -> Bytes {
+pub fn generate_wal_segment(segno: u64, system_id: u64) -> Bytes {
     let mut seg_buf = BytesMut::with_capacity(pg_constants::WAL_SEGMENT_SIZE as usize);
 
+    let pageaddr = XLogSegNoOffsetToRecPtr(segno, 0, pg_constants::WAL_SEGMENT_SIZE);
     let hdr = XLogLongPageHeaderData {
         std: {
             XLogPageHeaderData {
                 xlp_magic: XLOG_PAGE_MAGIC as u16,
                 xlp_info: pg_constants::XLP_LONG_HEADER,
                 xlp_tli: 1, // FIXME: always use Postgres timeline 1
-                xlp_pageaddr: pg_control.checkPoint - XLOG_SIZE_OF_XLOG_LONG_PHD as u64,
+                xlp_pageaddr: pageaddr,
                 xlp_rem_len: 0,
+                ..Default::default() // Put 0 in padding fields.
             }
         },
-        xlp_sysid: pg_control.system_identifier,
+        xlp_sysid: system_id,
         xlp_seg_size: pg_constants::WAL_SEGMENT_SIZE as u32,
         xlp_xlog_blcksz: XLOG_BLCKSZ as u32,
     };
@@ -541,35 +435,6 @@ pub fn generate_wal_segment(pg_control: &ControlFileData) -> Bytes {
     let hdr_bytes = hdr.encode();
     seg_buf.extend_from_slice(&hdr_bytes);
 
-    let rec_hdr = XLogRecord {
-        xl_tot_len: (XLOG_SIZE_OF_XLOG_RECORD
-            + SIZE_OF_XLOG_RECORD_DATA_HEADER_SHORT
-            + SIZEOF_CHECKPOINT) as u32,
-        xl_xid: 0, //0 is for InvalidTransactionId
-        xl_prev: 0,
-        xl_info: pg_constants::XLOG_CHECKPOINT_SHUTDOWN,
-        xl_rmid: pg_constants::RM_XLOG_ID,
-        xl_crc: 0,
-    };
-
-    let mut rec_shord_hdr_bytes = BytesMut::new();
-    rec_shord_hdr_bytes.put_u8(pg_constants::XLR_BLOCK_ID_DATA_SHORT);
-    rec_shord_hdr_bytes.put_u8(SIZEOF_CHECKPOINT as u8);
-
-    let rec_bytes = rec_hdr.encode();
-    let checkpoint_bytes = pg_control.checkPointCopy.encode();
-
-    //calculate record checksum
-    let mut crc = 0;
-    crc = crc32c_append(crc, &rec_shord_hdr_bytes[..]);
-    crc = crc32c_append(crc, &checkpoint_bytes[..]);
-    crc = crc32c_append(crc, &rec_bytes[0..XLOG_RECORD_CRC_OFFS]);
-
-    seg_buf.extend_from_slice(&rec_bytes[0..XLOG_RECORD_CRC_OFFS]);
-    seg_buf.put_u32_le(crc);
-    seg_buf.extend_from_slice(&rec_shord_hdr_bytes);
-    seg_buf.extend_from_slice(&checkpoint_bytes);
-
     //zero out the rest of the file
     seg_buf.resize(pg_constants::WAL_SEGMENT_SIZE, 0);
     seg_buf.freeze()
@@ -580,7 +445,6 @@ mod tests {
     use super::*;
     use regex::Regex;
     use std::{env, process::Command, str::FromStr};
-    use zenith_utils::lsn::Lsn;
 
     // Run find_end_of_wal against file in test_wal dir
     // Ensure that it finds last record correctly
@@ -612,10 +476,10 @@ mod tests {
         let wal_seg_size = 16 * 1024 * 1024;
 
         // 3. Check end_of_wal on non-partial WAL segment (we treat it as fully populated)
-        let (wal_end, tli) = find_end_of_wal(&wal_dir, wal_seg_size, true);
+        let (wal_end, tli) = find_end_of_wal(&wal_dir, wal_seg_size, true, Lsn(0)).unwrap();
         let wal_end = Lsn(wal_end);
         println!("wal_end={}, tli={}", wal_end, tli);
-        assert_eq!(wal_end, "0/1699D10".parse::<Lsn>().unwrap());
+        assert_eq!(wal_end, "0/2000000".parse::<Lsn>().unwrap());
 
         // 4. Get the actual end of WAL by pg_waldump
         let waldump_path = top_path.join("tmp_install/bin/pg_waldump");
@@ -629,7 +493,7 @@ mod tests {
         let waldump_output = std::str::from_utf8(&waldump_output.stderr).unwrap();
         println!("waldump_output = '{}'", &waldump_output);
         let re = Regex::new(r"invalid record length at (.+):").unwrap();
-        let caps = re.captures(&waldump_output).unwrap();
+        let caps = re.captures(waldump_output).unwrap();
         let waldump_wal_end = Lsn::from_str(caps.get(1).unwrap().as_str()).unwrap();
 
         // 5. Rename file to partial to actually find last valid lsn
@@ -638,7 +502,7 @@ mod tests {
             wal_dir.join("000000010000000000000001.partial"),
         )
         .unwrap();
-        let (wal_end, tli) = find_end_of_wal(&wal_dir, wal_seg_size, true);
+        let (wal_end, tli) = find_end_of_wal(&wal_dir, wal_seg_size, true, Lsn(0)).unwrap();
         let wal_end = Lsn(wal_end);
         println!("wal_end={}, tli={}", wal_end, tli);
         assert_eq!(wal_end, waldump_wal_end);

pre-commit.py

@@ -0,0 +1,89 @@
+#!/usr/bin/env python3
+
+from typing import List
+import subprocess
+import sys
+import enum
+import argparse
+import os
+
+
+@enum.unique
+class Color(enum.Enum):
+    RED = "\033[0;31m"
+    GREEN = "\033[0;33m"
+    CYAN = "\033[0;36m"
+
+
+NC = "\033[0m"  # No Color
+
+
+def colorify(
+    s: str,
+    color: Color,
+    no_color: bool = False,
+):
+    if no_color:
+        return s
+    return f"{color.value}{s}{NC}"
+
+
+def rustfmt(fix_inplace: bool = False, no_color: bool = False) -> str:
+    cmd = "rustfmt --edition=2018"
+    if not fix_inplace:
+        cmd += " --check"
+    if no_color:
+        cmd += " --color=never"
+    return cmd
+
+
+def get_commit_files() -> List[str]:
+    files = subprocess.check_output(
+        "git diff --cached --name-only --diff-filter=ACM".split()
+    )
+    return files.decode().splitlines()
+
+
+def check(
+    name: str, suffix: str, cmd: str, changed_files: List[str], no_color: bool = False
+):
+    print(f"Checking: {name} ", end="")
+    applicable_files = list(
+        filter(lambda fname: fname.strip().endswith(suffix), changed_files)
+    )
+    if not applicable_files:
+        print(colorify("[NOT APPLICABLE]", Color.CYAN, no_color))
+        return
+
+    cmd = f'{cmd} {" ".join(applicable_files)}'
+    res = subprocess.run(cmd.split(), capture_output=True)
+    if res.returncode != 0:
+        print(colorify("[FAILED]", Color.RED, no_color))
+        print("Please inspect the output below and run make fmt to fix automatically\n")
+        print(res.stdout.decode())
+        exit(1)
+
+    print(colorify("[OK]", Color.GREEN, no_color))
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser()
+    parser.add_argument(
+        "--fix-inplace", action="store_true", help="apply fixes inplace"
+    )
+    parser.add_argument(
+        "--no-color", action="store_true", help="disable colored output", default=not sys.stdout.isatty()
+    )
+    args = parser.parse_args()
+
+    files = get_commit_files()
+    # we use rustfmt here because cargo fmt does not accept list of files
+    # it internally gathers project files and feeds them to rustfmt
+    # so because we want to check only files included in the commit we use rustfmt directly
+    check(
+        name="rustfmt",
+        suffix=".rs",
+        cmd=rustfmt(fix_inplace=args.fix_inplace, no_color=args.no_color),
+        changed_files=files,
+        no_color=args.no_color,
+    )

proxy/Cargo.toml

@@ -14,8 +14,10 @@ rand = "0.8.3"
 hex = "0.4.3"
 serde = "1"
 serde_json = "1"
-tokio = { version = "1.7.1", features = ["full"] }
-tokio-postgres = "0.7.2"
+tokio = "1.11"
+tokio-postgres = { git = "https://github.com/zenithdb/rust-postgres.git", rev="9eb0dbfbeb6a6c1b79099b9f7ae4a8c021877858" }
 clap = "2.33.0"
+rustls = "0.19.1"
+reqwest = { version = "0.11", features = ["blocking", "json"] }
 
 zenith_utils = { path = "../zenith_utils" }

proxy/src/cplane_api.rs

@@ -1,92 +1,88 @@
-use anyhow::{bail, Result};
+use anyhow::{bail, Context, Result};
 use serde::{Deserialize, Serialize};
-use std::{
-    collections::HashMap,
-    net::{IpAddr, SocketAddr},
-};
+use std::net::{SocketAddr, ToSocketAddrs};
 
 pub struct CPlaneApi {
-    // address: SocketAddr,
+    auth_endpoint: &'static str,
 }
 
-#[derive(Serialize, Deserialize)]
+#[derive(Serialize, Deserialize, Debug)]
 pub struct DatabaseInfo {
-    pub host: IpAddr, // TODO: allow host name here too
+    pub host: String,
     pub port: u16,
     pub dbname: String,
     pub user: String,
-    pub password: String,
+    pub password: Option<String>,
+}
+
+#[derive(Serialize, Deserialize, Debug)]
+pub struct ProxyAuthResult {
+    pub ready: bool,
+    pub error: Option<String>,
+    pub conn_info: Option<DatabaseInfo>,
 }
 
 impl DatabaseInfo {
-    pub fn socket_addr(&self) -> SocketAddr {
-        SocketAddr::new(self.host, self.port)
-    }
-
-    pub fn conn_string(&self) -> String {
-        format!(
-            "dbname={} user={} password={}",
-            self.dbname, self.user, self.password
-        )
+    pub fn socket_addr(&self) -> Result<SocketAddr> {
+        let host_port = format!("{}:{}", self.host, self.port);
+        host_port
+            .to_socket_addrs()
+            .with_context(|| format!("cannot resolve {} to SocketAddr", host_port))?
+            .next()
+            .ok_or_else(|| anyhow::Error::msg("cannot resolve at least one SocketAddr"))
     }
 }
 
-// mock cplane api
-impl CPlaneApi {
-    pub fn new(_address: &SocketAddr) -> CPlaneApi {
-        CPlaneApi {
-            // address: address.clone(),
+impl From<DatabaseInfo> for tokio_postgres::Config {
+    fn from(db_info: DatabaseInfo) -> Self {
+        let mut config = tokio_postgres::Config::new();
+
+        config
+            .host(&db_info.host)
+            .port(db_info.port)
+            .dbname(&db_info.dbname)
+            .user(&db_info.user);
+
+        if let Some(password) = db_info.password {
+            config.password(password);
         }
+
+        config
+    }
+}
+
+impl CPlaneApi {
+    pub fn new(auth_endpoint: &'static str) -> CPlaneApi {
+        CPlaneApi { auth_endpoint }
     }
 
-    pub fn check_auth(&self, user: &str, md5_response: &[u8], salt: &[u8; 4]) -> Result<()> {
-        // passwords for both is "mypass"
-        let auth_map: HashMap<_, &str> = vec![
-            ("stas@zenith", "716ee6e1c4a9364d66285452c47402b1"),
-            ("stas2@zenith", "3996f75df64c16a8bfaf01301b61d582"),
-        ]
-        .into_iter()
-        .collect();
+    pub fn authenticate_proxy_request(
+        &self,
+        user: &str,
+        database: &str,
+        md5_response: &[u8],
+        salt: &[u8; 4],
+        psql_session_id: &str,
+    ) -> Result<ProxyAuthResult> {
+        let mut url = reqwest::Url::parse(self.auth_endpoint)?;
+        url.query_pairs_mut()
+            .append_pair("login", user)
+            .append_pair("database", database)
+            .append_pair("md5response", std::str::from_utf8(md5_response)?)
+            .append_pair("salt", &hex::encode(salt))
+            .append_pair("psql_session_id", psql_session_id);
 
-        let stored_hash = auth_map
-            .get(&user)
-            .ok_or_else(|| anyhow::Error::msg("user not found"))?;
-        let salted_stored_hash = format!(
-            "md5{:x}",
-            md5::compute([stored_hash.as_bytes(), salt].concat())
-        );
+        println!("cplane request: {}", url.as_str());
 
-        let received_hash = std::str::from_utf8(&md5_response)?;
+        let resp = reqwest::blocking::get(url)?;
 
-        println!(
-            "auth: {} rh={} sh={} ssh={} {:?}",
-            user, received_hash, stored_hash, salted_stored_hash, salt
-        );
+        if resp.status().is_success() {
+            let auth_info: ProxyAuthResult = serde_json::from_str(resp.text()?.as_str())?;
+            println!("got auth info: #{:?}", auth_info);
 
-        if received_hash == salted_stored_hash {
-            Ok(())
+            Ok(auth_info)
         } else {
             bail!("Auth failed")
         }
     }
-
-    pub fn get_database_uri(&self, _user: &str, _database: &str) -> Result<DatabaseInfo> {
-        Ok(DatabaseInfo {
-            host: "127.0.0.1".parse()?,
-            port: 5432,
-            dbname: "stas".to_string(),
-            user: "stas".to_string(),
-            password: "mypass".to_string(),
-        })
-    }
-
-    // pub fn create_database(&self, _user: &String, _database: &String) -> Result<DatabaseInfo> {
-    //     Ok(DatabaseInfo {
-    //         host: "127.0.0.1".parse()?,
-    //         port: 5432,
-    //         dbname: "stas".to_string(),
-    //         user: "stas".to_string(),
-    //         password: "mypass".to_string(),
-    //     })
-    // }
 }

proxy/src/main.rs

@@ -7,14 +7,17 @@
 ///
 use std::{
     collections::HashMap,
-    net::{SocketAddr, TcpListener},
-    sync::{mpsc, Mutex},
+    net::SocketAddr,
+    sync::{mpsc, Arc, Mutex},
     thread,
 };
 
-use clap::{App, Arg};
+use anyhow::{anyhow, bail, ensure, Context};
+use clap::{App, Arg, ArgMatches};
 
 use cplane_api::DatabaseInfo;
+use rustls::{internal::pemfile, NoClientAuth, ProtocolVersion, ServerConfig};
+use zenith_utils::{tcp_listener, GIT_VERSION};
 
 mod cplane_api;
 mod mgmt;
@@ -32,7 +35,9 @@ pub struct ProxyConf {
     pub redirect_uri: String,
 
     /// control plane address where we would check auth.
-    pub cplane_address: SocketAddr,
+    pub auth_endpoint: String,
+
+    pub ssl_config: Option<Arc<ServerConfig>>,
 }
 
 pub struct ProxyState {
@@ -40,8 +45,40 @@ pub struct ProxyState {
     pub waiters: Mutex<HashMap<String, mpsc::Sender<anyhow::Result<DatabaseInfo>>>>,
 }
 
+fn configure_ssl(arg_matches: &ArgMatches) -> anyhow::Result<Option<Arc<ServerConfig>>> {
+    let (key_path, cert_path) = match (
+        arg_matches.value_of("ssl-key"),
+        arg_matches.value_of("ssl-cert"),
+    ) {
+        (Some(key_path), Some(cert_path)) => (key_path, cert_path),
+        (None, None) => return Ok(None),
+        _ => bail!("either both or neither ssl-key and ssl-cert must be specified"),
+    };
+
+    let key = {
+        let key_bytes = std::fs::read(key_path).context("SSL key file")?;
+        let mut keys = pemfile::pkcs8_private_keys(&mut &key_bytes[..])
+            .map_err(|_| anyhow!("couldn't read TLS keys"))?;
+        ensure!(keys.len() == 1, "keys.len() = {} (should be 1)", keys.len());
+        keys.pop().unwrap()
+    };
+
+    let cert_chain = {
+        let cert_chain_bytes = std::fs::read(cert_path).context("SSL cert file")?;
+        pemfile::certs(&mut &cert_chain_bytes[..])
+            .map_err(|_| anyhow!("couldn't read TLS certificates"))?
+    };
+
+    let mut config = ServerConfig::new(NoClientAuth::new());
+    config.set_single_cert(cert_chain, key)?;
+    config.versions = vec![ProtocolVersion::TLSv1_3];
+
+    Ok(Some(Arc::new(config)))
+}
+
 fn main() -> anyhow::Result<()> {
     let arg_matches = App::new("Zenith proxy/router")
+        .version(GIT_VERSION)
         .arg(
             Arg::with_name("proxy")
                 .short("p")
@@ -66,13 +103,36 @@ fn main() -> anyhow::Result<()> {
                 .help("redirect unauthenticated users to given uri")
                 .default_value("http://localhost:3000/psql_session/"),
         )
+        .arg(
+            Arg::with_name("auth-endpoint")
+                .short("a")
+                .long("auth-endpoint")
+                .takes_value(true)
+                .help("redirect unauthenticated users to given uri")
+                .default_value("http://localhost:3000/authenticate_proxy_request/"),
+        )
+        .arg(
+            Arg::with_name("ssl-key")
+                .short("k")
+                .long("ssl-key")
+                .takes_value(true)
+                .help("path to SSL key for client postgres connections"),
+        )
+        .arg(
+            Arg::with_name("ssl-cert")
+                .short("c")
+                .long("ssl-cert")
+                .takes_value(true)
+                .help("path to SSL cert for client postgres connections"),
+        )
         .get_matches();
 
     let conf = ProxyConf {
         proxy_address: arg_matches.value_of("proxy").unwrap().parse()?,
         mgmt_address: arg_matches.value_of("mgmt").unwrap().parse()?,
         redirect_uri: arg_matches.value_of("uri").unwrap().parse()?,
-        cplane_address: "127.0.0.1:3000".parse()?,
+        auth_endpoint: arg_matches.value_of("auth-endpoint").unwrap().parse()?,
+        ssl_config: configure_ssl(&arg_matches)?,
     };
     let state = ProxyState {
         conf,
@@ -80,25 +140,27 @@ fn main() -> anyhow::Result<()> {
     };
     let state: &'static ProxyState = Box::leak(Box::new(state));
 
+    println!("Version: {}", GIT_VERSION);
+
     // Check that we can bind to address before further initialization
     println!("Starting proxy on {}", state.conf.proxy_address);
-    let pageserver_listener = TcpListener::bind(state.conf.proxy_address)?;
+    let pageserver_listener = tcp_listener::bind(state.conf.proxy_address)?;
 
     println!("Starting mgmt on {}", state.conf.mgmt_address);
-    let mgmt_listener = TcpListener::bind(state.conf.mgmt_address)?;
+    let mgmt_listener = tcp_listener::bind(state.conf.mgmt_address)?;
 
-    let threads = vec![
+    let threads = [
         // Spawn a thread to listen for connections. It will spawn further threads
         // for each connection.
         thread::Builder::new()
-            .name("Proxy thread".into())
-            .spawn(move || proxy::thread_main(&state, pageserver_listener))?,
+            .name("Listener thread".into())
+            .spawn(move || proxy::thread_main(state, pageserver_listener))?,
         thread::Builder::new()
             .name("Mgmt thread".into())
-            .spawn(move || mgmt::thread_main(&state, mgmt_listener))?,
+            .spawn(move || mgmt::thread_main(state, mgmt_listener))?,
     ];
 
-    for t in threads.into_iter() {
+    for t in threads {
         t.join().unwrap()?;
     }
 

proxy/src/mgmt.rs

@@ -5,7 +5,7 @@ use std::{
 
 use anyhow::bail;
 use bytes::Bytes;
-use serde::{Deserialize, Serialize};
+use serde::Deserialize;
 use zenith_utils::{
     postgres_backend::{self, query_from_cstring, AuthType, PostgresBackend},
     pq_proto::{BeMessage, SINGLE_COL_ROWDESC},
@@ -34,7 +34,7 @@ pub fn thread_main(state: &'static ProxyState, listener: TcpListener) -> anyhow:
 
 pub fn mgmt_conn_main(state: &'static ProxyState, socket: TcpStream) -> anyhow::Result<()> {
     let mut conn_handler = MgmtHandler { state };
-    let pgbackend = PostgresBackend::new(socket, AuthType::Trust)?;
+    let pgbackend = PostgresBackend::new(socket, AuthType::Trust, None, true)?;
     pgbackend.run(&mut conn_handler)
 }
 
@@ -49,7 +49,7 @@ struct MgmtHandler {
 //             "host": "127.0.0.1",
 //             "port": 5432,
 //             "dbname": "stas",
-//             "user": "stas"
+//             "user": "stas",
 //             "password": "mypass"
 //         }
 //     }
@@ -60,13 +60,16 @@ struct MgmtHandler {
 //         "Failure": "oops"
 //     }
 // }
-#[derive(Serialize, Deserialize)]
+//
+// // to test manually by sending a query to mgmt interface:
+// psql -h 127.0.0.1 -p 9999 -c '{"session_id":"4f10dde522e14739","result":{"Success":{"host":"127.0.0.1","port":5432,"dbname":"stas","user":"stas","password":"stas"}}}'
+#[derive(Deserialize)]
 pub struct PsqlSessionResponse {
     session_id: String,
     result: PsqlSessionResult,
 }
 
-#[derive(Serialize, Deserialize)]
+#[derive(Deserialize)]
 pub enum PsqlSessionResult {
     Success(DatabaseInfo),
     Failure(String),
@@ -78,34 +81,47 @@ impl postgres_backend::Handler for MgmtHandler {
         pgb: &mut PostgresBackend,
         query_string: Bytes,
     ) -> anyhow::Result<()> {
-        let query_string = query_from_cstring(query_string);
+        let res = try_process_query(self, pgb, query_string);
+        // intercept and log error message
+        if res.is_err() {
+            println!("Mgmt query failed: #{:?}", res);
+        }
+        res
+    }
+}
 
-        println!("Got mgmt query: '{}'", std::str::from_utf8(&query_string)?);
+fn try_process_query(
+    mgmt: &mut MgmtHandler,
+    pgb: &mut PostgresBackend,
+    query_string: Bytes,
+) -> anyhow::Result<()> {
+    let query_string = query_from_cstring(query_string);
 
-        let resp: PsqlSessionResponse = serde_json::from_slice(&query_string)?;
+    println!("Got mgmt query: '{}'", std::str::from_utf8(&query_string)?);
 
-        let waiters = self.state.waiters.lock().unwrap();
+    let resp: PsqlSessionResponse = serde_json::from_slice(&query_string)?;
 
-        let sender = waiters
-            .get(&resp.session_id)
-            .ok_or_else(|| anyhow::Error::msg("psql_session_id is not found"))?;
+    let waiters = mgmt.state.waiters.lock().unwrap();
 
-        match resp.result {
-            PsqlSessionResult::Success(db_info) => {
-                sender.send(Ok(db_info))?;
+    let sender = waiters
+        .get(&resp.session_id)
+        .ok_or_else(|| anyhow::Error::msg("psql_session_id is not found"))?;
 
-                pgb.write_message_noflush(&SINGLE_COL_ROWDESC)?
-                    .write_message_noflush(&BeMessage::DataRow(&[Some(b"ok")]))?
-                    .write_message_noflush(&BeMessage::CommandComplete(b"SELECT 1"))?;
-                pgb.flush()?;
-                Ok(())
-            }
+    match resp.result {
+        PsqlSessionResult::Success(db_info) => {
+            sender.send(Ok(db_info))?;
 
-            PsqlSessionResult::Failure(message) => {
-                sender.send(Err(anyhow::Error::msg(message.clone())))?;
+            pgb.write_message_noflush(&SINGLE_COL_ROWDESC)?
+                .write_message_noflush(&BeMessage::DataRow(&[Some(b"ok")]))?
+                .write_message_noflush(&BeMessage::CommandComplete(b"SELECT 1"))?;
+            pgb.flush()?;
+            Ok(())
+        }
 
-                bail!("psql session request failed: {}", message)
-            }
+        PsqlSessionResult::Failure(message) => {
+            sender.send(Err(anyhow::Error::msg(message.clone())))?;
+
+            bail!("psql session request failed: {}", message)
         }
     }
 }

proxy/src/proxy.rs

@@ -6,11 +6,11 @@ use anyhow::bail;
 use tokio_postgres::NoTls;
 
 use rand::Rng;
-use std::sync::mpsc::channel;
-use std::thread;
-use tokio::io::AsyncWriteExt;
+use std::{io, sync::mpsc::channel, thread};
+use zenith_utils::postgres_backend::Stream;
 use zenith_utils::postgres_backend::{PostgresBackend, ProtoState};
 use zenith_utils::pq_proto::*;
+use zenith_utils::sock_split::{ReadStream, WriteStream};
 use zenith_utils::{postgres_backend, pq_proto::BeMessage};
 
 ///
@@ -27,11 +27,13 @@ pub fn thread_main(
         println!("accepted connection from {}", peer_addr);
         socket.set_nodelay(true).unwrap();
 
-        thread::spawn(move || {
-            if let Err(err) = proxy_conn_main(state, socket) {
-                println!("error: {}", err);
-            }
-        });
+        thread::Builder::new()
+            .name("Proxy thread".into())
+            .spawn(move || {
+                if let Err(err) = proxy_conn_main(state, socket) {
+                    println!("error: {}", err);
+                }
+            })?;
     }
 }
 
@@ -56,10 +58,15 @@ pub fn proxy_conn_main(
 ) -> anyhow::Result<()> {
     let mut conn = ProxyConnection {
         state,
-        cplane: CPlaneApi::new(&state.conf.cplane_address),
+        cplane: CPlaneApi::new(&state.conf.auth_endpoint),
         user: "".into(),
         database: "".into(),
-        pgb: PostgresBackend::new(socket, postgres_backend::AuthType::MD5)?,
+        pgb: PostgresBackend::new(
+            socket,
+            postgres_backend::AuthType::MD5,
+            state.conf.ssl_config.clone(),
+            false,
+        )?,
         md5_salt: [0u8; 4],
         psql_session_id: "".into(),
     };
@@ -68,24 +75,20 @@ pub fn proxy_conn_main(
     // This will set conn.existing_user and we can decide on next actions
     conn.handle_startup()?;
 
+    let mut psql_session_id_buf = [0u8; 8];
+    rand::thread_rng().fill(&mut psql_session_id_buf);
+    conn.psql_session_id = hex::encode(psql_session_id_buf);
+
     // both scenarious here should end up producing database connection string
-    let db_info = if conn.is_existing_user() {
+    let conn_info = if conn.is_existing_user() {
         conn.handle_existing_user()?
     } else {
         conn.handle_new_user()?
     };
 
-    // ok, proxy pass user connection to database_uri
-    let runtime = tokio::runtime::Builder::new_current_thread()
-        .enable_all()
-        .build()
-        .unwrap();
-
-    let _ = runtime.block_on(proxy_pass(conn.pgb, db_info))?;
-
-    println!("proxy_conn_main done;");
-
-    Ok(())
+    // XXX: move that inside handle_new_user/handle_existing_user to be able to
+    // report wrong connection error.
+    proxy_pass(conn.pgb, conn_info)
 }
 
 impl ProxyConnection {
@@ -94,6 +97,7 @@ impl ProxyConnection {
     }
 
     fn handle_startup(&mut self) -> anyhow::Result<()> {
+        let mut encrypted = false;
         loop {
             let msg = self.pgb.read_message()?;
             println!("got message {:?}", msg);
@@ -102,11 +106,29 @@ impl ProxyConnection {
                     println!("got startup message {:?}", m);
 
                     match m.kind {
-                        StartupRequestCode::NegotiateGss | StartupRequestCode::NegotiateSsl => {
+                        StartupRequestCode::NegotiateGss => {
+                            self.pgb
+                                .write_message(&BeMessage::EncryptionResponse(false))?;
+                        }
+                        StartupRequestCode::NegotiateSsl => {
                             println!("SSL requested");
-                            self.pgb.write_message(&BeMessage::Negotiate)?;
+                            if self.pgb.tls_config.is_some() {
+                                self.pgb
+                                    .write_message(&BeMessage::EncryptionResponse(true))?;
+                                self.pgb.start_tls()?;
+                                encrypted = true;
+                            } else {
+                                self.pgb
+                                    .write_message(&BeMessage::EncryptionResponse(false))?;
+                            }
                         }
                         StartupRequestCode::Normal => {
+                            if self.state.conf.ssl_config.is_some() && !encrypted {
+                                self.pgb.write_message(&BeMessage::ErrorResponse(
+                                    "must connect with TLS".to_string(),
+                                ))?;
+                                bail!("client did not connect with TLS");
+                            }
                             self.user = m
                                 .params
                                 .get("user")
@@ -138,9 +160,25 @@ impl ProxyConnection {
         Ok(())
     }
 
+    // Wait for proxy kick form the console with conninfo
+    fn wait_for_conninfo(&mut self) -> anyhow::Result<DatabaseInfo> {
+        let (tx, rx) = channel::<anyhow::Result<DatabaseInfo>>();
+        let _ = self
+            .state
+            .waiters
+            .lock()
+            .unwrap()
+            .insert(self.psql_session_id.clone(), tx);
+
+        // Wait for web console response
+        // TODO: respond with error to client
+        rx.recv()?
+    }
+
     fn handle_existing_user(&mut self) -> anyhow::Result<DatabaseInfo> {
         // ask password
         rand::thread_rng().fill(&mut self.md5_salt);
+
         self.pgb
             .write_message(&BeMessage::AuthenticationMD5Password(&self.md5_salt))?;
         self.pgb.state = ProtoState::Authentication; // XXX
@@ -158,38 +196,71 @@ impl ProxyConnection {
                 .split_last()
                 .ok_or_else(|| anyhow::Error::msg("unexpected password message"))?;
 
-            if let Err(e) = self.check_auth_md5(md5_response) {
-                self.pgb
-                    .write_message(&BeMessage::ErrorResponse(format!("{}", e)))?;
-                bail!("auth failed: {}", e);
-            } else {
-                self.pgb
-                    .write_message_noflush(&BeMessage::AuthenticationOk)?;
-                self.pgb
-                    .write_message_noflush(&BeMessage::ParameterStatus)?;
-                self.pgb.write_message(&BeMessage::ReadyForQuery)?;
-            }
-        }
+            match self.cplane.authenticate_proxy_request(
+                self.user.as_str(),
+                self.database.as_str(),
+                md5_response,
+                &self.md5_salt,
+                &self.psql_session_id,
+            ) {
+                Err(e) => {
+                    self.pgb.write_message(&BeMessage::ErrorResponse(format!(
+                        "cannot authenticate proxy: {}",
+                        e
+                    )))?;
 
-        // ok, we are authorized
-        self.cplane.get_database_uri(&self.user, &self.database)
+                    bail!("auth failed: {}", e);
+                }
+
+                Ok(auth_info) => {
+                    let conn_info = if auth_info.ready {
+                        // Cluster is ready, so just take `conn_info` and respond to the client.
+                        auth_info
+                            .conn_info
+                            .expect("conn_info should be provided with ready cluster")
+                    } else {
+                        match auth_info.error {
+                            Some(e) => {
+                                self.pgb.write_message(&BeMessage::ErrorResponse(format!(
+                                    "cannot authenticate proxy: {}",
+                                    e
+                                )))?;
+
+                                bail!("auth failed: {}", e);
+                            }
+                            None => {
+                                // Cluster exists, but isn't active, await its start and proxy kick
+                                // with `conn_info`.
+                                self.wait_for_conninfo()?
+                            }
+                        }
+                    };
+
+                    self.pgb
+                        .write_message_noflush(&BeMessage::AuthenticationOk)?;
+                    self.pgb
+                        .write_message_noflush(&BeMessage::ParameterStatus)?;
+                    self.pgb.write_message(&BeMessage::ReadyForQuery)?;
+
+                    Ok(conn_info)
+                }
+            }
+        } else {
+            bail!("protocol violation");
+        }
     }
 
     fn handle_new_user(&mut self) -> anyhow::Result<DatabaseInfo> {
-        let mut psql_session_id_buf = [0u8; 8];
-        rand::thread_rng().fill(&mut psql_session_id_buf);
-        self.psql_session_id = hex::encode(psql_session_id_buf);
-
         let hello_message = format!("☀️  Welcome to Zenith!
 
-To proceed with database creation open following link:
+To proceed with database creation, open the following link:
 
-    {}{}
+    {redirect_uri}{sess_id}
 
-It needed to be done once and we will send you '.pgpass' file which will allow you to access or create
+It needs to be done once and we will send you '.pgpass' file, which will allow you to access or create
 databases without opening the browser.
 
-", self.state.conf.redirect_uri,self.psql_session_id);
+", redirect_uri = self.state.conf.redirect_uri, sess_id = self.psql_session_id);
 
         self.pgb
             .write_message_noflush(&BeMessage::AuthenticationOk)?;
@@ -198,59 +269,83 @@ databases without opening the browser.
         self.pgb
             .write_message(&BeMessage::NoticeResponse(hello_message))?;
 
-        // await for database creation
-        let (tx, rx) = channel::<anyhow::Result<DatabaseInfo>>();
-        let _ = self
-            .state
-            .waiters
-            .lock()
-            .unwrap()
-            .insert(self.psql_session_id.clone(), tx);
-
-        // Wait for web console response
-        // XXX: respond with error to client
-        let dbinfo = rx.recv()??;
+        // We requested the DB creation from the console. Now wait for conninfo
+        let conn_info = self.wait_for_conninfo()?;
 
         self.pgb.write_message_noflush(&BeMessage::NoticeResponse(
             "Connecting to database.".to_string(),
         ))?;
         self.pgb.write_message(&BeMessage::ReadyForQuery)?;
 
-        Ok(dbinfo)
-    }
-
-    fn check_auth_md5(&self, md5_response: &[u8]) -> anyhow::Result<()> {
-        assert!(self.is_existing_user());
-        self.cplane
-            .check_auth(self.user.as_str(), md5_response, &self.md5_salt)
+        Ok(conn_info)
     }
 }
 
-async fn proxy_pass(pgb: PostgresBackend, db_info: DatabaseInfo) -> anyhow::Result<()> {
-    let mut socket = tokio::net::TcpStream::connect(db_info.socket_addr()).await?;
-    let config = db_info.conn_string().parse::<tokio_postgres::Config>()?;
+/// Create a TCP connection to a postgres database, authenticate with it, and receive the ReadyForQuery message
+async fn connect_to_db(db_info: DatabaseInfo) -> anyhow::Result<tokio::net::TcpStream> {
+    let mut socket = tokio::net::TcpStream::connect(db_info.socket_addr()?).await?;
+    let config = tokio_postgres::Config::from(db_info);
     let _ = config.connect_raw(&mut socket, NoTls).await?;
+    Ok(socket)
+}
 
-    println!("Connected to pg, proxying");
+/// Concurrently proxy both directions of the client and server connections
+fn proxy(
+    (client_read, client_write): (ReadStream, WriteStream),
+    (server_read, server_write): (ReadStream, WriteStream),
+) -> anyhow::Result<()> {
+    fn do_proxy(mut reader: impl io::Read, mut writer: WriteStream) -> io::Result<u64> {
+        /// FlushWriter will make sure that every message is sent as soon as possible
+        struct FlushWriter<W>(W);
 
-    let incoming_std = pgb.into_stream();
-    incoming_std.set_nonblocking(true)?;
-    let mut incoming_conn = tokio::net::TcpStream::from_std(incoming_std)?;
+        impl<W: io::Write> io::Write for FlushWriter<W> {
+            fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+                // `std::io::copy` is guaranteed to exit if we return an error,
+                // so we can afford to lose `res` in case `flush` fails
+                let res = self.0.write(buf);
+                if res.is_ok() {
+                    self.0.flush()?;
+                }
+                res
+            }
 
-    let (mut ri, mut wi) = incoming_conn.split();
-    let (mut ro, mut wo) = socket.split();
+            fn flush(&mut self) -> io::Result<()> {
+                self.0.flush()
+            }
+        }
 
-    let client_to_server = async {
-        tokio::io::copy(&mut ri, &mut wo).await?;
-        wo.shutdown().await
-    };
+        let res = std::io::copy(&mut reader, &mut FlushWriter(&mut writer));
+        writer.shutdown(std::net::Shutdown::Both)?;
+        res
+    }
 
-    let server_to_client = async {
-        tokio::io::copy(&mut ro, &mut wi).await?;
-        wi.shutdown().await
-    };
+    let client_to_server_jh = thread::spawn(move || do_proxy(client_read, server_write));
 
-    tokio::try_join!(client_to_server, server_to_client)?;
+    do_proxy(server_read, client_write)?;
+    client_to_server_jh.join().unwrap()?;
 
     Ok(())
 }
+
+/// Proxy a client connection to a postgres database
+fn proxy_pass(pgb: PostgresBackend, db_info: DatabaseInfo) -> anyhow::Result<()> {
+    let db_stream = {
+        // We'll get rid of this once migration to async is complete
+        let runtime = tokio::runtime::Builder::new_current_thread()
+            .enable_all()
+            .build()?;
+
+        let stream = runtime.block_on(connect_to_db(db_info))?.into_std()?;
+        stream.set_nonblocking(false)?;
+        stream
+    };
+
+    let db = zenith_utils::sock_split::BidiStream::from_tcp(db_stream);
+
+    let client = match pgb.into_stream() {
+        Stream::Bidirectional(bidi_stream) => bidi_stream,
+        _ => bail!("invalid stream"),
+    };
+
+    proxy(client.split(), db.split())
+}

run_clippy.sh

@@ -8,4 +8,8 @@
 # warnings and errors right in the editor.
 # In vscode, this setting is Rust-analyzer>Check On Save:Command
 
-cargo clippy "${@:2}" -- -A clippy::new_without_default -A clippy::manual_range_contains -A clippy::comparison_chain
+
+# * `-A unknown_lints` – do not warn about unknown lint suppressions
+#                        that people with newer toolchains might use
+# * `-D warnings`      - fail on any warnings (`cargo` returns non-zero exit status)
+cargo clippy "${@:2}" --all-targets --all-features --all --tests -- -A unknown_lints -D warnings

scripts/generate_perf_report_page.py

@@ -0,0 +1,218 @@
+#!/usr/bin/env python3
+import argparse
+from dataclasses import dataclass
+from pathlib import Path
+import json
+from typing import Any, Dict, List, Optional, Tuple, cast
+from jinja2 import Template
+
+# skip 'input' columns. They are included in the header and just blow the table
+EXCLUDE_COLUMNS = frozenset({
+    'scale',
+    'duration',
+    'number_of_clients',
+    'number_of_threads',
+    'init_start_timestamp',
+    'init_end_timestamp',
+    'run_start_timestamp',
+    'run_end_timestamp',
+})
+
+KEY_EXCLUDE_FIELDS = frozenset({
+    'init_start_timestamp',
+    'init_end_timestamp',
+    'run_start_timestamp',
+    'run_end_timestamp',
+})
+NEGATIVE_COLOR = 'negative'
+POSITIVE_COLOR = 'positive'
+
+
+@dataclass
+class SuitRun:
+    revision: str
+    values: Dict[str, Any]
+
+
+@dataclass
+class SuitRuns:
+    platform: str
+    suit: str
+    common_columns: List[str]
+    value_columns: List[str]
+    runs: List[SuitRun]
+
+
+@dataclass
+class RowValue:
+    value: str
+    color: str
+    ratio: str
+
+
+def get_columns(values: List[Dict]) -> Tuple[List[Tuple[str, str]], List[str]]:
+    value_columns = []
+    common_columns = []
+    for item in values:
+        if item['name'] in KEY_EXCLUDE_FIELDS:
+            continue
+        if item['report'] != 'test_param':
+            value_columns.append(cast(str, item['name']))
+        else:
+            common_columns.append(
+                (cast(str, item['name']), cast(str, item['value'])))
+    value_columns.sort()
+    common_columns.sort(key=lambda x: x[0])  # sort by name
+    return common_columns, value_columns
+
+
+def format_ratio(ratio: float, report: str) -> Tuple[str, str]:
+    color = ''
+    sign = '+' if ratio > 0 else ''
+    if abs(ratio) < 0.05:
+        return f'&nbsp({sign}{ratio:.2f})', color
+
+    if report not in {'test_param', 'higher_is_better', 'lower_is_better'}:
+        raise ValueError(f'Unknown report type: {report}')
+
+    if report == 'test_param':
+        return f'{ratio:.2f}', color
+
+    if ratio > 0:
+        if report == 'higher_is_better':
+            color = POSITIVE_COLOR
+        elif report == 'lower_is_better':
+            color = NEGATIVE_COLOR
+    elif ratio < 0:
+        if report == 'higher_is_better':
+            color = NEGATIVE_COLOR
+        elif report == 'lower_is_better':
+            color = POSITIVE_COLOR
+
+    return f'&nbsp({sign}{ratio:.2f})', color
+
+
+def extract_value(name: str, suit_run: SuitRun) -> Optional[Dict[str, Any]]:
+    for item in suit_run.values['data']:
+        if item['name'] == name:
+            return item
+    return None
+
+
+def get_row_values(columns: List[str], run_result: SuitRun,
+                   prev_result: Optional[SuitRun]) -> List[RowValue]:
+    row_values = []
+    for column in columns:
+        current_value = extract_value(column, run_result)
+        if current_value is None:
+            # should never happen
+            raise ValueError(f'{column} not found in {run_result.values}')
+
+        value = current_value["value"]
+        if isinstance(value, float):
+            value = f'{value:.2f}'
+
+        if prev_result is None:
+            row_values.append(RowValue(value, '', ''))
+            continue
+
+        prev_value = extract_value(column, prev_result)
+        if prev_value is None:
+            # this might happen when new metric is added and there is no value for it in previous run
+            # let this be here, TODO add proper handling when this actually happens
+            raise ValueError(f'{column} not found in previous result')
+        ratio = float(value) / float(prev_value['value']) - 1
+        ratio_display, color = format_ratio(ratio,
+                                            current_value['report'])
+        row_values.append(RowValue(value, color, ratio_display))
+    return row_values
+
+
+@dataclass
+class SuiteRunTableRow:
+    revision: str
+    values: List[RowValue]
+
+
+def prepare_rows_from_runs(value_columns: List[str],
+                           runs: List[SuitRun]) -> List[SuiteRunTableRow]:
+    rows = []
+    prev_run = None
+    for run in runs:
+        rows.append(
+            SuiteRunTableRow(revision=run.revision,
+                             values=get_row_values(value_columns, run,
+                                                   prev_run)))
+        prev_run = run
+
+    return rows
+
+
+def main(args: argparse.Namespace) -> None:
+    input_dir = Path(args.input_dir)
+    grouped_runs = {}
+    # we have files in form: <ctr>_<rev>.json
+    # fill them in the hashmap so we have grouped items for the
+    # same run configuration (scale, duration etc.) ordered by counter.
+    for item in sorted(input_dir.iterdir(),
+                       key=lambda x: int(x.name.split('_')[0])):
+        run_data = json.loads(item.read_text())
+        revision = run_data['revision']
+
+        for suit_result in run_data['result']:
+            key = "{}{}".format(run_data['platform'], suit_result['suit'])
+            # pack total duration as a synthetic value
+            total_duration = suit_result['total_duration']
+            suit_result['data'].append({
+                'name': 'total_duration',
+                'value': total_duration,
+                'unit': 's',
+                'report': 'lower_is_better',
+            })
+            common_columns, value_columns = get_columns(suit_result['data'])
+
+            grouped_runs.setdefault(
+                key,
+                SuitRuns(
+                    platform=run_data['platform'],
+                    suit=suit_result['suit'],
+                    common_columns=common_columns,
+                    value_columns=value_columns,
+                    runs=[],
+                ),
+            )
+
+            grouped_runs[key].runs.append(
+                SuitRun(revision=revision, values=suit_result))
+    context = {}
+    for result in grouped_runs.values():
+        suit = result.suit
+        context[suit] = {
+            'common_columns':
+            result.common_columns,
+            'value_columns':
+            result.value_columns,
+            'platform':
+            result.platform,
+            # reverse the order so newest results are on top of the table
+            'rows':
+            reversed(prepare_rows_from_runs(result.value_columns,
+                                            result.runs)),
+        }
+
+    template = Template((Path(__file__).parent / 'perf_report_template.html').read_text())
+
+    Path(args.out).write_text(template.render(context=context))
+
+
+if __name__ == '__main__':
+    parser = argparse.ArgumentParser()
+    parser.add_argument(
+        '--input-dir',
+        dest='input_dir',
+        required=True,
+        help='Directory with jsons generated by the test suite',
+    )
+    parser.add_argument('--out', required=True, help='Output html file path')
+    args = parser.parse_args()
+    main(args)

scripts/perf_report_template.html

@@ -0,0 +1,52 @@
+<!DOCTYPE html>
+<html>
+
+<body>
+    <style>
+        table,
+        th,
+        td {
+            border: 1px solid black;
+            border-collapse: collapse;
+        }
+
+        .positive {
+            background-color: rgba(0, 255, 0, 0.8)
+        }
+
+        .negative {
+            background-color: rgba(255, 0, 0, 0.65)
+        }
+    </style>
+
+    <h2>Zenith Performance Tests</h2>
+
+    {% for suit_name, suit_data in context.items() %}
+    <h3>Runs for {{ suit_name }} </h3>
+    <b>platform:</b> {{ suit_data.platform }}<br>
+    {% for common_column_name, common_column_value in suit_data.common_columns %}
+    <b>{{ common_column_name }}</b>: {{ common_column_value }}<br>
+    {% endfor %}
+    <br>
+
+    <table>
+        <tr>
+            <th>revision</th>
+            {% for column_name in suit_data.value_columns %}
+            <th>{{ column_name }}</th>
+            {% endfor %}
+        </tr>
+        {% for row in suit_data.rows %}
+        <tr>
+            <td><a href=https://github.com/zenithdb/zenith/commit/{{ row.revision }}>{{ row.revision[:6] }}</a></td>
+            {% for column_value in row.values %}
+            <td class="{{ column_value.color }}">{{ column_value.value }}{{column_value.ratio}}</td>
+            {% endfor %}
+        </tr>
+        {% endfor %}
+    </table>
+    {% endfor %}
+
+</body>
+
+</html>

test_runner/Pipfile

@@ -5,15 +5,26 @@ name = "pypi"
 
 [packages]
 pytest = ">=6.0.0"
-psycopg2 = "*"
 typing-extensions = "*"
 pyjwt = {extras = ["crypto"], version = "*"}
+requests = "*"
+pytest-xdist = "*"
+asyncpg = "*"
+cached-property = "*"
+psycopg2-binary = "*"
+jinja2 = "*"
 
 [dev-packages]
-yapf = "*"
+# Behavior may change slightly between versions. These are run continuously,
+# so we pin exact versions to avoid suprising breaks. Update if comfortable.
+yapf = "==0.31.0"
+mypy = "==0.910"
+# Non-pinned packages follow.
+pipenv = "*"
 flake8 = "*"
-mypy = "*"
+types-requests = "*"
+types-psycopg2 = "*"
 
 [requires]
-# we need at least 3.6, but pipenv doesn't allow to say this directly
+# we need at least 3.7, but pipenv doesn't allow to say this directly
 python_version = "3"

test_runner/Pipfile.lock

@@ -1,7 +1,7 @@
 {
     "_meta": {
         "hash": {
-            "sha256": "f60a966726bcc19670402ad3fa57396b5dacf0a027544418ceb7cc0d42d94a52"
+            "sha256": "c309cb963a7b07ae3d30e9cbf08b495f77bdecc0e5356fc89d133c4fbcb65b2b"
         },
         "pipfile-spec": 6,
         "requires": {
@@ -16,6 +16,25 @@
         ]
     },
     "default": {
+        "asyncpg": {
+            "hashes": [
+                "sha256:129d501f3d30616afd51eb8d3142ef51ba05374256bd5834cec3ef4956a9b317",
+                "sha256:29ef6ae0a617fc13cc2ac5dc8e9b367bb83cba220614b437af9b67766f4b6b20",
+                "sha256:41704c561d354bef01353835a7846e5606faabbeb846214dfcf666cf53319f18",
+                "sha256:556b0e92e2b75dc028b3c4bc9bd5162ddf0053b856437cf1f04c97f9c6837d03",
+                "sha256:8ff5073d4b654e34bd5eaadc01dc4d68b8a9609084d835acd364cd934190a08d",
+                "sha256:a458fc69051fbb67d995fdda46d75a012b5d6200f91e17d23d4751482640ed4c",
+                "sha256:a7095890c96ba36f9f668eb552bb020dddb44f8e73e932f8573efc613ee83843",
+                "sha256:a738f4807c853623d3f93f0fea11f61be6b0e5ca16ea8aeb42c2c7ee742aa853",
+                "sha256:c4fc0205fe4ddd5aeb3dfdc0f7bafd43411181e1f5650189608e5971cceacff1",
+                "sha256:dd2fa063c3344823487d9ddccb40802f02622ddf8bf8a6cc53885ee7a2c1c0c6",
+                "sha256:ddffcb85227bf39cd1bedd4603e0082b243cf3b14ced64dce506a15b05232b83",
+                "sha256:e36c6806883786b19551bb70a4882561f31135dc8105a59662e0376cf5b2cbc5",
+                "sha256:eed43abc6ccf1dc02e0d0efc06ce46a411362f3358847c6b0ec9a43426f91ece"
+            ],
+            "index": "pypi",
+            "version": "==0.24.0"
+        },
         "attrs": {
             "hashes": [
                 "sha256:149e90d6d8ac20db7a955ad60cf0e6881a3f20d37096140088356da6c716b0b1",
@@ -24,72 +43,132 @@
             "markers": "python_version >= '2.7' and python_version not in '3.0, 3.1, 3.2, 3.3, 3.4'",
             "version": "==21.2.0"
         },
+        "cached-property": {
+            "hashes": [
+                "sha256:9fa5755838eecbb2d234c3aa390bd80fbd3ac6b6869109bfc1b499f7bd89a130",
+                "sha256:df4f613cf7ad9a588cc381aaf4a512d26265ecebd5eb9e1ba12f1319eb85a6a0"
+            ],
+            "index": "pypi",
+            "version": "==1.5.2"
+        },
+        "certifi": {
+            "hashes": [
+                "sha256:78884e7c1d4b00ce3cea67b44566851c4343c120abd683433ce934a68ea58872",
+                "sha256:d62a0163eb4c2344ac042ab2bdf75399a71a2d8c7d47eac2e2ee91b9d6339569"
+            ],
+            "version": "==2021.10.8"
+        },
         "cffi": {
             "hashes": [
-                "sha256:06c54a68935738d206570b20da5ef2b6b6d92b38ef3ec45c5422c0ebaf338d4d",
-                "sha256:0c0591bee64e438883b0c92a7bed78f6290d40bf02e54c5bf0978eaf36061771",
-                "sha256:19ca0dbdeda3b2615421d54bef8985f72af6e0c47082a8d26122adac81a95872",
-                "sha256:22b9c3c320171c108e903d61a3723b51e37aaa8c81255b5e7ce102775bd01e2c",
-                "sha256:26bb2549b72708c833f5abe62b756176022a7b9a7f689b571e74c8478ead51dc",
-                "sha256:33791e8a2dc2953f28b8d8d300dde42dd929ac28f974c4b4c6272cb2955cb762",
-                "sha256:3c8d896becff2fa653dc4438b54a5a25a971d1f4110b32bd3068db3722c80202",
-                "sha256:4373612d59c404baeb7cbd788a18b2b2a8331abcc84c3ba40051fcd18b17a4d5",
-                "sha256:487d63e1454627c8e47dd230025780e91869cfba4c753a74fda196a1f6ad6548",
-                "sha256:48916e459c54c4a70e52745639f1db524542140433599e13911b2f329834276a",
-                "sha256:4922cd707b25e623b902c86188aca466d3620892db76c0bdd7b99a3d5e61d35f",
-                "sha256:55af55e32ae468e9946f741a5d51f9896da6b9bf0bbdd326843fec05c730eb20",
-                "sha256:57e555a9feb4a8460415f1aac331a2dc833b1115284f7ded7278b54afc5bd218",
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+                "sha256:91d77d2a782be4274da750752bb1650a97bfd8f291022b379bb8e01c66b4e96b",
+                "sha256:91ec59c33514b7c7559a6acda53bbfe1b283949c34fe7440bcf917f96ac0723e",
+                "sha256:920f0d66a896c2d99f0adbb391f990a84091179542c205fa53ce5787aff87954",
+                "sha256:a5263e363c27b653a90078143adb3d076c1a748ec9ecc78ea2fb916f9b861962",
+                "sha256:abb9a20a72ac4e0fdb50dae135ba5e77880518e742077ced47eb1499e29a443c",
+                "sha256:c2051981a968d7de9dd2d7b87bcb9c939c74a34626a6e2f8181455dd49ed69e4",
+                "sha256:c21c9e3896c23007803a875460fb786118f0cdd4434359577ea25eb556e34c55",
+                "sha256:c2502a1a03b6312837279c8c1bd3ebedf6c12c4228ddbad40912d671ccc8a962",
+                "sha256:d4d692a89c5cf08a8557fdeb329b82e7bf609aadfaed6c0d79f5a449a3c7c023",
+                "sha256:da5db4e883f1ce37f55c667e5c0de439df76ac4cb55964655906306918e7363c",
+                "sha256:e7022a66d9b55e93e1a845d8c9eba2a1bebd4966cd8bfc25d9cd07d515b33fa6",
+                "sha256:ef1f279350da2c586a69d32fc8733092fd32cc8ac95139a00377841f59a3f8d8",
+                "sha256:f54a64f8b0c8ff0b64d18aa76675262e1700f3995182267998c31ae974fbc382",
+                "sha256:f5c7150ad32ba43a07c4479f40241756145a1f03b43480e058cfd862bf5041c7",
+                "sha256:f6f824dc3bce0edab5f427efcfb1d63ee75b6fcb7282900ccaf925be84efb0fc",
+                "sha256:fd8a250edc26254fe5b33be00402e6d287f562b6a5b2152dec302fa15bb3e997",
+                "sha256:ffaa5c925128e29efbde7301d8ecaf35c8c60ffbcd6a1ffd3a552177c8e5e796"
             ],
-            "version": "==1.14.6"
+            "version": "==1.15.0"
+        },
+        "charset-normalizer": {
+            "hashes": [
+                "sha256:e019de665e2bcf9c2b64e2e5aa025fa991da8720daa3c1138cadd2fd1856aed0",
+                "sha256:f7af805c321bfa1ce6714c51f254e0d5bb5e5834039bc17db7ebe3a4cec9492b"
+            ],
+            "markers": "python_version >= '3'",
+            "version": "==2.0.7"
         },
         "cryptography": {
             "hashes": [
-                "sha256:0f1212a66329c80d68aeeb39b8a16d54ef57071bf22ff4e521657b27372e327d",
-                "sha256:1e056c28420c072c5e3cb36e2b23ee55e260cb04eee08f702e0edfec3fb51959",
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+            "version": "==35.0.0"
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@@ -98,33 +177,141 @@
             ],
             "version": "==1.1.1"
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@@ -150,11 +337,11 @@
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             ],
             "hashes": [
-                "sha256:934d73fbba91b0483d3857d1aff50e96b2a892384ee2c17417ed3203f173fca1",
-                "sha256:fba44e7898bbca160a2b2b501f492824fc8382485d3a6f11ba5d0c1937ce6130"
+                "sha256:b888b4d56f06f6dcd777210c334e69c737be74755d3e5e9ee3fe67dc18a0ee41",
+                "sha256:e0c4bb8d9f0af0c7f5b1ec4c5036309617d03d56932877f2f7a0beeb5318322f"
             ],
             "index": "pypi",
-            "version": "==2.1.0"
+            "version": "==2.3.0"
         },
         "pyparsing": {
             "hashes": [
@@ -166,11 +353,35 @@
         },
         "pytest": {
             "hashes": [
-                "sha256:50bcad0a0b9c5a72c8e4e7c9855a3ad496ca6a881a3641b4260605450772c54b",
-                "sha256:91ef2131a9bd6be8f76f1f08eac5c5317221d6ad1e143ae03894b862e8976890"
+                "sha256:131b36680866a76e6781d13f101efb86cf674ebb9762eb70d3082b6f29889e89",
+                "sha256:7310f8d27bc79ced999e760ca304d69f6ba6c6649c0b60fb0e04a4a77cacc134"
             ],
             "index": "pypi",
-            "version": "==6.2.4"
+            "version": "==6.2.5"
+        },
+        "pytest-forked": {
+            "hashes": [
+                "sha256:6aa9ac7e00ad1a539c41bec6d21011332de671e938c7637378ec9710204e37ca",
+                "sha256:dc4147784048e70ef5d437951728825a131b81714b398d5d52f17c7c144d8815"
+            ],
+            "markers": "python_version >= '2.7' and python_version not in '3.0, 3.1, 3.2, 3.3, 3.4'",
+            "version": "==1.3.0"
+        },
+        "pytest-xdist": {
+            "hashes": [
+                "sha256:7b61ebb46997a0820a263553179d6d1e25a8c50d8a8620cd1aa1e20e3be99168",
+                "sha256:89b330316f7fc475f999c81b577c2b926c9569f3d397ae432c0c2e2496d61ff9"
+            ],
+            "index": "pypi",
+            "version": "==2.4.0"
+        },
+        "requests": {
+            "hashes": [
+                "sha256:6c1246513ecd5ecd4528a0906f910e8f0f9c6b8ec72030dc9fd154dc1a6efd24",
+                "sha256:b8aa58f8cf793ffd8782d3d8cb19e66ef36f7aba4353eec859e74678b01b07a7"
+            ],
+            "index": "pypi",
+            "version": "==2.26.0"
         },
         "toml": {
             "hashes": [
@@ -182,22 +393,76 @@
         },
         "typing-extensions": {
             "hashes": [
-                "sha256:0ac0f89795dd19de6b97debb0c6af1c70987fd80a2d62d1958f7e56fcc31b497",
-                "sha256:50b6f157849174217d0656f99dc82fe932884fb250826c18350e159ec6cdf342",
-                "sha256:779383f6086d90c99ae41cf0ff39aac8a7937a9283ce0a414e5dd782f4c94a84"
+                "sha256:49f75d16ff11f1cd258e1b988ccff82a3ca5570217d7ad8c5f48205dd99a677e",
+                "sha256:d8226d10bc02a29bcc81df19a26e56a9647f8b0a6d4a83924139f4a8b01f17b7",
+                "sha256:f1d25edafde516b146ecd0613dabcc61409817af4766fbbcfb8d1ad4ec441a34"
             ],
             "index": "pypi",
-            "version": "==3.10.0.0"
+            "version": "==3.10.0.2"
+        },
+        "urllib3": {
+            "hashes": [
+                "sha256:4987c65554f7a2dbf30c18fd48778ef124af6fab771a377103da0585e2336ece",
+                "sha256:c4fdf4019605b6e5423637e01bc9fe4daef873709a7973e195ceba0a62bbc844"
+            ],
+            "markers": "python_version >= '2.7' and python_version not in '3.0, 3.1, 3.2, 3.3, 3.4' and python_version < '4'",
+            "version": "==1.26.7"
+        },
+        "zipp": {
+            "hashes": [
+                "sha256:71c644c5369f4a6e07636f0aa966270449561fcea2e3d6747b8d23efaa9d7832",
+                "sha256:9fe5ea21568a0a70e50f273397638d39b03353731e6cbbb3fd8502a33fec40bc"
+            ],
+            "markers": "python_version >= '3.6'",
+            "version": "==3.6.0"
         }
     },
     "develop": {
+        "backports.entry-points-selectable": {
+            "hashes": [
+                "sha256:988468260ec1c196dab6ae1149260e2f5472c9110334e5d51adcb77867361f6a",
+                "sha256:a6d9a871cde5e15b4c4a53e3d43ba890cc6861ec1332c9c2428c92f977192acc"
+            ],
+            "markers": "python_version >= '2.7'",
+            "version": "==1.1.0"
+        },
+        "certifi": {
+            "hashes": [
+                "sha256:78884e7c1d4b00ce3cea67b44566851c4343c120abd683433ce934a68ea58872",
+                "sha256:d62a0163eb4c2344ac042ab2bdf75399a71a2d8c7d47eac2e2ee91b9d6339569"
+            ],
+            "version": "==2021.10.8"
+        },
+        "distlib": {
+            "hashes": [
+                "sha256:c8b54e8454e5bf6237cc84c20e8264c3e991e824ef27e8f1e81049867d861e31",
+                "sha256:d982d0751ff6eaaab5e2ec8e691d949ee80eddf01a62eaa96ddb11531fe16b05"
+            ],
+            "version": "==0.3.3"
+        },
+        "filelock": {
+            "hashes": [
+                "sha256:7afc856f74fa7006a289fd10fa840e1eebd8bbff6bffb69c26c54a0512ea8cf8",
+                "sha256:bb2a1c717df74c48a2d00ed625e5a66f8572a3a30baacb7657add1d7bac4097b"
+            ],
+            "markers": "python_version >= '3.6'",
+            "version": "==3.3.2"
+        },
         "flake8": {
             "hashes": [
-                "sha256:07528381786f2a6237b061f6e96610a4167b226cb926e2aa2b6b1d78057c576b",
-                "sha256:bf8fd333346d844f616e8d47905ef3a3384edae6b4e9beb0c5101e25e3110907"
+                "sha256:479b1304f72536a55948cb40a32dce8bb0ffe3501e26eaf292c7e60eb5e0428d",
+                "sha256:806e034dda44114815e23c16ef92f95c91e4c71100ff52813adf7132a6ad870d"
             ],
             "index": "pypi",
-            "version": "==3.9.2"
+            "version": "==4.0.1"
+        },
+        "importlib-metadata": {
+            "hashes": [
+                "sha256:b618b6d2d5ffa2f16add5697cf57a46c76a56229b0ed1c438322e4e95645bd15",
+                "sha256:f284b3e11256ad1e5d03ab86bb2ccd6f5339688ff17a4d797a0fe7df326f23b1"
+            ],
+            "markers": "python_version < '3.8'",
+            "version": "==4.8.1"
         },
         "mccabe": {
             "hashes": [
@@ -242,21 +507,45 @@
             ],
             "version": "==0.4.3"
         },
+        "pipenv": {
+            "hashes": [
+                "sha256:05958fadcd70b2de6a27542fcd2bd72dd5c59c6d35307fdac3e06361fb06e30e",
+                "sha256:d180f5be4775c552fd5e69ae18a9d6099d9dafb462efe54f11c72cb5f4d5e977"
+            ],
+            "index": "pypi",
+            "version": "==2021.5.29"
+        },
+        "platformdirs": {
+            "hashes": [
+                "sha256:367a5e80b3d04d2428ffa76d33f124cf11e8fff2acdaa9b43d545f5c7d661ef2",
+                "sha256:8868bbe3c3c80d42f20156f22e7131d2fb321f5bc86a2a345375c6481a67021d"
+            ],
+            "markers": "python_version >= '3.6'",
+            "version": "==2.4.0"
+        },
         "pycodestyle": {
             "hashes": [
-                "sha256:514f76d918fcc0b55c6680472f0a37970994e07bbb80725808c17089be302068",
-                "sha256:c389c1d06bf7904078ca03399a4816f974a1d590090fecea0c63ec26ebaf1cef"
+                "sha256:720f8b39dde8b293825e7ff02c475f3077124006db4f440dcbc9a20b76548a20",
+                "sha256:eddd5847ef438ea1c7870ca7eb78a9d47ce0cdb4851a5523949f2601d0cbbe7f"
             ],
-            "markers": "python_version >= '2.7' and python_version not in '3.0, 3.1, 3.2, 3.3'",
-            "version": "==2.7.0"
+            "markers": "python_version >= '2.7' and python_version not in '3.0, 3.1, 3.2, 3.3, 3.4'",
+            "version": "==2.8.0"
         },
         "pyflakes": {
             "hashes": [
-                "sha256:7893783d01b8a89811dd72d7dfd4d84ff098e5eed95cfa8905b22bbffe52efc3",
-                "sha256:f5bc8ecabc05bb9d291eb5203d6810b49040f6ff446a756326104746cc00c1db"
+                "sha256:05a85c2872edf37a4ed30b0cce2f6093e1d0581f8c19d7393122da7e25b2b24c",
+                "sha256:3bb3a3f256f4b7968c9c788781e4ff07dce46bdf12339dcda61053375426ee2e"
             ],
             "markers": "python_version >= '2.7' and python_version not in '3.0, 3.1, 3.2, 3.3'",
-            "version": "==2.3.1"
+            "version": "==2.4.0"
+        },
+        "six": {
+            "hashes": [
+                "sha256:1e61c37477a1626458e36f7b1d82aa5c9b094fa4802892072e49de9c60c4c926",
+                "sha256:8abb2f1d86890a2dfb989f9a77cfcfd3e47c2a354b01111771326f8aa26e0254"
+            ],
+            "markers": "python_version >= '2.7' and python_version not in '3.0, 3.1, 3.2, 3.3'",
+            "version": "==1.16.0"
         },
         "toml": {
             "hashes": [
@@ -266,14 +555,82 @@
             "markers": "python_version >= '2.6' and python_version not in '3.0, 3.1, 3.2, 3.3'",
             "version": "==0.10.2"
         },
-        "typing-extensions": {
+        "typed-ast": {
             "hashes": [
-                "sha256:0ac0f89795dd19de6b97debb0c6af1c70987fd80a2d62d1958f7e56fcc31b497",
-                "sha256:50b6f157849174217d0656f99dc82fe932884fb250826c18350e159ec6cdf342",
-                "sha256:779383f6086d90c99ae41cf0ff39aac8a7937a9283ce0a414e5dd782f4c94a84"
+                "sha256:01ae5f73431d21eead5015997ab41afa53aa1fbe252f9da060be5dad2c730ace",
+                "sha256:067a74454df670dcaa4e59349a2e5c81e567d8d65458d480a5b3dfecec08c5ff",
+                "sha256:0fb71b8c643187d7492c1f8352f2c15b4c4af3f6338f21681d3681b3dc31a266",
+                "sha256:1b3ead4a96c9101bef08f9f7d1217c096f31667617b58de957f690c92378b528",
+                "sha256:2068531575a125b87a41802130fa7e29f26c09a2833fea68d9a40cf33902eba6",
+                "sha256:209596a4ec71d990d71d5e0d312ac935d86930e6eecff6ccc7007fe54d703808",
+                "sha256:2c726c276d09fc5c414693a2de063f521052d9ea7c240ce553316f70656c84d4",
+                "sha256:398e44cd480f4d2b7ee8d98385ca104e35c81525dd98c519acff1b79bdaac363",
+                "sha256:52b1eb8c83f178ab787f3a4283f68258525f8d70f778a2f6dd54d3b5e5fb4341",
+                "sha256:5feca99c17af94057417d744607b82dd0a664fd5e4ca98061480fd8b14b18d04",
+                "sha256:7538e495704e2ccda9b234b82423a4038f324f3a10c43bc088a1636180f11a41",
+                "sha256:760ad187b1041a154f0e4d0f6aae3e40fdb51d6de16e5c99aedadd9246450e9e",
+                "sha256:777a26c84bea6cd934422ac2e3b78863a37017618b6e5c08f92ef69853e765d3",
+                "sha256:95431a26309a21874005845c21118c83991c63ea800dd44843e42a916aec5899",
+                "sha256:9ad2c92ec681e02baf81fdfa056fe0d818645efa9af1f1cd5fd6f1bd2bdfd805",
+                "sha256:9c6d1a54552b5330bc657b7ef0eae25d00ba7ffe85d9ea8ae6540d2197a3788c",
+                "sha256:aee0c1256be6c07bd3e1263ff920c325b59849dc95392a05f258bb9b259cf39c",
+                "sha256:af3d4a73793725138d6b334d9d247ce7e5f084d96284ed23f22ee626a7b88e39",
+                "sha256:b36b4f3920103a25e1d5d024d155c504080959582b928e91cb608a65c3a49e1a",
+                "sha256:b9574c6f03f685070d859e75c7f9eeca02d6933273b5e69572e5ff9d5e3931c3",
+                "sha256:bff6ad71c81b3bba8fa35f0f1921fb24ff4476235a6e94a26ada2e54370e6da7",
+                "sha256:c190f0899e9f9f8b6b7863debfb739abcb21a5c054f911ca3596d12b8a4c4c7f",
+                "sha256:c907f561b1e83e93fad565bac5ba9c22d96a54e7ea0267c708bffe863cbe4075",
+                "sha256:cae53c389825d3b46fb37538441f75d6aecc4174f615d048321b716df2757fb0",
+                "sha256:dd4a21253f42b8d2b48410cb31fe501d32f8b9fbeb1f55063ad102fe9c425e40",
+                "sha256:dde816ca9dac1d9c01dd504ea5967821606f02e510438120091b84e852367428",
+                "sha256:f2362f3cb0f3172c42938946dbc5b7843c2a28aec307c49100c8b38764eb6927",
+                "sha256:f328adcfebed9f11301eaedfa48e15bdece9b519fb27e6a8c01aa52a17ec31b3",
+                "sha256:f8afcf15cc511ada719a88e013cec87c11aff7b91f019295eb4530f96fe5ef2f",
+                "sha256:fb1bbeac803adea29cedd70781399c99138358c26d05fcbd23c13016b7f5ec65"
+            ],
+            "markers": "python_version < '3.8'",
+            "version": "==1.4.3"
+        },
+        "types-psycopg2": {
+            "hashes": [
+                "sha256:77ed80f2668582654623e04fb3d741ecce93effcc39c929d7e02f4a917a538ce",
+                "sha256:98a6e0e9580cd7eb4bd4d20f7c7063d154b2589a2b90c0ce4e3ca6085cde77c6"
             ],
             "index": "pypi",
-            "version": "==3.10.0.0"
+            "version": "==2.9.1"
+        },
+        "types-requests": {
+            "hashes": [
+                "sha256:b279284e51f668e38ee12d9665e4d789089f532dc2a0be4a1508ca0efd98ba9e",
+                "sha256:ba1d108d512e294b6080c37f6ae7cb2a2abf527560e2b671d1786c1fc46b541a"
+            ],
+            "index": "pypi",
+            "version": "==2.25.11"
+        },
+        "typing-extensions": {
+            "hashes": [
+                "sha256:49f75d16ff11f1cd258e1b988ccff82a3ca5570217d7ad8c5f48205dd99a677e",
+                "sha256:d8226d10bc02a29bcc81df19a26e56a9647f8b0a6d4a83924139f4a8b01f17b7",
+                "sha256:f1d25edafde516b146ecd0613dabcc61409817af4766fbbcfb8d1ad4ec441a34"
+            ],
+            "index": "pypi",
+            "version": "==3.10.0.2"
+        },
+        "virtualenv": {
+            "hashes": [
+                "sha256:4b02e52a624336eece99c96e3ab7111f469c24ba226a53ec474e8e787b365814",
+                "sha256:576d05b46eace16a9c348085f7d0dc8ef28713a2cabaa1cf0aea41e8f12c9218"
+            ],
+            "markers": "python_version >= '2.7' and python_version not in '3.0, 3.1, 3.2, 3.3, 3.4'",
+            "version": "==20.10.0"
+        },
+        "virtualenv-clone": {
+            "hashes": [
+                "sha256:418ee935c36152f8f153c79824bb93eaf6f0f7984bae31d3f48f350b9183501a",
+                "sha256:44d5263bceed0bac3e1424d64f798095233b64def1c5689afa43dc3223caf5b0"
+            ],
+            "markers": "python_version >= '2.7' and python_version not in '3.0, 3.1, 3.2, 3.3'",
+            "version": "==0.5.7"
         },
         "yapf": {
             "hashes": [
@@ -282,6 +639,14 @@
             ],
             "index": "pypi",
             "version": "==0.31.0"
+        },
+        "zipp": {
+            "hashes": [
+                "sha256:71c644c5369f4a6e07636f0aa966270449561fcea2e3d6747b8d23efaa9d7832",
+                "sha256:9fe5ea21568a0a70e50f273397638d39b03353731e6cbbb3fd8502a33fec40bc"
+            ],
+            "markers": "python_version >= '3.6'",
+            "version": "==3.6.0"
         }
     }
 }

test_runner/README.md

@@ -3,11 +3,15 @@
 This directory contains integration tests.
 
 Prerequisites:
-- Python 3.6 or later
+- Python 3.7 or later
+    - Development headers may also be needed to build `psycopg2` from source.
+    - Python 3.7 is recommended if you want to update tests.
 - Dependencies: install them via `pipenv install`. Note that Debian/Ubuntu
   packages are stale, as it commonly happens, so manual installation is not
   recommended.
-  Run `pipenv shell` to activate the venv.
+  Exact version of `pipenv` is not important unless you change dependencies.
+  Run `pipenv shell` to activate the venv or use `pipenv run` to run a single
+  command in the venv, e.g. `pipenv run pytest`.
 - Zenith and Postgres binaries
     - See the root README.md for build directions
     - Tests can be run from the git tree; or see the environment variables
@@ -52,8 +56,8 @@ Useful environment variables:
 should go.
 `TEST_SHARED_FIXTURES`: Try to re-use a single pageserver for all the tests.
 
-Let stdout and stderr go to the terminal instead of capturing them:
-`pytest -s ...`
+Let stdout, stderr and `INFO` log messages go to the terminal instead of capturing them:
+`pytest -s --log-cli-level=INFO ...`
 (Note many tests capture subprocess outputs separately, so this may not
 show much.)
 
@@ -61,44 +65,87 @@ Exit after the first test failure:
 `pytest -x ...`
 (there are many more pytest options; run `pytest -h` to see them.)
 
+### Writing a test
 
-### Building new tests
+Every test needs a Zenith Environment, or ZenithEnv to operate in. A Zenith Environment
+is like a little cloud-in-a-box, and consists of a Pageserver, 0-N Safekeepers, and
+compute Postgres nodes. The connections between them can be configured to use JWT
+authentication tokens, and some other configuration options can be tweaked too.
 
-The tests make heavy use of pytest fixtures. You can read about how they work here: https://docs.pytest.org/en/stable/fixture.html
+The easiest way to get access to a Zenith Environment is by using the `zenith_simple_env`
+fixture. The 'simple' env may be shared across multiple tests, so don't shut down the nodes
+or make other destructive changes in that environment. Also don't assume that
+there are no tenants or branches or data in the cluster. For convenience, there is a
+branch called `empty`, though. The convention is to create a test-specific branch of
+that and load any test data there, instead of the 'main' branch.
 
-Essentially, this means that each time you see a fixture named as an input parameter, the function with that name will be run and passed as a parameter to the function.
-
-So this code:
+For more complicated cases, you can build a custom Zenith Environment, with the `zenith_env`
+fixture:
 
 ```python
-def test_something(zenith_cli, pg_bin):
-    pass
+def test_foobar(zenith_env_builder: ZenithEnvBuilder):
+    # Prescribe the environment.
+    # We want to have 3 safekeeper nodes, and use JWT authentication in the
+    # connections to the page server
+    zenith_env_builder.num_safekeepers = 3
+    zenith_env_builder.set_pageserver_auth(True)
+
+    # Now create the environment. This initializes the repository, and starts
+    # up the page server and the safekeepers
+    env = zenith_env_builder.init()
+
+    # Run the test
+    ...
 ```
 
-... will run the fixtures called `zenith_cli` and `pg_bin` and deliver those results to the test function.
+For more information about pytest fixtures, see https://docs.pytest.org/en/stable/fixture.html
 
-Fixtures can't be imported using the normal python syntax. Instead, use this:
+At the end of a test, all the nodes in the environment are automatically stopped, so you
+don't need to worry about cleaning up. Logs and test data are preserved for the analysis,
+in a directory under `../test_output/<testname>`
 
-```python
-pytest_plugins = ("fixtures.something")
+### Before submitting a patch
+#### Obligatory checks
+Install dev dependencies via `pipenv --python 3.7 install --dev` (better)
+or `pipenv install --dev` (if you don't have Python 3.7 and don't need to change dependencies).
+
+We force code formatting via yapf and type hints via mypy.
+Run the following commands in the `test_runner/` directory:
+
+```bash
+pipenv run yapf -ri .  # All code is reformatted
+pipenv run mypy .  # Ensure there are no typing errors
 ```
 
-That will make all the fixtures in the `fixtures/something.py` file available.
-
-Anything that's likely to be used in multiple tests should be built into a fixture.
-
-Note that fixtures can clean up after themselves if they use the `yield` syntax.
-Cleanup will happen even if the test fails (raises an unhandled exception).
-Python destructors, e.g. `__del__()` aren't recommended for cleanup.
-
-
-### Code quality
-
-Before submitting a patch, please consider:
-
+#### Advisable actions
 * Writing a couple of docstrings to clarify the reasoning behind a new test.
 * Running `flake8` (or a linter of your choice, e.g. `pycodestyle`) and fixing possible defects, if any.
-* Formatting the code with `yapf -r -i .` (TODO: implement an opt-in pre-commit hook for that).
-* (Optional) Typechecking the code with `mypy .`. Currently this mostly affects `fixtures/zenith_fixtures.py`.
+* Adding more type hints to your code to avoid `Any`, especially:
+  * For fixture parameters, they are not automatically deduced.
+  * For function arguments and return values.
 
-The tools can be installed with `pipenv install --dev`.
+#### Changing dependencies
+You have to update `Pipfile.lock` if you have changed `Pipfile`:
+
+```bash
+pipenv --python 3.7 install --dev  # Re-create venv for Python 3.7 and install recent pipenv inside
+pipenv run pipenv --version  # Should be at least 2021.5.29
+pipenv run pipenv lock  # Regenerate Pipfile.lock
+```
+
+As the minimal supported version is Python 3.7 and we use it in CI,
+you have to use a Python 3.7 environment when updating `Pipfile.lock`.
+Otherwise some back-compatibility packages will be missing.
+
+It is also important to run recent `pipenv`.
+Older versions remove markers from `Pipfile.lock`.
+
+If you don't have Python 3.7, you should install it and its headers (for `psycopg2`)
+separately, e.g.:
+
+```bash
+# In Ubuntu
+sudo add-apt-repository ppa:deadsnakes/ppa
+sudo apt update
+sudo apt install python3.7 python3.7-dev
+```

test_runner/batch_others/test_auth.py

@@ -1,61 +1,22 @@
-
 from contextlib import closing
-from pathlib import Path
+from typing import Iterator
 from uuid import uuid4
-from dataclasses import dataclass
-import jwt
 import psycopg2
-from fixtures.zenith_fixtures import Postgres, ZenithCli, ZenithPageserver
+from fixtures.zenith_fixtures import ZenithEnvBuilder
 import pytest
 
-
-@pytest.fixture
-def pageserver_auth_enabled(zenith_cli: ZenithCli):
-    with ZenithPageserver(zenith_cli).init(enable_auth=True).start() as ps:
-        # For convenience in tests, create a branch from the freshly-initialized cluster.
-        zenith_cli.run(["branch", "empty", "main"])
-        yield ps
+pytest_plugins = ("fixtures.zenith_fixtures")
 
 
-@dataclass
-class AuthKeys:
-    pub: bytes
-    priv: bytes
+def test_pageserver_auth(zenith_env_builder: ZenithEnvBuilder):
+    zenith_env_builder.pageserver_auth_enabled = True
+    env = zenith_env_builder.init()
 
-    def generate_management_token(self):
-        token = jwt.encode({"scope": "pageserverapi"}, self.priv, algorithm="RS256")
+    ps = env.pageserver
 
-        # jwt.encode can return 'bytes' or 'str', depending on Python version or type
-        # hinting or something (not sure what). If it returned 'bytes', convert it to 'str'
-        # explicitly.
-        if isinstance(token, bytes):
-            token = token.decode()
-
-        return token
-
-    def generate_tenant_token(self, tenant_id):
-        token = jwt.encode({"scope": "tenant", "tenant_id": tenant_id}, self.priv, algorithm="RS256")
-
-        if isinstance(token, bytes):
-            token = token.decode()
-
-        return token
-
-
-@pytest.fixture
-def auth_keys(repo_dir: str) -> AuthKeys:
-    # TODO probably this should be specified in cli config and used in tests for single source of truth
-    pub = (Path(repo_dir) / 'auth_public_key.pem').read_bytes()
-    priv = (Path(repo_dir) / 'auth_private_key.pem').read_bytes()
-    return AuthKeys(pub=pub, priv=priv)
-
-
-def test_pageserver_auth(pageserver_auth_enabled: ZenithPageserver, auth_keys: AuthKeys):
-    ps = pageserver_auth_enabled
-
-    tenant_token = auth_keys.generate_tenant_token(ps.initial_tenant)
-    invalid_tenant_token = auth_keys.generate_tenant_token(uuid4().hex)
-    management_token = auth_keys.generate_management_token()
+    tenant_token = env.auth_keys.generate_tenant_token(env.initial_tenant)
+    invalid_tenant_token = env.auth_keys.generate_tenant_token(uuid4().hex)
+    management_token = env.auth_keys.generate_management_token()
 
     # this does not invoke auth check and only decodes jwt and checks it for validity
     # check both tokens
@@ -63,55 +24,41 @@ def test_pageserver_auth(pageserver_auth_enabled: ZenithPageserver, auth_keys: A
     ps.safe_psql("status", password=management_token)
 
     # tenant can create branches
-    ps.safe_psql(f"branch_create {ps.initial_tenant} new1 main", password=tenant_token)
+    ps.safe_psql(f"branch_create {env.initial_tenant} new1 main", password=tenant_token)
     # console can create branches for tenant
-    ps.safe_psql(f"branch_create {ps.initial_tenant} new2 main", password=management_token)
+    ps.safe_psql(f"branch_create {env.initial_tenant} new2 main", password=management_token)
 
     # fail to create branch using token with different tenantid
     with pytest.raises(psycopg2.DatabaseError, match='Tenant id mismatch. Permission denied'):
-        ps.safe_psql(f"branch_create {ps.initial_tenant} new2 main", password=invalid_tenant_token)
+        ps.safe_psql(f"branch_create {env.initial_tenant} new2 main", password=invalid_tenant_token)
 
     # create tenant using management token
     ps.safe_psql(f"tenant_create {uuid4().hex}", password=management_token)
 
     # fail to create tenant using tenant token
-    with pytest.raises(psycopg2.DatabaseError, match='Attempt to access management api with tenant scope. Permission denied'):
+    with pytest.raises(
+            psycopg2.DatabaseError,
+            match='Attempt to access management api with tenant scope. Permission denied'):
         ps.safe_psql(f"tenant_create {uuid4().hex}", password=tenant_token)
 
 
 @pytest.mark.parametrize('with_wal_acceptors', [False, True])
-def test_compute_auth_to_pageserver(
-    zenith_cli: ZenithCli,
-    wa_factory,
-    pageserver_auth_enabled: ZenithPageserver,
-    repo_dir: str,
-    with_wal_acceptors: bool,
-    auth_keys: AuthKeys,
-):
-    ps = pageserver_auth_enabled
-    # since we are in progress of refactoring protocols between compute safekeeper and page server
-    # use hardcoded management token in safekeeper
-    management_token = auth_keys.generate_management_token()
+def test_compute_auth_to_pageserver(zenith_env_builder: ZenithEnvBuilder, with_wal_acceptors: bool):
+    zenith_env_builder.pageserver_auth_enabled = True
+    if with_wal_acceptors:
+        zenith_env_builder.num_safekeepers = 3
+    env = zenith_env_builder.init()
 
     branch = f"test_compute_auth_to_pageserver{with_wal_acceptors}"
-    zenith_cli.run(["branch", branch, "empty"])
-    if with_wal_acceptors:
-        wa_factory.start_n_new(3, management_token)
+    env.zenith_cli(["branch", branch, "main"])
 
-    with Postgres(
-        zenith_cli=zenith_cli,
-        repo_dir=repo_dir,
-        tenant_id=ps.initial_tenant,
-        port=55432, # FIXME port distribution is hardcoded in tests and in cli
-    ).create_start(
-        branch,
-        wal_acceptors=wa_factory.get_connstrs() if with_wal_acceptors else None,
-    ) as pg:
-        with closing(pg.connect()) as conn:
-            with conn.cursor() as cur:
-                # we rely upon autocommit after each statement
-                # as waiting for acceptors happens there
-                cur.execute('CREATE TABLE t(key int primary key, value text)')
-                cur.execute("INSERT INTO t SELECT generate_series(1,100000), 'payload'")
-                cur.execute('SELECT sum(key) FROM t')
-                assert cur.fetchone() == (5000050000, )
+    pg = env.postgres.create_start(branch)
+
+    with closing(pg.connect()) as conn:
+        with conn.cursor() as cur:
+            # we rely upon autocommit after each statement
+            # as waiting for acceptors happens there
+            cur.execute('CREATE TABLE t(key int primary key, value text)')
+            cur.execute("INSERT INTO t SELECT generate_series(1,100000), 'payload'")
+            cur.execute('SELECT sum(key) FROM t')
+            assert cur.fetchone() == (5000050000, )

test_runner/batch_others/test_branch_behind.py

@@ -1,5 +1,6 @@
-from fixtures.zenith_fixtures import PostgresFactory, ZenithPageserver
-
+import subprocess
+from fixtures.zenith_fixtures import ZenithEnv
+from fixtures.log_helper import log
 
 pytest_plugins = ("fixtures.zenith_fixtures")
 
@@ -7,12 +8,13 @@ pytest_plugins = ("fixtures.zenith_fixtures")
 #
 # Create a couple of branches off the main branch, at a historical point in time.
 #
-def test_branch_behind(zenith_cli, pageserver: ZenithPageserver, postgres: PostgresFactory, pg_bin):
+def test_branch_behind(zenith_simple_env: ZenithEnv):
+    env = zenith_simple_env
     # Branch at the point where only 100 rows were inserted
-    zenith_cli.run(["branch", "test_branch_behind", "empty"])
+    env.zenith_cli(["branch", "test_branch_behind", "empty"])
 
-    pgmain = postgres.create_start('test_branch_behind')
-    print("postgres is running on 'test_branch_behind' branch")
+    pgmain = env.postgres.create_start('test_branch_behind')
+    log.info("postgres is running on 'test_branch_behind' branch")
 
     main_pg_conn = pgmain.connect()
     main_cur = main_pg_conn.cursor()
@@ -26,38 +28,38 @@ def test_branch_behind(zenith_cli, pageserver: ZenithPageserver, postgres: Postg
     ''')
     main_cur.execute('SELECT pg_current_wal_insert_lsn()')
     lsn_a = main_cur.fetchone()[0]
-    print('LSN after 100 rows: ' + lsn_a)
+    log.info(f'LSN after 100 rows: {lsn_a}')
 
     # Insert some more rows. (This generates enough WAL to fill a few segments.)
     main_cur.execute('''
         INSERT INTO foo
             SELECT 'long string to consume some space' || g
-            FROM generate_series(1, 100000) g
+            FROM generate_series(1, 200000) g
     ''')
     main_cur.execute('SELECT pg_current_wal_insert_lsn()')
     lsn_b = main_cur.fetchone()[0]
-    print('LSN after 100100 rows: ' + lsn_b)
+    log.info(f'LSN after 200100 rows: {lsn_b}')
 
     # Branch at the point where only 100 rows were inserted
-    zenith_cli.run(["branch", "test_branch_behind_hundred", "test_branch_behind@" + lsn_a])
+    env.zenith_cli(["branch", "test_branch_behind_hundred", "test_branch_behind@" + lsn_a])
 
     # Insert many more rows. This generates enough WAL to fill a few segments.
     main_cur.execute('''
         INSERT INTO foo
             SELECT 'long string to consume some space' || g
-            FROM generate_series(1, 100000) g
+            FROM generate_series(1, 200000) g
     ''')
     main_cur.execute('SELECT pg_current_wal_insert_lsn()')
 
     main_cur.execute('SELECT pg_current_wal_insert_lsn()')
     lsn_c = main_cur.fetchone()[0]
-    print('LSN after 200100 rows: ' + lsn_c)
+    log.info(f'LSN after 400100 rows: {lsn_c}')
 
-    # Branch at the point where only 200 rows were inserted
-    zenith_cli.run(["branch", "test_branch_behind_more", "test_branch_behind@" + lsn_b])
+    # Branch at the point where only 200100 rows were inserted
+    env.zenith_cli(["branch", "test_branch_behind_more", "test_branch_behind@" + lsn_b])
 
-    pg_hundred = postgres.create_start("test_branch_behind_hundred")
-    pg_more = postgres.create_start("test_branch_behind_more")
+    pg_hundred = env.postgres.create_start("test_branch_behind_hundred")
+    pg_more = env.postgres.create_start("test_branch_behind_more")
 
     # On the 'hundred' branch, we should see only 100 rows
     hundred_pg_conn = pg_hundred.connect()
@@ -69,8 +71,26 @@ def test_branch_behind(zenith_cli, pageserver: ZenithPageserver, postgres: Postg
     more_pg_conn = pg_more.connect()
     more_cur = more_pg_conn.cursor()
     more_cur.execute('SELECT count(*) FROM foo')
-    assert more_cur.fetchone() == (100100, )
+    assert more_cur.fetchone() == (200100, )
 
     # All the rows are visible on the main branch
     main_cur.execute('SELECT count(*) FROM foo')
-    assert main_cur.fetchone() == (200100, )
+    assert main_cur.fetchone() == (400100, )
+
+    # Check bad lsn's for branching
+
+    # branch at segment boundary
+    env.zenith_cli(["branch", "test_branch_segment_boundary", "test_branch_behind@0/3000000"])
+    pg = env.postgres.create_start("test_branch_segment_boundary")
+    cur = pg.connect().cursor()
+    cur.execute('SELECT 1')
+    assert cur.fetchone() == (1, )
+
+    # branch at pre-initdb lsn
+    #
+    # FIXME: This works currently, but probably shouldn't be allowed
+    try:
+        env.zenith_cli(["branch", "test_branch_preinitdb", "test_branch_behind@0/42"])
+        # FIXME: assert false, "branch with invalid LSN should have failed"
+    except subprocess.CalledProcessError:
+        log.info("Branch creation with pre-initdb LSN failed (as expected)")

test_runner/batch_others/test_clog_truncate.py

@@ -3,7 +3,8 @@ import os
 
 from contextlib import closing
 
-from fixtures.zenith_fixtures import PostgresFactory, ZenithPageserver
+from fixtures.zenith_fixtures import ZenithEnv
+from fixtures.log_helper import log
 
 pytest_plugins = ("fixtures.zenith_fixtures")
 
@@ -11,20 +12,24 @@ pytest_plugins = ("fixtures.zenith_fixtures")
 #
 # Test compute node start after clog truncation
 #
-def test_clog_truncate(zenith_cli, pageserver: ZenithPageserver, postgres: PostgresFactory, pg_bin):
+def test_clog_truncate(zenith_simple_env: ZenithEnv):
+    env = zenith_simple_env
     # Create a branch for us
-    zenith_cli.run(["branch", "test_clog_truncate", "empty"])
+    env.zenith_cli(["branch", "test_clog_truncate", "empty"])
 
     # set agressive autovacuum to make sure that truncation will happen
     config = [
-        'autovacuum_max_workers=10', 'autovacuum_vacuum_threshold=0',
-        'autovacuum_vacuum_insert_threshold=0', 'autovacuum_vacuum_cost_delay=0',
-        'autovacuum_vacuum_cost_limit=10000', 'autovacuum_naptime =1s',
+        'autovacuum_max_workers=10',
+        'autovacuum_vacuum_threshold=0',
+        'autovacuum_vacuum_insert_threshold=0',
+        'autovacuum_vacuum_cost_delay=0',
+        'autovacuum_vacuum_cost_limit=10000',
+        'autovacuum_naptime =1s',
         'autovacuum_freeze_max_age=100000'
     ]
 
-    pg = postgres.create_start('test_clog_truncate', config_lines=config)
-    print('postgres is running on test_clog_truncate branch')
+    pg = env.postgres.create_start('test_clog_truncate', config_lines=config)
+    log.info('postgres is running on test_clog_truncate branch')
 
     # Install extension containing function needed for test
     pg.safe_psql('CREATE EXTENSION zenith_test_utils')
@@ -33,22 +38,22 @@ def test_clog_truncate(zenith_cli, pageserver: ZenithPageserver, postgres: Postg
     with closing(pg.connect()) as conn:
         with conn.cursor() as cur:
             cur.execute('select test_consume_xids(1000*1000*10);')
-            print('xids consumed')
+            log.info('xids consumed')
 
             # call a checkpoint to trigger TruncateSubtrans
             cur.execute('CHECKPOINT;')
 
             # ensure WAL flush
             cur.execute('select txid_current()')
-            print(cur.fetchone())
+            log.info(cur.fetchone())
 
     # wait for autovacuum to truncate the pg_xact
     # XXX Is it worth to add a timeout here?
     pg_xact_0000_path = os.path.join(pg.pg_xact_dir_path(), '0000')
-    print("pg_xact_0000_path = " + pg_xact_0000_path)
+    log.info(f"pg_xact_0000_path = {pg_xact_0000_path}")
 
     while os.path.isfile(pg_xact_0000_path):
-        print("file exists. wait for truncation. " "pg_xact_0000_path = " + pg_xact_0000_path)
+        log.info(f"file exists. wait for truncation. " "pg_xact_0000_path = {pg_xact_0000_path}")
         time.sleep(5)
 
     # checkpoint to advance latest lsn
@@ -59,14 +64,14 @@ def test_clog_truncate(zenith_cli, pageserver: ZenithPageserver, postgres: Postg
             lsn_after_truncation = cur.fetchone()[0]
 
     # create new branch after clog truncation and start a compute node on it
-    print('create branch at lsn_after_truncation ' + lsn_after_truncation)
-    zenith_cli.run(
+    log.info(f'create branch at lsn_after_truncation {lsn_after_truncation}')
+    env.zenith_cli(
         ["branch", "test_clog_truncate_new", "test_clog_truncate@" + lsn_after_truncation])
 
-    pg2 = postgres.create_start('test_clog_truncate_new')
-    print('postgres is running on test_clog_truncate_new branch')
+    pg2 = env.postgres.create_start('test_clog_truncate_new')
+    log.info('postgres is running on test_clog_truncate_new branch')
 
     # check that new node doesn't contain truncated segment
     pg_xact_0000_path_new = os.path.join(pg2.pg_xact_dir_path(), '0000')
-    print("pg_xact_0000_path_new = " + pg_xact_0000_path_new)
+    log.info(f"pg_xact_0000_path_new = {pg_xact_0000_path_new}")
     assert os.path.isfile(pg_xact_0000_path_new) is False

test_runner/batch_others/test_config.py

@@ -1,6 +1,7 @@
 from contextlib import closing
 
-from fixtures.zenith_fixtures import PostgresFactory, ZenithPageserver
+from fixtures.zenith_fixtures import ZenithEnv
+from fixtures.log_helper import log
 
 pytest_plugins = ("fixtures.zenith_fixtures")
 
@@ -8,13 +9,14 @@ pytest_plugins = ("fixtures.zenith_fixtures")
 #
 # Test starting Postgres with custom options
 #
-def test_config(zenith_cli, pageserver: ZenithPageserver, postgres: PostgresFactory, pg_bin):
+def test_config(zenith_simple_env: ZenithEnv):
+    env = zenith_simple_env
     # Create a branch for us
-    zenith_cli.run(["branch", "test_config", "empty"])
+    env.zenith_cli(["branch", "test_config", "empty"])
 
     # change config
-    pg = postgres.create_start('test_config', config_lines=['log_min_messages=debug1'])
-    print('postgres is running on test_config branch')
+    pg = env.postgres.create_start('test_config', config_lines=['log_min_messages=debug1'])
+    log.info('postgres is running on test_config branch')
 
     with closing(pg.connect()) as conn:
         with conn.cursor() as cur:

test_runner/batch_others/test_createdb.py

@@ -1,38 +0,0 @@
-from contextlib import closing
-from fixtures.zenith_fixtures import ZenithPageserver, PostgresFactory, ZenithCli
-
-pytest_plugins = ("fixtures.zenith_fixtures")
-
-
-#
-# Test CREATE DATABASE when there have been relmapper changes
-#
-def test_createdb(
-    zenith_cli: ZenithCli,
-    pageserver: ZenithPageserver,
-    postgres: PostgresFactory,
-    pg_bin,
-):
-    zenith_cli.run(["branch", "test_createdb", "empty"])
-
-    pg = postgres.create_start('test_createdb')
-    print("postgres is running on 'test_createdb' branch")
-
-    with closing(pg.connect()) as conn:
-        with conn.cursor() as cur:
-            # Cause a 'relmapper' change in the original branch
-            cur.execute('VACUUM FULL pg_class')
-
-            cur.execute('CREATE DATABASE foodb')
-
-            cur.execute('SELECT pg_current_wal_insert_lsn()')
-            lsn = cur.fetchone()[0]
-
-    # Create a branch
-    zenith_cli.run(["branch", "test_createdb2", "test_createdb@" + lsn])
-
-    pg2 = postgres.create_start('test_createdb2')
-
-    # Test that you can connect to the new database on both branches
-    for db in (pg, pg2):
-        db.connect(dbname='foodb').close()

test_runner/batch_others/test_createdropdb.py

@@ -0,0 +1,95 @@
+import os
+import pathlib
+
+from contextlib import closing
+from fixtures.zenith_fixtures import ZenithEnv, check_restored_datadir_content
+from fixtures.log_helper import log
+
+pytest_plugins = ("fixtures.zenith_fixtures")
+
+
+#
+# Test CREATE DATABASE when there have been relmapper changes
+#
+def test_createdb(zenith_simple_env: ZenithEnv):
+    env = zenith_simple_env
+    env.zenith_cli(["branch", "test_createdb", "empty"])
+
+    pg = env.postgres.create_start('test_createdb')
+    log.info("postgres is running on 'test_createdb' branch")
+
+    with closing(pg.connect()) as conn:
+        with conn.cursor() as cur:
+            # Cause a 'relmapper' change in the original branch
+            cur.execute('VACUUM FULL pg_class')
+
+            cur.execute('CREATE DATABASE foodb')
+
+            cur.execute('SELECT pg_current_wal_insert_lsn()')
+            lsn = cur.fetchone()[0]
+
+    # Create a branch
+    env.zenith_cli(["branch", "test_createdb2", "test_createdb@" + lsn])
+
+    pg2 = env.postgres.create_start('test_createdb2')
+
+    # Test that you can connect to the new database on both branches
+    for db in (pg, pg2):
+        db.connect(dbname='foodb').close()
+
+
+#
+# Test DROP DATABASE
+#
+def test_dropdb(zenith_simple_env: ZenithEnv, test_output_dir):
+    env = zenith_simple_env
+    env.zenith_cli(["branch", "test_dropdb", "empty"])
+
+    pg = env.postgres.create_start('test_dropdb')
+    log.info("postgres is running on 'test_dropdb' branch")
+
+    with closing(pg.connect()) as conn:
+        with conn.cursor() as cur:
+            cur.execute('CREATE DATABASE foodb')
+
+            cur.execute('SELECT pg_current_wal_insert_lsn()')
+            lsn_before_drop = cur.fetchone()[0]
+
+            cur.execute("SELECT oid FROM pg_database WHERE datname='foodb';")
+            dboid = cur.fetchone()[0]
+
+    with closing(pg.connect()) as conn:
+        with conn.cursor() as cur:
+            cur.execute('DROP DATABASE foodb')
+
+            cur.execute('CHECKPOINT')
+
+            cur.execute('SELECT pg_current_wal_insert_lsn()')
+            lsn_after_drop = cur.fetchone()[0]
+
+    # Create two branches before and after database drop.
+    env.zenith_cli(["branch", "test_before_dropdb", "test_dropdb@" + lsn_before_drop])
+    pg_before = env.postgres.create_start('test_before_dropdb')
+
+    env.zenith_cli(["branch", "test_after_dropdb", "test_dropdb@" + lsn_after_drop])
+    pg_after = env.postgres.create_start('test_after_dropdb')
+
+    # Test that database exists on the branch before drop
+    pg_before.connect(dbname='foodb').close()
+
+    # Test that database subdir exists on the branch before drop
+    assert pg_before.pgdata_dir
+    dbpath = pathlib.Path(pg_before.pgdata_dir) / 'base' / str(dboid)
+    log.info(dbpath)
+
+    assert os.path.isdir(dbpath) == True
+
+    # Test that database subdir doesn't exist on the branch after drop
+    assert pg_after.pgdata_dir
+    dbpath = pathlib.Path(pg_after.pgdata_dir) / 'base' / str(dboid)
+    log.info(dbpath)
+
+    assert os.path.isdir(dbpath) == False
+
+    # Check that we restore the content of the datadir correctly
+    check_restored_datadir_content(test_output_dir, env, pg)

test_runner/batch_others/test_createuser.py

@@ -1,6 +1,7 @@
 from contextlib import closing
 
-from fixtures.zenith_fixtures import PostgresFactory, ZenithPageserver
+from fixtures.zenith_fixtures import ZenithEnv
+from fixtures.log_helper import log
 
 pytest_plugins = ("fixtures.zenith_fixtures")
 
@@ -8,11 +9,12 @@ pytest_plugins = ("fixtures.zenith_fixtures")
 #
 # Test CREATE USER to check shared catalog restore
 #
-def test_createuser(zenith_cli, pageserver: ZenithPageserver, postgres: PostgresFactory, pg_bin):
-    zenith_cli.run(["branch", "test_createuser", "empty"])
+def test_createuser(zenith_simple_env: ZenithEnv):
+    env = zenith_simple_env
+    env.zenith_cli(["branch", "test_createuser", "empty"])
 
-    pg = postgres.create_start('test_createuser')
-    print("postgres is running on 'test_createuser' branch")
+    pg = env.postgres.create_start('test_createuser')
+    log.info("postgres is running on 'test_createuser' branch")
 
     with closing(pg.connect()) as conn:
         with conn.cursor() as cur:
@@ -25,9 +27,9 @@ def test_createuser(zenith_cli, pageserver: ZenithPageserver, postgres: Postgres
             lsn = cur.fetchone()[0]
 
     # Create a branch
-    zenith_cli.run(["branch", "test_createuser2", "test_createuser@" + lsn])
+    env.zenith_cli(["branch", "test_createuser2", "test_createuser@" + lsn])
 
-    pg2 = postgres.create_start('test_createuser2')
+    pg2 = env.postgres.create_start('test_createuser2')
 
     # Test that you can connect to new branch as a new user
     assert pg2.safe_psql('select current_user', username='testuser') == [('testuser', )]