Use bounds() function

We have one pretty serious MVCC visibility bug with hot standby
replicas. We incorrectly treat any transactions that are in progress
in the primary, when the standby is started, as aborted. That can
break MVCC for queries running concurrently in the standby. It can
also lead to hint bits being set incorrectly, and that damage can last
until the replica is restarted.

The fundamental bug was that we treated any replica start as starting
from a shut down server. The fix for that is straightforward: we need
to set 'wasShutdown = false' in InitWalRecovery() (see changes in the
postgres repo).

However, that introduces a new problem: with wasShutdown = false, the
standby will not open up for queries until it receives a running-xacts
WAL record from the primary. That's correct, and that's how Postgres
hot standby always works. But it's a problem for Neon, because:

* It changes the historical behavior for existing users. Currently,
  the standby immediately opens up for queries, so if they now need to
  wait, we can breka existing use cases that were working fine
  (assuming you don't hit the MVCC issues).

* The problem is much worse for Neon than it is for standalone
  PostgreSQL, because in Neon, we can start a replica from an
  arbitrary LSN. In standalone PostgreSQL, the replica always starts
  WAL replay from a checkpoint record, and the primary arranges things
  so that there is always a running-xacts record soon after each
  checkpoint record. You can still hit this issue with PostgreSQL if
  you have a transaction with lots of subtransactions running in the
  primary, but it's pretty rare in practice.

To mitigate that, we introduce another way to collect the
running-xacts information at startup, without waiting for the
running-xacts WAL record: We can the CLOG for XIDs that haven't been
marked as committed or aborted. It has limitations with
subtransactions too, but should mitigate the problem for most users.

See https://github.com/neondatabase/neon/issues/7236.

Co-authored-by: Konstantin Knizhnik <knizhnik@neon.tech>

.github/actions/allure-report-generate/action.yml

@@ -183,7 +183,7 @@ runs:
       uses: actions/cache@v4
       with:
         path: ~/.cache/pypoetry/virtualenvs
-        key: v2-${{ runner.os }}-python-deps-${{ hashFiles('poetry.lock') }}
+        key: v2-${{ runner.os }}-${{ runner.arch }}-python-deps-${{ hashFiles('poetry.lock') }}
 
     - name: Store Allure test stat in the DB (new)
       if: ${{ !cancelled() && inputs.store-test-results-into-db == 'true' }}

.github/actions/download/action.yml

@@ -26,7 +26,7 @@ runs:
         TARGET: ${{ inputs.path }}
         ARCHIVE: /tmp/downloads/${{ inputs.name }}.tar.zst
         SKIP_IF_DOES_NOT_EXIST: ${{ inputs.skip-if-does-not-exist }}
-        PREFIX: artifacts/${{ inputs.prefix || format('{0}/{1}', github.run_id, github.run_attempt) }}
+        PREFIX: artifacts/${{ inputs.prefix || format('{0}/{1}/{2}', github.event.pull_request.head.sha || github.sha, github.run_id, github.run_attempt) }}
       run: |
         BUCKET=neon-github-public-dev
         FILENAME=$(basename $ARCHIVE)

.github/actions/run-python-test-set/action.yml

@@ -56,14 +56,14 @@ runs:
       if: inputs.build_type != 'remote'
       uses: ./.github/actions/download
       with:
-        name: neon-${{ runner.os }}-${{ inputs.build_type }}-artifact
+        name: neon-${{ runner.os }}-${{ runner.arch }}-${{ inputs.build_type }}-artifact
         path: /tmp/neon
 
     - name: Download Neon binaries for the previous release
       if: inputs.build_type != 'remote'
       uses: ./.github/actions/download
       with:
-        name: neon-${{ runner.os }}-${{ inputs.build_type }}-artifact
+        name: neon-${{ runner.os }}-${{ runner.arch }}-${{ inputs.build_type }}-artifact
         path: /tmp/neon-previous
         prefix: latest
 
@@ -89,7 +89,7 @@ runs:
       uses: actions/cache@v4
       with:
         path: ~/.cache/pypoetry/virtualenvs
-        key: v2-${{ runner.os }}-python-deps-${{ hashFiles('poetry.lock') }}
+        key: v2-${{ runner.os }}-${{ runner.arch }}-python-deps-${{ hashFiles('poetry.lock') }}
 
     - name: Install Python deps
       shell: bash -euxo pipefail {0}

.github/actions/upload/action.yml

@@ -8,7 +8,7 @@ inputs:
     description: "A directory or file to upload"
     required: true
   prefix:
-    description: "S3 prefix. Default is '${GITHUB_RUN_ID}/${GITHUB_RUN_ATTEMPT}'"
+    description: "S3 prefix. Default is '${GITHUB_SHA}/${GITHUB_RUN_ID}/${GITHUB_RUN_ATTEMPT}'"
     required: false
 
 runs:
@@ -45,7 +45,7 @@ runs:
       env:
         SOURCE: ${{ inputs.path }}
         ARCHIVE: /tmp/uploads/${{ inputs.name }}.tar.zst
-        PREFIX: artifacts/${{ inputs.prefix || format('{0}/{1}', github.run_id, github.run_attempt) }}
+        PREFIX: artifacts/${{ inputs.prefix || format('{0}/{1}/{2}', github.event.pull_request.head.sha || github.sha, github.run_id , github.run_attempt) }}
       run: |
         BUCKET=neon-github-public-dev
         FILENAME=$(basename $ARCHIVE)

.github/workflows/benchmarking.yml

@@ -77,7 +77,7 @@ jobs:
     - name: Download Neon artifact
       uses: ./.github/actions/download
       with:
-        name: neon-${{ runner.os }}-release-artifact
+        name: neon-${{ runner.os }}-${{ runner.arch }}-release-artifact
         path: /tmp/neon/
         prefix: latest
 
@@ -235,7 +235,7 @@ jobs:
     - name: Download Neon artifact
       uses: ./.github/actions/download
       with:
-        name: neon-${{ runner.os }}-release-artifact
+        name: neon-${{ runner.os }}-${{ runner.arch }}-release-artifact
         path: /tmp/neon/
         prefix: latest
 
@@ -373,7 +373,7 @@ jobs:
     - name: Download Neon artifact
       uses: ./.github/actions/download
       with:
-        name: neon-${{ runner.os }}-release-artifact
+        name: neon-${{ runner.os }}-${{ runner.arch }}-release-artifact
         path: /tmp/neon/
         prefix: latest
 
@@ -473,7 +473,7 @@ jobs:
     - name: Download Neon artifact
       uses: ./.github/actions/download
       with:
-        name: neon-${{ runner.os }}-release-artifact
+        name: neon-${{ runner.os }}-${{ runner.arch }}-release-artifact
         path: /tmp/neon/
         prefix: latest
 
@@ -576,7 +576,7 @@ jobs:
     - name: Download Neon artifact
       uses: ./.github/actions/download
       with:
-        name: neon-${{ runner.os }}-release-artifact
+        name: neon-${{ runner.os }}-${{ runner.arch }}-release-artifact
         path: /tmp/neon/
         prefix: latest
 
@@ -677,7 +677,7 @@ jobs:
     - name: Download Neon artifact
       uses: ./.github/actions/download
       with:
-        name: neon-${{ runner.os }}-release-artifact
+        name: neon-${{ runner.os }}-${{ runner.arch }}-release-artifact
         path: /tmp/neon/
         prefix: latest
 

.github/workflows/build-build-tools-image.yml

@@ -78,7 +78,7 @@ jobs:
           pull: true
           file: Dockerfile.build-tools
           cache-from: type=registry,ref=neondatabase/build-tools:cache-${{ matrix.arch }}
-          cache-to: type=registry,ref=neondatabase/build-tools:cache-${{ matrix.arch }},mode=max
+          cache-to: ${{ github.ref_name == 'main' && format('type=registry,ref=neondatabase/build-tools:cache-{0},mode=max', matrix.arch) || '' }}
           tags: neondatabase/build-tools:${{ inputs.image-tag }}-${{ matrix.arch }}
 
       - name: Remove custom docker config directory

.github/workflows/build_and_test.yml

@@ -109,7 +109,7 @@ jobs:
         uses: actions/cache@v4
         with:
           path: ~/.cache/pypoetry/virtualenvs
-          key: v2-${{ runner.os }}-python-deps-${{ hashFiles('poetry.lock') }}
+          key: v2-${{ runner.os }}-${{ runner.arch }}-python-deps-${{ hashFiles('poetry.lock') }}
 
       - name: Install Python deps
         run: ./scripts/pysync
@@ -149,7 +149,7 @@ jobs:
 #            !~/.cargo/registry/src
 #            ~/.cargo/git/
 #            target/
-#          key: v1-${{ runner.os }}-cargo-clippy-${{ hashFiles('rust-toolchain.toml') }}-${{ hashFiles('Cargo.lock') }}
+#          key: v1-${{ runner.os }}-${{ runner.arch }}-cargo-clippy-${{ hashFiles('rust-toolchain.toml') }}-${{ hashFiles('Cargo.lock') }}
 
       # Some of our rust modules use FFI and need those to be checked
       - name: Get postgres headers
@@ -291,29 +291,29 @@ jobs:
 #            target/
 #          # Fall back to older versions of the key, if no cache for current Cargo.lock was found
 #          key: |
-#            v1-${{ runner.os }}-${{ matrix.build_type }}-cargo-${{ hashFiles('rust-toolchain.toml') }}-${{ hashFiles('Cargo.lock') }}
-#            v1-${{ runner.os }}-${{ matrix.build_type }}-cargo-${{ hashFiles('rust-toolchain.toml') }}-
+#            v1-${{ runner.os }}-${{ runner.arch }}-${{ matrix.build_type }}-cargo-${{ hashFiles('rust-toolchain.toml') }}-${{ hashFiles('Cargo.lock') }}
+#            v1-${{ runner.os }}-${{ runner.arch }}-${{ matrix.build_type }}-cargo-${{ hashFiles('rust-toolchain.toml') }}-
 
       - name: Cache postgres v14 build
         id: cache_pg_14
         uses: actions/cache@v4
         with:
           path: pg_install/v14
-          key: v1-${{ runner.os }}-${{ matrix.build_type }}-pg-${{ steps.pg_v14_rev.outputs.pg_rev }}-${{ hashFiles('Makefile', 'Dockerfile.build-tools') }}
+          key: v1-${{ runner.os }}-${{ runner.arch }}-${{ matrix.build_type }}-pg-${{ steps.pg_v14_rev.outputs.pg_rev }}-${{ hashFiles('Makefile', 'Dockerfile.build-tools') }}
 
       - name: Cache postgres v15 build
         id: cache_pg_15
         uses: actions/cache@v4
         with:
           path: pg_install/v15
-          key: v1-${{ runner.os }}-${{ matrix.build_type }}-pg-${{ steps.pg_v15_rev.outputs.pg_rev }}-${{ hashFiles('Makefile', 'Dockerfile.build-tools') }}
+          key: v1-${{ runner.os }}-${{ runner.arch }}-${{ matrix.build_type }}-pg-${{ steps.pg_v15_rev.outputs.pg_rev }}-${{ hashFiles('Makefile', 'Dockerfile.build-tools') }}
 
       - name: Cache postgres v16 build
         id: cache_pg_16
         uses: actions/cache@v4
         with:
           path: pg_install/v16
-          key: v1-${{ runner.os }}-${{ matrix.build_type }}-pg-${{ steps.pg_v16_rev.outputs.pg_rev }}-${{ hashFiles('Makefile', 'Dockerfile.build-tools') }}
+          key: v1-${{ runner.os }}-${{ runner.arch }}-${{ matrix.build_type }}-pg-${{ steps.pg_v16_rev.outputs.pg_rev }}-${{ hashFiles('Makefile', 'Dockerfile.build-tools') }}
 
       - name: Build postgres v14
         if: steps.cache_pg_14.outputs.cache-hit != 'true'
@@ -411,7 +411,7 @@ jobs:
       - name: Upload Neon artifact
         uses: ./.github/actions/upload
         with:
-          name: neon-${{ runner.os }}-${{ matrix.build_type }}-artifact
+          name: neon-${{ runner.os }}-${{ runner.arch }}-${{ matrix.build_type }}-artifact
           path: /tmp/neon
 
       # XXX: keep this after the binaries.list is formed, so the coverage can properly work later
@@ -490,7 +490,7 @@ jobs:
         uses: actions/cache@v4
         with:
           path: ~/.cache/pypoetry/virtualenvs
-          key: v1-${{ runner.os }}-python-deps-${{ hashFiles('poetry.lock') }}
+          key: v1-${{ runner.os }}-${{ runner.arch }}-python-deps-${{ hashFiles('poetry.lock') }}
 
       - name: Install Python deps
         run: ./scripts/pysync
@@ -639,7 +639,7 @@ jobs:
       - name: Get Neon artifact
         uses: ./.github/actions/download
         with:
-          name: neon-${{ runner.os }}-${{ matrix.build_type }}-artifact
+          name: neon-${{ runner.os }}-${{ runner.arch }}-${{ matrix.build_type }}-artifact
           path: /tmp/neon
 
       - name: Get coverage artifact
@@ -763,7 +763,7 @@ jobs:
           pull: true
           file: Dockerfile
           cache-from: type=registry,ref=neondatabase/neon:cache-${{ matrix.arch }}
-          cache-to: type=registry,ref=neondatabase/neon:cache-${{ matrix.arch }},mode=max
+          cache-to: ${{ github.ref_name == 'main' && format('type=registry,ref=neondatabase/neon:cache-{0},mode=max', matrix.arch) || '' }}
           tags: |
             neondatabase/neon:${{ needs.tag.outputs.build-tag }}-${{ matrix.arch }}
 
@@ -855,7 +855,7 @@ jobs:
           pull: true
           file: Dockerfile.compute-node
           cache-from: type=registry,ref=neondatabase/compute-node-${{ matrix.version }}:cache-${{ matrix.arch }}
-          cache-to: type=registry,ref=neondatabase/compute-node-${{ matrix.version }}:cache-${{ matrix.arch }},mode=max
+          cache-to: ${{ github.ref_name == 'main' && format('type=registry,ref=neondatabase/compute-node-{0}:cache-{1},mode=max', matrix.version, matrix.arch) || '' }}
           tags: |
             neondatabase/compute-node-${{ matrix.version }}:${{ needs.tag.outputs.build-tag }}-${{ matrix.arch }}
 
@@ -875,7 +875,7 @@ jobs:
           file: Dockerfile.compute-node
           target: neon-pg-ext-test
           cache-from: type=registry,ref=neondatabase/neon-test-extensions-${{ matrix.version }}:cache-${{ matrix.arch }}
-          cache-to: type=registry,ref=neondatabase/neon-test-extensions-${{ matrix.version }}:cache-${{ matrix.arch }},mode=max
+          cache-to: ${{ github.ref_name == 'main' && format('type=registry,ref=neondatabase/neon-test-extensions-{0}:cache-{1},mode=max', matrix.version, matrix.arch) || '' }}
           tags: |
             neondatabase/neon-test-extensions-${{ matrix.version }}:${{needs.tag.outputs.build-tag}}-${{ matrix.arch }}
 
@@ -1245,6 +1245,7 @@ jobs:
         run: |
           if [[ "$GITHUB_REF_NAME" == "main" ]]; then
             gh workflow --repo neondatabase/aws run deploy-dev.yml --ref main -f branch=main -f dockerTag=${{needs.tag.outputs.build-tag}} -f deployPreprodRegion=false
+            gh workflow --repo neondatabase/azure run deploy.yml -f dockerTag=${{needs.tag.outputs.build-tag}}
           elif [[ "$GITHUB_REF_NAME" == "release" ]]; then
             gh workflow --repo neondatabase/aws run deploy-dev.yml --ref main \
               -f deployPgSniRouter=false \
@@ -1339,7 +1340,7 @@ jobs:
           # Update Neon artifact for the release (reuse already uploaded artifact)
           for build_type in debug release; do
             OLD_PREFIX=artifacts/${GITHUB_RUN_ID}
-            FILENAME=neon-${{ runner.os }}-${build_type}-artifact.tar.zst
+            FILENAME=neon-${{ runner.os }}-${{ runner.arch }}-${build_type}-artifact.tar.zst
 
             S3_KEY=$(aws s3api list-objects-v2 --bucket ${BUCKET} --prefix ${OLD_PREFIX} | jq -r '.Contents[]?.Key' | grep ${FILENAME} | sort --version-sort | tail -1 || true)
             if [ -z "${S3_KEY}" ]; then

.github/workflows/pg_clients.yml

@@ -41,7 +41,7 @@ jobs:
       uses: actions/cache@v4
       with:
         path: ~/.cache/pypoetry/virtualenvs
-        key: v2-${{ runner.os }}-python-deps-ubunutu-latest-${{ hashFiles('poetry.lock') }}
+        key: v2-${{ runner.os }}-${{ runner.arch }}-python-deps-ubunutu-latest-${{ hashFiles('poetry.lock') }}
 
     - name: Install Python deps
       shell: bash -euxo pipefail {0}
@@ -85,7 +85,7 @@ jobs:
       uses: actions/upload-artifact@v4
       with:
         retention-days: 7
-        name: python-test-pg_clients-${{ runner.os }}-stage-logs
+        name: python-test-pg_clients-${{ runner.os }}-${{ runner.arch }}-stage-logs
         path: ${{ env.TEST_OUTPUT }}
 
     - name: Post to a Slack channel

.neon_clippy_args

@@ -1,4 +1,5 @@
 # * `-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)
-export CLIPPY_COMMON_ARGS="--locked --workspace --all-targets -- -A unknown_lints -D warnings"
+# * `-D clippy::todo`  - don't let `todo!()` slip into `main`
+export CLIPPY_COMMON_ARGS="--locked --workspace --all-targets -- -A unknown_lints -D warnings -D clippy::todo"

Cargo.lock

@@ -1014,6 +1014,9 @@ name = "camino"
 version = "1.1.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c59e92b5a388f549b863a7bea62612c09f24c8393560709a54558a9abdfb3b9c"
+dependencies = [
+ "serde",
+]
 
 [[package]]
 name = "camino-tempfile"
@@ -1243,7 +1246,7 @@ dependencies = [
  "tokio-postgres",
  "tokio-stream",
  "tokio-util",
- "toml_edit",
+ "toml_edit 0.19.10",
  "tracing",
  "tracing-opentelemetry",
  "tracing-subscriber",
@@ -1359,8 +1362,8 @@ dependencies = [
  "tokio",
  "tokio-postgres",
  "tokio-util",
- "toml",
- "toml_edit",
+ "toml 0.7.4",
+ "toml_edit 0.19.10",
  "tracing",
  "url",
  "utils",
@@ -1666,9 +1669,9 @@ dependencies = [
 
 [[package]]
 name = "diesel"
-version = "2.1.4"
+version = "2.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "62c6fcf842f17f8c78ecf7c81d75c5ce84436b41ee07e03f490fbb5f5a8731d8"
+checksum = "62d6dcd069e7b5fe49a302411f759d4cf1cf2c27fe798ef46fb8baefc053dd2b"
 dependencies = [
  "bitflags 2.4.1",
  "byteorder",
@@ -1681,11 +1684,12 @@ dependencies = [
 
 [[package]]
 name = "diesel_derives"
-version = "2.1.2"
+version = "2.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ef8337737574f55a468005a83499da720f20c65586241ffea339db9ecdfd2b44"
+checksum = "59de76a222c2b8059f789cbe07afbfd8deb8c31dd0bc2a21f85e256c1def8259"
 dependencies = [
  "diesel_table_macro_syntax",
+ "dsl_auto_type",
  "proc-macro2",
  "quote",
  "syn 2.0.52",
@@ -1693,9 +1697,9 @@ dependencies = [
 
 [[package]]
 name = "diesel_migrations"
-version = "2.1.0"
+version = "2.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6036b3f0120c5961381b570ee20a02432d7e2d27ea60de9578799cf9156914ac"
+checksum = "8a73ce704bad4231f001bff3314d91dce4aba0770cee8b233991859abc15c1f6"
 dependencies = [
  "diesel",
  "migrations_internals",
@@ -1704,9 +1708,9 @@ dependencies = [
 
 [[package]]
 name = "diesel_table_macro_syntax"
-version = "0.1.0"
+version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fc5557efc453706fed5e4fa85006fe9817c224c3f480a34c7e5959fd700921c5"
+checksum = "209c735641a413bc68c4923a9d6ad4bcb3ca306b794edaa7eb0b3228a99ffb25"
 dependencies = [
  "syn 2.0.52",
 ]
@@ -1742,6 +1746,20 @@ dependencies = [
  "const-random",
 ]
 
+[[package]]
+name = "dsl_auto_type"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0892a17df262a24294c382f0d5997571006e7a4348b4327557c4ff1cd4a8bccc"
+dependencies = [
+ "darling",
+ "either",
+ "heck 0.5.0",
+ "proc-macro2",
+ "quote",
+ "syn 2.0.52",
+]
+
 [[package]]
 name = "dyn-clone"
 version = "1.0.14"
@@ -3081,19 +3099,19 @@ dependencies = [
 
 [[package]]
 name = "migrations_internals"
-version = "2.1.0"
+version = "2.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0f23f71580015254b020e856feac3df5878c2c7a8812297edd6c0a485ac9dada"
+checksum = "fd01039851e82f8799046eabbb354056283fb265c8ec0996af940f4e85a380ff"
 dependencies = [
  "serde",
- "toml",
+ "toml 0.8.14",
 ]
 
 [[package]]
 name = "migrations_macros"
-version = "2.1.0"
+version = "2.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cce3325ac70e67bbab5bd837a31cae01f1a6db64e0e744a33cb03a543469ef08"
+checksum = "ffb161cc72176cb37aa47f1fc520d3ef02263d67d661f44f05d05a079e1237fd"
 dependencies = [
  "migrations_internals",
  "proc-macro2",
@@ -3573,7 +3591,7 @@ dependencies = [
  "thiserror",
  "tokio",
  "tokio-util",
- "toml_edit",
+ "toml_edit 0.19.10",
  "utils",
  "workspace_hack",
 ]
@@ -3656,7 +3674,7 @@ dependencies = [
  "tokio-stream",
  "tokio-tar",
  "tokio-util",
- "toml_edit",
+ "toml_edit 0.19.10",
  "tracing",
  "twox-hash",
  "url",
@@ -4002,7 +4020,7 @@ dependencies = [
 [[package]]
 name = "postgres"
 version = "0.19.4"
-source = "git+https://github.com/neondatabase/rust-postgres.git?branch=neon#20031d7a9ee1addeae6e0968e3899ae6bf01cee2"
+source = "git+https://github.com/neondatabase/rust-postgres.git?branch=neon#cff6927e4f58b1af6ecc2ee7279df1f2ff537295"
 dependencies = [
  "bytes",
  "fallible-iterator",
@@ -4015,7 +4033,7 @@ dependencies = [
 [[package]]
 name = "postgres-protocol"
 version = "0.6.4"
-source = "git+https://github.com/neondatabase/rust-postgres.git?branch=neon#20031d7a9ee1addeae6e0968e3899ae6bf01cee2"
+source = "git+https://github.com/neondatabase/rust-postgres.git?branch=neon#cff6927e4f58b1af6ecc2ee7279df1f2ff537295"
 dependencies = [
  "base64 0.20.0",
  "byteorder",
@@ -4034,7 +4052,7 @@ dependencies = [
 [[package]]
 name = "postgres-types"
 version = "0.2.4"
-source = "git+https://github.com/neondatabase/rust-postgres.git?branch=neon#20031d7a9ee1addeae6e0968e3899ae6bf01cee2"
+source = "git+https://github.com/neondatabase/rust-postgres.git?branch=neon#cff6927e4f58b1af6ecc2ee7279df1f2ff537295"
 dependencies = [
  "bytes",
  "fallible-iterator",
@@ -4647,6 +4665,7 @@ dependencies = [
  "futures-util",
  "http-types",
  "humantime",
+ "humantime-serde",
  "hyper 0.14.26",
  "itertools",
  "metrics",
@@ -4661,7 +4680,7 @@ dependencies = [
  "tokio",
  "tokio-stream",
  "tokio-util",
- "toml_edit",
+ "toml_edit 0.19.10",
  "tracing",
  "utils",
  "workspace_hack",
@@ -5160,7 +5179,7 @@ dependencies = [
  "tokio-stream",
  "tokio-tar",
  "tokio-util",
- "toml_edit",
+ "toml_edit 0.19.10",
  "tracing",
  "tracing-subscriber",
  "url",
@@ -5439,9 +5458,9 @@ dependencies = [
 
 [[package]]
 name = "serde_spanned"
-version = "0.6.2"
+version = "0.6.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "93107647184f6027e3b7dcb2e11034cf95ffa1e3a682c67951963ac69c1c007d"
+checksum = "79e674e01f999af37c49f70a6ede167a8a60b2503e56c5599532a65baa5969a0"
 dependencies = [
  "serde",
 ]
@@ -6206,7 +6225,7 @@ dependencies = [
 [[package]]
 name = "tokio-postgres"
 version = "0.7.7"
-source = "git+https://github.com/neondatabase/rust-postgres.git?branch=neon#20031d7a9ee1addeae6e0968e3899ae6bf01cee2"
+source = "git+https://github.com/neondatabase/rust-postgres.git?branch=neon#cff6927e4f58b1af6ecc2ee7279df1f2ff537295"
 dependencies = [
  "async-trait",
  "byteorder",
@@ -6326,14 +6345,26 @@ dependencies = [
  "serde",
  "serde_spanned",
  "toml_datetime",
- "toml_edit",
+ "toml_edit 0.19.10",
+]
+
+[[package]]
+name = "toml"
+version = "0.8.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6f49eb2ab21d2f26bd6db7bf383edc527a7ebaee412d17af4d40fdccd442f335"
+dependencies = [
+ "serde",
+ "serde_spanned",
+ "toml_datetime",
+ "toml_edit 0.22.14",
 ]
 
 [[package]]
 name = "toml_datetime"
-version = "0.6.2"
+version = "0.6.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5a76a9312f5ba4c2dec6b9161fdf25d87ad8a09256ccea5a556fef03c706a10f"
+checksum = "4badfd56924ae69bcc9039335b2e017639ce3f9b001c393c1b2d1ef846ce2cbf"
 dependencies = [
  "serde",
 ]
@@ -6348,7 +6379,20 @@ dependencies = [
  "serde",
  "serde_spanned",
  "toml_datetime",
- "winnow",
+ "winnow 0.4.6",
+]
+
+[[package]]
+name = "toml_edit"
+version = "0.22.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f21c7aaf97f1bd9ca9d4f9e73b0a6c74bd5afef56f2bc931943a6e1c37e04e38"
+dependencies = [
+ "indexmap 2.0.1",
+ "serde",
+ "serde_spanned",
+ "toml_datetime",
+ "winnow 0.6.13",
 ]
 
 [[package]]
@@ -7331,6 +7375,15 @@ dependencies = [
  "memchr",
 ]
 
+[[package]]
+name = "winnow"
+version = "0.6.13"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "59b5e5f6c299a3c7890b876a2a587f3115162487e704907d9b6cd29473052ba1"
+dependencies = [
+ "memchr",
+]
+
 [[package]]
 name = "winreg"
 version = "0.50.0"
@@ -7367,6 +7420,7 @@ dependencies = [
  "base64 0.21.1",
  "base64ct",
  "bytes",
+ "camino",
  "cc",
  "chrono",
  "clap",
@@ -7419,7 +7473,7 @@ dependencies = [
  "tokio-rustls 0.24.0",
  "tokio-util",
  "toml_datetime",
- "toml_edit",
+ "toml_edit 0.19.10",
  "tonic",
  "tower",
  "tracing",

Dockerfile.build-tools

@@ -73,13 +73,6 @@ RUN curl -fsSL 'https://apt.llvm.org/llvm-snapshot.gpg.key' | apt-key add - \
     && bash -c 'for f in /usr/bin/clang*-${LLVM_VERSION} /usr/bin/llvm*-${LLVM_VERSION}; do ln -s "${f}" "${f%-${LLVM_VERSION}}"; done' \
     && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
 
-# PostgreSQL 14
-RUN curl -fsSL 'https://www.postgresql.org/media/keys/ACCC4CF8.asc' | apt-key add - \
-    && echo 'deb http://apt.postgresql.org/pub/repos/apt bullseye-pgdg main' > /etc/apt/sources.list.d/pgdg.list \
-    && apt update \
-    && apt install -y postgresql-client-14 \
-    && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
-
 # AWS CLI
 RUN curl "https://awscli.amazonaws.com/awscli-exe-linux-$(uname -m).zip" -o "awscliv2.zip" \
     && unzip -q awscliv2.zip \
@@ -113,10 +106,10 @@ RUN for package in Capture::Tiny DateTime Devel::Cover Digest::MD5 File::Spec JS
     && rm -rf ../lcov.tar.gz
 
 # Compile and install the static OpenSSL library
-ENV OPENSSL_VERSION=3.2.2
+ENV OPENSSL_VERSION=1.1.1w
 ENV OPENSSL_PREFIX=/usr/local/openssl
 RUN wget -O /tmp/openssl-${OPENSSL_VERSION}.tar.gz https://www.openssl.org/source/openssl-${OPENSSL_VERSION}.tar.gz && \
-    echo "197149c18d9e9f292c43f0400acaba12e5f52cacfe050f3d199277ea738ec2e7 /tmp/openssl-${OPENSSL_VERSION}.tar.gz" | sha256sum --check && \
+    echo "cf3098950cb4d853ad95c0841f1f9c6d3dc102dccfcacd521d93925208b76ac8 /tmp/openssl-${OPENSSL_VERSION}.tar.gz" | sha256sum --check && \
     cd /tmp && \
     tar xzvf /tmp/openssl-${OPENSSL_VERSION}.tar.gz && \
     rm /tmp/openssl-${OPENSSL_VERSION}.tar.gz && \

Dockerfile.compute-node

@@ -467,31 +467,6 @@ RUN case "${PG_VERSION}" in \
     make install -j $(getconf _NPROCESSORS_ONLN) && \
     echo "trusted = true" >> /usr/local/pgsql/share/extension/pg_hint_plan.control
 
-#########################################################################################
-#
-# Layer "kq-imcx-pg-build"
-# compile kq_imcx extension
-#
-#########################################################################################
-FROM build-deps AS kq-imcx-pg-build
-COPY --from=pg-build /usr/local/pgsql/ /usr/local/pgsql/
-
-ENV PATH "/usr/local/pgsql/bin/:$PATH"
-RUN apt-get update && \
-    apt-get install -y git libgtk2.0-dev libpq-dev libpam-dev libxslt-dev libkrb5-dev cmake && \
-    wget https://github.com/ketteq-neon/postgres-exts/archive/e0bd1a9d9313d7120c1b9c7bb15c48c0dede4c4e.tar.gz -O kq_imcx.tar.gz && \
-    echo "dc93a97ff32d152d32737ba7e196d9687041cda15e58ab31344c2f2de8855336 kq_imcx.tar.gz" | sha256sum --check && \
-    mkdir kq_imcx-src && cd kq_imcx-src && tar xzf ../kq_imcx.tar.gz --strip-components=1 -C . && \
-    find /usr/local/pgsql -type f | sed 's|^/usr/local/pgsql/||' > /before.txt &&\
-    mkdir build && cd build && \
-    cmake -DCMAKE_BUILD_TYPE=Release .. && \
-    make -j $(getconf _NPROCESSORS_ONLN) && \
-    make -j $(getconf _NPROCESSORS_ONLN) install && \
-    echo 'trusted = true' >> /usr/local/pgsql/share/extension/kq_imcx.control && \
-    find /usr/local/pgsql -type f | sed 's|^/usr/local/pgsql/||' > /after.txt &&\
-    mkdir -p /extensions/kq_imcx && cp /usr/local/pgsql/share/extension/kq_imcx.control /extensions/kq_imcx && \
-    sort -o /before.txt /before.txt && sort -o /after.txt /after.txt && \
-    comm -13 /before.txt /after.txt | tar --directory=/usr/local/pgsql --zstd -cf /extensions/kq_imcx.tar.zst -T -
 
 #########################################################################################
 #
@@ -840,7 +815,6 @@ COPY --from=hll-pg-build /usr/local/pgsql/ /usr/local/pgsql/
 COPY --from=plpgsql-check-pg-build /usr/local/pgsql/ /usr/local/pgsql/
 COPY --from=timescaledb-pg-build /usr/local/pgsql/ /usr/local/pgsql/
 COPY --from=pg-hint-plan-pg-build /usr/local/pgsql/ /usr/local/pgsql/
-COPY --from=kq-imcx-pg-build /usr/local/pgsql/ /usr/local/pgsql/
 COPY --from=pg-cron-pg-build /usr/local/pgsql/ /usr/local/pgsql/
 COPY --from=pg-pgx-ulid-build /usr/local/pgsql/ /usr/local/pgsql/
 COPY --from=rdkit-pg-build /usr/local/pgsql/ /usr/local/pgsql/
@@ -961,7 +935,6 @@ COPY --from=plpgsql-check-pg-build /plpgsql_check.tar.gz /ext-src
 #COPY --from=timescaledb-pg-build /timescaledb.tar.gz /ext-src
 COPY --from=pg-hint-plan-pg-build /pg_hint_plan.tar.gz /ext-src
 COPY patches/pg_hintplan.patch /ext-src
-#COPY --from=kq-imcx-pg-build /kq_imcx.tar.gz /ext-src
 COPY --from=pg-cron-pg-build /pg_cron.tar.gz /ext-src
 COPY patches/pg_cron.patch /ext-src
 #COPY --from=pg-pgx-ulid-build /home/nonroot/pgx_ulid.tar.gz /ext-src

compute_tools/src/config.rs

@@ -83,12 +83,6 @@ pub fn write_postgres_conf(
         ComputeMode::Replica => {
             // hot_standby is 'on' by default, but let's be explicit
             writeln!(file, "hot_standby=on")?;
-
-            // Inform the replica about the primary state
-            // Default is 'false'
-            if let Some(primary_is_running) = spec.primary_is_running {
-                writeln!(file, "neon.primary_is_running={}", primary_is_running)?;
-            }
         }
     }
 

compute_tools/src/monitor.rs

@@ -17,7 +17,11 @@ const MONITOR_CHECK_INTERVAL: Duration = Duration::from_millis(500);
 // should be handled gracefully.
 fn watch_compute_activity(compute: &ComputeNode) {
     // Suppose that `connstr` doesn't change
-    let connstr = compute.connstr.as_str();
+    let mut connstr = compute.connstr.clone();
+    connstr
+        .query_pairs_mut()
+        .append_pair("application_name", "compute_activity_monitor");
+    let connstr = connstr.as_str();
 
     // During startup and configuration we connect to every Postgres database,
     // but we don't want to count this as some user activity. So wait until

control_plane/src/bin/neon_local.rs

@@ -21,10 +21,8 @@ use pageserver_api::config::{
     DEFAULT_HTTP_LISTEN_PORT as DEFAULT_PAGESERVER_HTTP_PORT,
     DEFAULT_PG_LISTEN_PORT as DEFAULT_PAGESERVER_PG_PORT,
 };
-use pageserver_api::controller_api::PlacementPolicy;
-use pageserver_api::models::{
-    ShardParameters, TenantCreateRequest, TimelineCreateRequest, TimelineInfo,
-};
+use pageserver_api::controller_api::{PlacementPolicy, TenantCreateRequest};
+use pageserver_api::models::{ShardParameters, TimelineCreateRequest, TimelineInfo};
 use pageserver_api::shard::{ShardCount, ShardStripeSize, TenantShardId};
 use postgres_backend::AuthType;
 use postgres_connection::parse_host_port;
@@ -600,13 +598,9 @@ async fn handle_timeline(timeline_match: &ArgMatches, env: &mut local_env::Local
         Some(("import", import_match)) => {
             let tenant_id = get_tenant_id(import_match, env)?;
             let timeline_id = parse_timeline_id(import_match)?.expect("No timeline id provided");
-            let name = import_match
-                .get_one::<String>("node-name")
-                .ok_or_else(|| anyhow!("No node name provided"))?;
-            let update_catalog = import_match
-                .get_one::<bool>("update-catalog")
-                .cloned()
-                .unwrap_or_default();
+            let branch_name = import_match
+                .get_one::<String>("branch-name")
+                .ok_or_else(|| anyhow!("No branch name provided"))?;
 
             // Parse base inputs
             let base_tarfile = import_match
@@ -633,24 +627,11 @@ async fn handle_timeline(timeline_match: &ArgMatches, env: &mut local_env::Local
                 .copied()
                 .context("Failed to parse postgres version from the argument string")?;
 
-            let mut cplane = ComputeControlPlane::load(env.clone())?;
             println!("Importing timeline into pageserver ...");
             pageserver
                 .timeline_import(tenant_id, timeline_id, base, pg_wal, pg_version)
                 .await?;
-            env.register_branch_mapping(name.to_string(), tenant_id, timeline_id)?;
-
-            println!("Creating endpoint for imported timeline ...");
-            cplane.new_endpoint(
-                name,
-                tenant_id,
-                timeline_id,
-                None,
-                None,
-                pg_version,
-                ComputeMode::Primary,
-                !update_catalog,
-            )?;
+            env.register_branch_mapping(branch_name.to_string(), tenant_id, timeline_id)?;
             println!("Done");
         }
         Some(("branch", branch_match)) => {
@@ -865,20 +846,13 @@ async fn handle_endpoint(ep_match: &ArgMatches, env: &local_env::LocalEnv) -> Re
 
             let allow_multiple = sub_args.get_flag("allow-multiple");
 
-            // If --safekeepers argument is given, use only the listed safekeeper nodes.
-            let safekeepers =
-                if let Some(safekeepers_str) = sub_args.get_one::<String>("safekeepers") {
-                    let mut safekeepers: Vec<NodeId> = Vec::new();
-                    for sk_id in safekeepers_str.split(',').map(str::trim) {
-                        let sk_id = NodeId(u64::from_str(sk_id).map_err(|_| {
-                            anyhow!("invalid node ID \"{sk_id}\" in --safekeepers list")
-                        })?);
-                        safekeepers.push(sk_id);
-                    }
-                    safekeepers
-                } else {
-                    env.safekeepers.iter().map(|sk| sk.id).collect()
-                };
+            // If --safekeepers argument is given, use only the listed
+            // safekeeper nodes; otherwise all from the env.
+            let safekeepers = if let Some(safekeepers) = parse_safekeepers(sub_args)? {
+                safekeepers
+            } else {
+                env.safekeepers.iter().map(|sk| sk.id).collect()
+            };
 
             let endpoint = cplane
                 .endpoints
@@ -982,7 +956,10 @@ async fn handle_endpoint(ep_match: &ArgMatches, env: &local_env::LocalEnv) -> Re
                         })
                         .collect::<Vec<_>>()
                 };
-            endpoint.reconfigure(pageservers, None).await?;
+            // If --safekeepers argument is given, use only the listed
+            // safekeeper nodes; otherwise all from the env.
+            let safekeepers = parse_safekeepers(sub_args)?;
+            endpoint.reconfigure(pageservers, None, safekeepers).await?;
         }
         "stop" => {
             let endpoint_id = sub_args
@@ -1004,6 +981,23 @@ async fn handle_endpoint(ep_match: &ArgMatches, env: &local_env::LocalEnv) -> Re
     Ok(())
 }
 
+/// Parse --safekeepers as list of safekeeper ids.
+fn parse_safekeepers(sub_args: &ArgMatches) -> Result<Option<Vec<NodeId>>> {
+    if let Some(safekeepers_str) = sub_args.get_one::<String>("safekeepers") {
+        let mut safekeepers: Vec<NodeId> = Vec::new();
+        for sk_id in safekeepers_str.split(',').map(str::trim) {
+            let sk_id = NodeId(
+                u64::from_str(sk_id)
+                    .map_err(|_| anyhow!("invalid node ID \"{sk_id}\" in --safekeepers list"))?,
+            );
+            safekeepers.push(sk_id);
+        }
+        Ok(Some(safekeepers))
+    } else {
+        Ok(None)
+    }
+}
+
 fn handle_mappings(sub_match: &ArgMatches, env: &mut local_env::LocalEnv) -> Result<()> {
     let (sub_name, sub_args) = match sub_match.subcommand() {
         Some(ep_subcommand_data) => ep_subcommand_data,
@@ -1487,8 +1481,7 @@ fn cli() -> Command {
                 .about("Import timeline from basebackup directory")
                 .arg(tenant_id_arg.clone())
                 .arg(timeline_id_arg.clone())
-                .arg(Arg::new("node-name").long("node-name")
-                    .help("Name to assign to the imported timeline"))
+                .arg(branch_name_arg.clone())
                 .arg(Arg::new("base-tarfile")
                     .long("base-tarfile")
                     .value_parser(value_parser!(PathBuf))
@@ -1504,7 +1497,6 @@ fn cli() -> Command {
                 .arg(Arg::new("end-lsn").long("end-lsn")
                     .help("Lsn the basebackup ends at"))
                 .arg(pg_version_arg.clone())
-                .arg(update_catalog.clone())
             )
         ).subcommand(
             Command::new("tenant")
@@ -1609,7 +1601,7 @@ fn cli() -> Command {
                     .about("Start postgres.\n If the endpoint doesn't exist yet, it is created.")
                     .arg(endpoint_id_arg.clone())
                     .arg(endpoint_pageserver_id_arg.clone())
-                    .arg(safekeepers_arg)
+                    .arg(safekeepers_arg.clone())
                     .arg(remote_ext_config_args)
                     .arg(create_test_user)
                     .arg(allow_multiple.clone())
@@ -1618,6 +1610,7 @@ fn cli() -> Command {
                 .subcommand(Command::new("reconfigure")
                             .about("Reconfigure the endpoint")
                             .arg(endpoint_pageserver_id_arg)
+                            .arg(safekeepers_arg)
                             .arg(endpoint_id_arg.clone())
                             .arg(tenant_id_arg.clone())
                 )

control_plane/src/endpoint.rs

@@ -499,6 +499,23 @@ impl Endpoint {
             .join(",")
     }
 
+    /// Map safekeepers ids to the actual connection strings.
+    fn build_safekeepers_connstrs(&self, sk_ids: Vec<NodeId>) -> Result<Vec<String>> {
+        let mut safekeeper_connstrings = Vec::new();
+        if self.mode == ComputeMode::Primary {
+            for sk_id in sk_ids {
+                let sk = self
+                    .env
+                    .safekeepers
+                    .iter()
+                    .find(|node| node.id == sk_id)
+                    .ok_or_else(|| anyhow!("safekeeper {sk_id} does not exist"))?;
+                safekeeper_connstrings.push(format!("127.0.0.1:{}", sk.get_compute_port()));
+            }
+        }
+        Ok(safekeeper_connstrings)
+    }
+
     pub async fn start(
         &self,
         auth_token: &Option<String>,
@@ -523,18 +540,7 @@ impl Endpoint {
         let pageserver_connstring = Self::build_pageserver_connstr(&pageservers);
         assert!(!pageserver_connstring.is_empty());
 
-        let mut safekeeper_connstrings = Vec::new();
-        if self.mode == ComputeMode::Primary {
-            for sk_id in safekeepers {
-                let sk = self
-                    .env
-                    .safekeepers
-                    .iter()
-                    .find(|node| node.id == sk_id)
-                    .ok_or_else(|| anyhow!("safekeeper {sk_id} does not exist"))?;
-                safekeeper_connstrings.push(format!("127.0.0.1:{}", sk.get_compute_port()));
-            }
-        }
+        let safekeeper_connstrings = self.build_safekeepers_connstrs(safekeepers)?;
 
         // check for file remote_extensions_spec.json
         // if it is present, read it and pass to compute_ctl
@@ -592,7 +598,6 @@ impl Endpoint {
             remote_extensions,
             pgbouncer_settings: None,
             shard_stripe_size: Some(shard_stripe_size),
-            primary_is_running: None,
         };
         let spec_path = self.endpoint_path().join("spec.json");
         std::fs::write(spec_path, serde_json::to_string_pretty(&spec)?)?;
@@ -741,6 +746,7 @@ impl Endpoint {
         &self,
         mut pageservers: Vec<(Host, u16)>,
         stripe_size: Option<ShardStripeSize>,
+        safekeepers: Option<Vec<NodeId>>,
     ) -> Result<()> {
         let mut spec: ComputeSpec = {
             let spec_path = self.endpoint_path().join("spec.json");
@@ -775,6 +781,12 @@ impl Endpoint {
             spec.shard_stripe_size = stripe_size.map(|s| s.0 as usize);
         }
 
+        // If safekeepers are not specified, don't change them.
+        if let Some(safekeepers) = safekeepers {
+            let safekeeper_connstrings = self.build_safekeepers_connstrs(safekeepers)?;
+            spec.safekeeper_connstrings = safekeeper_connstrings;
+        }
+
         let client = reqwest::Client::builder()
             .timeout(Duration::from_secs(30))
             .build()

control_plane/src/pageserver.rs

@@ -17,8 +17,7 @@ use anyhow::{bail, Context};
 use camino::Utf8PathBuf;
 use futures::SinkExt;
 use pageserver_api::models::{
-    self, AuxFilePolicy, LocationConfig, ShardParameters, TenantHistorySize, TenantInfo,
-    TimelineInfo,
+    self, AuxFilePolicy, LocationConfig, TenantHistorySize, TenantInfo, TimelineInfo,
 };
 use pageserver_api::shard::TenantShardId;
 use pageserver_client::mgmt_api;
@@ -397,28 +396,6 @@ impl PageServerNode {
         }
     }
 
-    pub async fn tenant_create(
-        &self,
-        new_tenant_id: TenantId,
-        generation: Option<u32>,
-        settings: HashMap<&str, &str>,
-    ) -> anyhow::Result<TenantId> {
-        let config = Self::parse_config(settings.clone())?;
-
-        let request = models::TenantCreateRequest {
-            new_tenant_id: TenantShardId::unsharded(new_tenant_id),
-            generation,
-            config,
-            shard_parameters: ShardParameters::default(),
-            // Placement policy is not meaningful for creations not done via storage controller
-            placement_policy: None,
-        };
-        if !settings.is_empty() {
-            bail!("Unrecognized tenant settings: {settings:?}")
-        }
-        Ok(self.http_client.tenant_create(&request).await?)
-    }
-
     pub async fn tenant_config(
         &self,
         tenant_id: TenantId,

control_plane/src/storage_controller.rs

@@ -5,12 +5,11 @@ use crate::{
 use camino::{Utf8Path, Utf8PathBuf};
 use pageserver_api::{
     controller_api::{
-        NodeConfigureRequest, NodeRegisterRequest, TenantCreateResponse, TenantLocateResponse,
-        TenantShardMigrateRequest, TenantShardMigrateResponse,
+        NodeConfigureRequest, NodeRegisterRequest, TenantCreateRequest, TenantCreateResponse,
+        TenantLocateResponse, TenantShardMigrateRequest, TenantShardMigrateResponse,
     },
     models::{
-        TenantCreateRequest, TenantShardSplitRequest, TenantShardSplitResponse,
-        TimelineCreateRequest, TimelineInfo,
+        TenantShardSplitRequest, TenantShardSplitResponse, TimelineCreateRequest, TimelineInfo,
     },
     shard::{ShardStripeSize, TenantShardId},
 };

control_plane/storcon_cli/src/main.rs

@@ -1,16 +1,16 @@
 use futures::StreamExt;
-use std::{collections::HashMap, str::FromStr, time::Duration};
+use std::{str::FromStr, time::Duration};
 
 use clap::{Parser, Subcommand};
 use pageserver_api::{
     controller_api::{
-        NodeAvailabilityWrapper, NodeDescribeResponse, ShardSchedulingPolicy,
+        NodeAvailabilityWrapper, NodeDescribeResponse, ShardSchedulingPolicy, TenantCreateRequest,
         TenantDescribeResponse, TenantPolicyRequest,
     },
     models::{
         EvictionPolicy, EvictionPolicyLayerAccessThreshold, LocationConfigSecondary,
-        ShardParameters, TenantConfig, TenantConfigRequest, TenantCreateRequest,
-        TenantShardSplitRequest, TenantShardSplitResponse,
+        ShardParameters, TenantConfig, TenantConfigRequest, TenantShardSplitRequest,
+        TenantShardSplitResponse,
     },
     shard::{ShardStripeSize, TenantShardId},
 };
@@ -21,7 +21,7 @@ use utils::id::{NodeId, TenantId};
 
 use pageserver_api::controller_api::{
     NodeConfigureRequest, NodeRegisterRequest, NodeSchedulingPolicy, PlacementPolicy,
-    TenantLocateResponse, TenantShardMigrateRequest, TenantShardMigrateResponse,
+    TenantShardMigrateRequest, TenantShardMigrateResponse,
 };
 
 #[derive(Subcommand, Debug)]
@@ -110,12 +110,6 @@ enum Command {
         #[arg(long)]
         config: String,
     },
-    /// Attempt to balance the locations for a tenant across pageservers.  This is a client-side
-    /// alternative to the storage controller's scheduling optimization behavior.
-    TenantScatter {
-        #[arg(long)]
-        tenant_id: TenantId,
-    },
     /// Print details about a particular tenant, including all its shards' states.
     TenantDescribe {
         #[arg(long)]
@@ -342,14 +336,18 @@ async fn main() -> anyhow::Result<()> {
                 .await?;
         }
         Command::TenantCreate { tenant_id } => {
-            vps_client
-                .tenant_create(&TenantCreateRequest {
-                    new_tenant_id: TenantShardId::unsharded(tenant_id),
-                    generation: None,
-                    shard_parameters: ShardParameters::default(),
-                    placement_policy: Some(PlacementPolicy::Attached(1)),
-                    config: TenantConfig::default(),
-                })
+            storcon_client
+                .dispatch(
+                    Method::POST,
+                    "v1/tenant".to_string(),
+                    Some(TenantCreateRequest {
+                        new_tenant_id: TenantShardId::unsharded(tenant_id),
+                        generation: None,
+                        shard_parameters: ShardParameters::default(),
+                        placement_policy: Some(PlacementPolicy::Attached(1)),
+                        config: TenantConfig::default(),
+                    }),
+                )
                 .await?;
         }
         Command::TenantDelete { tenant_id } => {
@@ -498,88 +496,6 @@ async fn main() -> anyhow::Result<()> {
                 })
                 .await?;
         }
-        Command::TenantScatter { tenant_id } => {
-            // Find the shards
-            let locate_response = storcon_client
-                .dispatch::<(), TenantLocateResponse>(
-                    Method::GET,
-                    format!("control/v1/tenant/{tenant_id}/locate"),
-                    None,
-                )
-                .await?;
-            let shards = locate_response.shards;
-
-            let mut node_to_shards: HashMap<NodeId, Vec<TenantShardId>> = HashMap::new();
-            let shard_count = shards.len();
-            for s in shards {
-                let entry = node_to_shards.entry(s.node_id).or_default();
-                entry.push(s.shard_id);
-            }
-
-            // Load list of available nodes
-            let nodes_resp = storcon_client
-                .dispatch::<(), Vec<NodeDescribeResponse>>(
-                    Method::GET,
-                    "control/v1/node".to_string(),
-                    None,
-                )
-                .await?;
-
-            for node in nodes_resp {
-                if matches!(node.availability, NodeAvailabilityWrapper::Active) {
-                    node_to_shards.entry(node.id).or_default();
-                }
-            }
-
-            let max_shard_per_node = shard_count / node_to_shards.len();
-
-            loop {
-                let mut migrate_shard = None;
-                for shards in node_to_shards.values_mut() {
-                    if shards.len() > max_shard_per_node {
-                        // Pick the emptiest
-                        migrate_shard = Some(shards.pop().unwrap());
-                    }
-                }
-                let Some(migrate_shard) = migrate_shard else {
-                    break;
-                };
-
-                // Pick the emptiest node to migrate to
-                let mut destinations = node_to_shards
-                    .iter()
-                    .map(|(k, v)| (k, v.len()))
-                    .collect::<Vec<_>>();
-                destinations.sort_by_key(|i| i.1);
-                let (destination_node, destination_count) = *destinations.first().unwrap();
-                if destination_count + 1 > max_shard_per_node {
-                    // Even the emptiest destination doesn't have space: we're done
-                    break;
-                }
-                let destination_node = *destination_node;
-
-                node_to_shards
-                    .get_mut(&destination_node)
-                    .unwrap()
-                    .push(migrate_shard);
-
-                println!("Migrate {} -> {} ...", migrate_shard, destination_node);
-
-                storcon_client
-                    .dispatch::<TenantShardMigrateRequest, TenantShardMigrateResponse>(
-                        Method::PUT,
-                        format!("control/v1/tenant/{migrate_shard}/migrate"),
-                        Some(TenantShardMigrateRequest {
-                            tenant_shard_id: migrate_shard,
-                            node_id: destination_node,
-                        }),
-                    )
-                    .await?;
-                println!("Migrate {} -> {} OK", migrate_shard, destination_node);
-            }
-
-            // Spread the shards across the nodes
-        }
         Command::TenantDescribe { tenant_id } => {
             let describe_response = storcon_client
                 .dispatch::<(), TenantDescribeResponse>(

docker-compose/README.md

@@ -0,0 +1,10 @@
+
+# Example docker compose configuration
+
+The configuration in this directory is used for testing Neon docker images: it is
+not intended for deploying a usable system.  To run a development environment where
+you can experiment with a minature Neon system, use `cargo neon` rather than container images.
+
+This configuration does not start the storage controller, because the controller
+needs a way to reconfigure running computes, and no such thing exists in this setup.
+

docker-compose/compute_wrapper/shell/compute.sh

@@ -23,11 +23,10 @@ echo "Page server is ready."
 echo "Create a tenant and timeline"
 generate_id tenant_id
 PARAMS=(
-     -sb 
-     -X POST
+     -X PUT
      -H "Content-Type: application/json"
-     -d "{\"new_tenant_id\": \"${tenant_id}\"}"
-     http://pageserver:9898/v1/tenant/
+     -d "{\"mode\": \"AttachedSingle\", \"generation\": 1, \"tenant_conf\": {}}"
+     "http://pageserver:9898/v1/tenant/${tenant_id}/location_config"
 )
 result=$(curl "${PARAMS[@]}")
 echo $result | jq .

libs/compute_api/src/spec.rs

@@ -96,12 +96,6 @@ pub struct ComputeSpec {
     // Stripe size for pageserver sharding, in pages
     #[serde(default)]
     pub shard_stripe_size: Option<usize>,
-
-    // When we are starting a new replica in hot standby mode,
-    // we need to know if the primary is running.
-    // This is used to determine if replica should wait for
-    // RUNNING_XACTS from primary or not.
-    pub primary_is_running: Option<bool>,
 }
 
 /// Feature flag to signal `compute_ctl` to enable certain experimental functionality.

libs/metrics/src/lib.rs

@@ -103,9 +103,10 @@ static MAXRSS_KB: Lazy<IntGauge> = Lazy::new(|| {
     .expect("Failed to register maxrss_kb int gauge")
 });
 
-pub const DISK_WRITE_SECONDS_BUCKETS: &[f64] = &[
-    0.000_050, 0.000_100, 0.000_500, 0.001, 0.003, 0.005, 0.01, 0.05, 0.1, 0.3, 0.5,
-];
+/// Most common fsync latency is 50 µs - 100 µs, but it can be much higher,
+/// especially during many concurrent disk operations.
+pub const DISK_FSYNC_SECONDS_BUCKETS: &[f64] =
+    &[0.001, 0.005, 0.01, 0.05, 0.1, 0.5, 1.0, 5.0, 10.0, 30.0];
 
 pub struct BuildInfo {
     pub revision: &'static str,

libs/pageserver_api/src/controller_api.rs

@@ -11,6 +11,27 @@ use crate::{
     shard::{ShardStripeSize, TenantShardId},
 };
 
+#[derive(Serialize, Deserialize, Debug)]
+#[serde(deny_unknown_fields)]
+pub struct TenantCreateRequest {
+    pub new_tenant_id: TenantShardId,
+    #[serde(default)]
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub generation: Option<u32>,
+
+    // If omitted, create a single shard with TenantShardId::unsharded()
+    #[serde(default)]
+    #[serde(skip_serializing_if = "ShardParameters::is_unsharded")]
+    pub shard_parameters: ShardParameters,
+
+    #[serde(default)]
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub placement_policy: Option<PlacementPolicy>,
+
+    #[serde(flatten)]
+    pub config: TenantConfig, // as we have a flattened field, we should reject all unknown fields in it
+}
+
 #[derive(Serialize, Deserialize)]
 pub struct TenantCreateResponseShard {
     pub shard_id: TenantShardId,
@@ -280,4 +301,19 @@ mod test {
         assert_eq!(serde_json::from_str::<PlacementPolicy>(&encoded)?, v);
         Ok(())
     }
+
+    #[test]
+    fn test_reject_unknown_field() {
+        let id = TenantId::generate();
+        let create_request = serde_json::json!({
+            "new_tenant_id": id.to_string(),
+            "unknown_field": "unknown_value".to_string(),
+        });
+        let err = serde_json::from_value::<TenantCreateRequest>(create_request).unwrap_err();
+        assert!(
+            err.to_string().contains("unknown field `unknown_field`"),
+            "expect unknown field `unknown_field` error, got: {}",
+            err
+        );
+    }
 }

libs/pageserver_api/src/key.rs

@@ -160,8 +160,9 @@ impl Key {
         key
     }
 
-    /// Convert a 18B slice to a key. This function should not be used for metadata keys because field2 is handled differently.
-    /// Use [`Key::from_i128`] instead if you want to handle 16B keys (i.e., metadata keys).
+    /// Convert a 18B slice to a key. This function should not be used for 16B metadata keys because `field2` is handled differently.
+    /// Use [`Key::from_i128`] instead if you want to handle 16B keys (i.e., metadata keys). There are some restrictions on `field2`,
+    /// and therefore not all 18B slices are valid page server keys.
     pub fn from_slice(b: &[u8]) -> Self {
         Key {
             field1: b[0],
@@ -173,7 +174,7 @@ impl Key {
         }
     }
 
-    /// Convert a key to a 18B slice. This function should not be used for metadata keys because field2 is handled differently.
+    /// Convert a key to a 18B slice. This function should not be used for getting a 16B metadata key because `field2` is handled differently.
     /// Use [`Key::to_i128`] instead if you want to get a 16B key (i.e., metadata keys).
     pub fn write_to_byte_slice(&self, buf: &mut [u8]) {
         buf[0] = self.field1;

libs/pageserver_api/src/models.rs

@@ -25,7 +25,6 @@ use utils::{
     serde_system_time,
 };
 
-use crate::controller_api::PlacementPolicy;
 use crate::{
     reltag::RelTag,
     shard::{ShardCount, ShardStripeSize, TenantShardId},
@@ -271,28 +270,6 @@ impl Default for ShardParameters {
     }
 }
 
-#[derive(Serialize, Deserialize, Debug)]
-#[serde(deny_unknown_fields)]
-pub struct TenantCreateRequest {
-    pub new_tenant_id: TenantShardId,
-    #[serde(default)]
-    #[serde(skip_serializing_if = "Option::is_none")]
-    pub generation: Option<u32>,
-
-    // If omitted, create a single shard with TenantShardId::unsharded()
-    #[serde(default)]
-    #[serde(skip_serializing_if = "ShardParameters::is_unsharded")]
-    pub shard_parameters: ShardParameters,
-
-    // This parameter is only meaningful in requests sent to the storage controller
-    #[serde(default)]
-    #[serde(skip_serializing_if = "Option::is_none")]
-    pub placement_policy: Option<PlacementPolicy>,
-
-    #[serde(flatten)]
-    pub config: TenantConfig, // as we have a flattened field, we should reject all unknown fields in it
-}
-
 /// An alternative representation of `pageserver::tenant::TenantConf` with
 /// simpler types.
 #[derive(Serialize, Deserialize, Debug, Default, Clone, Eq, PartialEq)]
@@ -547,10 +524,6 @@ pub struct LocationConfigListResponse {
     pub tenant_shards: Vec<(TenantShardId, Option<LocationConfig>)>,
 }
 
-#[derive(Serialize, Deserialize)]
-#[serde(transparent)]
-pub struct TenantCreateResponse(pub TenantId);
-
 #[derive(Serialize)]
 pub struct StatusResponse {
     pub id: NodeId,
@@ -607,31 +580,6 @@ impl TenantConfigRequest {
     }
 }
 
-#[derive(Debug, Deserialize)]
-pub struct TenantAttachRequest {
-    #[serde(default)]
-    pub config: TenantAttachConfig,
-    #[serde(default)]
-    pub generation: Option<u32>,
-}
-
-/// Newtype to enforce deny_unknown_fields on TenantConfig for
-/// its usage inside `TenantAttachRequest`.
-#[derive(Debug, Serialize, Deserialize, Default)]
-#[serde(deny_unknown_fields)]
-pub struct TenantAttachConfig {
-    #[serde(flatten)]
-    allowing_unknown_fields: TenantConfig,
-}
-
-impl std::ops::Deref for TenantAttachConfig {
-    type Target = TenantConfig;
-
-    fn deref(&self) -> &Self::Target {
-        &self.allowing_unknown_fields
-    }
-}
-
 /// See [`TenantState::attachment_status`] and the OpenAPI docs for context.
 #[derive(Serialize, Deserialize, Clone)]
 #[serde(tag = "slug", content = "data", rename_all = "snake_case")]
@@ -650,8 +598,7 @@ pub struct TenantInfo {
     /// If a layer is present in both local FS and S3, it counts only once.
     pub current_physical_size: Option<u64>, // physical size is only included in `tenant_status` endpoint
     pub attachment_status: TenantAttachmentStatus,
-    #[serde(skip_serializing_if = "Option::is_none")]
-    pub generation: Option<u32>,
+    pub generation: u32,
 }
 
 #[derive(Serialize, Deserialize, Clone)]
@@ -1478,7 +1425,7 @@ mod tests {
             state: TenantState::Active,
             current_physical_size: Some(42),
             attachment_status: TenantAttachmentStatus::Attached,
-            generation: None,
+            generation: 1,
         };
         let expected_active = json!({
             "id": original_active.id.to_string(),
@@ -1488,7 +1435,8 @@ mod tests {
             "current_physical_size": 42,
             "attachment_status": {
                 "slug":"attached",
-            }
+            },
+            "generation" : 1
         });
 
         let original_broken = TenantInfo {
@@ -1499,7 +1447,7 @@ mod tests {
             },
             current_physical_size: Some(42),
             attachment_status: TenantAttachmentStatus::Attached,
-            generation: None,
+            generation: 1,
         };
         let expected_broken = json!({
             "id": original_broken.id.to_string(),
@@ -1513,7 +1461,8 @@ mod tests {
             "current_physical_size": 42,
             "attachment_status": {
                 "slug":"attached",
-            }
+            },
+            "generation" : 1
         });
 
         assert_eq!(
@@ -1531,18 +1480,6 @@ mod tests {
 
     #[test]
     fn test_reject_unknown_field() {
-        let id = TenantId::generate();
-        let create_request = json!({
-            "new_tenant_id": id.to_string(),
-            "unknown_field": "unknown_value".to_string(),
-        });
-        let err = serde_json::from_value::<TenantCreateRequest>(create_request).unwrap_err();
-        assert!(
-            err.to_string().contains("unknown field `unknown_field`"),
-            "expect unknown field `unknown_field` error, got: {}",
-            err
-        );
-
         let id = TenantId::generate();
         let config_request = json!({
             "tenant_id": id.to_string(),
@@ -1554,18 +1491,6 @@ mod tests {
             "expect unknown field `unknown_field` error, got: {}",
             err
         );
-
-        let attach_request = json!({
-            "config": {
-                "unknown_field": "unknown_value".to_string(),
-            },
-        });
-        let err = serde_json::from_value::<TenantAttachRequest>(attach_request).unwrap_err();
-        assert!(
-            err.to_string().contains("unknown field `unknown_field`"),
-            "expect unknown field `unknown_field` error, got: {}",
-            err
-        );
     }
 
     #[test]

libs/postgres_connection/src/lib.rs

@@ -144,20 +144,7 @@ impl PgConnectionConfig {
             // implement and this function is hardly a bottleneck. The function is only called around
             // establishing a new connection.
             #[allow(unstable_name_collisions)]
-            config.options(
-                &self
-                    .options
-                    .iter()
-                    .map(|s| {
-                        if s.contains(['\\', ' ']) {
-                            Cow::Owned(s.replace('\\', "\\\\").replace(' ', "\\ "))
-                        } else {
-                            Cow::Borrowed(s.as_str())
-                        }
-                    })
-                    .intersperse(Cow::Borrowed(" ")) // TODO: use impl from std once it's stabilized
-                    .collect::<String>(),
-            );
+            config.options(&encode_options(&self.options));
         }
         config
     }
@@ -178,6 +165,21 @@ impl PgConnectionConfig {
     }
 }
 
+#[allow(unstable_name_collisions)]
+fn encode_options(options: &[String]) -> String {
+    options
+        .iter()
+        .map(|s| {
+            if s.contains(['\\', ' ']) {
+                Cow::Owned(s.replace('\\', "\\\\").replace(' ', "\\ "))
+            } else {
+                Cow::Borrowed(s.as_str())
+            }
+        })
+        .intersperse(Cow::Borrowed(" ")) // TODO: use impl from std once it's stabilized
+        .collect::<String>()
+}
+
 impl fmt::Display for PgConnectionConfig {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         // The password is intentionally hidden and not part of this display string.
@@ -206,7 +208,7 @@ impl fmt::Debug for PgConnectionConfig {
 
 #[cfg(test)]
 mod tests_pg_connection_config {
-    use crate::PgConnectionConfig;
+    use crate::{encode_options, PgConnectionConfig};
     use once_cell::sync::Lazy;
     use url::Host;
 
@@ -255,18 +257,12 @@ mod tests_pg_connection_config {
 
     #[test]
     fn test_with_options() {
-        let cfg = PgConnectionConfig::new_host_port(STUB_HOST.clone(), 123).extend_options([
-            "hello",
-            "world",
-            "with space",
-            "and \\ backslashes",
+        let options = encode_options(&[
+            "hello".to_owned(),
+            "world".to_owned(),
+            "with space".to_owned(),
+            "and \\ backslashes".to_owned(),
         ]);
-        assert_eq!(cfg.host(), &*STUB_HOST);
-        assert_eq!(cfg.port(), 123);
-        assert_eq!(cfg.raw_address(), "stub.host.example:123");
-        assert_eq!(
-            cfg.to_tokio_postgres_config().get_options(),
-            Some("hello world with\\ space and\\ \\\\\\ backslashes")
-        );
+        assert_eq!(options, "hello world with\\ space and\\ \\\\\\ backslashes");
     }
 }

libs/postgres_ffi/src/xlog_utils.rs

@@ -356,6 +356,28 @@ impl CheckPoint {
         }
         false
     }
+
+    /// Advance next multi-XID/offset to those given in arguments.
+    ///
+    /// It's important that this handles wraparound correctly. This should match the
+    /// MultiXactAdvanceNextMXact() logic in PostgreSQL's xlog_redo() function.
+    ///
+    /// Returns 'true' if the Checkpoint was updated.
+    pub fn update_next_multixid(&mut self, multi_xid: u32, multi_offset: u32) -> bool {
+        let mut modified = false;
+
+        if multi_xid.wrapping_sub(self.nextMulti) as i32 > 0 {
+            self.nextMulti = multi_xid;
+            modified = true;
+        }
+
+        if multi_offset.wrapping_sub(self.nextMultiOffset) as i32 > 0 {
+            self.nextMultiOffset = multi_offset;
+            modified = true;
+        }
+
+        modified
+    }
 }
 
 /// Generate new, empty WAL segment, with correct block headers at the first

libs/postgres_ffi/wal_craft/src/xlog_utils_test.rs

@@ -202,6 +202,53 @@ pub fn test_update_next_xid() {
     assert_eq!(checkpoint.nextXid.value, 2048);
 }
 
+#[test]
+pub fn test_update_next_multixid() {
+    let checkpoint_buf = [0u8; std::mem::size_of::<CheckPoint>()];
+    let mut checkpoint = CheckPoint::decode(&checkpoint_buf).unwrap();
+
+    // simple case
+    checkpoint.nextMulti = 20;
+    checkpoint.nextMultiOffset = 20;
+    checkpoint.update_next_multixid(1000, 2000);
+    assert_eq!(checkpoint.nextMulti, 1000);
+    assert_eq!(checkpoint.nextMultiOffset, 2000);
+
+    // No change
+    checkpoint.update_next_multixid(500, 900);
+    assert_eq!(checkpoint.nextMulti, 1000);
+    assert_eq!(checkpoint.nextMultiOffset, 2000);
+
+    // Close to wraparound, but not wrapped around yet
+    checkpoint.nextMulti = 0xffff0000;
+    checkpoint.nextMultiOffset = 0xfffe0000;
+    checkpoint.update_next_multixid(0xffff00ff, 0xfffe00ff);
+    assert_eq!(checkpoint.nextMulti, 0xffff00ff);
+    assert_eq!(checkpoint.nextMultiOffset, 0xfffe00ff);
+
+    // Wraparound
+    checkpoint.update_next_multixid(1, 900);
+    assert_eq!(checkpoint.nextMulti, 1);
+    assert_eq!(checkpoint.nextMultiOffset, 900);
+
+    // Wraparound nextMulti to 0.
+    //
+    // It's a bit surprising that nextMulti can be 0, because that's a special value
+    // (InvalidMultiXactId). However, that's how Postgres does it at multi-xid wraparound:
+    // nextMulti wraps around to 0, but then when the next multi-xid is assigned, it skips
+    // the 0 and the next multi-xid actually assigned is 1.
+    checkpoint.nextMulti = 0xffff0000;
+    checkpoint.nextMultiOffset = 0xfffe0000;
+    checkpoint.update_next_multixid(0, 0xfffe00ff);
+    assert_eq!(checkpoint.nextMulti, 0);
+    assert_eq!(checkpoint.nextMultiOffset, 0xfffe00ff);
+
+    // Wraparound nextMultiOffset to 0
+    checkpoint.update_next_multixid(0, 0);
+    assert_eq!(checkpoint.nextMulti, 0);
+    assert_eq!(checkpoint.nextMultiOffset, 0);
+}
+
 #[test]
 pub fn test_encode_logical_message() {
     let expected = [

libs/remote_storage/Cargo.toml

@@ -14,8 +14,9 @@ aws-config.workspace = true
 aws-sdk-s3.workspace = true
 aws-credential-types.workspace = true
 bytes.workspace = true
-camino.workspace = true
+camino = { workspace = true, features = ["serde1"] }
 humantime.workspace = true
+humantime-serde.workspace = true
 hyper = { workspace = true, features = ["stream"] }
 futures.workspace = true
 rand.workspace = true

libs/remote_storage/src/azure_blob.rs

@@ -34,7 +34,7 @@ use utils::backoff;
 
 use crate::metrics::{start_measuring_requests, AttemptOutcome, RequestKind};
 use crate::{
-    error::Cancelled, AzureConfig, ConcurrencyLimiter, Download, DownloadError, Listing,
+    config::AzureConfig, error::Cancelled, ConcurrencyLimiter, Download, DownloadError, Listing,
     ListingMode, RemotePath, RemoteStorage, StorageMetadata, TimeTravelError, TimeoutOrCancel,
 };
 

libs/remote_storage/src/config.rs

@@ -0,0 +1,277 @@
+use std::{fmt::Debug, num::NonZeroUsize, str::FromStr, time::Duration};
+
+use anyhow::bail;
+use aws_sdk_s3::types::StorageClass;
+use camino::Utf8PathBuf;
+
+use serde::{Deserialize, Serialize};
+
+use crate::{
+    DEFAULT_MAX_KEYS_PER_LIST_RESPONSE, DEFAULT_REMOTE_STORAGE_AZURE_CONCURRENCY_LIMIT,
+    DEFAULT_REMOTE_STORAGE_S3_CONCURRENCY_LIMIT,
+};
+
+/// External backup storage configuration, enough for creating a client for that storage.
+#[derive(Debug, Clone, PartialEq, Eq, Deserialize, Serialize)]
+pub struct RemoteStorageConfig {
+    /// The storage connection configuration.
+    #[serde(flatten)]
+    pub storage: RemoteStorageKind,
+    /// A common timeout enforced for all requests after concurrency limiter permit has been
+    /// acquired.
+    #[serde(
+        with = "humantime_serde",
+        default = "default_timeout",
+        skip_serializing_if = "is_default_timeout"
+    )]
+    pub timeout: Duration,
+}
+
+fn default_timeout() -> Duration {
+    RemoteStorageConfig::DEFAULT_TIMEOUT
+}
+
+fn is_default_timeout(d: &Duration) -> bool {
+    *d == RemoteStorageConfig::DEFAULT_TIMEOUT
+}
+
+/// A kind of a remote storage to connect to, with its connection configuration.
+#[derive(Debug, Clone, PartialEq, Eq, Deserialize, Serialize)]
+#[serde(untagged)]
+pub enum RemoteStorageKind {
+    /// Storage based on local file system.
+    /// Specify a root folder to place all stored files into.
+    LocalFs { local_path: Utf8PathBuf },
+    /// AWS S3 based storage, storing all files in the S3 bucket
+    /// specified by the config
+    AwsS3(S3Config),
+    /// Azure Blob based storage, storing all files in the container
+    /// specified by the config
+    AzureContainer(AzureConfig),
+}
+
+/// AWS S3 bucket coordinates and access credentials to manage the bucket contents (read and write).
+#[derive(Clone, PartialEq, Eq, Deserialize, Serialize)]
+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,
+    /// A "subfolder" in the bucket, to use the same bucket separately by multiple remote storage users at once.
+    pub prefix_in_bucket: Option<String>,
+    /// A base URL to send S3 requests to.
+    /// By default, the endpoint is derived from a region name, assuming it's
+    /// an AWS S3 region name, erroring on wrong region name.
+    /// Endpoint provides a way to support other S3 flavors and their regions.
+    ///
+    /// Example: `http://127.0.0.1:5000`
+    pub endpoint: Option<String>,
+    /// AWS S3 has various limits on its API calls, we need not to exceed those.
+    /// See [`DEFAULT_REMOTE_STORAGE_S3_CONCURRENCY_LIMIT`] for more details.
+    #[serde(default = "default_remote_storage_s3_concurrency_limit")]
+    pub concurrency_limit: NonZeroUsize,
+    #[serde(default = "default_max_keys_per_list_response")]
+    pub max_keys_per_list_response: Option<i32>,
+    #[serde(
+        deserialize_with = "deserialize_storage_class",
+        serialize_with = "serialize_storage_class",
+        default
+    )]
+    pub upload_storage_class: Option<StorageClass>,
+}
+
+fn default_remote_storage_s3_concurrency_limit() -> NonZeroUsize {
+    DEFAULT_REMOTE_STORAGE_S3_CONCURRENCY_LIMIT
+        .try_into()
+        .unwrap()
+}
+
+fn default_max_keys_per_list_response() -> Option<i32> {
+    DEFAULT_MAX_KEYS_PER_LIST_RESPONSE
+}
+
+impl 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)
+            .field("prefix_in_bucket", &self.prefix_in_bucket)
+            .field("concurrency_limit", &self.concurrency_limit)
+            .field(
+                "max_keys_per_list_response",
+                &self.max_keys_per_list_response,
+            )
+            .finish()
+    }
+}
+
+/// Azure  bucket coordinates and access credentials to manage the bucket contents (read and write).
+#[derive(Clone, PartialEq, Eq, Serialize, Deserialize)]
+pub struct AzureConfig {
+    /// Name of the container to connect to.
+    pub container_name: String,
+    /// Name of the storage account the container is inside of
+    pub storage_account: Option<String>,
+    /// The region where the bucket is located at.
+    pub container_region: String,
+    /// A "subfolder" in the container, to use the same container separately by multiple remote storage users at once.
+    pub prefix_in_container: Option<String>,
+    /// Azure has various limits on its API calls, we need not to exceed those.
+    /// See [`DEFAULT_REMOTE_STORAGE_AZURE_CONCURRENCY_LIMIT`] for more details.
+    #[serde(default = "default_remote_storage_azure_concurrency_limit")]
+    pub concurrency_limit: NonZeroUsize,
+    #[serde(default = "default_max_keys_per_list_response")]
+    pub max_keys_per_list_response: Option<i32>,
+}
+
+fn default_remote_storage_azure_concurrency_limit() -> NonZeroUsize {
+    NonZeroUsize::new(DEFAULT_REMOTE_STORAGE_AZURE_CONCURRENCY_LIMIT).unwrap()
+}
+
+impl Debug for AzureConfig {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("AzureConfig")
+            .field("bucket_name", &self.container_name)
+            .field("storage_account", &self.storage_account)
+            .field("bucket_region", &self.container_region)
+            .field("prefix_in_container", &self.prefix_in_container)
+            .field("concurrency_limit", &self.concurrency_limit)
+            .field(
+                "max_keys_per_list_response",
+                &self.max_keys_per_list_response,
+            )
+            .finish()
+    }
+}
+
+fn deserialize_storage_class<'de, D: serde::Deserializer<'de>>(
+    deserializer: D,
+) -> Result<Option<StorageClass>, D::Error> {
+    Option::<String>::deserialize(deserializer).and_then(|s| {
+        if let Some(s) = s {
+            use serde::de::Error;
+            let storage_class = StorageClass::from_str(&s).expect("infallible");
+            #[allow(deprecated)]
+            if matches!(storage_class, StorageClass::Unknown(_)) {
+                return Err(D::Error::custom(format!(
+                    "Specified storage class unknown to SDK: '{s}'. Allowed values: {:?}",
+                    StorageClass::values()
+                )));
+            }
+            Ok(Some(storage_class))
+        } else {
+            Ok(None)
+        }
+    })
+}
+
+fn serialize_storage_class<S: serde::Serializer>(
+    val: &Option<StorageClass>,
+    serializer: S,
+) -> Result<S::Ok, S::Error> {
+    let val = val.as_ref().map(StorageClass::as_str);
+    Option::<&str>::serialize(&val, serializer)
+}
+
+impl RemoteStorageConfig {
+    pub const DEFAULT_TIMEOUT: Duration = std::time::Duration::from_secs(120);
+
+    pub fn from_toml(toml: &toml_edit::Item) -> anyhow::Result<Option<RemoteStorageConfig>> {
+        let document: toml_edit::Document = match toml {
+            toml_edit::Item::Table(toml) => toml.clone().into(),
+            toml_edit::Item::Value(toml_edit::Value::InlineTable(toml)) => {
+                toml.clone().into_table().into()
+            }
+            _ => bail!("toml not a table or inline table"),
+        };
+
+        if document.is_empty() {
+            return Ok(None);
+        }
+
+        Ok(Some(toml_edit::de::from_document(document)?))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn parse(input: &str) -> anyhow::Result<Option<RemoteStorageConfig>> {
+        let toml = input.parse::<toml_edit::Document>().unwrap();
+        RemoteStorageConfig::from_toml(toml.as_item())
+    }
+
+    #[test]
+    fn parse_localfs_config_with_timeout() {
+        let input = "local_path = '.'
+timeout = '5s'";
+
+        let config = parse(input).unwrap().expect("it exists");
+
+        assert_eq!(
+            config,
+            RemoteStorageConfig {
+                storage: RemoteStorageKind::LocalFs {
+                    local_path: Utf8PathBuf::from(".")
+                },
+                timeout: Duration::from_secs(5)
+            }
+        );
+    }
+
+    #[test]
+    fn test_s3_parsing() {
+        let toml = "\
+    bucket_name = 'foo-bar'
+    bucket_region = 'eu-central-1'
+    upload_storage_class = 'INTELLIGENT_TIERING'
+    timeout = '7s'
+    ";
+
+        let config = parse(toml).unwrap().expect("it exists");
+
+        assert_eq!(
+            config,
+            RemoteStorageConfig {
+                storage: RemoteStorageKind::AwsS3(S3Config {
+                    bucket_name: "foo-bar".into(),
+                    bucket_region: "eu-central-1".into(),
+                    prefix_in_bucket: None,
+                    endpoint: None,
+                    concurrency_limit: default_remote_storage_s3_concurrency_limit(),
+                    max_keys_per_list_response: DEFAULT_MAX_KEYS_PER_LIST_RESPONSE,
+                    upload_storage_class: Some(StorageClass::IntelligentTiering),
+                }),
+                timeout: Duration::from_secs(7)
+            }
+        );
+    }
+
+    #[test]
+    fn test_azure_parsing() {
+        let toml = "\
+    container_name = 'foo-bar'
+    container_region = 'westeurope'
+    upload_storage_class = 'INTELLIGENT_TIERING'
+    timeout = '7s'
+    ";
+
+        let config = parse(toml).unwrap().expect("it exists");
+
+        assert_eq!(
+            config,
+            RemoteStorageConfig {
+                storage: RemoteStorageKind::AzureContainer(AzureConfig {
+                    container_name: "foo-bar".into(),
+                    storage_account: None,
+                    container_region: "westeurope".into(),
+                    prefix_in_container: None,
+                    concurrency_limit: default_remote_storage_azure_concurrency_limit(),
+                    max_keys_per_list_response: DEFAULT_MAX_KEYS_PER_LIST_RESPONSE,
+                }),
+                timeout: Duration::from_secs(7)
+            }
+        );
+    }
+}

libs/remote_storage/src/lib.rs

@@ -10,6 +10,7 @@
 #![deny(clippy::undocumented_unsafe_blocks)]
 
 mod azure_blob;
+mod config;
 mod error;
 mod local_fs;
 mod metrics;
@@ -18,17 +19,10 @@ mod simulate_failures;
 mod support;
 
 use std::{
-    collections::HashMap,
-    fmt::Debug,
-    num::{NonZeroU32, NonZeroUsize},
-    pin::Pin,
-    str::FromStr,
-    sync::Arc,
-    time::{Duration, SystemTime},
+    collections::HashMap, fmt::Debug, num::NonZeroU32, pin::Pin, sync::Arc, time::SystemTime,
 };
 
-use anyhow::{bail, Context};
-use aws_sdk_s3::types::StorageClass;
+use anyhow::Context;
 use camino::{Utf8Path, Utf8PathBuf};
 
 use bytes::Bytes;
@@ -36,7 +30,6 @@ use futures::stream::Stream;
 use serde::{Deserialize, Serialize};
 use tokio::sync::Semaphore;
 use tokio_util::sync::CancellationToken;
-use toml_edit::Item;
 use tracing::info;
 
 pub use self::{
@@ -45,6 +38,8 @@ pub use self::{
 };
 use s3_bucket::RequestKind;
 
+pub use crate::config::{AzureConfig, RemoteStorageConfig, RemoteStorageKind, S3Config};
+
 /// Azure SDK's ETag type is a simple String wrapper: we use this internally instead of repeating it here.
 pub use azure_core::Etag;
 
@@ -451,7 +446,7 @@ impl GenericRemoteStorage {
     pub fn from_config(storage_config: &RemoteStorageConfig) -> anyhow::Result<Self> {
         let timeout = storage_config.timeout;
         Ok(match &storage_config.storage {
-            RemoteStorageKind::LocalFs(path) => {
+            RemoteStorageKind::LocalFs { local_path: path } => {
                 info!("Using fs root '{path}' as a remote storage");
                 Self::LocalFs(LocalFs::new(path.clone(), timeout)?)
             }
@@ -526,262 +521,6 @@ impl<const N: usize> From<[(&str, &str); N]> for StorageMetadata {
     }
 }
 
-/// External backup storage configuration, enough for creating a client for that storage.
-#[derive(Debug, Clone, PartialEq, Eq)]
-pub struct RemoteStorageConfig {
-    /// The storage connection configuration.
-    pub storage: RemoteStorageKind,
-    /// A common timeout enforced for all requests after concurrency limiter permit has been
-    /// acquired.
-    pub timeout: Duration,
-}
-
-/// A kind of a remote storage to connect to, with its connection configuration.
-#[derive(Debug, Clone, PartialEq, Eq)]
-pub enum RemoteStorageKind {
-    /// Storage based on local file system.
-    /// Specify a root folder to place all stored files into.
-    LocalFs(Utf8PathBuf),
-    /// AWS S3 based storage, storing all files in the S3 bucket
-    /// specified by the config
-    AwsS3(S3Config),
-    /// Azure Blob based storage, storing all files in the container
-    /// specified by the config
-    AzureContainer(AzureConfig),
-}
-
-/// AWS S3 bucket coordinates and access credentials to manage the bucket contents (read and write).
-#[derive(Clone, PartialEq, Eq)]
-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,
-    /// A "subfolder" in the bucket, to use the same bucket separately by multiple remote storage users at once.
-    pub prefix_in_bucket: Option<String>,
-    /// A base URL to send S3 requests to.
-    /// By default, the endpoint is derived from a region name, assuming it's
-    /// an AWS S3 region name, erroring on wrong region name.
-    /// Endpoint provides a way to support other S3 flavors and their regions.
-    ///
-    /// Example: `http://127.0.0.1:5000`
-    pub endpoint: Option<String>,
-    /// AWS S3 has various limits on its API calls, we need not to exceed those.
-    /// See [`DEFAULT_REMOTE_STORAGE_S3_CONCURRENCY_LIMIT`] for more details.
-    pub concurrency_limit: NonZeroUsize,
-    pub max_keys_per_list_response: Option<i32>,
-    pub upload_storage_class: Option<StorageClass>,
-}
-
-impl 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)
-            .field("prefix_in_bucket", &self.prefix_in_bucket)
-            .field("concurrency_limit", &self.concurrency_limit)
-            .field(
-                "max_keys_per_list_response",
-                &self.max_keys_per_list_response,
-            )
-            .finish()
-    }
-}
-
-/// Azure  bucket coordinates and access credentials to manage the bucket contents (read and write).
-#[derive(Clone, PartialEq, Eq)]
-pub struct AzureConfig {
-    /// Name of the container to connect to.
-    pub container_name: String,
-    /// Name of the storage account the container is inside of
-    pub storage_account: Option<String>,
-    /// The region where the bucket is located at.
-    pub container_region: String,
-    /// A "subfolder" in the container, to use the same container separately by multiple remote storage users at once.
-    pub prefix_in_container: Option<String>,
-    /// Azure has various limits on its API calls, we need not to exceed those.
-    /// See [`DEFAULT_REMOTE_STORAGE_AZURE_CONCURRENCY_LIMIT`] for more details.
-    pub concurrency_limit: NonZeroUsize,
-    pub max_keys_per_list_response: Option<i32>,
-}
-
-impl Debug for AzureConfig {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        f.debug_struct("AzureConfig")
-            .field("bucket_name", &self.container_name)
-            .field("storage_account", &self.storage_account)
-            .field("bucket_region", &self.container_region)
-            .field("prefix_in_container", &self.prefix_in_container)
-            .field("concurrency_limit", &self.concurrency_limit)
-            .field(
-                "max_keys_per_list_response",
-                &self.max_keys_per_list_response,
-            )
-            .finish()
-    }
-}
-
-impl RemoteStorageConfig {
-    pub const DEFAULT_TIMEOUT: Duration = std::time::Duration::from_secs(120);
-
-    pub fn from_toml(toml: &toml_edit::Item) -> anyhow::Result<Option<RemoteStorageConfig>> {
-        let local_path = toml.get("local_path");
-        let bucket_name = toml.get("bucket_name");
-        let bucket_region = toml.get("bucket_region");
-        let container_name = toml.get("container_name");
-        let container_region = toml.get("container_region");
-
-        let use_azure = container_name.is_some() && container_region.is_some();
-
-        let default_concurrency_limit = if use_azure {
-            DEFAULT_REMOTE_STORAGE_AZURE_CONCURRENCY_LIMIT
-        } else {
-            DEFAULT_REMOTE_STORAGE_S3_CONCURRENCY_LIMIT
-        };
-        let concurrency_limit = NonZeroUsize::new(
-            parse_optional_integer("concurrency_limit", toml)?.unwrap_or(default_concurrency_limit),
-        )
-        .context("Failed to parse 'concurrency_limit' as a positive integer")?;
-
-        let max_keys_per_list_response =
-            parse_optional_integer::<i32, _>("max_keys_per_list_response", toml)
-                .context("Failed to parse 'max_keys_per_list_response' as a positive integer")?
-                .or(DEFAULT_MAX_KEYS_PER_LIST_RESPONSE);
-
-        let endpoint = toml
-            .get("endpoint")
-            .map(|endpoint| parse_toml_string("endpoint", endpoint))
-            .transpose()?;
-
-        let timeout = toml
-            .get("timeout")
-            .map(|timeout| {
-                timeout
-                    .as_str()
-                    .ok_or_else(|| anyhow::Error::msg("timeout was not a string"))
-            })
-            .transpose()
-            .and_then(|timeout| {
-                timeout
-                    .map(humantime::parse_duration)
-                    .transpose()
-                    .map_err(anyhow::Error::new)
-            })
-            .context("parse timeout")?
-            .unwrap_or(Self::DEFAULT_TIMEOUT);
-
-        if timeout < Duration::from_secs(1) {
-            bail!("timeout was specified as {timeout:?} which is too low");
-        }
-
-        let storage = match (
-            local_path,
-            bucket_name,
-            bucket_region,
-            container_name,
-            container_region,
-        ) {
-            // no 'local_path' nor 'bucket_name' options are provided, consider this remote storage disabled
-            (None, None, None, None, None) => return Ok(None),
-            (_, Some(_), None, ..) => {
-                bail!("'bucket_region' option is mandatory if 'bucket_name' is given ")
-            }
-            (_, None, Some(_), ..) => {
-                bail!("'bucket_name' option is mandatory if 'bucket_region' is given ")
-            }
-            (None, Some(bucket_name), Some(bucket_region), ..) => {
-                RemoteStorageKind::AwsS3(S3Config {
-                    bucket_name: parse_toml_string("bucket_name", bucket_name)?,
-                    bucket_region: parse_toml_string("bucket_region", bucket_region)?,
-                    prefix_in_bucket: toml
-                        .get("prefix_in_bucket")
-                        .map(|prefix_in_bucket| {
-                            parse_toml_string("prefix_in_bucket", prefix_in_bucket)
-                        })
-                        .transpose()?,
-                    endpoint,
-                    concurrency_limit,
-                    max_keys_per_list_response,
-                    upload_storage_class: toml
-                        .get("upload_storage_class")
-                        .map(|prefix_in_bucket| -> anyhow::Result<_> {
-                            let s = parse_toml_string("upload_storage_class", prefix_in_bucket)?;
-                            let storage_class = StorageClass::from_str(&s).expect("infallible");
-                            #[allow(deprecated)]
-                            if matches!(storage_class, StorageClass::Unknown(_)) {
-                                bail!("Specified storage class unknown to SDK: '{s}'. Allowed values: {:?}", StorageClass::values());
-                            }
-                            Ok(storage_class)
-                        })
-                        .transpose()?,
-                })
-            }
-            (_, _, _, Some(_), None) => {
-                bail!("'container_name' option is mandatory if 'container_region' is given ")
-            }
-            (_, _, _, None, Some(_)) => {
-                bail!("'container_name' option is mandatory if 'container_region' is given ")
-            }
-            (None, None, None, Some(container_name), Some(container_region)) => {
-                RemoteStorageKind::AzureContainer(AzureConfig {
-                    container_name: parse_toml_string("container_name", container_name)?,
-                    storage_account: toml
-                        .get("storage_account")
-                        .map(|storage_account| {
-                            parse_toml_string("storage_account", storage_account)
-                        })
-                        .transpose()?,
-                    container_region: parse_toml_string("container_region", container_region)?,
-                    prefix_in_container: toml
-                        .get("prefix_in_container")
-                        .map(|prefix_in_container| {
-                            parse_toml_string("prefix_in_container", prefix_in_container)
-                        })
-                        .transpose()?,
-                    concurrency_limit,
-                    max_keys_per_list_response,
-                })
-            }
-            (Some(local_path), None, None, None, None) => RemoteStorageKind::LocalFs(
-                Utf8PathBuf::from(parse_toml_string("local_path", local_path)?),
-            ),
-            (Some(_), Some(_), ..) => {
-                bail!("'local_path' and 'bucket_name' are mutually exclusive")
-            }
-            (Some(_), _, _, Some(_), Some(_)) => {
-                bail!("local_path and 'container_name' are mutually exclusive")
-            }
-        };
-
-        Ok(Some(RemoteStorageConfig { storage, timeout }))
-    }
-}
-
-// Helper functions to parse a toml Item
-fn parse_optional_integer<I, E>(name: &str, item: &toml_edit::Item) -> anyhow::Result<Option<I>>
-where
-    I: TryFrom<i64, Error = E>,
-    E: std::error::Error + Send + Sync + 'static,
-{
-    let toml_integer = match item.get(name) {
-        Some(item) => item
-            .as_integer()
-            .with_context(|| format!("configure option {name} is not an integer"))?,
-        None => return Ok(None),
-    };
-
-    I::try_from(toml_integer)
-        .map(Some)
-        .with_context(|| format!("configure option {name} is too large"))
-}
-
-fn parse_toml_string(name: &str, item: &Item) -> anyhow::Result<String> {
-    let s = item
-        .as_str()
-        .with_context(|| format!("configure option {name} is not a string"))?;
-    Ok(s.to_string())
-}
-
 struct ConcurrencyLimiter {
     // Every request to S3 can be throttled or cancelled, if a certain number of requests per second is exceeded.
     // Same goes to IAM, which is queried before every S3 request, if enabled. IAM has even lower RPS threshold.
@@ -849,24 +588,4 @@ mod tests {
         let err = RemotePath::new(Utf8Path::new("/")).expect_err("Should fail on absolute paths");
         assert_eq!(err.to_string(), "Path \"/\" is not relative");
     }
-
-    #[test]
-    fn parse_localfs_config_with_timeout() {
-        let input = "local_path = '.'
-timeout = '5s'";
-
-        let toml = input.parse::<toml_edit::Document>().unwrap();
-
-        let config = RemoteStorageConfig::from_toml(toml.as_item())
-            .unwrap()
-            .expect("it exists");
-
-        assert_eq!(
-            config,
-            RemoteStorageConfig {
-                storage: RemoteStorageKind::LocalFs(Utf8PathBuf::from(".")),
-                timeout: Duration::from_secs(5)
-            }
-        );
-    }
 }

libs/remote_storage/src/s3_bucket.rs

@@ -46,12 +46,12 @@ use utils::backoff;
 
 use super::StorageMetadata;
 use crate::{
+    config::S3Config,
     error::Cancelled,
     metrics::{start_counting_cancelled_wait, start_measuring_requests},
     support::PermitCarrying,
     ConcurrencyLimiter, Download, DownloadError, Listing, ListingMode, RemotePath, RemoteStorage,
-    S3Config, TimeTravelError, TimeoutOrCancel, MAX_KEYS_PER_DELETE,
-    REMOTE_STORAGE_PREFIX_SEPARATOR,
+    TimeTravelError, TimeoutOrCancel, MAX_KEYS_PER_DELETE, REMOTE_STORAGE_PREFIX_SEPARATOR,
 };
 
 use crate::metrics::AttemptOutcome;

libs/utils/src/generation.rs

@@ -9,20 +9,11 @@ use serde::{Deserialize, Serialize};
 /// numbers are used.
 #[derive(Copy, Clone, Eq, PartialEq, PartialOrd, Ord, Hash)]
 pub enum Generation {
-    // Generations with this magic value will not add a suffix to S3 keys, and will not
-    // be included in persisted index_part.json.  This value is only to be used
-    // during migration from pre-generation metadata to generation-aware metadata,
-    // and should eventually go away.
-    //
-    // A special Generation is used rather than always wrapping Generation in an Option,
-    // so that code handling generations doesn't have to be aware of the legacy
-    // case everywhere it touches a generation.
+    // The None Generation is used in the metadata of layers written before generations were
+    // introduced.  A running Tenant always has a valid generation, but the layer metadata may
+    // include None generations.
     None,
-    // Generations with this magic value may never be used to construct S3 keys:
-    // we will panic if someone tries to.  This is for Tenants in the "Broken" state,
-    // so that we can satisfy their constructor with a Generation without risking
-    // a code bug using it in an S3 write (broken tenants should never write)
-    Broken,
+
     Valid(u32),
 }
 
@@ -42,11 +33,6 @@ impl Generation {
         Self::None
     }
 
-    // Create a new generation that will panic if you try to use get_suffix
-    pub fn broken() -> Self {
-        Self::Broken
-    }
-
     pub const fn new(v: u32) -> Self {
         Self::Valid(v)
     }
@@ -60,9 +46,6 @@ impl Generation {
         match self {
             Self::Valid(v) => GenerationFileSuffix(Some(*v)),
             Self::None => GenerationFileSuffix(None),
-            Self::Broken => {
-                panic!("Tried to use a broken generation");
-            }
         }
     }
 
@@ -86,7 +69,6 @@ impl Generation {
                 }
             }
             Self::None => Self::None,
-            Self::Broken => panic!("Attempted to use a broken generation"),
         }
     }
 
@@ -95,7 +77,6 @@ impl Generation {
         match self {
             Self::Valid(n) => Self::Valid(*n + 1),
             Self::None => Self::Valid(1),
-            Self::Broken => panic!("Attempted to use a broken generation"),
         }
     }
 
@@ -128,7 +109,7 @@ impl Serialize for Generation {
         if let Self::Valid(v) = self {
             v.serialize(serializer)
         } else {
-            // We should never be asked to serialize a None or Broken.  Structures
+            // We should never be asked to serialize a None. Structures
             // that include an optional generation should convert None to an
             // Option<Generation>::None
             Err(serde::ser::Error::custom(
@@ -159,9 +140,6 @@ impl Debug for Generation {
             Self::None => {
                 write!(f, "<none>")
             }
-            Self::Broken => {
-                write!(f, "<broken>")
-            }
         }
     }
 }

libs/utils/src/http/json.rs

@@ -8,22 +8,15 @@ use super::error::ApiError;
 pub async fn json_request<T: for<'de> Deserialize<'de>>(
     request: &mut Request<Body>,
 ) -> Result<T, ApiError> {
-    json_request_or_empty_body(request)
-        .await?
-        .context("missing request body")
-        .map_err(ApiError::BadRequest)
-}
-
-/// Will be removed as part of <https://github.com/neondatabase/neon/issues/4282>
-pub async fn json_request_or_empty_body<T: for<'de> Deserialize<'de>>(
-    request: &mut Request<Body>,
-) -> Result<Option<T>, ApiError> {
     let body = hyper::body::aggregate(request.body_mut())
         .await
         .context("Failed to read request body")
         .map_err(ApiError::BadRequest)?;
+
     if body.remaining() == 0 {
-        return Ok(None);
+        return Err(ApiError::BadRequest(anyhow::anyhow!(
+            "missing request body"
+        )));
     }
 
     let mut deser = serde_json::de::Deserializer::from_reader(body.reader());
@@ -31,7 +24,6 @@ pub async fn json_request_or_empty_body<T: for<'de> Deserialize<'de>>(
     serde_path_to_error::deserialize(&mut deser)
         // intentionally stringify because the debug version is not helpful in python logs
         .map_err(|e| anyhow::anyhow!("Failed to parse json request: {e}"))
-        .map(Some)
         .map_err(ApiError::BadRequest)
 }
 

libs/walproposer/src/walproposer.rs

@@ -1,3 +1,5 @@
+#![allow(clippy::todo)]
+
 use std::ffi::CString;
 
 use crate::{

pageserver/benches/bench_walredo.rs

@@ -48,6 +48,7 @@
 //! medium/128        time:   [8.8311 ms 8.9849 ms 9.1263 ms]
 //! ```
 
+use anyhow::Context;
 use bytes::{Buf, Bytes};
 use criterion::{BenchmarkId, Criterion};
 use pageserver::{config::PageServerConf, walrecord::NeonWalRecord, walredo::PostgresRedoManager};
@@ -188,6 +189,7 @@ impl Request {
         manager
             .request_redo(*key, *lsn, base_img.clone(), records.clone(), *pg_version)
             .await
+            .context("request_redo")
     }
 
     fn pg_record(will_init: bool, bytes: &'static [u8]) -> NeonWalRecord {

pageserver/client/src/mgmt_api.rs

@@ -205,15 +205,6 @@ impl Client {
         Ok(())
     }
 
-    pub async fn tenant_create(&self, req: &TenantCreateRequest) -> Result<TenantId> {
-        let uri = format!("{}/v1/tenant", self.mgmt_api_endpoint);
-        self.request(Method::POST, &uri, req)
-            .await?
-            .json()
-            .await
-            .map_err(Error::ReceiveBody)
-    }
-
     /// The tenant deletion API can return 202 if deletion is incomplete, or
     /// 404 if it is complete.  Callers are responsible for checking the status
     /// code and retrying.  Error codes other than 404 will return Err().

pageserver/ctl/src/draw_timeline_dir.rs

@@ -83,10 +83,18 @@ fn parse_filename(name: &str) -> (Range<Key>, Range<Lsn>) {
     let keys: Vec<&str> = split[0].split('-').collect();
     let mut lsns: Vec<&str> = split[1].split('-').collect();
 
+    // The current format of the layer file name: 000000067F0000000400000B150100000000-000000067F0000000400000D350100000000__00000000014B7AC8-v1-00000001
+
+    // Handle generation number `-00000001` part
     if lsns.last().expect("should").len() == 8 {
         lsns.pop();
     }
 
+    // Handle version number `-v1` part
+    if lsns.last().expect("should").starts_with('v') {
+        lsns.pop();
+    }
+
     if lsns.len() == 1 {
         lsns.push(lsns[0]);
     }

pageserver/src/config.rs

@@ -33,15 +33,10 @@ use utils::{
 use crate::tenant::timeline::GetVectoredImpl;
 use crate::tenant::vectored_blob_io::MaxVectoredReadBytes;
 use crate::tenant::{config::TenantConfOpt, timeline::GetImpl};
-use crate::tenant::{
-    TENANTS_SEGMENT_NAME, TENANT_DELETED_MARKER_FILE_NAME, TIMELINES_SEGMENT_NAME,
-};
+use crate::tenant::{TENANTS_SEGMENT_NAME, TIMELINES_SEGMENT_NAME};
 use crate::{disk_usage_eviction_task::DiskUsageEvictionTaskConfig, virtual_file::io_engine};
 use crate::{tenant::config::TenantConf, virtual_file};
-use crate::{
-    TENANT_CONFIG_NAME, TENANT_HEATMAP_BASENAME, TENANT_LOCATION_CONFIG_NAME,
-    TIMELINE_DELETE_MARK_SUFFIX,
-};
+use crate::{TENANT_HEATMAP_BASENAME, TENANT_LOCATION_CONFIG_NAME, TIMELINE_DELETE_MARK_SUFFIX};
 
 use self::defaults::DEFAULT_CONCURRENT_TENANT_WARMUP;
 
@@ -812,15 +807,11 @@ impl PageServerConf {
     }
 
     /// Points to a place in pageserver's local directory,
-    /// where certain tenant's tenantconf file should be located.
-    ///
-    /// Legacy: superseded by tenant_location_config_path.  Eventually
-    /// remove this function.
-    pub fn tenant_config_path(&self, tenant_shard_id: &TenantShardId) -> Utf8PathBuf {
-        self.tenant_path(tenant_shard_id).join(TENANT_CONFIG_NAME)
-    }
-
-    pub fn tenant_location_config_path(&self, tenant_shard_id: &TenantShardId) -> Utf8PathBuf {
+    /// where certain tenant's LocationConf be stored.
+    pub(crate) fn tenant_location_config_path(
+        &self,
+        tenant_shard_id: &TenantShardId,
+    ) -> Utf8PathBuf {
         self.tenant_path(tenant_shard_id)
             .join(TENANT_LOCATION_CONFIG_NAME)
     }
@@ -855,14 +846,6 @@ impl PageServerConf {
         )
     }
 
-    pub(crate) fn tenant_deleted_mark_file_path(
-        &self,
-        tenant_shard_id: &TenantShardId,
-    ) -> Utf8PathBuf {
-        self.tenant_path(tenant_shard_id)
-            .join(TENANT_DELETED_MARKER_FILE_NAME)
-    }
-
     pub fn traces_path(&self) -> Utf8PathBuf {
         self.workdir.join("traces")
     }
@@ -1463,7 +1446,7 @@ broker_endpoint = '{broker_endpoint}'
             assert_eq!(
                 parsed_remote_storage_config,
                 RemoteStorageConfig {
-                    storage: RemoteStorageKind::LocalFs(local_storage_path.clone()),
+                    storage: RemoteStorageKind::LocalFs { local_path: local_storage_path.clone() },
                     timeout: RemoteStorageConfig::DEFAULT_TIMEOUT,
                 },
                 "Remote storage config should correctly parse the local FS config and fill other storage defaults"

pageserver/src/deletion_queue.rs

@@ -382,17 +382,6 @@ pub enum DeletionQueueError {
 }
 
 impl DeletionQueueClient {
-    pub(crate) fn broken() -> Self {
-        // Channels whose receivers are immediately dropped.
-        let (tx, _rx) = tokio::sync::mpsc::unbounded_channel();
-        let (executor_tx, _executor_rx) = tokio::sync::mpsc::channel(1);
-        Self {
-            tx,
-            executor_tx,
-            lsn_table: Arc::default(),
-        }
-    }
-
     /// This is cancel-safe.  If you drop the future before it completes, the message
     /// is not pushed, although in the context of the deletion queue it doesn't matter: once
     /// we decide to do a deletion the decision is always final.
@@ -850,7 +839,9 @@ mod test {
         std::fs::create_dir_all(remote_fs_dir)?;
         let remote_fs_dir = harness.conf.workdir.join("remote_fs").canonicalize_utf8()?;
         let storage_config = RemoteStorageConfig {
-            storage: RemoteStorageKind::LocalFs(remote_fs_dir.clone()),
+            storage: RemoteStorageKind::LocalFs {
+                local_path: remote_fs_dir.clone(),
+            },
             timeout: RemoteStorageConfig::DEFAULT_TIMEOUT,
         };
         let storage = GenericRemoteStorage::from_config(&storage_config).unwrap();

pageserver/src/http/openapi_spec.yml

@@ -236,6 +236,13 @@ paths:
             type: string
             format: date-time
           description: A timestamp to get the LSN
+        - name: with_lease
+          in: query
+          required: false
+          schema:
+            type: boolean
+          description: Whether to grant a lease to the corresponding LSN. Default to false.
+
       responses:
         "200":
           description: OK
@@ -360,16 +367,7 @@ paths:
                 $ref: "#/components/schemas/TenantLocationConfigResponse"
         "409":
           description: |
-            The tenant is already known to Pageserver in some way,
-            and hence this `/attach` call has been rejected.
-
-            Some examples of how this can happen:
-            - tenant was created on this pageserver
-            - tenant attachment was started by an earlier call to `/attach`.
-
-            Callers should poll the tenant status's `attachment_status` field,
-            like for status 202. See the longer description for `POST /attach`
-            for details.
+            The tenant is already being modified, perhaps by a concurrent call to this API
           content:
             application/json:
               schema:
@@ -755,8 +753,6 @@ components:
               For example this can be caused by s3 being unreachable. The retry may be implemented
               with call to detach, though it would be better to not automate it and inspec failed state
               manually before proceeding with a retry.
-
-            See the tenant `/attach` endpoint for more information.
           type: object
           required:
             - slug
@@ -1029,6 +1025,10 @@ components:
         kind:
           type: string
           enum: [past, present, future, nodata]
+        valid_until:
+          type: string
+          format: date-time
+          description: The expiration time of the granted lease.
 
     LsnLease:
       type: object

pageserver/src/http/routes.rs

@@ -21,6 +21,7 @@ use pageserver_api::models::IngestAuxFilesRequest;
 use pageserver_api::models::ListAuxFilesRequest;
 use pageserver_api::models::LocationConfig;
 use pageserver_api::models::LocationConfigListResponse;
+use pageserver_api::models::LsnLease;
 use pageserver_api::models::ShardParameters;
 use pageserver_api::models::TenantDetails;
 use pageserver_api::models::TenantLocationConfigResponse;
@@ -30,13 +31,11 @@ use pageserver_api::models::TenantShardLocation;
 use pageserver_api::models::TenantShardSplitRequest;
 use pageserver_api::models::TenantShardSplitResponse;
 use pageserver_api::models::TenantSorting;
-use pageserver_api::models::TenantState;
 use pageserver_api::models::TopTenantShardItem;
 use pageserver_api::models::TopTenantShardsRequest;
 use pageserver_api::models::TopTenantShardsResponse;
 use pageserver_api::models::{
-    DownloadRemoteLayersTaskSpawnRequest, LocationConfigMode, TenantAttachRequest,
-    TenantLocationConfigRequest,
+    DownloadRemoteLayersTaskSpawnRequest, LocationConfigMode, TenantLocationConfigRequest,
 };
 use pageserver_api::shard::ShardCount;
 use pageserver_api::shard::TenantShardId;
@@ -50,12 +49,10 @@ use utils::auth::JwtAuth;
 use utils::failpoint_support::failpoints_handler;
 use utils::http::endpoint::prometheus_metrics_handler;
 use utils::http::endpoint::request_span;
-use utils::http::json::json_request_or_empty_body;
 use utils::http::request::{get_request_param, must_get_query_param, parse_query_param};
 
 use crate::context::{DownloadBehavior, RequestContext};
 use crate::deletion_queue::DeletionQueueClient;
-use crate::metrics::{StorageTimeOperation, STORAGE_TIME_GLOBAL};
 use crate::pgdatadir_mapping::LsnForTimestamp;
 use crate::task_mgr::TaskKind;
 use crate::tenant::config::{LocationConf, TenantConfOpt};
@@ -77,13 +74,12 @@ use crate::tenant::timeline::CompactFlags;
 use crate::tenant::timeline::CompactionError;
 use crate::tenant::timeline::Timeline;
 use crate::tenant::GetTimelineError;
-use crate::tenant::SpawnMode;
 use crate::tenant::{LogicalSizeCalculationCause, PageReconstructError};
 use crate::{config::PageServerConf, tenant::mgr};
 use crate::{disk_usage_eviction_task, tenant};
 use pageserver_api::models::{
-    StatusResponse, TenantConfigRequest, TenantCreateRequest, TenantCreateResponse, TenantInfo,
-    TimelineCreateRequest, TimelineGcRequest, TimelineInfo,
+    StatusResponse, TenantConfigRequest, TenantInfo, TimelineCreateRequest, TimelineGcRequest,
+    TimelineInfo,
 };
 use utils::{
     auth::SwappableJwtAuth,
@@ -329,14 +325,11 @@ impl From<crate::tenant::mgr::DeleteTimelineError> for ApiError {
     }
 }
 
-impl From<crate::tenant::delete::DeleteTenantError> for ApiError {
-    fn from(value: crate::tenant::delete::DeleteTenantError) -> Self {
-        use crate::tenant::delete::DeleteTenantError::*;
+impl From<crate::tenant::mgr::DeleteTenantError> for ApiError {
+    fn from(value: crate::tenant::mgr::DeleteTenantError) -> Self {
+        use crate::tenant::mgr::DeleteTenantError::*;
         match value {
-            Get(g) => ApiError::from(g),
-            Timeline(t) => ApiError::from(t),
             SlotError(e) => e.into(),
-            SlotUpsertError(e) => e.into(),
             Other(o) => ApiError::InternalServerError(o),
             Cancelled => ApiError::ShuttingDown,
         }
@@ -731,6 +724,8 @@ async fn get_lsn_by_timestamp_handler(
         .map_err(ApiError::BadRequest)?;
     let timestamp_pg = postgres_ffi::to_pg_timestamp(timestamp);
 
+    let with_lease = parse_query_param(&request, "with_lease")?.unwrap_or(false);
+
     let ctx = RequestContext::new(TaskKind::MgmtRequest, DownloadBehavior::Download);
 
     let timeline =
@@ -739,10 +734,15 @@ async fn get_lsn_by_timestamp_handler(
     let result = timeline
         .find_lsn_for_timestamp(timestamp_pg, &cancel, &ctx)
         .await?;
+
     #[derive(serde::Serialize, Debug)]
     struct Result {
         lsn: Lsn,
         kind: &'static str,
+        #[serde(default)]
+        #[serde(skip_serializing_if = "Option::is_none")]
+        #[serde(flatten)]
+        lease: Option<LsnLease>,
     }
     let (lsn, kind) = match result {
         LsnForTimestamp::Present(lsn) => (lsn, "present"),
@@ -750,11 +750,28 @@ async fn get_lsn_by_timestamp_handler(
         LsnForTimestamp::Past(lsn) => (lsn, "past"),
         LsnForTimestamp::NoData(lsn) => (lsn, "nodata"),
     };
-    let result = Result { lsn, kind };
+
+    let lease = if with_lease {
+        timeline
+            .make_lsn_lease(lsn, timeline.get_lsn_lease_length_for_ts(), &ctx)
+            .inspect_err(|_| {
+                warn!("fail to grant a lease to {}", lsn);
+            })
+            .ok()
+    } else {
+        None
+    };
+
+    let result = Result { lsn, kind, lease };
+    let valid_until = result
+        .lease
+        .as_ref()
+        .map(|l| humantime::format_rfc3339_millis(l.valid_until).to_string());
     tracing::info!(
         lsn=?result.lsn,
         kind=%result.kind,
         timestamp=%timestamp_raw,
+        valid_until=?valid_until,
         "lsn_by_timestamp finished"
     );
     json_response(StatusCode::OK, result)
@@ -799,58 +816,6 @@ async fn get_timestamp_of_lsn_handler(
     }
 }
 
-async fn tenant_attach_handler(
-    mut request: Request<Body>,
-    _cancel: CancellationToken,
-) -> Result<Response<Body>, ApiError> {
-    let tenant_id: TenantId = parse_request_param(&request, "tenant_id")?;
-    check_permission(&request, Some(tenant_id))?;
-
-    let maybe_body: Option<TenantAttachRequest> = json_request_or_empty_body(&mut request).await?;
-    let tenant_conf = match &maybe_body {
-        Some(request) => TenantConfOpt::try_from(&*request.config).map_err(ApiError::BadRequest)?,
-        None => TenantConfOpt::default(),
-    };
-
-    let ctx = RequestContext::new(TaskKind::MgmtRequest, DownloadBehavior::Warn);
-
-    info!("Handling tenant attach {tenant_id}");
-
-    let state = get_state(&request);
-
-    let generation = get_request_generation(state, maybe_body.as_ref().and_then(|r| r.generation))?;
-
-    let tenant_shard_id = TenantShardId::unsharded(tenant_id);
-    let shard_params = ShardParameters::default();
-    let location_conf = LocationConf::attached_single(tenant_conf, generation, &shard_params);
-
-    let tenant = state
-        .tenant_manager
-        .upsert_location(tenant_shard_id, location_conf, None, SpawnMode::Eager, &ctx)
-        .await?;
-
-    let Some(tenant) = tenant else {
-        // This should never happen: indicates a bug in upsert_location
-        return Err(ApiError::InternalServerError(anyhow::anyhow!(
-            "Upsert succeeded but didn't return tenant!"
-        )));
-    };
-
-    // We might have successfully constructed a Tenant, but it could still
-    // end up in a broken state:
-    if let TenantState::Broken {
-        reason,
-        backtrace: _,
-    } = tenant.current_state()
-    {
-        return Err(ApiError::InternalServerError(anyhow::anyhow!(
-            "Tenant state is Broken: {reason}"
-        )));
-    }
-
-    json_response(StatusCode::ACCEPTED, ())
-}
-
 async fn timeline_delete_handler(
     request: Request<Body>,
     _cancel: CancellationToken,
@@ -881,26 +846,6 @@ async fn timeline_delete_handler(
     json_response(StatusCode::ACCEPTED, ())
 }
 
-async fn tenant_detach_handler(
-    request: Request<Body>,
-    _cancel: CancellationToken,
-) -> Result<Response<Body>, ApiError> {
-    let tenant_id: TenantId = parse_request_param(&request, "tenant_id")?;
-    check_permission(&request, Some(tenant_id))?;
-    // This is a legacy API (`/location_conf` is the replacement).  It only supports unsharded tenants
-    let tenant_shard_id = TenantShardId::unsharded(tenant_id);
-
-    let state = get_state(&request);
-    let conf = state.conf;
-    state
-        .tenant_manager
-        .detach_tenant(conf, tenant_shard_id, &state.deletion_queue_client)
-        .instrument(info_span!("tenant_detach", %tenant_id, shard_id=%tenant_shard_id.shard_slug()))
-        .await?;
-
-    json_response(StatusCode::OK, ())
-}
-
 async fn tenant_reset_handler(
     request: Request<Body>,
     _cancel: CancellationToken,
@@ -940,7 +885,9 @@ async fn tenant_list_handler(
             state: state.clone(),
             current_physical_size: None,
             attachment_status: state.attachment_status(),
-            generation: (*gen).into(),
+            generation: (*gen)
+                .into()
+                .expect("Tenants are always attached with a generation"),
         })
         .collect::<Vec<TenantInfo>>();
 
@@ -988,7 +935,10 @@ async fn tenant_status(
                 state: state.clone(),
                 current_physical_size: Some(current_physical_size),
                 attachment_status: state.attachment_status(),
-                generation: tenant.generation().into(),
+                generation: tenant
+                    .generation()
+                    .into()
+                    .expect("Tenants are always attached with a generation"),
             },
             walredo: tenant.wal_redo_manager_status(),
             timelines: tenant.list_timeline_ids(),
@@ -1285,75 +1235,6 @@ pub fn html_response(status: StatusCode, data: String) -> Result<Response<Body>,
     Ok(response)
 }
 
-/// Helper for requests that may take a generation, which is mandatory
-/// when control_plane_api is set, but otherwise defaults to Generation::none()
-fn get_request_generation(state: &State, req_gen: Option<u32>) -> Result<Generation, ApiError> {
-    if state.conf.control_plane_api.is_some() {
-        req_gen
-            .map(Generation::new)
-            .ok_or(ApiError::BadRequest(anyhow!(
-                "generation attribute missing"
-            )))
-    } else {
-        // Legacy mode: all tenants operate with no generation
-        Ok(Generation::none())
-    }
-}
-
-async fn tenant_create_handler(
-    mut request: Request<Body>,
-    _cancel: CancellationToken,
-) -> Result<Response<Body>, ApiError> {
-    let request_data: TenantCreateRequest = json_request(&mut request).await?;
-    let target_tenant_id = request_data.new_tenant_id;
-    check_permission(&request, None)?;
-
-    let _timer = STORAGE_TIME_GLOBAL
-        .get_metric_with_label_values(&[StorageTimeOperation::CreateTenant.into()])
-        .expect("bug")
-        .start_timer();
-
-    let tenant_conf =
-        TenantConfOpt::try_from(&request_data.config).map_err(ApiError::BadRequest)?;
-
-    let state = get_state(&request);
-
-    let generation = get_request_generation(state, request_data.generation)?;
-
-    let ctx = RequestContext::new(TaskKind::MgmtRequest, DownloadBehavior::Warn);
-
-    let location_conf =
-        LocationConf::attached_single(tenant_conf, generation, &request_data.shard_parameters);
-
-    let new_tenant = state
-        .tenant_manager
-        .upsert_location(
-            target_tenant_id,
-            location_conf,
-            None,
-            SpawnMode::Create,
-            &ctx,
-        )
-        .await?;
-
-    let Some(new_tenant) = new_tenant else {
-        // This should never happen: indicates a bug in upsert_location
-        return Err(ApiError::InternalServerError(anyhow::anyhow!(
-            "Upsert succeeded but didn't return tenant!"
-        )));
-    };
-    // We created the tenant. Existing API semantics are that the tenant
-    // is Active when this function returns.
-    new_tenant
-        .wait_to_become_active(ACTIVE_TENANT_TIMEOUT)
-        .await?;
-
-    json_response(
-        StatusCode::CREATED,
-        TenantCreateResponse(new_tenant.tenant_shard_id().tenant_id),
-    )
-}
-
 async fn get_tenant_config_handler(
     request: Request<Body>,
     _cancel: CancellationToken,
@@ -1705,6 +1586,14 @@ async fn timeline_compact_handler(
     if Some(true) == parse_query_param::<_, bool>(&request, "force_image_layer_creation")? {
         flags |= CompactFlags::ForceImageLayerCreation;
     }
+    if Some(true) == parse_query_param::<_, bool>(&request, "enhanced_gc_bottom_most_compaction")? {
+        if !cfg!(feature = "testing") {
+            return Err(ApiError::InternalServerError(anyhow!(
+                "enhanced_gc_bottom_most_compaction is only available in testing mode"
+            )));
+        }
+        flags |= CompactFlags::EnhancedGcBottomMostCompaction;
+    }
     let wait_until_uploaded =
         parse_query_param::<_, bool>(&request, "wait_until_uploaded")?.unwrap_or(false);
 
@@ -2651,7 +2540,6 @@ pub fn make_router(
             api_handler(r, reload_auth_validation_keys_handler)
         })
         .get("/v1/tenant", |r| api_handler(r, tenant_list_handler))
-        .post("/v1/tenant", |r| api_handler(r, tenant_create_handler))
         .get("/v1/tenant/:tenant_shard_id", |r| {
             api_handler(r, tenant_status)
         })
@@ -2689,12 +2577,6 @@ pub fn make_router(
         .post("/v1/tenant/:tenant_shard_id/timeline", |r| {
             api_handler(r, timeline_create_handler)
         })
-        .post("/v1/tenant/:tenant_id/attach", |r| {
-            api_handler(r, tenant_attach_handler)
-        })
-        .post("/v1/tenant/:tenant_id/detach", |r| {
-            api_handler(r, tenant_detach_handler)
-        })
         .post("/v1/tenant/:tenant_shard_id/reset", |r| {
             api_handler(r, tenant_reset_handler)
         })

pageserver/src/lib.rs

@@ -113,11 +113,7 @@ pub async fn shutdown_pageserver(
 }
 
 /// Per-tenant configuration file.
-/// Full path: `tenants/<tenant_id>/config`.
-pub(crate) const TENANT_CONFIG_NAME: &str = "config";
-
-/// Per-tenant configuration file.
-/// Full path: `tenants/<tenant_id>/config`.
+/// Full path: `tenants/<tenant_id>/config-v1`.
 pub(crate) const TENANT_LOCATION_CONFIG_NAME: &str = "config-v1";
 
 /// Per-tenant copy of their remote heatmap, downloaded into the local

pageserver/src/metrics.rs

@@ -53,9 +53,6 @@ pub(crate) enum StorageTimeOperation {
 
     #[strum(serialize = "find gc cutoffs")]
     FindGcCutoffs,
-
-    #[strum(serialize = "create tenant")]
-    CreateTenant,
 }
 
 pub(crate) static STORAGE_TIME_SUM_PER_TIMELINE: Lazy<CounterVec> = Lazy::new(|| {
@@ -545,6 +542,15 @@ static AUX_FILE_SIZE: Lazy<IntGaugeVec> = Lazy::new(|| {
     .expect("failed to define a metric")
 });
 
+static VALID_LSN_LEASE_COUNT: Lazy<UIntGaugeVec> = Lazy::new(|| {
+    register_uint_gauge_vec!(
+        "pageserver_valid_lsn_lease_count",
+        "The number of valid leases after refreshing gc info.",
+        &["tenant_id", "shard_id", "timeline_id"],
+    )
+    .expect("failed to define a metric")
+});
+
 pub(crate) mod initial_logical_size {
     use metrics::{register_int_counter, register_int_counter_vec, IntCounter, IntCounterVec};
     use once_cell::sync::Lazy;
@@ -1436,6 +1442,46 @@ pub(crate) static LIVE_CONNECTIONS_COUNT: Lazy<IntGaugeVec> = Lazy::new(|| {
     .expect("failed to define a metric")
 });
 
+#[derive(Clone, Copy, enum_map::Enum, IntoStaticStr)]
+pub(crate) enum ComputeCommandKind {
+    PageStreamV2,
+    PageStream,
+    Basebackup,
+    GetLastRecordRlsn,
+    Fullbackup,
+    ImportBasebackup,
+    ImportWal,
+    LeaseLsn,
+    Show,
+}
+
+pub(crate) struct ComputeCommandCounters {
+    map: EnumMap<ComputeCommandKind, IntCounter>,
+}
+
+pub(crate) static COMPUTE_COMMANDS_COUNTERS: Lazy<ComputeCommandCounters> = Lazy::new(|| {
+    let inner = register_int_counter_vec!(
+        "pageserver_compute_commands",
+        "Number of compute -> pageserver commands processed",
+        &["command"]
+    )
+    .expect("failed to define a metric");
+
+    ComputeCommandCounters {
+        map: EnumMap::from_array(std::array::from_fn(|i| {
+            let command = <ComputeCommandKind as enum_map::Enum>::from_usize(i);
+            let command_str: &'static str = command.into();
+            inner.with_label_values(&[command_str])
+        })),
+    }
+});
+
+impl ComputeCommandCounters {
+    pub(crate) fn for_command(&self, command: ComputeCommandKind) -> &IntCounter {
+        &self.map[command]
+    }
+}
+
 // remote storage metrics
 
 static REMOTE_TIMELINE_CLIENT_CALLS: Lazy<IntCounterPairVec> = Lazy::new(|| {
@@ -2055,6 +2101,8 @@ pub(crate) struct TimelineMetrics {
     pub directory_entries_count_gauge: Lazy<UIntGauge, Box<dyn Send + Fn() -> UIntGauge>>,
     pub evictions: IntCounter,
     pub evictions_with_low_residence_duration: std::sync::RwLock<EvictionsWithLowResidenceDuration>,
+    /// Number of valid LSN leases.
+    pub valid_lsn_lease_count_gauge: UIntGauge,
     shutdown: std::sync::atomic::AtomicBool,
 }
 
@@ -2153,6 +2201,10 @@ impl TimelineMetrics {
         let evictions_with_low_residence_duration = evictions_with_low_residence_duration_builder
             .build(&tenant_id, &shard_id, &timeline_id);
 
+        let valid_lsn_lease_count_gauge = VALID_LSN_LEASE_COUNT
+            .get_metric_with_label_values(&[&tenant_id, &shard_id, &timeline_id])
+            .unwrap();
+
         TimelineMetrics {
             tenant_id,
             shard_id,
@@ -2175,6 +2227,7 @@ impl TimelineMetrics {
             evictions_with_low_residence_duration: std::sync::RwLock::new(
                 evictions_with_low_residence_duration,
             ),
+            valid_lsn_lease_count_gauge,
             shutdown: std::sync::atomic::AtomicBool::default(),
         }
     }
@@ -2224,6 +2277,7 @@ impl TimelineMetrics {
         }
         let _ = EVICTIONS.remove_label_values(&[tenant_id, shard_id, timeline_id]);
         let _ = AUX_FILE_SIZE.remove_label_values(&[tenant_id, shard_id, timeline_id]);
+        let _ = VALID_LSN_LEASE_COUNT.remove_label_values(&[tenant_id, shard_id, timeline_id]);
 
         self.evictions_with_low_residence_duration
             .write()
@@ -2932,4 +2986,5 @@ pub fn preinitialize_metrics() {
     Lazy::force(&RECONSTRUCT_TIME);
     Lazy::force(&tenant_throttling::TIMELINE_GET);
     Lazy::force(&BASEBACKUP_QUERY_TIME);
+    Lazy::force(&COMPUTE_COMMANDS_COUNTERS);
 }

pageserver/src/page_service.rs

@@ -55,7 +55,7 @@ use crate::basebackup::BasebackupError;
 use crate::context::{DownloadBehavior, RequestContext};
 use crate::import_datadir::import_wal_from_tar;
 use crate::metrics;
-use crate::metrics::LIVE_CONNECTIONS_COUNT;
+use crate::metrics::{ComputeCommandKind, COMPUTE_COMMANDS_COUNTERS, LIVE_CONNECTIONS_COUNT};
 use crate::pgdatadir_mapping::Version;
 use crate::span::debug_assert_current_span_has_tenant_and_timeline_id;
 use crate::span::debug_assert_current_span_has_tenant_and_timeline_id_no_shard_id;
@@ -1554,6 +1554,10 @@ where
 
             self.check_permission(Some(tenant_id))?;
 
+            COMPUTE_COMMANDS_COUNTERS
+                .for_command(ComputeCommandKind::PageStreamV2)
+                .inc();
+
             self.handle_pagerequests(
                 pgb,
                 tenant_id,
@@ -1579,6 +1583,10 @@ where
 
             self.check_permission(Some(tenant_id))?;
 
+            COMPUTE_COMMANDS_COUNTERS
+                .for_command(ComputeCommandKind::PageStream)
+                .inc();
+
             self.handle_pagerequests(
                 pgb,
                 tenant_id,
@@ -1605,6 +1613,10 @@ where
 
             self.check_permission(Some(tenant_id))?;
 
+            COMPUTE_COMMANDS_COUNTERS
+                .for_command(ComputeCommandKind::Basebackup)
+                .inc();
+
             let lsn = if let Some(lsn_str) = params.get(2) {
                 Some(
                     Lsn::from_str(lsn_str)
@@ -1662,6 +1674,11 @@ where
                 .record("timeline_id", field::display(timeline_id));
 
             self.check_permission(Some(tenant_id))?;
+
+            COMPUTE_COMMANDS_COUNTERS
+                .for_command(ComputeCommandKind::GetLastRecordRlsn)
+                .inc();
+
             async {
                 let timeline = self
                     .get_active_tenant_timeline(tenant_id, timeline_id, ShardSelector::Zero)
@@ -1723,6 +1740,10 @@ where
 
             self.check_permission(Some(tenant_id))?;
 
+            COMPUTE_COMMANDS_COUNTERS
+                .for_command(ComputeCommandKind::Fullbackup)
+                .inc();
+
             // Check that the timeline exists
             self.handle_basebackup_request(
                 pgb,
@@ -1771,6 +1792,10 @@ where
 
             self.check_permission(Some(tenant_id))?;
 
+            COMPUTE_COMMANDS_COUNTERS
+                .for_command(ComputeCommandKind::ImportBasebackup)
+                .inc();
+
             match self
                 .handle_import_basebackup(
                     pgb,
@@ -1818,6 +1843,10 @@ where
 
             self.check_permission(Some(tenant_id))?;
 
+            COMPUTE_COMMANDS_COUNTERS
+                .for_command(ComputeCommandKind::ImportWal)
+                .inc();
+
             match self
                 .handle_import_wal(pgb, tenant_id, timeline_id, start_lsn, end_lsn, ctx)
                 .await
@@ -1855,6 +1884,10 @@ where
 
             self.check_permission(Some(tenant_shard_id.tenant_id))?;
 
+            COMPUTE_COMMANDS_COUNTERS
+                .for_command(ComputeCommandKind::LeaseLsn)
+                .inc();
+
             // The caller is responsible for providing correct lsn.
             let lsn = Lsn::from_str(params[2])
                 .with_context(|| format!("Failed to parse Lsn from {}", params[2]))?;
@@ -1886,6 +1919,10 @@ where
 
             self.check_permission(Some(tenant_id))?;
 
+            COMPUTE_COMMANDS_COUNTERS
+                .for_command(ComputeCommandKind::Show)
+                .inc();
+
             let tenant = self
                 .get_active_tenant_with_timeout(
                     tenant_id,

pageserver/src/tenant.rs

@@ -55,11 +55,9 @@ use self::config::AttachedLocationConfig;
 use self::config::AttachmentMode;
 use self::config::LocationConf;
 use self::config::TenantConf;
-use self::delete::DeleteTenantFlow;
 use self::metadata::TimelineMetadata;
 use self::mgr::GetActiveTenantError;
 use self::mgr::GetTenantError;
-use self::mgr::TenantsMap;
 use self::remote_timeline_client::upload::upload_index_part;
 use self::remote_timeline_client::RemoteTimelineClient;
 use self::timeline::uninit::TimelineCreateGuard;
@@ -90,6 +88,7 @@ use crate::tenant::remote_timeline_client::MaybeDeletedIndexPart;
 use crate::tenant::remote_timeline_client::INITDB_PATH;
 use crate::tenant::storage_layer::DeltaLayer;
 use crate::tenant::storage_layer::ImageLayer;
+use crate::walredo;
 use crate::InitializationOrder;
 use std::collections::hash_map::Entry;
 use std::collections::BTreeSet;
@@ -137,7 +136,6 @@ pub mod remote_timeline_client;
 pub mod storage_layer;
 
 pub mod config;
-pub mod delete;
 pub mod mgr;
 pub mod secondary;
 pub mod tasks;
@@ -161,8 +159,6 @@ pub const TENANTS_SEGMENT_NAME: &str = "tenants";
 /// Parts of the `.neon/tenants/<tenant_id>/timelines/<timeline_id>` directory prefix.
 pub const TIMELINES_SEGMENT_NAME: &str = "timelines";
 
-pub const TENANT_DELETED_MARKER_FILE_NAME: &str = "deleted";
-
 /// References to shared objects that are passed into each tenant, such
 /// as the shared remote storage client and process initialization state.
 #[derive(Clone)]
@@ -207,7 +203,6 @@ struct TimelinePreload {
 }
 
 pub(crate) struct TenantPreload {
-    deleting: bool,
     timelines: HashMap<TimelineId, TimelinePreload>,
 }
 
@@ -218,8 +213,6 @@ pub(crate) enum SpawnMode {
     Eager,
     /// Lazy activation in the background, with the option to skip the queue if the need comes up
     Lazy,
-    /// Tenant has been created during the lifetime of this process
-    Create,
 }
 
 ///
@@ -286,8 +279,6 @@ pub struct Tenant {
     /// background warmup.
     pub(crate) activate_now_sem: tokio::sync::Semaphore,
 
-    pub(crate) delete_progress: Arc<tokio::sync::Mutex<DeleteTenantFlow>>,
-
     // Cancellation token fires when we have entered shutdown().  This is a parent of
     // Timelines' cancellation token.
     pub(crate) cancel: CancellationToken,
@@ -331,6 +322,16 @@ impl From<harness::TestRedoManager> for WalRedoManager {
 }
 
 impl WalRedoManager {
+    pub(crate) async fn shutdown(&self) {
+        match self {
+            Self::Prod(mgr) => mgr.shutdown().await,
+            #[cfg(test)]
+            Self::Test(_) => {
+                // Not applicable to test redo manager
+            }
+        }
+    }
+
     pub(crate) fn maybe_quiesce(&self, idle_timeout: Duration) {
         match self {
             Self::Prod(mgr) => mgr.maybe_quiesce(idle_timeout),
@@ -351,7 +352,7 @@ impl WalRedoManager {
         base_img: Option<(Lsn, bytes::Bytes)>,
         records: Vec<(Lsn, crate::walrecord::NeonWalRecord)>,
         pg_version: u32,
-    ) -> anyhow::Result<bytes::Bytes> {
+    ) -> Result<bytes::Bytes, walredo::Error> {
         match self {
             Self::Prod(mgr) => {
                 mgr.request_redo(key, lsn, base_img, records, pg_version)
@@ -654,10 +655,9 @@ impl Tenant {
         attached_conf: AttachedTenantConf,
         shard_identity: ShardIdentity,
         init_order: Option<InitializationOrder>,
-        tenants: &'static std::sync::RwLock<TenantsMap>,
         mode: SpawnMode,
         ctx: &RequestContext,
-    ) -> anyhow::Result<Arc<Tenant>> {
+    ) -> Arc<Tenant> {
         let wal_redo_manager = Arc::new(WalRedoManager::from(PostgresRedoManager::new(
             conf,
             tenant_shard_id,
@@ -806,9 +806,6 @@ impl Tenant {
                 };
 
                 let preload = match &mode {
-                    SpawnMode::Create => {
-                        None
-                    },
                     SpawnMode::Eager | SpawnMode::Lazy => {
                         let _preload_timer = TENANT.preload.start_timer();
                         let res = tenant_clone
@@ -828,59 +825,10 @@ impl Tenant {
                 // Remote preload is complete.
                 drop(remote_load_completion);
 
-                let pending_deletion = {
-                    match DeleteTenantFlow::should_resume_deletion(
-                        conf,
-                        preload.as_ref().map(|p| p.deleting).unwrap_or(false),
-                        &tenant_clone,
-                    )
-                    .await
-                    {
-                        Ok(should_resume_deletion) => should_resume_deletion,
-                        Err(err) => {
-                            make_broken(&tenant_clone, anyhow::anyhow!(err), BrokenVerbosity::Error);
-                            return Ok(());
-                        }
-                    }
-                };
-
-                info!("pending_deletion {}", pending_deletion.is_some());
-
-                if let Some(deletion) = pending_deletion {
-                    // as we are no longer loading, signal completion by dropping
-                    // the completion while we resume deletion
-                    drop(_completion);
-                    let background_jobs_can_start =
-                        init_order.as_ref().map(|x| &x.background_jobs_can_start);
-                    if let Some(background) = background_jobs_can_start {
-                        info!("waiting for backgound jobs barrier");
-                        background.clone().wait().await;
-                        info!("ready for backgound jobs barrier");
-                    }
-
-                    let deleted = DeleteTenantFlow::resume_from_attach(
-                        deletion,
-                        &tenant_clone,
-                        preload,
-                        tenants,
-                        &ctx,
-                    )
-                    .await;
-
-                    if let Err(e) = deleted {
-                        make_broken(&tenant_clone, anyhow::anyhow!(e), BrokenVerbosity::Error);
-                    }
-
-                    return Ok(());
-                }
-
                 // We will time the duration of the attach phase unless this is a creation (attach will do no work)
                 let attached = {
-                    let _attach_timer = match mode {
-                        SpawnMode::Create => None,
-                        SpawnMode::Eager | SpawnMode::Lazy => Some(TENANT.attach.start_timer()),
-                    };
-                    tenant_clone.attach(preload, mode, &ctx).await
+                    let _attach_timer = Some(TENANT.attach.start_timer());
+                    tenant_clone.attach(preload, &ctx).await
                 };
 
                 match attached {
@@ -911,7 +859,7 @@ impl Tenant {
             }
             .instrument(tracing::info_span!(parent: None, "attach", tenant_id=%tenant_shard_id.tenant_id, shard_id=%tenant_shard_id.shard_slug(), gen=?generation)),
         );
-        Ok(tenant)
+        tenant
     }
 
     #[instrument(skip_all)]
@@ -931,21 +879,13 @@ impl Tenant {
         )
         .await?;
 
-        let deleting = other_keys.contains(TENANT_DELETED_MARKER_FILE_NAME);
-        info!(
-            "found {} timelines, deleting={}",
-            remote_timeline_ids.len(),
-            deleting
-        );
+        info!("found {} timelines", remote_timeline_ids.len(),);
 
         for k in other_keys {
-            if k != TENANT_DELETED_MARKER_FILE_NAME {
-                warn!("Unexpected non timeline key {k}");
-            }
+            warn!("Unexpected non timeline key {k}");
         }
 
         Ok(TenantPreload {
-            deleting,
             timelines: Self::load_timeline_metadata(
                 self,
                 remote_timeline_ids,
@@ -964,22 +904,14 @@ impl Tenant {
     async fn attach(
         self: &Arc<Tenant>,
         preload: Option<TenantPreload>,
-        mode: SpawnMode,
         ctx: &RequestContext,
     ) -> anyhow::Result<()> {
         span::debug_assert_current_span_has_tenant_id();
 
         failpoint_support::sleep_millis_async!("before-attaching-tenant");
 
-        let preload = match (preload, mode) {
-            (Some(p), _) => p,
-            (None, SpawnMode::Create) => TenantPreload {
-                deleting: false,
-                timelines: HashMap::new(),
-            },
-            (None, _) => {
-                anyhow::bail!("local-only deployment is no longer supported, https://github.com/neondatabase/neon/issues/5624");
-            }
+        let Some(preload) = preload else {
+            anyhow::bail!("local-only deployment is no longer supported, https://github.com/neondatabase/neon/issues/5624");
         };
 
         let mut timelines_to_resume_deletions = vec![];
@@ -1211,30 +1143,6 @@ impl Tenant {
         .await
     }
 
-    /// Create a placeholder Tenant object for a broken tenant
-    pub fn create_broken_tenant(
-        conf: &'static PageServerConf,
-        tenant_shard_id: TenantShardId,
-        remote_storage: GenericRemoteStorage,
-        reason: String,
-    ) -> Arc<Tenant> {
-        Arc::new(Tenant::new(
-            TenantState::Broken {
-                reason,
-                backtrace: String::new(),
-            },
-            conf,
-            AttachedTenantConf::try_from(LocationConf::default()).unwrap(),
-            // Shard identity isn't meaningful for a broken tenant: it's just a placeholder
-            // to occupy the slot for this TenantShardId.
-            ShardIdentity::broken(tenant_shard_id.shard_number, tenant_shard_id.shard_count),
-            None,
-            tenant_shard_id,
-            remote_storage,
-            DeletionQueueClient::broken(),
-        ))
-    }
-
     async fn load_timeline_metadata(
         self: &Arc<Tenant>,
         timeline_ids: HashSet<TimelineId>,
@@ -1941,6 +1849,10 @@ impl Tenant {
         tracing::debug!("Waiting for tasks...");
         task_mgr::shutdown_tasks(None, Some(self.tenant_shard_id), None).await;
 
+        if let Some(walredo_mgr) = self.walredo_mgr.as_ref() {
+            walredo_mgr.shutdown().await;
+        }
+
         // Wait for any in-flight operations to complete
         self.gate.close().await;
 
@@ -2215,6 +2127,7 @@ impl Tenant {
             // Upload an index from the parent: this is partly to provide freshness for the
             // child tenants that will copy it, and partly for general ease-of-debugging: there will
             // always be a parent shard index in the same generation as we wrote the child shard index.
+            tracing::info!(timeline_id=%timeline.timeline_id, "Uploading index");
             timeline
                 .remote_client
                 .schedule_index_upload_for_file_changes()?;
@@ -2222,12 +2135,14 @@ impl Tenant {
 
             // Shut down the timeline's remote client: this means that the indices we write
             // for child shards will not be invalidated by the parent shard deleting layers.
+            tracing::info!(timeline_id=%timeline.timeline_id, "Shutting down remote storage client");
             timeline.remote_client.shutdown().await;
 
             // Download methods can still be used after shutdown, as they don't flow through the remote client's
             // queue.  In principal the RemoteTimelineClient could provide this without downloading it, but this
             // operation is rare, so it's simpler to just download it (and robustly guarantees that the index
             // we use here really is the remotely persistent one).
+            tracing::info!(timeline_id=%timeline.timeline_id, "Downloading index_part from parent");
             let result = timeline.remote_client
                 .download_index_file(&self.cancel)
                 .instrument(info_span!("download_index_file", tenant_id=%self.tenant_shard_id.tenant_id, shard_id=%self.tenant_shard_id.shard_slug(), timeline_id=%timeline.timeline_id))
@@ -2240,6 +2155,7 @@ impl Tenant {
             };
 
             for child_shard in child_shards {
+                tracing::info!(timeline_id=%timeline.timeline_id, "Uploading index_part for child {}", child_shard.to_index());
                 upload_index_part(
                     &self.remote_storage,
                     child_shard,
@@ -2554,6 +2470,10 @@ impl Tenant {
         remote_storage: GenericRemoteStorage,
         deletion_queue_client: DeletionQueueClient,
     ) -> Tenant {
+        debug_assert!(
+            !attached_conf.location.generation.is_none() || conf.control_plane_api.is_none()
+        );
+
         let (state, mut rx) = watch::channel(state);
 
         tokio::spawn(async move {
@@ -2628,7 +2548,6 @@ impl Tenant {
             cached_synthetic_tenant_size: Arc::new(AtomicU64::new(0)),
             eviction_task_tenant_state: tokio::sync::Mutex::new(EvictionTaskTenantState::default()),
             activate_now_sem: tokio::sync::Semaphore::new(0),
-            delete_progress: Arc::new(tokio::sync::Mutex::new(DeleteTenantFlow::default())),
             cancel: CancellationToken::default(),
             gate: Gate::default(),
             timeline_get_throttle: Arc::new(throttle::Throttle::new(
@@ -2645,45 +2564,22 @@ impl Tenant {
         conf: &'static PageServerConf,
         tenant_shard_id: &TenantShardId,
     ) -> anyhow::Result<LocationConf> {
-        let legacy_config_path = conf.tenant_config_path(tenant_shard_id);
         let config_path = conf.tenant_location_config_path(tenant_shard_id);
 
         if config_path.exists() {
             // New-style config takes precedence
             let deserialized = Self::read_config(&config_path)?;
             Ok(toml_edit::de::from_document::<LocationConf>(deserialized)?)
-        } else if legacy_config_path.exists() {
-            // Upgrade path: found an old-style configuration only
-            let deserialized = Self::read_config(&legacy_config_path)?;
-
-            let mut tenant_conf = TenantConfOpt::default();
-            for (key, item) in deserialized.iter() {
-                match key {
-                    "tenant_config" => {
-                        tenant_conf = TenantConfOpt::try_from(item.to_owned()).context(format!("Failed to parse config from file '{legacy_config_path}' as pageserver config"))?;
-                    }
-                    _ => bail!(
-                        "config file {legacy_config_path} has unrecognized pageserver option '{key}'"
-                    ),
-                }
-            }
-
-            // Legacy configs are implicitly in attached state, and do not support sharding
-            Ok(LocationConf::attached_single(
-                tenant_conf,
-                Generation::none(),
-                &models::ShardParameters::default(),
-            ))
         } else {
-            // FIXME If the config file is not found, assume that we're attaching
-            // a detached tenant and config is passed via attach command.
-            // https://github.com/neondatabase/neon/issues/1555
-            // OR: we're loading after incomplete deletion that managed to remove config.
-            info!(
-                "tenant config not found in {} or {}",
-                config_path, legacy_config_path
-            );
-            Ok(LocationConf::default())
+            // The config should almost always exist for a tenant directory:
+            //  - When attaching a tenant, the config is the first thing we write
+            //  - When detaching a tenant, we atomically move the directory to a tmp location
+            //    before deleting contents.
+            //
+            // The very rare edge case that can result in a missing config is if we crash during attach
+            // between creating directory and writing config.  Callers should handle that as if the
+            // directory didn't exist.
+            anyhow::bail!("tenant config not found in {}", config_path);
         }
     }
 
@@ -2705,47 +2601,17 @@ impl Tenant {
         tenant_shard_id: &TenantShardId,
         location_conf: &LocationConf,
     ) -> anyhow::Result<()> {
-        let legacy_config_path = conf.tenant_config_path(tenant_shard_id);
         let config_path = conf.tenant_location_config_path(tenant_shard_id);
 
-        Self::persist_tenant_config_at(
-            tenant_shard_id,
-            &config_path,
-            &legacy_config_path,
-            location_conf,
-        )
-        .await
+        Self::persist_tenant_config_at(tenant_shard_id, &config_path, location_conf).await
     }
 
     #[tracing::instrument(skip_all, fields(tenant_id=%tenant_shard_id.tenant_id, shard_id=%tenant_shard_id.shard_slug()))]
     pub(super) async fn persist_tenant_config_at(
         tenant_shard_id: &TenantShardId,
         config_path: &Utf8Path,
-        legacy_config_path: &Utf8Path,
         location_conf: &LocationConf,
     ) -> anyhow::Result<()> {
-        if let LocationMode::Attached(attach_conf) = &location_conf.mode {
-            // The modern-style LocationConf config file requires a generation to be set. In case someone
-            // is running a pageserver without the infrastructure to set generations, write out the legacy-style
-            // config file that only contains TenantConf.
-            //
-            // This will eventually be removed in https://github.com/neondatabase/neon/issues/5388
-
-            if attach_conf.generation.is_none() {
-                tracing::info!(
-                    "Running without generations, writing legacy-style tenant config file"
-                );
-                Self::persist_tenant_config_legacy(
-                    tenant_shard_id,
-                    legacy_config_path,
-                    &location_conf.tenant_conf,
-                )
-                .await?;
-
-                return Ok(());
-            }
-        }
-
         debug!("persisting tenantconf to {config_path}");
 
         let mut conf_content = r#"# This file contains a specific per-tenant's config.
@@ -2772,37 +2638,6 @@ impl Tenant {
         Ok(())
     }
 
-    #[tracing::instrument(skip_all, fields(tenant_id=%tenant_shard_id.tenant_id, shard_id=%tenant_shard_id.shard_slug()))]
-    async fn persist_tenant_config_legacy(
-        tenant_shard_id: &TenantShardId,
-        target_config_path: &Utf8Path,
-        tenant_conf: &TenantConfOpt,
-    ) -> anyhow::Result<()> {
-        debug!("persisting tenantconf to {target_config_path}");
-
-        let mut conf_content = r#"# This file contains a specific per-tenant's config.
-#  It is read in case of pageserver restart.
-
-[tenant_config]
-"#
-        .to_string();
-
-        // Convert the config to a toml file.
-        conf_content += &toml_edit::ser::to_string(&tenant_conf)?;
-
-        let temp_path = path_with_suffix_extension(target_config_path, TEMP_FILE_SUFFIX);
-
-        let tenant_shard_id = *tenant_shard_id;
-        let target_config_path = target_config_path.to_owned();
-        let conf_content = conf_content.into_bytes();
-        VirtualFile::crashsafe_overwrite(target_config_path.clone(), temp_path, conf_content)
-            .await
-            .with_context(|| {
-                format!("write tenant {tenant_shard_id} config to {target_config_path}")
-            })?;
-        Ok(())
-    }
-
     //
     // How garbage collection works:
     //
@@ -3021,6 +2856,11 @@ impl Tenant {
                 let now = SystemTime::now();
                 target.leases.retain(|_, lease| !lease.is_expired(&now));
 
+                timeline
+                    .metrics
+                    .valid_lsn_lease_count_gauge
+                    .set(target.leases.len() as u64);
+
                 match gc_cutoffs.remove(&timeline.timeline_id) {
                     Some(cutoffs) => {
                         target.retain_lsns = branchpoints;
@@ -3906,7 +3746,9 @@ pub(crate) mod harness {
             let remote_fs_dir = conf.workdir.join("localfs");
             std::fs::create_dir_all(&remote_fs_dir).unwrap();
             let config = RemoteStorageConfig {
-                storage: RemoteStorageKind::LocalFs(remote_fs_dir.clone()),
+                storage: RemoteStorageKind::LocalFs {
+                    local_path: remote_fs_dir.clone(),
+                },
                 timeout: RemoteStorageConfig::DEFAULT_TIMEOUT,
             };
             let remote_storage = GenericRemoteStorage::from_config(&config).unwrap();
@@ -3984,7 +3826,7 @@ pub(crate) mod harness {
             let preload = tenant
                 .preload(&self.remote_storage, CancellationToken::new())
                 .await?;
-            tenant.attach(Some(preload), SpawnMode::Eager, ctx).await?;
+            tenant.attach(Some(preload), ctx).await?;
 
             tenant.state.send_replace(TenantState::Active);
             for timeline in tenant.timelines.lock().unwrap().values() {
@@ -4012,7 +3854,7 @@ pub(crate) mod harness {
             base_img: Option<(Lsn, Bytes)>,
             records: Vec<(Lsn, NeonWalRecord)>,
             _pg_version: u32,
-        ) -> anyhow::Result<Bytes> {
+        ) -> Result<Bytes, walredo::Error> {
             let records_neon = records.iter().all(|r| apply_neon::can_apply_in_neon(&r.1));
             if records_neon {
                 // For Neon wal records, we can decode without spawning postgres, so do so.
@@ -4066,6 +3908,7 @@ mod tests {
     use storage_layer::PersistentLayerKey;
     use tests::storage_layer::ValuesReconstructState;
     use tests::timeline::{GetVectoredError, ShutdownMode};
+    use timeline::GcInfo;
     use utils::bin_ser::BeSer;
     use utils::id::TenantId;
 
@@ -6421,7 +6264,7 @@ mod tests {
 
     #[tokio::test]
     async fn test_vectored_missing_metadata_key_reads() -> anyhow::Result<()> {
-        let harness = TenantHarness::create("test_vectored_missing_data_key_reads")?;
+        let harness = TenantHarness::create("test_vectored_missing_metadata_key_reads")?;
         let (tenant, ctx) = harness.load().await;
 
         let base_key = Key::from_hex("620000000033333333444444445500000000").unwrap();
@@ -6743,49 +6586,48 @@ mod tests {
 
         // img layer at 0x10
         let img_layer = (0..10)
-            .map(|id| (get_key(id), test_img(&format!("value {id}@0x10"))))
+            .map(|id| (get_key(id), Bytes::from(format!("value {id}@0x10"))))
             .collect_vec();
 
         let delta1 = vec![
-            // TODO: we should test a real delta record here, which requires us to add a variant of NeonWalRecord for testing purpose.
             (
                 get_key(1),
                 Lsn(0x20),
-                Value::Image(test_img("value 1@0x20")),
+                Value::Image(Bytes::from("value 1@0x20")),
             ),
             (
                 get_key(2),
                 Lsn(0x30),
-                Value::Image(test_img("value 2@0x30")),
+                Value::Image(Bytes::from("value 2@0x30")),
             ),
             (
                 get_key(3),
                 Lsn(0x40),
-                Value::Image(test_img("value 3@0x40")),
+                Value::Image(Bytes::from("value 3@0x40")),
             ),
         ];
         let delta2 = vec![
             (
                 get_key(5),
                 Lsn(0x20),
-                Value::Image(test_img("value 5@0x20")),
+                Value::Image(Bytes::from("value 5@0x20")),
             ),
             (
                 get_key(6),
                 Lsn(0x20),
-                Value::Image(test_img("value 6@0x20")),
+                Value::Image(Bytes::from("value 6@0x20")),
             ),
         ];
         let delta3 = vec![
             (
                 get_key(8),
                 Lsn(0x40),
-                Value::Image(test_img("value 8@0x40")),
+                Value::Image(Bytes::from("value 8@0x40")),
             ),
             (
                 get_key(9),
                 Lsn(0x40),
-                Value::Image(test_img("value 9@0x40")),
+                Value::Image(Bytes::from("value 9@0x40")),
             ),
         ];
 
@@ -6807,9 +6649,42 @@ mod tests {
             guard.cutoffs.horizon = Lsn(0x30);
         }
 
+        let expected_result = [
+            Bytes::from_static(b"value 0@0x10"),
+            Bytes::from_static(b"value 1@0x20"),
+            Bytes::from_static(b"value 2@0x30"),
+            Bytes::from_static(b"value 3@0x40"),
+            Bytes::from_static(b"value 4@0x10"),
+            Bytes::from_static(b"value 5@0x20"),
+            Bytes::from_static(b"value 6@0x20"),
+            Bytes::from_static(b"value 7@0x10"),
+            Bytes::from_static(b"value 8@0x40"),
+            Bytes::from_static(b"value 9@0x40"),
+        ];
+
+        for (idx, expected) in expected_result.iter().enumerate() {
+            assert_eq!(
+                tline
+                    .get(get_key(idx as u32), Lsn(0x50), &ctx)
+                    .await
+                    .unwrap(),
+                expected
+            );
+        }
+
         let cancel = CancellationToken::new();
         tline.compact_with_gc(&cancel, &ctx).await.unwrap();
 
+        for (idx, expected) in expected_result.iter().enumerate() {
+            assert_eq!(
+                tline
+                    .get(get_key(idx as u32), Lsn(0x50), &ctx)
+                    .await
+                    .unwrap(),
+                expected
+            );
+        }
+
         // Check if the image layer at the GC horizon contains exactly what we want
         let image_at_gc_horizon = tline
             .inspect_image_layers(Lsn(0x30), &ctx)
@@ -6820,14 +6695,22 @@ mod tests {
             .collect::<Vec<_>>();
 
         assert_eq!(image_at_gc_horizon.len(), 10);
-        let expected_lsn = [0x10, 0x20, 0x30, 0x10, 0x10, 0x20, 0x20, 0x10, 0x10, 0x10];
+        let expected_result = [
+            Bytes::from_static(b"value 0@0x10"),
+            Bytes::from_static(b"value 1@0x20"),
+            Bytes::from_static(b"value 2@0x30"),
+            Bytes::from_static(b"value 3@0x10"),
+            Bytes::from_static(b"value 4@0x10"),
+            Bytes::from_static(b"value 5@0x20"),
+            Bytes::from_static(b"value 6@0x20"),
+            Bytes::from_static(b"value 7@0x10"),
+            Bytes::from_static(b"value 8@0x10"),
+            Bytes::from_static(b"value 9@0x10"),
+        ];
         for idx in 0..10 {
             assert_eq!(
                 image_at_gc_horizon[idx],
-                (
-                    get_key(idx as u32),
-                    test_img(&format!("value {idx}@{:#x}", expected_lsn[idx]))
-                )
+                (get_key(idx as u32), expected_result[idx].clone())
             );
         }
 
@@ -6860,7 +6743,7 @@ mod tests {
                 },
                 // The delta layer that is cut in the middle
                 PersistentLayerKey {
-                    key_range: Key::MIN..get_key(9),
+                    key_range: get_key(3)..get_key(4),
                     lsn_range: Lsn(0x30)..Lsn(0x41),
                     is_delta: true
                 },
@@ -6945,6 +6828,9 @@ mod tests {
             tline.get(get_key(2), Lsn(0x50), &ctx).await?,
             Bytes::from_static(b"0x10,0x20,0x30")
         );
+
+        // Need to remove the limit of "Neon WAL redo requires base image".
+
         // assert_eq!(tline.get(get_key(3), Lsn(0x50), &ctx).await?, Bytes::new());
         // assert_eq!(tline.get(get_key(4), Lsn(0x50), &ctx).await?, Bytes::new());
 
@@ -7039,4 +6925,174 @@ mod tests {
 
         Ok(())
     }
+
+    #[tokio::test]
+    async fn test_simple_bottom_most_compaction_deltas() -> anyhow::Result<()> {
+        let harness = TenantHarness::create("test_simple_bottom_most_compaction_deltas")?;
+        let (tenant, ctx) = harness.load().await;
+
+        fn get_key(id: u32) -> Key {
+            // using aux key here b/c they are guaranteed to be inside `collect_keyspace`.
+            let mut key = Key::from_hex("620000000033333333444444445500000000").unwrap();
+            key.field6 = id;
+            key
+        }
+
+        // We create one bottom-most image layer, a delta layer D1 crossing the GC horizon, D2 below the horizon, and D3 above the horizon.
+        //
+        //  | D1 |                       | D3 |
+        // -|    |-- gc horizon -----------------
+        //  |    |                | D2 |
+        // --------- img layer ------------------
+        //
+        // What we should expact from this compaction is:
+        //  | Part of D1 |               | D3 |
+        // --------- img layer with D1+D2 at GC horizon------------------
+
+        // img layer at 0x10
+        let img_layer = (0..10)
+            .map(|id| (get_key(id), Bytes::from(format!("value {id}@0x10"))))
+            .collect_vec();
+
+        let delta1 = vec![
+            (
+                get_key(1),
+                Lsn(0x20),
+                Value::WalRecord(NeonWalRecord::wal_append("@0x20")),
+            ),
+            (
+                get_key(2),
+                Lsn(0x30),
+                Value::WalRecord(NeonWalRecord::wal_append("@0x30")),
+            ),
+            (
+                get_key(3),
+                Lsn(0x28),
+                Value::WalRecord(NeonWalRecord::wal_append("@0x28")),
+            ),
+            (
+                get_key(3),
+                Lsn(0x30),
+                Value::WalRecord(NeonWalRecord::wal_append("@0x30")),
+            ),
+            (
+                get_key(3),
+                Lsn(0x40),
+                Value::WalRecord(NeonWalRecord::wal_append("@0x40")),
+            ),
+        ];
+        let delta2 = vec![
+            (
+                get_key(5),
+                Lsn(0x20),
+                Value::WalRecord(NeonWalRecord::wal_append("@0x20")),
+            ),
+            (
+                get_key(6),
+                Lsn(0x20),
+                Value::WalRecord(NeonWalRecord::wal_append("@0x20")),
+            ),
+        ];
+        let delta3 = vec![
+            (
+                get_key(8),
+                Lsn(0x40),
+                Value::WalRecord(NeonWalRecord::wal_append("@0x40")),
+            ),
+            (
+                get_key(9),
+                Lsn(0x40),
+                Value::WalRecord(NeonWalRecord::wal_append("@0x40")),
+            ),
+        ];
+
+        let tline = tenant
+            .create_test_timeline_with_layers(
+                TIMELINE_ID,
+                Lsn(0x10),
+                DEFAULT_PG_VERSION,
+                &ctx,
+                vec![delta1, delta2, delta3], // delta layers
+                vec![(Lsn(0x10), img_layer)], // image layers
+                Lsn(0x50),
+            )
+            .await?;
+        {
+            // Update GC info
+            let mut guard = tline.gc_info.write().unwrap();
+            *guard = GcInfo {
+                retain_lsns: vec![],
+                cutoffs: GcCutoffs {
+                    pitr: Lsn(0x30),
+                    horizon: Lsn(0x30),
+                },
+                leases: Default::default(),
+            };
+        }
+
+        let expected_result = [
+            Bytes::from_static(b"value 0@0x10"),
+            Bytes::from_static(b"value 1@0x10@0x20"),
+            Bytes::from_static(b"value 2@0x10@0x30"),
+            Bytes::from_static(b"value 3@0x10@0x28@0x30@0x40"),
+            Bytes::from_static(b"value 4@0x10"),
+            Bytes::from_static(b"value 5@0x10@0x20"),
+            Bytes::from_static(b"value 6@0x10@0x20"),
+            Bytes::from_static(b"value 7@0x10"),
+            Bytes::from_static(b"value 8@0x10@0x40"),
+            Bytes::from_static(b"value 9@0x10@0x40"),
+        ];
+
+        let expected_result_at_gc_horizon = [
+            Bytes::from_static(b"value 0@0x10"),
+            Bytes::from_static(b"value 1@0x10@0x20"),
+            Bytes::from_static(b"value 2@0x10@0x30"),
+            Bytes::from_static(b"value 3@0x10@0x28@0x30"),
+            Bytes::from_static(b"value 4@0x10"),
+            Bytes::from_static(b"value 5@0x10@0x20"),
+            Bytes::from_static(b"value 6@0x10@0x20"),
+            Bytes::from_static(b"value 7@0x10"),
+            Bytes::from_static(b"value 8@0x10"),
+            Bytes::from_static(b"value 9@0x10"),
+        ];
+
+        for idx in 0..10 {
+            assert_eq!(
+                tline
+                    .get(get_key(idx as u32), Lsn(0x50), &ctx)
+                    .await
+                    .unwrap(),
+                &expected_result[idx]
+            );
+            assert_eq!(
+                tline
+                    .get(get_key(idx as u32), Lsn(0x30), &ctx)
+                    .await
+                    .unwrap(),
+                &expected_result_at_gc_horizon[idx]
+            );
+        }
+
+        let cancel = CancellationToken::new();
+        tline.compact_with_gc(&cancel, &ctx).await.unwrap();
+
+        for idx in 0..10 {
+            assert_eq!(
+                tline
+                    .get(get_key(idx as u32), Lsn(0x50), &ctx)
+                    .await
+                    .unwrap(),
+                &expected_result[idx]
+            );
+            assert_eq!(
+                tline
+                    .get(get_key(idx as u32), Lsn(0x30), &ctx)
+                    .await
+                    .unwrap(),
+                &expected_result_at_gc_horizon[idx]
+            );
+        }
+
+        Ok(())
+    }
 }

pageserver/src/tenant/blob_io.rs

@@ -127,11 +127,11 @@ impl<const BUFFERED: bool> BlobWriter<BUFFERED> {
     /// You need to make sure that the internal buffer is empty, otherwise
     /// data will be written in wrong order.
     #[inline(always)]
-    async fn write_all_unbuffered<B: BoundedBuf<Buf = Buf>, Buf: IoBuf + Send>(
+    async fn write_all_unbuffered<Buf: IoBuf + Send>(
         &mut self,
-        src_buf: B,
+        src_buf: Slice<Buf>,
         ctx: &RequestContext,
-    ) -> (B::Buf, Result<(), Error>) {
+    ) -> (Slice<Buf>, Result<(), Error>) {
         let (src_buf, res) = self.inner.write_all(src_buf, ctx).await;
         let nbytes = match res {
             Ok(nbytes) => nbytes,
@@ -145,8 +145,9 @@ impl<const BUFFERED: bool> BlobWriter<BUFFERED> {
     /// Flushes the internal buffer to the underlying `VirtualFile`.
     pub async fn flush_buffer(&mut self, ctx: &RequestContext) -> Result<(), Error> {
         let buf = std::mem::take(&mut self.buf);
-        let (mut buf, res) = self.inner.write_all(buf, ctx).await;
+        let (buf, res) = self.inner.write_all(buf.slice_full(), ctx).await;
         res?;
+        let mut buf = Slice::into_inner(buf);
         buf.clear();
         self.buf = buf;
         Ok(())
@@ -163,11 +164,20 @@ impl<const BUFFERED: bool> BlobWriter<BUFFERED> {
     }
 
     /// Internal, possibly buffered, write function
-    async fn write_all<B: BoundedBuf<Buf = Buf>, Buf: IoBuf + Send>(
+    async fn write_all<Buf: IoBuf + Send>(
         &mut self,
-        src_buf: B,
+        src_buf: Slice<Buf>,
         ctx: &RequestContext,
-    ) -> (B::Buf, Result<(), Error>) {
+    ) -> (Slice<Buf>, Result<(), Error>) {
+        let orig_bounds = src_buf.bounds();
+
+        macro_rules! return_orig_bounds {
+            ($buf:expr, $val:expr) => {{
+                let buf = $buf.into_inner();
+                return (buf.slice(orig_bounds), $val);
+            }};
+        }
+
         if !BUFFERED {
             assert!(self.buf.is_empty());
             return self.write_all_unbuffered(src_buf, ctx).await;
@@ -175,7 +185,7 @@ impl<const BUFFERED: bool> BlobWriter<BUFFERED> {
         let remaining = Self::CAPACITY - self.buf.len();
         let src_buf_len = src_buf.bytes_init();
         if src_buf_len == 0 {
-            return (Slice::into_inner(src_buf.slice_full()), Ok(()));
+            return (src_buf, Ok(()));
         }
         let mut src_buf = src_buf.slice(0..src_buf_len);
         // First try to copy as much as we can into the buffer
@@ -186,7 +196,7 @@ impl<const BUFFERED: bool> BlobWriter<BUFFERED> {
         // Then, if the buffer is full, flush it out
         if self.buf.len() == Self::CAPACITY {
             if let Err(e) = self.flush_buffer(ctx).await {
-                return (Slice::into_inner(src_buf), Err(e));
+                return_orig_bounds!(src_buf, Err(e));
             }
         }
         // Finally, write the tail of src_buf:
@@ -199,27 +209,27 @@ impl<const BUFFERED: bool> BlobWriter<BUFFERED> {
                 let copied = self.write_into_buffer(&src_buf);
                 // We just verified above that src_buf fits into our internal buffer.
                 assert_eq!(copied, src_buf.len());
-                Slice::into_inner(src_buf)
+                src_buf
             } else {
                 let (src_buf, res) = self.write_all_unbuffered(src_buf, ctx).await;
                 if let Err(e) = res {
-                    return (src_buf, Err(e));
+                    return_orig_bounds!(src_buf, Err(e));
                 }
                 src_buf
             }
         } else {
-            Slice::into_inner(src_buf)
+            src_buf
         };
-        (src_buf, Ok(()))
+        return_orig_bounds!(src_buf, Ok(()));
     }
 
     /// Write a blob of data. Returns the offset that it was written to,
     /// which can be used to retrieve the data later.
-    pub async fn write_blob<B: BoundedBuf<Buf = Buf>, Buf: IoBuf + Send>(
+    pub async fn write_blob<Buf: IoBuf + Send>(
         &mut self,
-        srcbuf: B,
+        srcbuf: Slice<Buf>,
         ctx: &RequestContext,
-    ) -> (B::Buf, Result<u64, Error>) {
+    ) -> (Slice<Buf>, Result<u64, Error>) {
         let offset = self.offset;
 
         let len = srcbuf.bytes_init();
@@ -230,12 +240,12 @@ impl<const BUFFERED: bool> BlobWriter<BUFFERED> {
             if len < 128 {
                 // Short blob. Write a 1-byte length header
                 io_buf.put_u8(len as u8);
-                self.write_all(io_buf, ctx).await
+                self.write_all(io_buf.slice_full(), ctx).await
             } else {
                 // Write a 4-byte length header
                 if len > 0x7fff_ffff {
                     return (
-                        io_buf,
+                        io_buf.slice_full(),
                         Err(Error::new(
                             ErrorKind::Other,
                             format!("blob too large ({len} bytes)"),
@@ -248,14 +258,14 @@ impl<const BUFFERED: bool> BlobWriter<BUFFERED> {
                 let mut len_buf = (len as u32).to_be_bytes();
                 len_buf[0] |= 0x80;
                 io_buf.extend_from_slice(&len_buf[..]);
-                self.write_all(io_buf, ctx).await
+                self.write_all(io_buf.slice_full(), ctx).await
             }
         }
         .await;
-        self.io_buf = Some(io_buf);
+        self.io_buf = Some(io_buf.into_inner());
         match hdr_res {
             Ok(_) => (),
-            Err(e) => return (Slice::into_inner(srcbuf.slice(..)), Err(e)),
+            Err(e) => return (srcbuf, Err(e)),
         }
         let (srcbuf, res) = self.write_all(srcbuf, ctx).await;
         (srcbuf, res.map(|_| offset))
@@ -305,13 +315,13 @@ mod tests {
             let file = VirtualFile::create(pathbuf.as_path(), &ctx).await?;
             let mut wtr = BlobWriter::<BUFFERED>::new(file, 0);
             for blob in blobs.iter() {
-                let (_, res) = wtr.write_blob(blob.clone(), &ctx).await;
+                let (_, res) = wtr.write_blob(blob.clone().slice_full(), &ctx).await;
                 let offs = res?;
                 offsets.push(offs);
             }
             // Write out one page worth of zeros so that we can
             // read again with read_blk
-            let (_, res) = wtr.write_blob(vec![0; PAGE_SZ], &ctx).await;
+            let (_, res) = wtr.write_blob(vec![0; PAGE_SZ].slice_full(), &ctx).await;
             let offs = res?;
             println!("Writing final blob at offs={offs}");
             wtr.flush_buffer(&ctx).await?;

pageserver/src/tenant/block_io.rs

@@ -160,6 +160,7 @@ impl<'a> BlockCursor<'a> {
 ///
 /// The file is assumed to be immutable. This doesn't provide any functions
 /// for modifying the file, nor for invalidating the cache if it is modified.
+#[derive(Clone)]
 pub struct FileBlockReader<'a> {
     pub file: &'a VirtualFile,
 

pageserver/src/tenant/config.rs

@@ -281,22 +281,6 @@ impl LocationConf {
     }
 }
 
-impl Default for LocationConf {
-    // TODO: this should be removed once tenant loading can guarantee that we are never
-    // loading from a directory without a configuration.
-    // => tech debt since https://github.com/neondatabase/neon/issues/1555
-    fn default() -> Self {
-        Self {
-            mode: LocationMode::Attached(AttachedLocationConfig {
-                generation: Generation::none(),
-                attach_mode: AttachmentMode::Single,
-            }),
-            tenant_conf: TenantConfOpt::default(),
-            shard: ShardIdentity::unsharded(),
-        }
-    }
-}
-
 /// A tenant's calcuated configuration, which is the result of merging a
 /// tenant's TenantConfOpt with the global TenantConf from PageServerConf.
 ///

pageserver/src/tenant/delete.rs

@@ -1,426 +0,0 @@
-use std::sync::Arc;
-
-use anyhow::Context;
-use camino::{Utf8Path, Utf8PathBuf};
-use pageserver_api::{models::TenantState, shard::TenantShardId};
-use remote_storage::{GenericRemoteStorage, RemotePath, TimeoutOrCancel};
-use tokio::sync::OwnedMutexGuard;
-use tokio_util::sync::CancellationToken;
-use tracing::{error, Instrument};
-
-use utils::{backoff, completion, crashsafe, fs_ext, id::TimelineId, pausable_failpoint};
-
-use crate::{
-    config::PageServerConf,
-    context::RequestContext,
-    task_mgr::{self},
-    tenant::{
-        mgr::{TenantSlot, TenantsMapRemoveResult},
-        remote_timeline_client::remote_heatmap_path,
-    },
-};
-
-use super::{
-    mgr::{GetTenantError, TenantSlotError, TenantSlotUpsertError, TenantsMap},
-    remote_timeline_client::{FAILED_REMOTE_OP_RETRIES, FAILED_UPLOAD_WARN_THRESHOLD},
-    timeline::delete::DeleteTimelineFlow,
-    tree_sort_timelines, DeleteTimelineError, Tenant, TenantPreload,
-};
-
-#[derive(Debug, thiserror::Error)]
-pub(crate) enum DeleteTenantError {
-    #[error("GetTenant {0}")]
-    Get(#[from] GetTenantError),
-
-    #[error("Tenant map slot error {0}")]
-    SlotError(#[from] TenantSlotError),
-
-    #[error("Tenant map slot upsert error {0}")]
-    SlotUpsertError(#[from] TenantSlotUpsertError),
-
-    #[error("Timeline {0}")]
-    Timeline(#[from] DeleteTimelineError),
-
-    #[error("Cancelled")]
-    Cancelled,
-
-    #[error(transparent)]
-    Other(#[from] anyhow::Error),
-}
-
-type DeletionGuard = tokio::sync::OwnedMutexGuard<DeleteTenantFlow>;
-
-fn remote_tenant_delete_mark_path(
-    conf: &PageServerConf,
-    tenant_shard_id: &TenantShardId,
-) -> anyhow::Result<RemotePath> {
-    let tenant_remote_path = conf
-        .tenant_path(tenant_shard_id)
-        .strip_prefix(&conf.workdir)
-        .context("Failed to strip workdir prefix")
-        .and_then(RemotePath::new)
-        .context("tenant path")?;
-    Ok(tenant_remote_path.join(Utf8Path::new("timelines/deleted")))
-}
-
-async fn schedule_ordered_timeline_deletions(
-    tenant: &Arc<Tenant>,
-) -> Result<Vec<(Arc<tokio::sync::Mutex<DeleteTimelineFlow>>, TimelineId)>, DeleteTenantError> {
-    // Tenant is stopping at this point. We know it will be deleted.
-    // No new timelines should be created.
-    // Tree sort timelines to delete from leafs to the root.
-    // NOTE: by calling clone we release the mutex which creates a possibility for a race: pending deletion
-    // can complete and remove timeline from the map in between our call to clone
-    // and `DeleteTimelineFlow::run`, so `run` wont find timeline in `timelines` map.
-    // timelines.lock is currently synchronous so we cant hold it across await point.
-    // So just ignore NotFound error if we get it from `run`.
-    // Beware: in case it becomes async and we try to hold it here, `run` also locks it, which can create a deadlock.
-    let timelines = tenant.timelines.lock().unwrap().clone();
-    let sorted =
-        tree_sort_timelines(timelines, |t| t.get_ancestor_timeline_id()).context("tree sort")?;
-
-    let mut already_running_deletions = vec![];
-
-    for (timeline_id, _) in sorted.into_iter().rev() {
-        let span = tracing::info_span!("timeline_delete", %timeline_id);
-        let res = DeleteTimelineFlow::run(tenant, timeline_id, true)
-            .instrument(span)
-            .await;
-        if let Err(e) = res {
-            match e {
-                DeleteTimelineError::NotFound => {
-                    // Timeline deletion finished after call to clone above but before call
-                    // to `DeleteTimelineFlow::run` and removed timeline from the map.
-                    continue;
-                }
-                DeleteTimelineError::AlreadyInProgress(guard) => {
-                    already_running_deletions.push((guard, timeline_id));
-                    continue;
-                }
-                e => return Err(DeleteTenantError::Timeline(e)),
-            }
-        }
-    }
-
-    Ok(already_running_deletions)
-}
-
-async fn ensure_timelines_dir_empty(timelines_path: &Utf8Path) -> Result<(), DeleteTenantError> {
-    // Assert timelines dir is empty.
-    if !fs_ext::is_directory_empty(timelines_path).await? {
-        // Display first 10 items in directory
-        let list = fs_ext::list_dir(timelines_path).await.context("list_dir")?;
-        let list = &list.into_iter().take(10).collect::<Vec<_>>();
-        return Err(DeleteTenantError::Other(anyhow::anyhow!(
-            "Timelines directory is not empty after all timelines deletion: {list:?}"
-        )));
-    }
-
-    Ok(())
-}
-
-async fn remove_tenant_remote_delete_mark(
-    conf: &PageServerConf,
-    remote_storage: &GenericRemoteStorage,
-    tenant_shard_id: &TenantShardId,
-    cancel: &CancellationToken,
-) -> Result<(), DeleteTenantError> {
-    let path = remote_tenant_delete_mark_path(conf, tenant_shard_id)?;
-    backoff::retry(
-        || async { remote_storage.delete(&path, cancel).await },
-        TimeoutOrCancel::caused_by_cancel,
-        FAILED_UPLOAD_WARN_THRESHOLD,
-        FAILED_REMOTE_OP_RETRIES,
-        "remove_tenant_remote_delete_mark",
-        cancel,
-    )
-    .await
-    .ok_or_else(|| anyhow::Error::new(TimeoutOrCancel::Cancel))
-    .and_then(|x| x)
-    .context("remove_tenant_remote_delete_mark")?;
-    Ok(())
-}
-
-// Cleanup fs traces: tenant config, timelines dir local delete mark, tenant dir
-async fn cleanup_remaining_fs_traces(
-    conf: &PageServerConf,
-    tenant_shard_id: &TenantShardId,
-) -> Result<(), DeleteTenantError> {
-    let rm = |p: Utf8PathBuf, is_dir: bool| async move {
-        if is_dir {
-            tokio::fs::remove_dir(&p).await
-        } else {
-            tokio::fs::remove_file(&p).await
-        }
-        .or_else(fs_ext::ignore_not_found)
-        .with_context(|| format!("failed to delete {p}"))
-    };
-
-    rm(conf.tenant_config_path(tenant_shard_id), false).await?;
-    rm(conf.tenant_location_config_path(tenant_shard_id), false).await?;
-
-    fail::fail_point!("tenant-delete-before-remove-timelines-dir", |_| {
-        Err(anyhow::anyhow!(
-            "failpoint: tenant-delete-before-remove-timelines-dir"
-        ))?
-    });
-
-    rm(conf.timelines_path(tenant_shard_id), true).await?;
-
-    fail::fail_point!("tenant-delete-before-remove-deleted-mark", |_| {
-        Err(anyhow::anyhow!(
-            "failpoint: tenant-delete-before-remove-deleted-mark"
-        ))?
-    });
-
-    // Make sure previous deletions are ordered before mark removal.
-    // Otherwise there is no guarantee that they reach the disk before mark deletion.
-    // So its possible for mark to reach disk first and for other deletions
-    // to be reordered later and thus missed if a crash occurs.
-    // Note that we dont need to sync after mark file is removed
-    // because we can tolerate the case when mark file reappears on startup.
-    let tenant_path = &conf.tenant_path(tenant_shard_id);
-    if tenant_path.exists() {
-        crashsafe::fsync_async(&conf.tenant_path(tenant_shard_id))
-            .await
-            .context("fsync_pre_mark_remove")?;
-    }
-
-    rm(conf.tenant_deleted_mark_file_path(tenant_shard_id), false).await?;
-
-    rm(conf.tenant_heatmap_path(tenant_shard_id), false).await?;
-
-    fail::fail_point!("tenant-delete-before-remove-tenant-dir", |_| {
-        Err(anyhow::anyhow!(
-            "failpoint: tenant-delete-before-remove-tenant-dir"
-        ))?
-    });
-
-    rm(conf.tenant_path(tenant_shard_id), true).await?;
-
-    Ok(())
-}
-
-#[derive(Default)]
-pub enum DeleteTenantFlow {
-    #[default]
-    NotStarted,
-    InProgress,
-    Finished,
-}
-
-impl DeleteTenantFlow {
-    pub(crate) async fn should_resume_deletion(
-        conf: &'static PageServerConf,
-        remote_mark_exists: bool,
-        tenant: &Tenant,
-    ) -> Result<Option<DeletionGuard>, DeleteTenantError> {
-        let acquire = |t: &Tenant| {
-            Some(
-                Arc::clone(&t.delete_progress)
-                    .try_lock_owned()
-                    .expect("we're the only owner during init"),
-            )
-        };
-
-        if remote_mark_exists {
-            return Ok(acquire(tenant));
-        }
-
-        // Check local mark first, if its there there is no need to go to s3 to check whether remote one exists.
-        if conf
-            .tenant_deleted_mark_file_path(&tenant.tenant_shard_id)
-            .exists()
-        {
-            Ok(acquire(tenant))
-        } else {
-            Ok(None)
-        }
-    }
-
-    pub(crate) async fn resume_from_attach(
-        guard: DeletionGuard,
-        tenant: &Arc<Tenant>,
-        preload: Option<TenantPreload>,
-        tenants: &'static std::sync::RwLock<TenantsMap>,
-        ctx: &RequestContext,
-    ) -> Result<(), DeleteTenantError> {
-        let (_, progress) = completion::channel();
-
-        tenant
-            .set_stopping(progress, false, true)
-            .await
-            .expect("cant be stopping or broken");
-
-        tenant
-            .attach(preload, super::SpawnMode::Eager, ctx)
-            .await
-            .context("attach")?;
-
-        Self::background(
-            guard,
-            tenant.conf,
-            tenant.remote_storage.clone(),
-            tenants,
-            tenant,
-        )
-        .await
-    }
-
-    async fn background(
-        mut guard: OwnedMutexGuard<Self>,
-        conf: &PageServerConf,
-        remote_storage: GenericRemoteStorage,
-        tenants: &'static std::sync::RwLock<TenantsMap>,
-        tenant: &Arc<Tenant>,
-    ) -> Result<(), DeleteTenantError> {
-        // Tree sort timelines, schedule delete for them. Mention retries from the console side.
-        // Note that if deletion fails we dont mark timelines as broken,
-        // the whole tenant will become broken as by `Self::schedule_background` logic
-        let already_running_timeline_deletions = schedule_ordered_timeline_deletions(tenant)
-            .await
-            .context("schedule_ordered_timeline_deletions")?;
-
-        fail::fail_point!("tenant-delete-before-polling-ongoing-deletions", |_| {
-            Err(anyhow::anyhow!(
-                "failpoint: tenant-delete-before-polling-ongoing-deletions"
-            ))?
-        });
-
-        // Wait for deletions that were already running at the moment when tenant deletion was requested.
-        // When we can lock deletion guard it means that corresponding timeline deletion finished.
-        for (guard, timeline_id) in already_running_timeline_deletions {
-            let flow = guard.lock().await;
-            if !flow.is_finished() {
-                return Err(DeleteTenantError::Other(anyhow::anyhow!(
-                    "already running timeline deletion failed: {timeline_id}"
-                )));
-            }
-        }
-
-        // Remove top-level tenant objects that don't belong to a timeline, such as heatmap
-        let heatmap_path = remote_heatmap_path(&tenant.tenant_shard_id());
-        if let Some(Err(e)) = backoff::retry(
-            || async {
-                remote_storage
-                    .delete(&heatmap_path, &task_mgr::shutdown_token())
-                    .await
-            },
-            TimeoutOrCancel::caused_by_cancel,
-            FAILED_UPLOAD_WARN_THRESHOLD,
-            FAILED_REMOTE_OP_RETRIES,
-            "remove_remote_tenant_heatmap",
-            &task_mgr::shutdown_token(),
-        )
-        .await
-        {
-            tracing::warn!("Failed to delete heatmap at {heatmap_path}: {e}");
-        }
-
-        let timelines_path = conf.timelines_path(&tenant.tenant_shard_id);
-        // May not exist if we fail in cleanup_remaining_fs_traces after removing it
-        if timelines_path.exists() {
-            // sanity check to guard against layout changes
-            ensure_timelines_dir_empty(&timelines_path)
-                .await
-                .context("timelines dir not empty")?;
-        }
-
-        remove_tenant_remote_delete_mark(
-            conf,
-            &remote_storage,
-            &tenant.tenant_shard_id,
-            &task_mgr::shutdown_token(),
-        )
-        .await?;
-
-        pausable_failpoint!("tenant-delete-before-cleanup-remaining-fs-traces-pausable");
-        fail::fail_point!("tenant-delete-before-cleanup-remaining-fs-traces", |_| {
-            Err(anyhow::anyhow!(
-                "failpoint: tenant-delete-before-cleanup-remaining-fs-traces"
-            ))?
-        });
-
-        cleanup_remaining_fs_traces(conf, &tenant.tenant_shard_id)
-            .await
-            .context("cleanup_remaining_fs_traces")?;
-
-        {
-            // This block is simply removing the TenantSlot for this tenant.  It requires a loop because
-            // we might conflict with a TenantSlot::InProgress marker and need to wait for it.
-            //
-            // This complexity will go away when we simplify how deletion works:
-            // https://github.com/neondatabase/neon/issues/5080
-            loop {
-                // Under the TenantMap lock, try to remove the tenant.  We usually succeed, but if
-                // we encounter an InProgress marker, yield the barrier it contains and wait on it.
-                let barrier = {
-                    let mut locked = tenants.write().unwrap();
-                    let removed = locked.remove(tenant.tenant_shard_id);
-
-                    // FIXME: we should not be modifying this from outside of mgr.rs.
-                    // This will go away when we simplify deletion (https://github.com/neondatabase/neon/issues/5080)
-
-                    // Update stats
-                    match &removed {
-                        TenantsMapRemoveResult::Occupied(slot) => {
-                            crate::metrics::TENANT_MANAGER.slot_removed(slot);
-                        }
-                        TenantsMapRemoveResult::InProgress(barrier) => {
-                            crate::metrics::TENANT_MANAGER
-                                .slot_removed(&TenantSlot::InProgress(barrier.clone()));
-                        }
-                        TenantsMapRemoveResult::Vacant => {
-                            // Nothing changed in map, no metric update
-                        }
-                    }
-
-                    match removed {
-                        TenantsMapRemoveResult::Occupied(TenantSlot::Attached(tenant)) => {
-                            match tenant.current_state() {
-                                TenantState::Stopping { .. } | TenantState::Broken { .. } => {
-                                    // Expected: we put the tenant into stopping state before we start deleting it
-                                }
-                                state => {
-                                    // Unexpected state
-                                    tracing::warn!(
-                                        "Tenant in unexpected state {state} after deletion"
-                                    );
-                                }
-                            }
-                            break;
-                        }
-                        TenantsMapRemoveResult::Occupied(TenantSlot::Secondary(_)) => {
-                            // This is unexpected: this secondary tenants should not have been created, and we
-                            // are not in a position to shut it down from here.
-                            tracing::warn!("Tenant transitioned to secondary mode while deleting!");
-                            break;
-                        }
-                        TenantsMapRemoveResult::Occupied(TenantSlot::InProgress(_)) => {
-                            unreachable!("TenantsMap::remove handles InProgress separately, should never return it here");
-                        }
-                        TenantsMapRemoveResult::Vacant => {
-                            tracing::warn!(
-                                "Tenant removed from TenantsMap before deletion completed"
-                            );
-                            break;
-                        }
-                        TenantsMapRemoveResult::InProgress(barrier) => {
-                            // An InProgress entry was found, we must wait on its barrier
-                            barrier
-                        }
-                    }
-                };
-
-                tracing::info!(
-                    "Waiting for competing operation to complete before deleting state for tenant"
-                );
-                barrier.wait().await;
-            }
-        }
-
-        *guard = Self::Finished;
-
-        Ok(())
-    }
-}

pageserver/src/tenant/disk_btree.rs

@@ -212,6 +212,7 @@ impl<'a, const L: usize> OnDiskNode<'a, L> {
 ///
 /// Public reader object, to search the tree.
 ///
+#[derive(Clone)]
 pub struct DiskBtreeReader<R, const L: usize>
 where
     R: BlockReader,
@@ -259,27 +260,38 @@ where
         Ok(result)
     }
 
-    pub fn iter<'a>(
-        &'a self,
-        start_key: &'a [u8; L],
-        ctx: &'a RequestContext,
-    ) -> DiskBtreeIterator<'a> {
+    pub fn iter<'a>(self, start_key: &'a [u8; L], ctx: &'a RequestContext) -> DiskBtreeIterator<'a>
+    where
+        R: 'a,
+    {
         DiskBtreeIterator {
-            stream: Box::pin(self.get_stream_from(start_key, ctx)),
+            stream: Box::pin(self.into_stream(start_key, ctx)),
         }
     }
 
     /// Return a stream which yields all key, value pairs from the index
     /// starting from the first key greater or equal to `start_key`.
     ///
-    /// Note that this is a copy of [`Self::visit`].
+    /// Note 1: that this is a copy of [`Self::visit`].
     /// TODO: Once the sequential read path is removed this will become
     /// the only index traversal method.
-    pub fn get_stream_from<'a>(
-        &'a self,
+    ///
+    /// Note 2: this function used to take `&self` but it now consumes `self`. This is due to
+    /// the lifetime constraints of the reader and the stream / iterator it creates. Using `&self`
+    /// requires the reader to be present when the stream is used, and this creates a lifetime
+    /// dependency between the reader and the stream. Now if we want to create an iterator that
+    /// holds the stream, someone will need to keep a reference to the reader, which is inconvenient
+    /// to use from the image/delta layer APIs.
+    ///
+    /// Feel free to add the `&self` variant back if it's necessary.
+    pub fn into_stream<'a>(
+        self,
         start_key: &'a [u8; L],
         ctx: &'a RequestContext,
-    ) -> impl Stream<Item = std::result::Result<(Vec<u8>, u64), DiskBtreeError>> + 'a {
+    ) -> impl Stream<Item = std::result::Result<(Vec<u8>, u64), DiskBtreeError>> + 'a
+    where
+        R: 'a,
+    {
         try_stream! {
             let mut stack = Vec::new();
             stack.push((self.root_blk, None));

pageserver/src/tenant/ephemeral_file/page_caching.rs

@@ -158,7 +158,7 @@ impl crate::virtual_file::owned_buffers_io::write::OwnedAsyncWriter for PreWarmi
         let iobuf = match self.file.write_all(buf, ctx).await {
             (iobuf, Ok(nwritten)) => {
                 assert_eq!(nwritten, buflen);
-                iobuf
+                iobuf.into_inner()
             }
             (_, Err(e)) => {
                 return Err(std::io::Error::new(

pageserver/src/tenant/mgr.rs

@@ -51,7 +51,6 @@ use utils::fs_ext::PathExt;
 use utils::generation::Generation;
 use utils::id::{TenantId, TimelineId};
 
-use super::delete::DeleteTenantError;
 use super::remote_timeline_client::remote_tenant_path;
 use super::secondary::SecondaryTenant;
 use super::timeline::detach_ancestor::PreparedTimelineDetach;
@@ -109,12 +108,6 @@ pub(crate) enum TenantsMap {
     ShuttingDown(BTreeMap<TenantShardId, TenantSlot>),
 }
 
-pub(crate) enum TenantsMapRemoveResult {
-    Occupied(TenantSlot),
-    Vacant,
-    InProgress(utils::completion::Barrier),
-}
-
 /// When resolving a TenantId to a shard, we may be looking for the 0th
 /// shard, or we might be looking for whichever shard holds a particular page.
 #[derive(Copy, Clone)]
@@ -191,26 +184,6 @@ impl TenantsMap {
         }
     }
 
-    /// Only for use from DeleteTenantFlow.  This method directly removes a TenantSlot from the map.
-    ///
-    /// The normal way to remove a tenant is using a SlotGuard, which will gracefully remove the guarded
-    /// slot if the enclosed tenant is shutdown.
-    pub(crate) fn remove(&mut self, tenant_shard_id: TenantShardId) -> TenantsMapRemoveResult {
-        use std::collections::btree_map::Entry;
-        match self {
-            TenantsMap::Initializing => TenantsMapRemoveResult::Vacant,
-            TenantsMap::Open(m) | TenantsMap::ShuttingDown(m) => match m.entry(tenant_shard_id) {
-                Entry::Occupied(entry) => match entry.get() {
-                    TenantSlot::InProgress(barrier) => {
-                        TenantsMapRemoveResult::InProgress(barrier.clone())
-                    }
-                    _ => TenantsMapRemoveResult::Occupied(entry.remove()),
-                },
-                Entry::Vacant(_entry) => TenantsMapRemoveResult::Vacant,
-            },
-        }
-    }
-
     #[cfg(all(debug_assertions, not(test)))]
     pub(crate) fn len(&self) -> usize {
         match self {
@@ -460,6 +433,18 @@ async fn init_load_tenant_configs(
     Ok(configs)
 }
 
+#[derive(Debug, thiserror::Error)]
+pub(crate) enum DeleteTenantError {
+    #[error("Tenant map slot error {0}")]
+    SlotError(#[from] TenantSlotError),
+
+    #[error("Cancelled")]
+    Cancelled,
+
+    #[error(transparent)]
+    Other(#[from] anyhow::Error),
+}
+
 /// Initialize repositories with locally available timelines.
 /// Timelines that are only partially available locally (remote storage has more data than this pageserver)
 /// are scheduled for download and added to the tenant once download is completed.
@@ -510,17 +495,8 @@ pub async fn init_tenant_mgr(
         let mut location_conf = match location_conf {
             Ok(l) => l,
             Err(e) => {
-                warn!(tenant_id=%tenant_shard_id.tenant_id, shard_id=%tenant_shard_id.shard_slug(), "Marking tenant broken, failed to {e:#}");
-
-                tenants.insert(
-                    tenant_shard_id,
-                    TenantSlot::Attached(Tenant::create_broken_tenant(
-                        conf,
-                        tenant_shard_id,
-                        resources.remote_storage.clone(),
-                        format!("{}", e),
-                    )),
-                );
+                // This should only happen in the case of a serialization bug or critical local I/O error: we cannot load this tenant
+                error!(tenant_id=%tenant_shard_id.tenant_id, shard_id=%tenant_shard_id.shard_slug(), "Failed to load tenant config, failed to {e:#}");
                 continue;
             }
         };
@@ -629,7 +605,6 @@ pub async fn init_tenant_mgr(
                     AttachedTenantConf::new(location_conf.tenant_conf, attached_conf),
                     shard_identity,
                     Some(init_order.clone()),
-                    &TENANTS,
                     SpawnMode::Lazy,
                     &ctx,
                 ) {
@@ -685,7 +660,6 @@ fn tenant_spawn(
     location_conf: AttachedTenantConf,
     shard_identity: ShardIdentity,
     init_order: Option<InitializationOrder>,
-    tenants: &'static std::sync::RwLock<TenantsMap>,
     mode: SpawnMode,
     ctx: &RequestContext,
 ) -> anyhow::Result<Arc<Tenant>> {
@@ -704,24 +678,16 @@ fn tenant_spawn(
         "Cannot load tenant from empty directory {tenant_path:?}"
     );
 
-    let remote_storage = resources.remote_storage.clone();
-    let tenant = match Tenant::spawn(
+    let tenant = Tenant::spawn(
         conf,
         tenant_shard_id,
         resources,
         location_conf,
         shard_identity,
         init_order,
-        tenants,
         mode,
         ctx,
-    ) {
-        Ok(tenant) => tenant,
-        Err(e) => {
-            error!("Failed to spawn tenant {tenant_shard_id}, reason: {e:#}");
-            Tenant::create_broken_tenant(conf, tenant_shard_id, remote_storage, format!("{e:#}"))
-        }
-    };
+    );
 
     Ok(tenant)
 }
@@ -1161,7 +1127,6 @@ impl TenantManager {
                     attached_conf,
                     shard_identity,
                     None,
-                    self.tenants,
                     spawn_mode,
                     ctx,
                 )?;
@@ -1283,7 +1248,6 @@ impl TenantManager {
             AttachedTenantConf::try_from(config)?,
             shard_identity,
             None,
-            self.tenants,
             SpawnMode::Eager,
             ctx,
         )?;
@@ -1634,7 +1598,7 @@ impl TenantManager {
         for child_shard_id in &child_shards {
             let child_shard_id = *child_shard_id;
             let child_shard = {
-                let locked = TENANTS.read().unwrap();
+                let locked = self.tenants.read().unwrap();
                 let peek_slot =
                     tenant_map_peek_slot(&locked, &child_shard_id, TenantSlotPeekMode::Read)?;
                 peek_slot.and_then(|s| s.get_attached()).cloned()
@@ -1735,6 +1699,7 @@ impl TenantManager {
             let timelines = parent_shard.timelines.lock().unwrap().clone();
             let parent_timelines = timelines.keys().cloned().collect::<Vec<_>>();
             for timeline in timelines.values() {
+                tracing::info!(timeline_id=%timeline.timeline_id, "Loading list of layers to hardlink");
                 let timeline_layers = timeline
                     .layers
                     .read()
@@ -1774,7 +1739,12 @@ impl TenantManager {
 
         // Since we will do a large number of small filesystem metadata operations, batch them into
         // spawn_blocking calls rather than doing each one as a tokio::fs round-trip.
+        let span = tracing::Span::current();
         let jh = tokio::task::spawn_blocking(move || -> anyhow::Result<usize> {
+            // Run this synchronous code in the same log context as the outer function that spawned it.
+            let _span = span.enter();
+
+            tracing::info!("Creating {} directories", create_dirs.len());
             for dir in &create_dirs {
                 if let Err(e) = std::fs::create_dir_all(dir) {
                     // Ignore AlreadyExists errors, drop out on all other errors
@@ -1788,6 +1758,11 @@ impl TenantManager {
             }
 
             for child_prefix in child_prefixes {
+                tracing::info!(
+                    "Hard-linking {} parent layers into child path {}",
+                    parent_layers.len(),
+                    child_prefix
+                );
                 for relative_layer in &parent_layers {
                     let parent_path = parent_path.join(relative_layer);
                     let child_path = child_prefix.join(relative_layer);
@@ -1813,6 +1788,7 @@ impl TenantManager {
             // Durability is not required for correctness, but if we crashed during split and
             // then came restarted with empty timeline dirs, it would be very inefficient to
             // re-populate from remote storage.
+            tracing::info!("fsyncing {} directories", create_dirs.len());
             for dir in create_dirs {
                 if let Err(e) = crashsafe::fsync(&dir) {
                     // Something removed a newly created timeline dir out from underneath us?  Extremely
@@ -1866,7 +1842,7 @@ impl TenantManager {
         deletion_queue_client: &DeletionQueueClient,
     ) -> Result<(), TenantStateError> {
         let tmp_path = self
-            .detach_tenant0(conf, &TENANTS, tenant_shard_id, deletion_queue_client)
+            .detach_tenant0(conf, tenant_shard_id, deletion_queue_client)
             .await?;
         spawn_background_purge(tmp_path);
 
@@ -1876,7 +1852,6 @@ impl TenantManager {
     async fn detach_tenant0(
         &self,
         conf: &'static PageServerConf,
-        tenants: &std::sync::RwLock<TenantsMap>,
         tenant_shard_id: TenantShardId,
         deletion_queue_client: &DeletionQueueClient,
     ) -> Result<Utf8PathBuf, TenantStateError> {
@@ -1890,7 +1865,7 @@ impl TenantManager {
         };
 
         let removal_result = remove_tenant_from_memory(
-            tenants,
+            self.tenants,
             tenant_shard_id,
             tenant_dir_rename_operation(tenant_shard_id),
         )
@@ -1906,7 +1881,7 @@ impl TenantManager {
     pub(crate) fn list_tenants(
         &self,
     ) -> Result<Vec<(TenantShardId, TenantState, Generation)>, TenantMapListError> {
-        let tenants = TENANTS.read().unwrap();
+        let tenants = self.tenants.read().unwrap();
         let m = match &*tenants {
             TenantsMap::Initializing => return Err(TenantMapListError::Initializing),
             TenantsMap::Open(m) | TenantsMap::ShuttingDown(m) => m,
@@ -2007,7 +1982,6 @@ impl TenantManager {
             AttachedTenantConf::try_from(config)?,
             shard_identity,
             None,
-            self.tenants,
             SpawnMode::Eager,
             ctx,
         )?;

pageserver/src/tenant/secondary/downloader.rs

@@ -262,6 +262,7 @@ impl scheduler::RunningJob for RunningDownload {
 struct CompleteDownload {
     secondary_state: Arc<SecondaryTenant>,
     completed_at: Instant,
+    result: Result<(), UpdateError>,
 }
 
 impl scheduler::Completion for CompleteDownload {
@@ -286,21 +287,33 @@ impl JobGenerator<PendingDownload, RunningDownload, CompleteDownload, DownloadCo
         let CompleteDownload {
             secondary_state,
             completed_at: _completed_at,
+            result,
         } = completion;
 
         tracing::debug!("Secondary tenant download completed");
 
         let mut detail = secondary_state.detail.lock().unwrap();
 
-        let period = detail
-            .last_download
-            .as_ref()
-            .map(|d| d.upload_period)
-            .unwrap_or(DEFAULT_DOWNLOAD_INTERVAL);
+        match result {
+            Err(UpdateError::Restart) => {
+                // Start downloading again as soon as we can.  This will involve waiting for the scheduler's
+                // scheduling interval.  This slightly reduces the peak download speed of tenants that hit their
+                // deadline and keep restarting, but that also helps give other tenants a chance to execute rather
+                // that letting one big tenant dominate for a long time.
+                detail.next_download = Some(Instant::now());
+            }
+            _ => {
+                let period = detail
+                    .last_download
+                    .as_ref()
+                    .map(|d| d.upload_period)
+                    .unwrap_or(DEFAULT_DOWNLOAD_INTERVAL);
 
-        // We advance next_download irrespective of errors: we don't want error cases to result in
-        // expensive busy-polling.
-        detail.next_download = Some(Instant::now() + period_jitter(period, 5));
+                // We advance next_download irrespective of errors: we don't want error cases to result in
+                // expensive busy-polling.
+                detail.next_download = Some(Instant::now() + period_jitter(period, 5));
+            }
+        }
     }
 
     async fn schedule(&mut self) -> SchedulingResult<PendingDownload> {
@@ -396,9 +409,10 @@ impl JobGenerator<PendingDownload, RunningDownload, CompleteDownload, DownloadCo
         (RunningDownload { barrier }, Box::pin(async move {
             let _completion = completion;
 
-            match TenantDownloader::new(conf, &remote_storage, &secondary_state)
+            let result = TenantDownloader::new(conf, &remote_storage, &secondary_state)
                 .download(&download_ctx)
-                .await
+                .await;
+            match &result
             {
                 Err(UpdateError::NoData) => {
                     tracing::info!("No heatmap found for tenant.  This is fine if it is new.");
@@ -415,6 +429,9 @@ impl JobGenerator<PendingDownload, RunningDownload, CompleteDownload, DownloadCo
                 Err(e @ (UpdateError::DownloadError(_) | UpdateError::Other(_))) => {
                     tracing::error!("Error while downloading tenant: {e}");
                 },
+                Err(UpdateError::Restart) => {
+                    tracing::info!("Download reached deadline & will restart to update heatmap")
+                }
                 Ok(()) => {}
             };
 
@@ -436,6 +453,7 @@ impl JobGenerator<PendingDownload, RunningDownload, CompleteDownload, DownloadCo
             CompleteDownload {
                 secondary_state,
                 completed_at: Instant::now(),
+                result
             }
         }.instrument(info_span!(parent: None, "secondary_download", tenant_id=%tenant_shard_id.tenant_id, shard_id=%tenant_shard_id.shard_slug()))))
     }
@@ -452,6 +470,11 @@ struct TenantDownloader<'a> {
 /// Errors that may be encountered while updating a tenant
 #[derive(thiserror::Error, Debug)]
 enum UpdateError {
+    /// This is not a true failure, but it's how a download indicates that it would like to be restarted by
+    /// the scheduler, to pick up the latest heatmap
+    #[error("Reached deadline, restarting downloads")]
+    Restart,
+
     #[error("No remote data found")]
     NoData,
     #[error("Insufficient local storage space")]
@@ -603,6 +626,26 @@ impl<'a> TenantDownloader<'a> {
                 self.prepare_timelines(&heatmap, heatmap_mtime).await?;
         }
 
+        // Calculate a deadline for downloads: if downloading takes longer than this, it is useful to drop out and start again,
+        // so that we are always using reasonably a fresh heatmap.  Otherwise, if we had really huge content to download, we might
+        // spend 10s of minutes downloading layers we don't need.
+        // (see https://github.com/neondatabase/neon/issues/8182)
+        let deadline = {
+            let period = self
+                .secondary_state
+                .detail
+                .lock()
+                .unwrap()
+                .last_download
+                .as_ref()
+                .map(|d| d.upload_period)
+                .unwrap_or(DEFAULT_DOWNLOAD_INTERVAL);
+
+            // Use double the period: we are not promising to complete within the period, this is just a heuristic
+            // to keep using a "reasonably fresh" heatmap.
+            Instant::now() + period * 2
+        };
+
         // Download the layers in the heatmap
         for timeline in heatmap.timelines {
             let timeline_state = timeline_states
@@ -618,7 +661,7 @@ impl<'a> TenantDownloader<'a> {
             }
 
             let timeline_id = timeline.timeline_id;
-            self.download_timeline(timeline, timeline_state, ctx)
+            self.download_timeline(timeline, timeline_state, deadline, ctx)
                 .instrument(tracing::info_span!(
                     "secondary_download_timeline",
                     tenant_id=%tenant_shard_id.tenant_id,
@@ -827,26 +870,28 @@ impl<'a> TenantDownloader<'a> {
         .and_then(|x| x)
     }
 
-    async fn download_timeline(
+    /// Download heatmap layers that are not present on local disk, or update their
+    /// access time if they are already present.
+    async fn download_timeline_layers(
         &self,
+        tenant_shard_id: &TenantShardId,
         timeline: HeatMapTimeline,
         timeline_state: SecondaryDetailTimeline,
+        deadline: Instant,
         ctx: &RequestContext,
-    ) -> Result<(), UpdateError> {
-        debug_assert_current_span_has_tenant_and_timeline_id();
-        let tenant_shard_id = self.secondary_state.get_tenant_shard_id();
-
+    ) -> (Result<(), UpdateError>, Vec<HeatMapLayer>) {
         // Accumulate updates to the state
         let mut touched = Vec::new();
 
-        tracing::debug!(timeline_id=%timeline.timeline_id, "Downloading layers, {} in heatmap", timeline.layers.len());
-
-        // Download heatmap layers that are not present on local disk, or update their
-        // access time if they are already present.
         for layer in timeline.layers {
             if self.secondary_state.cancel.is_cancelled() {
                 tracing::debug!("Cancelled -- dropping out of layer loop");
-                return Err(UpdateError::Cancelled);
+                return (Err(UpdateError::Cancelled), touched);
+            }
+
+            if Instant::now() > deadline {
+                // We've been running downloads for a while, restart to download latest heatmap.
+                return (Err(UpdateError::Restart), touched);
             }
 
             // Existing on-disk layers: just update their access time.
@@ -916,20 +961,43 @@ impl<'a> TenantDownloader<'a> {
 
             match self
                 .download_layer(tenant_shard_id, &timeline.timeline_id, layer, ctx)
-                .await?
+                .await
             {
-                Some(layer) => touched.push(layer),
-                None => {
+                Ok(Some(layer)) => touched.push(layer),
+                Ok(None) => {
                     // Not an error but we didn't download it: remote layer is missing.  Don't add it to the list of
                     // things to consider touched.
                 }
+                Err(e) => {
+                    return (Err(e), touched);
+                }
             }
         }
 
-        // Write updates to state to record layers we just downloaded or touched.
+        (Ok(()), touched)
+    }
+
+    async fn download_timeline(
+        &self,
+        timeline: HeatMapTimeline,
+        timeline_state: SecondaryDetailTimeline,
+        deadline: Instant,
+        ctx: &RequestContext,
+    ) -> Result<(), UpdateError> {
+        debug_assert_current_span_has_tenant_and_timeline_id();
+        let tenant_shard_id = self.secondary_state.get_tenant_shard_id();
+        let timeline_id = timeline.timeline_id;
+
+        tracing::debug!(timeline_id=%timeline_id, "Downloading layers, {} in heatmap", timeline.layers.len());
+
+        let (result, touched) = self
+            .download_timeline_layers(tenant_shard_id, timeline, timeline_state, deadline, ctx)
+            .await;
+
+        // Write updates to state to record layers we just downloaded or touched, irrespective of whether the overall result was successful
         {
             let mut detail = self.secondary_state.detail.lock().unwrap();
-            let timeline_detail = detail.timelines.entry(timeline.timeline_id).or_default();
+            let timeline_detail = detail.timelines.entry(timeline_id).or_default();
 
             tracing::info!("Wrote timeline_detail for {} touched layers", touched.len());
 
@@ -943,14 +1011,14 @@ impl<'a> TenantDownloader<'a> {
                         let local_path = local_layer_path(
                             self.conf,
                             tenant_shard_id,
-                            &timeline.timeline_id,
+                            &timeline_id,
                             &t.name,
                             &t.metadata.generation,
                         );
                         e.insert(OnDiskState::new(
                             self.conf,
                             tenant_shard_id,
-                            &timeline.timeline_id,
+                            &timeline_id,
                             t.name,
                             t.metadata.clone(),
                             t.access_time,
@@ -961,7 +1029,7 @@ impl<'a> TenantDownloader<'a> {
             }
         }
 
-        Ok(())
+        result
     }
 
     /// Call this during timeline download if a layer will _not_ be downloaded, to update progress statistics

pageserver/src/tenant/secondary/heatmap_uploader.rs

@@ -367,10 +367,9 @@ async fn upload_tenant_heatmap(
     debug_assert_current_span_has_tenant_id();
 
     let generation = tenant.get_generation();
+    debug_assert!(!generation.is_none());
     if generation.is_none() {
-        // We do not expect this: generations were implemented before heatmap uploads.  However,
-        // handle it so that we don't have to make the generation in the heatmap an Option<>
-        // (Generation::none is not serializable)
+        // We do not expect this: None generations should only appear in historic layer metadata, not in running Tenants
         tracing::warn!("Skipping heatmap upload for tenant with generation==None");
         return Ok(UploadHeatmapOutcome::Skipped);
     }

pageserver/src/tenant/storage_layer/delta_layer.rs

@@ -60,6 +60,7 @@ use std::os::unix::fs::FileExt;
 use std::str::FromStr;
 use std::sync::Arc;
 use tokio::sync::OnceCell;
+use tokio_epoll_uring::{BoundedBuf as _, Slice};
 use tracing::*;
 
 use utils::{
@@ -452,7 +453,8 @@ impl DeltaLayerWriterInner {
         ctx: &RequestContext,
     ) -> (Vec<u8>, anyhow::Result<()>) {
         assert!(self.lsn_range.start <= lsn);
-        let (val, res) = self.blob_writer.write_blob(val, ctx).await;
+        let (val, res) = self.blob_writer.write_blob(val.slice_full(), ctx).await;
+        let val = Slice::into_inner(val);
         let off = match res {
             Ok(off) => off,
             Err(e) => return (val, Err(anyhow::anyhow!(e))),
@@ -505,7 +507,7 @@ impl DeltaLayerWriterInner {
         file.seek(SeekFrom::Start(index_start_blk as u64 * PAGE_SZ as u64))
             .await?;
         for buf in block_buf.blocks {
-            let (_buf, res) = file.write_all(buf, ctx).await;
+            let (_buf, res) = file.write_all(buf.slice_full(), ctx).await;
             res?;
         }
         assert!(self.lsn_range.start < self.lsn_range.end);
@@ -525,7 +527,7 @@ impl DeltaLayerWriterInner {
         // TODO: could use smallvec here but it's a pain with Slice<T>
         Summary::ser_into(&summary, &mut buf)?;
         file.seek(SeekFrom::Start(0)).await?;
-        let (_buf, res) = file.write_all(buf, ctx).await;
+        let (_buf, res) = file.write_all(buf.slice_full(), ctx).await;
         res?;
 
         let metadata = file
@@ -730,7 +732,7 @@ impl DeltaLayer {
         // TODO: could use smallvec here, but it's a pain with Slice<T>
         Summary::ser_into(&new_summary, &mut buf).context("serialize")?;
         file.seek(SeekFrom::Start(0)).await?;
-        let (_buf, res) = file.write_all(buf, ctx).await;
+        let (_buf, res) = file.write_all(buf.slice_full(), ctx).await;
         res?;
         Ok(())
     }
@@ -928,7 +930,6 @@ impl DeltaLayerInner {
     }
 
     /// Load all key-values in the delta layer, should be replaced by an iterator-based interface in the future.
-    #[cfg(test)]
     pub(super) async fn load_key_values(
         &self,
         ctx: &RequestContext,
@@ -941,7 +942,7 @@ impl DeltaLayerInner {
         );
         let mut result = Vec::new();
         let mut stream =
-            Box::pin(self.stream_index_forwards(&index_reader, &[0; DELTA_KEY_SIZE], ctx));
+            Box::pin(self.stream_index_forwards(index_reader, &[0; DELTA_KEY_SIZE], ctx));
         let block_reader = FileBlockReader::new(&self.file, self.file_id);
         let cursor = block_reader.block_cursor();
         let mut buf = Vec::new();
@@ -976,7 +977,7 @@ impl DeltaLayerInner {
         ctx: &RequestContext,
     ) -> anyhow::Result<Vec<VectoredRead>>
     where
-        Reader: BlockReader,
+        Reader: BlockReader + Clone,
     {
         let ctx = RequestContextBuilder::extend(ctx)
             .page_content_kind(PageContentKind::DeltaLayerBtreeNode)
@@ -986,7 +987,7 @@ impl DeltaLayerInner {
             let mut range_end_handled = false;
 
             let start_key = DeltaKey::from_key_lsn(&range.start, lsn_range.start);
-            let index_stream = index_reader.get_stream_from(&start_key.0, &ctx);
+            let index_stream = index_reader.clone().into_stream(&start_key.0, &ctx);
             let mut index_stream = std::pin::pin!(index_stream);
 
             while let Some(index_entry) = index_stream.next().await {
@@ -1241,7 +1242,7 @@ impl DeltaLayerInner {
             block_reader,
         );
 
-        let stream = self.stream_index_forwards(&tree_reader, &[0u8; DELTA_KEY_SIZE], ctx);
+        let stream = self.stream_index_forwards(tree_reader, &[0u8; DELTA_KEY_SIZE], ctx);
         let stream = stream.map_ok(|(key, lsn, pos)| Item::Actual(key, lsn, pos));
         // put in a sentinel value for getting the end offset for last item, and not having to
         // repeat the whole read part
@@ -1300,7 +1301,7 @@ impl DeltaLayerInner {
                         offsets.start.pos(),
                         offsets.end.pos(),
                         meta,
-                        max_read_size,
+                        Some(max_read_size),
                     ))
                 }
             } else {
@@ -1459,17 +1460,17 @@ impl DeltaLayerInner {
 
     fn stream_index_forwards<'a, R>(
         &'a self,
-        reader: &'a DiskBtreeReader<R, DELTA_KEY_SIZE>,
+        reader: DiskBtreeReader<R, DELTA_KEY_SIZE>,
         start: &'a [u8; DELTA_KEY_SIZE],
         ctx: &'a RequestContext,
     ) -> impl futures::stream::Stream<
         Item = Result<(Key, Lsn, BlobRef), crate::tenant::disk_btree::DiskBtreeError>,
     > + 'a
     where
-        R: BlockReader,
+        R: BlockReader + 'a,
     {
         use futures::stream::TryStreamExt;
-        let stream = reader.get_stream_from(start, ctx);
+        let stream = reader.into_stream(start, ctx);
         stream.map_ok(|(key, value)| {
             let key = DeltaKey::from_slice(&key);
             let (key, lsn) = (key.key(), key.lsn());
@@ -1493,6 +1494,24 @@ impl DeltaLayerInner {
         );
         offset
     }
+
+    #[cfg(test)]
+    pub(crate) fn iter<'a>(&'a self, ctx: &'a RequestContext) -> DeltaLayerIterator<'a> {
+        let block_reader = FileBlockReader::new(&self.file, self.file_id);
+        let tree_reader =
+            DiskBtreeReader::new(self.index_start_blk, self.index_root_blk, block_reader);
+        DeltaLayerIterator {
+            delta_layer: self,
+            ctx,
+            index_iter: tree_reader.iter(&[0; DELTA_KEY_SIZE], ctx),
+            key_values_batch: std::collections::VecDeque::new(),
+            is_end: false,
+            planner: crate::tenant::vectored_blob_io::StreamingVectoredReadPlanner::new(
+                1024 * 8192, // The default value. Unit tests might use a different value. 1024 * 8K = 8MB buffer.
+                1024,        // The default value. Unit tests might use a different value
+            ),
+        }
+    }
 }
 
 /// A set of data associated with a delta layer key and its value
@@ -1552,6 +1571,70 @@ impl<'a> pageserver_compaction::interface::CompactionDeltaEntry<'a, Key> for Del
     }
 }
 
+#[cfg(test)]
+pub struct DeltaLayerIterator<'a> {
+    delta_layer: &'a DeltaLayerInner,
+    ctx: &'a RequestContext,
+    planner: crate::tenant::vectored_blob_io::StreamingVectoredReadPlanner,
+    index_iter: crate::tenant::disk_btree::DiskBtreeIterator<'a>,
+    key_values_batch: std::collections::VecDeque<(Key, Lsn, Value)>,
+    is_end: bool,
+}
+
+#[cfg(test)]
+impl<'a> DeltaLayerIterator<'a> {
+    /// Retrieve a batch of key-value pairs into the iterator buffer.
+    async fn next_batch(&mut self) -> anyhow::Result<()> {
+        assert!(self.key_values_batch.is_empty());
+        assert!(!self.is_end);
+
+        let plan = loop {
+            if let Some(res) = self.index_iter.next().await {
+                let (raw_key, value) = res?;
+                let key = Key::from_slice(&raw_key[..KEY_SIZE]);
+                let lsn = DeltaKey::extract_lsn_from_buf(&raw_key);
+                let blob_ref = BlobRef(value);
+                let offset = blob_ref.pos();
+                if let Some(batch_plan) = self.planner.handle(key, lsn, offset, BlobFlag::None) {
+                    break batch_plan;
+                }
+            } else {
+                self.is_end = true;
+                let data_end_offset = self.delta_layer.index_start_offset();
+                break self.planner.handle_range_end(data_end_offset);
+            }
+        };
+        let vectored_blob_reader = VectoredBlobReader::new(&self.delta_layer.file);
+        let mut next_batch = std::collections::VecDeque::new();
+        let buf_size = plan.size();
+        let buf = BytesMut::with_capacity(buf_size);
+        let blobs_buf = vectored_blob_reader
+            .read_blobs(&plan, buf, self.ctx)
+            .await?;
+        let frozen_buf = blobs_buf.buf.freeze();
+        for meta in blobs_buf.blobs.iter() {
+            let value = Value::des(&frozen_buf[meta.start..meta.end])?;
+            next_batch.push_back((meta.meta.key, meta.meta.lsn, value));
+        }
+        self.key_values_batch = next_batch;
+        Ok(())
+    }
+
+    pub async fn next(&mut self) -> anyhow::Result<Option<(Key, Lsn, Value)>> {
+        if self.key_values_batch.is_empty() {
+            if self.is_end {
+                return Ok(None);
+            }
+            self.next_batch().await?;
+        }
+        Ok(Some(
+            self.key_values_batch
+                .pop_front()
+                .expect("should not be empty"),
+        ))
+    }
+}
+
 #[cfg(test)]
 mod test {
     use std::collections::BTreeMap;
@@ -1561,6 +1644,9 @@ mod test {
     use rand::RngCore;
 
     use super::*;
+    use crate::tenant::harness::TIMELINE_ID;
+    use crate::tenant::vectored_blob_io::StreamingVectoredReadPlanner;
+    use crate::tenant::Tenant;
     use crate::{
         context::DownloadBehavior,
         task_mgr::TaskKind,
@@ -1857,7 +1943,7 @@ mod test {
             .finish(entries_meta.key_range.end, &timeline, &ctx)
             .await?;
 
-        let inner = resident.as_delta(&ctx).await?;
+        let inner = resident.get_as_delta(&ctx).await?;
 
         let file_size = inner.file.metadata().await?.len();
         tracing::info!(
@@ -2044,11 +2130,11 @@ mod test {
 
             let copied_layer = writer.finish(Key::MAX, &branch, ctx).await.unwrap();
 
-            copied_layer.as_delta(ctx).await.unwrap();
+            copied_layer.get_as_delta(ctx).await.unwrap();
 
             assert_keys_and_values_eq(
-                new_layer.as_delta(ctx).await.unwrap(),
-                copied_layer.as_delta(ctx).await.unwrap(),
+                new_layer.get_as_delta(ctx).await.unwrap(),
+                copied_layer.get_as_delta(ctx).await.unwrap(),
                 truncate_at,
                 ctx,
             )
@@ -2073,7 +2159,7 @@ mod test {
             source.index_root_blk,
             &source_reader,
         );
-        let source_stream = source.stream_index_forwards(&source_tree, &start_key, ctx);
+        let source_stream = source.stream_index_forwards(source_tree, &start_key, ctx);
         let source_stream = source_stream.filter(|res| match res {
             Ok((_, lsn, _)) => ready(lsn < &truncated_at),
             _ => ready(true),
@@ -2086,7 +2172,7 @@ mod test {
             truncated.index_root_blk,
             &truncated_reader,
         );
-        let truncated_stream = truncated.stream_index_forwards(&truncated_tree, &start_key, ctx);
+        let truncated_stream = truncated.stream_index_forwards(truncated_tree, &start_key, ctx);
         let mut truncated_stream = std::pin::pin!(truncated_stream);
 
         let mut scratch_left = Vec::new();
@@ -2127,4 +2213,116 @@ mod test {
             assert_eq!(utils::Hex(&scratch_left), utils::Hex(&scratch_right));
         }
     }
+
+    async fn produce_delta_layer(
+        tenant: &Tenant,
+        tline: &Arc<Timeline>,
+        mut deltas: Vec<(Key, Lsn, Value)>,
+        ctx: &RequestContext,
+    ) -> anyhow::Result<ResidentLayer> {
+        deltas.sort_by(|(k1, l1, _), (k2, l2, _)| (k1, l1).cmp(&(k2, l2)));
+        let (key_start, _, _) = deltas.first().unwrap();
+        let (key_max, _, _) = deltas.first().unwrap();
+        let lsn_min = deltas.iter().map(|(_, lsn, _)| lsn).min().unwrap();
+        let lsn_max = deltas.iter().map(|(_, lsn, _)| lsn).max().unwrap();
+        let lsn_end = Lsn(lsn_max.0 + 1);
+        let mut writer = DeltaLayerWriter::new(
+            tenant.conf,
+            tline.timeline_id,
+            tenant.tenant_shard_id,
+            *key_start,
+            (*lsn_min)..lsn_end,
+            ctx,
+        )
+        .await?;
+        let key_end = key_max.next();
+
+        for (key, lsn, value) in deltas {
+            writer.put_value(key, lsn, value, ctx).await?;
+        }
+        let delta_layer = writer.finish(key_end, tline, ctx).await?;
+
+        Ok::<_, anyhow::Error>(delta_layer)
+    }
+
+    async fn assert_delta_iter_equal(
+        delta_iter: &mut DeltaLayerIterator<'_>,
+        expect: &[(Key, Lsn, Value)],
+    ) {
+        let mut expect_iter = expect.iter();
+        loop {
+            let o1 = delta_iter.next().await.unwrap();
+            let o2 = expect_iter.next();
+            assert_eq!(o1.is_some(), o2.is_some());
+            if o1.is_none() && o2.is_none() {
+                break;
+            }
+            let (k1, l1, v1) = o1.unwrap();
+            let (k2, l2, v2) = o2.unwrap();
+            assert_eq!(&k1, k2);
+            assert_eq!(l1, *l2);
+            assert_eq!(&v1, v2);
+        }
+    }
+
+    #[tokio::test]
+    async fn delta_layer_iterator() {
+        use crate::repository::Value;
+        use bytes::Bytes;
+
+        let harness = TenantHarness::create("delta_layer_iterator").unwrap();
+        let (tenant, ctx) = harness.load().await;
+
+        let tline = tenant
+            .create_test_timeline(TIMELINE_ID, Lsn(0x10), DEFAULT_PG_VERSION, &ctx)
+            .await
+            .unwrap();
+
+        fn get_key(id: u32) -> Key {
+            let mut key = Key::from_hex("000000000033333333444444445500000000").unwrap();
+            key.field6 = id;
+            key
+        }
+        const N: usize = 1000;
+        let test_deltas = (0..N)
+            .map(|idx| {
+                (
+                    get_key(idx as u32 / 10),
+                    Lsn(0x10 * ((idx as u64) % 10 + 1)),
+                    Value::Image(Bytes::from(format!("img{idx:05}"))),
+                )
+            })
+            .collect_vec();
+        let resident_layer = produce_delta_layer(&tenant, &tline, test_deltas.clone(), &ctx)
+            .await
+            .unwrap();
+        let delta_layer = resident_layer.get_as_delta(&ctx).await.unwrap();
+        for max_read_size in [1, 1024] {
+            for batch_size in [1, 2, 4, 8, 3, 7, 13] {
+                println!("running with batch_size={batch_size} max_read_size={max_read_size}");
+                // Test if the batch size is correctly determined
+                let mut iter = delta_layer.iter(&ctx);
+                iter.planner = StreamingVectoredReadPlanner::new(max_read_size, batch_size);
+                let mut num_items = 0;
+                for _ in 0..3 {
+                    iter.next_batch().await.unwrap();
+                    num_items += iter.key_values_batch.len();
+                    if max_read_size == 1 {
+                        // every key should be a batch b/c the value is larger than max_read_size
+                        assert_eq!(iter.key_values_batch.len(), 1);
+                    } else {
+                        assert_eq!(iter.key_values_batch.len(), batch_size);
+                    }
+                    if num_items >= N {
+                        break;
+                    }
+                    iter.key_values_batch.clear();
+                }
+                // Test if the result is correct
+                let mut iter = delta_layer.iter(&ctx);
+                iter.planner = StreamingVectoredReadPlanner::new(max_read_size, batch_size);
+                assert_delta_iter_equal(&mut iter, &test_deltas).await;
+            }
+        }
+    }
 }

pageserver/src/tenant/storage_layer/image_layer.rs

@@ -341,6 +341,7 @@ impl ImageLayer {
     where
         F: Fn(Summary) -> Summary,
     {
+        use tokio_epoll_uring::BoundedBuf as _;
         let mut file = VirtualFile::open_with_options(
             path,
             virtual_file::OpenOptions::new().read(true).write(true),
@@ -362,7 +363,7 @@ impl ImageLayer {
         // TODO: could use smallvec here but it's a pain with Slice<T>
         Summary::ser_into(&new_summary, &mut buf).context("serialize")?;
         file.seek(SeekFrom::Start(0)).await?;
-        let (_buf, res) = file.write_all(buf, ctx).await;
+        let (_buf, res) = file.write_all(buf.slice_full(), ctx).await;
         res?;
         Ok(())
     }
@@ -486,7 +487,6 @@ impl ImageLayerInner {
     }
 
     /// Load all key-values in the delta layer, should be replaced by an iterator-based interface in the future.
-    #[cfg(test)]
     pub(super) async fn load_key_values(
         &self,
         ctx: &RequestContext,
@@ -495,7 +495,7 @@ impl ImageLayerInner {
         let tree_reader =
             DiskBtreeReader::new(self.index_start_blk, self.index_root_blk, &block_reader);
         let mut result = Vec::new();
-        let mut stream = Box::pin(tree_reader.get_stream_from(&[0; KEY_SIZE], ctx));
+        let mut stream = Box::pin(tree_reader.into_stream(&[0; KEY_SIZE], ctx));
         let block_reader = FileBlockReader::new(&self.file, self.file_id);
         let cursor = block_reader.block_cursor();
         while let Some(item) = stream.next().await {
@@ -544,7 +544,7 @@ impl ImageLayerInner {
             let mut search_key: [u8; KEY_SIZE] = [0u8; KEY_SIZE];
             range.start.write_to_byte_slice(&mut search_key);
 
-            let index_stream = tree_reader.get_stream_from(&search_key, &ctx);
+            let index_stream = tree_reader.clone().into_stream(&search_key, &ctx);
             let mut index_stream = std::pin::pin!(index_stream);
 
             while let Some(index_entry) = index_stream.next().await {
@@ -689,6 +689,24 @@ impl ImageLayerInner {
             };
         }
     }
+
+    #[cfg(test)]
+    pub(crate) fn iter<'a>(&'a self, ctx: &'a RequestContext) -> ImageLayerIterator<'a> {
+        let block_reader = FileBlockReader::new(&self.file, self.file_id);
+        let tree_reader =
+            DiskBtreeReader::new(self.index_start_blk, self.index_root_blk, block_reader);
+        ImageLayerIterator {
+            image_layer: self,
+            ctx,
+            index_iter: tree_reader.iter(&[0; KEY_SIZE], ctx),
+            key_values_batch: std::collections::VecDeque::new(),
+            is_end: false,
+            planner: crate::tenant::vectored_blob_io::StreamingVectoredReadPlanner::new(
+                1024 * 8192, // The default value. Unit tests might use a different value. 1024 * 8K = 8MB buffer.
+                1024,        // The default value. Unit tests might use a different value
+            ),
+        }
+    }
 }
 
 /// A builder object for constructing a new image layer.
@@ -781,8 +799,9 @@ impl ImageLayerWriterInner {
         img: Bytes,
         ctx: &RequestContext,
     ) -> anyhow::Result<()> {
+        use tokio_epoll_uring::BoundedBuf as _;
         ensure!(self.key_range.contains(&key));
-        let (_img, res) = self.blob_writer.write_blob(img, ctx).await;
+        let (_img, res) = self.blob_writer.write_blob(img.slice_full(), ctx).await;
         // TODO: re-use the buffer for `img` further upstack
         let off = res?;
 
@@ -801,6 +820,7 @@ impl ImageLayerWriterInner {
         timeline: &Arc<Timeline>,
         ctx: &RequestContext,
     ) -> anyhow::Result<ResidentLayer> {
+        use tokio_epoll_uring::BoundedBuf as _;
         let index_start_blk =
             ((self.blob_writer.size() + PAGE_SZ as u64 - 1) / PAGE_SZ as u64) as u32;
 
@@ -811,7 +831,7 @@ impl ImageLayerWriterInner {
             .await?;
         let (index_root_blk, block_buf) = self.tree.finish()?;
         for buf in block_buf.blocks {
-            let (_buf, res) = file.write_all(buf, ctx).await;
+            let (_slice, res) = file.write_all(buf.slice_full(), ctx).await;
             res?;
         }
 
@@ -831,7 +851,7 @@ impl ImageLayerWriterInner {
         // TODO: could use smallvec here but it's a pain with Slice<T>
         Summary::ser_into(&summary, &mut buf)?;
         file.seek(SeekFrom::Start(0)).await?;
-        let (_buf, res) = file.write_all(buf, ctx).await;
+        let (_slice, res) = file.write_all(buf.slice_full(), ctx).await;
         res?;
 
         let metadata = file
@@ -943,11 +963,77 @@ impl Drop for ImageLayerWriter {
     }
 }
 
+#[cfg(test)]
+pub struct ImageLayerIterator<'a> {
+    image_layer: &'a ImageLayerInner,
+    ctx: &'a RequestContext,
+    planner: crate::tenant::vectored_blob_io::StreamingVectoredReadPlanner,
+    index_iter: crate::tenant::disk_btree::DiskBtreeIterator<'a>,
+    key_values_batch: std::collections::VecDeque<(Key, Lsn, Value)>,
+    is_end: bool,
+}
+
+#[cfg(test)]
+impl<'a> ImageLayerIterator<'a> {
+    /// Retrieve a batch of key-value pairs into the iterator buffer.
+    async fn next_batch(&mut self) -> anyhow::Result<()> {
+        assert!(self.key_values_batch.is_empty());
+        assert!(!self.is_end);
+
+        let plan = loop {
+            if let Some(res) = self.index_iter.next().await {
+                let (raw_key, offset) = res?;
+                if let Some(batch_plan) = self.planner.handle(
+                    Key::from_slice(&raw_key[..KEY_SIZE]),
+                    self.image_layer.lsn,
+                    offset,
+                    BlobFlag::None,
+                ) {
+                    break batch_plan;
+                }
+            } else {
+                self.is_end = true;
+                let payload_end = self.image_layer.index_start_blk as u64 * PAGE_SZ as u64;
+                break self.planner.handle_range_end(payload_end);
+            }
+        };
+        let vectored_blob_reader = VectoredBlobReader::new(&self.image_layer.file);
+        let mut next_batch = std::collections::VecDeque::new();
+        let buf_size = plan.size();
+        let buf = BytesMut::with_capacity(buf_size);
+        let blobs_buf = vectored_blob_reader
+            .read_blobs(&plan, buf, self.ctx)
+            .await?;
+        let frozen_buf: Bytes = blobs_buf.buf.freeze();
+        for meta in blobs_buf.blobs.iter() {
+            let img_buf = frozen_buf.slice(meta.start..meta.end);
+            next_batch.push_back((meta.meta.key, self.image_layer.lsn, Value::Image(img_buf)));
+        }
+        self.key_values_batch = next_batch;
+        Ok(())
+    }
+
+    pub async fn next(&mut self) -> anyhow::Result<Option<(Key, Lsn, Value)>> {
+        if self.key_values_batch.is_empty() {
+            if self.is_end {
+                return Ok(None);
+            }
+            self.next_batch().await?;
+        }
+        Ok(Some(
+            self.key_values_batch
+                .pop_front()
+                .expect("should not be empty"),
+        ))
+    }
+}
+
 #[cfg(test)]
 mod test {
-    use std::time::Duration;
+    use std::{sync::Arc, time::Duration};
 
     use bytes::Bytes;
+    use itertools::Itertools;
     use pageserver_api::{
         key::Key,
         shard::{ShardCount, ShardIdentity, ShardNumber, ShardStripeSize},
@@ -959,11 +1045,19 @@ mod test {
     };
 
     use crate::{
-        tenant::{config::TenantConf, harness::TenantHarness},
+        context::RequestContext,
+        repository::Value,
+        tenant::{
+            config::TenantConf,
+            harness::{TenantHarness, TIMELINE_ID},
+            storage_layer::ResidentLayer,
+            vectored_blob_io::StreamingVectoredReadPlanner,
+            Tenant, Timeline,
+        },
         DEFAULT_PG_VERSION,
     };
 
-    use super::ImageLayerWriter;
+    use super::{ImageLayerIterator, ImageLayerWriter};
 
     #[tokio::test]
     async fn image_layer_rewrite() {
@@ -1134,4 +1228,111 @@ mod test {
             }
         }
     }
+
+    async fn produce_image_layer(
+        tenant: &Tenant,
+        tline: &Arc<Timeline>,
+        mut images: Vec<(Key, Bytes)>,
+        lsn: Lsn,
+        ctx: &RequestContext,
+    ) -> anyhow::Result<ResidentLayer> {
+        images.sort();
+        let (key_start, _) = images.first().unwrap();
+        let (key_last, _) = images.last().unwrap();
+        let key_end = key_last.next();
+        let key_range = *key_start..key_end;
+        let mut writer = ImageLayerWriter::new(
+            tenant.conf,
+            tline.timeline_id,
+            tenant.tenant_shard_id,
+            &key_range,
+            lsn,
+            ctx,
+        )
+        .await?;
+
+        for (key, img) in images {
+            writer.put_image(key, img, ctx).await?;
+        }
+        let img_layer = writer.finish(tline, ctx).await?;
+
+        Ok::<_, anyhow::Error>(img_layer)
+    }
+
+    async fn assert_img_iter_equal(
+        img_iter: &mut ImageLayerIterator<'_>,
+        expect: &[(Key, Bytes)],
+        expect_lsn: Lsn,
+    ) {
+        let mut expect_iter = expect.iter();
+        loop {
+            let o1 = img_iter.next().await.unwrap();
+            let o2 = expect_iter.next();
+            match (o1, o2) {
+                (None, None) => break,
+                (Some((k1, l1, v1)), Some((k2, i2))) => {
+                    let Value::Image(i1) = v1 else {
+                        panic!("expect Value::Image")
+                    };
+                    assert_eq!(&k1, k2);
+                    assert_eq!(l1, expect_lsn);
+                    assert_eq!(&i1, i2);
+                }
+                (o1, o2) => panic!("iterators length mismatch: {:?}, {:?}", o1, o2),
+            }
+        }
+    }
+
+    #[tokio::test]
+    async fn image_layer_iterator() {
+        let harness = TenantHarness::create("image_layer_iterator").unwrap();
+        let (tenant, ctx) = harness.load().await;
+
+        let tline = tenant
+            .create_test_timeline(TIMELINE_ID, Lsn(0x10), DEFAULT_PG_VERSION, &ctx)
+            .await
+            .unwrap();
+
+        fn get_key(id: u32) -> Key {
+            let mut key = Key::from_hex("000000000033333333444444445500000000").unwrap();
+            key.field6 = id;
+            key
+        }
+        const N: usize = 1000;
+        let test_imgs = (0..N)
+            .map(|idx| (get_key(idx as u32), Bytes::from(format!("img{idx:05}"))))
+            .collect_vec();
+        let resident_layer =
+            produce_image_layer(&tenant, &tline, test_imgs.clone(), Lsn(0x10), &ctx)
+                .await
+                .unwrap();
+        let img_layer = resident_layer.get_as_image(&ctx).await.unwrap();
+        for max_read_size in [1, 1024] {
+            for batch_size in [1, 2, 4, 8, 3, 7, 13] {
+                println!("running with batch_size={batch_size} max_read_size={max_read_size}");
+                // Test if the batch size is correctly determined
+                let mut iter = img_layer.iter(&ctx);
+                iter.planner = StreamingVectoredReadPlanner::new(max_read_size, batch_size);
+                let mut num_items = 0;
+                for _ in 0..3 {
+                    iter.next_batch().await.unwrap();
+                    num_items += iter.key_values_batch.len();
+                    if max_read_size == 1 {
+                        // every key should be a batch b/c the value is larger than max_read_size
+                        assert_eq!(iter.key_values_batch.len(), 1);
+                    } else {
+                        assert_eq!(iter.key_values_batch.len(), batch_size);
+                    }
+                    if num_items >= N {
+                        break;
+                    }
+                    iter.key_values_batch.clear();
+                }
+                // Test if the result is correct
+                let mut iter = img_layer.iter(&ctx);
+                iter.planner = StreamingVectoredReadPlanner::new(max_read_size, batch_size);
+                assert_img_iter_equal(&mut iter, &test_imgs, Lsn(0x10)).await;
+            }
+        }
+    }
 }

pageserver/src/tenant/storage_layer/inmemory_layer.rs

@@ -622,18 +622,16 @@ impl InMemoryLayer {
 
         let end_lsn = *self.end_lsn.get().unwrap();
 
-        let keys: Vec<_> = if let Some(key_range) = key_range {
+        let key_count = if let Some(key_range) = key_range {
             inner
                 .index
                 .iter()
                 .filter(|(k, _)| key_range.contains(k))
-                .map(|(k, m)| (k.to_i128(), m))
-                .collect()
+                .count()
         } else {
-            inner.index.iter().map(|(k, m)| (k.to_i128(), m)).collect()
+            inner.index.len()
         };
-
-        if keys.is_empty() {
+        if key_count == 0 {
             return Ok(None);
         }
 

pageserver/src/tenant/storage_layer/layer.rs

@@ -93,16 +93,12 @@ pub(crate) struct Layer(Arc<LayerInner>);
 
 impl std::fmt::Display for Layer {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        if matches!(self.0.generation, Generation::Broken) {
-            write!(f, "{}-broken", self.layer_desc().short_id())
-        } else {
-            write!(
-                f,
-                "{}{}",
-                self.layer_desc().short_id(),
-                self.0.generation.get_suffix()
-            )
-        }
+        write!(
+            f,
+            "{}{}",
+            self.layer_desc().short_id(),
+            self.0.generation.get_suffix()
+        )
     }
 }
 
@@ -389,7 +385,6 @@ impl Layer {
     }
 
     /// Get all key/values in the layer. Should be replaced with an iterator-based API in the future.
-    #[cfg(test)]
     pub(crate) async fn load_key_values(
         &self,
         ctx: &RequestContext,
@@ -1774,7 +1769,6 @@ impl DownloadedLayer {
         }
     }
 
-    #[cfg(test)]
     async fn load_key_values(
         &self,
         owner: &Arc<LayerInner>,
@@ -1905,7 +1899,7 @@ impl ResidentLayer {
     }
 
     #[cfg(test)]
-    pub(crate) async fn as_delta(
+    pub(crate) async fn get_as_delta(
         &self,
         ctx: &RequestContext,
     ) -> anyhow::Result<&delta_layer::DeltaLayerInner> {
@@ -1915,6 +1909,18 @@ impl ResidentLayer {
             Image(_) => Err(anyhow::anyhow!("image layer")),
         }
     }
+
+    #[cfg(test)]
+    pub(crate) async fn get_as_image(
+        &self,
+        ctx: &RequestContext,
+    ) -> anyhow::Result<&image_layer::ImageLayerInner> {
+        use LayerKind::*;
+        match self.downloaded.get(&self.owner.0, ctx).await? {
+            Image(ref d) => Ok(d),
+            Delta(_) => Err(anyhow::anyhow!("delta layer")),
+        }
+    }
 }
 
 impl AsLayerDesc for ResidentLayer {

pageserver/src/tenant/timeline.rs

@@ -686,6 +686,7 @@ pub enum GetLogicalSizePriority {
 pub(crate) enum CompactFlags {
     ForceRepartition,
     ForceImageLayerCreation,
+    EnhancedGcBottomMostCompaction,
 }
 
 impl std::fmt::Debug for Timeline {
@@ -1096,7 +1097,6 @@ impl Timeline {
     /// scan iterator interface. We could optimize this interface later to avoid some checks in the vectored
     /// get path to maintain and split the probing and to-be-probe keyspace. We also need to ensure that
     /// the scan operation will not cause OOM in the future.
-    #[allow(dead_code)]
     pub(crate) async fn scan(
         &self,
         keyspace: KeySpace,
@@ -5481,12 +5481,12 @@ impl Timeline {
         }
         images.sort_unstable_by(|(ka, _), (kb, _)| ka.cmp(kb));
         let min_key = *images.first().map(|(k, _)| k).unwrap();
-        let max_key = images.last().map(|(k, _)| k).unwrap().next();
+        let end_key = images.last().map(|(k, _)| k).unwrap().next();
         let mut image_layer_writer = ImageLayerWriter::new(
             self.conf,
             self.timeline_id,
             self.tenant_shard_id,
-            &(min_key..max_key),
+            &(min_key..end_key),
             lsn,
             ctx,
         )
@@ -5518,7 +5518,7 @@ impl Timeline {
         let last_record_lsn = self.get_last_record_lsn();
         deltas.sort_unstable_by(|(ka, la, _), (kb, lb, _)| (ka, la).cmp(&(kb, lb)));
         let min_key = *deltas.first().map(|(k, _, _)| k).unwrap();
-        let max_key = deltas.last().map(|(k, _, _)| k).unwrap().next();
+        let end_key = deltas.last().map(|(k, _, _)| k).unwrap().next();
         let min_lsn = *deltas.iter().map(|(_, lsn, _)| lsn).min().unwrap();
         let max_lsn = *deltas.iter().map(|(_, lsn, _)| lsn).max().unwrap();
         assert!(
@@ -5541,7 +5541,7 @@ impl Timeline {
         for (key, lsn, val) in deltas {
             delta_layer_writer.put_value(key, lsn, val, ctx).await?;
         }
-        let delta_layer = delta_layer_writer.finish(max_key, self, ctx).await?;
+        let delta_layer = delta_layer_writer.finish(end_key, self, ctx).await?;
 
         {
             let mut guard = self.layers.write().await;

pageserver/src/tenant/timeline/compaction.rs

@@ -47,10 +47,14 @@ impl Timeline {
     /// TODO: cancellation
     pub(crate) async fn compact_legacy(
         self: &Arc<Self>,
-        _cancel: &CancellationToken,
+        cancel: &CancellationToken,
         flags: EnumSet<CompactFlags>,
         ctx: &RequestContext,
     ) -> Result<(), CompactionError> {
+        if flags.contains(CompactFlags::EnhancedGcBottomMostCompaction) {
+            return self.compact_with_gc(cancel, ctx).await;
+        }
+
         // High level strategy for compaction / image creation:
         //
         // 1. First, calculate the desired "partitioning" of the
@@ -959,13 +963,20 @@ impl Timeline {
     /// the GC horizon without considering retain_lsns. Then, it does a full compaction over all these delta
     /// layers and image layers, which generates image layers on the gc horizon, drop deltas below gc horizon,
     /// and create delta layers with all deltas >= gc horizon.
-    #[cfg(test)]
     pub(crate) async fn compact_with_gc(
         self: &Arc<Self>,
         _cancel: &CancellationToken,
         ctx: &RequestContext,
     ) -> Result<(), CompactionError> {
         use crate::tenant::storage_layer::ValueReconstructState;
+        use std::collections::BTreeSet;
+
+        info!("running enhanced gc bottom-most compaction");
+
+        scopeguard::defer! {
+            info!("done enhanced gc bottom-most compaction");
+        };
+
         // Step 0: pick all delta layers + image layers below/intersect with the GC horizon.
         // The layer selection has the following properties:
         // 1. If a layer is in the selection, all layers below it are in the selection.
@@ -974,6 +985,11 @@ impl Timeline {
             let guard = self.layers.read().await;
             let layers = guard.layer_map();
             let gc_info = self.gc_info.read().unwrap();
+            if !gc_info.retain_lsns.is_empty() || !gc_info.leases.is_empty() {
+                return Err(CompactionError::Other(anyhow!(
+                    "enhanced legacy compaction currently does not support retain_lsns (branches)"
+                )));
+            }
             let gc_cutoff = Lsn::min(gc_info.cutoffs.horizon, gc_info.cutoffs.pitr);
             let mut selected_layers = Vec::new();
             // TODO: consider retain_lsns
@@ -985,21 +1001,36 @@ impl Timeline {
             }
             (selected_layers, gc_cutoff)
         };
+        info!(
+            "picked {} layers for compaction with gc_cutoff={}",
+            layer_selection.len(),
+            gc_cutoff
+        );
         // Step 1: (In the future) construct a k-merge iterator over all layers. For now, simply collect all keys + LSNs.
+        // Also, collect the layer information to decide when to split the new delta layers.
         let mut all_key_values = Vec::new();
+        let mut delta_split_points = BTreeSet::new();
         for layer in &layer_selection {
             all_key_values.extend(layer.load_key_values(ctx).await?);
+            let desc = layer.layer_desc();
+            if desc.is_delta() {
+                // TODO: is it correct to only record split points for deltas intersecting with the GC horizon? (exclude those below/above the horizon)
+                // so that we can avoid having too many small delta layers.
+                let key_range = desc.get_key_range();
+                delta_split_points.insert(key_range.start);
+                delta_split_points.insert(key_range.end);
+            }
         }
         // Key small to large, LSN low to high, if the same LSN has both image and delta due to the merge of delta layers and
-        // image layers, make image appear later than delta.
+        // image layers, make image appear before than delta.
         struct ValueWrapper<'a>(&'a crate::repository::Value);
         impl Ord for ValueWrapper<'_> {
             fn cmp(&self, other: &Self) -> std::cmp::Ordering {
                 use crate::repository::Value;
                 use std::cmp::Ordering;
                 match (self.0, other.0) {
-                    (Value::Image(_), Value::WalRecord(_)) => Ordering::Greater,
-                    (Value::WalRecord(_), Value::Image(_)) => Ordering::Less,
+                    (Value::Image(_), Value::WalRecord(_)) => Ordering::Less,
+                    (Value::WalRecord(_), Value::Image(_)) => Ordering::Greater,
                     _ => Ordering::Equal,
                 }
             }
@@ -1018,13 +1049,6 @@ impl Timeline {
         all_key_values.sort_by(|(k1, l1, v1), (k2, l2, v2)| {
             (k1, l1, ValueWrapper(v1)).cmp(&(k2, l2, ValueWrapper(v2)))
         });
-        let max_lsn = all_key_values
-            .iter()
-            .map(|(_, lsn, _)| lsn)
-            .max()
-            .copied()
-            .unwrap()
-            + 1;
         // Step 2: Produce images+deltas. TODO: ensure newly-produced delta does not overlap with other deltas.
         // Data of the same key.
         let mut accumulated_values = Vec::new();
@@ -1043,14 +1067,24 @@ impl Timeline {
             // We have a list of deltas/images. We want to create image layers while collect garbages.
             for (key, lsn, val) in accumulated_values.iter().rev() {
                 if *lsn > horizon {
-                    keys_above_horizon.push((*key, *lsn, val.clone())); // TODO: ensure one LSN corresponds to either delta or image instead of both
+                    if let Some((_, prev_lsn, _)) = keys_above_horizon.last_mut() {
+                        if *prev_lsn == *lsn {
+                            // The case that we have an LSN with both data from the delta layer and the image layer. As
+                            // `ValueWrapper` ensures that an image is ordered before a delta at the same LSN, we simply
+                            // drop this delta and keep the image.
+                            //
+                            // For example, we have delta layer key1@0x10, key1@0x20, and image layer key1@0x10, we will
+                            // keep the image for key1@0x10 and the delta for key1@0x20. key1@0x10 delta will be simply
+                            // dropped.
+                            continue;
+                        }
+                    }
+                    keys_above_horizon.push((*key, *lsn, val.clone()));
                 } else if *lsn <= horizon {
                     match val {
                         crate::repository::Value::Image(image) => {
-                            if lsn <= &horizon {
-                                base_image = Some((*lsn, image.clone()));
-                                break;
-                            }
+                            base_image = Some((*lsn, image.clone()));
+                            break;
                         }
                         crate::repository::Value::WalRecord(wal) => {
                             delta_above_base_image.push((*lsn, wal.clone()));
@@ -1058,7 +1092,7 @@ impl Timeline {
                     }
                 }
             }
-            delta_above_base_image.reverse();
+            // do not reverse delta_above_base_image, reconstruct state expects reversely-ordered records
             keys_above_horizon.reverse();
             let state = ValueReconstructState {
                 img: base_image,
@@ -1068,15 +1102,59 @@ impl Timeline {
             Ok((keys_above_horizon, img))
         }
 
-        let mut delta_layer_writer = DeltaLayerWriter::new(
-            self.conf,
-            self.timeline_id,
-            self.tenant_shard_id,
-            all_key_values.first().unwrap().0,
-            gc_cutoff..max_lsn, // TODO: off by one?
-            ctx,
-        )
-        .await?;
+        async fn flush_deltas(
+            deltas: &mut Vec<(Key, Lsn, crate::repository::Value)>,
+            last_key: Key,
+            delta_split_points: &[Key],
+            current_delta_split_point: &mut usize,
+            tline: &Arc<Timeline>,
+            gc_cutoff: Lsn,
+            ctx: &RequestContext,
+        ) -> anyhow::Result<Option<ResidentLayer>> {
+            // Check if we need to split the delta layer. We split at the original delta layer boundary to avoid
+            // overlapping layers.
+            //
+            // If we have a structure like this:
+            //
+            // | Delta 1 |         | Delta 4 |
+            // |---------| Delta 2 |---------|
+            // | Delta 3 |         | Delta 5 |
+            //
+            // And we choose to compact delta 2+3+5. We will get an overlapping delta layer with delta 1+4.
+            // A simple solution here is to split the delta layers using the original boundary, while this
+            // might produce a lot of small layers. This should be improved and fixed in the future.
+            let mut need_split = false;
+            while *current_delta_split_point < delta_split_points.len()
+                && last_key >= delta_split_points[*current_delta_split_point]
+            {
+                *current_delta_split_point += 1;
+                need_split = true;
+            }
+            if !need_split {
+                return Ok(None);
+            }
+            let deltas = std::mem::take(deltas);
+            if deltas.is_empty() {
+                return Ok(None);
+            }
+            let end_lsn = deltas.iter().map(|(_, lsn, _)| lsn).max().copied().unwrap() + 1;
+            let mut delta_layer_writer = DeltaLayerWriter::new(
+                tline.conf,
+                tline.timeline_id,
+                tline.tenant_shard_id,
+                deltas.first().unwrap().0,
+                gc_cutoff..end_lsn,
+                ctx,
+            )
+            .await?;
+            let key_end = deltas.last().unwrap().0.next();
+            for (key, lsn, val) in deltas {
+                delta_layer_writer.put_value(key, lsn, val, ctx).await?;
+            }
+            let delta_layer = delta_layer_writer.finish(key_end, tline, ctx).await?;
+            Ok(Some(delta_layer))
+        }
+
         let mut image_layer_writer = ImageLayerWriter::new(
             self.conf,
             self.timeline_id,
@@ -1087,6 +1165,10 @@ impl Timeline {
         )
         .await?;
 
+        let mut delta_values = Vec::new();
+        let delta_split_points = delta_split_points.into_iter().collect_vec();
+        let mut current_delta_split_point = 0;
+        let mut delta_layers = Vec::new();
         for item @ (key, _, _) in &all_key_values {
             if &last_key == key {
                 accumulated_values.push(item);
@@ -1094,34 +1176,63 @@ impl Timeline {
                 let (deltas, image) =
                     flush_accumulated_states(self, last_key, &accumulated_values, gc_cutoff)
                         .await?;
+                // Put the image into the image layer. Currently we have a single big layer for the compaction.
                 image_layer_writer.put_image(last_key, image, ctx).await?;
-                for (key, lsn, val) in deltas {
-                    delta_layer_writer.put_value(key, lsn, val, ctx).await?;
-                }
+                delta_values.extend(deltas);
+                delta_layers.extend(
+                    flush_deltas(
+                        &mut delta_values,
+                        last_key,
+                        &delta_split_points,
+                        &mut current_delta_split_point,
+                        self,
+                        gc_cutoff,
+                        ctx,
+                    )
+                    .await?,
+                );
                 accumulated_values.clear();
                 accumulated_values.push(item);
                 last_key = *key;
             }
         }
+
+        // TODO: move this part to the loop body
         let (deltas, image) =
             flush_accumulated_states(self, last_key, &accumulated_values, gc_cutoff).await?;
+        // Put the image into the image layer. Currently we have a single big layer for the compaction.
         image_layer_writer.put_image(last_key, image, ctx).await?;
-        for (key, lsn, val) in deltas {
-            delta_layer_writer.put_value(key, lsn, val, ctx).await?;
-        }
-        accumulated_values.clear();
-        // TODO: split layers
-        let delta_layer = delta_layer_writer.finish(last_key, self, ctx).await?;
+        delta_values.extend(deltas);
+        delta_layers.extend(
+            flush_deltas(
+                &mut delta_values,
+                last_key,
+                &delta_split_points,
+                &mut current_delta_split_point,
+                self,
+                gc_cutoff,
+                ctx,
+            )
+            .await?,
+        );
+
         let image_layer = image_layer_writer.finish(self, ctx).await?;
+        info!(
+            "produced {} delta layers and {} image layers",
+            delta_layers.len(),
+            1
+        );
+        let mut compact_to = Vec::new();
+        compact_to.extend(delta_layers);
+        compact_to.push(image_layer);
         // Step 3: Place back to the layer map.
         {
             let mut guard = self.layers.write().await;
-            guard.finish_gc_compaction(
-                &layer_selection,
-                &[delta_layer.clone(), image_layer.clone()],
-                &self.metrics,
-            )
+            guard.finish_gc_compaction(&layer_selection, &compact_to, &self.metrics)
         };
+
+        self.remote_client
+            .schedule_compaction_update(&layer_selection, &compact_to)?;
         Ok(())
     }
 }

pageserver/src/tenant/timeline/delete.rs

@@ -255,7 +255,6 @@ impl DeleteTimelineFlow {
     }
 
     /// Shortcut to create Timeline in stopping state and spawn deletion task.
-    /// See corresponding parts of [`crate::tenant::delete::DeleteTenantFlow`]
     #[instrument(skip_all, fields(%timeline_id))]
     pub async fn resume_deletion(
         tenant: Arc<Tenant>,
@@ -420,10 +419,6 @@ impl DeleteTimelineFlow {
         Ok(())
     }
 
-    pub(crate) fn is_finished(&self) -> bool {
-        matches!(self, Self::Finished)
-    }
-
     pub(crate) fn is_not_started(&self) -> bool {
         matches!(self, Self::NotStarted)
     }

pageserver/src/tenant/timeline/layer_manager.rs

@@ -227,7 +227,6 @@ impl LayerManager {
     }
 
     /// Called when a GC-compaction is completed.
-    #[cfg(test)]
     pub(crate) fn finish_gc_compaction(
         &mut self,
         compact_from: &[Layer],

pageserver/src/tenant/vectored_blob_io.rs

@@ -20,6 +20,7 @@ use std::num::NonZeroUsize;
 
 use bytes::BytesMut;
 use pageserver_api::key::Key;
+use tokio_epoll_uring::BoundedBuf;
 use utils::lsn::Lsn;
 use utils::vec_map::VecMap;
 
@@ -77,7 +78,7 @@ pub(crate) struct VectoredReadBuilder {
     start: u64,
     end: u64,
     blobs_at: VecMap<u64, BlobMeta>,
-    max_read_size: usize,
+    max_read_size: Option<usize>,
 }
 
 impl VectoredReadBuilder {
@@ -90,7 +91,7 @@ impl VectoredReadBuilder {
         start_offset: u64,
         end_offset: u64,
         meta: BlobMeta,
-        max_read_size: usize,
+        max_read_size: Option<usize>,
     ) -> Self {
         let mut blobs_at = VecMap::default();
         blobs_at
@@ -111,7 +112,13 @@ impl VectoredReadBuilder {
     pub(crate) fn extend(&mut self, start: u64, end: u64, meta: BlobMeta) -> VectoredReadExtended {
         tracing::trace!(start, end, "trying to extend");
         let size = (end - start) as usize;
-        if self.end == start && self.size() + size <= self.max_read_size {
+        if self.end == start && {
+            if let Some(max_read_size) = self.max_read_size {
+                self.size() + size <= max_read_size
+            } else {
+                true
+            }
+        } {
             self.end = end;
             self.blobs_at
                 .append(start, meta)
@@ -157,7 +164,7 @@ pub struct VectoredReadPlanner {
     // Arguments for previous blob passed into [`VectoredReadPlanner::handle`]
     prev: Option<(Key, Lsn, u64, BlobFlag)>,
 
-    max_read_size: usize,
+    max_read_size: Option<usize>,
 }
 
 impl VectoredReadPlanner {
@@ -165,7 +172,20 @@ impl VectoredReadPlanner {
         Self {
             blobs: BTreeMap::new(),
             prev: None,
-            max_read_size,
+            max_read_size: Some(max_read_size),
+        }
+    }
+
+    /// This function should *only* be used if the caller has a way to control the limit. e.g., in [`StreamingVectoredReadPlanner`],
+    /// it uses the vectored read planner to avoid duplicated logic on handling blob start/end, while expecting the vectored
+    /// read planner to give a single read to a continuous range of bytes in the image layer. Therefore, it does not need the
+    /// code path to split reads into chunks of `max_read_size`, and controls the read size itself.
+    #[cfg(test)]
+    pub(crate) fn new_caller_controlled_max_limit() -> Self {
+        Self {
+            blobs: BTreeMap::new(),
+            prev: None,
+            max_read_size: None,
         }
     }
 
@@ -297,8 +317,9 @@ impl<'a> VectoredBlobReader<'a> {
         );
         let buf = self
             .file
-            .read_exact_at_n(buf, read.start, read.size(), ctx)
-            .await?;
+            .read_exact_at(buf.slice(0..read.size()), read.start, ctx)
+            .await?
+            .into_inner();
 
         let blobs_at = read.blobs_at.as_slice();
         let start_offset = blobs_at.first().expect("VectoredRead is never empty").0;
@@ -354,6 +375,87 @@ impl<'a> VectoredBlobReader<'a> {
     }
 }
 
+/// Read planner used in [`crate::tenant::storage_layer::image_layer::ImageLayerIterator`]. It provides a streaming API for
+/// getting read blobs. It returns a batch when `handle` gets called and when the current key would exceed the read_size and
+/// max_cnt constraints. Underlying it uses [`VectoredReadPlanner`].
+#[cfg(test)]
+pub struct StreamingVectoredReadPlanner {
+    planner: VectoredReadPlanner,
+    /// Max read size per batch
+    max_read_size: u64,
+    /// Max item count per batch
+    max_cnt: usize,
+    /// The first offset of this batch
+    this_batch_first_offset: Option<u64>,
+    /// Size of the current batch
+    cnt: usize,
+}
+
+#[cfg(test)]
+impl StreamingVectoredReadPlanner {
+    pub fn new(max_read_size: u64, max_cnt: usize) -> Self {
+        assert!(max_cnt > 0);
+        assert!(max_read_size > 0);
+        Self {
+            // We want to have exactly one read syscall (plus several others for index lookup) for each `next_batch` call.
+            // Therefore, we enforce `self.max_read_size` by ourselves instead of using the VectoredReadPlanner's capability,
+            // to avoid splitting into two I/Os.
+            planner: VectoredReadPlanner::new_caller_controlled_max_limit(),
+            max_cnt,
+            max_read_size,
+            this_batch_first_offset: None,
+            cnt: 0,
+        }
+    }
+
+    fn emit(&mut self, this_batch_first_offset: u64) -> VectoredRead {
+        let planner = std::mem::replace(
+            &mut self.planner,
+            VectoredReadPlanner::new_caller_controlled_max_limit(),
+        );
+        self.this_batch_first_offset = Some(this_batch_first_offset);
+        self.cnt = 1;
+        let mut batch = planner.finish();
+        assert_eq!(batch.len(), 1, "should have exactly one read batch");
+        batch.pop().unwrap()
+    }
+
+    pub fn handle(
+        &mut self,
+        key: Key,
+        lsn: Lsn,
+        offset: u64,
+        flag: BlobFlag,
+    ) -> Option<VectoredRead> {
+        if let Some(begin_offset) = self.this_batch_first_offset {
+            // Each batch will have at least one item b/c `self.this_batch_first_offset` is set
+            // after one item gets processed
+            if offset - begin_offset > self.max_read_size {
+                self.planner.handle_range_end(offset); // End the current batch with the offset
+                let batch = self.emit(offset); // Produce a batch
+                self.planner.handle(key, lsn, offset, flag); // Add this key to the next batch
+                return Some(batch);
+            }
+        } else {
+            self.this_batch_first_offset = Some(offset)
+        }
+        if self.cnt >= self.max_cnt {
+            self.planner.handle_range_end(offset); // End the current batch with the offset
+            let batch = self.emit(offset); // Produce a batch
+            self.planner.handle(key, lsn, offset, flag); // Add this key to the next batch
+            return Some(batch);
+        }
+        self.planner.handle(key, lsn, offset, flag); // Add this key to the current batch
+        self.cnt += 1;
+        None
+    }
+
+    pub fn handle_range_end(&mut self, offset: u64) -> VectoredRead {
+        self.planner.handle_range_end(offset);
+        self.emit(offset)
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

pageserver/src/virtual_file.rs

@@ -13,7 +13,7 @@
 use crate::context::RequestContext;
 use crate::metrics::{StorageIoOperation, STORAGE_IO_SIZE, STORAGE_IO_TIME_METRIC};
 
-use crate::page_cache::PageWriteGuard;
+use crate::page_cache::{PageWriteGuard, PAGE_SZ};
 use crate::tenant::TENANTS_SEGMENT_NAME;
 use camino::{Utf8Path, Utf8PathBuf};
 use once_cell::sync::OnceCell;
@@ -48,6 +48,7 @@ pub(crate) mod owned_buffers_io {
     //! but for the time being we're proving out the primitives in the neon.git repo
     //! for faster iteration.
 
+    pub(crate) mod slice;
     pub(crate) mod write;
     pub(crate) mod util {
         pub(crate) mod size_tracking_writer;
@@ -143,16 +144,17 @@ struct SlotInner {
 /// Impl of [`tokio_epoll_uring::IoBuf`] and [`tokio_epoll_uring::IoBufMut`] for [`PageWriteGuard`].
 struct PageWriteGuardBuf {
     page: PageWriteGuard<'static>,
-    init_up_to: usize,
 }
 // Safety: the [`PageWriteGuard`] gives us exclusive ownership of the page cache slot,
 // and the location remains stable even if [`Self`] or the [`PageWriteGuard`] is moved.
+// Page cache pages are zero-initialized, so, wrt uninitialized memory we're good.
+// (Page cache tracks separately whether the contents are valid, see `PageWriteGuard::mark_valid`.)
 unsafe impl tokio_epoll_uring::IoBuf for PageWriteGuardBuf {
     fn stable_ptr(&self) -> *const u8 {
         self.page.as_ptr()
     }
     fn bytes_init(&self) -> usize {
-        self.init_up_to
+        self.page.len()
     }
     fn bytes_total(&self) -> usize {
         self.page.len()
@@ -166,8 +168,8 @@ unsafe impl tokio_epoll_uring::IoBufMut for PageWriteGuardBuf {
     }
 
     unsafe fn set_init(&mut self, pos: usize) {
+        // There shouldn't really be any reason to call this API since bytes_init() == bytes_total().
         assert!(pos <= self.page.len());
-        self.init_up_to = pos;
     }
 }
 
@@ -585,37 +587,37 @@ impl VirtualFile {
         Ok(self.pos)
     }
 
-    pub async fn read_exact_at<B>(
+    /// Read the file contents in range `offset..(offset + slice.bytes_total())` into `slice[0..slice.bytes_total()]`.
+    ///
+    /// The returned `Slice<Buf>` is equivalent to the input `slice`, i.e., it's the same view into the same buffer.
+    pub async fn read_exact_at<Buf>(
         &self,
-        buf: B,
+        slice: Slice<Buf>,
         offset: u64,
         ctx: &RequestContext,
-    ) -> Result<B, Error>
+    ) -> Result<Slice<Buf>, Error>
     where
-        B: IoBufMut + Send,
+        Buf: IoBufMut + Send,
     {
-        let (buf, res) = read_exact_at_impl(buf, offset, None, |buf, offset| {
-            self.read_at(buf, offset, ctx)
-        })
-        .await;
-        res.map(|()| buf)
-    }
+        let assert_we_return_original_bounds = if cfg!(debug_assertions) {
+            Some((slice.stable_ptr() as usize, slice.bytes_total()))
+        } else {
+            None
+        };
 
-    pub async fn read_exact_at_n<B>(
-        &self,
-        buf: B,
-        offset: u64,
-        count: usize,
-        ctx: &RequestContext,
-    ) -> Result<B, Error>
-    where
-        B: IoBufMut + Send,
-    {
-        let (buf, res) = read_exact_at_impl(buf, offset, Some(count), |buf, offset| {
-            self.read_at(buf, offset, ctx)
-        })
-        .await;
-        res.map(|()| buf)
+        let original_bounds = slice.bounds();
+        let (buf, res) =
+            read_exact_at_impl(slice, offset, |buf, offset| self.read_at(buf, offset, ctx)).await;
+        let res = res.map(|_| buf.slice(original_bounds));
+
+        if let Some(original_bounds) = assert_we_return_original_bounds {
+            if let Ok(slice) = &res {
+                let returned_bounds = (slice.stable_ptr() as usize, slice.bytes_total());
+                assert_eq!(original_bounds, returned_bounds);
+            }
+        }
+
+        res
     }
 
     /// Like [`Self::read_exact_at`] but for [`PageWriteGuard`].
@@ -625,13 +627,11 @@ impl VirtualFile {
         offset: u64,
         ctx: &RequestContext,
     ) -> Result<PageWriteGuard<'static>, Error> {
-        let buf = PageWriteGuardBuf {
-            page,
-            init_up_to: 0,
-        };
-        let res = self.read_exact_at(buf, offset, ctx).await;
-        res.map(|PageWriteGuardBuf { page, .. }| page)
-            .map_err(|e| Error::new(ErrorKind::Other, e))
+        let buf = PageWriteGuardBuf { page }.slice_full();
+        debug_assert_eq!(buf.bytes_total(), PAGE_SZ);
+        self.read_exact_at(buf, offset, ctx)
+            .await
+            .map(|slice| slice.into_inner().page)
     }
 
     // Copied from https://doc.rust-lang.org/1.72.0/src/std/os/unix/fs.rs.html#219-235
@@ -671,17 +671,27 @@ impl VirtualFile {
     }
 
     /// Writes `buf.slice(0..buf.bytes_init())`.
-    /// Returns the IoBuf that is underlying the BoundedBuf `buf`.
-    /// I.e., the returned value's `bytes_init()` method returns something different than the `bytes_init()` that was passed in.
-    /// It's quite brittle and easy to mis-use, so, we return the size in the Ok() variant.
-    pub async fn write_all<B: BoundedBuf<Buf = Buf>, Buf: IoBuf + Send>(
+    ///
+    /// The returned `Slice<Buf>` is equivalent to the input `slice`, i.e., it's the same view into the same buffer.
+    /// We also return the amount of written data in the `Ok()` variant (although we could also have encountered
+    /// before an `Err()`).
+    pub async fn write_all<Buf: IoBuf + Send>(
         &mut self,
-        buf: B,
+        buf: Slice<Buf>,
         ctx: &RequestContext,
-    ) -> (B::Buf, Result<usize, Error>) {
+    ) -> (Slice<Buf>, Result<usize, Error>) {
+        let begin_end = buf.bounds();
+
+        macro_rules! return_orig_bounds {
+            ($buf:expr, $val:expr) => {{
+                let buf = $buf.into_inner();
+                return (buf.slice(begin_end), $val);
+            }};
+        }
+
         let nbytes = buf.bytes_init();
         if nbytes == 0 {
-            return (Slice::into_inner(buf.slice_full()), Ok(0));
+            return (buf, Ok(0));
         }
         let mut buf = buf.slice(0..nbytes);
         while !buf.is_empty() {
@@ -689,22 +699,23 @@ impl VirtualFile {
             (buf, res) = self.write(buf, ctx).await;
             match res {
                 Ok(0) => {
-                    return (
-                        Slice::into_inner(buf),
+                    return_orig_bounds!(
+                        buf,
                         Err(Error::new(
                             std::io::ErrorKind::WriteZero,
                             "failed to write whole buffer",
-                        )),
+                        ))
                     );
                 }
                 Ok(n) => {
                     buf = buf.slice(n..);
                 }
                 Err(ref e) if e.kind() == std::io::ErrorKind::Interrupted => {}
-                Err(e) => return (Slice::into_inner(buf), Err(e)),
+                Err(e) => return_orig_bounds!(buf, Err(e)),
             }
         }
-        (Slice::into_inner(buf), Ok(nbytes))
+
+        return_orig_bounds!(buf, Ok(nbytes));
     }
 
     async fn write<B: IoBuf + Send>(
@@ -722,14 +733,14 @@ impl VirtualFile {
         (buf, Ok(n))
     }
 
-    pub(crate) async fn read_at<B>(
+    pub(crate) async fn read_at<Buf>(
         &self,
-        buf: B,
+        buf: tokio_epoll_uring::Slice<Buf>,
         offset: u64,
         _ctx: &RequestContext, /* TODO: use for metrics: https://github.com/neondatabase/neon/issues/6107 */
-    ) -> (B, Result<usize, Error>)
+    ) -> (tokio_epoll_uring::Slice<Buf>, Result<usize, Error>)
     where
-        B: tokio_epoll_uring::BoundedBufMut + Send,
+        Buf: tokio_epoll_uring::IoBufMut + Send,
     {
         let file_guard = match self.lock_file().await {
             Ok(file_guard) => file_guard,
@@ -781,26 +792,16 @@ impl VirtualFile {
 }
 
 // Adapted from https://doc.rust-lang.org/1.72.0/src/std/os/unix/fs.rs.html#117-135
-pub async fn read_exact_at_impl<B, F, Fut>(
-    buf: B,
+pub async fn read_exact_at_impl<Buf, F, Fut>(
+    mut buf: tokio_epoll_uring::Slice<Buf>,
     mut offset: u64,
-    count: Option<usize>,
     mut read_at: F,
-) -> (B, std::io::Result<()>)
+) -> (Buf, std::io::Result<()>)
 where
-    B: IoBufMut + Send,
-    F: FnMut(tokio_epoll_uring::Slice<B>, u64) -> Fut,
-    Fut: std::future::Future<Output = (tokio_epoll_uring::Slice<B>, std::io::Result<usize>)>,
+    Buf: IoBufMut + Send,
+    F: FnMut(tokio_epoll_uring::Slice<Buf>, u64) -> Fut,
+    Fut: std::future::Future<Output = (tokio_epoll_uring::Slice<Buf>, std::io::Result<usize>)>,
 {
-    let mut buf: tokio_epoll_uring::Slice<B> = match count {
-        Some(count) => {
-            assert!(count <= buf.bytes_total());
-            assert!(count > 0);
-            buf.slice(..count) // may include uninitialized memory
-        }
-        None => buf.slice_full(), // includes all the uninitialized memory
-    };
-
     while buf.bytes_total() != 0 {
         let res;
         (buf, res) = read_at(buf, offset).await;
@@ -882,7 +883,7 @@ mod test_read_exact_at_impl {
 
     #[tokio::test]
     async fn test_basic() {
-        let buf = Vec::with_capacity(5);
+        let buf = Vec::with_capacity(5).slice_full();
         let mock_read_at = Arc::new(tokio::sync::Mutex::new(MockReadAt {
             expectations: VecDeque::from(vec![Expectation {
                 offset: 0,
@@ -890,7 +891,7 @@ mod test_read_exact_at_impl {
                 result: Ok(vec![b'a', b'b', b'c', b'd', b'e']),
             }]),
         }));
-        let (buf, res) = read_exact_at_impl(buf, 0, None, |buf, offset| {
+        let (buf, res) = read_exact_at_impl(buf, 0, |buf, offset| {
             let mock_read_at = Arc::clone(&mock_read_at);
             async move { mock_read_at.lock().await.read_at(buf, offset).await }
         })
@@ -899,33 +900,13 @@ mod test_read_exact_at_impl {
         assert_eq!(buf, vec![b'a', b'b', b'c', b'd', b'e']);
     }
 
-    #[tokio::test]
-    async fn test_with_count() {
-        let buf = Vec::with_capacity(5);
-        let mock_read_at = Arc::new(tokio::sync::Mutex::new(MockReadAt {
-            expectations: VecDeque::from(vec![Expectation {
-                offset: 0,
-                bytes_total: 3,
-                result: Ok(vec![b'a', b'b', b'c']),
-            }]),
-        }));
-
-        let (buf, res) = read_exact_at_impl(buf, 0, Some(3), |buf, offset| {
-            let mock_read_at = Arc::clone(&mock_read_at);
-            async move { mock_read_at.lock().await.read_at(buf, offset).await }
-        })
-        .await;
-        assert!(res.is_ok());
-        assert_eq!(buf, vec![b'a', b'b', b'c']);
-    }
-
     #[tokio::test]
     async fn test_empty_buf_issues_no_syscall() {
-        let buf = Vec::new();
+        let buf = Vec::new().slice_full();
         let mock_read_at = Arc::new(tokio::sync::Mutex::new(MockReadAt {
             expectations: VecDeque::new(),
         }));
-        let (_buf, res) = read_exact_at_impl(buf, 0, None, |buf, offset| {
+        let (_buf, res) = read_exact_at_impl(buf, 0, |buf, offset| {
             let mock_read_at = Arc::clone(&mock_read_at);
             async move { mock_read_at.lock().await.read_at(buf, offset).await }
         })
@@ -935,7 +916,7 @@ mod test_read_exact_at_impl {
 
     #[tokio::test]
     async fn test_two_read_at_calls_needed_until_buf_filled() {
-        let buf = Vec::with_capacity(4);
+        let buf = Vec::with_capacity(4).slice_full();
         let mock_read_at = Arc::new(tokio::sync::Mutex::new(MockReadAt {
             expectations: VecDeque::from(vec![
                 Expectation {
@@ -950,7 +931,7 @@ mod test_read_exact_at_impl {
                 },
             ]),
         }));
-        let (buf, res) = read_exact_at_impl(buf, 0, None, |buf, offset| {
+        let (buf, res) = read_exact_at_impl(buf, 0, |buf, offset| {
             let mock_read_at = Arc::clone(&mock_read_at);
             async move { mock_read_at.lock().await.read_at(buf, offset).await }
         })
@@ -961,7 +942,7 @@ mod test_read_exact_at_impl {
 
     #[tokio::test]
     async fn test_eof_before_buffer_full() {
-        let buf = Vec::with_capacity(3);
+        let buf = Vec::with_capacity(3).slice_full();
         let mock_read_at = Arc::new(tokio::sync::Mutex::new(MockReadAt {
             expectations: VecDeque::from(vec![
                 Expectation {
@@ -981,7 +962,7 @@ mod test_read_exact_at_impl {
                 },
             ]),
         }));
-        let (_buf, res) = read_exact_at_impl(buf, 0, None, |buf, offset| {
+        let (_buf, res) = read_exact_at_impl(buf, 0, |buf, offset| {
             let mock_read_at = Arc::clone(&mock_read_at);
             async move { mock_read_at.lock().await.read_at(buf, offset).await }
         })
@@ -1051,27 +1032,29 @@ impl VirtualFile {
         ctx: &RequestContext,
     ) -> Result<crate::tenant::block_io::BlockLease<'_>, std::io::Error> {
         use crate::page_cache::PAGE_SZ;
-        let buf = vec![0; PAGE_SZ];
-        let buf = self
-            .read_exact_at(buf, blknum as u64 * (PAGE_SZ as u64), ctx)
+        let slice = Vec::with_capacity(PAGE_SZ).slice_full();
+        assert_eq!(slice.bytes_total(), PAGE_SZ);
+        let slice = self
+            .read_exact_at(slice, blknum as u64 * (PAGE_SZ as u64), ctx)
             .await?;
-        Ok(crate::tenant::block_io::BlockLease::Vec(buf))
+        Ok(crate::tenant::block_io::BlockLease::Vec(slice.into_inner()))
     }
 
     async fn read_to_end(&mut self, buf: &mut Vec<u8>, ctx: &RequestContext) -> Result<(), Error> {
         let mut tmp = vec![0; 128];
         loop {
-            let res;
-            (tmp, res) = self.read_at(tmp, self.pos, ctx).await;
+            let slice = tmp.slice(..128);
+            let (slice, res) = self.read_at(slice, self.pos, ctx).await;
             match res {
                 Ok(0) => return Ok(()),
                 Ok(n) => {
                     self.pos += n as u64;
-                    buf.extend_from_slice(&tmp[..n]);
+                    buf.extend_from_slice(&slice[..n]);
                 }
                 Err(ref e) if e.kind() == std::io::ErrorKind::Interrupted => {}
                 Err(e) => return Err(e),
             }
+            tmp = slice.into_inner();
         }
     }
 }
@@ -1124,8 +1107,8 @@ impl OwnedAsyncWriter for VirtualFile {
         buf: B,
         ctx: &RequestContext,
     ) -> std::io::Result<(usize, B::Buf)> {
-        let (buf, res) = VirtualFile::write_all(self, buf, ctx).await;
-        res.map(move |v| (v, buf))
+        let (buf, res) = VirtualFile::write_all(self, buf.slice_full(), ctx).await;
+        res.map(move |v| (v, Slice::into_inner(buf)))
     }
 }
 
@@ -1185,6 +1168,7 @@ mod tests {
     use crate::task_mgr::TaskKind;
 
     use super::*;
+    use owned_buffers_io::slice::SliceExt;
     use rand::seq::SliceRandom;
     use rand::thread_rng;
     use rand::Rng;
@@ -1206,13 +1190,16 @@ mod tests {
     impl MaybeVirtualFile {
         async fn read_exact_at(
             &self,
-            mut buf: Vec<u8>,
+            mut slice: tokio_epoll_uring::Slice<Vec<u8>>,
             offset: u64,
             ctx: &RequestContext,
-        ) -> Result<Vec<u8>, Error> {
+        ) -> Result<tokio_epoll_uring::Slice<Vec<u8>>, Error> {
             match self {
-                MaybeVirtualFile::VirtualFile(file) => file.read_exact_at(buf, offset, ctx).await,
-                MaybeVirtualFile::File(file) => file.read_exact_at(&mut buf, offset).map(|()| buf),
+                MaybeVirtualFile::VirtualFile(file) => file.read_exact_at(slice, offset, ctx).await,
+                MaybeVirtualFile::File(file) => {
+                    let rust_slice: &mut [u8] = slice.as_mut_rust_slice_full_zeroed();
+                    file.read_exact_at(rust_slice, offset).map(|()| slice)
+                }
             }
         }
         async fn write_all_at<B: BoundedBuf<Buf = Buf>, Buf: IoBuf + Send>(
@@ -1241,9 +1228,9 @@ mod tests {
                 MaybeVirtualFile::File(file) => file.seek(pos),
             }
         }
-        async fn write_all<B: BoundedBuf<Buf = Buf>, Buf: IoBuf + Send>(
+        async fn write_all<Buf: IoBuf + Send>(
             &mut self,
-            buf: B,
+            buf: Slice<Buf>,
             ctx: &RequestContext,
         ) -> Result<(), Error> {
             match self {
@@ -1286,9 +1273,12 @@ mod tests {
             len: usize,
             ctx: &RequestContext,
         ) -> Result<String, Error> {
-            let buf = vec![0; len];
-            let buf = self.read_exact_at(buf, pos, ctx).await?;
-            Ok(String::from_utf8(buf).unwrap())
+            let slice = Vec::with_capacity(len).slice_full();
+            assert_eq!(slice.bytes_total(), len);
+            let slice = self.read_exact_at(slice, pos, ctx).await?;
+            let vec = slice.into_inner();
+            assert_eq!(vec.len(), len);
+            Ok(String::from_utf8(vec).unwrap())
         }
     }
 
@@ -1366,7 +1356,9 @@ mod tests {
             &ctx,
         )
         .await?;
-        file_a.write_all(b"foobar".to_vec(), &ctx).await?;
+        file_a
+            .write_all(b"foobar".to_vec().slice_full(), &ctx)
+            .await?;
 
         // cannot read from a file opened in write-only mode
         let _ = file_a.read_string(&ctx).await.unwrap_err();
@@ -1375,7 +1367,10 @@ mod tests {
         let mut file_a = A::open(path_a, OpenOptions::new().read(true).to_owned(), &ctx).await?;
 
         // cannot write to a file opened in read-only mode
-        let _ = file_a.write_all(b"bar".to_vec(), &ctx).await.unwrap_err();
+        let _ = file_a
+            .write_all(b"bar".to_vec().slice_full(), &ctx)
+            .await
+            .unwrap_err();
 
         // Try simple read
         assert_eq!("foobar", file_a.read_string(&ctx).await?);
@@ -1507,7 +1502,11 @@ mod tests {
                 let mut rng = rand::rngs::OsRng;
                 for _ in 1..1000 {
                     let f = &files[rng.gen_range(0..files.len())];
-                    buf = f.read_exact_at(buf, 0, &ctx).await.unwrap();
+                    buf = f
+                        .read_exact_at(buf.slice_full(), 0, &ctx)
+                        .await
+                        .unwrap()
+                        .into_inner();
                     assert!(buf == SAMPLE);
                 }
             });

pageserver/src/virtual_file/io_engine.rs

@@ -107,7 +107,7 @@ use std::{
     sync::atomic::{AtomicU8, Ordering},
 };
 
-use super::{FileGuard, Metadata};
+use super::{owned_buffers_io::slice::SliceExt, FileGuard, Metadata};
 
 #[cfg(target_os = "linux")]
 fn epoll_uring_error_to_std(e: tokio_epoll_uring::Error<std::io::Error>) -> std::io::Error {
@@ -120,38 +120,29 @@ fn epoll_uring_error_to_std(e: tokio_epoll_uring::Error<std::io::Error>) -> std:
 }
 
 impl IoEngine {
-    pub(super) async fn read_at<B>(
+    pub(super) async fn read_at<Buf>(
         &self,
         file_guard: FileGuard,
         offset: u64,
-        mut buf: B,
-    ) -> ((FileGuard, B), std::io::Result<usize>)
+        mut slice: tokio_epoll_uring::Slice<Buf>,
+    ) -> (
+        (FileGuard, tokio_epoll_uring::Slice<Buf>),
+        std::io::Result<usize>,
+    )
     where
-        B: tokio_epoll_uring::BoundedBufMut + Send,
+        Buf: tokio_epoll_uring::IoBufMut + Send,
     {
         match self {
             IoEngine::NotSet => panic!("not initialized"),
             IoEngine::StdFs => {
-                // SAFETY: `dst` only lives at most as long as this match arm, during which buf remains valid memory.
-                let dst = unsafe {
-                    std::slice::from_raw_parts_mut(buf.stable_mut_ptr(), buf.bytes_total())
-                };
-                let res = file_guard.with_std_file(|std_file| std_file.read_at(dst, offset));
-                if let Ok(nbytes) = &res {
-                    assert!(*nbytes <= buf.bytes_total());
-                    // SAFETY: see above assertion
-                    unsafe {
-                        buf.set_init(*nbytes);
-                    }
-                }
-                #[allow(dropping_references)]
-                drop(dst);
-                ((file_guard, buf), res)
+                let rust_slice = slice.as_mut_rust_slice_full_zeroed();
+                let res = file_guard.with_std_file(|std_file| std_file.read_at(rust_slice, offset));
+                ((file_guard, slice), res)
             }
             #[cfg(target_os = "linux")]
             IoEngine::TokioEpollUring => {
                 let system = tokio_epoll_uring_ext::thread_local_system().await;
-                let (resources, res) = system.read(file_guard, offset, buf).await;
+                let (resources, res) = system.read(file_guard, offset, slice).await;
                 (resources, res.map_err(epoll_uring_error_to_std))
             }
         }

pageserver/src/virtual_file/owned_buffers_io/slice.rs

@@ -0,0 +1,121 @@
+use tokio_epoll_uring::BoundedBuf;
+use tokio_epoll_uring::BoundedBufMut;
+use tokio_epoll_uring::IoBufMut;
+use tokio_epoll_uring::Slice;
+
+pub(crate) trait SliceExt {
+    /// Get a `&mut[0..self.bytes_total()`] slice, for when you need to do borrow-based IO.
+    ///
+    /// See the test case `test_slice_full_zeroed` for the difference to just doing `&slice[..]`
+    fn as_mut_rust_slice_full_zeroed(&mut self) -> &mut [u8];
+}
+
+impl<B> SliceExt for Slice<B>
+where
+    B: IoBufMut,
+{
+    #[inline(always)]
+    fn as_mut_rust_slice_full_zeroed(&mut self) -> &mut [u8] {
+        // zero-initialize the uninitialized parts of the buffer so we can create a Rust slice
+        //
+        // SAFETY: we own `slice`, don't write outside the bounds
+        unsafe {
+            let to_init = self.bytes_total() - self.bytes_init();
+            self.stable_mut_ptr()
+                .add(self.bytes_init())
+                .write_bytes(0, to_init);
+            self.set_init(self.bytes_total());
+        };
+        let bytes_total = self.bytes_total();
+        &mut self[0..bytes_total]
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use std::io::Read;
+
+    use super::*;
+    use bytes::Buf;
+    use tokio_epoll_uring::Slice;
+
+    #[test]
+    fn test_slice_full_zeroed() {
+        let make_fake_file = || bytes::BytesMut::from(&b"12345"[..]).reader();
+
+        // before we start the test, let's make sure we have a shared understanding of what slice_full does
+        {
+            let buf = Vec::with_capacity(3);
+            let slice: Slice<_> = buf.slice_full();
+            assert_eq!(slice.bytes_init(), 0);
+            assert_eq!(slice.bytes_total(), 3);
+            let rust_slice = &slice[..];
+            assert_eq!(
+                rust_slice.len(),
+                0,
+                "Slice only derefs to a &[u8] of the initialized part"
+            );
+        }
+
+        // and also let's establish a shared understanding of .slice()
+        {
+            let buf = Vec::with_capacity(3);
+            let slice: Slice<_> = buf.slice(0..2);
+            assert_eq!(slice.bytes_init(), 0);
+            assert_eq!(slice.bytes_total(), 2);
+            let rust_slice = &slice[..];
+            assert_eq!(
+                rust_slice.len(),
+                0,
+                "Slice only derefs to a &[u8] of the initialized part"
+            );
+        }
+
+        // the above leads to the easy mistake of using slice[..] for borrow-based IO like so:
+        {
+            let buf = Vec::with_capacity(3);
+            let mut slice: Slice<_> = buf.slice_full();
+            assert_eq!(slice[..].len(), 0);
+            let mut file = make_fake_file();
+            file.read_exact(&mut slice[..]).unwrap(); // one might think this reads 3 bytes but it reads 0
+            assert_eq!(&slice[..] as &[u8], &[][..] as &[u8]);
+        }
+
+        // With owned buffers IO like with VirtualFilem, you could totally
+        // pass in a `Slice` with bytes_init()=0 but bytes_total()=5
+        // and it will read 5 bytes into the slice, and return a slice that has bytes_init()=5.
+        {
+            // TODO: demo
+        }
+
+        //
+        // Ok, now that we have a shared understanding let's demo how to use the extension trait.
+        //
+
+        // slice_full()
+        {
+            let buf = Vec::with_capacity(3);
+            let mut slice: Slice<_> = buf.slice_full();
+            let rust_slice = slice.as_mut_rust_slice_full_zeroed();
+            assert_eq!(rust_slice.len(), 3);
+            assert_eq!(rust_slice, &[0, 0, 0]);
+            let mut file = make_fake_file();
+            file.read_exact(rust_slice).unwrap();
+            assert_eq!(rust_slice, b"123");
+            assert_eq!(&slice[..], b"123");
+        }
+
+        // .slice(..)
+        {
+            let buf = Vec::with_capacity(3);
+            let mut slice: Slice<_> = buf.slice(0..2);
+            let rust_slice = slice.as_mut_rust_slice_full_zeroed();
+            assert_eq!(rust_slice.len(), 2);
+            assert_eq!(rust_slice, &[0, 0]);
+            let mut file = make_fake_file();
+            file.read_exact(rust_slice).unwrap();
+            assert_eq!(rust_slice, b"12");
+            assert_eq!(&slice[..], b"12");
+        }
+    }
+}

pageserver/src/walingest.rs

@@ -343,7 +343,33 @@ impl WalIngest {
                         xlog_checkpoint.oldestActiveXid,
                         self.checkpoint.oldestActiveXid
                     );
-                    self.checkpoint.oldestActiveXid = xlog_checkpoint.oldestActiveXid;
+
+                    // A shutdown checkpoint has `oldestActiveXid == InvalidTransactionid`,
+                    // because at shutdown, all in-progress transactions will implicitly
+                    // end. Postgres startup code knows that, and allows hot standby to start
+                    // immediately from a shutdown checkpoint.
+                    //
+                    // In Neon, Postgres hot standby startup always behaves as if starting from
+                    // an online checkpoint. It needs a valid `oldestActiveXid` value, so
+                    // instead of overwriting self.checkpoint.oldestActiveXid with
+                    // InvalidTransactionid from the checkpoint WAL record, update it to a
+                    // proper value, knowing that there are no in-progress transactions at this
+                    // point, except for prepared transactions.
+                    //
+                    // See also the neon code changes in the InitWalRecovery() function.
+                    if xlog_checkpoint.oldestActiveXid == pg_constants::INVALID_TRANSACTION_ID
+                        && info == pg_constants::XLOG_CHECKPOINT_SHUTDOWN
+                    {
+                        let mut oldest_active_xid = self.checkpoint.nextXid.value as u32;
+                        for xid in modification.tline.list_twophase_files(lsn, ctx).await? {
+                            if (xid.wrapping_sub(oldest_active_xid) as i32) < 0 {
+                                oldest_active_xid = xid;
+                            }
+                        }
+                        self.checkpoint.oldestActiveXid = oldest_active_xid;
+                    } else {
+                        self.checkpoint.oldestActiveXid = xlog_checkpoint.oldestActiveXid;
+                    }
 
                     // Write a new checkpoint key-value pair on every checkpoint record, even
                     // if nothing really changed. Not strictly required, but it seems nice to
@@ -375,6 +401,7 @@ impl WalIngest {
                 if info == pg_constants::XLOG_RUNNING_XACTS {
                     let xlrec = crate::walrecord::XlRunningXacts::decode(&mut buf);
                     self.checkpoint.oldestActiveXid = xlrec.oldest_running_xid;
+                    self.checkpoint_modified = true;
                 }
             }
             pg_constants::RM_REPLORIGIN_ID => {
@@ -1277,13 +1304,10 @@ impl WalIngest {
             xlrec.pageno, xlrec.oldest_xid, xlrec.oldest_xid_db
         );
 
-        // Here we treat oldestXid and oldestXidDB
-        // differently from postgres redo routines.
-        // In postgres checkpoint.oldestXid lags behind xlrec.oldest_xid
-        // until checkpoint happens and updates the value.
-        // Here we can use the most recent value.
-        // It's just an optimization, though and can be deleted.
-        // TODO Figure out if there will be any issues with replica.
+        // In Postgres, oldestXid and oldestXidDB are updated in memory when the CLOG is
+        // truncated, but a checkpoint record with the updated values isn't written until
+        // later. In Neon, a server can start at any LSN, not just on a checkpoint record,
+        // so we keep the oldestXid and oldestXidDB up-to-date.
         self.checkpoint.oldestXid = xlrec.oldest_xid;
         self.checkpoint.oldestXidDB = xlrec.oldest_xid_db;
         self.checkpoint_modified = true;
@@ -1384,14 +1408,31 @@ impl WalIngest {
             // Note: The multixact members can wrap around, even within one WAL record.
             offset = offset.wrapping_add(n_this_page as u32);
         }
-        if xlrec.mid >= self.checkpoint.nextMulti {
-            self.checkpoint.nextMulti = xlrec.mid + 1;
-            self.checkpoint_modified = true;
-        }
-        if xlrec.moff + xlrec.nmembers > self.checkpoint.nextMultiOffset {
-            self.checkpoint.nextMultiOffset = xlrec.moff + xlrec.nmembers;
+        let next_offset = offset;
+        assert!(xlrec.moff.wrapping_add(xlrec.nmembers) == next_offset);
+
+        // Update next-multi-xid and next-offset
+        //
+        // NB: In PostgreSQL, the next-multi-xid stored in the control file is allowed to
+        // go to 0, and it's fixed up by skipping to FirstMultiXactId in functions that
+        // read it, like GetNewMultiXactId(). This is different from how nextXid is
+        // incremented! nextXid skips over < FirstNormalTransactionId when the the value
+        // is stored, so it's never 0 in a checkpoint.
+        //
+        // I don't know why it's done that way, it seems less error-prone to skip over 0
+        // when the value is stored rather than when it's read. But let's do it the same
+        // way here.
+        let next_multi_xid = xlrec.mid.wrapping_add(1);
+
+        if self
+            .checkpoint
+            .update_next_multixid(next_multi_xid, next_offset)
+        {
             self.checkpoint_modified = true;
         }
+
+        // Also update the next-xid with the highest member. According to the comments in
+        // multixact_redo(), this shouldn't be necessary, but let's do the same here.
         let max_mbr_xid = xlrec.members.iter().fold(None, |acc, mbr| {
             if let Some(max_xid) = acc {
                 if mbr.xid.wrapping_sub(max_xid) as i32 > 0 {

pageserver/src/walredo.rs

@@ -40,6 +40,7 @@ use std::time::Duration;
 use std::time::Instant;
 use tracing::*;
 use utils::lsn::Lsn;
+use utils::sync::gate::GateError;
 use utils::sync::heavier_once_cell;
 
 ///
@@ -53,10 +54,18 @@ pub struct PostgresRedoManager {
     tenant_shard_id: TenantShardId,
     conf: &'static PageServerConf,
     last_redo_at: std::sync::Mutex<Option<Instant>>,
-    /// The current [`process::WalRedoProcess`] that is used by new redo requests.
-    /// We use [`heavier_once_cell`] for coalescing the spawning, but the redo
-    /// requests don't use the [`heavier_once_cell::Guard`] to keep ahold of the
+    /// We use [`heavier_once_cell`] for
+    ///
+    /// 1. coalescing the lazy spawning of walredo processes ([`ProcessOnceCell::Spawned`])
+    /// 2. prevent new processes from being spawned on [`Self::shutdown`] (=> [`ProcessOnceCell::ManagerShutDown`]).
+    ///
+    /// # Spawning
+    ///
+    /// Redo requests use the once cell to coalesce onto one call to [`process::WalRedoProcess::launch`].
+    ///
+    /// Notably, requests don't use the [`heavier_once_cell::Guard`] to keep ahold of the
     /// their process object; we use [`Arc::clone`] for that.
+    ///
     /// This is primarily because earlier implementations that didn't  use [`heavier_once_cell`]
     /// had that behavior; it's probably unnecessary.
     /// The only merit of it is that if one walredo process encounters an error,
@@ -65,7 +74,63 @@ pub struct PostgresRedoManager {
     /// still be using the old redo process. But, those other tasks will most likely
     /// encounter an error as well, and errors are an unexpected condition anyway.
     /// So, probably we could get rid of the `Arc` in the future.
-    redo_process: heavier_once_cell::OnceCell<Arc<process::WalRedoProcess>>,
+    ///
+    /// # Shutdown
+    ///
+    /// See [`Self::launched_processes`].
+    redo_process: heavier_once_cell::OnceCell<ProcessOnceCell>,
+
+    /// Gate that is entered when launching a walredo process and held open
+    /// until the process has been `kill()`ed and `wait()`ed upon.
+    ///
+    /// Manager shutdown waits for this gate to close after setting the
+    /// [`ProcessOnceCell::ManagerShutDown`] state in [`Self::redo_process`].
+    ///
+    /// This type of usage is a bit unusual because gates usually keep track of
+    /// concurrent operations, e.g., every [`Self::request_redo`] that is inflight.
+    /// But we use it here to keep track of the _processes_ that we have launched,
+    /// which may outlive any individual redo request because
+    /// - we keep walredo process around until its quiesced to amortize spawn cost and
+    /// - the Arc may be held by multiple concurrent redo requests, so, just because
+    ///   you replace the [`Self::redo_process`] cell's content doesn't mean the
+    ///   process gets killed immediately.
+    ///
+    /// We could simplify this by getting rid of the [`Arc`].
+    /// See the comment on [`Self::redo_process`] for more details.
+    launched_processes: utils::sync::gate::Gate,
+}
+
+/// See [`PostgresRedoManager::redo_process`].
+enum ProcessOnceCell {
+    Spawned(Arc<Process>),
+    ManagerShutDown,
+}
+
+struct Process {
+    _launched_processes_guard: utils::sync::gate::GateGuard,
+    process: process::WalRedoProcess,
+}
+
+impl std::ops::Deref for Process {
+    type Target = process::WalRedoProcess;
+
+    fn deref(&self) -> &Self::Target {
+        &self.process
+    }
+}
+
+#[derive(Debug, thiserror::Error)]
+pub enum Error {
+    #[error("cancelled")]
+    Cancelled,
+    #[error(transparent)]
+    Other(#[from] anyhow::Error),
+}
+
+macro_rules! bail {
+    ($($arg:tt)*) => {
+        return Err($crate::walredo::Error::Other(::anyhow::anyhow!($($arg)*)));
+    }
 }
 
 ///
@@ -88,9 +153,9 @@ impl PostgresRedoManager {
         base_img: Option<(Lsn, Bytes)>,
         records: Vec<(Lsn, NeonWalRecord)>,
         pg_version: u32,
-    ) -> anyhow::Result<Bytes> {
+    ) -> Result<Bytes, Error> {
         if records.is_empty() {
-            anyhow::bail!("invalid WAL redo request with no records");
+            bail!("invalid WAL redo request with no records");
         }
 
         let base_img_lsn = base_img.as_ref().map(|p| p.0).unwrap_or(Lsn::INVALID);
@@ -148,10 +213,10 @@ impl PostgresRedoManager {
                     chrono::Utc::now().checked_sub_signed(chrono::Duration::from_std(age).ok()?)
                 })
             },
-            process: self
-                .redo_process
-                .get()
-                .map(|p| WalRedoManagerProcessStatus { pid: p.id() }),
+            process: self.redo_process.get().and_then(|p| match &*p {
+                ProcessOnceCell::Spawned(p) => Some(WalRedoManagerProcessStatus { pid: p.id() }),
+                ProcessOnceCell::ManagerShutDown => None,
+            }),
         }
     }
 }
@@ -170,9 +235,39 @@ impl PostgresRedoManager {
             conf,
             last_redo_at: std::sync::Mutex::default(),
             redo_process: heavier_once_cell::OnceCell::default(),
+            launched_processes: utils::sync::gate::Gate::default(),
         }
     }
 
+    /// Shut down the WAL redo manager.
+    ///
+    /// After this future completes
+    /// - no redo process is running
+    /// - no new redo process will be spawned
+    /// - redo requests that need walredo process will fail with [`Error::Cancelled`]
+    /// - [`apply_neon`]-only redo requests may still work, but this may change in the future
+    ///
+    /// # Cancel-Safety
+    ///
+    /// This method is cancellation-safe.
+    pub async fn shutdown(&self) {
+        // prevent new processes from being spawned
+        let permit = match self.redo_process.get_or_init_detached().await {
+            Ok(guard) => {
+                let (proc, permit) = guard.take_and_deinit();
+                drop(proc); // this just drops the Arc, its refcount may not be zero yet
+                permit
+            }
+            Err(permit) => permit,
+        };
+        self.redo_process
+            .set(ProcessOnceCell::ManagerShutDown, permit);
+        // wait for ongoing requests to drain and the refcounts of all Arc<WalRedoProcess> that
+        // we ever launched to drop to zero, which when it happens synchronously kill()s & wait()s
+        // for the underlying process.
+        self.launched_processes.close().await;
+    }
+
     /// This type doesn't have its own background task to check for idleness: we
     /// rely on our owner calling this function periodically in its own housekeeping
     /// loops.
@@ -203,38 +298,48 @@ impl PostgresRedoManager {
         records: &[(Lsn, NeonWalRecord)],
         wal_redo_timeout: Duration,
         pg_version: u32,
-    ) -> anyhow::Result<Bytes> {
+    ) -> Result<Bytes, Error> {
         *(self.last_redo_at.lock().unwrap()) = Some(Instant::now());
 
         let (rel, blknum) = key.to_rel_block().context("invalid record")?;
         const MAX_RETRY_ATTEMPTS: u32 = 1;
         let mut n_attempts = 0u32;
         loop {
-            let proc: Arc<process::WalRedoProcess> =
-                match self.redo_process.get_or_init_detached().await {
-                    Ok(guard) => Arc::clone(&guard),
-                    Err(permit) => {
-                        // don't hold poison_guard, the launch code can bail
-                        let start = Instant::now();
-                        let proc = Arc::new(
-                            process::WalRedoProcess::launch(
+            let proc: Arc<Process> = match self.redo_process.get_or_init_detached().await {
+                Ok(guard) => match &*guard {
+                    ProcessOnceCell::Spawned(proc) => Arc::clone(proc),
+                    ProcessOnceCell::ManagerShutDown => {
+                        return Err(Error::Cancelled);
+                    }
+                },
+                Err(permit) => {
+                    let start = Instant::now();
+                    let proc = Arc::new(Process {
+                            _launched_processes_guard: match self.launched_processes.enter() {
+                                Ok(guard) => guard,
+                                Err(GateError::GateClosed) => unreachable!(
+                                    "shutdown sets the once cell to `ManagerShutDown` state before closing the gate"
+                                ),
+                            },
+                            process: process::WalRedoProcess::launch(
                                 self.conf,
                                 self.tenant_shard_id,
                                 pg_version,
                             )
                             .context("launch walredo process")?,
-                        );
-                        let duration = start.elapsed();
-                        WAL_REDO_PROCESS_LAUNCH_DURATION_HISTOGRAM.observe(duration.as_secs_f64());
-                        info!(
-                            duration_ms = duration.as_millis(),
-                            pid = proc.id(),
-                            "launched walredo process"
-                        );
-                        self.redo_process.set(Arc::clone(&proc), permit);
-                        proc
-                    }
-                };
+                        });
+                    let duration = start.elapsed();
+                    WAL_REDO_PROCESS_LAUNCH_DURATION_HISTOGRAM.observe(duration.as_secs_f64());
+                    info!(
+                        duration_ms = duration.as_millis(),
+                        pid = proc.id(),
+                        "launched walredo process"
+                    );
+                    self.redo_process
+                        .set(ProcessOnceCell::Spawned(Arc::clone(&proc)), permit);
+                    proc
+                }
+            };
 
             let started_at = std::time::Instant::now();
 
@@ -299,12 +404,17 @@ impl PostgresRedoManager {
                 match self.redo_process.get() {
                     None => (),
                     Some(guard) => {
-                        if Arc::ptr_eq(&proc, &*guard) {
-                            // We're the first to observe an error from `proc`, it's our job to take it out of rotation.
-                            guard.take_and_deinit();
-                        } else {
-                            // Another task already spawned another redo process (further up in this method)
-                            // and put it into `redo_process`. Do nothing, our view of the world is behind.
+                        match &*guard {
+                            ProcessOnceCell::ManagerShutDown => {}
+                            ProcessOnceCell::Spawned(guard_proc) => {
+                                if Arc::ptr_eq(&proc, guard_proc) {
+                                    // We're the first to observe an error from `proc`, it's our job to take it out of rotation.
+                                    guard.take_and_deinit();
+                                } else {
+                                    // Another task already spawned another redo process (further up in this method)
+                                    // and put it into `redo_process`. Do nothing, our view of the world is behind.
+                                }
+                            }
                         }
                     }
                 }
@@ -315,7 +425,7 @@ impl PostgresRedoManager {
             }
             n_attempts += 1;
             if n_attempts > MAX_RETRY_ATTEMPTS || result.is_ok() {
-                return result;
+                return result.map_err(Error::Other);
             }
         }
     }
@@ -329,7 +439,7 @@ impl PostgresRedoManager {
         lsn: Lsn,
         base_img: Option<Bytes>,
         records: &[(Lsn, NeonWalRecord)],
-    ) -> anyhow::Result<Bytes> {
+    ) -> Result<Bytes, Error> {
         let start_time = Instant::now();
 
         let mut page = BytesMut::new();
@@ -338,7 +448,7 @@ impl PostgresRedoManager {
             page.extend_from_slice(&fpi[..]);
         } else {
             // All the current WAL record types that we can handle require a base image.
-            anyhow::bail!("invalid neon WAL redo request with no base image");
+            bail!("invalid neon WAL redo request with no base image");
         }
 
         // Apply all the WAL records in the batch

pgxn/neon/neon.c

@@ -12,6 +12,8 @@
 #include "fmgr.h"
 
 #include "miscadmin.h"
+#include "access/subtrans.h"
+#include "access/twophase.h"
 #include "access/xact.h"
 #include "access/xlog.h"
 #include "storage/buf_internals.h"
@@ -22,10 +24,12 @@
 #include "replication/logical.h"
 #include "replication/slot.h"
 #include "replication/walsender.h"
+#include "storage/proc.h"
 #include "storage/procsignal.h"
 #include "tcop/tcopprot.h"
 #include "funcapi.h"
 #include "access/htup_details.h"
+#include "utils/builtins.h"
 #include "utils/pg_lsn.h"
 #include "utils/guc.h"
 #include "utils/wait_event.h"
@@ -41,7 +45,6 @@ PG_MODULE_MAGIC;
 void		_PG_init(void);
 
 static int	logical_replication_max_snap_files = 300;
-bool primary_is_running = false;
 
 static void
 InitLogicalReplicationMonitor(void)
@@ -267,6 +270,293 @@ LogicalSlotsMonitorMain(Datum main_arg)
 	}
 }
 
+/*
+ * XXX: These private to procarray.c, but we need them here.
+ */
+#define PROCARRAY_MAXPROCS	(MaxBackends + max_prepared_xacts)
+#define TOTAL_MAX_CACHED_SUBXIDS \
+	((PGPROC_MAX_CACHED_SUBXIDS + 1) * PROCARRAY_MAXPROCS)
+
+/*
+ * Restore running-xact information by scanning the CLOG at startup.
+ *
+ * In PostgreSQL, a standby always has to wait for a running-xacts WAL record
+ * to arrive before it can start accepting queries. Furthermore, if there are
+ * transactions with too many subxids (> 64) open to fit in the in-memory
+ * subxids cache, the running-xacts record will be marked as "suboverflowed",
+ * and the standby will need to also wait for the currently in-progress
+ * transactions to finish.
+ *
+ * That's not great in PostgreSQL, because a hot standby does not necessary
+ * open up for queries immediately as you might expect. But it's worse in
+ * Neon: A standby in Neon doesn't need to start WAL replay from a checkpoint
+ * record; it can start at any LSN. Postgres arranges things so that there is
+ * a running-xacts record soon after every checkpoint record, but when you
+ * start from an arbitrary LSN, that doesn't help. If the primary is idle, or
+ * not running at all, it might never write a new running-xacts record,
+ * leaving the replica in a limbo where it can never start accepting queries.
+ *
+ * To mitigate that, we have an additional mechanism to find the running-xacts
+ * information: we scan the CLOG, making note of any XIDs not marked as
+ * committed or aborted. They are added to the Postgres known-assigned XIDs
+ * array by calling ProcArrayApplyRecoveryInfo() in the caller of this
+ * function.
+ *
+ * There is one big limitation with that mechanism: The size of the
+ * known-assigned XIDs is limited, so if there are a lot of in-progress XIDs,
+ * we have to give up. Furthermore, we don't know how many of the in-progress
+ * XIDs are subtransactions, and if we use up all the space in the
+ * known-assigned XIDs array for subtransactions, we might run out of space in
+ * the array later during WAL replay, causing the replica to shut down with
+ * "ERROR: too many KnownAssignedXids". The safe # of XIDs that we can add to
+ * the known-assigned array without risking that error later is very low,
+ * merely PGPROC_MAX_CACHED_SUBXIDS == 64, so we take our chances and use up
+ * to half of the known-assigned XIDs array for the subtransactions, even
+ * though that risks getting the error later.
+ *
+ * Note: It's OK if the recovered list of XIDs includes some transactions that
+ * have crashed in the primary, and hence will never commit. They will be seen
+ * as in-progress, until we see a new next running-acts record with an
+ * oldestActiveXid that invalidates them. That's how the known-assigned XIDs
+ * array always works.
+ *
+ * If scraping the CLOG doesn't succeed for some reason, like the subxid
+ * overflow, Postgres will fall back to waiting for a running-xacts record
+ * like usual.
+ *
+ * Returns true if a complete list of in-progress XIDs was scraped.
+ */
+static bool
+RestoreRunningXactsFromClog(CheckPoint *checkpoint, TransactionId **xids, int *nxids)
+{
+	TransactionId from;
+	TransactionId till;
+	int			max_xcnt;
+	TransactionId *prepared_xids = NULL;
+	int			n_prepared_xids;
+	TransactionId *restored_xids = NULL;
+	int			n_restored_xids;
+	int			next_prepared_idx;
+
+	Assert(*xids == NULL);
+
+	/*
+	 * If the checkpoint doesn't have a valid oldestActiveXid, bail out. We
+	 * don't know where to start the scan.
+	 *
+	 * This shouldn't happen, because the pageserver always maintains a valid
+	 * oldestActiveXid nowadays. Except when starting at an old point in time
+	 * that was ingested before the pageserver was taught to do that.
+	 */
+	if (!TransactionIdIsValid(checkpoint->oldestActiveXid))
+	{
+		elog(LOG, "cannot restore running-xacts from CLOG because oldestActiveXid is not set");
+		goto fail;
+	}
+
+	/*
+	 * We will scan the CLOG starting from the oldest active XID.
+	 *
+	 * In some corner cases, the oldestActiveXid from the last checkpoint
+	 * might already have been truncated from the CLOG. That is,
+	 * oldestActiveXid might be older than oldestXid. That's possible because
+	 * oldestActiveXid is only updated at checkpoints. After the last
+	 * checkpoint, the oldest transaction might have committed, and the CLOG
+	 * might also have been already truncated. So if oldestActiveXid is older
+	 * than oldestXid, start at oldestXid instead. (Otherwise we'd try to
+	 * access CLOG segments that have already been truncated away.)
+	 */
+	from = TransactionIdPrecedes(checkpoint->oldestXid, checkpoint->oldestActiveXid)
+		? checkpoint->oldestActiveXid : checkpoint->oldestXid;
+	till = XidFromFullTransactionId(checkpoint->nextXid);
+
+	/*
+	 * To avoid "too many KnownAssignedXids" error later during replay, we
+	 * limit number of collected transactions. This is a tradeoff: if we are
+	 * willing to consume more of the KnownAssignedXids space for the XIDs
+	 * now, that allows us to start up, but we might run out of space later.
+	 *
+	 * The size of the KnownAssignedXids array is TOTAL_MAX_CACHED_SUBXIDS,
+	 * which is (PGPROC_MAX_CACHED_SUBXIDS + 1) * PROCARRAY_MAXPROCS). In
+	 * PostgreSQL, that's always enough because the primary will always write
+	 * an XLOG_XACT_ASSIGNMENT record if a transaction has more than
+	 * PGPROC_MAX_CACHED_SUBXIDS subtransactions. Seeing that record allows
+	 * the standby to mark the XIDs in pg_subtrans and removing them from the
+	 * KnowingAssignedXids array.
+	 *
+	 * Here, we don't know which XIDs belong to subtransactions that have
+	 * already been WAL-logged with an XLOG_XACT_ASSIGNMENT record. If we
+	 * wanted to be totally safe and avoid the possibility of getting a "too
+	 * many KnownAssignedXids" error later, we would have to limit ourselves
+	 * to PGPROC_MAX_CACHED_SUBXIDS, which is not much. And that includes top
+	 * transaction IDs too, because we cannot distinguish between top
+	 * transaction IDs and subtransactions here.
+	 *
+	 * Somewhat arbitrarily, we use up to half of KnownAssignedXids. That
+	 * strikes a sensible balance between being useful, and risking a "too
+	 * many KnownAssignedXids" error later.
+	 */
+	max_xcnt = TOTAL_MAX_CACHED_SUBXIDS / 2;
+
+	/*
+	 * Collect XIDs of prepared transactions in an array. This includes only
+	 * their top-level XIDs. We assume that StandbyRecoverPreparedTransactions
+	 * has already been called, so we can find all the sub-transactions in
+	 * pg_subtrans.
+	 */
+	PrescanPreparedTransactions(&prepared_xids, &n_prepared_xids);
+	qsort(prepared_xids, n_prepared_xids, sizeof(TransactionId), xidLogicalComparator);
+
+	/*
+	 * Scan the CLOG, collecting in-progress XIDs into 'restored_xids'.
+	 */
+	elog(DEBUG1, "scanning CLOG between %u and %u for in-progress XIDs", from, till);
+	restored_xids = (TransactionId *) palloc(max_xcnt * sizeof(TransactionId));
+	n_restored_xids = 0;
+	next_prepared_idx = 0;
+	for (TransactionId xid = from; xid != till;)
+	{
+		XLogRecPtr	xidlsn;
+		XidStatus	xidstatus;
+
+		xidstatus = TransactionIdGetStatus(xid, &xidlsn);
+
+		/*
+		 * "Merge" the prepared transactions into the restored_xids array as
+		 * we go.  The prepared transactions array is sorted. This is mostly
+		 * a sanity check to ensure that all the prpeared transactions are
+		 * seen as in-progress. (There is a check after the loop that we didn't
+		 * miss any.)
+		 */
+		if (next_prepared_idx < n_prepared_xids && xid == prepared_xids[next_prepared_idx])
+		{
+			/*
+			 * This is a top-level transaction ID of a prepared transaction.
+			 * Include it in the array.
+			 */
+
+			/* sanity check */
+			if (xidstatus != TRANSACTION_STATUS_IN_PROGRESS)
+			{
+				elog(LOG, "prepared transaction %u has unexpected status %X, cannot restore running-xacts from CLOG",
+					 xid, xidstatus);
+				Assert(false);
+				goto fail;
+			}
+
+			elog(DEBUG1, "XID %u: was next prepared xact (%d / %d)", xid, next_prepared_idx, n_prepared_xids);
+			next_prepared_idx++;
+		}
+		else if (xidstatus == TRANSACTION_STATUS_COMMITTED)
+		{
+			elog(DEBUG1, "XID %u: was committed", xid);
+			goto skip;
+		}
+		else if (xidstatus == TRANSACTION_STATUS_ABORTED)
+		{
+			elog(DEBUG1, "XID %u: was aborted", xid);
+			goto skip;
+		}
+		else if (xidstatus == TRANSACTION_STATUS_IN_PROGRESS)
+		{
+			/*
+			 * In-progress transactions are included in the array.
+			 *
+			 * Except subtransactions of the prepared transactions. They are
+			 * already set in pg_subtrans, and hence don't need to be tracked
+			 * in the known-assigned XIDs array.
+			 */
+			if (n_prepared_xids > 0)
+			{
+				TransactionId parent = SubTransGetParent(xid);
+
+				if (TransactionIdIsValid(parent))
+				{
+					/*
+					 * This is a subtransaction belonging to a prepared
+					 * transaction.
+					 *
+					 * Sanity check that it is in the prepared XIDs array. It
+					 * should be, because StandbyRecoverPreparedTransactions
+					 * populated pg_subtrans, and no other XID should be set
+					 * in it yet. (This also relies on the fact that
+					 * StandbyRecoverPreparedTransactions sets the parent of
+					 * each subxid to point directly to the top-level XID,
+					 * rather than restoring the original subtransaction
+					 * hierarchy.)
+					 */
+					if (bsearch(&parent, prepared_xids, next_prepared_idx,
+								sizeof(TransactionId), xidLogicalComparator) == NULL)
+					{
+						elog(LOG, "sub-XID %u has unexpected parent %u, cannot restore running-xacts from CLOG",
+							 xid, parent);
+						Assert(false);
+						goto fail;
+					}
+					elog(DEBUG1, "XID %u: was a subtransaction of prepared xid %u", xid, parent);
+					goto skip;
+				}
+			}
+
+			/* include it in the array */
+			elog(DEBUG1, "XID %u: is in progress", xid);
+		}
+		else
+		{
+			/*
+			 * SUB_COMMITTED is a transient state used at commit. We don't
+			 * expect to see that here.
+			 */
+			elog(LOG, "XID %u has unexpected status %X in pg_xact, cannot restore running-xacts from CLOG",
+				 xid, xidstatus);
+			Assert(false);
+			goto fail;
+		}
+
+		if (n_restored_xids >= max_xcnt)
+		{
+			/*
+			 * Overflowed. We won't be able to install the RunningTransactions
+			 * snapshot.
+			 */
+			elog(LOG, "too many running xacts to restore from the CLOG; oldestXid=%u oldestActiveXid=%u nextXid %u",
+				 checkpoint->oldestXid, checkpoint->oldestActiveXid,
+				 XidFromFullTransactionId(checkpoint->nextXid));
+			goto fail;
+		}
+
+		restored_xids[n_restored_xids++] = xid;
+
+	skip:
+		TransactionIdAdvance(xid);
+		continue;
+	}
+
+	/* sanity check */
+	if (next_prepared_idx != n_prepared_xids)
+	{
+		elog(LOG, "prepared transaction ID %u was not visited in the CLOG scan, cannot restore running-xacts from CLOG",
+			 prepared_xids[next_prepared_idx]);
+		Assert(false);
+		goto fail;
+	}
+
+	elog(LOG, "restored %d running xacts by scanning the CLOG; oldestXid=%u oldestActiveXid=%u nextXid %u",
+		 n_restored_xids, checkpoint->oldestXid, checkpoint->oldestActiveXid, XidFromFullTransactionId(checkpoint->nextXid));
+	*nxids = n_restored_xids;
+	*xids = restored_xids;
+	return true;
+
+ fail:
+	*nxids = 0;
+	*xids = NULL;
+	if (restored_xids)
+		pfree(restored_xids);
+	if (prepared_xids)
+		pfree(prepared_xids);
+	return false;
+}
+
 void
 _PG_init(void)
 {
@@ -289,15 +579,8 @@ _PG_init(void)
 
 	pg_init_extension_server();
 
-	DefineCustomBoolVariable(
-		"neon.primary_is_running",
-		"true if the primary was running at replica startup. false otherwise",
-		NULL,
-		&primary_is_running,
-		false,
-		PGC_POSTMASTER,
-		0,
-		NULL, NULL, NULL);
+	restore_running_xacts_callback = RestoreRunningXactsFromClog;
+
 	/*
 	 * Important: This must happen after other parts of the extension are
 	 * loaded, otherwise any settings to GUCs that were set before the

pgxn/neon/walproposer.c

@@ -1447,7 +1447,7 @@ RecvAppendResponses(Safekeeper *sk)
 			 * core as this is kinda expected scenario.
 			 */
 			disable_core_dump();
-			wp_log(PANIC, "WAL acceptor %s:%s with term " INT64_FORMAT " rejected our request, our term " INT64_FORMAT "",
+			wp_log(PANIC, "WAL acceptor %s:%s with term " INT64_FORMAT " rejected our request, our term " INT64_FORMAT ", meaning another compute is running at the same time, and it conflicts with us",
 				   sk->host, sk->port,
 				   sk->appendResponse.term, wp->propTerm);
 		}

pgxn/neon/walproposer_pg.c

@@ -63,6 +63,8 @@ char	   *wal_acceptors_list = "";
 int			wal_acceptor_reconnect_timeout = 1000;
 int			wal_acceptor_connection_timeout = 10000;
 
+/* Set to true in the walproposer bgw. */
+static bool am_walproposer;
 static WalproposerShmemState *walprop_shared;
 static WalProposerConfig walprop_config;
 static XLogRecPtr sentPtr = InvalidXLogRecPtr;
@@ -76,6 +78,7 @@ static HotStandbyFeedback agg_hs_feedback;
 
 static void nwp_shmem_startup_hook(void);
 static void nwp_register_gucs(void);
+static void assign_neon_safekeepers(const char *newval, void *extra);
 static void nwp_prepare_shmem(void);
 static uint64 backpressure_lag_impl(void);
 static bool backpressure_throttling_impl(void);
@@ -111,7 +114,8 @@ init_walprop_config(bool syncSafekeepers)
 {
 	walprop_config.neon_tenant = neon_tenant;
 	walprop_config.neon_timeline = neon_timeline;
-	walprop_config.safekeepers_list = wal_acceptors_list;
+	/* WalProposerCreate scribbles directly on it, so pstrdup */
+	walprop_config.safekeepers_list = pstrdup(wal_acceptors_list);
 	walprop_config.safekeeper_reconnect_timeout = wal_acceptor_reconnect_timeout;
 	walprop_config.safekeeper_connection_timeout = wal_acceptor_connection_timeout;
 	walprop_config.wal_segment_size = wal_segment_size;
@@ -151,6 +155,7 @@ WalProposerMain(Datum main_arg)
 
 	init_walprop_config(false);
 	walprop_pg_init_bgworker();
+	am_walproposer = true;
 	walprop_pg_load_libpqwalreceiver();
 
 	wp = WalProposerCreate(&walprop_config, walprop_pg);
@@ -189,10 +194,10 @@ nwp_register_gucs(void)
 							   NULL,	/* long_desc */
 							   &wal_acceptors_list, /* valueAddr */
 							   "",	/* bootValue */
-							   PGC_POSTMASTER,
+							   PGC_SIGHUP,
 							   GUC_LIST_INPUT,	/* extensions can't use*
 												 * GUC_LIST_QUOTE */
-							   NULL, NULL, NULL);
+							   NULL, assign_neon_safekeepers, NULL);
 
 	DefineCustomIntVariable(
 							"neon.safekeeper_reconnect_timeout",
@@ -215,6 +220,33 @@ nwp_register_gucs(void)
 							NULL, NULL, NULL);
 }
 
+/*
+ * GUC assign_hook for neon.safekeepers. Restarts walproposer through FATAL if
+ * the list changed.
+ */
+static void
+assign_neon_safekeepers(const char *newval, void *extra)
+{
+	if (!am_walproposer)
+		return;
+
+	if (!newval) {
+		/* should never happen */
+		wpg_log(FATAL, "neon.safekeepers is empty");
+	}
+
+	/* 
+	 * TODO: restarting through FATAL is stupid and introduces 1s delay before
+	 * next bgw start. We should refactor walproposer to allow graceful exit and
+	 * thus remove this delay.
+	 */
+	if (strcmp(wal_acceptors_list, newval) != 0)
+	{
+		wpg_log(FATAL, "restarting walproposer to change safekeeper list from %s to %s",
+				wal_acceptors_list, newval);
+	}
+}
+
 /*  Check if we need to suspend inserts because of lagging replication. */
 static uint64
 backpressure_lag_impl(void)
@@ -363,7 +395,7 @@ walprop_register_bgworker(void)
 	snprintf(bgw.bgw_function_name, BGW_MAXLEN, "WalProposerMain");
 	snprintf(bgw.bgw_name, BGW_MAXLEN, "WAL proposer");
 	snprintf(bgw.bgw_type, BGW_MAXLEN, "WAL proposer");
-	bgw.bgw_restart_time = 5;
+	bgw.bgw_restart_time = 1;
 	bgw.bgw_notify_pid = 0;
 	bgw.bgw_main_arg = (Datum) 0;
 
@@ -1639,6 +1671,18 @@ walprop_pg_wait_event_set(WalProposer *wp, long timeout, Safekeeper **sk, uint32
 		late_cv_trigger = ConditionVariableCancelSleep();
 #endif
 
+	/*
+	 * Process config if requested. This restarts walproposer if safekeepers
+	 * list changed. Don't do that for sync-safekeepers because quite probably
+	 * it (re-reading config) won't work without some effort, and
+	 * sync-safekeepers should be quick to finish anyway.
+	 */
+	if (!wp->config->syncSafekeepers && ConfigReloadPending)
+	{
+		ConfigReloadPending = false;
+		ProcessConfigFile(PGC_SIGHUP);
+	}
+
 	/*
 	 * If wait is terminated by latch set (walsenders' latch is set on each
 	 * wal flush). (no need for pm death check due to WL_EXIT_ON_PM_DEATH)

pgxn/neon_test_utils/Makefile

@@ -7,7 +7,7 @@ OBJS = \
 	neontest.o
 
 EXTENSION = neon_test_utils
-DATA = neon_test_utils--1.1.sql
+DATA = neon_test_utils--1.2.sql
 PGFILEDESC = "neon_test_utils - helpers for neon testing and debugging"
 
 PG_CONFIG = pg_config

pgxn/neon_test_utils/neon_test_utils--1.2.sql

@@ -41,7 +41,7 @@ RETURNS bytea
 AS 'MODULE_PATHNAME', 'get_raw_page_at_lsn_ex'
 LANGUAGE C PARALLEL UNSAFE;
 
-CREATE FUNCTION neon_xlogflush(lsn pg_lsn)
+CREATE FUNCTION neon_xlogflush(lsn pg_lsn DEFAULT NULL)
 RETURNS VOID
 AS 'MODULE_PATHNAME', 'neon_xlogflush'
 LANGUAGE C PARALLEL UNSAFE;

pgxn/neon_test_utils/neon_test_utils.control

@@ -1,6 +1,6 @@
 # neon_test_utils extension
 comment = 'helpers for neon testing and debugging'
-default_version = '1.1'
+default_version = '1.2'
 module_pathname = '$libdir/neon_test_utils'
 relocatable = true
 trusted = true

pgxn/neon_test_utils/neontest.c

@@ -15,6 +15,7 @@
 #include "access/relation.h"
 #include "access/xact.h"
 #include "access/xlog.h"
+#include "access/xlog_internal.h"
 #include "catalog/namespace.h"
 #include "fmgr.h"
 #include "funcapi.h"
@@ -444,11 +445,46 @@ get_raw_page_at_lsn_ex(PG_FUNCTION_ARGS)
 
 /*
  * Directly calls XLogFlush(lsn) to flush WAL buffers.
+ *
+ * If 'lsn' is not specified (is NULL), flush all generated WAL.
  */
 Datum
 neon_xlogflush(PG_FUNCTION_ARGS)
 {
-	XLogRecPtr	lsn = PG_GETARG_LSN(0);
+	XLogRecPtr	lsn;
+
+	if (RecoveryInProgress())
+		ereport(ERROR,
+				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+				 errmsg("recovery is in progress"),
+				 errhint("cannot flush WAL during recovery.")));
+
+	if (!PG_ARGISNULL(0))
+		lsn = PG_GETARG_LSN(0);
+	else
+	{
+		lsn = GetXLogInsertRecPtr();
+
+		/*---
+		 * The LSN returned by GetXLogInsertRecPtr() is the position where the
+		 * next inserted record would begin. If the last record ended just at
+		 * the page boundary, the next record will begin after the page header
+		 * on the next page, and that's what GetXLogInsertRecPtr().returns,
+		 * but the page header has not been written yet. If we tried to flush
+		 * it, XLogFlush() would throw an error:
+		 *
+		 * ERROR : xlog flush request %X/%X is not satisfied --- flushed only to %X/%X
+		 *
+		 * To avoid that, if the insert position points to just after the page
+		 * header, back off to page boundary.
+		 */
+		if (lsn % XLOG_BLCKSZ == SizeOfXLogShortPHD &&
+			XLogSegmentOffset(lsn, wal_segment_size) > XLOG_BLCKSZ)
+			lsn -= SizeOfXLogShortPHD;
+		else if (lsn % XLOG_BLCKSZ == SizeOfXLogLongPHD &&
+				 XLogSegmentOffset(lsn, wal_segment_size) < XLOG_BLCKSZ)
+			lsn -= SizeOfXLogLongPHD;
+	}
 
 	XLogFlush(lsn);
 	PG_RETURN_VOID();

pgxn/neon_walredo/walredoproc.c

@@ -168,16 +168,15 @@ close_range_syscall(unsigned int start_fd, unsigned int count, unsigned int flag
 static void
 enter_seccomp_mode(void)
 {
-
 	/*
 	 * The pageserver process relies on us to close all the file descriptors
 	 * it potentially leaked to us, _before_ we start processing potentially dangerous
 	 * wal records. See the comment in the Rust code that launches this process.
 	 */
-	int err;
-	if (err = close_range_syscall(3, ~0U, 0)) {
-		ereport(FATAL, (errcode(ERRCODE_SYSTEM_ERROR), errmsg("seccomp: could not close files >= fd 3")));
-	}
+	if (close_range_syscall(3, ~0U, 0) != 0)
+		ereport(FATAL,
+				(errcode(ERRCODE_SYSTEM_ERROR),
+				 errmsg("seccomp: could not close files >= fd 3")));
 
 	PgSeccompRule syscalls[] =
 	{

proxy/src/bin/pg_sni_router.rs

@@ -10,7 +10,7 @@ use itertools::Itertools;
 use proxy::config::TlsServerEndPoint;
 use proxy::context::RequestMonitoring;
 use proxy::metrics::{Metrics, ThreadPoolMetrics};
-use proxy::proxy::{copy_bidirectional_client_compute, run_until_cancelled};
+use proxy::proxy::{copy_bidirectional_client_compute, run_until_cancelled, ErrorSource};
 use rustls::pki_types::PrivateKeyDer;
 use tokio::net::TcpListener;
 
@@ -286,7 +286,10 @@ async fn handle_client(
 
     // Starting from here we only proxy the client's traffic.
     info!("performing the proxy pass...");
-    let _ = copy_bidirectional_client_compute(&mut tls_stream, &mut client).await?;
 
-    Ok(())
+    match copy_bidirectional_client_compute(&mut tls_stream, &mut client).await {
+        Ok(_) => Ok(()),
+        Err(ErrorSource::Client(err)) => Err(err).context("client"),
+        Err(ErrorSource::Compute(err)) => Err(err).context("compute"),
+    }
 }

proxy/src/compute.rs

@@ -103,12 +103,8 @@ impl ConnCfg {
 
     /// Reuse password or auth keys from the other config.
     pub fn reuse_password(&mut self, other: Self) {
-        if let Some(password) = other.get_password() {
-            self.password(password);
-        }
-
-        if let Some(keys) = other.get_auth_keys() {
-            self.auth_keys(keys);
+        if let Some(password) = other.get_auth() {
+            self.auth(password);
         }
     }
 
@@ -124,48 +120,64 @@ impl ConnCfg {
 
     /// Apply startup message params to the connection config.
     pub fn set_startup_params(&mut self, params: &StartupMessageParams) {
-        // Only set `user` if it's not present in the config.
-        // Link auth flow takes username from the console's response.
-        if let (None, Some(user)) = (self.get_user(), params.get("user")) {
-            self.user(user);
-        }
-
-        // Only set `dbname` if it's not present in the config.
-        // Link auth flow takes dbname from the console's response.
-        if let (None, Some(dbname)) = (self.get_dbname(), params.get("database")) {
-            self.dbname(dbname);
-        }
-
-        // Don't add `options` if they were only used for specifying a project.
-        // Connection pools don't support `options`, because they affect backend startup.
-        if let Some(options) = filtered_options(params) {
-            self.options(&options);
-        }
-
-        if let Some(app_name) = params.get("application_name") {
-            self.application_name(app_name);
-        }
-
-        // TODO: This is especially ugly...
-        if let Some(replication) = params.get("replication") {
-            use tokio_postgres::config::ReplicationMode;
-            match replication {
-                "true" | "on" | "yes" | "1" => {
-                    self.replication_mode(ReplicationMode::Physical);
+        let mut client_encoding = false;
+        for (k, v) in params.iter() {
+            match k {
+                "user" => {
+                    // Only set `user` if it's not present in the config.
+                    // Link auth flow takes username from the console's response.
+                    if self.get_user().is_none() {
+                        self.user(v);
+                    }
                 }
                 "database" => {
-                    self.replication_mode(ReplicationMode::Logical);
+                    // Only set `dbname` if it's not present in the config.
+                    // Link auth flow takes dbname from the console's response.
+                    if self.get_dbname().is_none() {
+                        self.dbname(v);
+                    }
+                }
+                "options" => {
+                    // Don't add `options` if they were only used for specifying a project.
+                    // Connection pools don't support `options`, because they affect backend startup.
+                    if let Some(options) = filtered_options(v) {
+                        self.options(&options);
+                    }
+                }
+
+                // the special ones in tokio-postgres that we don't want being set by the user
+                "dbname" => {}
+                "password" => {}
+                "sslmode" => {}
+                "host" => {}
+                "port" => {}
+                "connect_timeout" => {}
+                "keepalives" => {}
+                "keepalives_idle" => {}
+                "keepalives_interval" => {}
+                "keepalives_retries" => {}
+                "target_session_attrs" => {}
+                "channel_binding" => {}
+                "max_backend_message_size" => {}
+
+                "client_encoding" => {
+                    client_encoding = true;
+                    // only error should be from bad null bytes,
+                    // but we've already checked for those.
+                    _ = self.param("client_encoding", v);
+                }
+
+                _ => {
+                    // only error should be from bad null bytes,
+                    // but we've already checked for those.
+                    _ = self.param(k, v);
                 }
-                _other => {}
             }
         }
-
-        // TODO: extend the list of the forwarded startup parameters.
-        // Currently, tokio-postgres doesn't allow us to pass
-        // arbitrary parameters, but the ones above are a good start.
-        //
-        // This and the reverse params problem can be better addressed
-        // in a bespoke connection machinery (a new library for that sake).
+        if !client_encoding {
+            // for compatibility since we removed it from tokio-postgres
+            self.param("client_encoding", "UTF8").unwrap();
+        }
     }
 }
 
@@ -338,10 +350,9 @@ impl ConnCfg {
 }
 
 /// Retrieve `options` from a startup message, dropping all proxy-secific flags.
-fn filtered_options(params: &StartupMessageParams) -> Option<String> {
+fn filtered_options(options: &str) -> Option<String> {
     #[allow(unstable_name_collisions)]
-    let options: String = params
-        .options_raw()?
+    let options: String = StartupMessageParams::parse_options_raw(options)
         .filter(|opt| parse_endpoint_param(opt).is_none() && neon_option(opt).is_none())
         .intersperse(" ") // TODO: use impl from std once it's stabilized
         .collect();
@@ -413,27 +424,23 @@ mod tests {
     #[test]
     fn test_filtered_options() {
         // Empty options is unlikely to be useful anyway.
-        let params = StartupMessageParams::new([("options", "")]);
-        assert_eq!(filtered_options(&params), None);
+        assert_eq!(filtered_options(""), None);
 
         // It's likely that clients will only use options to specify endpoint/project.
-        let params = StartupMessageParams::new([("options", "project=foo")]);
-        assert_eq!(filtered_options(&params), None);
+        let params = "project=foo";
+        assert_eq!(filtered_options(params), None);
 
         // Same, because unescaped whitespaces are no-op.
-        let params = StartupMessageParams::new([("options", " project=foo ")]);
-        assert_eq!(filtered_options(&params).as_deref(), None);
+        let params = " project=foo ";
+        assert_eq!(filtered_options(params), None);
 
-        let params = StartupMessageParams::new([("options", r"\  project=foo \ ")]);
-        assert_eq!(filtered_options(&params).as_deref(), Some(r"\  \ "));
+        let params = r"\  project=foo \ ";
+        assert_eq!(filtered_options(params).as_deref(), Some(r"\  \ "));
 
-        let params = StartupMessageParams::new([("options", "project = foo")]);
-        assert_eq!(filtered_options(&params).as_deref(), Some("project = foo"));
+        let params = "project = foo";
+        assert_eq!(filtered_options(params).as_deref(), Some("project = foo"));
 
-        let params = StartupMessageParams::new([(
-            "options",
-            "project = foo neon_endpoint_type:read_write   neon_lsn:0/2",
-        )]);
-        assert_eq!(filtered_options(&params).as_deref(), Some("project = foo"));
+        let params = "project = foo neon_endpoint_type:read_write   neon_lsn:0/2";
+        assert_eq!(filtered_options(params).as_deref(), Some("project = foo"));
     }
 }

proxy/src/console/messages.rs

@@ -5,7 +5,7 @@ use std::fmt::{self, Display};
 use crate::auth::IpPattern;
 
 use crate::intern::{BranchIdInt, EndpointIdInt, ProjectIdInt};
-use crate::proxy::retry::ShouldRetry;
+use crate::proxy::retry::CouldRetry;
 
 /// Generic error response with human-readable description.
 /// Note that we can't always present it to user as is.
@@ -64,45 +64,47 @@ impl Display for ConsoleError {
     }
 }
 
-impl ShouldRetry for ConsoleError {
+impl CouldRetry for ConsoleError {
     fn could_retry(&self) -> bool {
-        if self.status.is_none() || self.status.as_ref().unwrap().details.retry_info.is_none() {
-            // retry some temporary failures because the compute was in a bad state
-            // (bad request can be returned when the endpoint was in transition)
-            return match &self {
-                ConsoleError {
-                    http_status_code: http::StatusCode::BAD_REQUEST,
-                    ..
-                } => true,
-                // don't retry when quotas are exceeded
-                ConsoleError {
-                    http_status_code: http::StatusCode::UNPROCESSABLE_ENTITY,
-                    ref error,
-                    ..
-                } => !error.contains("compute time quota of non-primary branches is exceeded"),
-                // locked can be returned when the endpoint was in transition
-                // or when quotas are exceeded. don't retry when quotas are exceeded
-                ConsoleError {
-                    http_status_code: http::StatusCode::LOCKED,
-                    ref error,
-                    ..
-                } => {
-                    !error.contains("quota exceeded")
-                        && !error.contains("the limit for current plan reached")
-                }
-                _ => false,
-            };
+        // If the error message does not have a status,
+        // the error is unknown and probably should not retry automatically
+        let Some(status) = &self.status else {
+            return false;
+        };
+
+        // retry if the retry info is set.
+        if status.details.retry_info.is_some() {
+            return true;
         }
 
-        // retry if the response has a retry delay
-        if let Some(retry_info) = self
-            .status
-            .as_ref()
-            .and_then(|s| s.details.retry_info.as_ref())
-        {
-            retry_info.retry_delay_ms > 0
-        } else {
-            false
+        // if no retry info set, attempt to use the error code to guess the retry state.
+        let reason = status
+            .details
+            .error_info
+            .map_or(Reason::Unknown, |e| e.reason);
+        match reason {
+            // not a transitive error
+            Reason::RoleProtected => false,
+            // on retry, it will still not be found
+            Reason::ResourceNotFound
+            | Reason::ProjectNotFound
+            | Reason::EndpointNotFound
+            | Reason::BranchNotFound => false,
+            // we were asked to go away
+            Reason::RateLimitExceeded
+            | Reason::NonDefaultBranchComputeTimeExceeded
+            | Reason::ActiveTimeQuotaExceeded
+            | Reason::ComputeTimeQuotaExceeded
+            | Reason::WrittenDataQuotaExceeded
+            | Reason::DataTransferQuotaExceeded
+            | Reason::LogicalSizeQuotaExceeded => false,
+            // transitive error. control plane is currently busy
+            // but might be ready soon
+            Reason::RunningOperations => true,
+            Reason::ConcurrencyLimitReached => true,
+            Reason::LockAlreadyTaken => true,
+            // unknown error. better not retry it.
+            Reason::Unknown => false,
         }
     }
 }
@@ -121,7 +123,7 @@ pub struct Details {
     pub user_facing_message: Option<UserFacingMessage>,
 }
 
-#[derive(Debug, Deserialize)]
+#[derive(Copy, Clone, Debug, Deserialize)]
 pub struct ErrorInfo {
     pub reason: Reason,
     // Schema could also have `metadata` field, but it's not structured. Skip it for now.
@@ -129,30 +131,59 @@ pub struct ErrorInfo {
 
 #[derive(Clone, Copy, Debug, Deserialize, Default)]
 pub enum Reason {
+    /// RoleProtected indicates that the role is protected and the attempted operation is not permitted on protected roles.
     #[serde(rename = "ROLE_PROTECTED")]
     RoleProtected,
+    /// ResourceNotFound indicates that a resource (project, endpoint, branch, etc.) wasn't found,
+    /// usually due to the provided ID not being correct or because the subject doesn't have enough permissions to
+    /// access the requested resource.
+    /// Prefer a more specific reason if possible, e.g., ProjectNotFound, EndpointNotFound, etc.
     #[serde(rename = "RESOURCE_NOT_FOUND")]
     ResourceNotFound,
+    /// ProjectNotFound indicates that the project wasn't found, usually due to the provided ID not being correct,
+    /// or that the subject doesn't have enough permissions to access the requested project.
     #[serde(rename = "PROJECT_NOT_FOUND")]
     ProjectNotFound,
+    /// EndpointNotFound indicates that the endpoint wasn't found, usually due to the provided ID not being correct,
+    /// or that the subject doesn't have enough permissions to access the requested endpoint.
     #[serde(rename = "ENDPOINT_NOT_FOUND")]
     EndpointNotFound,
+    /// BranchNotFound indicates that the branch wasn't found, usually due to the provided ID not being correct,
+    /// or that the subject doesn't have enough permissions to access the requested branch.
     #[serde(rename = "BRANCH_NOT_FOUND")]
     BranchNotFound,
+    /// RateLimitExceeded indicates that the rate limit for the operation has been exceeded.
     #[serde(rename = "RATE_LIMIT_EXCEEDED")]
     RateLimitExceeded,
+    /// NonDefaultBranchComputeTimeExceeded indicates that the compute time quota of non-default branches has been
+    /// exceeded.
     #[serde(rename = "NON_PRIMARY_BRANCH_COMPUTE_TIME_EXCEEDED")]
-    NonPrimaryBranchComputeTimeExceeded,
+    NonDefaultBranchComputeTimeExceeded,
+    /// ActiveTimeQuotaExceeded indicates that the active time quota was exceeded.
     #[serde(rename = "ACTIVE_TIME_QUOTA_EXCEEDED")]
     ActiveTimeQuotaExceeded,
+    /// ComputeTimeQuotaExceeded indicates that the compute time quota was exceeded.
     #[serde(rename = "COMPUTE_TIME_QUOTA_EXCEEDED")]
     ComputeTimeQuotaExceeded,
+    /// WrittenDataQuotaExceeded indicates that the written data quota was exceeded.
     #[serde(rename = "WRITTEN_DATA_QUOTA_EXCEEDED")]
     WrittenDataQuotaExceeded,
+    /// DataTransferQuotaExceeded indicates that the data transfer quota was exceeded.
     #[serde(rename = "DATA_TRANSFER_QUOTA_EXCEEDED")]
     DataTransferQuotaExceeded,
+    /// LogicalSizeQuotaExceeded indicates that the logical size quota was exceeded.
     #[serde(rename = "LOGICAL_SIZE_QUOTA_EXCEEDED")]
     LogicalSizeQuotaExceeded,
+    /// RunningOperations indicates that the project already has some running operations
+    /// and scheduling of new ones is prohibited.
+    #[serde(rename = "RUNNING_OPERATIONS")]
+    RunningOperations,
+    /// ConcurrencyLimitReached indicates that the concurrency limit for an action was reached.
+    #[serde(rename = "CONCURRENCY_LIMIT_REACHED")]
+    ConcurrencyLimitReached,
+    /// LockAlreadyTaken indicates that the we attempted to take a lock that was already taken.
+    #[serde(rename = "LOCK_ALREADY_TAKEN")]
+    LockAlreadyTaken,
     #[default]
     #[serde(other)]
     Unknown,
@@ -170,7 +201,7 @@ impl Reason {
     }
 }
 
-#[derive(Debug, Deserialize)]
+#[derive(Copy, Clone, Debug, Deserialize)]
 pub struct RetryInfo {
     pub retry_delay_ms: u64,
 }

proxy/src/console/provider.rs

@@ -25,9 +25,9 @@ use tracing::info;
 
 pub mod errors {
     use crate::{
-        console::messages::{self, ConsoleError},
+        console::messages::{self, ConsoleError, Reason},
         error::{io_error, ReportableError, UserFacingError},
-        proxy::retry::ShouldRetry,
+        proxy::retry::CouldRetry,
     };
     use thiserror::Error;
 
@@ -76,21 +76,22 @@ pub mod errors {
                 ApiError::Console(e) => {
                     use crate::error::ErrorKind::*;
                     match e.get_reason() {
-                        crate::console::messages::Reason::RoleProtected => User,
-                        crate::console::messages::Reason::ResourceNotFound => User,
-                        crate::console::messages::Reason::ProjectNotFound => User,
-                        crate::console::messages::Reason::EndpointNotFound => User,
-                        crate::console::messages::Reason::BranchNotFound => User,
-                        crate::console::messages::Reason::RateLimitExceeded => ServiceRateLimit,
-                        crate::console::messages::Reason::NonPrimaryBranchComputeTimeExceeded => {
-                            User
-                        }
-                        crate::console::messages::Reason::ActiveTimeQuotaExceeded => User,
-                        crate::console::messages::Reason::ComputeTimeQuotaExceeded => User,
-                        crate::console::messages::Reason::WrittenDataQuotaExceeded => User,
-                        crate::console::messages::Reason::DataTransferQuotaExceeded => User,
-                        crate::console::messages::Reason::LogicalSizeQuotaExceeded => User,
-                        crate::console::messages::Reason::Unknown => match &e {
+                        Reason::RoleProtected => User,
+                        Reason::ResourceNotFound => User,
+                        Reason::ProjectNotFound => User,
+                        Reason::EndpointNotFound => User,
+                        Reason::BranchNotFound => User,
+                        Reason::RateLimitExceeded => ServiceRateLimit,
+                        Reason::NonDefaultBranchComputeTimeExceeded => User,
+                        Reason::ActiveTimeQuotaExceeded => User,
+                        Reason::ComputeTimeQuotaExceeded => User,
+                        Reason::WrittenDataQuotaExceeded => User,
+                        Reason::DataTransferQuotaExceeded => User,
+                        Reason::LogicalSizeQuotaExceeded => User,
+                        Reason::ConcurrencyLimitReached => ControlPlane,
+                        Reason::LockAlreadyTaken => ControlPlane,
+                        Reason::RunningOperations => ControlPlane,
+                        Reason::Unknown => match &e {
                             ConsoleError {
                                 http_status_code:
                                     http::StatusCode::NOT_FOUND | http::StatusCode::NOT_ACCEPTABLE,
@@ -128,7 +129,7 @@ pub mod errors {
         }
     }
 
-    impl ShouldRetry for ApiError {
+    impl CouldRetry for ApiError {
         fn could_retry(&self) -> bool {
             match self {
                 // retry some transport errors
@@ -239,6 +240,17 @@ pub mod errors {
             }
         }
     }
+
+    impl CouldRetry for WakeComputeError {
+        fn could_retry(&self) -> bool {
+            match self {
+                WakeComputeError::BadComputeAddress(_) => false,
+                WakeComputeError::ApiError(e) => e.could_retry(),
+                WakeComputeError::TooManyConnections => false,
+                WakeComputeError::TooManyConnectionAttempts(_) => false,
+            }
+        }
+    }
 }
 
 /// Auth secret which is managed by the cloud.

proxy/src/context/parquet.rs

@@ -543,7 +543,9 @@ mod tests {
         rx: impl Stream<Item = RequestData>,
     ) -> Vec<(u64, usize, i64)> {
         let remote_storage_config = RemoteStorageConfig {
-            storage: RemoteStorageKind::LocalFs(tmpdir.to_path_buf()),
+            storage: RemoteStorageKind::LocalFs {
+                local_path: tmpdir.to_path_buf(),
+            },
             timeout: std::time::Duration::from_secs(120),
         };
         let storage = GenericRemoteStorage::from_config(&remote_storage_config).unwrap();

proxy/src/proxy.rs

@@ -8,6 +8,7 @@ pub mod passthrough;
 pub mod retry;
 pub mod wake_compute;
 pub use copy_bidirectional::copy_bidirectional_client_compute;
+pub use copy_bidirectional::ErrorSource;
 
 use crate::{
     auth,
@@ -148,8 +149,11 @@ pub async fn task_main(
                     ctx.log_connect();
                     match p.proxy_pass().instrument(span.clone()).await {
                         Ok(()) => {}
-                        Err(e) => {
-                            error!(parent: &span, "per-client task finished with an error: {e:#}");
+                        Err(ErrorSource::Client(e)) => {
+                            error!(parent: &span, "per-client task finished with an IO error from the client: {e:#}");
+                        }
+                        Err(ErrorSource::Compute(e)) => {
+                            error!(parent: &span, "per-client task finished with an IO error from the compute: {e:#}");
                         }
                     }
                 }

proxy/src/proxy/connect_compute.rs

@@ -7,7 +7,7 @@ use crate::{
     error::ReportableError,
     metrics::{ConnectOutcome, ConnectionFailureKind, Metrics, RetriesMetricGroup, RetryType},
     proxy::{
-        retry::{retry_after, ShouldRetry},
+        retry::{retry_after, should_retry, CouldRetry},
         wake_compute::wake_compute,
     },
     Host,
@@ -17,6 +17,8 @@ use pq_proto::StartupMessageParams;
 use tokio::time;
 use tracing::{error, info, warn};
 
+use super::retry::ShouldRetryWakeCompute;
+
 const CONNECT_TIMEOUT: time::Duration = time::Duration::from_secs(2);
 
 /// If we couldn't connect, a cached connection info might be to blame
@@ -104,7 +106,7 @@ pub async fn connect_to_compute<M: ConnectMechanism, B: ComputeConnectBackend>(
     connect_to_compute_retry_config: RetryConfig,
 ) -> Result<M::Connection, M::Error>
 where
-    M::ConnectError: ShouldRetry + std::fmt::Debug,
+    M::ConnectError: CouldRetry + ShouldRetryWakeCompute + std::fmt::Debug,
     M::Error: From<WakeComputeError>,
 {
     let mut num_retries = 0;
@@ -139,10 +141,10 @@ where
 
     error!(error = ?err, "could not connect to compute node");
 
-    let node_info = if !node_info.cached() || !err.should_retry_database_address() {
+    let node_info = if !node_info.cached() || !err.should_retry_wake_compute() {
         // If we just recieved this from cplane and dodn't get it from cache, we shouldn't retry.
         // Do not need to retrieve a new node_info, just return the old one.
-        if !err.should_retry(num_retries, connect_to_compute_retry_config) {
+        if should_retry(&err, num_retries, connect_to_compute_retry_config) {
             Metrics::get().proxy.retries_metric.observe(
                 RetriesMetricGroup {
                     outcome: ConnectOutcome::Failed,
@@ -188,9 +190,8 @@ where
                 return Ok(res);
             }
             Err(e) => {
-                let retriable = e.should_retry(num_retries, connect_to_compute_retry_config);
-                if !retriable {
-                    error!(error = ?e, num_retries, retriable, "couldn't connect to compute node");
+                if !should_retry(&e, num_retries, connect_to_compute_retry_config) {
+                    error!(error = ?e, num_retries, retriable = false, "couldn't connect to compute node");
                     Metrics::get().proxy.retries_metric.observe(
                         RetriesMetricGroup {
                             outcome: ConnectOutcome::Failed,
@@ -200,9 +201,10 @@ where
                     );
                     return Err(e.into());
                 }
-                warn!(error = ?e, num_retries, retriable, "couldn't connect to compute node");
+
+                warn!(error = ?e, num_retries, retriable = true, "couldn't connect to compute node");
             }
-        }
+        };
 
         let wait_duration = retry_after(num_retries, connect_to_compute_retry_config);
         num_retries += 1;

proxy/src/proxy/copy_bidirectional.rs

@@ -13,12 +13,39 @@ enum TransferState {
     Done(u64),
 }
 
+#[derive(Debug)]
+pub enum ErrorDirection {
+    Read(io::Error),
+    Write(io::Error),
+}
+
+impl ErrorSource {
+    fn from_client(err: ErrorDirection) -> ErrorSource {
+        match err {
+            ErrorDirection::Read(client) => Self::Client(client),
+            ErrorDirection::Write(compute) => Self::Compute(compute),
+        }
+    }
+    fn from_compute(err: ErrorDirection) -> ErrorSource {
+        match err {
+            ErrorDirection::Write(client) => Self::Client(client),
+            ErrorDirection::Read(compute) => Self::Compute(compute),
+        }
+    }
+}
+
+#[derive(Debug)]
+pub enum ErrorSource {
+    Client(io::Error),
+    Compute(io::Error),
+}
+
 fn transfer_one_direction<A, B>(
     cx: &mut Context<'_>,
     state: &mut TransferState,
     r: &mut A,
     w: &mut B,
-) -> Poll<io::Result<u64>>
+) -> Poll<Result<u64, ErrorDirection>>
 where
     A: AsyncRead + AsyncWrite + Unpin + ?Sized,
     B: AsyncRead + AsyncWrite + Unpin + ?Sized,
@@ -32,7 +59,7 @@ where
                 *state = TransferState::ShuttingDown(count);
             }
             TransferState::ShuttingDown(count) => {
-                ready!(w.as_mut().poll_shutdown(cx))?;
+                ready!(w.as_mut().poll_shutdown(cx)).map_err(ErrorDirection::Write)?;
                 *state = TransferState::Done(*count);
             }
             TransferState::Done(count) => return Poll::Ready(Ok(*count)),
@@ -44,7 +71,7 @@ where
 pub async fn copy_bidirectional_client_compute<Client, Compute>(
     client: &mut Client,
     compute: &mut Compute,
-) -> Result<(u64, u64), std::io::Error>
+) -> Result<(u64, u64), ErrorSource>
 where
     Client: AsyncRead + AsyncWrite + Unpin + ?Sized,
     Compute: AsyncRead + AsyncWrite + Unpin + ?Sized,
@@ -54,9 +81,11 @@ where
 
     poll_fn(|cx| {
         let mut client_to_compute_result =
-            transfer_one_direction(cx, &mut client_to_compute, client, compute)?;
+            transfer_one_direction(cx, &mut client_to_compute, client, compute)
+                .map_err(ErrorSource::from_client)?;
         let mut compute_to_client_result =
-            transfer_one_direction(cx, &mut compute_to_client, compute, client)?;
+            transfer_one_direction(cx, &mut compute_to_client, compute, client)
+                .map_err(ErrorSource::from_compute)?;
 
         // Early termination checks from compute to client.
         if let TransferState::Done(_) = compute_to_client {
@@ -65,18 +94,20 @@ where
                 // Initiate shutdown
                 client_to_compute = TransferState::ShuttingDown(buf.amt);
                 client_to_compute_result =
-                    transfer_one_direction(cx, &mut client_to_compute, client, compute)?;
+                    transfer_one_direction(cx, &mut client_to_compute, client, compute)
+                        .map_err(ErrorSource::from_client)?;
             }
         }
 
-        // Early termination checks from compute to client.
+        // Early termination checks from client to compute.
         if let TransferState::Done(_) = client_to_compute {
             if let TransferState::Running(buf) = &compute_to_client {
                 info!("Client is done, terminate compute");
                 // Initiate shutdown
                 compute_to_client = TransferState::ShuttingDown(buf.amt);
                 compute_to_client_result =
-                    transfer_one_direction(cx, &mut compute_to_client, client, compute)?;
+                    transfer_one_direction(cx, &mut compute_to_client, compute, client)
+                        .map_err(ErrorSource::from_compute)?;
             }
         }
 
@@ -138,7 +169,7 @@ impl CopyBuffer {
         cx: &mut Context<'_>,
         mut reader: Pin<&mut R>,
         mut writer: Pin<&mut W>,
-    ) -> Poll<io::Result<usize>>
+    ) -> Poll<Result<usize, ErrorDirection>>
     where
         R: AsyncRead + ?Sized,
         W: AsyncWrite + ?Sized,
@@ -149,11 +180,11 @@ impl CopyBuffer {
                 // Top up the buffer towards full if we can read a bit more
                 // data - this should improve the chances of a large write
                 if !me.read_done && me.cap < me.buf.len() {
-                    ready!(me.poll_fill_buf(cx, reader.as_mut()))?;
+                    ready!(me.poll_fill_buf(cx, reader.as_mut())).map_err(ErrorDirection::Read)?;
                 }
                 Poll::Pending
             }
-            res => res,
+            res => res.map_err(ErrorDirection::Write),
         }
     }
 
@@ -162,7 +193,7 @@ impl CopyBuffer {
         cx: &mut Context<'_>,
         mut reader: Pin<&mut R>,
         mut writer: Pin<&mut W>,
-    ) -> Poll<io::Result<u64>>
+    ) -> Poll<Result<u64, ErrorDirection>>
     where
         R: AsyncRead + ?Sized,
         W: AsyncWrite + ?Sized,
@@ -176,12 +207,13 @@ impl CopyBuffer {
 
                 match self.poll_fill_buf(cx, reader.as_mut()) {
                     Poll::Ready(Ok(())) => (),
-                    Poll::Ready(Err(err)) => return Poll::Ready(Err(err)),
+                    Poll::Ready(Err(err)) => return Poll::Ready(Err(ErrorDirection::Read(err))),
                     Poll::Pending => {
                         // Try flushing when the reader has no progress to avoid deadlock
                         // when the reader depends on buffered writer.
                         if self.need_flush {
-                            ready!(writer.as_mut().poll_flush(cx))?;
+                            ready!(writer.as_mut().poll_flush(cx))
+                                .map_err(ErrorDirection::Write)?;
                             self.need_flush = false;
                         }
 
@@ -194,10 +226,10 @@ impl CopyBuffer {
             while self.pos < self.cap {
                 let i = ready!(self.poll_write_buf(cx, reader.as_mut(), writer.as_mut()))?;
                 if i == 0 {
-                    return Poll::Ready(Err(io::Error::new(
+                    return Poll::Ready(Err(ErrorDirection::Write(io::Error::new(
                         io::ErrorKind::WriteZero,
                         "write zero byte into writer",
-                    )));
+                    ))));
                 } else {
                     self.pos += i;
                     self.amt += i as u64;
@@ -216,7 +248,7 @@ impl CopyBuffer {
             // If we've written all the data and we've seen EOF, flush out the
             // data and finish the transfer.
             if self.pos == self.cap && self.read_done {
-                ready!(writer.as_mut().poll_flush(cx))?;
+                ready!(writer.as_mut().poll_flush(cx)).map_err(ErrorDirection::Write)?;
                 return Poll::Ready(Ok(self.amt));
             }
         }

proxy/src/proxy/passthrough.rs

@@ -10,13 +10,15 @@ use tokio::io::{AsyncRead, AsyncWrite};
 use tracing::info;
 use utils::measured_stream::MeasuredStream;
 
+use super::copy_bidirectional::ErrorSource;
+
 /// Forward bytes in both directions (client <-> compute).
 #[tracing::instrument(skip_all)]
 pub async fn proxy_pass(
     client: impl AsyncRead + AsyncWrite + Unpin,
     compute: impl AsyncRead + AsyncWrite + Unpin,
     aux: MetricsAuxInfo,
-) -> anyhow::Result<()> {
+) -> Result<(), ErrorSource> {
     let usage = USAGE_METRICS.register(Ids {
         endpoint_id: aux.endpoint_id,
         branch_id: aux.branch_id,
@@ -66,9 +68,11 @@ pub struct ProxyPassthrough<P, S> {
 }
 
 impl<P, S: AsyncRead + AsyncWrite + Unpin> ProxyPassthrough<P, S> {
-    pub async fn proxy_pass(self) -> anyhow::Result<()> {
+    pub async fn proxy_pass(self) -> Result<(), ErrorSource> {
         let res = proxy_pass(self.client, self.compute.stream, self.aux).await;
-        self.compute.cancel_closure.try_cancel_query().await?;
+        if let Err(err) = self.compute.cancel_closure.try_cancel_query().await {
+            tracing::error!(?err, "could not cancel the query in the database");
+        }
         res
     }
 }

proxy/src/proxy/retry.rs

@@ -2,20 +2,22 @@ use crate::{compute, config::RetryConfig};
 use std::{error::Error, io};
 use tokio::time;
 
-pub trait ShouldRetry {
+pub trait CouldRetry {
+    /// Returns true if the error could be retried
     fn could_retry(&self) -> bool;
-    fn should_retry(&self, num_retries: u32, config: RetryConfig) -> bool {
-        match self {
-            _ if num_retries >= config.max_retries => false,
-            err => err.could_retry(),
-        }
-    }
-    fn should_retry_database_address(&self) -> bool {
-        true
-    }
 }
 
-impl ShouldRetry for io::Error {
+pub trait ShouldRetryWakeCompute {
+    /// Returns true if we need to invalidate the cache for this node.
+    /// If false, we can continue retrying with the current node cache.
+    fn should_retry_wake_compute(&self) -> bool;
+}
+
+pub fn should_retry(err: &impl CouldRetry, num_retries: u32, config: RetryConfig) -> bool {
+    num_retries < config.max_retries && err.could_retry()
+}
+
+impl CouldRetry for io::Error {
     fn could_retry(&self) -> bool {
         use std::io::ErrorKind;
         matches!(
@@ -25,7 +27,7 @@ impl ShouldRetry for io::Error {
     }
 }
 
-impl ShouldRetry for tokio_postgres::error::DbError {
+impl CouldRetry for tokio_postgres::error::DbError {
     fn could_retry(&self) -> bool {
         use tokio_postgres::error::SqlState;
         matches!(
@@ -36,7 +38,9 @@ impl ShouldRetry for tokio_postgres::error::DbError {
                 | &SqlState::SQLCLIENT_UNABLE_TO_ESTABLISH_SQLCONNECTION,
         )
     }
-    fn should_retry_database_address(&self) -> bool {
+}
+impl ShouldRetryWakeCompute for tokio_postgres::error::DbError {
+    fn should_retry_wake_compute(&self) -> bool {
         use tokio_postgres::error::SqlState;
         // Here are errors that happens after the user successfully authenticated to the database.
         // TODO: there are pgbouncer errors that should be retried, but they are not listed here.
@@ -53,7 +57,7 @@ impl ShouldRetry for tokio_postgres::error::DbError {
     }
 }
 
-impl ShouldRetry for tokio_postgres::Error {
+impl CouldRetry for tokio_postgres::Error {
     fn could_retry(&self) -> bool {
         if let Some(io_err) = self.source().and_then(|x| x.downcast_ref()) {
             io::Error::could_retry(io_err)
@@ -63,29 +67,33 @@ impl ShouldRetry for tokio_postgres::Error {
             false
         }
     }
-    fn should_retry_database_address(&self) -> bool {
-        if let Some(io_err) = self.source().and_then(|x| x.downcast_ref()) {
-            io::Error::should_retry_database_address(io_err)
-        } else if let Some(db_err) = self.source().and_then(|x| x.downcast_ref()) {
-            tokio_postgres::error::DbError::should_retry_database_address(db_err)
+}
+impl ShouldRetryWakeCompute for tokio_postgres::Error {
+    fn should_retry_wake_compute(&self) -> bool {
+        if let Some(db_err) = self.source().and_then(|x| x.downcast_ref()) {
+            tokio_postgres::error::DbError::should_retry_wake_compute(db_err)
         } else {
+            // likely an IO error. Possible the compute has shutdown and the
+            // cache is stale.
             true
         }
     }
 }
 
-impl ShouldRetry for compute::ConnectionError {
+impl CouldRetry for compute::ConnectionError {
     fn could_retry(&self) -> bool {
         match self {
             compute::ConnectionError::Postgres(err) => err.could_retry(),
             compute::ConnectionError::CouldNotConnect(err) => err.could_retry(),
+            compute::ConnectionError::WakeComputeError(err) => err.could_retry(),
             _ => false,
         }
     }
-    fn should_retry_database_address(&self) -> bool {
+}
+impl ShouldRetryWakeCompute for compute::ConnectionError {
+    fn should_retry_wake_compute(&self) -> bool {
         match self {
-            compute::ConnectionError::Postgres(err) => err.should_retry_database_address(),
-            compute::ConnectionError::CouldNotConnect(err) => err.should_retry_database_address(),
+            compute::ConnectionError::Postgres(err) => err.should_retry_wake_compute(),
             // the cache entry was not checked for validity
             compute::ConnectionError::TooManyConnectionAttempts(_) => false,
             _ => true,

proxy/src/proxy/tests.rs

@@ -5,21 +5,21 @@ mod mitm;
 use std::time::Duration;
 
 use super::connect_compute::ConnectMechanism;
-use super::retry::ShouldRetry;
+use super::retry::CouldRetry;
 use super::*;
 use crate::auth::backend::{
     ComputeCredentialKeys, ComputeCredentials, ComputeUserInfo, MaybeOwned, TestBackend,
 };
 use crate::config::{CertResolver, RetryConfig};
 use crate::console::caches::NodeInfoCache;
-use crate::console::messages::{ConsoleError, MetricsAuxInfo};
+use crate::console::messages::{ConsoleError, Details, MetricsAuxInfo, Status};
 use crate::console::provider::{CachedAllowedIps, CachedRoleSecret, ConsoleBackend};
 use crate::console::{self, CachedNodeInfo, NodeInfo};
 use crate::error::ErrorKind;
-use crate::proxy::retry::retry_after;
 use crate::{http, sasl, scram, BranchId, EndpointId, ProjectId};
 use anyhow::{bail, Context};
 use async_trait::async_trait;
+use retry::{retry_after, ShouldRetryWakeCompute};
 use rstest::rstest;
 use rustls::pki_types;
 use tokio_postgres::config::SslMode;
@@ -438,11 +438,16 @@ impl std::fmt::Display for TestConnectError {
 
 impl std::error::Error for TestConnectError {}
 
-impl ShouldRetry for TestConnectError {
+impl CouldRetry for TestConnectError {
     fn could_retry(&self) -> bool {
         self.retryable
     }
 }
+impl ShouldRetryWakeCompute for TestConnectError {
+    fn should_retry_wake_compute(&self) -> bool {
+        true
+    }
+}
 
 #[async_trait]
 impl ConnectMechanism for TestConnectMechanism {
@@ -485,7 +490,7 @@ impl TestBackend for TestConnectMechanism {
             ConnectAction::Wake => Ok(helper_create_cached_node_info(self.cache)),
             ConnectAction::WakeFail => {
                 let err = console::errors::ApiError::Console(ConsoleError {
-                    http_status_code: http::StatusCode::FORBIDDEN,
+                    http_status_code: http::StatusCode::BAD_REQUEST,
                     error: "TEST".into(),
                     status: None,
                 });
@@ -496,7 +501,15 @@ impl TestBackend for TestConnectMechanism {
                 let err = console::errors::ApiError::Console(ConsoleError {
                     http_status_code: http::StatusCode::BAD_REQUEST,
                     error: "TEST".into(),
-                    status: None,
+                    status: Some(Status {
+                        code: "error".into(),
+                        message: "error".into(),
+                        details: Details {
+                            error_info: None,
+                            retry_info: Some(console::messages::RetryInfo { retry_delay_ms: 1 }),
+                            user_facing_message: None,
+                        },
+                    }),
                 });
                 assert!(err.could_retry());
                 Err(console::errors::WakeComputeError::ApiError(err))

proxy/src/proxy/wake_compute.rs

@@ -1,18 +1,16 @@
 use crate::config::RetryConfig;
-use crate::console::messages::ConsoleError;
+use crate::console::messages::{ConsoleError, Reason};
 use crate::console::{errors::WakeComputeError, provider::CachedNodeInfo};
 use crate::context::RequestMonitoring;
 use crate::metrics::{
     ConnectOutcome, ConnectionFailuresBreakdownGroup, Metrics, RetriesMetricGroup, RetryType,
     WakeupFailureKind,
 };
-use crate::proxy::retry::retry_after;
+use crate::proxy::retry::{retry_after, should_retry};
 use hyper1::StatusCode;
-use std::ops::ControlFlow;
 use tracing::{error, info, warn};
 
 use super::connect_compute::ComputeConnectBackend;
-use super::retry::ShouldRetry;
 
 pub async fn wake_compute<B: ComputeConnectBackend>(
     num_retries: &mut u32,
@@ -22,9 +20,8 @@ pub async fn wake_compute<B: ComputeConnectBackend>(
 ) -> Result<CachedNodeInfo, WakeComputeError> {
     let retry_type = RetryType::WakeCompute;
     loop {
-        let wake_res = api.wake_compute(ctx).await;
-        match handle_try_wake(wake_res, *num_retries, config) {
-            Err(e) => {
+        match api.wake_compute(ctx).await {
+            Err(e) if !should_retry(&e, *num_retries, config) => {
                 error!(error = ?e, num_retries, retriable = false, "couldn't wake compute node");
                 report_error(&e, false);
                 Metrics::get().proxy.retries_metric.observe(
@@ -36,11 +33,11 @@ pub async fn wake_compute<B: ComputeConnectBackend>(
                 );
                 return Err(e);
             }
-            Ok(ControlFlow::Continue(e)) => {
+            Err(e) => {
                 warn!(error = ?e, num_retries, retriable = true, "couldn't wake compute node");
                 report_error(&e, true);
             }
-            Ok(ControlFlow::Break(n)) => {
+            Ok(n) => {
                 Metrics::get().proxy.retries_metric.observe(
                     RetriesMetricGroup {
                         outcome: ConnectOutcome::Success,
@@ -63,70 +60,28 @@ pub async fn wake_compute<B: ComputeConnectBackend>(
     }
 }
 
-/// Attempts to wake up the compute node.
-/// * Returns Ok(Continue(e)) if there was an error waking but retries are acceptable
-/// * Returns Ok(Break(node)) if the wakeup succeeded
-/// * Returns Err(e) if there was an error
-pub fn handle_try_wake(
-    result: Result<CachedNodeInfo, WakeComputeError>,
-    num_retries: u32,
-    config: RetryConfig,
-) -> Result<ControlFlow<CachedNodeInfo, WakeComputeError>, WakeComputeError> {
-    match result {
-        Err(err) => match &err {
-            WakeComputeError::ApiError(api) if api.should_retry(num_retries, config) => {
-                Ok(ControlFlow::Continue(err))
-            }
-            _ => Err(err),
-        },
-        // Ready to try again.
-        Ok(new) => Ok(ControlFlow::Break(new)),
-    }
-}
-
 fn report_error(e: &WakeComputeError, retry: bool) {
     use crate::console::errors::ApiError;
     let kind = match e {
         WakeComputeError::BadComputeAddress(_) => WakeupFailureKind::BadComputeAddress,
         WakeComputeError::ApiError(ApiError::Transport(_)) => WakeupFailureKind::ApiTransportError,
         WakeComputeError::ApiError(ApiError::Console(e)) => match e.get_reason() {
-            crate::console::messages::Reason::RoleProtected => {
-                WakeupFailureKind::ApiConsoleBadRequest
-            }
-            crate::console::messages::Reason::ResourceNotFound => {
-                WakeupFailureKind::ApiConsoleBadRequest
-            }
-            crate::console::messages::Reason::ProjectNotFound => {
-                WakeupFailureKind::ApiConsoleBadRequest
-            }
-            crate::console::messages::Reason::EndpointNotFound => {
-                WakeupFailureKind::ApiConsoleBadRequest
-            }
-            crate::console::messages::Reason::BranchNotFound => {
-                WakeupFailureKind::ApiConsoleBadRequest
-            }
-            crate::console::messages::Reason::RateLimitExceeded => {
-                WakeupFailureKind::ApiConsoleLocked
-            }
-            crate::console::messages::Reason::NonPrimaryBranchComputeTimeExceeded => {
-                WakeupFailureKind::QuotaExceeded
-            }
-            crate::console::messages::Reason::ActiveTimeQuotaExceeded => {
-                WakeupFailureKind::QuotaExceeded
-            }
-            crate::console::messages::Reason::ComputeTimeQuotaExceeded => {
-                WakeupFailureKind::QuotaExceeded
-            }
-            crate::console::messages::Reason::WrittenDataQuotaExceeded => {
-                WakeupFailureKind::QuotaExceeded
-            }
-            crate::console::messages::Reason::DataTransferQuotaExceeded => {
-                WakeupFailureKind::QuotaExceeded
-            }
-            crate::console::messages::Reason::LogicalSizeQuotaExceeded => {
-                WakeupFailureKind::QuotaExceeded
-            }
-            crate::console::messages::Reason::Unknown => match e {
+            Reason::RoleProtected => WakeupFailureKind::ApiConsoleBadRequest,
+            Reason::ResourceNotFound => WakeupFailureKind::ApiConsoleBadRequest,
+            Reason::ProjectNotFound => WakeupFailureKind::ApiConsoleBadRequest,
+            Reason::EndpointNotFound => WakeupFailureKind::ApiConsoleBadRequest,
+            Reason::BranchNotFound => WakeupFailureKind::ApiConsoleBadRequest,
+            Reason::RateLimitExceeded => WakeupFailureKind::ApiConsoleLocked,
+            Reason::NonDefaultBranchComputeTimeExceeded => WakeupFailureKind::QuotaExceeded,
+            Reason::ActiveTimeQuotaExceeded => WakeupFailureKind::QuotaExceeded,
+            Reason::ComputeTimeQuotaExceeded => WakeupFailureKind::QuotaExceeded,
+            Reason::WrittenDataQuotaExceeded => WakeupFailureKind::QuotaExceeded,
+            Reason::DataTransferQuotaExceeded => WakeupFailureKind::QuotaExceeded,
+            Reason::LogicalSizeQuotaExceeded => WakeupFailureKind::QuotaExceeded,
+            Reason::ConcurrencyLimitReached => WakeupFailureKind::ApiConsoleLocked,
+            Reason::LockAlreadyTaken => WakeupFailureKind::ApiConsoleLocked,
+            Reason::RunningOperations => WakeupFailureKind::ApiConsoleLocked,
+            Reason::Unknown => match e {
                 ConsoleError {
                     http_status_code: StatusCode::LOCKED,
                     ref error,

proxy/src/serverless/backend.rs

@@ -16,7 +16,10 @@ use crate::{
     context::RequestMonitoring,
     error::{ErrorKind, ReportableError, UserFacingError},
     intern::EndpointIdInt,
-    proxy::{connect_compute::ConnectMechanism, retry::ShouldRetry},
+    proxy::{
+        connect_compute::ConnectMechanism,
+        retry::{CouldRetry, ShouldRetryWakeCompute},
+    },
     rate_limiter::EndpointRateLimiter,
     Host,
 };
@@ -179,7 +182,7 @@ impl UserFacingError for HttpConnError {
     }
 }
 
-impl ShouldRetry for HttpConnError {
+impl CouldRetry for HttpConnError {
     fn could_retry(&self) -> bool {
         match self {
             HttpConnError::ConnectionError(e) => e.could_retry(),
@@ -190,9 +193,11 @@ impl ShouldRetry for HttpConnError {
             HttpConnError::TooManyConnectionAttempts(_) => false,
         }
     }
-    fn should_retry_database_address(&self) -> bool {
+}
+impl ShouldRetryWakeCompute for HttpConnError {
+    fn should_retry_wake_compute(&self) -> bool {
         match self {
-            HttpConnError::ConnectionError(e) => e.should_retry_database_address(),
+            HttpConnError::ConnectionError(e) => e.should_retry_wake_compute(),
             // we never checked cache validity
             HttpConnError::TooManyConnectionAttempts(_) => false,
             _ => true,
@@ -231,6 +236,10 @@ impl ConnectMechanism for TokioMechanism {
             .dbname(&self.conn_info.dbname)
             .connect_timeout(timeout);
 
+        config
+            .param("client_encoding", "UTF8")
+            .expect("client encoding UTF8 is always valid");
+
         let pause = ctx.latency_timer.pause(crate::metrics::Waiting::Compute);
         let res = config.connect(tokio_postgres::NoTls).await;
         drop(pause);

proxy/src/serverless/sql_over_http.rs

@@ -202,6 +202,7 @@ fn get_conn_info(
             options = Some(NeonOptions::parse_options_raw(&value));
         }
     }
+    ctx.set_db_options(params.freeze());
 
     let user_info = ComputeUserInfo {
         endpoint,

proxy/src/serverless/websocket.rs

@@ -1,3 +1,4 @@
+use crate::proxy::ErrorSource;
 use crate::{
     cancellation::CancellationHandlerMain,
     config::ProxyConfig,
@@ -7,6 +8,7 @@ use crate::{
     proxy::{handle_client, ClientMode},
     rate_limiter::EndpointRateLimiter,
 };
+use anyhow::Context as _;
 use bytes::{Buf, BufMut, Bytes, BytesMut};
 use framed_websockets::{Frame, OpCode, WebSocketServer};
 use futures::{Sink, Stream};
@@ -165,7 +167,11 @@ pub async fn serve_websocket(
         Ok(Some(p)) => {
             ctx.set_success();
             ctx.log_connect();
-            p.proxy_pass().await
+            match p.proxy_pass().await {
+                Ok(()) => Ok(()),
+                Err(ErrorSource::Client(err)) => Err(err).context("client"),
+                Err(ErrorSource::Compute(err)) => Err(err).context("compute"),
+            }
         }
     }
 }

safekeeper/src/bin/safekeeper.rs

@@ -28,7 +28,8 @@ use utils::pid_file;
 
 use metrics::set_build_info_metric;
 use safekeeper::defaults::{
-    DEFAULT_HEARTBEAT_TIMEOUT, DEFAULT_HTTP_LISTEN_ADDR, DEFAULT_MAX_OFFLOADER_LAG_BYTES,
+    DEFAULT_CONTROL_FILE_SAVE_INTERVAL, DEFAULT_HEARTBEAT_TIMEOUT, DEFAULT_HTTP_LISTEN_ADDR,
+    DEFAULT_MAX_OFFLOADER_LAG_BYTES, DEFAULT_PARTIAL_BACKUP_CONCURRENCY,
     DEFAULT_PARTIAL_BACKUP_TIMEOUT, DEFAULT_PG_LISTEN_ADDR,
 };
 use safekeeper::http;
@@ -172,6 +173,7 @@ struct Args {
     walsenders_keep_horizon: bool,
     /// Enable partial backup. If disabled, safekeeper will not upload partial
     /// segments to remote storage.
+    /// TODO: now partial backup is always enabled, remove this flag.
     #[arg(long)]
     partial_backup_enabled: bool,
     /// Controls how long backup will wait until uploading the partial segment.
@@ -181,6 +183,18 @@ struct Args {
     /// be used in tests.
     #[arg(long)]
     disable_periodic_broker_push: bool,
+    /// Enable automatic switching to offloaded state.
+    #[arg(long)]
+    enable_offload: bool,
+    /// Delete local WAL files after offloading. When disabled, they will be left on disk.
+    #[arg(long)]
+    delete_offloaded_wal: bool,
+    /// Pending updates to control file will be automatically saved after this interval.
+    #[arg(long, value_parser = humantime::parse_duration, default_value = DEFAULT_CONTROL_FILE_SAVE_INTERVAL)]
+    control_file_save_interval: Duration,
+    /// Number of allowed concurrent uploads of partial segments to remote storage.
+    #[arg(long, default_value = DEFAULT_PARTIAL_BACKUP_CONCURRENCY)]
+    partial_backup_concurrency: usize,
 }
 
 // Like PathBufValueParser, but allows empty string.
@@ -328,9 +342,13 @@ async fn main() -> anyhow::Result<()> {
         sk_auth_token,
         current_thread_runtime: args.current_thread_runtime,
         walsenders_keep_horizon: args.walsenders_keep_horizon,
-        partial_backup_enabled: args.partial_backup_enabled,
+        partial_backup_enabled: true,
         partial_backup_timeout: args.partial_backup_timeout,
         disable_periodic_broker_push: args.disable_periodic_broker_push,
+        enable_offload: args.enable_offload,
+        delete_offloaded_wal: args.delete_offloaded_wal,
+        control_file_save_interval: args.control_file_save_interval,
+        partial_backup_concurrency: args.partial_backup_concurrency,
     };
 
     // initialize sentry if SENTRY_DSN is provided

safekeeper/src/control_file.rs

@@ -72,6 +72,9 @@ impl FileStorage {
         conf: &SafeKeeperConf,
         state: TimelinePersistentState,
     ) -> Result<FileStorage> {
+        // we don't support creating new timelines in offloaded state
+        assert!(matches!(state.eviction_state, EvictionState::Present));
+
         let store = FileStorage {
             timeline_dir,
             no_sync: conf.no_sync,
@@ -103,7 +106,7 @@ impl FileStorage {
     }
 
     /// Load control file from given directory.
-    pub fn load_control_file_from_dir(timeline_dir: &Utf8Path) -> Result<TimelinePersistentState> {
+    fn load_control_file_from_dir(timeline_dir: &Utf8Path) -> Result<TimelinePersistentState> {
         let path = timeline_dir.join(CONTROL_FILE_NAME);
         Self::load_control_file(path)
     }

safekeeper/src/copy_timeline.rs

@@ -15,7 +15,7 @@ use crate::{
     control_file::{FileStorage, Storage},
     pull_timeline::{create_temp_timeline_dir, load_temp_timeline, validate_temp_timeline},
     state::TimelinePersistentState,
-    timeline::{FullAccessTimeline, Timeline, TimelineError},
+    timeline::{Timeline, TimelineError, WalResidentTimeline},
     wal_backup::copy_s3_segments,
     wal_storage::{wal_file_paths, WalReader},
     GlobalTimelines,
@@ -46,7 +46,7 @@ pub async fn handle_request(request: Request) -> Result<()> {
         }
     }
 
-    let source_tli = request.source.full_access_guard().await?;
+    let source_tli = request.source.wal_residence_guard().await?;
 
     let conf = &GlobalTimelines::get_global_config();
     let ttid = request.destination_ttid;
@@ -159,7 +159,7 @@ pub async fn handle_request(request: Request) -> Result<()> {
 }
 
 async fn copy_disk_segments(
-    tli: &FullAccessTimeline,
+    tli: &WalResidentTimeline,
     wal_seg_size: usize,
     start_lsn: Lsn,
     end_lsn: Lsn,
@@ -183,7 +183,7 @@ async fn copy_disk_segments(
         let copy_end = copy_end - segment_start;
 
         let wal_file_path = {
-            let (normal, partial) = wal_file_paths(tli_dir_path, segment, wal_seg_size)?;
+            let (normal, partial) = wal_file_paths(tli_dir_path, segment, wal_seg_size);
 
             if segment == last_segment {
                 partial

safekeeper/src/debug_dump.rs

@@ -28,7 +28,8 @@ use crate::send_wal::WalSenderState;
 use crate::state::TimelineMemState;
 use crate::state::TimelinePersistentState;
 use crate::timeline::get_timeline_dir;
-use crate::timeline::FullAccessTimeline;
+use crate::timeline::WalResidentTimeline;
+use crate::timeline_manager;
 use crate::GlobalTimelines;
 use crate::SafeKeeperConf;
 
@@ -168,6 +169,7 @@ pub struct Memory {
     pub last_removed_segno: XLogSegNo,
     pub epoch_start_lsn: Lsn,
     pub mem_state: TimelineMemState,
+    pub mgr_status: timeline_manager::Status,
 
     // PhysicalStorage state.
     pub write_lsn: Lsn,
@@ -326,7 +328,7 @@ pub struct TimelineDigest {
 }
 
 pub async fn calculate_digest(
-    tli: &FullAccessTimeline,
+    tli: &WalResidentTimeline,
     request: TimelineDigestRequest,
 ) -> Result<TimelineDigest> {
     if request.from_lsn > request.until_lsn {

safekeeper/src/http/routes.rs

@@ -214,10 +214,10 @@ async fn timeline_snapshot_handler(request: Request<Body>) -> Result<Response<Bo
     let tli = GlobalTimelines::get(ttid).map_err(ApiError::from)?;
     // Note: with evicted timelines it should work better then de-evict them and
     // stream; probably start_snapshot would copy partial s3 file to dest path
-    // and stream control file, or return FullAccessTimeline if timeline is not
+    // and stream control file, or return WalResidentTimeline if timeline is not
     // evicted.
     let tli = tli
-        .full_access_guard()
+        .wal_residence_guard()
         .await
         .map_err(ApiError::InternalServerError)?;
 
@@ -283,7 +283,7 @@ async fn timeline_digest_handler(request: Request<Body>) -> Result<Response<Body
 
     let tli = GlobalTimelines::get(ttid).map_err(ApiError::from)?;
     let tli = tli
-        .full_access_guard()
+        .wal_residence_guard()
         .await
         .map_err(ApiError::InternalServerError)?;
 
@@ -306,7 +306,7 @@ async fn timeline_checkpoint_handler(request: Request<Body>) -> Result<Response<
     tli.write_shared_state()
         .await
         .sk
-        .state
+        .state_mut()
         .flush()
         .await
         .map_err(ApiError::InternalServerError)?;

safekeeper/src/json_ctrl.rs

@@ -21,7 +21,7 @@ use crate::safekeeper::{
 };
 use crate::safekeeper::{Term, TermHistory, TermLsn};
 use crate::state::TimelinePersistentState;
-use crate::timeline::FullAccessTimeline;
+use crate::timeline::WalResidentTimeline;
 use crate::GlobalTimelines;
 use postgres_backend::PostgresBackend;
 use postgres_ffi::encode_logical_message;
@@ -102,7 +102,7 @@ pub async fn handle_json_ctrl<IO: AsyncRead + AsyncWrite + Unpin>(
 async fn prepare_safekeeper(
     ttid: TenantTimelineId,
     pg_version: u32,
-) -> anyhow::Result<FullAccessTimeline> {
+) -> anyhow::Result<WalResidentTimeline> {
     let tli = GlobalTimelines::create(
         ttid,
         ServerInfo {
@@ -115,11 +115,11 @@ async fn prepare_safekeeper(
     )
     .await?;
 
-    tli.full_access_guard().await
+    tli.wal_residence_guard().await
 }
 
 async fn send_proposer_elected(
-    tli: &FullAccessTimeline,
+    tli: &WalResidentTimeline,
     term: Term,
     lsn: Lsn,
 ) -> anyhow::Result<()> {
@@ -151,7 +151,7 @@ pub struct InsertedWAL {
 /// Extend local WAL with new LogicalMessage record. To do that,
 /// create AppendRequest with new WAL and pass it to safekeeper.
 pub async fn append_logical_message(
-    tli: &FullAccessTimeline,
+    tli: &WalResidentTimeline,
     msg: &AppendLogicalMessage,
 ) -> anyhow::Result<InsertedWAL> {
     let wal_data = encode_logical_message(&msg.lm_prefix, &msg.lm_message);