refactor thread local accesses

## Problem

As reported in #10441 the `control_plane/README/md` incorrectly
specified that `--pg-version` should be specified in the `cargo neon
init` command. This is not the case and causes an invalid argument
error.

## Summary of changes

Fix the README

## Test Plan

I verified that the steps in the README now work locally. I connected to
the started postgres endpoint and executed some basic metadata queries.

.config/hakari.toml

@@ -30,6 +30,7 @@ workspace-members = [
     "vm_monitor",
     # All of these exist in libs and are not usually built independently.
     # Putting workspace hack there adds a bottleneck for cargo builds.
+    "alloc-metrics",
     "compute_api",
     "consumption_metrics",
     "desim",

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

@@ -181,6 +181,8 @@ runs:
           # Ref https://github.com/neondatabase/neon/issues/4540
           # cov_prefix=(scripts/coverage "--profraw-prefix=$GITHUB_JOB" --dir=/tmp/coverage run)
           cov_prefix=()
+          # Explicitly set LLVM_PROFILE_FILE to /dev/null to avoid writing *.profraw files
+          export LLVM_PROFILE_FILE=/dev/null
         else
           cov_prefix=()
         fi

.github/workflows/build_and_test.yml

@@ -87,22 +87,27 @@ jobs:
     uses: ./.github/workflows/build-build-tools-image.yml
     secrets: inherit
 
-  lint-openapi-spec:
-    runs-on: ubuntu-22.04
-    needs: [ meta, check-permissions ]
+  lint-yamls:
+    needs: [ meta, check-permissions, build-build-tools-image ]
     # We do need to run this in `.*-rc-pr` because of hotfixes.
     if: ${{ contains(fromJSON('["pr", "push-main", "storage-rc-pr", "proxy-rc-pr", "compute-rc-pr"]'), needs.meta.outputs.run-kind) }}
+    runs-on: [ self-hosted, small ]
+    container:
+      image: ${{ needs.build-build-tools-image.outputs.image }}
+      credentials:
+        username: ${{ github.actor }}
+        password: ${{ secrets.GITHUB_TOKEN }}
+      options: --init
+
     steps:
       - name: Harden the runner (Audit all outbound calls)
         uses: step-security/harden-runner@4d991eb9b905ef189e4c376166672c3f2f230481 # v2.11.0
         with:
           egress-policy: audit
+
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-      - uses: docker/login-action@74a5d142397b4f367a81961eba4e8cd7edddf772 # v3.4.0
-        with:
-          registry: ghcr.io
-          username: ${{ github.actor }}
-          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - run: make -C compute manifest-schema-validation
       - run: make lint-openapi-spec
 
   check-codestyle-python:
@@ -217,28 +222,6 @@ jobs:
       build-tools-image: ${{ needs.build-build-tools-image.outputs.image }}-bookworm
     secrets: inherit
 
-  validate-compute-manifest:
-    runs-on: ubuntu-22.04
-    needs: [ meta, check-permissions ]
-    # We do need to run this in `.*-rc-pr` because of hotfixes.
-    if: ${{ contains(fromJSON('["pr", "push-main", "storage-rc-pr", "proxy-rc-pr", "compute-rc-pr"]'), needs.meta.outputs.run-kind) }}
-    steps:
-      - name: Harden the runner (Audit all outbound calls)
-        uses: step-security/harden-runner@4d991eb9b905ef189e4c376166672c3f2f230481 # v2.11.0
-        with:
-          egress-policy: audit
-
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-
-      - name: Set up Node.js
-        uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4.4.0
-        with:
-          node-version: '24'
-
-      - name: Validate manifest against schema
-        run: |
-          make -C compute manifest-schema-validation
-
   build-and-test-locally:
     needs: [ meta, build-build-tools-image ]
     # We do need to run this in `.*-rc-pr` because of hotfixes.

.gitignore

@@ -29,3 +29,6 @@ docker-compose/docker-compose-parallel.yml
 
 # pgindent typedef lists
 *.list
+
+# Node
+**/node_modules/

Cargo.lock

@@ -61,6 +61,17 @@ dependencies = [
  "equator",
 ]
 
+[[package]]
+name = "alloc-metrics"
+version = "0.1.0"
+dependencies = [
+ "criterion",
+ "measured",
+ "metrics",
+ "thread_local",
+ "tikv-jemallocator",
+]
+
 [[package]]
 name = "allocator-api2"
 version = "0.2.16"
@@ -1872,6 +1883,7 @@ dependencies = [
  "diesel_derives",
  "itoa",
  "serde_json",
+ "uuid",
 ]
 
 [[package]]
@@ -2533,6 +2545,18 @@ dependencies = [
  "wasm-bindgen",
 ]
 
+[[package]]
+name = "getrandom"
+version = "0.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "26145e563e54f2cadc477553f1ec5ee650b00862f0a58bcd12cbdc5f0ea2d2f4"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "r-efi",
+ "wasi 0.14.2+wasi-0.2.4",
+]
+
 [[package]]
 name = "gettid"
 version = "0.1.3"
@@ -3606,9 +3630,9 @@ checksum = "4ee93343901ab17bd981295f2cf0026d4ad018c7c31ba84549a4ddbb47a45104"
 
 [[package]]
 name = "lock_api"
-version = "0.4.10"
+version = "0.4.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c1cc9717a20b1bb222f333e6a92fd32f7d8a18ddc5a3191a11af45dcbf4dcd16"
+checksum = "96936507f153605bddfcda068dd804796c84324ed2510809e5b2a624c81da765"
 dependencies = [
  "autocfg",
  "scopeguard",
@@ -3758,7 +3782,7 @@ dependencies = [
  "procfs",
  "prometheus",
  "rand 0.8.5",
- "rand_distr",
+ "rand_distr 0.4.3",
  "twox-hash",
 ]
 
@@ -3846,7 +3870,12 @@ checksum = "e5ce46fe64a9d73be07dcbe690a38ce1b293be448fd8ce1e6c1b8062c9f72c6a"
 name = "neon-shmem"
 version = "0.1.0"
 dependencies = [
+ "libc",
+ "lock_api",
  "nix 0.30.1",
+ "rand 0.9.1",
+ "rand_distr 0.5.1",
+ "rustc-hash 2.1.1",
  "tempfile",
  "thiserror 1.0.69",
  "workspace_hack",
@@ -5283,6 +5312,7 @@ name = "proxy"
 version = "0.1.0"
 dependencies = [
  "ahash",
+ "alloc-metrics",
  "anyhow",
  "arc-swap",
  "assert-json-diff",
@@ -5347,7 +5377,7 @@ dependencies = [
  "postgres_backend",
  "pq_proto",
  "rand 0.8.5",
- "rand_distr",
+ "rand_distr 0.4.3",
  "rcgen",
  "redis",
  "regex",
@@ -5358,7 +5388,7 @@ dependencies = [
  "reqwest-tracing",
  "rsa",
  "rstest",
- "rustc-hash 1.1.0",
+ "rustc-hash 2.1.1",
  "rustls 0.23.27",
  "rustls-native-certs 0.8.0",
  "rustls-pemfile 2.1.1",
@@ -5451,6 +5481,12 @@ dependencies = [
  "proc-macro2",
 ]
 
+[[package]]
+name = "r-efi"
+version = "5.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "69cdb34c158ceb288df11e18b4bd39de994f6657d83847bdffdbd7f346754b0f"
+
 [[package]]
 name = "rand"
 version = "0.7.3"
@@ -5475,6 +5511,16 @@ dependencies = [
  "rand_core 0.6.4",
 ]
 
+[[package]]
+name = "rand"
+version = "0.9.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9fbfd9d094a40bf3ae768db9361049ace4c0e04a4fd6b359518bd7b73a73dd97"
+dependencies = [
+ "rand_chacha 0.9.0",
+ "rand_core 0.9.3",
+]
+
 [[package]]
 name = "rand_chacha"
 version = "0.2.2"
@@ -5495,6 +5541,16 @@ dependencies = [
  "rand_core 0.6.4",
 ]
 
+[[package]]
+name = "rand_chacha"
+version = "0.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d3022b5f1df60f26e1ffddd6c66e8aa15de382ae63b3a0c1bfc0e4d3e3f325cb"
+dependencies = [
+ "ppv-lite86",
+ "rand_core 0.9.3",
+]
+
 [[package]]
 name = "rand_core"
 version = "0.5.1"
@@ -5513,6 +5569,15 @@ dependencies = [
  "getrandom 0.2.11",
 ]
 
+[[package]]
+name = "rand_core"
+version = "0.9.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "99d9a13982dcf210057a8a78572b2217b667c3beacbf3a0d8b454f6f82837d38"
+dependencies = [
+ "getrandom 0.3.3",
+]
+
 [[package]]
 name = "rand_distr"
 version = "0.4.3"
@@ -5523,6 +5588,16 @@ dependencies = [
  "rand 0.8.5",
 ]
 
+[[package]]
+name = "rand_distr"
+version = "0.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6a8615d50dcf34fa31f7ab52692afec947c4dd0ab803cc87cb3b0b4570ff7463"
+dependencies = [
+ "num-traits",
+ "rand 0.9.1",
+]
+
 [[package]]
 name = "rand_hc"
 version = "0.2.0"
@@ -6204,6 +6279,7 @@ dependencies = [
  "itertools 0.10.5",
  "jsonwebtoken",
  "metrics",
+ "nix 0.30.1",
  "once_cell",
  "pageserver_api",
  "parking_lot 0.12.1",
@@ -6211,6 +6287,7 @@ dependencies = [
  "postgres-protocol",
  "postgres_backend",
  "postgres_ffi",
+ "postgres_ffi_types",
  "postgres_versioninfo",
  "pprof",
  "pq_proto",
@@ -6255,7 +6332,7 @@ dependencies = [
  "anyhow",
  "const_format",
  "pageserver_api",
- "postgres_ffi",
+ "postgres_ffi_types",
  "postgres_versioninfo",
  "pq_proto",
  "serde",
@@ -6931,6 +7008,7 @@ dependencies = [
  "tokio-util",
  "tracing",
  "utils",
+ "uuid",
  "workspace_hack",
 ]
 
@@ -7266,12 +7344,10 @@ dependencies = [
 
 [[package]]
 name = "thread_local"
-version = "1.1.7"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3fdd6f064ccff2d6567adcb3873ca630700f00b5ad3f060c25b5dcfd9a4ce152"
+version = "1.1.9"
+source = "git+https://github.com/conradludgate/thread_local-rs?branch=no-tls-destructor-get#f9ca3d375745c14a632ae3ffe6a7a646dc8421a0"
 dependencies = [
  "cfg-if",
- "once_cell",
 ]
 
 [[package]]
@@ -8204,6 +8280,7 @@ dependencies = [
  "tracing-error",
  "tracing-subscriber",
  "tracing-utils",
+ "uuid",
  "walkdir",
 ]
 
@@ -8346,6 +8423,15 @@ version = "0.11.0+wasi-snapshot-preview1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9c8d87e72b64a3b4db28d11ce29237c246188f4f51057d65a7eab63b7987e423"
 
+[[package]]
+name = "wasi"
+version = "0.14.2+wasi-0.2.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9683f9a5a998d873c0d21fcbe3c083009670149a8fab228644b8bd36b2c48cb3"
+dependencies = [
+ "wit-bindgen-rt",
+]
+
 [[package]]
 name = "wasite"
 version = "0.1.0"
@@ -8703,6 +8789,15 @@ dependencies = [
  "windows-sys 0.48.0",
 ]
 
+[[package]]
+name = "wit-bindgen-rt"
+version = "0.39.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6f42320e61fe2cfd34354ecb597f86f413484a798ba44a8ca1165c58d42da6c1"
+dependencies = [
+ "bitflags 2.8.0",
+]
+
 [[package]]
 name = "workspace_hack"
 version = "0.1.0"
@@ -8805,7 +8900,6 @@ dependencies = [
  "tracing-log",
  "tracing-subscriber",
  "url",
- "uuid",
  "zeroize",
  "zstd",
  "zstd-safe",

Cargo.toml

@@ -130,6 +130,7 @@ jemalloc_pprof = { version = "0.7", features = ["symbolize", "flamegraph"] }
 jsonwebtoken = "9"
 lasso = "0.7"
 libc = "0.2"
+lock_api = "0.4.13"
 md5 = "0.7.0"
 measured = { version = "0.0.22", features=["lasso"] }
 measured-process = { version = "0.0.22" }
@@ -165,7 +166,7 @@ reqwest-middleware = "0.4"
 reqwest-retry = "0.7"
 routerify = "3"
 rpds = "0.13"
-rustc-hash = "1.1.0"
+rustc-hash = "2.1.1"
 rustls = { version = "0.23.16", default-features = false }
 rustls-pemfile = "2"
 rustls-pki-types = "1.11"
@@ -194,6 +195,7 @@ sync_wrapper = "0.1.2"
 tar = "0.4"
 test-context = "0.3"
 thiserror = "1.0"
+thread_local = "1.1.9"
 tikv-jemallocator = { version = "0.6", features = ["profiling", "stats", "unprefixed_malloc_on_supported_platforms"] }
 tikv-jemalloc-ctl = { version = "0.6", features = ["stats"] }
 tokio = { version = "1.43.1", features = ["macros"] }
@@ -252,6 +254,7 @@ azure_storage = { git = "https://github.com/neondatabase/azure-sdk-for-rust.git"
 azure_storage_blobs = { git = "https://github.com/neondatabase/azure-sdk-for-rust.git", branch = "neon", default-features = false, features = ["enable_reqwest_rustls"] }
 
 ## Local libraries
+alloc-metrics = { version = "0.1", path = "./libs/alloc-metrics/" }
 compute_api = { version = "0.1", path = "./libs/compute_api/" }
 consumption_metrics = { version = "0.1", path = "./libs/consumption_metrics/" }
 desim = { version = "0.1", path = "./libs/desim" }
@@ -301,6 +304,9 @@ tonic-build = "0.13.1"
 # Needed to get `tokio-postgres-rustls` to depend on our fork.
 tokio-postgres = { git = "https://github.com/neondatabase/rust-postgres.git", branch = "neon" }
 
+# Needed to fix a bug in alloc-metrics
+thread_local = { git = "https://github.com/conradludgate/thread_local-rs", branch = "no-tls-destructor-get" }
+
 ################# Binary contents sections
 
 [profile.release]

Makefile

@@ -2,7 +2,7 @@ ROOT_PROJECT_DIR := $(dir $(abspath $(lastword $(MAKEFILE_LIST))))
 
 # Where to install Postgres, default is ./pg_install, maybe useful for package
 # managers.
-POSTGRES_INSTALL_DIR ?= $(ROOT_PROJECT_DIR)/pg_install/
+POSTGRES_INSTALL_DIR ?= $(ROOT_PROJECT_DIR)/pg_install
 
 # Supported PostgreSQL versions
 POSTGRES_VERSIONS = v17 v16 v15 v14
@@ -14,7 +14,7 @@ POSTGRES_VERSIONS = v17 v16 v15 v14
 # it is derived from BUILD_TYPE.
 
 # All intermediate build artifacts are stored here.
-BUILD_DIR := build
+BUILD_DIR := $(ROOT_PROJECT_DIR)/build
 
 ICU_PREFIX_DIR := /usr/local/icu
 
@@ -212,7 +212,7 @@ neon-pgindent: postgres-v17-pg-bsd-indent neon-pg-ext-v17
 		FIND_TYPEDEF=$(ROOT_PROJECT_DIR)/vendor/postgres-v17/src/tools/find_typedef \
 		INDENT=$(BUILD_DIR)/v17/src/tools/pg_bsd_indent/pg_bsd_indent \
 		PGINDENT_SCRIPT=$(ROOT_PROJECT_DIR)/vendor/postgres-v17/src/tools/pgindent/pgindent \
-		-C $(BUILD_DIR)/neon-v17 \
+		-C $(BUILD_DIR)/pgxn-v17/neon \
 		-f $(ROOT_PROJECT_DIR)/pgxn/neon/Makefile pgindent
 
 
@@ -220,11 +220,15 @@ neon-pgindent: postgres-v17-pg-bsd-indent neon-pg-ext-v17
 setup-pre-commit-hook:
 	ln -s -f $(ROOT_PROJECT_DIR)/pre-commit.py .git/hooks/pre-commit
 
+build-tools/node_modules: build-tools/package.json
+	cd build-tools && $(if $(CI),npm ci,npm install)
+	touch build-tools/node_modules
+
 .PHONY: lint-openapi-spec
-lint-openapi-spec:
+lint-openapi-spec: build-tools/node_modules
 	# operation-2xx-response: pageserver timeline delete returns 404 on success
 	find . -iname "openapi_spec.y*ml" -exec\
-		docker run --rm -v ${PWD}:/spec ghcr.io/redocly/cli:1.34.4\
+		npx --prefix=build-tools/ redocly\
 			--skip-rule=operation-operationId --skip-rule=operation-summary --extends=minimal\
 			--skip-rule=no-server-example.com --skip-rule=operation-2xx-response\
 			lint {} \+

build-tools/Dockerfile

@@ -188,6 +188,12 @@ 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/*
 
+# Install node
+ENV NODE_VERSION=24
+RUN curl -fsSL https://deb.nodesource.com/setup_${NODE_VERSION}.x | bash - \
+    && apt install -y nodejs \
+    && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
+
 # Install docker
 RUN curl -fsSL https://download.docker.com/linux/ubuntu/gpg | gpg --dearmor -o /usr/share/keyrings/docker-archive-keyring.gpg \
     && echo "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/docker-archive-keyring.gpg] https://download.docker.com/linux/debian ${DEBIAN_VERSION} stable" > /etc/apt/sources.list.d/docker.list \
@@ -311,14 +317,14 @@ RUN curl -sSO https://static.rust-lang.org/rustup/dist/$(uname -m)-unknown-linux
     . "$HOME/.cargo/env" && \
     cargo --version && rustup --version && \
     rustup component add llvm-tools rustfmt clippy && \
-    cargo install rustfilt            --version ${RUSTFILT_VERSION} --locked && \
-    cargo install cargo-hakari        --version ${CARGO_HAKARI_VERSION} --locked && \
-    cargo install cargo-deny          --version ${CARGO_DENY_VERSION} --locked && \
-    cargo install cargo-hack          --version ${CARGO_HACK_VERSION} --locked && \
-    cargo install cargo-nextest       --version ${CARGO_NEXTEST_VERSION} --locked && \
-    cargo install cargo-chef          --version ${CARGO_CHEF_VERSION} --locked && \
-    cargo install diesel_cli          --version ${CARGO_DIESEL_CLI_VERSION} --locked \
-                                      --features postgres-bundled --no-default-features && \
+    cargo install rustfilt      --locked --version ${RUSTFILT_VERSION} && \
+    cargo install cargo-hakari  --locked --version ${CARGO_HAKARI_VERSION} && \
+    cargo install cargo-deny    --locked --version ${CARGO_DENY_VERSION} && \
+    cargo install cargo-hack    --locked --version ${CARGO_HACK_VERSION} && \
+    cargo install cargo-nextest --locked --version ${CARGO_NEXTEST_VERSION} && \
+    cargo install cargo-chef    --locked --version ${CARGO_CHEF_VERSION} && \
+    cargo install diesel_cli    --locked --version ${CARGO_DIESEL_CLI_VERSION} \
+                                --features postgres-bundled --no-default-features && \
     rm -rf /home/nonroot/.cargo/registry && \
     rm -rf /home/nonroot/.cargo/git
 

build-tools/package.json

@@ -0,0 +1,8 @@
+{
+  "name": "build-tools",
+  "private": true,
+  "devDependencies": {
+    "@redocly/cli": "1.34.4",
+    "@sourcemeta/jsonschema": "10.0.0"
+  }
+}

compute/Makefile

@@ -50,9 +50,9 @@ jsonnetfmt-format:
 	jsonnetfmt --in-place $(jsonnet_files)
 
 .PHONY: manifest-schema-validation
-manifest-schema-validation: node_modules
-	node_modules/.bin/jsonschema validate -d https://json-schema.org/draft/2020-12/schema manifest.schema.json manifest.yaml
+manifest-schema-validation: ../build-tools/node_modules
+	npx --prefix=../build-tools/ jsonschema validate -d https://json-schema.org/draft/2020-12/schema manifest.schema.json manifest.yaml
 
-node_modules: package.json
-	npm install
-	touch node_modules
+../build-tools/node_modules: ../build-tools/package.json
+	cd ../build-tools && $(if $(CI),npm ci,npm install)
+	touch ../build-tools/node_modules

compute/compute-node.Dockerfile

@@ -170,7 +170,29 @@ RUN case $DEBIAN_VERSION in \
 FROM build-deps AS pg-build
 ARG PG_VERSION
 COPY vendor/postgres-${PG_VERSION:?} postgres
+COPY compute/patches/postgres_fdw.patch .
+COPY compute/patches/pg_stat_statements_pg14-16.patch .
+COPY compute/patches/pg_stat_statements_pg17.patch .
 RUN cd postgres && \
+    # Apply patches to some contrib extensions
+    # For example, we need to grant EXECUTE on pg_stat_statements_reset() to {privileged_role_name}.
+    # In vanilla Postgres this function is limited to Postgres role superuser.
+    # In Neon we have {privileged_role_name} role that is not a superuser but replaces superuser in some cases.
+    # We could add the additional grant statements to the Postgres repository but it would be hard to maintain,
+    # whenever we need to pick up a new Postgres version and we want to limit the changes in our Postgres fork,
+    # so we do it here.
+    case "${PG_VERSION}" in \
+    "v14" | "v15" | "v16") \
+    patch -p1 < /pg_stat_statements_pg14-16.patch; \
+    ;; \
+    "v17") \
+    patch -p1 < /pg_stat_statements_pg17.patch; \
+    ;; \
+    *) \
+    # To do not forget to migrate patches to the next major version
+    echo "No contrib patches for this PostgreSQL version" && exit 1;; \
+    esac && \
+    patch -p1 < /postgres_fdw.patch && \
     export CONFIGURE_CMD="./configure CFLAGS='-O2 -g3 -fsigned-char' --enable-debug --with-openssl --with-uuid=ossp \
     --with-icu --with-libxml --with-libxslt --with-lz4" && \
     if [ "${PG_VERSION:?}" != "v14" ]; then \
@@ -184,8 +206,6 @@ RUN cd postgres && \
     echo 'trusted = true' >> /usr/local/pgsql/share/extension/autoinc.control && \
     echo 'trusted = true' >> /usr/local/pgsql/share/extension/dblink.control && \
     echo 'trusted = true' >> /usr/local/pgsql/share/extension/postgres_fdw.control && \
-    file=/usr/local/pgsql/share/extension/postgres_fdw--1.0.sql && [ -e $file ] && \
-    echo 'GRANT USAGE ON FOREIGN DATA WRAPPER postgres_fdw TO neon_superuser;' >> $file && \
     echo 'trusted = true' >> /usr/local/pgsql/share/extension/bloom.control && \
     echo 'trusted = true' >> /usr/local/pgsql/share/extension/earthdistance.control && \
     echo 'trusted = true' >> /usr/local/pgsql/share/extension/insert_username.control && \
@@ -195,34 +215,7 @@ RUN cd postgres && \
     echo 'trusted = true' >> /usr/local/pgsql/share/extension/pgrowlocks.control && \
     echo 'trusted = true' >> /usr/local/pgsql/share/extension/pgstattuple.control && \
     echo 'trusted = true' >> /usr/local/pgsql/share/extension/refint.control && \
-    echo 'trusted = true' >> /usr/local/pgsql/share/extension/xml2.control && \
-    # We need to grant EXECUTE on pg_stat_statements_reset() to neon_superuser.
-    # In vanilla postgres this function is limited to Postgres role superuser.
-    # In neon we have neon_superuser role that is not a superuser but replaces superuser in some cases.
-    # We could add the additional grant statements to the postgres repository but it would be hard to maintain,
-    # whenever we need to pick up a new postgres version and we want to limit the changes in our postgres fork,
-    # so we do it here.
-    for file in /usr/local/pgsql/share/extension/pg_stat_statements--*.sql; do \
-        filename=$(basename "$file"); \
-        # Note that there are no downgrade scripts for pg_stat_statements, so we \
-        # don't have to modify any downgrade paths or (much) older versions: we only \
-        # have to make sure every creation of the pg_stat_statements_reset function \
-        # also adds execute permissions to the neon_superuser.
-        case $filename in \
-          pg_stat_statements--1.4.sql) \
-            # pg_stat_statements_reset is first created with 1.4
-            echo 'GRANT EXECUTE ON FUNCTION pg_stat_statements_reset() TO neon_superuser;' >> $file; \
-            ;; \
-          pg_stat_statements--1.6--1.7.sql) \
-            # Then with the 1.6-1.7 migration it is re-created with a new signature, thus add the permissions back
-            echo 'GRANT EXECUTE ON FUNCTION pg_stat_statements_reset(Oid, Oid, bigint) TO neon_superuser;' >> $file; \
-            ;; \
-          pg_stat_statements--1.10--1.11.sql) \
-            # Then with the 1.10-1.11 migration it is re-created with a new signature again, thus add the permissions back
-            echo 'GRANT EXECUTE ON FUNCTION pg_stat_statements_reset(Oid, Oid, bigint, boolean) TO neon_superuser;' >> $file; \
-            ;; \
-        esac; \
-    done;
+    echo 'trusted = true' >> /usr/local/pgsql/share/extension/xml2.control
 
 # Set PATH for all the subsequent build steps
 ENV PATH="/usr/local/pgsql/bin:$PATH"
@@ -1524,7 +1517,7 @@ WORKDIR /ext-src
 COPY compute/patches/pg_duckdb_v031.patch .
 COPY compute/patches/duckdb_v120.patch .
 # pg_duckdb build requires source dir to be a git repo to get submodules
-# allow neon_superuser to execute some functions that in pg_duckdb are available to superuser only:
+# allow {privileged_role_name} to execute some functions that in pg_duckdb are available to superuser only:
 # - extension management function duckdb.install_extension()
 # - access to duckdb.extensions table and its sequence
 RUN git clone --depth 1 --branch v0.3.1 https://github.com/duckdb/pg_duckdb.git pg_duckdb-src && \

compute/package.json

@@ -1,7 +0,0 @@
-{
-  "name": "neon-compute",
-  "private": true,
-  "dependencies": {
-    "@sourcemeta/jsonschema": "9.3.4"
-  }
-} 

compute/patches/anon_v2.patch

@@ -1,22 +1,26 @@
 diff --git a/sql/anon.sql b/sql/anon.sql
-index 0cdc769..b450327 100644
+index 0cdc769..5eab1d6 100644
 --- a/sql/anon.sql
 +++ b/sql/anon.sql
-@@ -1141,3 +1141,15 @@ $$
+@@ -1141,3 +1141,19 @@ $$
  -- TODO : https://en.wikipedia.org/wiki/L-diversity
  
  -- TODO : https://en.wikipedia.org/wiki/T-closeness
 +
 +-- NEON Patches
 +
-+GRANT ALL ON SCHEMA anon to neon_superuser;
-+GRANT ALL ON ALL TABLES IN SCHEMA anon TO neon_superuser;
-+
 +DO $$
++DECLARE
++  privileged_role_name text;
 +BEGIN
-+    IF current_setting('server_version_num')::int >= 150000 THEN
-+        GRANT SET ON PARAMETER anon.transparent_dynamic_masking TO neon_superuser;
-+    END IF;
++  privileged_role_name := current_setting('neon.privileged_role_name');
++
++  EXECUTE format('GRANT ALL ON SCHEMA anon to %I', privileged_role_name);
++  EXECUTE format('GRANT ALL ON ALL TABLES IN SCHEMA anon TO %I', privileged_role_name);
++
++  IF current_setting('server_version_num')::int >= 150000 THEN
++    EXECUTE format('GRANT SET ON PARAMETER anon.transparent_dynamic_masking TO %I', privileged_role_name);
++  END IF;
 +END $$;
 diff --git a/sql/init.sql b/sql/init.sql
 index 7da6553..9b6164b 100644

compute/patches/pg_duckdb_v031.patch

@@ -21,13 +21,21 @@ index 3235cc8..6b892bc 100644
  include Makefile.global
  
 diff --git a/sql/pg_duckdb--0.2.0--0.3.0.sql b/sql/pg_duckdb--0.2.0--0.3.0.sql
-index d777d76..af60106 100644
+index d777d76..3b54396 100644
 --- a/sql/pg_duckdb--0.2.0--0.3.0.sql
 +++ b/sql/pg_duckdb--0.2.0--0.3.0.sql
-@@ -1056,3 +1056,6 @@ GRANT ALL ON FUNCTION duckdb.cache(TEXT, TEXT) TO PUBLIC;
+@@ -1056,3 +1056,14 @@ GRANT ALL ON FUNCTION duckdb.cache(TEXT, TEXT) TO PUBLIC;
  GRANT ALL ON FUNCTION duckdb.cache_info() TO PUBLIC;
  GRANT ALL ON FUNCTION duckdb.cache_delete(TEXT) TO PUBLIC;
  GRANT ALL ON PROCEDURE duckdb.recycle_ddb() TO PUBLIC;
-+GRANT ALL ON FUNCTION duckdb.install_extension(TEXT) TO neon_superuser;
-+GRANT ALL ON TABLE duckdb.extensions TO neon_superuser;
-+GRANT ALL ON SEQUENCE duckdb.extensions_table_seq TO neon_superuser;
++
++DO $$
++DECLARE
++  privileged_role_name text;
++BEGIN
++  privileged_role_name := current_setting('neon.privileged_role_name');
++
++  EXECUTE format('GRANT ALL ON FUNCTION duckdb.install_extension(TEXT) TO %I', privileged_role_name);
++  EXECUTE format('GRANT ALL ON TABLE duckdb.extensions TO %I', privileged_role_name);
++  EXECUTE format('GRANT ALL ON SEQUENCE duckdb.extensions_table_seq TO %I', privileged_role_name);
++END $$;

compute/patches/pg_stat_statements_pg14-16.patch

@@ -0,0 +1,34 @@
+diff --git a/contrib/pg_stat_statements/pg_stat_statements--1.4.sql b/contrib/pg_stat_statements/pg_stat_statements--1.4.sql
+index 58cdf600fce..8be57a996f6 100644
+--- a/contrib/pg_stat_statements/pg_stat_statements--1.4.sql
++++ b/contrib/pg_stat_statements/pg_stat_statements--1.4.sql
+@@ -46,3 +46,12 @@ GRANT SELECT ON pg_stat_statements TO PUBLIC;
+ 
+ -- Don't want this to be available to non-superusers.
+ REVOKE ALL ON FUNCTION pg_stat_statements_reset() FROM PUBLIC;
++
++DO $$
++DECLARE
++  privileged_role_name text;
++BEGIN
++  privileged_role_name := current_setting('neon.privileged_role_name');
++
++  EXECUTE format('GRANT EXECUTE ON FUNCTION pg_stat_statements_reset() TO %I', privileged_role_name);
++END $$;
+diff --git a/contrib/pg_stat_statements/pg_stat_statements--1.6--1.7.sql b/contrib/pg_stat_statements/pg_stat_statements--1.6--1.7.sql
+index 6fc3fed4c93..256345a8f79 100644
+--- a/contrib/pg_stat_statements/pg_stat_statements--1.6--1.7.sql
++++ b/contrib/pg_stat_statements/pg_stat_statements--1.6--1.7.sql
+@@ -20,3 +20,12 @@ LANGUAGE C STRICT PARALLEL SAFE;
+ 
+ -- Don't want this to be available to non-superusers.
+ REVOKE ALL ON FUNCTION pg_stat_statements_reset(Oid, Oid, bigint) FROM PUBLIC;
++
++DO $$
++DECLARE
++  privileged_role_name text;
++BEGIN
++  privileged_role_name := current_setting('neon.privileged_role_name');
++
++  EXECUTE format('GRANT EXECUTE ON FUNCTION pg_stat_statements_reset(Oid, Oid, bigint) TO %I', privileged_role_name);
++END $$;

compute/patches/pg_stat_statements_pg17.patch

@@ -0,0 +1,52 @@
+diff --git a/contrib/pg_stat_statements/pg_stat_statements--1.10--1.11.sql b/contrib/pg_stat_statements/pg_stat_statements--1.10--1.11.sql
+index 0bb2c397711..32764db1d8b 100644
+--- a/contrib/pg_stat_statements/pg_stat_statements--1.10--1.11.sql
++++ b/contrib/pg_stat_statements/pg_stat_statements--1.10--1.11.sql
+@@ -80,3 +80,12 @@ LANGUAGE C STRICT PARALLEL SAFE;
+ 
+ -- Don't want this to be available to non-superusers.
+ REVOKE ALL ON FUNCTION pg_stat_statements_reset(Oid, Oid, bigint, boolean) FROM PUBLIC;
++
++DO $$
++DECLARE
++  privileged_role_name text;
++BEGIN
++  privileged_role_name := current_setting('neon.privileged_role_name');
++
++  EXECUTE format('GRANT EXECUTE ON FUNCTION pg_stat_statements_reset(Oid, Oid, bigint, boolean) TO %I', privileged_role_name);
++END $$;
+\ No newline at end of file
+diff --git a/contrib/pg_stat_statements/pg_stat_statements--1.4.sql b/contrib/pg_stat_statements/pg_stat_statements--1.4.sql
+index 58cdf600fce..8be57a996f6 100644
+--- a/contrib/pg_stat_statements/pg_stat_statements--1.4.sql
++++ b/contrib/pg_stat_statements/pg_stat_statements--1.4.sql
+@@ -46,3 +46,12 @@ GRANT SELECT ON pg_stat_statements TO PUBLIC;
+ 
+ -- Don't want this to be available to non-superusers.
+ REVOKE ALL ON FUNCTION pg_stat_statements_reset() FROM PUBLIC;
++
++DO $$
++DECLARE
++  privileged_role_name text;
++BEGIN
++  privileged_role_name := current_setting('neon.privileged_role_name');
++
++  EXECUTE format('GRANT EXECUTE ON FUNCTION pg_stat_statements_reset() TO %I', privileged_role_name);
++END $$;
+diff --git a/contrib/pg_stat_statements/pg_stat_statements--1.6--1.7.sql b/contrib/pg_stat_statements/pg_stat_statements--1.6--1.7.sql
+index 6fc3fed4c93..256345a8f79 100644
+--- a/contrib/pg_stat_statements/pg_stat_statements--1.6--1.7.sql
++++ b/contrib/pg_stat_statements/pg_stat_statements--1.6--1.7.sql
+@@ -20,3 +20,12 @@ LANGUAGE C STRICT PARALLEL SAFE;
+ 
+ -- Don't want this to be available to non-superusers.
+ REVOKE ALL ON FUNCTION pg_stat_statements_reset(Oid, Oid, bigint) FROM PUBLIC;
++
++DO $$
++DECLARE
++  privileged_role_name text;
++BEGIN
++  privileged_role_name := current_setting('neon.privileged_role_name');
++
++  EXECUTE format('GRANT EXECUTE ON FUNCTION pg_stat_statements_reset(Oid, Oid, bigint) TO %I', privileged_role_name);
++END $$;

compute/patches/postgres_fdw.patch

@@ -0,0 +1,17 @@
+diff --git a/contrib/postgres_fdw/postgres_fdw--1.0.sql b/contrib/postgres_fdw/postgres_fdw--1.0.sql
+index a0f0fc1bf45..ee077f2eea6 100644
+--- a/contrib/postgres_fdw/postgres_fdw--1.0.sql
++++ b/contrib/postgres_fdw/postgres_fdw--1.0.sql
+@@ -16,3 +16,12 @@ LANGUAGE C STRICT;
+ CREATE FOREIGN DATA WRAPPER postgres_fdw
+   HANDLER postgres_fdw_handler
+   VALIDATOR postgres_fdw_validator;
++
++DO $$
++DECLARE
++  privileged_role_name text;
++BEGIN
++  privileged_role_name := current_setting('neon.privileged_role_name');
++
++  EXECUTE format('GRANT USAGE ON FOREIGN DATA WRAPPER postgres_fdw TO %I', privileged_role_name);
++END $$;

compute_tools/src/bin/compute_ctl.rs

@@ -87,6 +87,14 @@ struct Cli {
     #[arg(short = 'C', long, value_name = "DATABASE_URL")]
     pub connstr: String,
 
+    #[arg(
+        long,
+        default_value = "neon_superuser",
+        value_name = "PRIVILEGED_ROLE_NAME",
+        value_parser = Self::parse_privileged_role_name
+    )]
+    pub privileged_role_name: String,
+
     #[cfg(target_os = "linux")]
     #[arg(long, default_value = "neon-postgres")]
     pub cgroup: String,
@@ -149,6 +157,21 @@ impl Cli {
 
         Ok(url)
     }
+
+    /// For simplicity, we do not escape `privileged_role_name` anywhere in the code.
+    /// Since it's a system role, which we fully control, that's fine. Still, let's
+    /// validate it to avoid any surprises.
+    fn parse_privileged_role_name(value: &str) -> Result<String> {
+        use regex::Regex;
+
+        let pattern = Regex::new(r"^[a-z_]+$").unwrap();
+
+        if !pattern.is_match(value) {
+            bail!("--privileged-role-name can only contain lowercase letters and underscores")
+        }
+
+        Ok(value.to_string())
+    }
 }
 
 fn main() -> Result<()> {
@@ -178,6 +201,7 @@ fn main() -> Result<()> {
         ComputeNodeParams {
             compute_id: cli.compute_id,
             connstr,
+            privileged_role_name: cli.privileged_role_name.clone(),
             pgdata: cli.pgdata.clone(),
             pgbin: cli.pgbin.clone(),
             pgversion: get_pg_version_string(&cli.pgbin),
@@ -327,4 +351,49 @@ mod test {
         ])
         .expect_err("URL parameters are not allowed");
     }
+
+    #[test]
+    fn verify_privileged_role_name() {
+        // Valid name
+        let cli = Cli::parse_from([
+            "compute_ctl",
+            "--pgdata=test",
+            "--connstr=test",
+            "--compute-id=test",
+            "--privileged-role-name",
+            "my_superuser",
+        ]);
+        assert_eq!(cli.privileged_role_name, "my_superuser");
+
+        // Invalid names
+        Cli::try_parse_from([
+            "compute_ctl",
+            "--pgdata=test",
+            "--connstr=test",
+            "--compute-id=test",
+            "--privileged-role-name",
+            "NeonSuperuser",
+        ])
+        .expect_err("uppercase letters are not allowed");
+
+        Cli::try_parse_from([
+            "compute_ctl",
+            "--pgdata=test",
+            "--connstr=test",
+            "--compute-id=test",
+            "--privileged-role-name",
+            "$'neon_superuser",
+        ])
+        .expect_err("special characters are not allowed");
+
+        Cli::try_parse_from([
+            "compute_ctl",
+            "--pgdata=test",
+            "--connstr=test",
+            "--compute-id=test",
+            "--privileged-role-name",
+            "",
+        ])
+        .expect_err("empty name is not allowed");
+    }
 }

compute_tools/src/compute.rs

@@ -74,12 +74,20 @@ const DEFAULT_INSTALLED_EXTENSIONS_COLLECTION_INTERVAL: u64 = 3600;
 
 /// Static configuration params that don't change after startup. These mostly
 /// come from the CLI args, or are derived from them.
+#[derive(Clone, Debug)]
 pub struct ComputeNodeParams {
     /// The ID of the compute
     pub compute_id: String,
-    // Url type maintains proper escaping
+
+    /// Url type maintains proper escaping
     pub connstr: url::Url,
 
+    /// The name of the 'weak' superuser role, which we give to the users.
+    /// It follows the allow list approach, i.e., we take a standard role
+    /// and grant it extra permissions with explicit GRANTs here and there,
+    /// and core patches.
+    pub privileged_role_name: String,
+
     pub resize_swap_on_bind: bool,
     pub set_disk_quota_for_fs: Option<String>,
 
@@ -1286,9 +1294,7 @@ impl ComputeNode {
 
         // In case of error, log and fail the check, but don't crash.
         // We're playing it safe because these errors could be transient
-        // and we don't yet retry. Also being careful here allows us to
-        // be backwards compatible with safekeepers that don't have the
-        // TIMELINE_STATUS API yet.
+        // and we don't yet retry.
         if responses.len() < quorum {
             error!(
                 "failed sync safekeepers check {:?} {:?} {:?}",
@@ -1391,6 +1397,7 @@ impl ComputeNode {
         self.create_pgdata()?;
         config::write_postgres_conf(
             pgdata_path,
+            &self.params,
             &pspec.spec,
             self.params.internal_http_port,
             tls_config,
@@ -1739,6 +1746,7 @@ impl ComputeNode {
         }
 
         // Run migrations separately to not hold up cold starts
+        let params = self.params.clone();
         tokio::spawn(async move {
             let mut conf = conf.as_ref().clone();
             conf.application_name("compute_ctl:migrations");
@@ -1750,7 +1758,7 @@ impl ComputeNode {
                             eprintln!("connection error: {e}");
                         }
                     });
-                    if let Err(e) = handle_migrations(&mut client).await {
+                    if let Err(e) = handle_migrations(params, &mut client).await {
                         error!("Failed to run migrations: {}", e);
                     }
                 }
@@ -1829,6 +1837,7 @@ impl ComputeNode {
         let pgdata_path = Path::new(&self.params.pgdata);
         config::write_postgres_conf(
             pgdata_path,
+            &self.params,
             &spec,
             self.params.internal_http_port,
             tls_config,
@@ -2441,14 +2450,31 @@ LIMIT 100",
     pub fn spawn_lfc_offload_task(self: &Arc<Self>, interval: Duration) {
         self.terminate_lfc_offload_task();
         let secs = interval.as_secs();
-        info!("spawning lfc offload worker with {secs}s interval");
         let this = self.clone();
+
+        info!("spawning LFC offload worker with {secs}s interval");
         let handle = spawn(async move {
             let mut interval = time::interval(interval);
             interval.tick().await; // returns immediately
             loop {
                 interval.tick().await;
-                this.offload_lfc_async().await;
+
+                let prewarm_state = this.state.lock().unwrap().lfc_prewarm_state.clone();
+                // Do not offload LFC state if we are currently prewarming or any issue occurred.
+                // If we'd do that, we might override the LFC state in endpoint storage with some
+                // incomplete state. Imagine a situation:
+                // 1. Endpoint started with `autoprewarm: true`
+                // 2. While prewarming is not completed, we upload the new incomplete state
+                // 3. Compute gets interrupted and restarts
+                // 4. We start again and try to prewarm with the state from 2. instead of the previous complete state
+                if matches!(
+                    prewarm_state,
+                    LfcPrewarmState::Completed
+                        | LfcPrewarmState::NotPrewarmed
+                        | LfcPrewarmState::Skipped
+                ) {
+                    this.offload_lfc_async().await;
+                }
             }
         });
         *self.lfc_offload_task.lock().unwrap() = Some(handle);

compute_tools/src/compute_prewarm.rs

@@ -89,7 +89,7 @@ impl ComputeNode {
         self.state.lock().unwrap().lfc_offload_state.clone()
     }
 
-    /// If there is a prewarm request ongoing, return false, true otherwise
+    /// If there is a prewarm request ongoing, return `false`, `true` otherwise.
     pub fn prewarm_lfc(self: &Arc<Self>, from_endpoint: Option<String>) -> bool {
         {
             let state = &mut self.state.lock().unwrap().lfc_prewarm_state;
@@ -101,15 +101,25 @@ impl ComputeNode {
 
         let cloned = self.clone();
         spawn(async move {
-            let Err(err) = cloned.prewarm_impl(from_endpoint).await else {
-                cloned.state.lock().unwrap().lfc_prewarm_state = LfcPrewarmState::Completed;
-                return;
-            };
-            crate::metrics::LFC_PREWARM_ERRORS.inc();
-            error!(%err, "prewarming lfc");
-            cloned.state.lock().unwrap().lfc_prewarm_state = LfcPrewarmState::Failed {
-                error: err.to_string(),
+            let state = match cloned.prewarm_impl(from_endpoint).await {
+                Ok(true) => LfcPrewarmState::Completed,
+                Ok(false) => {
+                    info!(
+                        "skipping LFC prewarm because LFC state is not found in endpoint storage"
+                    );
+                    LfcPrewarmState::Skipped
+                }
+                Err(err) => {
+                    crate::metrics::LFC_PREWARM_ERRORS.inc();
+                    error!(%err, "could not prewarm LFC");
+
+                    LfcPrewarmState::Failed {
+                        error: err.to_string(),
+                    }
+                }
             };
+
+            cloned.state.lock().unwrap().lfc_prewarm_state = state;
         });
         true
     }
@@ -120,15 +130,21 @@ impl ComputeNode {
         EndpointStoragePair::from_spec_and_endpoint(state.pspec.as_ref().unwrap(), from_endpoint)
     }
 
-    async fn prewarm_impl(&self, from_endpoint: Option<String>) -> Result<()> {
+    /// Request LFC state from endpoint storage and load corresponding pages into Postgres.
+    /// Returns a result with `false` if the LFC state is not found in endpoint storage.
+    async fn prewarm_impl(&self, from_endpoint: Option<String>) -> Result<bool> {
         let EndpointStoragePair { url, token } = self.endpoint_storage_pair(from_endpoint)?;
-        info!(%url, "requesting LFC state from endpoint storage");
 
+        info!(%url, "requesting LFC state from endpoint storage");
         let request = Client::new().get(&url).bearer_auth(token);
         let res = request.send().await.context("querying endpoint storage")?;
         let status = res.status();
-        if status != StatusCode::OK {
-            bail!("{status} querying endpoint storage")
+        match status {
+            StatusCode::OK => (),
+            StatusCode::NOT_FOUND => {
+                return Ok(false);
+            }
+            _ => bail!("{status} querying endpoint storage"),
         }
 
         let mut uncompressed = Vec::new();
@@ -141,7 +157,8 @@ impl ComputeNode {
             .await
             .context("decoding LFC state")?;
         let uncompressed_len = uncompressed.len();
-        info!(%url, "downloaded LFC state, uncompressed size {uncompressed_len}, loading into postgres");
+
+        info!(%url, "downloaded LFC state, uncompressed size {uncompressed_len}, loading into Postgres");
 
         ComputeNode::get_maintenance_client(&self.tokio_conn_conf)
             .await
@@ -149,7 +166,9 @@ impl ComputeNode {
             .query_one("select neon.prewarm_local_cache($1)", &[&uncompressed])
             .await
             .context("loading LFC state into postgres")
-            .map(|_| ())
+            .map(|_| ())?;
+
+        Ok(true)
     }
 
     /// If offload request is ongoing, return false, true otherwise
@@ -177,12 +196,14 @@ impl ComputeNode {
 
     async fn offload_lfc_with_state_update(&self) {
         crate::metrics::LFC_OFFLOADS.inc();
+
         let Err(err) = self.offload_lfc_impl().await else {
             self.state.lock().unwrap().lfc_offload_state = LfcOffloadState::Completed;
             return;
         };
+
         crate::metrics::LFC_OFFLOAD_ERRORS.inc();
-        error!(%err, "offloading lfc");
+        error!(%err, "could not offload LFC state to endpoint storage");
         self.state.lock().unwrap().lfc_offload_state = LfcOffloadState::Failed {
             error: err.to_string(),
         };
@@ -190,7 +211,7 @@ impl ComputeNode {
 
     async fn offload_lfc_impl(&self) -> Result<()> {
         let EndpointStoragePair { url, token } = self.endpoint_storage_pair(None)?;
-        info!(%url, "requesting LFC state from postgres");
+        info!(%url, "requesting LFC state from Postgres");
 
         let mut compressed = Vec::new();
         ComputeNode::get_maintenance_client(&self.tokio_conn_conf)
@@ -205,13 +226,17 @@ impl ComputeNode {
             .read_to_end(&mut compressed)
             .await
             .context("compressing LFC state")?;
+
         let compressed_len = compressed.len();
         info!(%url, "downloaded LFC state, compressed size {compressed_len}, writing to endpoint storage");
 
         let request = Client::new().put(url).bearer_auth(token).body(compressed);
         match request.send().await {
             Ok(res) if res.status() == StatusCode::OK => Ok(()),
-            Ok(res) => bail!("Error writing to endpoint storage: {}", res.status()),
+            Ok(res) => bail!(
+                "Request to endpoint storage failed with status: {}",
+                res.status()
+            ),
             Err(err) => Err(err).context("writing to endpoint storage"),
         }
     }

compute_tools/src/config.rs

@@ -9,6 +9,7 @@ use std::path::Path;
 use compute_api::responses::TlsConfig;
 use compute_api::spec::{ComputeAudit, ComputeMode, ComputeSpec, GenericOption};
 
+use crate::compute::ComputeNodeParams;
 use crate::pg_helpers::{
     GenericOptionExt, GenericOptionsSearch, PgOptionsSerialize, escape_conf_value,
 };
@@ -41,6 +42,7 @@ pub fn line_in_file(path: &Path, line: &str) -> Result<bool> {
 /// Create or completely rewrite configuration file specified by `path`
 pub fn write_postgres_conf(
     pgdata_path: &Path,
+    params: &ComputeNodeParams,
     spec: &ComputeSpec,
     extension_server_port: u16,
     tls_config: &Option<TlsConfig>,
@@ -54,14 +56,15 @@ pub fn write_postgres_conf(
         writeln!(file, "{conf}")?;
     }
 
+    // Stripe size GUC should be defined prior to connection string
+    if let Some(stripe_size) = spec.shard_stripe_size {
+        writeln!(file, "neon.stripe_size={stripe_size}")?;
+    }
     // Add options for connecting to storage
     writeln!(file, "# Neon storage settings")?;
     if let Some(s) = &spec.pageserver_connstring {
         writeln!(file, "neon.pageserver_connstring={}", escape_conf_value(s))?;
     }
-    if let Some(stripe_size) = spec.shard_stripe_size {
-        writeln!(file, "neon.stripe_size={stripe_size}")?;
-    }
     if !spec.safekeeper_connstrings.is_empty() {
         let mut neon_safekeepers_value = String::new();
         tracing::info!(
@@ -161,6 +164,12 @@ pub fn write_postgres_conf(
         }
     }
 
+    writeln!(
+        file,
+        "neon.privileged_role_name={}",
+        escape_conf_value(params.privileged_role_name.as_str())
+    )?;
+
     // If there are any extra options in the 'settings' field, append those
     if spec.cluster.settings.is_some() {
         writeln!(file, "# Managed by compute_ctl: begin")?;

compute_tools/src/http/openapi_spec.yaml

@@ -613,11 +613,11 @@ components:
         - skipped
       properties:
         status:
-          description: Lfc prewarm status
-          enum: [not_prewarmed, prewarming, completed, failed]
+          description: LFC prewarm status
+          enum: [not_prewarmed, prewarming, completed, failed, skipped]
           type: string
         error:
-          description: Lfc prewarm error, if any
+          description: LFC prewarm error, if any
           type: string
         total:
           description: Total pages processed
@@ -635,11 +635,11 @@ components:
         - status
       properties:
         status:
-          description: Lfc offload status
+          description: LFC offload status
           enum: [not_offloaded, offloading, completed, failed]
           type: string
         error:
-          description: Lfc offload error, if any
+          description: LFC offload error, if any
           type: string
 
     PromoteState:

compute_tools/src/migrations/0001-add_bypass_rls_to_privileged_role.sql

@@ -0,0 +1 @@
+ALTER ROLE {privileged_role_name} BYPASSRLS;

compute_tools/src/migrations/0001-neon_superuser_bypass_rls.sql

@@ -1 +0,0 @@
-ALTER ROLE neon_superuser BYPASSRLS;

compute_tools/src/migrations/0002-alter_roles.sql

@@ -15,7 +15,7 @@ DO $$
 DECLARE
     role_name text;
 BEGIN
-    FOR role_name IN SELECT rolname FROM pg_roles WHERE pg_has_role(rolname, 'neon_superuser', 'member')
+    FOR role_name IN SELECT rolname FROM pg_roles WHERE pg_has_role(rolname, '{privileged_role_name}', 'member')
     LOOP
         RAISE NOTICE 'EXECUTING ALTER ROLE % INHERIT', quote_ident(role_name);
         EXECUTE 'ALTER ROLE ' || quote_ident(role_name) || ' INHERIT';
@@ -23,7 +23,7 @@ BEGIN
 
     FOR role_name IN SELECT rolname FROM pg_roles
         WHERE
-            NOT pg_has_role(rolname, 'neon_superuser', 'member') AND NOT starts_with(rolname, 'pg_')
+            NOT pg_has_role(rolname, '{privileged_role_name}', 'member') AND NOT starts_with(rolname, 'pg_')
     LOOP
         RAISE NOTICE 'EXECUTING ALTER ROLE % NOBYPASSRLS', quote_ident(role_name);
         EXECUTE 'ALTER ROLE ' || quote_ident(role_name) || ' NOBYPASSRLS';

compute_tools/src/migrations/0003-grant_pg_create_subscription_to_privileged_role.sql

@@ -1,6 +1,6 @@
 DO $$
 BEGIN
     IF (SELECT setting::numeric >= 160000 FROM pg_settings WHERE name = 'server_version_num') THEN
-        EXECUTE 'GRANT pg_create_subscription TO neon_superuser';
+        EXECUTE 'GRANT pg_create_subscription TO {privileged_role_name}';
     END IF;
 END $$;

compute_tools/src/migrations/0004-grant_pg_monitor_to_neon_superuser.sql

@@ -1 +0,0 @@
-GRANT pg_monitor TO neon_superuser WITH ADMIN OPTION;

compute_tools/src/migrations/0004-grant_pg_monitor_to_privileged_role.sql

@@ -0,0 +1 @@
+GRANT pg_monitor TO {privileged_role_name} WITH ADMIN OPTION;

compute_tools/src/migrations/0005-grant_all_on_tables_to_privileged_role.sql

@@ -1,4 +1,4 @@
 -- SKIP: Deemed insufficient for allowing relations created by extensions to be
---       interacted with by neon_superuser without permission issues.
+--       interacted with by {privileged_role_name} without permission issues.
 
-ALTER DEFAULT PRIVILEGES IN SCHEMA public GRANT ALL ON TABLES TO neon_superuser;
+ALTER DEFAULT PRIVILEGES IN SCHEMA public GRANT ALL ON TABLES TO {privileged_role_name};

compute_tools/src/migrations/0006-grant_all_on_sequences_to_privileged_role.sql

@@ -1,4 +1,4 @@
 -- SKIP: Deemed insufficient for allowing relations created by extensions to be
---       interacted with by neon_superuser without permission issues.
+--       interacted with by {privileged_role_name} without permission issues.
 
-ALTER DEFAULT PRIVILEGES IN SCHEMA public GRANT ALL ON SEQUENCES TO neon_superuser;
+ALTER DEFAULT PRIVILEGES IN SCHEMA public GRANT ALL ON SEQUENCES TO {privileged_role_name};

compute_tools/src/migrations/0007-grant_all_on_tables_with_grant_option_to_privileged_role.sql

@@ -1,3 +1,3 @@
 -- SKIP: Moved inline to the handle_grants() functions.
 
-ALTER DEFAULT PRIVILEGES IN SCHEMA public GRANT ALL ON TABLES TO neon_superuser WITH GRANT OPTION;
+ALTER DEFAULT PRIVILEGES IN SCHEMA public GRANT ALL ON TABLES TO {privileged_role_name} WITH GRANT OPTION;

compute_tools/src/migrations/0008-grant_all_on_sequences_with_grant_option_to_privileged_role.sql

@@ -1,3 +1,3 @@
 -- SKIP: Moved inline to the handle_grants() functions.
 
-ALTER DEFAULT PRIVILEGES IN SCHEMA public GRANT ALL ON SEQUENCES TO neon_superuser WITH GRANT OPTION;
+ALTER DEFAULT PRIVILEGES IN SCHEMA public GRANT ALL ON SEQUENCES TO {privileged_role_name} WITH GRANT OPTION;

compute_tools/src/migrations/0010-grant_snapshot_synchronization_funcs_to_privileged_role.sql

@@ -1,7 +1,7 @@
 DO $$
 BEGIN
     IF (SELECT setting::numeric >= 160000 FROM pg_settings WHERE name = 'server_version_num') THEN
-       EXECUTE 'GRANT EXECUTE ON FUNCTION pg_export_snapshot TO neon_superuser';
-       EXECUTE 'GRANT EXECUTE ON FUNCTION pg_log_standby_snapshot TO neon_superuser';
+       EXECUTE 'GRANT EXECUTE ON FUNCTION pg_export_snapshot TO {privileged_role_name}';
+       EXECUTE 'GRANT EXECUTE ON FUNCTION pg_log_standby_snapshot TO {privileged_role_name}';
     END IF;
 END $$;

compute_tools/src/migrations/0011-grant_pg_show_replication_origin_status_to_neon_superuser.sql

@@ -1 +0,0 @@
-GRANT EXECUTE ON FUNCTION pg_show_replication_origin_status TO neon_superuser;

compute_tools/src/migrations/0011-grant_pg_show_replication_origin_status_to_privileged_role.sql

@@ -0,0 +1 @@
+GRANT EXECUTE ON FUNCTION pg_show_replication_origin_status TO {privileged_role_name};

compute_tools/src/migrations/0012-grant_pg_signal_backend_to_neon_superuser.sql

@@ -1 +0,0 @@
-GRANT pg_signal_backend TO neon_superuser WITH ADMIN OPTION;

compute_tools/src/migrations/0012-grant_pg_signal_backend_to_privileged_role.sql

@@ -0,0 +1 @@
+GRANT pg_signal_backend TO {privileged_role_name} WITH ADMIN OPTION;

compute_tools/src/spec.rs

@@ -9,6 +9,7 @@ use reqwest::StatusCode;
 use tokio_postgres::Client;
 use tracing::{error, info, instrument};
 
+use crate::compute::ComputeNodeParams;
 use crate::config;
 use crate::metrics::{CPLANE_REQUESTS_TOTAL, CPlaneRequestRPC, UNKNOWN_HTTP_STATUS};
 use crate::migration::MigrationRunner;
@@ -169,7 +170,7 @@ pub async fn handle_neon_extension_upgrade(client: &mut Client) -> Result<()> {
 }
 
 #[instrument(skip_all)]
-pub async fn handle_migrations(client: &mut Client) -> Result<()> {
+pub async fn handle_migrations(params: ComputeNodeParams, client: &mut Client) -> Result<()> {
     info!("handle migrations");
 
     // !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@@ -178,26 +179,59 @@ pub async fn handle_migrations(client: &mut Client) -> Result<()> {
 
     // Add new migrations in numerical order.
     let migrations = [
-        include_str!("./migrations/0001-neon_superuser_bypass_rls.sql"),
-        include_str!("./migrations/0002-alter_roles.sql"),
-        include_str!("./migrations/0003-grant_pg_create_subscription_to_neon_superuser.sql"),
-        include_str!("./migrations/0004-grant_pg_monitor_to_neon_superuser.sql"),
-        include_str!("./migrations/0005-grant_all_on_tables_to_neon_superuser.sql"),
-        include_str!("./migrations/0006-grant_all_on_sequences_to_neon_superuser.sql"),
-        include_str!(
-            "./migrations/0007-grant_all_on_tables_to_neon_superuser_with_grant_option.sql"
+        &format!(
+            include_str!("./migrations/0001-add_bypass_rls_to_privileged_role.sql"),
+            privileged_role_name = params.privileged_role_name
         ),
-        include_str!(
-            "./migrations/0008-grant_all_on_sequences_to_neon_superuser_with_grant_option.sql"
+        &format!(
+            include_str!("./migrations/0002-alter_roles.sql"),
+            privileged_role_name = params.privileged_role_name
+        ),
+        &format!(
+            include_str!("./migrations/0003-grant_pg_create_subscription_to_privileged_role.sql"),
+            privileged_role_name = params.privileged_role_name
+        ),
+        &format!(
+            include_str!("./migrations/0004-grant_pg_monitor_to_privileged_role.sql"),
+            privileged_role_name = params.privileged_role_name
+        ),
+        &format!(
+            include_str!("./migrations/0005-grant_all_on_tables_to_privileged_role.sql"),
+            privileged_role_name = params.privileged_role_name
+        ),
+        &format!(
+            include_str!("./migrations/0006-grant_all_on_sequences_to_privileged_role.sql"),
+            privileged_role_name = params.privileged_role_name
+        ),
+        &format!(
+            include_str!(
+                "./migrations/0007-grant_all_on_tables_with_grant_option_to_privileged_role.sql"
+            ),
+            privileged_role_name = params.privileged_role_name
+        ),
+        &format!(
+            include_str!(
+                "./migrations/0008-grant_all_on_sequences_with_grant_option_to_privileged_role.sql"
+            ),
+            privileged_role_name = params.privileged_role_name
         ),
         include_str!("./migrations/0009-revoke_replication_for_previously_allowed_roles.sql"),
-        include_str!(
-            "./migrations/0010-grant_snapshot_synchronization_funcs_to_neon_superuser.sql"
+        &format!(
+            include_str!(
+                "./migrations/0010-grant_snapshot_synchronization_funcs_to_privileged_role.sql"
+            ),
+            privileged_role_name = params.privileged_role_name
         ),
-        include_str!(
-            "./migrations/0011-grant_pg_show_replication_origin_status_to_neon_superuser.sql"
+        &format!(
+            include_str!(
+                "./migrations/0011-grant_pg_show_replication_origin_status_to_privileged_role.sql"
+            ),
+            privileged_role_name = params.privileged_role_name
+        ),
+        &format!(
+            include_str!("./migrations/0012-grant_pg_signal_backend_to_privileged_role.sql"),
+            privileged_role_name = params.privileged_role_name
         ),
-        include_str!("./migrations/0012-grant_pg_signal_backend_to_neon_superuser.sql"),
     ];
 
     MigrationRunner::new(client, &migrations)

compute_tools/src/spec_apply.rs

@@ -13,14 +13,14 @@ use tokio_postgres::Client;
 use tokio_postgres::error::SqlState;
 use tracing::{Instrument, debug, error, info, info_span, instrument, warn};
 
-use crate::compute::{ComputeNode, ComputeState};
+use crate::compute::{ComputeNode, ComputeNodeParams, ComputeState};
 use crate::pg_helpers::{
     DatabaseExt, Escaping, GenericOptionsSearch, RoleExt, get_existing_dbs_async,
     get_existing_roles_async,
 };
 use crate::spec_apply::ApplySpecPhase::{
-    CreateAndAlterDatabases, CreateAndAlterRoles, CreateAvailabilityCheck, CreateNeonSuperuser,
-    CreatePgauditExtension, CreatePgauditlogtofileExtension, CreateSchemaNeon,
+    CreateAndAlterDatabases, CreateAndAlterRoles, CreateAvailabilityCheck, CreatePgauditExtension,
+    CreatePgauditlogtofileExtension, CreatePrivilegedRole, CreateSchemaNeon,
     DisablePostgresDBPgAudit, DropInvalidDatabases, DropRoles, FinalizeDropLogicalSubscriptions,
     HandleNeonExtension, HandleOtherExtensions, RenameAndDeleteDatabases, RenameRoles,
     RunInEachDatabase,
@@ -49,6 +49,7 @@ impl ComputeNode {
             // Proceed with post-startup configuration. Note, that order of operations is important.
             let client = Self::get_maintenance_client(&conf).await?;
             let spec = spec.clone();
+            let params = Arc::new(self.params.clone());
 
             let databases = get_existing_dbs_async(&client).await?;
             let roles = get_existing_roles_async(&client)
@@ -157,6 +158,7 @@ impl ComputeNode {
 
                     let conf = Arc::new(conf);
                     let fut = Self::apply_spec_sql_db(
+                        params.clone(),
                         spec.clone(),
                         conf,
                         ctx.clone(),
@@ -185,7 +187,7 @@ impl ComputeNode {
             }
 
             for phase in [
-                CreateNeonSuperuser,
+                CreatePrivilegedRole,
                 DropInvalidDatabases,
                 RenameRoles,
                 CreateAndAlterRoles,
@@ -195,6 +197,7 @@ impl ComputeNode {
             ] {
                 info!("Applying phase {:?}", &phase);
                 apply_operations(
+                    params.clone(),
                     spec.clone(),
                     ctx.clone(),
                     jwks_roles.clone(),
@@ -243,6 +246,7 @@ impl ComputeNode {
                     }
 
                     let fut = Self::apply_spec_sql_db(
+                        params.clone(),
                         spec.clone(),
                         conf,
                         ctx.clone(),
@@ -293,6 +297,7 @@ impl ComputeNode {
             for phase in phases {
                 debug!("Applying phase {:?}", &phase);
                 apply_operations(
+                    params.clone(),
                     spec.clone(),
                     ctx.clone(),
                     jwks_roles.clone(),
@@ -313,7 +318,9 @@ impl ComputeNode {
     /// May opt to not connect to databases that don't have any scheduled
     /// operations.  The function is concurrency-controlled with the provided
     /// semaphore.  The caller has to make sure the semaphore isn't exhausted.
+    #[allow(clippy::too_many_arguments)] // TODO: needs bigger refactoring
     async fn apply_spec_sql_db(
+        params: Arc<ComputeNodeParams>,
         spec: Arc<ComputeSpec>,
         conf: Arc<tokio_postgres::Config>,
         ctx: Arc<tokio::sync::RwLock<MutableApplyContext>>,
@@ -328,6 +335,7 @@ impl ComputeNode {
 
         for subphase in subphases {
             apply_operations(
+                params.clone(),
                 spec.clone(),
                 ctx.clone(),
                 jwks_roles.clone(),
@@ -467,7 +475,7 @@ pub enum PerDatabasePhase {
 
 #[derive(Clone, Debug)]
 pub enum ApplySpecPhase {
-    CreateNeonSuperuser,
+    CreatePrivilegedRole,
     DropInvalidDatabases,
     RenameRoles,
     CreateAndAlterRoles,
@@ -510,6 +518,7 @@ pub struct MutableApplyContext {
 /// - No timeouts have (yet) been implemented.
 /// - The caller is responsible for limiting and/or applying concurrency.
 pub async fn apply_operations<'a, Fut, F>(
+    params: Arc<ComputeNodeParams>,
     spec: Arc<ComputeSpec>,
     ctx: Arc<RwLock<MutableApplyContext>>,
     jwks_roles: Arc<HashSet<String>>,
@@ -527,7 +536,7 @@ where
         debug!("Processing phase {:?}", &apply_spec_phase);
         let ctx = ctx;
 
-        let mut ops = get_operations(&spec, &ctx, &jwks_roles, &apply_spec_phase)
+        let mut ops = get_operations(&params, &spec, &ctx, &jwks_roles, &apply_spec_phase)
             .await?
             .peekable();
 
@@ -588,14 +597,18 @@ where
 /// sort/merge/batch execution, but for now this is a nice way to improve
 /// batching behavior of the commands.
 async fn get_operations<'a>(
+    params: &'a ComputeNodeParams,
     spec: &'a ComputeSpec,
     ctx: &'a RwLock<MutableApplyContext>,
     jwks_roles: &'a HashSet<String>,
     apply_spec_phase: &'a ApplySpecPhase,
 ) -> Result<Box<dyn Iterator<Item = Operation> + 'a + Send>> {
     match apply_spec_phase {
-        ApplySpecPhase::CreateNeonSuperuser => Ok(Box::new(once(Operation {
-            query: include_str!("sql/create_neon_superuser.sql").to_string(),
+        ApplySpecPhase::CreatePrivilegedRole => Ok(Box::new(once(Operation {
+            query: format!(
+                include_str!("sql/create_privileged_role.sql"),
+                privileged_role_name = params.privileged_role_name
+            ),
             comment: None,
         }))),
         ApplySpecPhase::DropInvalidDatabases => {
@@ -697,8 +710,9 @@ async fn get_operations<'a>(
                         None => {
                             let query = if !jwks_roles.contains(role.name.as_str()) {
                                 format!(
-                                    "CREATE ROLE {} INHERIT CREATEROLE CREATEDB BYPASSRLS REPLICATION IN ROLE neon_superuser {}",
+                                    "CREATE ROLE {} INHERIT CREATEROLE CREATEDB BYPASSRLS REPLICATION IN ROLE {} {}",
                                     role.name.pg_quote(),
+                                    params.privileged_role_name,
                                     role.to_pg_options(),
                                 )
                             } else {
@@ -849,8 +863,9 @@ async fn get_operations<'a>(
                                 // ALL PRIVILEGES grants CREATE, CONNECT, and TEMPORARY on the database
                                 // (see https://www.postgresql.org/docs/current/ddl-priv.html)
                                 query: format!(
-                                    "GRANT ALL PRIVILEGES ON DATABASE {} TO neon_superuser",
-                                    db.name.pg_quote()
+                                    "GRANT ALL PRIVILEGES ON DATABASE {} TO {}",
+                                    db.name.pg_quote(),
+                                    params.privileged_role_name
                                 ),
                                 comment: None,
                             },

compute_tools/src/sql/create_neon_superuser.sql

@@ -1,8 +0,0 @@
-DO $$
-    BEGIN
-        IF NOT EXISTS (SELECT FROM pg_catalog.pg_roles WHERE rolname = 'neon_superuser')
-        THEN
-            CREATE ROLE neon_superuser CREATEDB CREATEROLE NOLOGIN REPLICATION BYPASSRLS IN ROLE pg_read_all_data, pg_write_all_data;
-        END IF;
-    END
-$$;

compute_tools/src/sql/create_privileged_role.sql

@@ -0,0 +1,8 @@
+DO $$
+    BEGIN
+        IF NOT EXISTS (SELECT FROM pg_catalog.pg_roles WHERE rolname = '{privileged_role_name}')
+        THEN
+            CREATE ROLE {privileged_role_name} CREATEDB CREATEROLE NOLOGIN REPLICATION BYPASSRLS IN ROLE pg_read_all_data, pg_write_all_data;
+        END IF;
+    END
+$$;

control_plane/README.md

@@ -8,10 +8,10 @@ code changes locally, but not suitable for running production systems.
 
 ## Example: Start with Postgres 16
 
-To create and start a local development environment with Postgres 16, you will need to provide `--pg-version` flag to 3 of the start-up commands.
+To create and start a local development environment with Postgres 16, you will need to provide `--pg-version` flag to 2 of the start-up commands.
 
 ```shell
-cargo neon init --pg-version 16
+cargo neon init
 cargo neon start
 cargo neon tenant create --set-default --pg-version 16
 cargo neon endpoint create main --pg-version 16

control_plane/src/bin/neon_local.rs

@@ -631,6 +631,10 @@ struct EndpointCreateCmdArgs {
         help = "Allow multiple primary endpoints running on the same branch. Shouldn't be used normally, but useful for tests."
     )]
     allow_multiple: bool,
+
+    /// Only allow changing it on creation
+    #[clap(long, help = "Name of the privileged role for the endpoint")]
+    privileged_role_name: Option<String>,
 }
 
 #[derive(clap::Args)]
@@ -1480,6 +1484,7 @@ async fn handle_endpoint(subcmd: &EndpointCmd, env: &local_env::LocalEnv) -> Res
                 args.grpc,
                 !args.update_catalog,
                 false,
+                args.privileged_role_name.clone(),
             )?;
         }
         EndpointCmd::Start(args) => {

control_plane/src/endpoint.rs

@@ -99,6 +99,7 @@ pub struct EndpointConf {
     features: Vec<ComputeFeature>,
     cluster: Option<Cluster>,
     compute_ctl_config: ComputeCtlConfig,
+    privileged_role_name: Option<String>,
 }
 
 //
@@ -199,6 +200,7 @@ impl ComputeControlPlane {
         grpc: bool,
         skip_pg_catalog_updates: bool,
         drop_subscriptions_before_start: bool,
+        privileged_role_name: Option<String>,
     ) -> Result<Arc<Endpoint>> {
         let pg_port = pg_port.unwrap_or_else(|| self.get_port());
         let external_http_port = external_http_port.unwrap_or_else(|| self.get_port() + 1);
@@ -236,6 +238,7 @@ impl ComputeControlPlane {
             features: vec![],
             cluster: None,
             compute_ctl_config: compute_ctl_config.clone(),
+            privileged_role_name: privileged_role_name.clone(),
         });
 
         ep.create_endpoint_dir()?;
@@ -257,6 +260,7 @@ impl ComputeControlPlane {
                 features: vec![],
                 cluster: None,
                 compute_ctl_config,
+                privileged_role_name,
             })?,
         )?;
         std::fs::write(
@@ -332,6 +336,9 @@ pub struct Endpoint {
 
     /// The compute_ctl config for the endpoint's compute.
     compute_ctl_config: ComputeCtlConfig,
+
+    /// The name of the privileged role for the endpoint.
+    privileged_role_name: Option<String>,
 }
 
 #[derive(PartialEq, Eq)]
@@ -432,6 +439,7 @@ impl Endpoint {
             features: conf.features,
             cluster: conf.cluster,
             compute_ctl_config: conf.compute_ctl_config,
+            privileged_role_name: conf.privileged_role_name,
         })
     }
 
@@ -464,7 +472,7 @@ impl Endpoint {
         conf.append("max_connections", "100");
         conf.append("wal_level", "logical");
         // wal_sender_timeout is the maximum time to wait for WAL replication.
-        // It also defines how often the walreciever will send a feedback message to the wal sender.
+        // It also defines how often the walreceiver will send a feedback message to the wal sender.
         conf.append("wal_sender_timeout", "5s");
         conf.append("listen_addresses", &self.pg_address.ip().to_string());
         conf.append("port", &self.pg_address.port().to_string());
@@ -870,6 +878,10 @@ impl Endpoint {
             cmd.arg("--dev");
         }
 
+        if let Some(privileged_role_name) = self.privileged_role_name.clone() {
+            cmd.args(["--privileged-role-name", &privileged_role_name]);
+        }
+
         let child = cmd.spawn()?;
         // set up a scopeguard to kill & wait for the child in case we panic or bail below
         let child = scopeguard::guard(child, |mut child| {

control_plane/storcon_cli/src/main.rs

@@ -76,6 +76,12 @@ enum Command {
     NodeStartDelete {
         #[arg(long)]
         node_id: NodeId,
+        /// When `force` is true, skip waiting for shards to prewarm during migration.
+        /// This can significantly speed up node deletion since prewarming all shards
+        /// can take considerable time, but may result in slower initial access to
+        /// migrated shards until they warm up naturally.
+        #[arg(long)]
+        force: bool,
     },
     /// Cancel deletion of the specified pageserver and wait for `timeout`
     /// for the operation to be canceled. May be retried.
@@ -952,13 +958,14 @@ async fn main() -> anyhow::Result<()> {
                 .dispatch::<(), ()>(Method::DELETE, format!("control/v1/node/{node_id}"), None)
                 .await?;
         }
-        Command::NodeStartDelete { node_id } => {
+        Command::NodeStartDelete { node_id, force } => {
+            let query = if force {
+                format!("control/v1/node/{node_id}/delete?force=true")
+            } else {
+                format!("control/v1/node/{node_id}/delete")
+            };
             storcon_client
-                .dispatch::<(), ()>(
-                    Method::PUT,
-                    format!("control/v1/node/{node_id}/delete"),
-                    None,
-                )
+                .dispatch::<(), ()>(Method::PUT, query, None)
                 .await?;
             println!("Delete started for {node_id}");
         }

docs/pageserver-services.md

@@ -75,7 +75,7 @@ CLI examples:
 * AWS S3  : `env AWS_ACCESS_KEY_ID='SOMEKEYAAAAASADSAH*#' AWS_SECRET_ACCESS_KEY='SOMEsEcReTsd292v' ${PAGESERVER_BIN} -c "remote_storage={bucket_name='some-sample-bucket',bucket_region='eu-north-1', prefix_in_bucket='/test_prefix/'}"`
 
 For Amazon AWS S3, a key id and secret access key could be located in `~/.aws/credentials` if awscli was ever configured to work with the desired bucket, on the AWS Settings page for a certain user. Also note, that the bucket names does not contain any protocols when used on AWS.
-For local S3 installations, refer to the their documentation for name format and credentials.
+For local S3 installations, refer to their documentation for name format and credentials.
 
 Similar to other pageserver settings, toml config file can be used to configure either of the storages as backup targets.
 Required sections are:

libs/alloc-metrics/Cargo.toml

@@ -0,0 +1,18 @@
+[package]
+name = "alloc-metrics"
+version = "0.1.0"
+edition.workspace = true
+license.workspace = true
+
+[dependencies]
+metrics.workspace = true
+measured.workspace = true
+thread_local.workspace = true
+
+[dev-dependencies]
+criterion.workspace = true
+tikv-jemallocator.workspace = true
+
+[[bench]]
+harness = false
+name = "alloc"

libs/alloc-metrics/benches/alloc.rs

@@ -0,0 +1,110 @@
+use std::alloc::{GlobalAlloc, Layout, System, handle_alloc_error};
+
+use alloc_metrics::TrackedAllocator;
+use criterion::{
+    AxisScale, BenchmarkGroup, BenchmarkId, Criterion, PlotConfiguration, measurement::Measurement,
+};
+use measured::FixedCardinalityLabel;
+use tikv_jemallocator::Jemalloc;
+
+fn main() {
+    let mut c = Criterion::default().configure_from_args();
+    bench(&mut c);
+    c.final_summary();
+}
+
+#[rustfmt::skip]
+fn bench(c: &mut Criterion) {
+    bench_alloc(c.benchmark_group("alloc/system"),  &System, &ALLOC_SYSTEM);
+    bench_alloc(c.benchmark_group("alloc/jemalloc"), &Jemalloc, &ALLOC_JEMALLOC);
+
+    bench_dealloc(c.benchmark_group("dealloc/system"), &System, &ALLOC_SYSTEM);
+    bench_dealloc(c.benchmark_group("dealloc/jemalloc"), &Jemalloc, &ALLOC_JEMALLOC);
+}
+
+#[derive(FixedCardinalityLabel, Clone, Copy, Debug)]
+#[label(singleton = "memory_context")]
+pub enum MemoryContext {
+    Root,
+    Test,
+}
+
+static ALLOC_SYSTEM: TrackedAllocator<System, MemoryContext> =
+    unsafe { TrackedAllocator::new(System, MemoryContext::Root) };
+static ALLOC_JEMALLOC: TrackedAllocator<Jemalloc, MemoryContext> =
+    unsafe { TrackedAllocator::new(Jemalloc, MemoryContext::Root) };
+
+const KB: u64 = 1024;
+const SIZES: [u64; 6] = [64, 256, KB, 4 * KB, 16 * KB, KB * KB];
+
+fn bench_alloc<A: GlobalAlloc>(
+    mut g: BenchmarkGroup<'_, impl Measurement>,
+    alloc1: &'static A,
+    alloc2: &'static TrackedAllocator<A, MemoryContext>,
+) {
+    g.plot_config(PlotConfiguration::default().summary_scale(AxisScale::Logarithmic));
+    for size in SIZES {
+        let layout = Layout::from_size_align(size as usize, 8).unwrap();
+
+        g.throughput(criterion::Throughput::Bytes(size));
+        g.bench_with_input(BenchmarkId::new("default", size), &layout, |b, &layout| {
+            let bs = criterion::BatchSize::NumBatches(10 + size.ilog2() as u64);
+            b.iter_batched(|| {}, |()| Alloc::new(alloc1, layout), bs);
+        });
+        g.bench_with_input(BenchmarkId::new("tracked", size), &layout, |b, &layout| {
+            let _scope = alloc2.scope(MemoryContext::Test);
+
+            let bs = criterion::BatchSize::NumBatches(10 + size.ilog2() as u64);
+            b.iter_batched(|| {}, |()| Alloc::new(alloc2, layout), bs);
+        });
+    }
+}
+
+fn bench_dealloc<A: GlobalAlloc>(
+    mut g: BenchmarkGroup<'_, impl Measurement>,
+    alloc1: &'static A,
+    alloc2: &'static TrackedAllocator<A, MemoryContext>,
+) {
+    g.plot_config(PlotConfiguration::default().summary_scale(AxisScale::Logarithmic));
+    for size in SIZES {
+        let layout = Layout::from_size_align(size as usize, 8).unwrap();
+
+        g.throughput(criterion::Throughput::Bytes(size));
+        g.bench_with_input(BenchmarkId::new("default", size), &layout, |b, &layout| {
+            let bs = criterion::BatchSize::NumBatches(10 + size.ilog2() as u64);
+            b.iter_batched(|| Alloc::new(alloc1, layout), drop, bs);
+        });
+        g.bench_with_input(BenchmarkId::new("tracked", size), &layout, |b, &layout| {
+            let _scope = alloc2.scope(MemoryContext::Test);
+
+            let bs = criterion::BatchSize::NumBatches(10 + size.ilog2() as u64);
+            b.iter_batched(|| Alloc::new(alloc2, layout), drop, bs);
+        });
+    }
+}
+
+struct Alloc<'a, A: GlobalAlloc> {
+    alloc: &'a A,
+    ptr: *mut u8,
+    layout: Layout,
+}
+
+impl<'a, A: GlobalAlloc> Alloc<'a, A> {
+    fn new(alloc: &'a A, layout: Layout) -> Self {
+        let ptr = unsafe { alloc.alloc(layout) };
+        if ptr.is_null() {
+            handle_alloc_error(layout);
+        }
+
+        // actually make the page resident.
+        unsafe { ptr.cast::<u8>().write(1) };
+
+        Self { alloc, ptr, layout }
+    }
+}
+
+impl<'a, A: GlobalAlloc> Drop for Alloc<'a, A> {
+    fn drop(&mut self) {
+        unsafe { self.alloc.dealloc(self.ptr, self.layout) };
+    }
+}

libs/alloc-metrics/src/counters.rs

@@ -0,0 +1,48 @@
+use std::marker::PhantomData;
+
+use measured::{
+    FixedCardinalityLabel, LabelGroup, label::StaticLabelSet, metric::MetricFamilyEncoding,
+};
+use metrics::{CounterPairAssoc, Dec, Inc, MeasuredCounterPairState};
+
+use crate::metric_vec::DenseMetricVec;
+
+pub struct DenseCounterPairVec<
+    A: CounterPairAssoc<LabelGroupSet = StaticLabelSet<L>>,
+    L: FixedCardinalityLabel + LabelGroup,
+> {
+    pub vec: DenseMetricVec<MeasuredCounterPairState, L>,
+    pub _marker: PhantomData<A>,
+}
+
+impl<A: CounterPairAssoc<LabelGroupSet = StaticLabelSet<L>>, L: FixedCardinalityLabel + LabelGroup>
+    DenseCounterPairVec<A, L>
+{
+    pub fn new() -> Self {
+        Self {
+            vec: DenseMetricVec::new(),
+            _marker: PhantomData,
+        }
+    }
+}
+
+impl<T, A, L> ::measured::metric::group::MetricGroup<T> for DenseCounterPairVec<A, L>
+where
+    T: ::measured::metric::group::Encoding,
+    ::measured::metric::counter::CounterState: ::measured::metric::MetricEncoding<T>,
+    A: CounterPairAssoc<LabelGroupSet = StaticLabelSet<L>>,
+    L: FixedCardinalityLabel + LabelGroup,
+{
+    fn collect_group_into(&self, enc: &mut T) -> Result<(), T::Err> {
+        // write decrement first to avoid a race condition where inc - dec < 0
+        T::write_help(enc, A::DEC_NAME, A::DEC_HELP)?;
+        self.vec
+            .collect_family_into(A::DEC_NAME, &mut Dec(&mut *enc))?;
+
+        T::write_help(enc, A::INC_NAME, A::INC_HELP)?;
+        self.vec
+            .collect_family_into(A::INC_NAME, &mut Inc(&mut *enc))?;
+
+        Ok(())
+    }
+}

libs/alloc-metrics/src/lib.rs

@@ -0,0 +1,441 @@
+//! Tagged allocator measurements.
+
+mod counters;
+mod metric_vec;
+
+use std::{
+    alloc::{GlobalAlloc, Layout},
+    cell::Cell,
+    marker::PhantomData,
+    sync::{
+        OnceLock,
+        atomic::{AtomicU64, Ordering::Relaxed},
+    },
+};
+
+use measured::{
+    FixedCardinalityLabel, LabelGroup, MetricGroup,
+    label::StaticLabelSet,
+    metric::{MetricEncoding, counter::CounterState, group::Encoding, name::MetricName},
+};
+use metrics::{CounterPairAssoc, MeasuredCounterPairState};
+use thread_local::ThreadLocal;
+
+type AllocCounter<T> = counters::DenseCounterPairVec<AllocPair<T>, T>;
+
+pub struct TrackedAllocator<A, T: 'static + Send + Sync + FixedCardinalityLabel + LabelGroup> {
+    inner: A,
+
+    /// potentially high-content fallback if the thread was not registered.
+    default_counters: MeasuredCounterPairState,
+    /// Default tag to use if this thread is not registered.
+    default_tag: T,
+
+    thread: OnceLock<RegisteredThread<T>>,
+
+    /// where thread alloc data is eventually saved to, even if threads are shutdown.
+    global: OnceLock<AllocCounter<T>>,
+}
+
+impl<A, T> TrackedAllocator<A, T>
+where
+    T: 'static + Send + Sync + FixedCardinalityLabel + LabelGroup,
+{
+    /// # Safety
+    ///
+    /// [`FixedCardinalityLabel`] must be implemented correctly, fully dense, and must not panic.
+    pub const unsafe fn new(alloc: A, default: T) -> Self {
+        TrackedAllocator {
+            inner: alloc,
+            default_tag: default,
+            default_counters: MeasuredCounterPairState {
+                inc: CounterState {
+                    count: AtomicU64::new(0),
+                },
+                dec: CounterState {
+                    count: AtomicU64::new(0),
+                },
+            },
+            thread: OnceLock::new(),
+            global: OnceLock::new(),
+        }
+    }
+
+    /// Allocations
+    pub fn register_thread(&'static self) {
+        self.register_thread_inner();
+    }
+
+    pub fn scope(&'static self, tag: T) -> AllocScope<'static, T> {
+        let cell = self.register_thread_inner();
+        let last = cell.replace(tag);
+        AllocScope { cell, last }
+    }
+
+    fn register_thread_inner(&'static self) -> &'static Cell<T> {
+        let thread = self.thread.get_or_init(|| RegisteredThread {
+            scope: ThreadLocal::new(),
+            state: ThreadLocal::new(),
+        });
+
+        thread.state.get_or(|| ThreadState {
+            counters: AllocCounter::new(),
+            global: self.global.get_or_init(AllocCounter::new),
+        });
+
+        thread.scope.get_or(|| Cell::new(self.default_tag))
+    }
+}
+
+macro_rules! alloc {
+    ($alloc_fn:ident) => {
+        unsafe fn $alloc_fn(&self, layout: Layout) -> *mut u8 {
+            let Ok((tagged_layout, tag_offset)) = layout.extend(Layout::new::<T>()) else {
+                return std::ptr::null_mut();
+            };
+            let tagged_layout = tagged_layout.pad_to_align();
+
+            // Safety: The layout is not zero-sized.
+            let ptr = unsafe { self.inner.$alloc_fn(tagged_layout) };
+
+            // allocation failed.
+            if ptr.is_null() {
+                return ptr;
+            }
+
+            // We are being very careful here to not allocate or panic.
+            let thread = self.thread.get().map(|s| (s.scope.get(), s.state.get()));
+            let tag = thread.and_then(|t| t.0).map_or(self.default_tag, Cell::get);
+
+            // Allocation successful. Write our tag
+            // Safety: tag_offset is inbounds of the ptr
+            unsafe { ptr.add(tag_offset).cast::<T>().write(tag) }
+
+            let counters = thread.and_then(|t| t.1).map(|s| &s.counters);
+            let metric = if let Some(counters) = counters {
+                counters.vec.get_metric(tag)
+            } else {
+                // if tag is not default, then the thread state would have been registered, therefore tag must be default.
+                &self.default_counters
+            };
+
+            metric.inc.count.fetch_add(layout.size() as u64, Relaxed);
+
+            ptr
+        }
+    };
+}
+
+// We will tag our allocation by adding `T` to the end of the layout.
+// This is ok only as long as it does not overflow. If it does, we will
+// just fail the allocation by returning null.
+//
+// Safety: we will not unwind during alloc, and we will ensure layouts are handled correctly.
+unsafe impl<A, T> GlobalAlloc for TrackedAllocator<A, T>
+where
+    A: GlobalAlloc,
+    T: 'static + Send + Sync + FixedCardinalityLabel + LabelGroup,
+{
+    alloc!(alloc);
+    alloc!(alloc_zeroed);
+
+    unsafe fn realloc(&self, ptr: *mut u8, layout: Layout, new_size: usize) -> *mut u8 {
+        // SAFETY: the caller must ensure that the `new_size` does not overflow.
+        // `layout.align()` comes from a `Layout` and is thus guaranteed to be valid.
+        let new_layout = unsafe { Layout::from_size_align_unchecked(new_size, layout.align()) };
+
+        let Ok((new_tagged_layout, new_tag_offset)) = new_layout.extend(Layout::new::<T>()) else {
+            return std::ptr::null_mut();
+        };
+        let new_tagged_layout = new_tagged_layout.pad_to_align();
+
+        let Ok((tagged_layout, tag_offset)) = layout.extend(Layout::new::<T>()) else {
+            // Safety: This layout clearly did not match what was originally allocated,
+            // otherwise alloc() would have caught this error and returned null.
+            unsafe { std::hint::unreachable_unchecked() }
+        };
+        let tagged_layout = tagged_layout.pad_to_align();
+
+        // get the tag set during alloc
+        // Safety: tag_offset is inbounds of the ptr
+        let tag = unsafe { ptr.add(tag_offset).cast::<T>().read() };
+
+        // Safety: layout sizes are correct
+        let new_ptr = unsafe {
+            self.inner
+                .realloc(ptr, tagged_layout, new_tagged_layout.size())
+        };
+
+        // allocation failed.
+        if new_ptr.is_null() {
+            return new_ptr;
+        }
+
+        // We are being very careful here to not allocate or panic.
+        let thread = self.thread.get().map(|s| (s.scope.get(), s.state.get()));
+        let new_tag = thread.and_then(|t| t.0).map_or(self.default_tag, Cell::get);
+
+        // Allocation successful. Write our tag
+        // Safety: new_tag_offset is inbounds of the ptr
+        unsafe { new_ptr.add(new_tag_offset).cast::<T>().write(new_tag) }
+
+        let counters = thread.and_then(|t| t.1).map(|s| &s.counters);
+        let counters = counters.or_else(|| self.global.get());
+        let (new_metric, old_metric) = if let Some(counters) = counters {
+            let new_metric = counters.vec.get_metric(new_tag);
+            let old_metric = counters.vec.get_metric(tag);
+
+            (new_metric, old_metric)
+        } else {
+            // no tag was registered at all, therefore both tags must be default.
+            (&self.default_counters, &self.default_counters)
+        };
+
+        let (inc, dec) = if tag.encode() != new_tag.encode() {
+            (new_layout.size() as u64, layout.size() as u64)
+        } else if new_layout.size() > layout.size() {
+            ((new_layout.size() - layout.size()) as u64, 0)
+        } else {
+            (0, (layout.size() - new_layout.size()) as u64)
+        };
+
+        new_metric.inc.count.fetch_add(inc, Relaxed);
+        old_metric.dec.count.fetch_add(dec, Relaxed);
+
+        new_ptr
+    }
+
+    unsafe fn dealloc(&self, ptr: *mut u8, layout: Layout) {
+        let Ok((tagged_layout, tag_offset)) = layout.extend(Layout::new::<T>()) else {
+            // Safety: This layout clearly did not match what was originally allocated,
+            // otherwise alloc() would have caught this error and returned null.
+            unsafe { std::hint::unreachable_unchecked() }
+        };
+        let tagged_layout = tagged_layout.pad_to_align();
+
+        // get the tag set during alloc
+        // Safety: tag_offset is inbounds of the ptr
+        let tag = unsafe { ptr.add(tag_offset).cast::<T>().read() };
+
+        // Safety: caller upholds contract for us
+        unsafe { self.inner.dealloc(ptr, tagged_layout) }
+
+        // We are being very careful here to not allocate or panic.
+        let thread = self.thread.get().map(|s| (s.scope.get(), s.state.get()));
+        let counters = thread.and_then(|t| t.1).map(|s| &s.counters);
+        let counters = counters.or_else(|| self.global.get());
+
+        let metric = if let Some(counters) = counters {
+            counters.vec.get_metric(tag)
+        } else {
+            // if tag is not default, then global would have been registered, therefore tag must be default.
+            &self.default_counters
+        };
+
+        metric.dec.count.fetch_add(layout.size() as u64, Relaxed);
+    }
+}
+
+pub struct AllocScope<'a, T: FixedCardinalityLabel> {
+    cell: &'a Cell<T>,
+    last: T,
+}
+
+impl<'a, T: FixedCardinalityLabel> Drop for AllocScope<'a, T> {
+    fn drop(&mut self) {
+        self.cell.set(self.last);
+    }
+}
+
+struct AllocPair<T>(PhantomData<T>);
+
+impl<T: FixedCardinalityLabel + LabelGroup> CounterPairAssoc for AllocPair<T> {
+    const INC_NAME: &'static MetricName = MetricName::from_str("allocated_bytes");
+    const DEC_NAME: &'static MetricName = MetricName::from_str("deallocated_bytes");
+
+    const INC_HELP: &'static str = "total number of bytes allocated";
+    const DEC_HELP: &'static str = "total number of bytes deallocated";
+
+    type LabelGroupSet = StaticLabelSet<T>;
+}
+
+struct RegisteredThread<T: 'static + Send + Sync + FixedCardinalityLabel + LabelGroup> {
+    /// Current memory context for this thread.
+    scope: ThreadLocal<Cell<T>>,
+    /// per thread state containing low contention counters for faster allocations.
+    state: ThreadLocal<ThreadState<T>>,
+}
+
+struct ThreadState<T: 'static + FixedCardinalityLabel + LabelGroup> {
+    counters: AllocCounter<T>,
+    global: &'static AllocCounter<T>,
+}
+
+// Ensure the counters are measured on thread destruction.
+impl<T: 'static + FixedCardinalityLabel + LabelGroup> Drop for ThreadState<T> {
+    fn drop(&mut self) {
+        // iterate over all labels
+        for tag in (0..T::cardinality()).map(T::decode) {
+            // load and reset the counts in the thread-local counters.
+            let m = self.counters.vec.get_metric_mut(tag);
+            let inc = *m.inc.count.get_mut();
+            let dec = *m.dec.count.get_mut();
+
+            // add the counts into the global counters.
+            let m = self.global.vec.get_metric(tag);
+            m.inc.count.fetch_add(inc, Relaxed);
+            m.dec.count.fetch_add(dec, Relaxed);
+        }
+    }
+}
+
+impl<A, T, Enc> MetricGroup<Enc> for TrackedAllocator<A, T>
+where
+    T: 'static + Send + Sync + FixedCardinalityLabel + LabelGroup,
+    Enc: Encoding,
+    CounterState: MetricEncoding<Enc>,
+{
+    fn collect_group_into(&self, enc: &mut Enc) -> Result<(), Enc::Err> {
+        let global = self.global.get_or_init(AllocCounter::new);
+
+        // iterate over all counter threads
+        for s in self.thread.get().into_iter().flat_map(|s| s.state.iter()) {
+            // iterate over all labels
+            for tag in (0..T::cardinality()).map(T::decode) {
+                sample(global, s.counters.vec.get_metric(tag), tag);
+            }
+        }
+
+        sample(global, &self.default_counters, self.default_tag);
+
+        global.collect_group_into(enc)
+    }
+}
+
+fn sample<T: FixedCardinalityLabel + LabelGroup>(
+    global: &AllocCounter<T>,
+    local: &MeasuredCounterPairState,
+    tag: T,
+) {
+    // load and reset the counts in the thread-local counters.
+    let inc = local.inc.count.swap(0, Relaxed);
+    let dec = local.dec.count.swap(0, Relaxed);
+
+    // add the counts into the global counters.
+    let m = global.vec.get_metric(tag);
+    m.inc.count.fetch_add(inc, Relaxed);
+    m.dec.count.fetch_add(dec, Relaxed);
+}
+
+#[cfg(test)]
+mod tests {
+    use std::alloc::{GlobalAlloc, Layout, System};
+
+    use measured::{FixedCardinalityLabel, MetricGroup, text::BufferedTextEncoder};
+
+    use crate::TrackedAllocator;
+
+    #[derive(FixedCardinalityLabel, Clone, Copy, Debug)]
+    #[label(singleton = "memory_context")]
+    pub enum MemoryContext {
+        Root,
+        Test,
+    }
+
+    #[test]
+    fn alloc() {
+        // Safety: `MemoryContext` upholds the safety requirements.
+        static GLOBAL: TrackedAllocator<System, MemoryContext> =
+            unsafe { TrackedAllocator::new(System, MemoryContext::Root) };
+
+        GLOBAL.register_thread();
+
+        let _test = GLOBAL.scope(MemoryContext::Test);
+
+        let ptr = unsafe { GLOBAL.alloc(Layout::for_value(&[0_i32])) };
+        let ptr = unsafe { GLOBAL.realloc(ptr, Layout::for_value(&[0_i32]), 8) };
+
+        drop(_test);
+
+        let ptr = unsafe { GLOBAL.realloc(ptr, Layout::for_value(&[0_i32, 1_i32]), 4) };
+        unsafe { GLOBAL.dealloc(ptr, Layout::for_value(&[0_i32])) };
+
+        let mut text = BufferedTextEncoder::new();
+        GLOBAL.collect_group_into(&mut text).unwrap();
+        let text = String::from_utf8(text.finish().into()).unwrap();
+        assert_eq!(
+            text,
+            r#"# HELP deallocated_bytes total number of bytes deallocated
+# TYPE deallocated_bytes counter
+deallocated_bytes{memory_context="root"} 4
+deallocated_bytes{memory_context="test"} 8
+
+# HELP allocated_bytes total number of bytes allocated
+# TYPE allocated_bytes counter
+allocated_bytes{memory_context="root"} 4
+allocated_bytes{memory_context="test"} 8
+"#
+        );
+    }
+
+    #[test]
+    fn unregistered_thread() {
+        // Safety: `MemoryContext` upholds the safety requirements.
+        static GLOBAL: TrackedAllocator<System, MemoryContext> =
+            unsafe { TrackedAllocator::new(System, MemoryContext::Root) };
+
+        GLOBAL.register_thread();
+
+        // unregistered thread
+        std::thread::spawn(|| {
+            let ptr = unsafe { GLOBAL.alloc(Layout::for_value(&[0_i32])) };
+            unsafe { GLOBAL.dealloc(ptr, Layout::for_value(&[0_i32])) };
+        })
+        .join()
+        .unwrap();
+
+        let mut text = BufferedTextEncoder::new();
+        GLOBAL.collect_group_into(&mut text).unwrap();
+        let text = String::from_utf8(text.finish().into()).unwrap();
+        assert_eq!(
+            text,
+            r#"# HELP deallocated_bytes total number of bytes deallocated
+# TYPE deallocated_bytes counter
+deallocated_bytes{memory_context="root"} 4
+deallocated_bytes{memory_context="test"} 0
+
+# HELP allocated_bytes total number of bytes allocated
+# TYPE allocated_bytes counter
+allocated_bytes{memory_context="root"} 4
+allocated_bytes{memory_context="test"} 0
+"#
+        );
+    }
+
+    #[test]
+    fn fully_unregistered() {
+        // Safety: `MemoryContext` upholds the safety requirements.
+        static GLOBAL: TrackedAllocator<System, MemoryContext> =
+            unsafe { TrackedAllocator::new(System, MemoryContext::Root) };
+
+        let ptr = unsafe { GLOBAL.alloc(Layout::for_value(&[0_i32])) };
+        unsafe { GLOBAL.dealloc(ptr, Layout::for_value(&[0_i32])) };
+
+        let mut text = BufferedTextEncoder::new();
+        GLOBAL.collect_group_into(&mut text).unwrap();
+        let text = String::from_utf8(text.finish().into()).unwrap();
+        assert_eq!(
+            text,
+            r#"# HELP deallocated_bytes total number of bytes deallocated
+# TYPE deallocated_bytes counter
+deallocated_bytes{memory_context="root"} 4
+deallocated_bytes{memory_context="test"} 0
+
+# HELP allocated_bytes total number of bytes allocated
+# TYPE allocated_bytes counter
+allocated_bytes{memory_context="root"} 4
+allocated_bytes{memory_context="test"} 0
+"#
+        );
+    }
+}

libs/alloc-metrics/src/metric_vec.rs

@@ -0,0 +1,72 @@
+//! Dense metric vec
+
+use measured::{
+    FixedCardinalityLabel, LabelGroup,
+    label::StaticLabelSet,
+    metric::{
+        MetricEncoding, MetricFamilyEncoding, MetricType, group::Encoding, name::MetricNameEncoder,
+    },
+};
+
+pub struct DenseMetricVec<M: MetricType, L: FixedCardinalityLabel + LabelGroup> {
+    metrics: Box<[M]>,
+    metadata: M::Metadata,
+    _label_set: StaticLabelSet<L>,
+}
+
+fn new_dense<M: MetricType>(c: usize) -> Box<[M]> {
+    let mut vec = Vec::with_capacity(c);
+    vec.resize_with(c, M::default);
+    vec.into_boxed_slice()
+}
+
+impl<M: MetricType, L: FixedCardinalityLabel + LabelGroup> DenseMetricVec<M, L>
+where
+    M::Metadata: Default,
+{
+    /// Create a new metric vec with the given label set and metric metadata
+    pub fn new() -> Self {
+        Self::with_metadata(<M::Metadata>::default())
+    }
+}
+
+impl<M: MetricType, L: FixedCardinalityLabel + LabelGroup> DenseMetricVec<M, L> {
+    /// Create a new metric vec with the given label set and metric metadata
+    pub fn with_metadata(metadata: M::Metadata) -> Self {
+        Self {
+            metrics: new_dense(L::cardinality()),
+            metadata,
+            _label_set: StaticLabelSet::new(),
+        }
+    }
+
+    /// Get the individual metric at the given identifier.
+    ///
+    /// # Panics
+    /// Can panic or cause strange behaviour if the label ID comes from a different metric family.
+    pub fn get_metric(&self, label: L) -> &M {
+        // safety: The caller has guarantees that the label encoding is valid.
+        unsafe { self.metrics.get_unchecked(label.encode()) }
+    }
+
+    /// Get the individual metric at the given identifier.
+    ///
+    /// # Panics
+    /// Can panic or cause strange behaviour if the label ID comes from a different metric family.
+    pub fn get_metric_mut(&mut self, label: L) -> &mut M {
+        // safety: The caller has guarantees that the label encoding is valid.
+        unsafe { self.metrics.get_unchecked_mut(label.encode()) }
+    }
+}
+
+impl<M: MetricEncoding<T>, L: FixedCardinalityLabel + LabelGroup, T: Encoding>
+    MetricFamilyEncoding<T> for DenseMetricVec<M, L>
+{
+    fn collect_family_into(&self, name: impl MetricNameEncoder, enc: &mut T) -> Result<(), T::Err> {
+        M::write_type(&name, enc)?;
+        for (index, value) in self.metrics.iter().enumerate() {
+            value.collect_into(&self.metadata, L::decode(index), &name, enc)?;
+        }
+        Ok(())
+    }
+}

libs/compute_api/src/responses.rs

@@ -46,16 +46,33 @@ pub struct ExtensionInstallResponse {
     pub version: ExtVersion,
 }
 
+/// Status of the LFC prewarm process. The same state machine is reused for
+/// both autoprewarm (prewarm after compute/Postgres start using the previously
+/// stored LFC state) and explicit prewarming via API.
 #[derive(Serialize, Default, Debug, Clone, PartialEq)]
 #[serde(tag = "status", rename_all = "snake_case")]
 pub enum LfcPrewarmState {
+    /// Default value when compute boots up.
     #[default]
     NotPrewarmed,
+    /// Prewarming thread is active and loading pages into LFC.
     Prewarming,
+    /// We found requested LFC state in the endpoint storage and
+    /// completed prewarming successfully.
     Completed,
-    Failed {
-        error: String,
-    },
+    /// Unexpected error happened during prewarming. Note, `Not Found 404`
+    /// response from the endpoint storage is explicitly excluded here
+    /// because it can normally happen on the first compute start,
+    /// since LFC state is not available yet.
+    Failed { error: String },
+    /// We tried to fetch the corresponding LFC state from the endpoint storage,
+    /// but received `Not Found 404`. This should normally happen only during the
+    /// first endpoint start after creation with `autoprewarm: true`.
+    ///
+    /// During the orchestrated prewarm via API, when a caller explicitly
+    /// provides the LFC state key to prewarm from, it's the caller responsibility
+    /// to handle this status as an error state in this case.
+    Skipped,
 }
 
 impl Display for LfcPrewarmState {
@@ -64,6 +81,7 @@ impl Display for LfcPrewarmState {
             LfcPrewarmState::NotPrewarmed => f.write_str("NotPrewarmed"),
             LfcPrewarmState::Prewarming => f.write_str("Prewarming"),
             LfcPrewarmState::Completed => f.write_str("Completed"),
+            LfcPrewarmState::Skipped => f.write_str("Skipped"),
             LfcPrewarmState::Failed { error } => write!(f, "Error({error})"),
         }
     }

libs/metrics/src/lib.rs

@@ -4,12 +4,14 @@
 //! a default registry.
 #![deny(clippy::undocumented_unsafe_blocks)]
 
+use std::sync::RwLock;
+
 use measured::label::{LabelGroupSet, LabelGroupVisitor, LabelName, NoLabels};
 use measured::metric::counter::CounterState;
 use measured::metric::gauge::GaugeState;
 use measured::metric::group::Encoding;
 use measured::metric::name::{MetricName, MetricNameEncoder};
-use measured::metric::{MetricEncoding, MetricFamilyEncoding};
+use measured::metric::{MetricEncoding, MetricFamilyEncoding, MetricType};
 use measured::{FixedCardinalityLabel, LabelGroup, MetricGroup};
 use once_cell::sync::Lazy;
 use prometheus::Registry;
@@ -116,12 +118,52 @@ pub fn pow2_buckets(start: usize, end: usize) -> Vec<f64> {
         .collect()
 }
 
+pub struct InfoMetric<L: LabelGroup, M: MetricType = GaugeState> {
+    label: RwLock<L>,
+    metric: M,
+}
+
+impl<L: LabelGroup> InfoMetric<L> {
+    pub fn new(label: L) -> Self {
+        Self::with_metric(label, GaugeState::new(1))
+    }
+}
+
+impl<L: LabelGroup, M: MetricType<Metadata = ()>> InfoMetric<L, M> {
+    pub fn with_metric(label: L, metric: M) -> Self {
+        Self {
+            label: RwLock::new(label),
+            metric,
+        }
+    }
+
+    pub fn set_label(&self, label: L) {
+        *self.label.write().unwrap() = label;
+    }
+}
+
+impl<L, M, E> MetricFamilyEncoding<E> for InfoMetric<L, M>
+where
+    L: LabelGroup,
+    M: MetricEncoding<E, Metadata = ()>,
+    E: Encoding,
+{
+    fn collect_family_into(
+        &self,
+        name: impl measured::metric::name::MetricNameEncoder,
+        enc: &mut E,
+    ) -> Result<(), E::Err> {
+        M::write_type(&name, enc)?;
+        self.metric
+            .collect_into(&(), &*self.label.read().unwrap(), name, enc)
+    }
+}
+
 pub struct BuildInfo {
     pub revision: &'static str,
     pub build_tag: &'static str,
 }
 
-// todo: allow label group without the set
 impl LabelGroup for BuildInfo {
     fn visit_values(&self, v: &mut impl LabelGroupVisitor) {
         const REVISION: &LabelName = LabelName::from_str("revision");
@@ -131,24 +173,6 @@ impl LabelGroup for BuildInfo {
     }
 }
 
-impl<T: Encoding> MetricFamilyEncoding<T> for BuildInfo
-where
-    GaugeState: MetricEncoding<T>,
-{
-    fn collect_family_into(
-        &self,
-        name: impl measured::metric::name::MetricNameEncoder,
-        enc: &mut T,
-    ) -> Result<(), T::Err> {
-        enc.write_help(&name, "Build/version information")?;
-        GaugeState::write_type(&name, enc)?;
-        GaugeState {
-            count: std::sync::atomic::AtomicI64::new(1),
-        }
-        .collect_into(&(), self, name, enc)
-    }
-}
-
 #[derive(MetricGroup)]
 #[metric(new(build_info: BuildInfo))]
 pub struct NeonMetrics {
@@ -165,8 +189,8 @@ pub struct NeonMetrics {
 #[derive(MetricGroup)]
 #[metric(new(build_info: BuildInfo))]
 pub struct LibMetrics {
-    #[metric(init = build_info)]
-    build_info: BuildInfo,
+    #[metric(init = InfoMetric::new(build_info))]
+    build_info: InfoMetric<BuildInfo>,
 
     #[metric(flatten)]
     rusage: Rusage,
@@ -454,7 +478,7 @@ pub trait CounterPairAssoc {
 }
 
 pub struct CounterPairVec<A: CounterPairAssoc> {
-    vec: measured::metric::MetricVec<MeasuredCounterPairState, A::LabelGroupSet>,
+    pub vec: measured::metric::MetricVec<MeasuredCounterPairState, A::LabelGroupSet>,
 }
 
 impl<A: CounterPairAssoc> Default for CounterPairVec<A>
@@ -468,6 +492,17 @@ where
     }
 }
 
+impl<A: CounterPairAssoc> CounterPairVec<A>
+where
+    A::LabelGroupSet: Default,
+{
+    pub fn dense() -> Self {
+        Self {
+            vec: measured::metric::MetricVec::dense(),
+        }
+    }
+}
+
 impl<A: CounterPairAssoc> CounterPairVec<A> {
     pub fn guard(
         &self,
@@ -477,14 +512,31 @@ impl<A: CounterPairAssoc> CounterPairVec<A> {
         self.vec.get_metric(id).inc.inc();
         MeasuredCounterPairGuard { vec: &self.vec, id }
     }
+
+    #[inline]
     pub fn inc(&self, labels: <A::LabelGroupSet as LabelGroupSet>::Group<'_>) {
         let id = self.vec.with_labels(labels);
         self.vec.get_metric(id).inc.inc();
     }
+
+    #[inline]
     pub fn dec(&self, labels: <A::LabelGroupSet as LabelGroupSet>::Group<'_>) {
         let id = self.vec.with_labels(labels);
         self.vec.get_metric(id).dec.inc();
     }
+
+    #[inline]
+    pub fn inc_by(&self, labels: <A::LabelGroupSet as LabelGroupSet>::Group<'_>, x: u64) {
+        let id = self.vec.with_labels(labels);
+        self.vec.get_metric(id).inc.inc_by(x);
+    }
+
+    #[inline]
+    pub fn dec_by(&self, labels: <A::LabelGroupSet as LabelGroupSet>::Group<'_>, x: u64) {
+        let id = self.vec.with_labels(labels);
+        self.vec.get_metric(id).dec.inc_by(x);
+    }
+
     pub fn remove_metric(
         &self,
         labels: <A::LabelGroupSet as LabelGroupSet>::Group<'_>,
@@ -529,6 +581,28 @@ pub struct MeasuredCounterPairState {
     pub dec: CounterState,
 }
 
+impl MeasuredCounterPairState {
+    #[inline]
+    pub fn inc(&self) {
+        self.inc.inc();
+    }
+
+    #[inline]
+    pub fn dec(&self) {
+        self.dec.inc();
+    }
+
+    #[inline]
+    pub fn inc_by(&self, x: u64) {
+        self.inc.inc_by(x);
+    }
+
+    #[inline]
+    pub fn dec_by(&self, x: u64) {
+        self.dec.inc_by(x);
+    }
+}
+
 impl measured::metric::MetricType for MeasuredCounterPairState {
     type Metadata = ();
 }
@@ -545,9 +619,9 @@ impl<A: CounterPairAssoc> Drop for MeasuredCounterPairGuard<'_, A> {
 }
 
 /// [`MetricEncoding`] for [`MeasuredCounterPairState`] that only writes the inc counter to the inner encoder.
-struct Inc<T>(T);
+pub struct Inc<T>(pub T);
 /// [`MetricEncoding`] for [`MeasuredCounterPairState`] that only writes the dec counter to the inner encoder.
-struct Dec<T>(T);
+pub struct Dec<T>(pub T);
 
 impl<T: Encoding> Encoding for Inc<T> {
     type Err = T::Err;

libs/neon-shmem/Cargo.toml

@@ -8,6 +8,13 @@ license.workspace = true
 thiserror.workspace = true
 nix.workspace=true
 workspace_hack = { version = "0.1", path = "../../workspace_hack" }
+libc.workspace = true
+lock_api.workspace = true
+rustc-hash.workspace = true
 
 [target.'cfg(target_os = "macos")'.dependencies]
 tempfile = "3.14.0"
+
+[dev-dependencies]
+rand = "0.9"
+rand_distr = "0.5.1"

libs/neon-shmem/src/hash.rs

@@ -0,0 +1,583 @@
+//! Resizable hash table implementation on top of byte-level storage (either a [`ShmemHandle`] or a fixed byte array).
+//!
+//! This hash table has two major components: the bucket array and the dictionary. Each bucket within the
+//! bucket array contains a `Option<(K, V)>` and an index of another bucket. In this way there is both an
+//! implicit freelist within the bucket array (`None` buckets point to other `None` entries) and various hash
+//! chains within the bucket array (a Some bucket will point to other Some buckets that had the same hash).
+//!
+//! Buckets are never moved unless they are within a region that is being shrunk, and so the actual hash-
+//! dependent component is done with the dictionary. When a new key is inserted into the map, a position
+//! within the dictionary is decided based on its hash, the data is inserted into an empty bucket based
+//! off of the freelist, and then the index of said bucket is placed in the dictionary.
+//!
+//! This map is resizable (if initialized on top of a [`ShmemHandle`]). Both growing and shrinking happen
+//! in-place and are at a high level achieved by expanding/reducing the bucket array and rebuilding the
+//! dictionary by rehashing all keys.
+//!
+//! Concurrency is managed very simply: the entire map is guarded by one shared-memory RwLock.
+
+use std::hash::{BuildHasher, Hash};
+use std::mem::MaybeUninit;
+
+use crate::shmem::ShmemHandle;
+use crate::{shmem, sync::*};
+
+mod core;
+pub mod entry;
+
+#[cfg(test)]
+mod tests;
+
+use core::{Bucket, CoreHashMap, INVALID_POS};
+use entry::{Entry, OccupiedEntry, PrevPos, VacantEntry};
+
+use thiserror::Error;
+
+/// Error type for a hashmap shrink operation.
+#[derive(Error, Debug)]
+pub enum HashMapShrinkError {
+    /// There was an error encountered while resizing the memory area.
+    #[error("shmem resize failed: {0}")]
+    ResizeError(shmem::Error),
+    /// Occupied entries in to-be-shrunk space were encountered beginning at the given index.
+    #[error("occupied entry in deallocated space found at {0}")]
+    RemainingEntries(usize),
+}
+
+/// This represents a hash table that (possibly) lives in shared memory.
+/// If a new process is launched with fork(), the child process inherits
+/// this struct.
+#[must_use]
+pub struct HashMapInit<'a, K, V, S = rustc_hash::FxBuildHasher> {
+    shmem_handle: Option<ShmemHandle>,
+    shared_ptr: *mut HashMapShared<'a, K, V>,
+    shared_size: usize,
+    hasher: S,
+    num_buckets: u32,
+}
+
+/// This is a per-process handle to a hash table that (possibly) lives in shared memory.
+/// If a child process is launched with fork(), the child process should
+/// get its own HashMapAccess by calling HashMapInit::attach_writer/reader().
+///
+/// XXX: We're not making use of it at the moment, but this struct could
+/// hold process-local information in the future.
+pub struct HashMapAccess<'a, K, V, S = rustc_hash::FxBuildHasher> {
+    shmem_handle: Option<ShmemHandle>,
+    shared_ptr: *mut HashMapShared<'a, K, V>,
+    hasher: S,
+}
+
+unsafe impl<K: Sync, V: Sync, S> Sync for HashMapAccess<'_, K, V, S> {}
+unsafe impl<K: Send, V: Send, S> Send for HashMapAccess<'_, K, V, S> {}
+
+impl<'a, K: Clone + Hash + Eq, V, S> HashMapInit<'a, K, V, S> {
+    /// Change the 'hasher' used by the hash table.
+    ///
+    /// NOTE: This must be called right after creating the hash table,
+    /// before inserting any entries and before calling attach_writer/reader.
+    /// Otherwise different accessors could be using different hash function,
+    /// with confusing results.
+    pub fn with_hasher<T: BuildHasher>(self, hasher: T) -> HashMapInit<'a, K, V, T> {
+        HashMapInit {
+            hasher,
+            shmem_handle: self.shmem_handle,
+            shared_ptr: self.shared_ptr,
+            shared_size: self.shared_size,
+            num_buckets: self.num_buckets,
+        }
+    }
+
+    /// Loosely (over)estimate the size needed to store a hash table with `num_buckets` buckets.
+    pub fn estimate_size(num_buckets: u32) -> usize {
+        // add some margin to cover alignment etc.
+        CoreHashMap::<K, V>::estimate_size(num_buckets) + size_of::<HashMapShared<K, V>>() + 1000
+    }
+
+    fn new(
+        num_buckets: u32,
+        shmem_handle: Option<ShmemHandle>,
+        area_ptr: *mut u8,
+        area_size: usize,
+        hasher: S,
+    ) -> Self {
+        let mut ptr: *mut u8 = area_ptr;
+        let end_ptr: *mut u8 = unsafe { ptr.add(area_size) };
+
+        // carve out area for the One Big Lock (TM) and the HashMapShared.
+        ptr = unsafe { ptr.add(ptr.align_offset(align_of::<libc::pthread_rwlock_t>())) };
+        let raw_lock_ptr = ptr;
+        ptr = unsafe { ptr.add(size_of::<libc::pthread_rwlock_t>()) };
+        ptr = unsafe { ptr.add(ptr.align_offset(align_of::<HashMapShared<K, V>>())) };
+        let shared_ptr: *mut HashMapShared<K, V> = ptr.cast();
+        ptr = unsafe { ptr.add(size_of::<HashMapShared<K, V>>()) };
+
+        // carve out the buckets
+        ptr = unsafe { ptr.byte_add(ptr.align_offset(align_of::<core::Bucket<K, V>>())) };
+        let buckets_ptr = ptr;
+        ptr = unsafe { ptr.add(size_of::<core::Bucket<K, V>>() * num_buckets as usize) };
+
+        // use remaining space for the dictionary
+        ptr = unsafe { ptr.byte_add(ptr.align_offset(align_of::<u32>())) };
+        assert!(ptr.addr() < end_ptr.addr());
+        let dictionary_ptr = ptr;
+        let dictionary_size = unsafe { end_ptr.byte_offset_from(ptr) / size_of::<u32>() as isize };
+        assert!(dictionary_size > 0);
+
+        let buckets =
+            unsafe { std::slice::from_raw_parts_mut(buckets_ptr.cast(), num_buckets as usize) };
+        let dictionary = unsafe {
+            std::slice::from_raw_parts_mut(dictionary_ptr.cast(), dictionary_size as usize)
+        };
+
+        let hashmap = CoreHashMap::new(buckets, dictionary);
+        unsafe {
+            let lock = RwLock::from_raw(PthreadRwLock::new(raw_lock_ptr.cast()), hashmap);
+            std::ptr::write(shared_ptr, lock);
+        }
+
+        Self {
+            num_buckets,
+            shmem_handle,
+            shared_ptr,
+            shared_size: area_size,
+            hasher,
+        }
+    }
+
+    /// Attach to a hash table for writing.
+    pub fn attach_writer(self) -> HashMapAccess<'a, K, V, S> {
+        HashMapAccess {
+            shmem_handle: self.shmem_handle,
+            shared_ptr: self.shared_ptr,
+            hasher: self.hasher,
+        }
+    }
+
+    /// Initialize a table for reading. Currently identical to [`HashMapInit::attach_writer`].
+    ///
+    /// This is a holdover from a previous implementation and is being kept around for
+    /// backwards compatibility reasons.
+    pub fn attach_reader(self) -> HashMapAccess<'a, K, V, S> {
+        self.attach_writer()
+    }
+}
+
+/// Hash table data that is actually stored in the shared memory area.
+///
+/// NOTE: We carve out the parts from a contiguous chunk. Growing and shrinking the hash table
+/// relies on the memory layout! The data structures are laid out in the contiguous shared memory
+/// area as follows:
+///
+/// [`libc::pthread_rwlock_t`]
+/// [`HashMapShared`]
+/// buckets
+/// dictionary
+///
+/// In between the above parts, there can be padding bytes to align the parts correctly.
+type HashMapShared<'a, K, V> = RwLock<CoreHashMap<'a, K, V>>;
+
+impl<'a, K, V> HashMapInit<'a, K, V, rustc_hash::FxBuildHasher>
+where
+    K: Clone + Hash + Eq,
+{
+    /// Place the hash table within a user-supplied fixed memory area.
+    pub fn with_fixed(num_buckets: u32, area: &'a mut [MaybeUninit<u8>]) -> Self {
+        Self::new(
+            num_buckets,
+            None,
+            area.as_mut_ptr().cast(),
+            area.len(),
+            rustc_hash::FxBuildHasher,
+        )
+    }
+
+    /// Place a new hash map in the given shared memory area
+    ///
+    /// # Panics
+    /// Will panic on failure to resize area to expected map size.
+    pub fn with_shmem(num_buckets: u32, shmem: ShmemHandle) -> Self {
+        let size = Self::estimate_size(num_buckets);
+        shmem
+            .set_size(size)
+            .expect("could not resize shared memory area");
+        let ptr = shmem.data_ptr.as_ptr().cast();
+        Self::new(
+            num_buckets,
+            Some(shmem),
+            ptr,
+            size,
+            rustc_hash::FxBuildHasher,
+        )
+    }
+
+    /// Make a resizable hash map within a new shared memory area with the given name.
+    pub fn new_resizeable_named(num_buckets: u32, max_buckets: u32, name: &str) -> Self {
+        let size = Self::estimate_size(num_buckets);
+        let max_size = Self::estimate_size(max_buckets);
+        let shmem =
+            ShmemHandle::new(name, size, max_size).expect("failed to make shared memory area");
+        let ptr = shmem.data_ptr.as_ptr().cast();
+
+        Self::new(
+            num_buckets,
+            Some(shmem),
+            ptr,
+            size,
+            rustc_hash::FxBuildHasher,
+        )
+    }
+
+    /// Make a resizable hash map within a new anonymous shared memory area.
+    pub fn new_resizeable(num_buckets: u32, max_buckets: u32) -> Self {
+        use std::sync::atomic::{AtomicUsize, Ordering};
+        static COUNTER: AtomicUsize = AtomicUsize::new(0);
+        let val = COUNTER.fetch_add(1, Ordering::Relaxed);
+        let name = format!("neon_shmem_hmap{val}");
+        Self::new_resizeable_named(num_buckets, max_buckets, &name)
+    }
+}
+
+impl<'a, K, V, S: BuildHasher> HashMapAccess<'a, K, V, S>
+where
+    K: Clone + Hash + Eq,
+{
+    /// Hash a key using the map's hasher.
+    #[inline]
+    fn get_hash_value(&self, key: &K) -> u64 {
+        self.hasher.hash_one(key)
+    }
+
+    fn entry_with_hash(&self, key: K, hash: u64) -> Entry<'a, '_, K, V> {
+        let mut map = unsafe { self.shared_ptr.as_ref() }.unwrap().write();
+        let dict_pos = hash as usize % map.dictionary.len();
+        let first = map.dictionary[dict_pos];
+        if first == INVALID_POS {
+            // no existing entry
+            return Entry::Vacant(VacantEntry {
+                map,
+                key,
+                dict_pos: dict_pos as u32,
+            });
+        }
+
+        let mut prev_pos = PrevPos::First(dict_pos as u32);
+        let mut next = first;
+        loop {
+            let bucket = &mut map.buckets[next as usize];
+            let (bucket_key, _bucket_value) = bucket.inner.as_mut().expect("entry is in use");
+            if *bucket_key == key {
+                // found existing entry
+                return Entry::Occupied(OccupiedEntry {
+                    map,
+                    _key: key,
+                    prev_pos,
+                    bucket_pos: next,
+                });
+            }
+
+            if bucket.next == INVALID_POS {
+                // No existing entry
+                return Entry::Vacant(VacantEntry {
+                    map,
+                    key,
+                    dict_pos: dict_pos as u32,
+                });
+            }
+            prev_pos = PrevPos::Chained(next);
+            next = bucket.next;
+        }
+    }
+
+    /// Get a reference to the corresponding value for a key.
+    pub fn get<'e>(&'e self, key: &K) -> Option<ValueReadGuard<'e, V>> {
+        let hash = self.get_hash_value(key);
+        let map = unsafe { self.shared_ptr.as_ref() }.unwrap().read();
+        RwLockReadGuard::try_map(map, |m| m.get_with_hash(key, hash)).ok()
+    }
+
+    /// Get a reference to the entry containing a key.
+    ///
+    /// NB: THis takes a write lock as there's no way to distinguish whether the intention
+    /// is to use the entry for reading or for writing in advance.
+    pub fn entry(&self, key: K) -> Entry<'a, '_, K, V> {
+        let hash = self.get_hash_value(&key);
+        self.entry_with_hash(key, hash)
+    }
+
+    /// Remove a key given its hash. Returns the associated value if it existed.
+    pub fn remove(&self, key: &K) -> Option<V> {
+        let hash = self.get_hash_value(key);
+        match self.entry_with_hash(key.clone(), hash) {
+            Entry::Occupied(e) => Some(e.remove()),
+            Entry::Vacant(_) => None,
+        }
+    }
+
+    /// Insert/update a key. Returns the previous associated value if it existed.
+    ///
+    /// # Errors
+    /// Will return [`core::FullError`] if there is no more space left in the map.
+    pub fn insert(&self, key: K, value: V) -> Result<Option<V>, core::FullError> {
+        let hash = self.get_hash_value(&key);
+        match self.entry_with_hash(key.clone(), hash) {
+            Entry::Occupied(mut e) => Ok(Some(e.insert(value))),
+            Entry::Vacant(e) => {
+                _ = e.insert(value)?;
+                Ok(None)
+            }
+        }
+    }
+
+    /// Optionally return the entry for a bucket at a given index if it exists.
+    ///
+    /// Has more overhead than one would intuitively expect: performs both a clone of the key
+    /// due to the [`OccupiedEntry`] type owning the key and also a hash of the key in order
+    /// to enable repairing the hash chain if the entry is removed.
+    pub fn entry_at_bucket(&self, pos: usize) -> Option<OccupiedEntry<'a, '_, K, V>> {
+        let map = unsafe { self.shared_ptr.as_mut() }.unwrap().write();
+        if pos >= map.buckets.len() {
+            return None;
+        }
+
+        let entry = map.buckets[pos].inner.as_ref();
+        match entry {
+            Some((key, _)) => Some(OccupiedEntry {
+                _key: key.clone(),
+                bucket_pos: pos as u32,
+                prev_pos: entry::PrevPos::Unknown(self.get_hash_value(key)),
+                map,
+            }),
+            _ => None,
+        }
+    }
+
+    /// Returns the number of buckets in the table.
+    pub fn get_num_buckets(&self) -> usize {
+        let map = unsafe { self.shared_ptr.as_ref() }.unwrap().read();
+        map.get_num_buckets()
+    }
+
+    /// Return the key and value stored in bucket with given index. This can be used to
+    /// iterate through the hash map.
+    // TODO: An Iterator might be nicer. The communicator's clock algorithm needs to
+    // _slowly_ iterate through all buckets with its clock hand,  without holding a lock.
+    // If we switch to an Iterator, it must not hold the lock.
+    pub fn get_at_bucket(&self, pos: usize) -> Option<ValueReadGuard<(K, V)>> {
+        let map = unsafe { self.shared_ptr.as_ref() }.unwrap().read();
+        if pos >= map.buckets.len() {
+            return None;
+        }
+        RwLockReadGuard::try_map(map, |m| m.buckets[pos].inner.as_ref()).ok()
+    }
+
+    /// Returns the index of the bucket a given value corresponds to.
+    pub fn get_bucket_for_value(&self, val_ptr: *const V) -> usize {
+        let map = unsafe { self.shared_ptr.as_ref() }.unwrap().read();
+
+        let origin = map.buckets.as_ptr();
+        let idx = (val_ptr as usize - origin as usize) / size_of::<Bucket<K, V>>();
+        assert!(idx < map.buckets.len());
+
+        idx
+    }
+
+    /// Returns the number of occupied buckets in the table.
+    pub fn get_num_buckets_in_use(&self) -> usize {
+        let map = unsafe { self.shared_ptr.as_ref() }.unwrap().read();
+        map.buckets_in_use as usize
+    }
+
+    /// Clears all entries in a table. Does not reset any shrinking operations.
+    pub fn clear(&self) {
+        let mut map = unsafe { self.shared_ptr.as_mut() }.unwrap().write();
+        map.clear();
+    }
+
+    /// Perform an in-place rehash of some region (0..`rehash_buckets`) of the table and reset
+    /// the `buckets` and `dictionary` slices to be as long as `num_buckets`. Resets the freelist
+    /// in the process.
+    fn rehash_dict(
+        &self,
+        inner: &mut CoreHashMap<'a, K, V>,
+        buckets_ptr: *mut core::Bucket<K, V>,
+        end_ptr: *mut u8,
+        num_buckets: u32,
+        rehash_buckets: u32,
+    ) {
+        inner.free_head = INVALID_POS;
+
+        let buckets;
+        let dictionary;
+        unsafe {
+            let buckets_end_ptr = buckets_ptr.add(num_buckets as usize);
+            let dictionary_ptr: *mut u32 = buckets_end_ptr
+                .byte_add(buckets_end_ptr.align_offset(align_of::<u32>()))
+                .cast();
+            let dictionary_size: usize =
+                end_ptr.byte_offset_from(buckets_end_ptr) as usize / size_of::<u32>();
+
+            buckets = std::slice::from_raw_parts_mut(buckets_ptr, num_buckets as usize);
+            dictionary = std::slice::from_raw_parts_mut(dictionary_ptr, dictionary_size);
+        }
+        for e in dictionary.iter_mut() {
+            *e = INVALID_POS;
+        }
+
+        for (i, bucket) in buckets.iter_mut().enumerate().take(rehash_buckets as usize) {
+            if bucket.inner.is_none() {
+                bucket.next = inner.free_head;
+                inner.free_head = i as u32;
+                continue;
+            }
+
+            let hash = self.hasher.hash_one(&bucket.inner.as_ref().unwrap().0);
+            let pos: usize = (hash % dictionary.len() as u64) as usize;
+            bucket.next = dictionary[pos];
+            dictionary[pos] = i as u32;
+        }
+
+        inner.dictionary = dictionary;
+        inner.buckets = buckets;
+    }
+
+    /// Rehash the map without growing or shrinking.
+    pub fn shuffle(&self) {
+        let mut map = unsafe { self.shared_ptr.as_mut() }.unwrap().write();
+        let num_buckets = map.get_num_buckets() as u32;
+        let size_bytes = HashMapInit::<K, V, S>::estimate_size(num_buckets);
+        let end_ptr: *mut u8 = unsafe { self.shared_ptr.byte_add(size_bytes).cast() };
+        let buckets_ptr = map.buckets.as_mut_ptr();
+        self.rehash_dict(&mut map, buckets_ptr, end_ptr, num_buckets, num_buckets);
+    }
+
+    /// Grow the number of buckets within the table.
+    ///
+    /// 1. Grows the underlying shared memory area
+    /// 2. Initializes new buckets and overwrites the current dictionary
+    /// 3. Rehashes the dictionary
+    ///
+    /// # Panics
+    /// Panics if called on a map initialized with [`HashMapInit::with_fixed`].
+    ///
+    /// # Errors
+    /// Returns an [`shmem::Error`] if any errors occur resizing the memory region.
+    pub fn grow(&self, num_buckets: u32) -> Result<(), shmem::Error> {
+        let mut map = unsafe { self.shared_ptr.as_mut() }.unwrap().write();
+        let old_num_buckets = map.buckets.len() as u32;
+
+        assert!(
+            num_buckets >= old_num_buckets,
+            "grow called with a smaller number of buckets"
+        );
+        if num_buckets == old_num_buckets {
+            return Ok(());
+        }
+        let shmem_handle = self
+            .shmem_handle
+            .as_ref()
+            .expect("grow called on a fixed-size hash table");
+
+        let size_bytes = HashMapInit::<K, V, S>::estimate_size(num_buckets);
+        shmem_handle.set_size(size_bytes)?;
+        let end_ptr: *mut u8 = unsafe { shmem_handle.data_ptr.as_ptr().add(size_bytes) };
+
+        // Initialize new buckets. The new buckets are linked to the free list.
+        // NB: This overwrites the dictionary!
+        let buckets_ptr = map.buckets.as_mut_ptr();
+        unsafe {
+            for i in old_num_buckets..num_buckets {
+                let bucket = buckets_ptr.add(i as usize);
+                bucket.write(core::Bucket {
+                    next: if i < num_buckets - 1 {
+                        i + 1
+                    } else {
+                        map.free_head
+                    },
+                    inner: None,
+                });
+            }
+        }
+
+        self.rehash_dict(&mut map, buckets_ptr, end_ptr, num_buckets, old_num_buckets);
+        map.free_head = old_num_buckets;
+
+        Ok(())
+    }
+
+    /// Begin a shrink, limiting all new allocations to be in buckets with index below `num_buckets`.
+    ///
+    /// # Panics
+    /// Panics if called on a map initialized with [`HashMapInit::with_fixed`] or if `num_buckets` is
+    /// greater than the number of buckets in the map.
+    pub fn begin_shrink(&mut self, num_buckets: u32) {
+        let mut map = unsafe { self.shared_ptr.as_mut() }.unwrap().write();
+        assert!(
+            num_buckets <= map.get_num_buckets() as u32,
+            "shrink called with a larger number of buckets"
+        );
+        _ = self
+            .shmem_handle
+            .as_ref()
+            .expect("shrink called on a fixed-size hash table");
+        map.alloc_limit = num_buckets;
+    }
+
+    /// If a shrink operation is underway, returns the target size of the map. Otherwise, returns None.
+    pub fn shrink_goal(&self) -> Option<usize> {
+        let map = unsafe { self.shared_ptr.as_mut() }.unwrap().read();
+        let goal = map.alloc_limit;
+        if goal == INVALID_POS {
+            None
+        } else {
+            Some(goal as usize)
+        }
+    }
+
+    /// Complete a shrink after caller has evicted entries, removing the unused buckets and rehashing.
+    ///
+    /// # Panics
+    /// The following cases result in a panic:
+    /// - Calling this function on a map initialized with [`HashMapInit::with_fixed`].
+    /// - Calling this function on a map when no shrink operation is in progress.
+    pub fn finish_shrink(&self) -> Result<(), HashMapShrinkError> {
+        let mut map = unsafe { self.shared_ptr.as_mut() }.unwrap().write();
+        assert!(
+            map.alloc_limit != INVALID_POS,
+            "called finish_shrink when no shrink is in progress"
+        );
+
+        let num_buckets = map.alloc_limit;
+
+        if map.get_num_buckets() == num_buckets as usize {
+            return Ok(());
+        }
+
+        assert!(
+            map.buckets_in_use <= num_buckets,
+            "called finish_shrink before enough entries were removed"
+        );
+
+        for i in (num_buckets as usize)..map.buckets.len() {
+            if map.buckets[i].inner.is_some() {
+                return Err(HashMapShrinkError::RemainingEntries(i));
+            }
+        }
+
+        let shmem_handle = self
+            .shmem_handle
+            .as_ref()
+            .expect("shrink called on a fixed-size hash table");
+
+        let size_bytes = HashMapInit::<K, V, S>::estimate_size(num_buckets);
+        if let Err(e) = shmem_handle.set_size(size_bytes) {
+            return Err(HashMapShrinkError::ResizeError(e));
+        }
+        let end_ptr: *mut u8 = unsafe { shmem_handle.data_ptr.as_ptr().add(size_bytes) };
+        let buckets_ptr = map.buckets.as_mut_ptr();
+        self.rehash_dict(&mut map, buckets_ptr, end_ptr, num_buckets, num_buckets);
+        map.alloc_limit = INVALID_POS;
+
+        Ok(())
+    }
+}

libs/neon-shmem/src/hash/core.rs

@@ -0,0 +1,174 @@
+//! Simple hash table with chaining.
+
+use std::hash::Hash;
+use std::mem::MaybeUninit;
+
+use crate::hash::entry::*;
+
+/// Invalid position within the map (either within the dictionary or bucket array).
+pub(crate) const INVALID_POS: u32 = u32::MAX;
+
+/// Fundamental storage unit within the hash table. Either empty or contains a key-value pair.
+/// Always part of a chain of some kind (either a freelist if empty or a hash chain if full).
+pub(crate) struct Bucket<K, V> {
+    /// Index of next bucket in the chain.
+    pub(crate) next: u32,
+    /// Key-value pair contained within bucket.
+    pub(crate) inner: Option<(K, V)>,
+}
+
+/// Core hash table implementation.
+pub(crate) struct CoreHashMap<'a, K, V> {
+    /// Dictionary used to map hashes to bucket indices.
+    pub(crate) dictionary: &'a mut [u32],
+    /// Buckets containing key-value pairs.
+    pub(crate) buckets: &'a mut [Bucket<K, V>],
+    /// Head of the freelist.
+    pub(crate) free_head: u32,
+    /// Maximum index of a bucket allowed to be allocated. [`INVALID_POS`] if no limit.
+    pub(crate) alloc_limit: u32,
+    /// The number of currently occupied buckets.
+    pub(crate) buckets_in_use: u32,
+}
+
+/// Error for when there are no empty buckets left but one is needed.
+#[derive(Debug, PartialEq)]
+pub struct FullError;
+
+impl<'a, K: Clone + Hash + Eq, V> CoreHashMap<'a, K, V> {
+    const FILL_FACTOR: f32 = 0.60;
+
+    /// Estimate the size of data contained within the the hash map.
+    pub fn estimate_size(num_buckets: u32) -> usize {
+        let mut size = 0;
+
+        // buckets
+        size += size_of::<Bucket<K, V>>() * num_buckets as usize;
+
+        // dictionary
+        size += (f32::ceil((size_of::<u32>() * num_buckets as usize) as f32 / Self::FILL_FACTOR))
+            as usize;
+
+        size
+    }
+
+    pub fn new(
+        buckets: &'a mut [MaybeUninit<Bucket<K, V>>],
+        dictionary: &'a mut [MaybeUninit<u32>],
+    ) -> Self {
+        // Initialize the buckets
+        for i in 0..buckets.len() {
+            buckets[i].write(Bucket {
+                next: if i < buckets.len() - 1 {
+                    i as u32 + 1
+                } else {
+                    INVALID_POS
+                },
+                inner: None,
+            });
+        }
+
+        // Initialize the dictionary
+        for e in dictionary.iter_mut() {
+            e.write(INVALID_POS);
+        }
+
+        // TODO: use std::slice::assume_init_mut() once it stabilizes
+        let buckets =
+            unsafe { std::slice::from_raw_parts_mut(buckets.as_mut_ptr().cast(), buckets.len()) };
+        let dictionary = unsafe {
+            std::slice::from_raw_parts_mut(dictionary.as_mut_ptr().cast(), dictionary.len())
+        };
+
+        Self {
+            dictionary,
+            buckets,
+            free_head: 0,
+            buckets_in_use: 0,
+            alloc_limit: INVALID_POS,
+        }
+    }
+
+    /// Get the value associated with a key (if it exists) given its hash.
+    pub fn get_with_hash(&self, key: &K, hash: u64) -> Option<&V> {
+        let mut next = self.dictionary[hash as usize % self.dictionary.len()];
+        loop {
+            if next == INVALID_POS {
+                return None;
+            }
+
+            let bucket = &self.buckets[next as usize];
+            let (bucket_key, bucket_value) = bucket.inner.as_ref().expect("entry is in use");
+            if bucket_key == key {
+                return Some(bucket_value);
+            }
+            next = bucket.next;
+        }
+    }
+
+    /// Get number of buckets in map.
+    pub fn get_num_buckets(&self) -> usize {
+        self.buckets.len()
+    }
+
+    /// Clears all entries from the hashmap.
+    ///
+    /// Does not reset any allocation limits, but does clear any entries beyond them.
+    pub fn clear(&mut self) {
+        for i in 0..self.buckets.len() {
+            self.buckets[i] = Bucket {
+                next: if i < self.buckets.len() - 1 {
+                    i as u32 + 1
+                } else {
+                    INVALID_POS
+                },
+                inner: None,
+            }
+        }
+        for i in 0..self.dictionary.len() {
+            self.dictionary[i] = INVALID_POS;
+        }
+
+        self.free_head = 0;
+        self.buckets_in_use = 0;
+    }
+
+    /// Find the position of an unused bucket via the freelist and initialize it.
+    pub(crate) fn alloc_bucket(&mut self, key: K, value: V) -> Result<u32, FullError> {
+        let mut pos = self.free_head;
+
+        // Find the first bucket we're *allowed* to use.
+        let mut prev = PrevPos::First(self.free_head);
+        while pos != INVALID_POS && pos >= self.alloc_limit {
+            let bucket = &mut self.buckets[pos as usize];
+            prev = PrevPos::Chained(pos);
+            pos = bucket.next;
+        }
+        if pos == INVALID_POS {
+            return Err(FullError);
+        }
+
+        // Repair the freelist.
+        match prev {
+            PrevPos::First(_) => {
+                let next_pos = self.buckets[pos as usize].next;
+                self.free_head = next_pos;
+            }
+            PrevPos::Chained(p) => {
+                if p != INVALID_POS {
+                    let next_pos = self.buckets[pos as usize].next;
+                    self.buckets[p as usize].next = next_pos;
+                }
+            }
+            _ => unreachable!(),
+        }
+
+        // Initialize the bucket.
+        let bucket = &mut self.buckets[pos as usize];
+        self.buckets_in_use += 1;
+        bucket.next = INVALID_POS;
+        bucket.inner = Some((key, value));
+
+        Ok(pos)
+    }
+}

libs/neon-shmem/src/hash/entry.rs

@@ -0,0 +1,130 @@
+//! Equivalent of [`std::collections::hash_map::Entry`] for this hashmap.
+
+use crate::hash::core::{CoreHashMap, FullError, INVALID_POS};
+use crate::sync::{RwLockWriteGuard, ValueWriteGuard};
+
+use std::hash::Hash;
+use std::mem;
+
+pub enum Entry<'a, 'b, K, V> {
+    Occupied(OccupiedEntry<'a, 'b, K, V>),
+    Vacant(VacantEntry<'a, 'b, K, V>),
+}
+
+/// Enum representing the previous position within a chain.
+#[derive(Clone, Copy)]
+pub(crate) enum PrevPos {
+    /// Starting index within the dictionary.  
+    First(u32),
+    /// Regular index within the buckets.
+    Chained(u32),
+    /// Unknown - e.g. the associated entry was retrieved by index instead of chain.
+    Unknown(u64),
+}
+
+pub struct OccupiedEntry<'a, 'b, K, V> {
+    /// Mutable reference to the map containing this entry.
+    pub(crate) map: RwLockWriteGuard<'b, CoreHashMap<'a, K, V>>,
+    /// The key of the occupied entry
+    pub(crate) _key: K,
+    /// The index of the previous entry in the chain.
+    pub(crate) prev_pos: PrevPos,
+    /// The position of the bucket in the [`CoreHashMap`] bucket array.
+    pub(crate) bucket_pos: u32,
+}
+
+impl<K, V> OccupiedEntry<'_, '_, K, V> {
+    pub fn get(&self) -> &V {
+        &self.map.buckets[self.bucket_pos as usize]
+            .inner
+            .as_ref()
+            .unwrap()
+            .1
+    }
+
+    pub fn get_mut(&mut self) -> &mut V {
+        &mut self.map.buckets[self.bucket_pos as usize]
+            .inner
+            .as_mut()
+            .unwrap()
+            .1
+    }
+
+    /// Inserts a value into the entry, replacing (and returning) the existing value.
+    pub fn insert(&mut self, value: V) -> V {
+        let bucket = &mut self.map.buckets[self.bucket_pos as usize];
+        // This assumes inner is Some, which it must be for an OccupiedEntry
+        mem::replace(&mut bucket.inner.as_mut().unwrap().1, value)
+    }
+
+    /// Removes the entry from the hash map, returning the value originally stored within it.
+    ///
+    /// This may result in multiple bucket accesses if the entry was obtained by index as the
+    /// previous chain entry needs to be discovered in this case.
+    pub fn remove(mut self) -> V {
+        // If this bucket was queried by index, go ahead and follow its chain from the start.
+        let prev = if let PrevPos::Unknown(hash) = self.prev_pos {
+            let dict_idx = hash as usize % self.map.dictionary.len();
+            let mut prev = PrevPos::First(dict_idx as u32);
+            let mut curr = self.map.dictionary[dict_idx];
+            while curr != self.bucket_pos {
+                assert!(curr != INVALID_POS);
+                prev = PrevPos::Chained(curr);
+                curr = self.map.buckets[curr as usize].next;
+            }
+            prev
+        } else {
+            self.prev_pos
+        };
+
+        // CoreHashMap::remove returns Option<(K, V)>. We know it's Some for an OccupiedEntry.
+        let bucket = &mut self.map.buckets[self.bucket_pos as usize];
+
+        // unlink it from the chain
+        match prev {
+            PrevPos::First(dict_pos) => {
+                self.map.dictionary[dict_pos as usize] = bucket.next;
+            }
+            PrevPos::Chained(bucket_pos) => {
+                self.map.buckets[bucket_pos as usize].next = bucket.next;
+            }
+            _ => unreachable!(),
+        }
+
+        // and add it to the freelist
+        let free = self.map.free_head;
+        let bucket = &mut self.map.buckets[self.bucket_pos as usize];
+        let old_value = bucket.inner.take();
+        bucket.next = free;
+        self.map.free_head = self.bucket_pos;
+        self.map.buckets_in_use -= 1;
+
+        old_value.unwrap().1
+    }
+}
+
+/// An abstract view into a vacant entry within the map.
+pub struct VacantEntry<'a, 'b, K, V> {
+    /// Mutable reference to the map containing this entry.
+    pub(crate) map: RwLockWriteGuard<'b, CoreHashMap<'a, K, V>>,
+    /// The key to be inserted into this entry.
+    pub(crate) key: K,
+    /// The position within the dictionary corresponding to the key's hash.
+    pub(crate) dict_pos: u32,
+}
+
+impl<'b, K: Clone + Hash + Eq, V> VacantEntry<'_, 'b, K, V> {
+    /// Insert a value into the vacant entry, finding and populating an empty bucket in the process.
+    ///
+    /// # Errors
+    /// Will return [`FullError`] if there are no unoccupied buckets in the map.
+    pub fn insert(mut self, value: V) -> Result<ValueWriteGuard<'b, V>, FullError> {
+        let pos = self.map.alloc_bucket(self.key, value)?;
+        self.map.buckets[pos as usize].next = self.map.dictionary[self.dict_pos as usize];
+        self.map.dictionary[self.dict_pos as usize] = pos;
+
+        Ok(RwLockWriteGuard::map(self.map, |m| {
+            &mut m.buckets[pos as usize].inner.as_mut().unwrap().1
+        }))
+    }
+}

libs/neon-shmem/src/hash/tests.rs

@@ -0,0 +1,428 @@
+use std::collections::BTreeMap;
+use std::collections::HashSet;
+use std::fmt::Debug;
+use std::mem::MaybeUninit;
+
+use crate::hash::Entry;
+use crate::hash::HashMapAccess;
+use crate::hash::HashMapInit;
+use crate::hash::core::FullError;
+
+use rand::seq::SliceRandom;
+use rand::{Rng, RngCore};
+use rand_distr::Zipf;
+
+const TEST_KEY_LEN: usize = 16;
+
+#[derive(Clone, Copy, Debug, Hash, PartialEq, Eq, PartialOrd, Ord)]
+struct TestKey([u8; TEST_KEY_LEN]);
+
+impl From<&TestKey> for u128 {
+    fn from(val: &TestKey) -> u128 {
+        u128::from_be_bytes(val.0)
+    }
+}
+
+impl From<u128> for TestKey {
+    fn from(val: u128) -> TestKey {
+        TestKey(val.to_be_bytes())
+    }
+}
+
+impl<'a> From<&'a [u8]> for TestKey {
+    fn from(bytes: &'a [u8]) -> TestKey {
+        TestKey(bytes.try_into().unwrap())
+    }
+}
+
+fn test_inserts<K: Into<TestKey> + Copy>(keys: &[K]) {
+    let w = HashMapInit::<TestKey, usize>::new_resizeable_named(100000, 120000, "test_inserts")
+        .attach_writer();
+
+    for (idx, k) in keys.iter().enumerate() {
+        let res = w.entry((*k).into());
+        match res {
+            Entry::Occupied(mut e) => {
+                e.insert(idx);
+            }
+            Entry::Vacant(e) => {
+                let res = e.insert(idx);
+                assert!(res.is_ok());
+            }
+        };
+    }
+
+    for (idx, k) in keys.iter().enumerate() {
+        let x = w.get(&(*k).into());
+        let value = x.as_deref().copied();
+        assert_eq!(value, Some(idx));
+    }
+}
+
+#[test]
+fn dense() {
+    // This exercises splitting a node with prefix
+    let keys: &[u128] = &[0, 1, 2, 3, 256];
+    test_inserts(keys);
+
+    // Dense keys
+    let mut keys: Vec<u128> = (0..10000).collect();
+    test_inserts(&keys);
+
+    // Do the same in random orders
+    for _ in 1..10 {
+        keys.shuffle(&mut rand::rng());
+        test_inserts(&keys);
+    }
+}
+
+#[test]
+fn sparse() {
+    // sparse keys
+    let mut keys: Vec<TestKey> = Vec::new();
+    let mut used_keys = HashSet::new();
+    for _ in 0..10000 {
+        loop {
+            let key = rand::random::<u128>();
+            if used_keys.contains(&key) {
+                continue;
+            }
+            used_keys.insert(key);
+            keys.push(key.into());
+            break;
+        }
+    }
+    test_inserts(&keys);
+}
+
+#[derive(Clone, Debug)]
+struct TestOp(TestKey, Option<usize>);
+
+fn apply_op(
+    op: &TestOp,
+    map: &mut HashMapAccess<TestKey, usize>,
+    shadow: &mut BTreeMap<TestKey, usize>,
+) {
+    // apply the change to the shadow tree first
+    let shadow_existing = if let Some(v) = op.1 {
+        shadow.insert(op.0, v)
+    } else {
+        shadow.remove(&op.0)
+    };
+
+    let entry = map.entry(op.0);
+    let hash_existing = match op.1 {
+        Some(new) => match entry {
+            Entry::Occupied(mut e) => Some(e.insert(new)),
+            Entry::Vacant(e) => {
+                _ = e.insert(new).unwrap();
+                None
+            }
+        },
+        None => match entry {
+            Entry::Occupied(e) => Some(e.remove()),
+            Entry::Vacant(_) => None,
+        },
+    };
+
+    assert_eq!(shadow_existing, hash_existing);
+}
+
+fn do_random_ops(
+    num_ops: usize,
+    size: u32,
+    del_prob: f64,
+    writer: &mut HashMapAccess<TestKey, usize>,
+    shadow: &mut BTreeMap<TestKey, usize>,
+    rng: &mut rand::rngs::ThreadRng,
+) {
+    for i in 0..num_ops {
+        let key: TestKey = ((rng.next_u32() % size) as u128).into();
+        let op = TestOp(
+            key,
+            if rng.random_bool(del_prob) {
+                Some(i)
+            } else {
+                None
+            },
+        );
+        apply_op(&op, writer, shadow);
+    }
+}
+
+fn do_deletes(
+    num_ops: usize,
+    writer: &mut HashMapAccess<TestKey, usize>,
+    shadow: &mut BTreeMap<TestKey, usize>,
+) {
+    for _ in 0..num_ops {
+        let (k, _) = shadow.pop_first().unwrap();
+        writer.remove(&k);
+    }
+}
+
+fn do_shrink(
+    writer: &mut HashMapAccess<TestKey, usize>,
+    shadow: &mut BTreeMap<TestKey, usize>,
+    from: u32,
+    to: u32,
+) {
+    assert!(writer.shrink_goal().is_none());
+    writer.begin_shrink(to);
+    assert_eq!(writer.shrink_goal(), Some(to as usize));
+    for i in to..from {
+        if let Some(entry) = writer.entry_at_bucket(i as usize) {
+            shadow.remove(&entry._key);
+            entry.remove();
+        }
+    }
+    let old_usage = writer.get_num_buckets_in_use();
+    writer.finish_shrink().unwrap();
+    assert!(writer.shrink_goal().is_none());
+    assert_eq!(writer.get_num_buckets_in_use(), old_usage);
+}
+
+#[test]
+fn random_ops() {
+    let mut writer =
+        HashMapInit::<TestKey, usize>::new_resizeable_named(100000, 120000, "test_random")
+            .attach_writer();
+    let mut shadow: std::collections::BTreeMap<TestKey, usize> = BTreeMap::new();
+
+    let distribution = Zipf::new(u128::MAX as f64, 1.1).unwrap();
+    let mut rng = rand::rng();
+    for i in 0..100000 {
+        let key: TestKey = (rng.sample(distribution) as u128).into();
+
+        let op = TestOp(key, if rng.random_bool(0.75) { Some(i) } else { None });
+
+        apply_op(&op, &mut writer, &mut shadow);
+    }
+}
+
+#[test]
+fn test_shuffle() {
+    let mut writer = HashMapInit::<TestKey, usize>::new_resizeable_named(1000, 1200, "test_shuf")
+        .attach_writer();
+    let mut shadow: std::collections::BTreeMap<TestKey, usize> = BTreeMap::new();
+    let mut rng = rand::rng();
+
+    do_random_ops(10000, 1000, 0.75, &mut writer, &mut shadow, &mut rng);
+    writer.shuffle();
+    do_random_ops(10000, 1000, 0.75, &mut writer, &mut shadow, &mut rng);
+}
+
+#[test]
+fn test_grow() {
+    let mut writer = HashMapInit::<TestKey, usize>::new_resizeable_named(1000, 2000, "test_grow")
+        .attach_writer();
+    let mut shadow: std::collections::BTreeMap<TestKey, usize> = BTreeMap::new();
+    let mut rng = rand::rng();
+
+    do_random_ops(10000, 1000, 0.75, &mut writer, &mut shadow, &mut rng);
+    let old_usage = writer.get_num_buckets_in_use();
+    writer.grow(1500).unwrap();
+    assert_eq!(writer.get_num_buckets_in_use(), old_usage);
+    assert_eq!(writer.get_num_buckets(), 1500);
+    do_random_ops(10000, 1500, 0.75, &mut writer, &mut shadow, &mut rng);
+}
+
+#[test]
+fn test_clear() {
+    let mut writer = HashMapInit::<TestKey, usize>::new_resizeable_named(1500, 2000, "test_clear")
+        .attach_writer();
+    let mut shadow: std::collections::BTreeMap<TestKey, usize> = BTreeMap::new();
+    let mut rng = rand::rng();
+    do_random_ops(2000, 1500, 0.75, &mut writer, &mut shadow, &mut rng);
+    writer.clear();
+    assert_eq!(writer.get_num_buckets_in_use(), 0);
+    assert_eq!(writer.get_num_buckets(), 1500);
+    while let Some((key, _)) = shadow.pop_first() {
+        assert!(writer.get(&key).is_none());
+    }
+    do_random_ops(2000, 1500, 0.75, &mut writer, &mut shadow, &mut rng);
+    for i in 0..(1500 - writer.get_num_buckets_in_use()) {
+        writer.insert((1500 + i as u128).into(), 0).unwrap();
+    }
+    assert_eq!(writer.insert(5000.into(), 0), Err(FullError {}));
+    writer.clear();
+    assert!(writer.insert(5000.into(), 0).is_ok());
+}
+
+#[test]
+fn test_idx_remove() {
+    let mut writer = HashMapInit::<TestKey, usize>::new_resizeable_named(1500, 2000, "test_clear")
+        .attach_writer();
+    let mut shadow: std::collections::BTreeMap<TestKey, usize> = BTreeMap::new();
+    let mut rng = rand::rng();
+    do_random_ops(2000, 1500, 0.25, &mut writer, &mut shadow, &mut rng);
+    for _ in 0..100 {
+        let idx = (rng.next_u32() % 1500) as usize;
+        if let Some(e) = writer.entry_at_bucket(idx) {
+            shadow.remove(&e._key);
+            e.remove();
+        }
+    }
+    while let Some((key, val)) = shadow.pop_first() {
+        assert_eq!(*writer.get(&key).unwrap(), val);
+    }
+}
+
+#[test]
+fn test_idx_get() {
+    let mut writer = HashMapInit::<TestKey, usize>::new_resizeable_named(1500, 2000, "test_clear")
+        .attach_writer();
+    let mut shadow: std::collections::BTreeMap<TestKey, usize> = BTreeMap::new();
+    let mut rng = rand::rng();
+    do_random_ops(2000, 1500, 0.25, &mut writer, &mut shadow, &mut rng);
+    for _ in 0..100 {
+        let idx = (rng.next_u32() % 1500) as usize;
+        if let Some(pair) = writer.get_at_bucket(idx) {
+            {
+                let v: *const usize = &pair.1;
+                assert_eq!(writer.get_bucket_for_value(v), idx);
+            }
+            {
+                let v: *const usize = &pair.1;
+                assert_eq!(writer.get_bucket_for_value(v), idx);
+            }
+        }
+    }
+}
+
+#[test]
+fn test_shrink() {
+    let mut writer = HashMapInit::<TestKey, usize>::new_resizeable_named(1500, 2000, "test_shrink")
+        .attach_writer();
+    let mut shadow: std::collections::BTreeMap<TestKey, usize> = BTreeMap::new();
+    let mut rng = rand::rng();
+
+    do_random_ops(10000, 1500, 0.75, &mut writer, &mut shadow, &mut rng);
+    do_shrink(&mut writer, &mut shadow, 1500, 1000);
+    assert_eq!(writer.get_num_buckets(), 1000);
+    do_deletes(500, &mut writer, &mut shadow);
+    do_random_ops(10000, 500, 0.75, &mut writer, &mut shadow, &mut rng);
+    assert!(writer.get_num_buckets_in_use() <= 1000);
+}
+
+#[test]
+fn test_shrink_grow_seq() {
+    let mut writer =
+        HashMapInit::<TestKey, usize>::new_resizeable_named(1000, 20000, "test_grow_seq")
+            .attach_writer();
+    let mut shadow: std::collections::BTreeMap<TestKey, usize> = BTreeMap::new();
+    let mut rng = rand::rng();
+
+    do_random_ops(500, 1000, 0.1, &mut writer, &mut shadow, &mut rng);
+    eprintln!("Shrinking to 750");
+    do_shrink(&mut writer, &mut shadow, 1000, 750);
+    do_random_ops(200, 1000, 0.5, &mut writer, &mut shadow, &mut rng);
+    eprintln!("Growing to 1500");
+    writer.grow(1500).unwrap();
+    do_random_ops(600, 1500, 0.1, &mut writer, &mut shadow, &mut rng);
+    eprintln!("Shrinking to 200");
+    while shadow.len() > 100 {
+        do_deletes(1, &mut writer, &mut shadow);
+    }
+    do_shrink(&mut writer, &mut shadow, 1500, 200);
+    do_random_ops(50, 1500, 0.25, &mut writer, &mut shadow, &mut rng);
+    eprintln!("Growing to 10k");
+    writer.grow(10000).unwrap();
+    do_random_ops(10000, 5000, 0.25, &mut writer, &mut shadow, &mut rng);
+}
+
+#[test]
+fn test_bucket_ops() {
+    let writer = HashMapInit::<TestKey, usize>::new_resizeable_named(1000, 1200, "test_bucket_ops")
+        .attach_writer();
+    match writer.entry(1.into()) {
+        Entry::Occupied(mut e) => {
+            e.insert(2);
+        }
+        Entry::Vacant(e) => {
+            _ = e.insert(2).unwrap();
+        }
+    }
+    assert_eq!(writer.get_num_buckets_in_use(), 1);
+    assert_eq!(writer.get_num_buckets(), 1000);
+    assert_eq!(*writer.get(&1.into()).unwrap(), 2);
+    let pos = match writer.entry(1.into()) {
+        Entry::Occupied(e) => {
+            assert_eq!(e._key, 1.into());
+            e.bucket_pos as usize
+        }
+        Entry::Vacant(_) => {
+            panic!("Insert didn't affect entry");
+        }
+    };
+    assert_eq!(writer.entry_at_bucket(pos).unwrap()._key, 1.into());
+    assert_eq!(*writer.get_at_bucket(pos).unwrap(), (1.into(), 2));
+    {
+        let ptr: *const usize = &*writer.get(&1.into()).unwrap();
+        assert_eq!(writer.get_bucket_for_value(ptr), pos);
+    }
+    writer.remove(&1.into());
+    assert!(writer.get(&1.into()).is_none());
+}
+
+#[test]
+fn test_shrink_zero() {
+    let mut writer =
+        HashMapInit::<TestKey, usize>::new_resizeable_named(1500, 2000, "test_shrink_zero")
+            .attach_writer();
+    writer.begin_shrink(0);
+    for i in 0..1500 {
+        writer.entry_at_bucket(i).map(|x| x.remove());
+    }
+    writer.finish_shrink().unwrap();
+    assert_eq!(writer.get_num_buckets_in_use(), 0);
+    let entry = writer.entry(1.into());
+    if let Entry::Vacant(v) = entry {
+        assert!(v.insert(2).is_err());
+    } else {
+        panic!("Somehow got non-vacant entry in empty map.")
+    }
+    writer.grow(50).unwrap();
+    let entry = writer.entry(1.into());
+    if let Entry::Vacant(v) = entry {
+        assert!(v.insert(2).is_ok());
+    } else {
+        panic!("Somehow got non-vacant entry in empty map.")
+    }
+    assert_eq!(writer.get_num_buckets_in_use(), 1);
+}
+
+#[test]
+#[should_panic]
+fn test_grow_oom() {
+    let writer = HashMapInit::<TestKey, usize>::new_resizeable_named(1500, 2000, "test_grow_oom")
+        .attach_writer();
+    writer.grow(20000).unwrap();
+}
+
+#[test]
+#[should_panic]
+fn test_shrink_bigger() {
+    let mut writer =
+        HashMapInit::<TestKey, usize>::new_resizeable_named(1500, 2500, "test_shrink_bigger")
+            .attach_writer();
+    writer.begin_shrink(2000);
+}
+
+#[test]
+#[should_panic]
+fn test_shrink_early_finish() {
+    let writer =
+        HashMapInit::<TestKey, usize>::new_resizeable_named(1500, 2500, "test_shrink_early_finish")
+            .attach_writer();
+    writer.finish_shrink().unwrap();
+}
+
+#[test]
+#[should_panic]
+fn test_shrink_fixed_size() {
+    let mut area = [MaybeUninit::uninit(); 10000];
+    let init_struct = HashMapInit::<TestKey, usize>::with_fixed(3, &mut area);
+    let mut writer = init_struct.attach_writer();
+    writer.begin_shrink(1);
+}

libs/neon-shmem/src/lib.rs

@@ -1,418 +1,3 @@
-//! Shared memory utilities for neon communicator
-
-use std::num::NonZeroUsize;
-use std::os::fd::{AsFd, BorrowedFd, OwnedFd};
-use std::ptr::NonNull;
-use std::sync::atomic::{AtomicUsize, Ordering};
-
-use nix::errno::Errno;
-use nix::sys::mman::MapFlags;
-use nix::sys::mman::ProtFlags;
-use nix::sys::mman::mmap as nix_mmap;
-use nix::sys::mman::munmap as nix_munmap;
-use nix::unistd::ftruncate as nix_ftruncate;
-
-/// ShmemHandle represents a shared memory area that can be shared by processes over fork().
-/// Unlike shared memory allocated by Postgres, this area is resizable, up to 'max_size' that's
-/// specified at creation.
-///
-/// The area is backed by an anonymous file created with memfd_create(). The full address space for
-/// 'max_size' is reserved up-front with mmap(), but whenever you call [`ShmemHandle::set_size`],
-/// the underlying file is resized. Do not access the area beyond the current size. Currently, that
-/// will cause the file to be expanded, but we might use mprotect() etc. to enforce that in the
-/// future.
-pub struct ShmemHandle {
-    /// memfd file descriptor
-    fd: OwnedFd,
-
-    max_size: usize,
-
-    // Pointer to the beginning of the shared memory area. The header is stored there.
-    shared_ptr: NonNull<SharedStruct>,
-
-    // Pointer to the beginning of the user data
-    pub data_ptr: NonNull<u8>,
-}
-
-/// This is stored at the beginning in the shared memory area.
-struct SharedStruct {
-    max_size: usize,
-
-    /// Current size of the backing file. The high-order bit is used for the RESIZE_IN_PROGRESS flag
-    current_size: AtomicUsize,
-}
-
-const RESIZE_IN_PROGRESS: usize = 1 << 63;
-
-const HEADER_SIZE: usize = std::mem::size_of::<SharedStruct>();
-
-/// Error type returned by the ShmemHandle functions.
-#[derive(thiserror::Error, Debug)]
-#[error("{msg}: {errno}")]
-pub struct Error {
-    pub msg: String,
-    pub errno: Errno,
-}
-
-impl Error {
-    fn new(msg: &str, errno: Errno) -> Error {
-        Error {
-            msg: msg.to_string(),
-            errno,
-        }
-    }
-}
-
-impl ShmemHandle {
-    /// Create a new shared memory area. To communicate between processes, the processes need to be
-    /// fork()'d after calling this, so that the ShmemHandle is inherited by all processes.
-    ///
-    /// If the ShmemHandle is dropped, the memory is unmapped from the current process. Other
-    /// processes can continue using it, however.
-    pub fn new(name: &str, initial_size: usize, max_size: usize) -> Result<ShmemHandle, Error> {
-        // create the backing anonymous file.
-        let fd = create_backing_file(name)?;
-
-        Self::new_with_fd(fd, initial_size, max_size)
-    }
-
-    fn new_with_fd(
-        fd: OwnedFd,
-        initial_size: usize,
-        max_size: usize,
-    ) -> Result<ShmemHandle, Error> {
-        // We reserve the high-order bit for the RESIZE_IN_PROGRESS flag, and the actual size
-        // is a little larger than this because of the SharedStruct header. Make the upper limit
-        // somewhat smaller than that, because with anything close to that, you'll run out of
-        // memory anyway.
-        if max_size >= 1 << 48 {
-            panic!("max size {max_size} too large");
-        }
-        if initial_size > max_size {
-            panic!("initial size {initial_size} larger than max size {max_size}");
-        }
-
-        // The actual initial / max size is the one given by the caller, plus the size of
-        // 'SharedStruct'.
-        let initial_size = HEADER_SIZE + initial_size;
-        let max_size = NonZeroUsize::new(HEADER_SIZE + max_size).unwrap();
-
-        // Reserve address space for it with mmap
-        //
-        // TODO: Use MAP_HUGETLB if possible
-        let start_ptr = unsafe {
-            nix_mmap(
-                None,
-                max_size,
-                ProtFlags::PROT_READ | ProtFlags::PROT_WRITE,
-                MapFlags::MAP_SHARED,
-                &fd,
-                0,
-            )
-        }
-        .map_err(|e| Error::new("mmap failed: {e}", e))?;
-
-        // Reserve space for the initial size
-        enlarge_file(fd.as_fd(), initial_size as u64)?;
-
-        // Initialize the header
-        let shared: NonNull<SharedStruct> = start_ptr.cast();
-        unsafe {
-            shared.write(SharedStruct {
-                max_size: max_size.into(),
-                current_size: AtomicUsize::new(initial_size),
-            })
-        };
-
-        // The user data begins after the header
-        let data_ptr = unsafe { start_ptr.cast().add(HEADER_SIZE) };
-
-        Ok(ShmemHandle {
-            fd,
-            max_size: max_size.into(),
-            shared_ptr: shared,
-            data_ptr,
-        })
-    }
-
-    // return reference to the header
-    fn shared(&self) -> &SharedStruct {
-        unsafe { self.shared_ptr.as_ref() }
-    }
-
-    /// Resize the shared memory area. 'new_size' must not be larger than the 'max_size' specified
-    /// when creating the area.
-    ///
-    /// This may only be called from one process/thread concurrently. We detect that case
-    /// and return an Error.
-    pub fn set_size(&self, new_size: usize) -> Result<(), Error> {
-        let new_size = new_size + HEADER_SIZE;
-        let shared = self.shared();
-
-        if new_size > self.max_size {
-            panic!(
-                "new size ({} is greater than max size ({})",
-                new_size, self.max_size
-            );
-        }
-        assert_eq!(self.max_size, shared.max_size);
-
-        // Lock the area by setting the bit in 'current_size'
-        //
-        // Ordering::Relaxed would probably be sufficient here, as we don't access any other memory
-        // and the posix_fallocate/ftruncate call is surely a synchronization point anyway. But
-        // since this is not performance-critical, better safe than sorry .
-        let mut old_size = shared.current_size.load(Ordering::Acquire);
-        loop {
-            if (old_size & RESIZE_IN_PROGRESS) != 0 {
-                return Err(Error::new(
-                    "concurrent resize detected",
-                    Errno::UnknownErrno,
-                ));
-            }
-            match shared.current_size.compare_exchange(
-                old_size,
-                new_size,
-                Ordering::Acquire,
-                Ordering::Relaxed,
-            ) {
-                Ok(_) => break,
-                Err(x) => old_size = x,
-            }
-        }
-
-        // Ok, we got the lock.
-        //
-        // NB: If anything goes wrong, we *must* clear the bit!
-        let result = {
-            use std::cmp::Ordering::{Equal, Greater, Less};
-            match new_size.cmp(&old_size) {
-                Less => nix_ftruncate(&self.fd, new_size as i64).map_err(|e| {
-                    Error::new("could not shrink shmem segment, ftruncate failed: {e}", e)
-                }),
-                Equal => Ok(()),
-                Greater => enlarge_file(self.fd.as_fd(), new_size as u64),
-            }
-        };
-
-        // Unlock
-        shared.current_size.store(
-            if result.is_ok() { new_size } else { old_size },
-            Ordering::Release,
-        );
-
-        result
-    }
-
-    /// Returns the current user-visible size of the shared memory segment.
-    ///
-    /// NOTE: a concurrent set_size() call can change the size at any time. It is the caller's
-    /// responsibility not to access the area beyond the current size.
-    pub fn current_size(&self) -> usize {
-        let total_current_size =
-            self.shared().current_size.load(Ordering::Relaxed) & !RESIZE_IN_PROGRESS;
-        total_current_size - HEADER_SIZE
-    }
-}
-
-impl Drop for ShmemHandle {
-    fn drop(&mut self) {
-        // SAFETY: The pointer was obtained from mmap() with the given size.
-        // We unmap the entire region.
-        let _ = unsafe { nix_munmap(self.shared_ptr.cast(), self.max_size) };
-        // The fd is dropped automatically by OwnedFd.
-    }
-}
-
-/// Create a "backing file" for the shared memory area. On Linux, use memfd_create(), to create an
-/// anonymous in-memory file. One macos, fall back to a regular file. That's good enough for
-/// development and testing, but in production we want the file to stay in memory.
-///
-/// disable 'unused_variables' warnings, because in the macos path, 'name' is unused.
-#[allow(unused_variables)]
-fn create_backing_file(name: &str) -> Result<OwnedFd, Error> {
-    #[cfg(not(target_os = "macos"))]
-    {
-        nix::sys::memfd::memfd_create(name, nix::sys::memfd::MFdFlags::empty())
-            .map_err(|e| Error::new("memfd_create failed: {e}", e))
-    }
-    #[cfg(target_os = "macos")]
-    {
-        let file = tempfile::tempfile().map_err(|e| {
-            Error::new(
-                "could not create temporary file to back shmem area: {e}",
-                nix::errno::Errno::from_raw(e.raw_os_error().unwrap_or(0)),
-            )
-        })?;
-        Ok(OwnedFd::from(file))
-    }
-}
-
-fn enlarge_file(fd: BorrowedFd, size: u64) -> Result<(), Error> {
-    // Use posix_fallocate() to enlarge the file. It reserves the space correctly, so that
-    // we don't get a segfault later when trying to actually use it.
-    #[cfg(not(target_os = "macos"))]
-    {
-        nix::fcntl::posix_fallocate(fd, 0, size as i64).map_err(|e| {
-            Error::new(
-                "could not grow shmem segment, posix_fallocate failed: {e}",
-                e,
-            )
-        })
-    }
-    // As a fallback on macos, which doesn't have posix_fallocate, use plain 'fallocate'
-    #[cfg(target_os = "macos")]
-    {
-        nix::unistd::ftruncate(fd, size as i64)
-            .map_err(|e| Error::new("could not grow shmem segment, ftruncate failed: {e}", e))
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    use nix::unistd::ForkResult;
-    use std::ops::Range;
-
-    /// check that all bytes in given range have the expected value.
-    fn assert_range(ptr: *const u8, expected: u8, range: Range<usize>) {
-        for i in range {
-            let b = unsafe { *(ptr.add(i)) };
-            assert_eq!(expected, b, "unexpected byte at offset {i}");
-        }
-    }
-
-    /// Write 'b' to all bytes in the given range
-    fn write_range(ptr: *mut u8, b: u8, range: Range<usize>) {
-        unsafe { std::ptr::write_bytes(ptr.add(range.start), b, range.end - range.start) };
-    }
-
-    // simple single-process test of growing and shrinking
-    #[test]
-    fn test_shmem_resize() -> Result<(), Error> {
-        let max_size = 1024 * 1024;
-        let init_struct = ShmemHandle::new("test_shmem_resize", 0, max_size)?;
-
-        assert_eq!(init_struct.current_size(), 0);
-
-        // Initial grow
-        let size1 = 10000;
-        init_struct.set_size(size1).unwrap();
-        assert_eq!(init_struct.current_size(), size1);
-
-        // Write some data
-        let data_ptr = init_struct.data_ptr.as_ptr();
-        write_range(data_ptr, 0xAA, 0..size1);
-        assert_range(data_ptr, 0xAA, 0..size1);
-
-        // Shrink
-        let size2 = 5000;
-        init_struct.set_size(size2).unwrap();
-        assert_eq!(init_struct.current_size(), size2);
-
-        // Grow again
-        let size3 = 20000;
-        init_struct.set_size(size3).unwrap();
-        assert_eq!(init_struct.current_size(), size3);
-
-        // Try to read it. The area that was shrunk and grown again should read as all zeros now
-        assert_range(data_ptr, 0xAA, 0..5000);
-        assert_range(data_ptr, 0, 5000..size1);
-
-        // Try to grow beyond max_size
-        //let size4 = max_size + 1;
-        //assert!(init_struct.set_size(size4).is_err());
-
-        // Dropping init_struct should unmap the memory
-        drop(init_struct);
-
-        Ok(())
-    }
-
-    /// This is used in tests to coordinate between test processes. It's like std::sync::Barrier,
-    /// but is stored in the shared memory area and works across processes. It's implemented by
-    /// polling, because e.g. standard rust mutexes are not guaranteed to work across processes.
-    struct SimpleBarrier {
-        num_procs: usize,
-        count: AtomicUsize,
-    }
-
-    impl SimpleBarrier {
-        unsafe fn init(ptr: *mut SimpleBarrier, num_procs: usize) {
-            unsafe {
-                *ptr = SimpleBarrier {
-                    num_procs,
-                    count: AtomicUsize::new(0),
-                }
-            }
-        }
-
-        pub fn wait(&self) {
-            let old = self.count.fetch_add(1, Ordering::Relaxed);
-
-            let generation = old / self.num_procs;
-
-            let mut current = old + 1;
-            while current < (generation + 1) * self.num_procs {
-                std::thread::sleep(std::time::Duration::from_millis(10));
-                current = self.count.load(Ordering::Relaxed);
-            }
-        }
-    }
-
-    #[test]
-    fn test_multi_process() {
-        // Initialize
-        let max_size = 1_000_000_000_000;
-        let init_struct = ShmemHandle::new("test_multi_process", 0, max_size).unwrap();
-        let ptr = init_struct.data_ptr.as_ptr();
-
-        // Store the SimpleBarrier in the first 1k of the area.
-        init_struct.set_size(10000).unwrap();
-        let barrier_ptr: *mut SimpleBarrier = unsafe {
-            ptr.add(ptr.align_offset(std::mem::align_of::<SimpleBarrier>()))
-                .cast()
-        };
-        unsafe { SimpleBarrier::init(barrier_ptr, 2) };
-        let barrier = unsafe { barrier_ptr.as_ref().unwrap() };
-
-        // Fork another test process. The code after this runs in both processes concurrently.
-        let fork_result = unsafe { nix::unistd::fork().unwrap() };
-
-        // In the parent, fill bytes between 1000..2000. In the child, between 2000..3000
-        if fork_result.is_parent() {
-            write_range(ptr, 0xAA, 1000..2000);
-        } else {
-            write_range(ptr, 0xBB, 2000..3000);
-        }
-        barrier.wait();
-        // Verify the contents. (in both processes)
-        assert_range(ptr, 0xAA, 1000..2000);
-        assert_range(ptr, 0xBB, 2000..3000);
-
-        // Grow, from the child this time
-        let size = 10_000_000;
-        if !fork_result.is_parent() {
-            init_struct.set_size(size).unwrap();
-        }
-        barrier.wait();
-
-        // make some writes at the end
-        if fork_result.is_parent() {
-            write_range(ptr, 0xAA, (size - 10)..size);
-        } else {
-            write_range(ptr, 0xBB, (size - 20)..(size - 10));
-        }
-        barrier.wait();
-
-        // Verify the contents. (This runs in both processes)
-        assert_range(ptr, 0, (size - 1000)..(size - 20));
-        assert_range(ptr, 0xBB, (size - 20)..(size - 10));
-        assert_range(ptr, 0xAA, (size - 10)..size);
-
-        if let ForkResult::Parent { child } = fork_result {
-            nix::sys::wait::waitpid(child, None).unwrap();
-        }
-    }
-}
+pub mod hash;
+pub mod shmem;
+pub mod sync;

libs/neon-shmem/src/shmem.rs

@@ -0,0 +1,409 @@
+//! Dynamically resizable contiguous chunk of shared memory
+
+use std::num::NonZeroUsize;
+use std::os::fd::{AsFd, BorrowedFd, OwnedFd};
+use std::ptr::NonNull;
+use std::sync::atomic::{AtomicUsize, Ordering};
+
+use nix::errno::Errno;
+use nix::sys::mman::MapFlags;
+use nix::sys::mman::ProtFlags;
+use nix::sys::mman::mmap as nix_mmap;
+use nix::sys::mman::munmap as nix_munmap;
+use nix::unistd::ftruncate as nix_ftruncate;
+
+/// `ShmemHandle` represents a shared memory area that can be shared by processes over `fork()`.
+/// Unlike shared memory allocated by Postgres, this area is resizable, up to `max_size` that's
+/// specified at creation.
+///
+/// The area is backed by an anonymous file created with `memfd_create()`. The full address space for
+/// `max_size` is reserved up-front with `mmap()`, but whenever you call [`ShmemHandle::set_size`],
+/// the underlying file is resized. Do not access the area beyond the current size. Currently, that
+/// will cause the file to be expanded, but we might use `mprotect()` etc. to enforce that in the
+/// future.
+pub struct ShmemHandle {
+    /// memfd file descriptor
+    fd: OwnedFd,
+
+    max_size: usize,
+
+    // Pointer to the beginning of the shared memory area. The header is stored there.
+    shared_ptr: NonNull<SharedStruct>,
+
+    // Pointer to the beginning of the user data
+    pub data_ptr: NonNull<u8>,
+}
+
+/// This is stored at the beginning in the shared memory area.
+struct SharedStruct {
+    max_size: usize,
+
+    /// Current size of the backing file. The high-order bit is used for the [`RESIZE_IN_PROGRESS`] flag.
+    current_size: AtomicUsize,
+}
+
+const RESIZE_IN_PROGRESS: usize = 1 << 63;
+
+const HEADER_SIZE: usize = std::mem::size_of::<SharedStruct>();
+
+/// Error type returned by the [`ShmemHandle`] functions.
+#[derive(thiserror::Error, Debug)]
+#[error("{msg}: {errno}")]
+pub struct Error {
+    pub msg: String,
+    pub errno: Errno,
+}
+
+impl Error {
+    fn new(msg: &str, errno: Errno) -> Self {
+        Self {
+            msg: msg.to_string(),
+            errno,
+        }
+    }
+}
+
+impl ShmemHandle {
+    /// Create a new shared memory area. To communicate between processes, the processes need to be
+    /// `fork()`'d after calling this, so that the `ShmemHandle` is inherited by all processes.
+    ///
+    /// If the `ShmemHandle` is dropped, the memory is unmapped from the current process. Other
+    /// processes can continue using it, however.
+    pub fn new(name: &str, initial_size: usize, max_size: usize) -> Result<Self, Error> {
+        // create the backing anonymous file.
+        let fd = create_backing_file(name)?;
+
+        Self::new_with_fd(fd, initial_size, max_size)
+    }
+
+    fn new_with_fd(fd: OwnedFd, initial_size: usize, max_size: usize) -> Result<Self, Error> {
+        // We reserve the high-order bit for the `RESIZE_IN_PROGRESS` flag, and the actual size
+        // is a little larger than this because of the SharedStruct header. Make the upper limit
+        // somewhat smaller than that, because with anything close to that, you'll run out of
+        // memory anyway.
+        assert!(max_size < 1 << 48, "max size {max_size} too large");
+
+        assert!(
+            initial_size <= max_size,
+            "initial size {initial_size} larger than max size {max_size}"
+        );
+
+        // The actual initial / max size is the one given by the caller, plus the size of
+        // 'SharedStruct'.
+        let initial_size = HEADER_SIZE + initial_size;
+        let max_size = NonZeroUsize::new(HEADER_SIZE + max_size).unwrap();
+
+        // Reserve address space for it with mmap
+        //
+        // TODO: Use MAP_HUGETLB if possible
+        let start_ptr = unsafe {
+            nix_mmap(
+                None,
+                max_size,
+                ProtFlags::PROT_READ | ProtFlags::PROT_WRITE,
+                MapFlags::MAP_SHARED,
+                &fd,
+                0,
+            )
+        }
+        .map_err(|e| Error::new("mmap failed", e))?;
+
+        // Reserve space for the initial size
+        enlarge_file(fd.as_fd(), initial_size as u64)?;
+
+        // Initialize the header
+        let shared: NonNull<SharedStruct> = start_ptr.cast();
+        unsafe {
+            shared.write(SharedStruct {
+                max_size: max_size.into(),
+                current_size: AtomicUsize::new(initial_size),
+            });
+        }
+
+        // The user data begins after the header
+        let data_ptr = unsafe { start_ptr.cast().add(HEADER_SIZE) };
+
+        Ok(Self {
+            fd,
+            max_size: max_size.into(),
+            shared_ptr: shared,
+            data_ptr,
+        })
+    }
+
+    // return reference to the header
+    fn shared(&self) -> &SharedStruct {
+        unsafe { self.shared_ptr.as_ref() }
+    }
+
+    /// Resize the shared memory area. `new_size` must not be larger than the `max_size` specified
+    /// when creating the area.
+    ///
+    /// This may only be called from one process/thread concurrently. We detect that case
+    /// and return an [`shmem::Error`](Error).
+    pub fn set_size(&self, new_size: usize) -> Result<(), Error> {
+        let new_size = new_size + HEADER_SIZE;
+        let shared = self.shared();
+
+        assert!(
+            new_size <= self.max_size,
+            "new size ({new_size}) is greater than max size ({})",
+            self.max_size
+        );
+
+        assert_eq!(self.max_size, shared.max_size);
+
+        // Lock the area by setting the bit in `current_size`
+        //
+        // Ordering::Relaxed would probably be sufficient here, as we don't access any other memory
+        // and the `posix_fallocate`/`ftruncate` call is surely a synchronization point anyway. But
+        // since this is not performance-critical, better safe than sorry.
+        let mut old_size = shared.current_size.load(Ordering::Acquire);
+        loop {
+            if (old_size & RESIZE_IN_PROGRESS) != 0 {
+                return Err(Error::new(
+                    "concurrent resize detected",
+                    Errno::UnknownErrno,
+                ));
+            }
+            match shared.current_size.compare_exchange(
+                old_size,
+                new_size,
+                Ordering::Acquire,
+                Ordering::Relaxed,
+            ) {
+                Ok(_) => break,
+                Err(x) => old_size = x,
+            }
+        }
+
+        // Ok, we got the lock.
+        //
+        // NB: If anything goes wrong, we *must* clear the bit!
+        let result = {
+            use std::cmp::Ordering::{Equal, Greater, Less};
+            match new_size.cmp(&old_size) {
+                Less => nix_ftruncate(&self.fd, new_size as i64)
+                    .map_err(|e| Error::new("could not shrink shmem segment, ftruncate failed", e)),
+                Equal => Ok(()),
+                Greater => enlarge_file(self.fd.as_fd(), new_size as u64),
+            }
+        };
+
+        // Unlock
+        shared.current_size.store(
+            if result.is_ok() { new_size } else { old_size },
+            Ordering::Release,
+        );
+
+        result
+    }
+
+    /// Returns the current user-visible size of the shared memory segment.
+    ///
+    /// NOTE: a concurrent [`ShmemHandle::set_size()`] call can change the size at any time.
+    /// It is the caller's responsibility not to access the area beyond the current size.
+    pub fn current_size(&self) -> usize {
+        let total_current_size =
+            self.shared().current_size.load(Ordering::Relaxed) & !RESIZE_IN_PROGRESS;
+        total_current_size - HEADER_SIZE
+    }
+}
+
+impl Drop for ShmemHandle {
+    fn drop(&mut self) {
+        // SAFETY: The pointer was obtained from mmap() with the given size.
+        // We unmap the entire region.
+        let _ = unsafe { nix_munmap(self.shared_ptr.cast(), self.max_size) };
+        // The fd is dropped automatically by OwnedFd.
+    }
+}
+
+/// Create a "backing file" for the shared memory area. On Linux, use `memfd_create()`, to create an
+/// anonymous in-memory file. One macos, fall back to a regular file. That's good enough for
+/// development and testing, but in production we want the file to stay in memory.
+///
+/// Disable unused variables warnings because `name` is unused in the macos path.
+#[allow(unused_variables)]
+fn create_backing_file(name: &str) -> Result<OwnedFd, Error> {
+    #[cfg(not(target_os = "macos"))]
+    {
+        nix::sys::memfd::memfd_create(name, nix::sys::memfd::MFdFlags::empty())
+            .map_err(|e| Error::new("memfd_create failed", e))
+    }
+    #[cfg(target_os = "macos")]
+    {
+        let file = tempfile::tempfile().map_err(|e| {
+            Error::new(
+                "could not create temporary file to back shmem area",
+                nix::errno::Errno::from_raw(e.raw_os_error().unwrap_or(0)),
+            )
+        })?;
+        Ok(OwnedFd::from(file))
+    }
+}
+
+fn enlarge_file(fd: BorrowedFd, size: u64) -> Result<(), Error> {
+    // Use posix_fallocate() to enlarge the file. It reserves the space correctly, so that
+    // we don't get a segfault later when trying to actually use it.
+    #[cfg(not(target_os = "macos"))]
+    {
+        nix::fcntl::posix_fallocate(fd, 0, size as i64)
+            .map_err(|e| Error::new("could not grow shmem segment, posix_fallocate failed", e))
+    }
+    // As a fallback on macos, which doesn't have posix_fallocate, use plain 'fallocate'
+    #[cfg(target_os = "macos")]
+    {
+        nix::unistd::ftruncate(fd, size as i64)
+            .map_err(|e| Error::new("could not grow shmem segment, ftruncate failed", e))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    use nix::unistd::ForkResult;
+    use std::ops::Range;
+
+    /// check that all bytes in given range have the expected value.
+    fn assert_range(ptr: *const u8, expected: u8, range: Range<usize>) {
+        for i in range {
+            let b = unsafe { *(ptr.add(i)) };
+            assert_eq!(expected, b, "unexpected byte at offset {i}");
+        }
+    }
+
+    /// Write 'b' to all bytes in the given range
+    fn write_range(ptr: *mut u8, b: u8, range: Range<usize>) {
+        unsafe { std::ptr::write_bytes(ptr.add(range.start), b, range.end - range.start) };
+    }
+
+    // simple single-process test of growing and shrinking
+    #[test]
+    fn test_shmem_resize() -> Result<(), Error> {
+        let max_size = 1024 * 1024;
+        let init_struct = ShmemHandle::new("test_shmem_resize", 0, max_size)?;
+
+        assert_eq!(init_struct.current_size(), 0);
+
+        // Initial grow
+        let size1 = 10000;
+        init_struct.set_size(size1).unwrap();
+        assert_eq!(init_struct.current_size(), size1);
+
+        // Write some data
+        let data_ptr = init_struct.data_ptr.as_ptr();
+        write_range(data_ptr, 0xAA, 0..size1);
+        assert_range(data_ptr, 0xAA, 0..size1);
+
+        // Shrink
+        let size2 = 5000;
+        init_struct.set_size(size2).unwrap();
+        assert_eq!(init_struct.current_size(), size2);
+
+        // Grow again
+        let size3 = 20000;
+        init_struct.set_size(size3).unwrap();
+        assert_eq!(init_struct.current_size(), size3);
+
+        // Try to read it. The area that was shrunk and grown again should read as all zeros now
+        assert_range(data_ptr, 0xAA, 0..5000);
+        assert_range(data_ptr, 0, 5000..size1);
+
+        // Try to grow beyond max_size
+        //let size4 = max_size + 1;
+        //assert!(init_struct.set_size(size4).is_err());
+
+        // Dropping init_struct should unmap the memory
+        drop(init_struct);
+
+        Ok(())
+    }
+
+    /// This is used in tests to coordinate between test processes. It's like `std::sync::Barrier`,
+    /// but is stored in the shared memory area and works across processes. It's implemented by
+    /// polling, because e.g. standard rust mutexes are not guaranteed to work across processes.
+    struct SimpleBarrier {
+        num_procs: usize,
+        count: AtomicUsize,
+    }
+
+    impl SimpleBarrier {
+        unsafe fn init(ptr: *mut SimpleBarrier, num_procs: usize) {
+            unsafe {
+                *ptr = SimpleBarrier {
+                    num_procs,
+                    count: AtomicUsize::new(0),
+                }
+            }
+        }
+
+        pub fn wait(&self) {
+            let old = self.count.fetch_add(1, Ordering::Relaxed);
+
+            let generation = old / self.num_procs;
+
+            let mut current = old + 1;
+            while current < (generation + 1) * self.num_procs {
+                std::thread::sleep(std::time::Duration::from_millis(10));
+                current = self.count.load(Ordering::Relaxed);
+            }
+        }
+    }
+
+    #[test]
+    fn test_multi_process() {
+        // Initialize
+        let max_size = 1_000_000_000_000;
+        let init_struct = ShmemHandle::new("test_multi_process", 0, max_size).unwrap();
+        let ptr = init_struct.data_ptr.as_ptr();
+
+        // Store the SimpleBarrier in the first 1k of the area.
+        init_struct.set_size(10000).unwrap();
+        let barrier_ptr: *mut SimpleBarrier = unsafe {
+            ptr.add(ptr.align_offset(std::mem::align_of::<SimpleBarrier>()))
+                .cast()
+        };
+        unsafe { SimpleBarrier::init(barrier_ptr, 2) };
+        let barrier = unsafe { barrier_ptr.as_ref().unwrap() };
+
+        // Fork another test process. The code after this runs in both processes concurrently.
+        let fork_result = unsafe { nix::unistd::fork().unwrap() };
+
+        // In the parent, fill bytes between 1000..2000. In the child, between 2000..3000
+        if fork_result.is_parent() {
+            write_range(ptr, 0xAA, 1000..2000);
+        } else {
+            write_range(ptr, 0xBB, 2000..3000);
+        }
+        barrier.wait();
+        // Verify the contents. (in both processes)
+        assert_range(ptr, 0xAA, 1000..2000);
+        assert_range(ptr, 0xBB, 2000..3000);
+
+        // Grow, from the child this time
+        let size = 10_000_000;
+        if !fork_result.is_parent() {
+            init_struct.set_size(size).unwrap();
+        }
+        barrier.wait();
+
+        // make some writes at the end
+        if fork_result.is_parent() {
+            write_range(ptr, 0xAA, (size - 10)..size);
+        } else {
+            write_range(ptr, 0xBB, (size - 20)..(size - 10));
+        }
+        barrier.wait();
+
+        // Verify the contents. (This runs in both processes)
+        assert_range(ptr, 0, (size - 1000)..(size - 20));
+        assert_range(ptr, 0xBB, (size - 20)..(size - 10));
+        assert_range(ptr, 0xAA, (size - 10)..size);
+
+        if let ForkResult::Parent { child } = fork_result {
+            nix::sys::wait::waitpid(child, None).unwrap();
+        }
+    }
+}

libs/neon-shmem/src/sync.rs

@@ -0,0 +1,111 @@
+//! Simple utilities akin to what's in [`std::sync`] but designed to work with shared memory.
+
+use std::mem::MaybeUninit;
+use std::ptr::NonNull;
+
+use nix::errno::Errno;
+
+pub type RwLock<T> = lock_api::RwLock<PthreadRwLock, T>;
+pub type RwLockReadGuard<'a, T> = lock_api::RwLockReadGuard<'a, PthreadRwLock, T>;
+pub type RwLockWriteGuard<'a, T> = lock_api::RwLockWriteGuard<'a, PthreadRwLock, T>;
+pub type ValueReadGuard<'a, T> = lock_api::MappedRwLockReadGuard<'a, PthreadRwLock, T>;
+pub type ValueWriteGuard<'a, T> = lock_api::MappedRwLockWriteGuard<'a, PthreadRwLock, T>;
+
+/// Shared memory read-write lock.
+pub struct PthreadRwLock(Option<NonNull<libc::pthread_rwlock_t>>);
+
+/// Simple macro that calls a function in the libc namespace and panics if return value is nonzero.
+macro_rules! libc_checked {
+    ($fn_name:ident ( $($arg:expr),* )) => {{
+        let res = libc::$fn_name($($arg),*);
+        if res != 0 {
+            panic!("{} failed with {}", stringify!($fn_name), Errno::from_raw(res));
+        }
+    }};
+}
+
+impl PthreadRwLock {
+    /// Creates a new `PthreadRwLock` on top of a pointer to a pthread rwlock.
+    ///
+    /// # Safety
+    /// `lock` must be non-null. Every unsafe operation will panic in the event of an error.
+    pub unsafe fn new(lock: *mut libc::pthread_rwlock_t) -> Self {
+        unsafe {
+            let mut attrs = MaybeUninit::uninit();
+            libc_checked!(pthread_rwlockattr_init(attrs.as_mut_ptr()));
+            libc_checked!(pthread_rwlockattr_setpshared(
+                attrs.as_mut_ptr(),
+                libc::PTHREAD_PROCESS_SHARED
+            ));
+            libc_checked!(pthread_rwlock_init(lock, attrs.as_mut_ptr()));
+            // Safety: POSIX specifies that "any function affecting the attributes
+            // object (including destruction) shall not affect any previously
+            // initialized read-write locks".
+            libc_checked!(pthread_rwlockattr_destroy(attrs.as_mut_ptr()));
+            Self(Some(NonNull::new_unchecked(lock)))
+        }
+    }
+
+    fn inner(&self) -> NonNull<libc::pthread_rwlock_t> {
+        match self.0 {
+            None => {
+                panic!("PthreadRwLock constructed badly - something likely used RawRwLock::INIT")
+            }
+            Some(x) => x,
+        }
+    }
+}
+
+unsafe impl lock_api::RawRwLock for PthreadRwLock {
+    type GuardMarker = lock_api::GuardSend;
+    const INIT: Self = Self(None);
+
+    fn try_lock_shared(&self) -> bool {
+        unsafe {
+            let res = libc::pthread_rwlock_tryrdlock(self.inner().as_ptr());
+            match res {
+                0 => true,
+                libc::EAGAIN => false,
+                _ => panic!(
+                    "pthread_rwlock_tryrdlock failed with {}",
+                    Errno::from_raw(res)
+                ),
+            }
+        }
+    }
+
+    fn try_lock_exclusive(&self) -> bool {
+        unsafe {
+            let res = libc::pthread_rwlock_trywrlock(self.inner().as_ptr());
+            match res {
+                0 => true,
+                libc::EAGAIN => false,
+                _ => panic!("try_wrlock failed with {}", Errno::from_raw(res)),
+            }
+        }
+    }
+
+    fn lock_shared(&self) {
+        unsafe {
+            libc_checked!(pthread_rwlock_rdlock(self.inner().as_ptr()));
+        }
+    }
+
+    fn lock_exclusive(&self) {
+        unsafe {
+            libc_checked!(pthread_rwlock_wrlock(self.inner().as_ptr()));
+        }
+    }
+
+    unsafe fn unlock_exclusive(&self) {
+        unsafe {
+            libc_checked!(pthread_rwlock_unlock(self.inner().as_ptr()));
+        }
+    }
+
+    unsafe fn unlock_shared(&self) {
+        unsafe {
+            libc_checked!(pthread_rwlock_unlock(self.inner().as_ptr()));
+        }
+    }
+}

libs/postgres_backend/src/lib.rs

@@ -749,7 +749,18 @@ impl<IO: AsyncRead + AsyncWrite + Unpin> PostgresBackend<IO> {
                 trace!("got query {query_string:?}");
                 if let Err(e) = handler.process_query(self, query_string).await {
                     match e {
-                        QueryError::Shutdown => return Ok(ProcessMsgResult::Break),
+                        err @ QueryError::Shutdown => {
+                            // Notify postgres of the connection shutdown at the libpq
+                            // protocol level. This avoids postgres having to tell apart
+                            // from an idle connection and a stale one, which is bug prone.
+                            let shutdown_error = short_error(&err);
+                            self.write_message_noflush(&BeMessage::ErrorResponse(
+                                &shutdown_error,
+                                Some(err.pg_error_code()),
+                            ))?;
+
+                            return Ok(ProcessMsgResult::Break);
+                        }
                         QueryError::SimulatedConnectionError => {
                             return Err(QueryError::SimulatedConnectionError);
                         }

libs/postgres_ffi/build.rs

@@ -110,7 +110,6 @@ fn main() -> anyhow::Result<()> {
             .allowlist_type("XLogRecPtr")
             .allowlist_type("XLogSegNo")
             .allowlist_type("TimeLineID")
-            .allowlist_type("TimestampTz")
             .allowlist_type("MultiXactId")
             .allowlist_type("MultiXactOffset")
             .allowlist_type("MultiXactStatus")

libs/postgres_ffi/src/lib.rs

@@ -227,8 +227,7 @@ pub mod walrecord;
 // Export some widely used datatypes that are unlikely to change across Postgres versions
 pub use v14::bindings::{
     BlockNumber, CheckPoint, ControlFileData, MultiXactId, OffsetNumber, Oid, PageHeaderData,
-    RepOriginId, TimeLineID, TimestampTz, TransactionId, XLogRecPtr, XLogRecord, XLogSegNo, uint32,
-    uint64,
+    RepOriginId, TimeLineID, TransactionId, XLogRecPtr, XLogRecord, XLogSegNo, uint32, uint64,
 };
 // Likewise for these, although the assumption that these don't change is a little more iffy.
 pub use v14::bindings::{MultiXactOffset, MultiXactStatus};

libs/postgres_ffi/src/walrecord.rs

@@ -4,13 +4,14 @@
 //! TODO: Generate separate types for each supported PG version
 
 use bytes::{Buf, Bytes};
+use postgres_ffi_types::TimestampTz;
 use serde::{Deserialize, Serialize};
 use utils::bin_ser::DeserializeError;
 use utils::lsn::Lsn;
 
 use crate::{
     BLCKSZ, BlockNumber, MultiXactId, MultiXactOffset, MultiXactStatus, Oid, PgMajorVersion,
-    RepOriginId, TimestampTz, TransactionId, XLOG_SIZE_OF_XLOG_RECORD, XLogRecord, pg_constants,
+    RepOriginId, TransactionId, XLOG_SIZE_OF_XLOG_RECORD, XLogRecord, pg_constants,
 };
 
 #[repr(C)]
@@ -863,7 +864,8 @@ pub mod v17 {
         XlHeapDelete, XlHeapInsert, XlHeapLock, XlHeapMultiInsert, XlHeapUpdate, XlParameterChange,
         rm_neon,
     };
-    pub use crate::{TimeLineID, TimestampTz};
+    pub use crate::TimeLineID;
+    pub use postgres_ffi_types::TimestampTz;
 
     #[repr(C)]
     #[derive(Debug)]

libs/postgres_ffi/src/xlog_utils.rs

@@ -9,10 +9,11 @@
 
 use super::super::waldecoder::WalStreamDecoder;
 use super::bindings::{
-    CheckPoint, ControlFileData, DBState_DB_SHUTDOWNED, FullTransactionId, TimeLineID, TimestampTz,
+    CheckPoint, ControlFileData, DBState_DB_SHUTDOWNED, FullTransactionId, TimeLineID,
     XLogLongPageHeaderData, XLogPageHeaderData, XLogRecPtr, XLogRecord, XLogSegNo, XLOG_PAGE_MAGIC,
     MY_PGVERSION
 };
+use postgres_ffi_types::TimestampTz;
 use super::wal_generator::LogicalMessageGenerator;
 use crate::pg_constants;
 use crate::PG_TLI;

libs/postgres_ffi_types/src/lib.rs

@@ -11,3 +11,4 @@ pub mod forknum;
 
 pub type Oid = u32;
 pub type RepOriginId = u16;
+pub type TimestampTz = i64;

libs/safekeeper_api/Cargo.toml

@@ -9,7 +9,7 @@ anyhow.workspace = true
 const_format.workspace = true
 serde.workspace = true
 serde_json.workspace = true
-postgres_ffi.workspace = true
+postgres_ffi_types.workspace = true
 postgres_versioninfo.workspace = true
 pq_proto.workspace = true
 tokio.workspace = true

libs/safekeeper_api/src/models.rs

@@ -3,7 +3,7 @@
 use std::net::SocketAddr;
 
 use pageserver_api::shard::ShardIdentity;
-use postgres_ffi::TimestampTz;
+use postgres_ffi_types::TimestampTz;
 use postgres_versioninfo::PgVersionId;
 use serde::{Deserialize, Serialize};
 use tokio::time::Instant;

libs/utils/Cargo.toml

@@ -47,6 +47,7 @@ tracing-subscriber = { workspace = true, features = ["json", "registry"] }
 tracing-utils.workspace = true
 rand.workspace = true
 scopeguard.workspace = true
+uuid.workspace = true
 strum.workspace = true
 strum_macros.workspace = true
 walkdir.workspace = true

libs/utils/src/auth.rs

@@ -12,7 +12,8 @@ use jsonwebtoken::{
     Algorithm, DecodingKey, EncodingKey, Header, TokenData, Validation, decode, encode,
 };
 use pem::Pem;
-use serde::{Deserialize, Serialize, de::DeserializeOwned};
+use serde::{Deserialize, Deserializer, Serialize, de::DeserializeOwned};
+use uuid::Uuid;
 
 use crate::id::TenantId;
 
@@ -25,6 +26,11 @@ pub enum Scope {
     /// Provides access to all data for a specific tenant (specified in `struct Claims` below)
     // TODO: join these two?
     Tenant,
+    /// Provides access to all data for a specific tenant, but based on endpoint ID. This token scope
+    /// is only used by compute to fetch the spec for a specific endpoint. The spec contains a Tenant-scoped
+    /// token authorizing access to all data of a tenant, so the spec-fetch API requires a TenantEndpoint
+    /// scope token to ensure that untrusted compute nodes can't fetch spec for arbitrary endpoints.
+    TenantEndpoint,
     /// Provides blanket access to all tenants on the pageserver plus pageserver-wide APIs.
     /// Should only be used e.g. for status check/tenant creation/list.
     PageServerApi,
@@ -51,17 +57,43 @@ pub enum Scope {
     ControllerPeer,
 }
 
+fn deserialize_empty_string_as_none_uuid<'de, D>(deserializer: D) -> Result<Option<Uuid>, D::Error>
+where
+    D: Deserializer<'de>,
+{
+    let opt = Option::<String>::deserialize(deserializer)?;
+    match opt.as_deref() {
+        Some("") => Ok(None),
+        Some(s) => Uuid::parse_str(s)
+            .map(Some)
+            .map_err(serde::de::Error::custom),
+        None => Ok(None),
+    }
+}
+
 /// JWT payload. See docs/authentication.md for the format
 #[derive(Debug, Serialize, Deserialize, Clone, PartialEq)]
 pub struct Claims {
     #[serde(default)]
     pub tenant_id: Option<TenantId>,
+    #[serde(
+        default,
+        skip_serializing_if = "Option::is_none",
+        // Neon control plane includes this field as empty in the claims.
+        // Consider it None in those cases.
+        deserialize_with = "deserialize_empty_string_as_none_uuid"
+    )]
+    pub endpoint_id: Option<Uuid>,
     pub scope: Scope,
 }
 
 impl Claims {
     pub fn new(tenant_id: Option<TenantId>, scope: Scope) -> Self {
-        Self { tenant_id, scope }
+        Self {
+            tenant_id,
+            scope,
+            endpoint_id: None,
+        }
     }
 }
 
@@ -212,6 +244,7 @@ MC4CAQAwBQYDK2VwBCIEID/Drmc1AA6U/znNRWpF3zEGegOATQxfkdWxitcOMsIH
         let expected_claims = Claims {
             tenant_id: Some(TenantId::from_str("3d1f7595b468230304e0b73cecbcb081").unwrap()),
             scope: Scope::Tenant,
+            endpoint_id: None,
         };
 
         // A test token containing the following payload, signed using TEST_PRIV_KEY_ED25519:
@@ -240,6 +273,7 @@ MC4CAQAwBQYDK2VwBCIEID/Drmc1AA6U/znNRWpF3zEGegOATQxfkdWxitcOMsIH
         let claims = Claims {
             tenant_id: Some(TenantId::from_str("3d1f7595b468230304e0b73cecbcb081").unwrap()),
             scope: Scope::Tenant,
+            endpoint_id: None,
         };
 
         let pem = pem::parse(TEST_PRIV_KEY_ED25519).unwrap();

libs/wal_decoder/src/models/record.rs

@@ -2,7 +2,8 @@
 
 use bytes::Bytes;
 use postgres_ffi::walrecord::{MultiXactMember, describe_postgres_wal_record};
-use postgres_ffi::{MultiXactId, MultiXactOffset, TimestampTz, TransactionId};
+use postgres_ffi::{MultiXactId, MultiXactOffset, TransactionId};
+use postgres_ffi_types::TimestampTz;
 use serde::{Deserialize, Serialize};
 use utils::bin_ser::DeserializeError;
 

libs/walproposer/src/api_bindings.rs

@@ -431,7 +431,7 @@ pub fn empty_shmem() -> crate::bindings::WalproposerShmemState {
     let empty_wal_rate_limiter = crate::bindings::WalRateLimiter {
         should_limit: crate::bindings::pg_atomic_uint32 { value: 0 },
         sent_bytes: 0,
-        last_recorded_time_us: 0,
+        last_recorded_time_us: crate::bindings::pg_atomic_uint64 { value: 0 },
     };
 
     crate::bindings::WalproposerShmemState {

pageserver/client/src/mgmt_api.rs

@@ -873,6 +873,22 @@ impl Client {
             .map_err(Error::ReceiveBody)
     }
 
+    pub async fn reset_alert_gauges(&self) -> Result<()> {
+        let uri = format!(
+            "{}/hadron-internal/reset_alert_gauges",
+            self.mgmt_api_endpoint
+        );
+        self.start_request(Method::POST, uri)
+            .send()
+            .await
+            .map_err(Error::SendRequest)?
+            .error_from_body()
+            .await?
+            .json()
+            .await
+            .map_err(Error::ReceiveBody)
+    }
+
     pub async fn wait_lsn(
         &self,
         tenant_shard_id: TenantShardId,

pageserver/src/auth.rs

@@ -20,7 +20,8 @@ pub fn check_permission(claims: &Claims, tenant_id: Option<TenantId>) -> Result<
             | Scope::GenerationsApi
             | Scope::Infra
             | Scope::Scrubber
-            | Scope::ControllerPeer,
+            | Scope::ControllerPeer
+            | Scope::TenantEndpoint,
             _,
         ) => Err(AuthError(
             format!(

pageserver/src/deletion_queue/validator.rs

@@ -1,5 +1,5 @@
 //! The validator is responsible for validating DeletionLists for execution,
-//! based on whethe the generation in the DeletionList is still the latest
+//! based on whether the generation in the DeletionList is still the latest
 //! generation for a tenant.
 //!
 //! The purpose of validation is to ensure split-brain safety in the cluster

pageserver/src/http/routes.rs

@@ -2357,6 +2357,7 @@ async fn timeline_compact_handler(
         flags,
         sub_compaction,
         sub_compaction_max_job_size_mb,
+        gc_compaction_do_metadata_compaction: false,
     };
 
     let scheduled = compact_request

pageserver/src/pgdatadir_mapping.rs

@@ -25,9 +25,9 @@ use pageserver_api::keyspace::{KeySpaceRandomAccum, SparseKeySpace};
 use pageserver_api::models::RelSizeMigration;
 use pageserver_api::reltag::{BlockNumber, RelTag, SlruKind};
 use pageserver_api::shard::ShardIdentity;
-use postgres_ffi::{BLCKSZ, PgMajorVersion, TimestampTz, TransactionId};
+use postgres_ffi::{BLCKSZ, PgMajorVersion, TransactionId};
 use postgres_ffi_types::forknum::{FSM_FORKNUM, VISIBILITYMAP_FORKNUM};
-use postgres_ffi_types::{Oid, RepOriginId};
+use postgres_ffi_types::{Oid, RepOriginId, TimestampTz};
 use serde::{Deserialize, Serialize};
 use strum::IntoEnumIterator;
 use tokio_util::sync::CancellationToken;
@@ -813,6 +813,7 @@ impl Timeline {
         let gc_cutoff_lsn_guard = self.get_applied_gc_cutoff_lsn();
         let gc_cutoff_planned = {
             let gc_info = self.gc_info.read().unwrap();
+            info!(cutoffs=?gc_info.cutoffs, applied_cutoff=%*gc_cutoff_lsn_guard, "starting find_lsn_for_timestamp");
             gc_info.min_cutoff()
         };
         // Usually the planned cutoff is newer than the cutoff of the last gc run,

pageserver/src/tenant.rs

@@ -9216,7 +9216,11 @@ mod tests {
 
         let cancel = CancellationToken::new();
         tline
-            .compact_with_gc(&cancel, CompactOptions::default(), &ctx)
+            .compact_with_gc(
+                &cancel,
+                CompactOptions::default_for_gc_compaction_unit_tests(),
+                &ctx,
+            )
             .await
             .unwrap();
 
@@ -9299,7 +9303,11 @@ mod tests {
             guard.cutoffs.space = Lsn(0x40);
         }
         tline
-            .compact_with_gc(&cancel, CompactOptions::default(), &ctx)
+            .compact_with_gc(
+                &cancel,
+                CompactOptions::default_for_gc_compaction_unit_tests(),
+                &ctx,
+            )
             .await
             .unwrap();
 
@@ -9836,7 +9844,11 @@ mod tests {
 
         let cancel = CancellationToken::new();
         tline
-            .compact_with_gc(&cancel, CompactOptions::default(), &ctx)
+            .compact_with_gc(
+                &cancel,
+                CompactOptions::default_for_gc_compaction_unit_tests(),
+                &ctx,
+            )
             .await
             .unwrap();
 
@@ -9871,7 +9883,11 @@ mod tests {
             guard.cutoffs.space = Lsn(0x40);
         }
         tline
-            .compact_with_gc(&cancel, CompactOptions::default(), &ctx)
+            .compact_with_gc(
+                &cancel,
+                CompactOptions::default_for_gc_compaction_unit_tests(),
+                &ctx,
+            )
             .await
             .unwrap();
 
@@ -10446,7 +10462,7 @@ mod tests {
                 &cancel,
                 CompactOptions {
                     flags: dryrun_flags,
-                    ..Default::default()
+                    ..CompactOptions::default_for_gc_compaction_unit_tests()
                 },
                 &ctx,
             )
@@ -10457,14 +10473,22 @@ mod tests {
         verify_result().await;
 
         tline
-            .compact_with_gc(&cancel, CompactOptions::default(), &ctx)
+            .compact_with_gc(
+                &cancel,
+                CompactOptions::default_for_gc_compaction_unit_tests(),
+                &ctx,
+            )
             .await
             .unwrap();
         verify_result().await;
 
         // compact again
         tline
-            .compact_with_gc(&cancel, CompactOptions::default(), &ctx)
+            .compact_with_gc(
+                &cancel,
+                CompactOptions::default_for_gc_compaction_unit_tests(),
+                &ctx,
+            )
             .await
             .unwrap();
         verify_result().await;
@@ -10483,14 +10507,22 @@ mod tests {
             guard.cutoffs.space = Lsn(0x38);
         }
         tline
-            .compact_with_gc(&cancel, CompactOptions::default(), &ctx)
+            .compact_with_gc(
+                &cancel,
+                CompactOptions::default_for_gc_compaction_unit_tests(),
+                &ctx,
+            )
             .await
             .unwrap();
         verify_result().await; // no wals between 0x30 and 0x38, so we should obtain the same result
 
         // not increasing the GC horizon and compact again
         tline
-            .compact_with_gc(&cancel, CompactOptions::default(), &ctx)
+            .compact_with_gc(
+                &cancel,
+                CompactOptions::default_for_gc_compaction_unit_tests(),
+                &ctx,
+            )
             .await
             .unwrap();
         verify_result().await;
@@ -10695,7 +10727,7 @@ mod tests {
                 &cancel,
                 CompactOptions {
                     flags: dryrun_flags,
-                    ..Default::default()
+                    ..CompactOptions::default_for_gc_compaction_unit_tests()
                 },
                 &ctx,
             )
@@ -10706,14 +10738,22 @@ mod tests {
         verify_result().await;
 
         tline
-            .compact_with_gc(&cancel, CompactOptions::default(), &ctx)
+            .compact_with_gc(
+                &cancel,
+                CompactOptions::default_for_gc_compaction_unit_tests(),
+                &ctx,
+            )
             .await
             .unwrap();
         verify_result().await;
 
         // compact again
         tline
-            .compact_with_gc(&cancel, CompactOptions::default(), &ctx)
+            .compact_with_gc(
+                &cancel,
+                CompactOptions::default_for_gc_compaction_unit_tests(),
+                &ctx,
+            )
             .await
             .unwrap();
         verify_result().await;
@@ -10913,7 +10953,11 @@ mod tests {
 
         let cancel = CancellationToken::new();
         branch_tline
-            .compact_with_gc(&cancel, CompactOptions::default(), &ctx)
+            .compact_with_gc(
+                &cancel,
+                CompactOptions::default_for_gc_compaction_unit_tests(),
+                &ctx,
+            )
             .await
             .unwrap();
 
@@ -10926,7 +10970,7 @@ mod tests {
                 &cancel,
                 CompactOptions {
                     compact_lsn_range: Some(CompactLsnRange::above(Lsn(0x40))),
-                    ..Default::default()
+                    ..CompactOptions::default_for_gc_compaction_unit_tests()
                 },
                 &ctx,
             )
@@ -11594,7 +11638,7 @@ mod tests {
                 CompactOptions {
                     flags: EnumSet::new(),
                     compact_key_range: Some((get_key(0)..get_key(2)).into()),
-                    ..Default::default()
+                    ..CompactOptions::default_for_gc_compaction_unit_tests()
                 },
                 &ctx,
             )
@@ -11641,7 +11685,7 @@ mod tests {
                 CompactOptions {
                     flags: EnumSet::new(),
                     compact_key_range: Some((get_key(2)..get_key(4)).into()),
-                    ..Default::default()
+                    ..CompactOptions::default_for_gc_compaction_unit_tests()
                 },
                 &ctx,
             )
@@ -11693,7 +11737,7 @@ mod tests {
                 CompactOptions {
                     flags: EnumSet::new(),
                     compact_key_range: Some((get_key(4)..get_key(9)).into()),
-                    ..Default::default()
+                    ..CompactOptions::default_for_gc_compaction_unit_tests()
                 },
                 &ctx,
             )
@@ -11744,7 +11788,7 @@ mod tests {
                 CompactOptions {
                     flags: EnumSet::new(),
                     compact_key_range: Some((get_key(9)..get_key(10)).into()),
-                    ..Default::default()
+                    ..CompactOptions::default_for_gc_compaction_unit_tests()
                 },
                 &ctx,
             )
@@ -11800,7 +11844,7 @@ mod tests {
                 CompactOptions {
                     flags: EnumSet::new(),
                     compact_key_range: Some((get_key(0)..get_key(10)).into()),
-                    ..Default::default()
+                    ..CompactOptions::default_for_gc_compaction_unit_tests()
                 },
                 &ctx,
             )
@@ -12071,7 +12115,7 @@ mod tests {
                 &cancel,
                 CompactOptions {
                     compact_lsn_range: Some(CompactLsnRange::above(Lsn(0x28))),
-                    ..Default::default()
+                    ..CompactOptions::default_for_gc_compaction_unit_tests()
                 },
                 &ctx,
             )
@@ -12106,7 +12150,11 @@ mod tests {
 
         // compact again
         tline
-            .compact_with_gc(&cancel, CompactOptions::default(), &ctx)
+            .compact_with_gc(
+                &cancel,
+                CompactOptions::default_for_gc_compaction_unit_tests(),
+                &ctx,
+            )
             .await
             .unwrap();
         verify_result().await;
@@ -12325,7 +12373,7 @@ mod tests {
                 CompactOptions {
                     compact_key_range: Some((get_key(0)..get_key(2)).into()),
                     compact_lsn_range: Some((Lsn(0x20)..Lsn(0x28)).into()),
-                    ..Default::default()
+                    ..CompactOptions::default_for_gc_compaction_unit_tests()
                 },
                 &ctx,
             )
@@ -12371,7 +12419,7 @@ mod tests {
                 CompactOptions {
                     compact_key_range: Some((get_key(3)..get_key(8)).into()),
                     compact_lsn_range: Some((Lsn(0x28)..Lsn(0x40)).into()),
-                    ..Default::default()
+                    ..CompactOptions::default_for_gc_compaction_unit_tests()
                 },
                 &ctx,
             )
@@ -12419,7 +12467,7 @@ mod tests {
                 CompactOptions {
                     compact_key_range: Some((get_key(0)..get_key(5)).into()),
                     compact_lsn_range: Some((Lsn(0x20)..Lsn(0x50)).into()),
-                    ..Default::default()
+                    ..CompactOptions::default_for_gc_compaction_unit_tests()
                 },
                 &ctx,
             )
@@ -12454,7 +12502,11 @@ mod tests {
 
         // final full compaction
         tline
-            .compact_with_gc(&cancel, CompactOptions::default(), &ctx)
+            .compact_with_gc(
+                &cancel,
+                CompactOptions::default_for_gc_compaction_unit_tests(),
+                &ctx,
+            )
             .await
             .unwrap();
         verify_result().await;
@@ -12564,7 +12616,7 @@ mod tests {
                 CompactOptions {
                     compact_key_range: None,
                     compact_lsn_range: None,
-                    ..Default::default()
+                    ..CompactOptions::default_for_gc_compaction_unit_tests()
                 },
                 &ctx,
             )

pageserver/src/tenant/timeline.rs

@@ -939,6 +939,20 @@ pub(crate) struct CompactOptions {
     /// Set job size for the GC compaction.
     /// This option is only used by GC compaction.
     pub sub_compaction_max_job_size_mb: Option<u64>,
+    /// Only for GC compaction.
+    /// If set, the compaction will compact the metadata layers. Should be only set to true in unit tests
+    /// because metadata compaction is not fully supported yet.
+    pub gc_compaction_do_metadata_compaction: bool,
+}
+
+impl CompactOptions {
+    #[cfg(test)]
+    pub fn default_for_gc_compaction_unit_tests() -> Self {
+        Self {
+            gc_compaction_do_metadata_compaction: true,
+            ..Default::default()
+        }
+    }
 }
 
 impl std::fmt::Debug for Timeline {
@@ -2185,6 +2199,7 @@ impl Timeline {
                     compact_lsn_range: None,
                     sub_compaction: false,
                     sub_compaction_max_job_size_mb: None,
+                    gc_compaction_do_metadata_compaction: false,
                 },
                 ctx,
             )

pageserver/src/tenant/timeline/compaction.rs

@@ -396,6 +396,7 @@ impl GcCompactionQueue {
                     }),
                     compact_lsn_range: None,
                     sub_compaction_max_job_size_mb: None,
+                    gc_compaction_do_metadata_compaction: false,
                 },
                 permit,
             );
@@ -512,6 +513,7 @@ impl GcCompactionQueue {
                     compact_key_range: Some(job.compact_key_range.into()),
                     compact_lsn_range: Some(job.compact_lsn_range.into()),
                     sub_compaction_max_job_size_mb: None,
+                    gc_compaction_do_metadata_compaction: false,
                 };
                 pending_tasks.push(GcCompactionQueueItem::SubCompactionJob {
                     options,
@@ -785,6 +787,8 @@ pub(crate) struct GcCompactJob {
     /// as specified here. The true range being compacted is `min_lsn/max_lsn` in [`GcCompactionJobDescription`].
     /// min_lsn will always <= the lower bound specified here, and max_lsn will always >= the upper bound specified here.
     pub compact_lsn_range: Range<Lsn>,
+    /// See [`CompactOptions::gc_compaction_do_metadata_compaction`].
+    pub do_metadata_compaction: bool,
 }
 
 impl GcCompactJob {
@@ -799,6 +803,7 @@ impl GcCompactJob {
                 .compact_lsn_range
                 .map(|x| x.into())
                 .unwrap_or(Lsn::INVALID..Lsn::MAX),
+            do_metadata_compaction: options.gc_compaction_do_metadata_compaction,
         }
     }
 }
@@ -3174,6 +3179,7 @@ impl Timeline {
                         dry_run: job.dry_run,
                         compact_key_range: start..end,
                         compact_lsn_range: job.compact_lsn_range.start..compact_below_lsn,
+                        do_metadata_compaction: false,
                     });
                     current_start = Some(end);
                 }
@@ -3236,7 +3242,7 @@ impl Timeline {
     async fn compact_with_gc_inner(
         self: &Arc<Self>,
         cancel: &CancellationToken,
-        job: GcCompactJob,
+        mut job: GcCompactJob,
         ctx: &RequestContext,
         yield_for_l0: bool,
     ) -> Result<CompactionOutcome, CompactionError> {
@@ -3244,6 +3250,28 @@ impl Timeline {
         // with legacy compaction tasks in the future. Always ensure the lock order is compaction -> gc.
         // Note that we already acquired the compaction lock when the outer `compact` function gets called.
 
+        // If the job is not configured to compact the metadata key range, shrink the key range
+        // to exclude the metadata key range. The check is done by checking if the end of the key range
+        // is larger than the start of the metadata key range. Note that metadata keys cover the entire
+        // second half of the keyspace, so it's enough to only check the end of the key range.
+        if !job.do_metadata_compaction
+            && job.compact_key_range.end > Key::metadata_key_range().start
+        {
+            tracing::info!(
+                "compaction for metadata key range is not supported yet, overriding compact_key_range from {} to {}",
+                job.compact_key_range.end,
+                Key::metadata_key_range().start
+            );
+            // Shrink the key range to exclude the metadata key range.
+            job.compact_key_range.end = Key::metadata_key_range().start;
+
+            // Skip the job if the key range completely lies within the metadata key range.
+            if job.compact_key_range.start >= job.compact_key_range.end {
+                tracing::info!("compact_key_range is empty, skipping compaction");
+                return Ok(CompactionOutcome::Done);
+            }
+        }
+
         let timer = Instant::now();
         let begin_timer = timer;
 

pageserver/src/tenant/timeline/walreceiver/connection_manager.rs

@@ -184,7 +184,7 @@ pub(super) async fn connection_manager_loop_step(
 
             // If we've not received any updates from the broker from a while, are waiting for WAL
             // and have no safekeeper connection or connection candidates, then it might be that
-            // the broker subscription is wedged. Drop the currrent subscription and re-subscribe
+            // the broker subscription is wedged. Drop the current subscription and re-subscribe
             // with the goal of unblocking it.
             _ = broker_reset_interval.tick() => {
                 let awaiting_lsn = wait_lsn_status.borrow().is_some();
@@ -192,7 +192,7 @@ pub(super) async fn connection_manager_loop_step(
                 let no_connection = connection_manager_state.wal_connection.is_none();
 
                 if awaiting_lsn && no_candidates && no_connection {
-                    tracing::warn!("No broker updates received for a while, but waiting for WAL. Re-setting stream ...");
+                    tracing::info!("No broker updates received for a while, but waiting for WAL. Re-setting stream ...");
                     broker_subscription = subscribe_for_timeline_updates(broker_client, id, cancel).await?;
                 }
             },

pageserver/src/utilization.rs

@@ -1,6 +1,6 @@
 //! An utilization metric which is used to decide on which pageserver to put next tenant.
 //!
-//! The metric is exposed via `GET /v1/utilization`. Refer and maintain it's openapi spec as the
+//! The metric is exposed via `GET /v1/utilization`. Refer and maintain its openapi spec as the
 //! truth.
 
 use std::path::Path;

pageserver/src/walingest.rs

@@ -32,9 +32,10 @@ use pageserver_api::reltag::{BlockNumber, RelTag, SlruKind};
 use pageserver_api::shard::ShardIdentity;
 use postgres_ffi::walrecord::*;
 use postgres_ffi::{
-    PgMajorVersion, TimestampTz, TransactionId, dispatch_pgversion, enum_pgversion,
-    enum_pgversion_dispatch, fsm_logical_to_physical, pg_constants,
+    PgMajorVersion, TransactionId, dispatch_pgversion, enum_pgversion, enum_pgversion_dispatch,
+    fsm_logical_to_physical, pg_constants,
 };
+use postgres_ffi_types::TimestampTz;
 use postgres_ffi_types::forknum::{FSM_FORKNUM, INIT_FORKNUM, MAIN_FORKNUM, VISIBILITYMAP_FORKNUM};
 use tracing::*;
 use utils::bin_ser::{DeserializeError, SerializeError};
@@ -1069,7 +1070,7 @@ impl WalIngest {
         // 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
+        // incremented! nextXid skips over < FirstNormalTransactionId when 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

pgxn/neon/file_cache.c

@@ -219,10 +219,6 @@ static char *lfc_path;
 static uint64 lfc_generation;
 static FileCacheControl *lfc_ctl;
 static bool lfc_do_prewarm;
-static shmem_startup_hook_type prev_shmem_startup_hook;
-#if PG_VERSION_NUM>=150000
-static shmem_request_hook_type prev_shmem_request_hook;
-#endif
 
 bool lfc_store_prefetch_result;
 bool lfc_prewarm_update_ws_estimation;
@@ -342,18 +338,14 @@ lfc_ensure_opened(void)
 	return true;
 }
 
-static void
-lfc_shmem_startup(void)
+void
+LfcShmemInit(void)
 {
 	bool		found;
 	static HASHCTL info;
 
-	if (prev_shmem_startup_hook)
-	{
-		prev_shmem_startup_hook();
-	}
-
-	LWLockAcquire(AddinShmemInitLock, LW_EXCLUSIVE);
+	if (lfc_max_size <= 0)
+		return;
 
 	lfc_ctl = (FileCacheControl *) ShmemInitStruct("lfc", sizeof(FileCacheControl), &found);
 	if (!found)
@@ -398,19 +390,16 @@ lfc_shmem_startup(void)
 			ConditionVariableInit(&lfc_ctl->cv[i]);
 
 	}
-	LWLockRelease(AddinShmemInitLock);
 }
 
-static void
-lfc_shmem_request(void)
+void
+LfcShmemRequest(void)
 {
-#if PG_VERSION_NUM>=150000
-	if (prev_shmem_request_hook)
-		prev_shmem_request_hook();
-#endif
-
-	RequestAddinShmemSpace(sizeof(FileCacheControl) + hash_estimate_size(SIZE_MB_TO_CHUNKS(lfc_max_size) + 1, FILE_CACHE_ENRTY_SIZE));
-	RequestNamedLWLockTranche("lfc_lock", 1);
+	if (lfc_max_size > 0)
+	{
+		RequestAddinShmemSpace(sizeof(FileCacheControl) + hash_estimate_size(SIZE_MB_TO_CHUNKS(lfc_max_size) + 1, FILE_CACHE_ENRTY_SIZE));
+		RequestNamedLWLockTranche("lfc_lock", 1);
+	}
 }
 
 static bool
@@ -642,18 +631,6 @@ lfc_init(void)
 							NULL,
 							NULL,
 							NULL);
-
-	if (lfc_max_size == 0)
-		return;
-
-	prev_shmem_startup_hook = shmem_startup_hook;
-	shmem_startup_hook = lfc_shmem_startup;
-#if PG_VERSION_NUM>=150000
-	prev_shmem_request_hook = shmem_request_hook;
-	shmem_request_hook = lfc_shmem_request;
-#else
-	lfc_shmem_request();
-#endif
 }
 
 FileCacheState*

pgxn/neon/libpagestore.c

@@ -90,6 +90,7 @@ typedef struct
 {
 	char		connstring[MAX_SHARDS][MAX_PAGESERVER_CONNSTRING_SIZE];
 	size_t		num_shards;
+	size_t		stripe_size;
 } ShardMap;
 
 /*
@@ -110,6 +111,11 @@ typedef struct
  * has changed since last access, and to detect and retry copying the value if
  * the postmaster changes the value concurrently. (Postmaster doesn't have a
  * PGPROC entry and therefore cannot use LWLocks.)
+ *
+ * stripe_size is now also part of ShardMap, although it is defined by separate GUC.
+ * Postgres doesn't provide any mechanism to enforce dependencies between GUCs,
+ * that it we we have to rely on order of GUC definition in config file.
+ * "neon.stripe_size" should be defined prior to "neon.pageserver_connstring"
  */
 typedef struct
 {
@@ -118,10 +124,6 @@ typedef struct
 	ShardMap	shard_map;
 } PagestoreShmemState;
 
-#if PG_VERSION_NUM >= 150000
-static shmem_request_hook_type prev_shmem_request_hook = NULL;
-#endif
-static shmem_startup_hook_type prev_shmem_startup_hook;
 static PagestoreShmemState *pagestore_shared;
 static uint64 pagestore_local_counter = 0;
 
@@ -234,7 +236,10 @@ ParseShardMap(const char *connstr, ShardMap *result)
 		p = sep + 1;
 	}
 	if (result)
+	{
 		result->num_shards = nshards;
+		result->stripe_size = stripe_size;
+	}
 
 	return true;
 }
@@ -295,12 +300,13 @@ AssignPageserverConnstring(const char *newval, void *extra)
  * last call, terminates all existing connections to all pageservers.
  */
 static void
-load_shard_map(shardno_t shard_no, char *connstr_p, shardno_t *num_shards_p)
+load_shard_map(shardno_t shard_no, char *connstr_p, shardno_t *num_shards_p, size_t* stripe_size_p)
 {
 	uint64		begin_update_counter;
 	uint64		end_update_counter;
 	ShardMap   *shard_map = &pagestore_shared->shard_map;
 	shardno_t	num_shards;
+	size_t		stripe_size;
 
 	/*
 	 * Postmaster can update the shared memory values concurrently, in which
@@ -315,6 +321,7 @@ load_shard_map(shardno_t shard_no, char *connstr_p, shardno_t *num_shards_p)
 		end_update_counter = pg_atomic_read_u64(&pagestore_shared->end_update_counter);
 
 		num_shards = shard_map->num_shards;
+		stripe_size = shard_map->stripe_size;
 		if (connstr_p && shard_no < MAX_SHARDS)
 			strlcpy(connstr_p, shard_map->connstring[shard_no], MAX_PAGESERVER_CONNSTRING_SIZE);
 		pg_memory_barrier();
@@ -349,6 +356,8 @@ load_shard_map(shardno_t shard_no, char *connstr_p, shardno_t *num_shards_p)
 
 	if (num_shards_p)
 		*num_shards_p = num_shards;
+	if (stripe_size_p)
+		*stripe_size_p = stripe_size;
 }
 
 #define MB (1024*1024)
@@ -357,9 +366,10 @@ shardno_t
 get_shard_number(BufferTag *tag)
 {
 	shardno_t	n_shards;
+	size_t		stripe_size;
 	uint32		hash;
 
-	load_shard_map(0, NULL, &n_shards);
+	load_shard_map(0, NULL, &n_shards, &stripe_size);
 
 #if PG_MAJORVERSION_NUM < 16
 	hash = murmurhash32(tag->rnode.relNode);
@@ -412,7 +422,7 @@ pageserver_connect(shardno_t shard_no, int elevel)
 	 * Note that connstr is used both during connection start, and when we
 	 * log the successful connection.
 	 */
-	load_shard_map(shard_no, connstr, NULL);
+	load_shard_map(shard_no, connstr, NULL, NULL);
 
 	switch (shard->state)
 	{
@@ -1284,18 +1294,12 @@ check_neon_id(char **newval, void **extra, GucSource source)
 	return **newval == '\0' || HexDecodeString(id, *newval, 16);
 }
 
-static Size
-PagestoreShmemSize(void)
-{
-	return add_size(sizeof(PagestoreShmemState), NeonPerfCountersShmemSize());
-}
 
-static bool
+void
 PagestoreShmemInit(void)
 {
 	bool		found;
 
-	LWLockAcquire(AddinShmemInitLock, LW_EXCLUSIVE);
 	pagestore_shared = ShmemInitStruct("libpagestore shared state",
 									   sizeof(PagestoreShmemState),
 									   &found);
@@ -1306,44 +1310,12 @@ PagestoreShmemInit(void)
 		memset(&pagestore_shared->shard_map, 0, sizeof(ShardMap));
 		AssignPageserverConnstring(page_server_connstring, NULL);
 	}
-
-	NeonPerfCountersShmemInit();
-
-	LWLockRelease(AddinShmemInitLock);
-	return found;
 }
 
-static void
-pagestore_shmem_startup_hook(void)
+void
+PagestoreShmemRequest(void)
 {
-	if (prev_shmem_startup_hook)
-		prev_shmem_startup_hook();
-
-	PagestoreShmemInit();
-}
-
-static void
-pagestore_shmem_request(void)
-{
-#if PG_VERSION_NUM >= 150000
-	if (prev_shmem_request_hook)
-		prev_shmem_request_hook();
-#endif
-
-	RequestAddinShmemSpace(PagestoreShmemSize());
-}
-
-static void
-pagestore_prepare_shmem(void)
-{
-#if PG_VERSION_NUM >= 150000
-	prev_shmem_request_hook = shmem_request_hook;
-	shmem_request_hook = pagestore_shmem_request;
-#else
-	pagestore_shmem_request();
-#endif
-	prev_shmem_startup_hook = shmem_startup_hook;
-	shmem_startup_hook = pagestore_shmem_startup_hook;
+	RequestAddinShmemSpace(sizeof(PagestoreShmemState));
 }
 
 /*
@@ -1352,8 +1324,6 @@ pagestore_prepare_shmem(void)
 void
 pg_init_libpagestore(void)
 {
-	pagestore_prepare_shmem();
-
 	DefineCustomStringVariable("neon.pageserver_connstring",
 							   "connection string to the page server",
 							   NULL,
@@ -1504,8 +1474,6 @@ pg_init_libpagestore(void)
 							0,
 							NULL, NULL, NULL);
 
-	relsize_hash_init();
-
 	if (page_server != NULL)
 		neon_log(ERROR, "libpagestore already loaded");
 

pgxn/neon/neon.c

@@ -22,6 +22,7 @@
 #include "replication/slot.h"
 #include "replication/walsender.h"
 #include "storage/proc.h"
+#include "storage/ipc.h"
 #include "funcapi.h"
 #include "access/htup_details.h"
 #include "utils/builtins.h"
@@ -59,11 +60,15 @@ static ExecutorEnd_hook_type prev_ExecutorEnd = NULL;
 static void neon_ExecutorStart(QueryDesc *queryDesc, int eflags);
 static void neon_ExecutorEnd(QueryDesc *queryDesc);
 
-#if PG_MAJORVERSION_NUM >= 16
 static shmem_startup_hook_type prev_shmem_startup_hook;
-
 static void neon_shmem_startup_hook(void);
+static void neon_shmem_request_hook(void);
+
+#if PG_MAJORVERSION_NUM >= 15
+static shmem_request_hook_type prev_shmem_request_hook = NULL;
 #endif
+
+
 #if PG_MAJORVERSION_NUM >= 17
 uint32		WAIT_EVENT_NEON_LFC_MAINTENANCE;
 uint32		WAIT_EVENT_NEON_LFC_READ;
@@ -450,15 +455,44 @@ _PG_init(void)
 	 */
 #if PG_VERSION_NUM >= 160000
 	load_file("$libdir/neon_rmgr", false);
-
-	prev_shmem_startup_hook = shmem_startup_hook;
-	shmem_startup_hook = neon_shmem_startup_hook;
 #endif
 
 	/* dummy call to a Rust function in the communicator library, to check that it works */
 	(void) communicator_dummy(123);
 
+	/*
+	 * Initializing a pre-loaded Postgres extension happens in three stages:
+	 *
+	 * 1. _PG_init() is called early at postmaster startup. In this stage, no
+	 *    shared memory has been allocated yet. Core Postgres GUCs have been
+	 *    initialized from the config files, but notably, MaxBackends has not
+	 *    calculated yet. In this stage, we must register any extension GUCs
+	 *    and can do other early initialization that doesn't depend on shared
+	 *    memory. In this stage we must also register "shmem request" and
+	 *    "shmem starutup" hooks, to be called in stages 2 and 3.
+	 *
+	 * 2. After MaxBackends have been calculated, the "shmem request" hooks
+	 *    are called. The hooks can reserve shared memory by calling
+	 *    RequestAddinShmemSpace and RequestNamedLWLockTranche().  The "shmem
+	 *    request hooks" are a new mechanism in Postgres v15. In v14 and
+	 *    below, you had to make those Requests in stage 1 already, which
+	 *    means they could not depend on MaxBackends. (See hack in
+	 *    NeonPerfCountersShmemRequest())
+	 *
+	 * 3. After some more runtime-computed GUCs that affect the amount of
+	 *    shared memory needed have been calculated, the "shmem startup" hooks
+	 *    are called. In this stage, we allocate any shared memory, LWLocks
+	 *    and other shared resources.
+	 *
+	 * Here, in the 'neon' extension, we register just one shmem request hook
+	 * and one startup hook, which call into functions in all the subsystems
+	 * that are part of the extension. On v14, the ShmemRequest functions are
+	 * called in stage 1, and on v15 onwards they are called in stage 2.
+	 */
+
+	/* Stage 1: Define GUCs, and other early intialization */
 	pg_init_libpagestore();
+	relsize_hash_init();
 	lfc_init();
 	pg_init_walproposer();
 	init_lwlsncache();
@@ -543,6 +577,15 @@ _PG_init(void)
 							PGC_POSTMASTER,
 							0,
 							NULL, NULL, NULL);
+
+	DefineCustomStringVariable(
+							"neon.privileged_role_name",
+							"Name of the 'weak' superuser role, which we give to the users",
+							NULL,
+							&privileged_role_name,
+							"neon_superuser",
+							PGC_POSTMASTER, 0, NULL, NULL, NULL);
+
 	/*
 	 * Important: This must happen after other parts of the extension are
 	 * loaded, otherwise any settings to GUCs that were set before the
@@ -552,6 +595,22 @@ _PG_init(void)
 
 	ReportSearchPath();
 
+	/*
+	 * Register initialization hooks for stage 2. (On v14, there's no "shmem
+	 * request" hooks, so call the ShmemRequest functions immediately.)
+	 */
+#if PG_VERSION_NUM >= 150000
+	prev_shmem_request_hook = shmem_request_hook;
+	shmem_request_hook = neon_shmem_request_hook;
+#else
+	neon_shmem_request_hook();
+#endif
+
+	/* Register hooks for stage 3 */
+	prev_shmem_startup_hook = shmem_startup_hook;
+	shmem_startup_hook = neon_shmem_startup_hook;
+
+	/* Other misc initialization */
 	prev_ExecutorStart = ExecutorStart_hook;
 	ExecutorStart_hook = neon_ExecutorStart;
 	prev_ExecutorEnd = ExecutorEnd_hook;
@@ -637,7 +696,34 @@ approximate_working_set_size(PG_FUNCTION_ARGS)
 		PG_RETURN_INT32(dc);
 }
 
-#if PG_MAJORVERSION_NUM >= 16
+/*
+ * Initialization stage 2: make requests for the amount of shared memory we
+ * will need.
+ *
+ * For a high-level explanation of the initialization process, see _PG_init().
+ */
+static void
+neon_shmem_request_hook(void)
+{
+#if PG_VERSION_NUM >= 150000
+	if (prev_shmem_request_hook)
+		prev_shmem_request_hook();
+#endif
+
+	LfcShmemRequest();
+	NeonPerfCountersShmemRequest();
+	PagestoreShmemRequest();
+	RelsizeCacheShmemRequest();
+	WalproposerShmemRequest();
+	LwLsnCacheShmemRequest();
+}
+
+
+/*
+ * Initialization stage 3: Initialize shared memory.
+ *
+ * For a high-level explanation of the initialization process, see _PG_init().
+ */
 static void
 neon_shmem_startup_hook(void)
 {
@@ -645,6 +731,15 @@ neon_shmem_startup_hook(void)
 	if (prev_shmem_startup_hook)
 		prev_shmem_startup_hook();
 
+	LWLockAcquire(AddinShmemInitLock, LW_EXCLUSIVE);
+
+	LfcShmemInit();
+	NeonPerfCountersShmemInit();
+	PagestoreShmemInit();
+	RelsizeCacheShmemInit();
+	WalproposerShmemInit();
+	LwLsnCacheShmemInit();
+
 #if PG_MAJORVERSION_NUM >= 17
 	WAIT_EVENT_NEON_LFC_MAINTENANCE = WaitEventExtensionNew("Neon/FileCache_Maintenance");
 	WAIT_EVENT_NEON_LFC_READ = WaitEventExtensionNew("Neon/FileCache_Read");
@@ -657,8 +752,9 @@ neon_shmem_startup_hook(void)
 	WAIT_EVENT_NEON_PS_READ = WaitEventExtensionNew("Neon/PS_ReadIO");
 	WAIT_EVENT_NEON_WAL_DL = WaitEventExtensionNew("Neon/WAL_Download");
 #endif
+
+	LWLockRelease(AddinShmemInitLock);
 }
-#endif
 
 /*
  * ExecutorStart hook: start up tracking if needed

pgxn/neon/neon.h

@@ -16,7 +16,6 @@
 extern char *neon_auth_token;
 extern char *neon_timeline;
 extern char *neon_tenant;
-
 extern char *wal_acceptors_list;
 extern int	wal_acceptor_reconnect_timeout;
 extern int	wal_acceptor_connection_timeout;
@@ -71,4 +70,19 @@ extern PGDLLEXPORT void WalProposerSync(int argc, char *argv[]);
 extern PGDLLEXPORT void WalProposerMain(Datum main_arg);
 extern PGDLLEXPORT void LogicalSlotsMonitorMain(Datum main_arg);
 
+extern void LfcShmemRequest(void);
+extern void PagestoreShmemRequest(void);
+extern void RelsizeCacheShmemRequest(void);
+extern void WalproposerShmemRequest(void);
+extern void LwLsnCacheShmemRequest(void);
+extern void NeonPerfCountersShmemRequest(void);
+
+extern void LfcShmemInit(void);
+extern void PagestoreShmemInit(void);
+extern void RelsizeCacheShmemInit(void);
+extern void WalproposerShmemInit(void);
+extern void LwLsnCacheShmemInit(void);
+extern void NeonPerfCountersShmemInit(void);
+
+
 #endif							/* NEON_H */

pgxn/neon/neon_ddl_handler.c

@@ -13,7 +13,7 @@
  *        accumulate changes. On subtransaction commit, the top of the stack
  *        is merged with the table below it.
  *
- *    Support event triggers for neon_superuser
+ *    Support event triggers for {privileged_role_name}
  *
  * IDENTIFICATION
  *	 contrib/neon/neon_dll_handler.c
@@ -49,6 +49,7 @@
 
 #include "neon_ddl_handler.h"
 #include "neon_utils.h"
+#include "neon.h"
 
 static ProcessUtility_hook_type PreviousProcessUtilityHook = NULL;
 static fmgr_hook_type next_fmgr_hook = NULL;
@@ -541,11 +542,11 @@ NeonXactCallback(XactEvent event, void *arg)
 }
 
 static bool
-RoleIsNeonSuperuser(const char *role_name)
+IsPrivilegedRole(const char *role_name)
 {
 	Assert(role_name);
 
-	return strcmp(role_name, "neon_superuser") == 0;
+	return strcmp(role_name, privileged_role_name) == 0;
 }
 
 static void
@@ -578,8 +579,9 @@ HandleCreateDb(CreatedbStmt *stmt)
 	{
 		const char *owner_name = defGetString(downer);
 
-		if (RoleIsNeonSuperuser(owner_name))
-			elog(ERROR, "can't create a database with owner neon_superuser");
+		if (IsPrivilegedRole(owner_name))
+			elog(ERROR, "could not create a database with owner %s", privileged_role_name);
+
 		entry->owner = get_role_oid(owner_name, false);
 	}
 	else
@@ -609,8 +611,9 @@ HandleAlterOwner(AlterOwnerStmt *stmt)
 		memset(entry->old_name, 0, sizeof(entry->old_name));
 
 	new_owner = get_rolespec_name(stmt->newowner);
-	if (RoleIsNeonSuperuser(new_owner))
-		elog(ERROR, "can't alter owner to neon_superuser");
+	if (IsPrivilegedRole(new_owner))
+		elog(ERROR, "could not alter owner to %s", privileged_role_name);
+
 	entry->owner = get_role_oid(new_owner, false);
 	entry->type = Op_Set;
 }
@@ -716,8 +719,8 @@ HandleAlterRole(AlterRoleStmt *stmt)
 	InitRoleTableIfNeeded();
 
 	role_name = get_rolespec_name(stmt->role);
-	if (RoleIsNeonSuperuser(role_name) && !superuser())
-		elog(ERROR, "can't ALTER neon_superuser");
+	if (IsPrivilegedRole(role_name) && !superuser())
+		elog(ERROR, "could not ALTER %s", privileged_role_name);
 
 	dpass = NULL;
 	foreach(option, stmt->options)
@@ -831,7 +834,7 @@ HandleRename(RenameStmt *stmt)
  *
  * In vanilla only superuser can create Event Triggers.
  *
- * We allow it for neon_superuser by temporary switching to superuser. But as
+ * We allow it for {privileged_role_name} by temporary switching to superuser. But as
  * far as event trigger can fire in superuser context we should protect
  * superuser from execution of arbitrary user's code.
  *
@@ -891,7 +894,7 @@ force_noop(FmgrInfo *finfo)
  * Also skip executing Event Triggers when GUC neon.event_triggers has been
  * set to false. This might be necessary to be able to connect again after a
  * LOGIN Event Trigger has been installed that would prevent connections as
- * neon_superuser.
+ * {privileged_role_name}.
  */
 static void
 neon_fmgr_hook(FmgrHookEventType event, FmgrInfo *flinfo, Datum *private)
@@ -910,24 +913,24 @@ neon_fmgr_hook(FmgrHookEventType event, FmgrInfo *flinfo, Datum *private)
 	}
 
 	/*
-	 * The neon_superuser role can use the GUC neon.event_triggers to disable
+	 * The {privileged_role_name} role can use the GUC neon.event_triggers to disable
 	 * firing Event Trigger.
 	 *
 	 *   SET neon.event_triggers TO false;
 	 *
-	 * This only applies to the neon_superuser role though, and only allows
-	 * skipping Event Triggers owned by neon_superuser, which we check by
-	 * proxy of the Event Trigger function being owned by neon_superuser.
+	 * This only applies to the {privileged_role_name} role though, and only allows
+	 * skipping Event Triggers owned by {privileged_role_name}, which we check by
+	 * proxy of the Event Trigger function being owned by {privileged_role_name}.
 	 *
-	 * A role that is created in role neon_superuser should be allowed to also
+	 * A role that is created in role {privileged_role_name} should be allowed to also
 	 * benefit from the neon_event_triggers GUC, and will be considered the
-	 * same as the neon_superuser role.
+	 * same as the {privileged_role_name} role.
 	 */
 	if (event == FHET_START
 		&& !neon_event_triggers
-		&& is_neon_superuser())
+		&& is_privileged_role())
 	{
-		Oid neon_superuser_oid = get_role_oid("neon_superuser", false);
+		Oid weak_superuser_oid = get_role_oid(privileged_role_name, false);
 
 		/* Find the Function Attributes (owner Oid, security definer) */
 		const char *fun_owner_name = NULL;
@@ -937,8 +940,8 @@ neon_fmgr_hook(FmgrHookEventType event, FmgrInfo *flinfo, Datum *private)
 		LookupFuncOwnerSecDef(flinfo->fn_oid, &fun_owner, &fun_is_secdef);
 		fun_owner_name = GetUserNameFromId(fun_owner, false);
 
-		if (RoleIsNeonSuperuser(fun_owner_name)
-			|| has_privs_of_role(fun_owner, neon_superuser_oid))
+		if (IsPrivilegedRole(fun_owner_name)
+			|| has_privs_of_role(fun_owner, weak_superuser_oid))
 		{
 			elog(WARNING,
 				 "Skipping Event Trigger: neon.event_triggers is false");
@@ -1149,13 +1152,13 @@ ProcessCreateEventTrigger(
 	}
 
 	/*
-	 * Allow neon_superuser to create Event Trigger, while keeping the
+	 * Allow {privileged_role_name} to create Event Trigger, while keeping the
 	 * ownership of the object.
 	 *
 	 * For that we give superuser membership to the role for the execution of
 	 * the command.
 	 */
-	if (IsTransactionState() && is_neon_superuser())
+	if (IsTransactionState() && is_privileged_role())
 	{
 		/* Find the Event Trigger function Oid */
 		Oid func_oid = LookupFuncName(stmt->funcname, 0, NULL, false);
@@ -1232,7 +1235,7 @@ ProcessCreateEventTrigger(
 		 *
 		 * That way [ ALTER | DROP ] EVENT TRIGGER commands just work.
 		 */
-		if (IsTransactionState() && is_neon_superuser())
+		if (IsTransactionState() && is_privileged_role())
 		{
 			if (!current_user_is_super)
 			{
@@ -1352,19 +1355,17 @@ NeonProcessUtility(
 }
 
 /*
- * Only neon_superuser is granted privilege to edit neon.event_triggers GUC.
+ * Only {privileged_role_name} is granted privilege to edit neon.event_triggers GUC.
  */
 static void
 neon_event_triggers_assign_hook(bool newval, void *extra)
 {
-	/* MyDatabaseId == InvalidOid || !OidIsValid(GetUserId())	 */
-
-	if (IsTransactionState() && !is_neon_superuser())
+	if (IsTransactionState() && !is_privileged_role())
 	{
 		ereport(ERROR,
 				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
 				 errmsg("permission denied to set neon.event_triggers"),
-				 errdetail("Only \"neon_superuser\" is allowed to set the GUC")));
+				 errdetail("Only \"%s\" is allowed to set the GUC", privileged_role_name)));
 	}
 }