Save coverage data upon completion of regress-tests; Remove legacy step "Build coverage report"

[compute] fix: background worker that collects installed extension metrics now updates collection interval (#12277 )
## Problem Previously, the background worker that collects the list of installed extensions across DBs had a timeout set to 1 hour. This cause a problem with computes that had a `suspend_timeout` > 1 hour as this collection was treated as activity, preventing compute shutdown. Issue: https://github.com/neondatabase/cloud/issues/30147 ## Summary of changes Passing the `suspend_timeout` as part of the `ComputeSpec` so that any updates to this are taken into account by the background worker and updates its collection interval.
2026-07-06 13:40:37 +00:00 · 2025-07-03 13:50:45 +03:00 · 2025-06-30 22:12:37 +00:00 · 2025-06-30 21:36:15 +00:00 · 2025-06-30 14:09:50 +00:00 · 2025-06-30 12:44:17 +00:00
314 changed files with 7869 additions and 18385 deletions
--- a/.dockerignore
+++ b/.dockerignore
@@ -4,6 +4,7 @@
 !Cargo.lock
 !Cargo.toml
 !Makefile
+!postgres.mk
 !rust-toolchain.toml
 !scripts/ninstall.sh
 !docker-compose/run-tests.sh
--- a/.github/workflows/_build-and-test-locally.yml
+++ b/.github/workflows/_build-and-test-locally.yml
@@ -391,10 +391,6 @@ jobs:
          PAGESERVER_VIRTUAL_FILE_IO_ENGINE: tokio-epoll-uring
          USE_LFC: ${{ matrix.lfc_state == 'with-lfc' && 'true' || 'false' }}

-      # Temporary disable this step until we figure out why it's so flaky
-      # Ref https://github.com/neondatabase/neon/issues/4540
      - name: Merge and upload coverage data
-        if: |
-          false &&
-          inputs.build-type == 'debug' && matrix.pg_version == 'v16'
+        if: inputs.build-type == 'debug'
        uses: ./.github/actions/save-coverage-data
--- a/.github/workflows/build-macos.yml
+++ b/.github/workflows/build-macos.yml
@@ -94,11 +94,6 @@ jobs:
        run: |
          make "neon-pg-ext-${{ matrix.postgres-version }}" -j$(sysctl -n hw.ncpu)

-      - name: Get postgres headers ${{ matrix.postgres-version }}
-        if: steps.cache_pg.outputs.cache-hit != 'true'
-        run: |
-          make postgres-headers-${{ matrix.postgres-version }} -j$(sysctl -n hw.ncpu)
-
      - name: Upload "pg_install/${{ matrix.postgres-version }}" artifact
        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
        with:
@@ -140,6 +135,12 @@ jobs:
          name: pg_install--v17
          path: pg_install/v17

+      # `actions/download-artifact` doesn't preserve permissions:
+      # https://github.com/actions/download-artifact?tab=readme-ov-file#permission-loss
+      - name: Make pg_install/v*/bin/* executable
+        run: |
+          chmod +x pg_install/v*/bin/*
+
      - name: Cache walproposer-lib
        id: cache_walproposer_lib
        uses: actions/cache@5a3ec84eff668545956fd18022155c47e93e2684 # v4.2.3
@@ -167,7 +168,7 @@ jobs:
      - name: Build walproposer-lib (only for v17)
        if: steps.cache_walproposer_lib.outputs.cache-hit != 'true'
        run:
-          make walproposer-lib -j$(sysctl -n hw.ncpu)
+          make walproposer-lib -j$(sysctl -n hw.ncpu) PG_INSTALL_CACHED=1

      - name: Upload "build/walproposer-lib" artifact
        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
--- a/.github/workflows/build_and_test.yml
+++ b/.github/workflows/build_and_test.yml
@@ -69,7 +69,7 @@ jobs:
          submodules: true

      - name: Check for file changes
-        uses: step-security/paths-filter@v3
+        uses: dorny/paths-filter@de90cc6fb38fc0963ad72b210f1f284cd68cea36  # v3.0.2
        id: files-changed
        with:
          token: ${{ secrets.GITHUB_TOKEN }}
@@ -484,21 +484,6 @@ jobs:
      - name: Merge coverage data
        run: scripts/coverage "--profraw-prefix=$GITHUB_JOB" --dir=/tmp/coverage merge

-      - name: Build coverage report
-        env:
-          COMMIT_URL: ${{ github.server_url }}/${{ github.repository }}/commit/${{ github.event.pull_request.head.sha || github.sha }}
-        run: |
-          scripts/coverage --dir=/tmp/coverage \
-            report \
-            --input-objects=/tmp/coverage/binaries.list \
-            --commit-url=${COMMIT_URL} \
-            --format=github
-
-          scripts/coverage --dir=/tmp/coverage \
-            report \
-            --input-objects=/tmp/coverage/binaries.list \
-            --format=lcov
-
      - name: Build coverage report NEW
        id: upload-coverage-report-new
        env:
@@ -511,6 +496,13 @@ jobs:
          CURRENT="${COMMIT_SHA}"
          BASELINE="$(git merge-base $BASE_SHA $CURRENT)"

+          mkdir /tmp/coverage/report
+
+          scripts/coverage --dir=/tmp/coverage \
+            report \
+            --input-objects=/tmp/coverage/binaries.list \
+            --format=lcov
+
          cp /tmp/coverage/report/lcov.info ./${CURRENT}.info

          GENHTML_ARGS="--ignore-errors path,unmapped,empty --synthesize-missing --demangle-cpp rustfilt --output-directory lcov-html ${CURRENT}.info"
--- a/.github/workflows/large_oltp_benchmark.yml
+++ b/.github/workflows/large_oltp_benchmark.yml
@@ -153,7 +153,7 @@ jobs:
        PERF_TEST_RESULT_CONNSTR: "${{ secrets.PERF_TEST_RESULT_CONNSTR }}"

    - name: Benchmark database maintenance
-      if: ${{ matrix.test_maintenance == 'true' }}
+      if: ${{ matrix.test_maintenance }}
      uses: ./.github/actions/run-python-test-set
      with:
        build_type: ${{ env.BUILD_TYPE }}
--- a/.github/workflows/neon_extra_builds.yml
+++ b/.github/workflows/neon_extra_builds.yml
@@ -53,7 +53,7 @@ jobs:
          submodules: true

      - name: Check for Postgres changes
-        uses: step-security/paths-filter@v3
+        uses: dorny/paths-filter@1441771bbfdd59dcd748680ee64ebd8faab1a242  #v3
        id: files_changed
        with:
          token: ${{ github.token }}
--- a/.github/workflows/pre-merge-checks.yml
+++ b/.github/workflows/pre-merge-checks.yml
@@ -34,7 +34,7 @@ jobs:

      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2

-      - uses: step-security/changed-files@3dbe17c78367e7d60f00d78ae6781a35be47b4a1 # v45.0.1
+      - uses: tj-actions/changed-files@ed68ef82c095e0d48ec87eccea555d944a631a4c # v46.0.5
        id: python-src
        with:
          files: |
@@ -45,7 +45,7 @@ jobs:
            poetry.lock
            pyproject.toml

-      - uses: step-security/changed-files@3dbe17c78367e7d60f00d78ae6781a35be47b4a1 # v45.0.1
+      - uses: tj-actions/changed-files@ed68ef82c095e0d48ec87eccea555d944a631a4c # v46.0.5
        id: rust-src
        with:
          files: |
--- a/.github/workflows/proxy-benchmark.yml
+++ b/.github/workflows/proxy-benchmark.yml
@@ -0,0 +1,84 @@
+name: Periodic proxy performance test on unit-perf hetzner runner
+
+on:
+  push: # TODO: remove after testing
+    branches:
+      - test-proxy-bench # Runs on pushes to branches starting with test-proxy-bench
+  # schedule:
+    # * is a special character in YAML so you have to quote this string
+    #        ┌───────────── minute (0 - 59)
+    #        │ ┌───────────── hour (0 - 23)
+    #        │ │ ┌───────────── day of the month (1 - 31)
+    #        │ │ │ ┌───────────── month (1 - 12 or JAN-DEC)
+    #        │ │ │ │ ┌───────────── day of the week (0 - 6 or SUN-SAT)
+    # - cron: '0 5 * * *' # Runs at 5 UTC once a day
+  workflow_dispatch: # adds an ability to run this manually
+
+defaults:
+  run:
+    shell: bash -euo pipefail {0}
+
+concurrency:
+  group: ${{ github.workflow }}
+  cancel-in-progress: false
+
+permissions:
+  contents: read
+
+jobs:
+  run_periodic_proxybench_test:
+    permissions:
+      id-token: write # aws-actions/configure-aws-credentials
+      statuses: write
+      contents: write
+      pull-requests: write
+    runs-on: [self-hosted, unit-perf]
+    timeout-minutes: 60  # 1h timeout
+    container:
+      image: ghcr.io/neondatabase/build-tools:pinned-bookworm
+      credentials:
+        username: ${{ github.actor }}
+        password: ${{ secrets.GITHUB_TOKEN }}
+      options: --init
+    steps:
+    - name: Checkout proxy-bench Repo
+      uses: actions/checkout@v4
+      with:
+        repository: neondatabase/proxy-bench
+        path: proxy-bench
+
+    - name: Set up the environment which depends on $RUNNER_TEMP on nvme drive
+      id: set-env
+      shell: bash -euxo pipefail {0}
+      run: |
+        PROXY_BENCH_PATH=$(realpath ./proxy-bench)
+        {
+          echo "PROXY_BENCH_PATH=$PROXY_BENCH_PATH"
+          echo "NEON_DIR=${RUNNER_TEMP}/neon"
+          echo "TEST_OUTPUT=${PROXY_BENCH_PATH}/test_output"
+          echo ""
+        } >> "$GITHUB_ENV"
+
+    - name: Run proxy-bench
+      run: ${PROXY_BENCH_PATH}/run.sh
+
+    - name: Ingest Bench Results # neon repo script
+      if: always()
+      run: |
+        mkdir -p $TEST_OUTPUT
+        python $NEON_DIR/scripts/proxy_bench_results_ingest.py --out $TEST_OUTPUT
+
+    - name: Push Metrics to Proxy perf database
+      if: always()
+      env:
+        PERF_TEST_RESULT_CONNSTR: "${{ secrets.PROXY_TEST_RESULT_CONNSTR }}"
+        REPORT_FROM: $TEST_OUTPUT
+      run: $NEON_DIR/scripts/generate_and_push_perf_report.sh
+
+    - name: Docker cleanup
+      if: always()
+      run: docker compose down
+
+    - name: Notify Failure
+      if: failure()
+      run: echo "Proxy bench job failed" && exit 1
--- a/.gitignore
+++ b/.gitignore
@@ -14,7 +14,6 @@ neon.iml
 /.neon
 /integration_tests/.neon
 compaction-suite-results.*
-pgxn/neon/communicator/communicator_bindings.h

 # Coverage
 *.profraw
--- a/Cargo.lock
+++ b/Cargo.lock
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -8,7 +8,6 @@ members = [
    "pageserver/compaction",
    "pageserver/ctl",
    "pageserver/client",
-    "pageserver/client_grpc",
    "pageserver/pagebench",
    "pageserver/page_api",
    "proxy",
@@ -24,6 +23,7 @@ members = [
    "libs/pageserver_api",
    "libs/postgres_ffi",
    "libs/postgres_ffi_types",
+    "libs/postgres_versioninfo",
    "libs/safekeeper_api",
    "libs/desim",
    "libs/neon-shmem",
@@ -34,7 +34,6 @@ members = [
    "libs/pq_proto",
    "libs/tenant_size_model",
    "libs/metrics",
-    "libs/neonart",
    "libs/postgres_connection",
    "libs/remote_storage",
    "libs/tracing-utils",
@@ -47,7 +46,6 @@ members = [
    "libs/proxy/postgres-types2",
    "libs/proxy/tokio-postgres2",
    "endpoint_storage",
-    "pgxn/neon/communicator",
 ]

 [workspace.package]
@@ -91,7 +89,6 @@ clap = { version = "4.0", features = ["derive", "env"] }
 clashmap = { version = "1.0", features = ["raw-api"] }
 comfy-table = "7.1"
 const_format = "0.2"
-crossbeam-utils = "0.8.21"
 crc32c = "0.6"
 diatomic-waker = { version = "0.2.3" }
 either = "1.8"
@@ -150,12 +147,12 @@ parquet = { version = "53", default-features = false, features = ["zstd"] }
 parquet_derive = "53"
 pbkdf2 = { version = "0.12.1", features = ["simple", "std"] }
 pem = "3.0.3"
-peekable = "0.3.0"
 pin-project-lite = "0.2"
 pprof = { version = "0.14", features = ["criterion", "flamegraph", "frame-pointer", "prost-codec"] }
 procfs = "0.16"
 prometheus = {version = "0.13", default-features=false, features = ["process"]} # removes protobuf dependency
 prost = "0.13.5"
+prost-types = "0.13.5"
 rand = "0.8"
 redis = { version = "0.29.2", features = ["tokio-rustls-comp", "keep-alive"] }
 regex = "1.10.2"
@@ -179,13 +176,13 @@ serde_json = "1"
 serde_path_to_error = "0.1"
 serde_with = { version = "3", features = [ "base64" ] }
 serde_assert = "0.5.0"
+serde_repr = "0.1.20"
 sha2 = "0.10.2"
 signal-hook = "0.3"
 smallvec = "1.11"
 smol_str = { version = "0.2.0", features = ["serde"] }
 socket2 = "0.5"
 spki = "0.7.3"
-spin = "0.9.8"
 strum = "0.26"
 strum_macros = "0.26"
 "subtle"  = "2.5.0"
@@ -197,6 +194,7 @@ thiserror = "1.0"
 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"] }
+tokio-epoll-uring = { git = "https://github.com/neondatabase/tokio-epoll-uring.git" , branch = "main" }
 tokio-io-timeout = "1.2.0"
 tokio-postgres-rustls = "0.12.0"
 tokio-rustls = { version = "0.26.0", default-features = false, features = ["tls12", "ring"]}
@@ -238,9 +236,6 @@ x509-cert = { version = "0.2.5" }
 env_logger = "0.11"
 log = "0.4"

-tokio-epoll-uring = { git = "https://github.com/neondatabase/tokio-epoll-uring.git" , branch = "main" }
-uring-common = { git = "https://github.com/neondatabase/tokio-epoll-uring.git" , branch = "main" }
-
 ## Libraries from neondatabase/ git forks, ideally with changes to be upstreamed
 postgres = { git = "https://github.com/neondatabase/rust-postgres.git", branch = "neon" }
 postgres-protocol = { git = "https://github.com/neondatabase/rust-postgres.git", branch = "neon" }
@@ -260,18 +255,16 @@ desim = { version = "0.1", path = "./libs/desim" }
 endpoint_storage = { version = "0.0.1", path = "./endpoint_storage/" }
 http-utils = { version = "0.1", path = "./libs/http-utils/" }
 metrics = { version = "0.1", path = "./libs/metrics/" }
-neonart = { version = "0.1", path = "./libs/neonart/" }
-neon-shmem = { version = "0.1", path = "./libs/neon-shmem/" }
 pageserver = { path = "./pageserver" }
 pageserver_api = { version = "0.1", path = "./libs/pageserver_api/" }
 pageserver_client = { path = "./pageserver/client" }
-pageserver_client_grpc = { path = "./pageserver/client_grpc" }
 pageserver_compaction = { version = "0.1", path = "./pageserver/compaction/" }
 pageserver_page_api = { path = "./pageserver/page_api" }
 postgres_backend = { version = "0.1", path = "./libs/postgres_backend/" }
 postgres_connection = { version = "0.1", path = "./libs/postgres_connection/" }
 postgres_ffi = { version = "0.1", path = "./libs/postgres_ffi/" }
 postgres_ffi_types = { version = "0.1", path = "./libs/postgres_ffi_types/" }
+postgres_versioninfo = { version = "0.1", path = "./libs/postgres_versioninfo/" }
 postgres_initdb = { path = "./libs/postgres_initdb" }
 posthog_client_lite = { version = "0.1", path = "./libs/posthog_client_lite" }
 pq_proto = { version = "0.1", path = "./libs/pq_proto/" }
@@ -291,7 +284,6 @@ walproposer = { version = "0.1", path = "./libs/walproposer/" }
 workspace_hack = { version = "0.1", path = "./workspace_hack/" }

 ## Build dependencies
-cbindgen = "0.28.0"
 criterion = "0.5.1"
 rcgen = "0.13"
 rstest = "0.18"
--- a/1
+++ b/1
@@ -40,6 +40,7 @@ COPY --chown=nonroot vendor/postgres-v16 vendor/postgres-v16
 COPY --chown=nonroot vendor/postgres-v17 vendor/postgres-v17
 COPY --chown=nonroot pgxn pgxn
 COPY --chown=nonroot Makefile Makefile
+COPY --chown=nonroot postgres.mk postgres.mk
 COPY --chown=nonroot scripts/ninstall.sh scripts/ninstall.sh

 ENV BUILD_TYPE=release
--- a/142
+++ b/142
@@ -4,11 +4,14 @@ ROOT_PROJECT_DIR := $(dir $(abspath $(lastword $(MAKEFILE_LIST))))
 # managers.
 POSTGRES_INSTALL_DIR ?= $(ROOT_PROJECT_DIR)/pg_install/

+# Supported PostgreSQL versions
+POSTGRES_VERSIONS = v17 v16 v15 v14
+
 # CARGO_BUILD_FLAGS: Extra flags to pass to `cargo build`. `--locked`
 # and `--features testing` are popular examples.
 #
-# CARGO_PROFILE: You can also set to override the cargo profile to
-# use. By default, it is derived from BUILD_TYPE.
+# CARGO_PROFILE: Set to override the cargo profile to use. By default,
+# it is derived from BUILD_TYPE.

 # All intermediate build artifacts are stored here.
 BUILD_DIR := build
@@ -27,18 +30,11 @@ ifeq ($(BUILD_TYPE),release)
 	PG_CFLAGS += -O2 -g3 $(CFLAGS)
 	PG_LDFLAGS = $(LDFLAGS)
 	CARGO_PROFILE ?= --profile=release
-	# NEON_CARGO_ARTIFACT_TARGET_DIR is the directory where `cargo build` places
-	# the final build artifacts. There is unfortunately no easy way of changing
-	# it to a fully predictable path, nor to extract the path with a simple
-	# command. See https://github.com/rust-lang/cargo/issues/9661 and
-	# https://github.com/rust-lang/cargo/issues/6790.
-	NEON_CARGO_ARTIFACT_TARGET_DIR = $(ROOT_PROJECT_DIR)/target/release
 else ifeq ($(BUILD_TYPE),debug)
 	PG_CONFIGURE_OPTS = --enable-debug --with-openssl --enable-cassert --enable-depend
 	PG_CFLAGS += -O0 -g3 $(CFLAGS)
 	PG_LDFLAGS = $(LDFLAGS)
 	CARGO_PROFILE ?= --profile=dev
-	NEON_CARGO_ARTIFACT_TARGET_DIR = $(ROOT_PROJECT_DIR)/target/debug
 else
 	$(error Bad build type '$(BUILD_TYPE)', see Makefile for options)
 endif
@@ -102,13 +98,13 @@ CACHEDIR_TAG_CONTENTS := "Signature: 8a477f597d28d172789f06886806bc55"
 # Top level Makefile to build Neon and PostgreSQL
 #
 .PHONY: all
-all: neon postgres neon-pg-ext
+all: neon postgres-install neon-pg-ext

 ### Neon Rust bits
 #
 # The 'postgres_ffi' depends on the Postgres headers.
 .PHONY: neon
-neon: postgres-headers walproposer-lib cargo-target-dir
+neon: postgres-headers-install walproposer-lib cargo-target-dir
 	+@echo "Compiling Neon"
 	$(CARGO_CMD_PREFIX) cargo build $(CARGO_BUILD_FLAGS) $(CARGO_PROFILE)

@@ -118,84 +114,11 @@ cargo-target-dir:
 	mkdir -p target
 	test -e target/CACHEDIR.TAG || echo "$(CACHEDIR_TAG_CONTENTS)" > target/CACHEDIR.TAG

-### PostgreSQL parts
-# Some rules are duplicated for Postgres v14 and 15. We may want to refactor
-# to avoid the duplication in the future, but it's tolerable for now.
-#
-$(BUILD_DIR)/%/config.status:
-	mkdir -p $(BUILD_DIR)
-	test -e $(BUILD_DIR)/CACHEDIR.TAG || echo "$(CACHEDIR_TAG_CONTENTS)" > $(BUILD_DIR)/CACHEDIR.TAG
-
-	+@echo "Configuring Postgres $* build"
-	@test -s $(ROOT_PROJECT_DIR)/vendor/postgres-$*/configure || { \
-		echo "\nPostgres submodule not found in $(ROOT_PROJECT_DIR)/vendor/postgres-$*/, execute "; \
-		echo "'git submodule update --init --recursive --depth 2 --progress .' in project root.\n"; \
-		exit 1; }
-	mkdir -p $(BUILD_DIR)/$*
-
-	VERSION=$*; \
-	EXTRA_VERSION=$$(cd $(ROOT_PROJECT_DIR)/vendor/postgres-$$VERSION && git rev-parse HEAD); \
-	(cd $(BUILD_DIR)/$$VERSION && \
-	env PATH="$(EXTRA_PATH_OVERRIDES):$$PATH" $(ROOT_PROJECT_DIR)/vendor/postgres-$$VERSION/configure \
-		CFLAGS='$(PG_CFLAGS)' LDFLAGS='$(PG_LDFLAGS)' \
-		$(PG_CONFIGURE_OPTS) --with-extra-version=" ($$EXTRA_VERSION)" \
-		--prefix=$(abspath $(POSTGRES_INSTALL_DIR))/$$VERSION > configure.log)
-
-# nicer alias to run 'configure'
-# Note: I've been unable to use templates for this part of our configuration.
-# I'm not sure why it wouldn't work, but this is the only place (apart from
-# the "build-all-versions" entry points) where direct mention of PostgreSQL
-# versions is used.
-.PHONY: postgres-configure-v17
-postgres-configure-v17: $(BUILD_DIR)/v17/config.status
-.PHONY: postgres-configure-v16
-postgres-configure-v16: $(BUILD_DIR)/v16/config.status
-.PHONY: postgres-configure-v15
-postgres-configure-v15: $(BUILD_DIR)/v15/config.status
-.PHONY: postgres-configure-v14
-postgres-configure-v14: $(BUILD_DIR)/v14/config.status
-
-# Install the PostgreSQL header files into $(POSTGRES_INSTALL_DIR)/<version>/include
-.PHONY: postgres-headers-%
-postgres-headers-%: postgres-configure-%
-	+@echo "Installing PostgreSQL $* headers"
-	$(MAKE) -C $(BUILD_DIR)/$*/src/include MAKELEVEL=0 install
-
-# Compile and install PostgreSQL
-.PHONY: postgres-%
-postgres-%: postgres-configure-% \
-		  postgres-headers-% # to prevent `make install` conflicts with neon's `postgres-headers`
-	+@echo "Compiling PostgreSQL $*"
-	$(MAKE) -C $(BUILD_DIR)/$* MAKELEVEL=0 install
-	+@echo "Compiling libpq $*"
-	$(MAKE) -C $(BUILD_DIR)/$*/src/interfaces/libpq install
-	+@echo "Compiling pg_prewarm $*"
-	$(MAKE) -C $(BUILD_DIR)/$*/contrib/pg_prewarm install
-	+@echo "Compiling pg_buffercache $*"
-	$(MAKE) -C $(BUILD_DIR)/$*/contrib/pg_buffercache install
-	+@echo "Compiling pg_visibility $*"
-	$(MAKE) -C $(BUILD_DIR)/$*/contrib/pg_visibility install
-	+@echo "Compiling pageinspect $*"
-	$(MAKE) -C $(BUILD_DIR)/$*/contrib/pageinspect install
-	+@echo "Compiling pg_trgm $*"
-	$(MAKE) -C $(BUILD_DIR)/$*/contrib/pg_trgm install
-	+@echo "Compiling amcheck $*"
-	$(MAKE) -C $(BUILD_DIR)/$*/contrib/amcheck install
-	+@echo "Compiling test_decoding $*"
-	$(MAKE) -C $(BUILD_DIR)/$*/contrib/test_decoding install
-
-.PHONY: postgres-check-%
-postgres-check-%: postgres-%
-	$(MAKE) -C $(BUILD_DIR)/$* MAKELEVEL=0 check
-
 .PHONY: neon-pg-ext-%
-neon-pg-ext-%: postgres-% cargo-target-dir
+neon-pg-ext-%: postgres-install-%
 	+@echo "Compiling neon-specific Postgres extensions for $*"
 	mkdir -p $(BUILD_DIR)/pgxn-$*
-	$(MAKE) PG_CONFIG="$(POSTGRES_INSTALL_DIR)/$*/bin/pg_config" COPT='$(COPT)' \
-		NEON_CARGO_ARTIFACT_TARGET_DIR="$(NEON_CARGO_ARTIFACT_TARGET_DIR)" \
-		CARGO_BUILD_FLAGS="$(CARGO_BUILD_FLAGS)" \
-		CARGO_PROFILE="$(CARGO_PROFILE)" \
+	$(MAKE) PG_CONFIG=$(POSTGRES_INSTALL_DIR)/$*/bin/pg_config COPT='$(COPT)' \
 		-C $(BUILD_DIR)/pgxn-$*\
 		-f $(ROOT_PROJECT_DIR)/pgxn/Makefile  install

@@ -231,39 +154,14 @@ ifeq ($(UNAME_S),Linux)
 		pg_crc32c.o
 endif

+# Shorthand to call neon-pg-ext-% target for all Postgres versions
 .PHONY: neon-pg-ext
-neon-pg-ext: \
-	neon-pg-ext-v14 \
-	neon-pg-ext-v15 \
-	neon-pg-ext-v16 \
-	neon-pg-ext-v17
-
-# shorthand to build all Postgres versions
-.PHONY: postgres
-postgres: \
-	postgres-v14 \
-	postgres-v15 \
-	postgres-v16 \
-	postgres-v17
-
-.PHONY: postgres-headers
-postgres-headers: \
-	postgres-headers-v14 \
-	postgres-headers-v15 \
-	postgres-headers-v16 \
-	postgres-headers-v17
-
-.PHONY: postgres-check
-postgres-check: \
-	postgres-check-v14 \
-	postgres-check-v15 \
-	postgres-check-v16 \
-	postgres-check-v17
+neon-pg-ext: $(foreach pg_version,$(POSTGRES_VERSIONS),neon-pg-ext-$(pg_version))

 # This removes everything
 .PHONY: distclean
 distclean:
-	$(RM) -r $(POSTGRES_INSTALL_DIR)
+	$(RM) -r $(POSTGRES_INSTALL_DIR) $(BUILD_DIR)
 	$(CARGO_CMD_PREFIX) cargo clean

 .PHONY: fmt
@@ -311,3 +209,19 @@ neon-pgindent: postgres-v17-pg-bsd-indent neon-pg-ext-v17
 .PHONY: setup-pre-commit-hook
 setup-pre-commit-hook:
 	ln -s -f $(ROOT_PROJECT_DIR)/pre-commit.py .git/hooks/pre-commit
+
+# Targets for building PostgreSQL are defined in postgres.mk.
+#
+# But if the caller has indicated that PostgreSQL is already
+# installed, by setting the PG_INSTALL_CACHED variable, skip it.
+ifdef PG_INSTALL_CACHED
+postgres-install: skip-install
+$(foreach pg_version,$(POSTGRES_VERSIONS),postgres-install-$(pg_version)): skip-install
+postgres-headers-install:
+	+@echo "Skipping installation of PostgreSQL headers because PG_INSTALL_CACHED is set"
+skip-install:
+	+@echo "Skipping PostgreSQL installation because PG_INSTALL_CACHED is set"
+
+else
+include postgres.mk
+endif
--- a/build-tools.Dockerfile
+++ b/build-tools.Dockerfile
@@ -165,6 +165,7 @@ RUN curl -fsSL \
    && rm sql_exporter.tar.gz

 # protobuf-compiler (protoc)
+# Keep the version the same as in compute/compute-node.Dockerfile
 ENV PROTOC_VERSION=25.1
 RUN curl -fsSL "https://github.com/protocolbuffers/protobuf/releases/download/v${PROTOC_VERSION}/protoc-${PROTOC_VERSION}-linux-$(uname -m | sed 's/aarch64/aarch_64/g').zip" -o "protoc.zip" \
    && unzip -q protoc.zip -d protoc \
@@ -179,7 +180,7 @@ RUN curl -sL "https://github.com/peak/s5cmd/releases/download/v${S5CMD_VERSION}/
    && mv s5cmd /usr/local/bin/s5cmd

 # LLVM
-ENV LLVM_VERSION=19
+ENV LLVM_VERSION=20
 RUN curl -fsSL 'https://apt.llvm.org/llvm-snapshot.gpg.key' | apt-key add - \
    && echo "deb http://apt.llvm.org/${DEBIAN_VERSION}/ llvm-toolchain-${DEBIAN_VERSION}-${LLVM_VERSION} main" > /etc/apt/sources.list.d/llvm.stable.list \
    && apt update \
@@ -292,7 +293,7 @@ WORKDIR /home/nonroot

 # Rust
 # Please keep the version of llvm (installed above) in sync with rust llvm (`rustc --version --verbose | grep LLVM`)
-ENV RUSTC_VERSION=1.87.0
+ENV RUSTC_VERSION=1.88.0
 ENV RUSTUP_HOME="/home/nonroot/.rustup"
 ENV PATH="/home/nonroot/.cargo/bin:${PATH}"
 ARG RUSTFILT_VERSION=0.2.1
--- a/compute/Makefile
+++ b/compute/Makefile
@@ -22,7 +22,7 @@ sql_exporter.yml: $(jsonnet_files)
 		--output-file etc/$@ \
 		--tla-str collector_name=neon_collector \
 		--tla-str collector_file=neon_collector.yml \
-		--tla-str 'connection_string=postgresql://cloud_admin@127.0.0.1:5432/postgres?sslmode=disable&application_name=sql_exporter' \
+		--tla-str 'connection_string=postgresql://cloud_admin@127.0.0.1:5432/postgres?sslmode=disable&application_name=sql_exporter&pgaudit.log=none' \
 		etc/sql_exporter.jsonnet

 sql_exporter_autoscaling.yml: $(jsonnet_files)
@@ -30,7 +30,7 @@ sql_exporter_autoscaling.yml: $(jsonnet_files)
 		--output-file etc/$@ \
 		--tla-str collector_name=neon_collector_autoscaling \
 		--tla-str collector_file=neon_collector_autoscaling.yml \
-		--tla-str 'connection_string=postgresql://cloud_admin@127.0.0.1:5432/postgres?sslmode=disable&application_name=sql_exporter_autoscaling' \
+		--tla-str 'connection_string=postgresql://cloud_admin@127.0.0.1:5432/postgres?sslmode=disable&application_name=sql_exporter_autoscaling&pgaudit.log=none' \
 		etc/sql_exporter.jsonnet

 .PHONY: clean
--- a/compute/compute-node.Dockerfile
+++ b/compute/compute-node.Dockerfile
@@ -115,6 +115,9 @@ ARG EXTENSIONS=all
 FROM $BASE_IMAGE_SHA AS build-deps
 ARG DEBIAN_VERSION

+# Keep in sync with build-tools.Dockerfile
+ENV PROTOC_VERSION=25.1
+
 # Use strict mode for bash to catch errors early
 SHELL ["/bin/bash", "-euo", "pipefail", "-c"]

@@ -149,8 +152,14 @@ RUN case $DEBIAN_VERSION in \
    libclang-dev \
    jsonnet \
    $VERSION_INSTALLS \
-    && apt clean && rm -rf /var/lib/apt/lists/* && \
-    useradd -ms /bin/bash nonroot -b /home
+    && apt clean && rm -rf /var/lib/apt/lists/* \
+    && useradd -ms /bin/bash nonroot -b /home \
+    # Install protoc from binary release, since Debian's versions are too old.
+    && curl -fsSL "https://github.com/protocolbuffers/protobuf/releases/download/v${PROTOC_VERSION}/protoc-${PROTOC_VERSION}-linux-$(uname -m | sed 's/aarch64/aarch_64/g').zip" -o "protoc.zip" \
+    && unzip -q protoc.zip -d protoc \
+    && mv protoc/bin/protoc /usr/local/bin/protoc \
+    && mv protoc/include/google /usr/local/include/google \
+    && rm -rf protoc.zip protoc

 #########################################################################################
 #
@@ -171,9 +180,6 @@ RUN cd postgres && \
    eval $CONFIGURE_CMD && \
    make MAKELEVEL=0 -j $(getconf _NPROCESSORS_ONLN) -s install && \
    make MAKELEVEL=0 -j $(getconf _NPROCESSORS_ONLN) -s -C contrib/ install && \
-    # Install headers
-    make MAKELEVEL=0 -j $(getconf _NPROCESSORS_ONLN) -s -C src/include install && \
-    make MAKELEVEL=0 -j $(getconf _NPROCESSORS_ONLN) -s -C src/interfaces/libpq install && \
    # Enable some of contrib extensions
    echo 'trusted = true' >> /usr/local/pgsql/share/extension/autoinc.control && \
    echo 'trusted = true' >> /usr/local/pgsql/share/extension/dblink.control && \
@@ -1173,7 +1179,7 @@ COPY --from=pgrag-src /ext-src/ /ext-src/
 # Install it using virtual environment, because Python 3.11 (the default version on Debian 12 (Bookworm)) complains otherwise
 WORKDIR /ext-src/onnxruntime-src
 RUN apt update && apt install --no-install-recommends --no-install-suggests -y \
-    python3 python3-pip python3-venv protobuf-compiler && \
+    python3 python3-pip python3-venv && \
    apt clean && rm -rf /var/lib/apt/lists/* && \
    python3 -m venv venv && \
    . venv/bin/activate && \
@@ -1568,20 +1574,20 @@ ARG PG_VERSION
 WORKDIR /ext-src
 RUN case "${PG_VERSION}" in \
    "v14") \
-    export PGAUDIT_VERSION=1.6.2 \
-    export PGAUDIT_CHECKSUM=1f350d70a0cbf488c0f2b485e3a5c9b11f78ad9e3cbb95ef6904afa1eb3187eb \
+    export PGAUDIT_VERSION=1.6.3 \
+    export PGAUDIT_CHECKSUM=37a8f5a7cc8d9188e536d15cf0fdc457fcdab2547caedb54442c37f124110919 \
    ;; \
    "v15") \
-    export PGAUDIT_VERSION=1.7.0 \
-    export PGAUDIT_CHECKSUM=8f4a73e451c88c567e516e6cba7dc1e23bc91686bb6f1f77f8f3126d428a8bd8 \
+    export PGAUDIT_VERSION=1.7.1 \
+    export PGAUDIT_CHECKSUM=e9c8e6e092d82b2f901d72555ce0fe7780552f35f8985573796cd7e64b09d4ec \
    ;; \
    "v16") \
-    export PGAUDIT_VERSION=16.0 \
-    export PGAUDIT_CHECKSUM=d53ef985f2d0b15ba25c512c4ce967dce07b94fd4422c95bd04c4c1a055fe738 \
+    export PGAUDIT_VERSION=16.1 \
+    export PGAUDIT_CHECKSUM=3bae908ab70ba0c6f51224009dbcfff1a97bd6104c6273297a64292e1b921fee \
    ;; \
    "v17") \
-    export PGAUDIT_VERSION=17.0 \
-    export PGAUDIT_CHECKSUM=7d0d08d030275d525f36cd48b38c6455f1023da863385badff0cec44965bfd8c \
+    export PGAUDIT_VERSION=17.1 \
+    export PGAUDIT_CHECKSUM=9c5f37504d393486cc75d2ced83f75f5899be64fa85f689d6babb833b4361e6c \
    ;; \
    *) \
    echo "pgaudit is not supported on this PostgreSQL version" && exit 1;; \
--- a/compute/vm-image-spec-bookworm.yaml
+++ b/compute/vm-image-spec-bookworm.yaml
@@ -26,7 +26,7 @@ commands:
  - name: postgres-exporter
    user: nobody
    sysvInitAction: respawn
-    shell: 'DATA_SOURCE_NAME="user=cloud_admin sslmode=disable dbname=postgres application_name=postgres-exporter" /bin/postgres_exporter --config.file=/etc/postgres_exporter.yml'
+    shell: 'DATA_SOURCE_NAME="user=cloud_admin sslmode=disable dbname=postgres application_name=postgres-exporter pgaudit.log=none" /bin/postgres_exporter --config.file=/etc/postgres_exporter.yml'
  - name: pgbouncer-exporter
    user: postgres
    sysvInitAction: respawn
@@ -59,7 +59,7 @@ files:
      # the rules use ALL as the hostname. Avoid the pointless lookups and the "unable to
      # resolve host" log messages that they generate.
      Defaults !fqdn
-      
+
      # Allow postgres user (which is what compute_ctl runs as) to run /neonvm/bin/resize-swap
      # and /neonvm/bin/set-disk-quota as root without requiring entering a password (NOPASSWD),
      # regardless of hostname (ALL)
--- a/compute/vm-image-spec-bullseye.yaml
+++ b/compute/vm-image-spec-bullseye.yaml
@@ -26,7 +26,7 @@ commands:
  - name: postgres-exporter
    user: nobody
    sysvInitAction: respawn
-    shell: 'DATA_SOURCE_NAME="user=cloud_admin sslmode=disable dbname=postgres application_name=postgres-exporter" /bin/postgres_exporter --config.file=/etc/postgres_exporter.yml'
+    shell: 'DATA_SOURCE_NAME="user=cloud_admin sslmode=disable dbname=postgres application_name=postgres-exporter pgaudit.log=none" /bin/postgres_exporter --config.file=/etc/postgres_exporter.yml'
  - name: pgbouncer-exporter
    user: postgres
    sysvInitAction: respawn
@@ -59,7 +59,7 @@ files:
      # the rules use ALL as the hostname. Avoid the pointless lookups and the "unable to
      # resolve host" log messages that they generate.
      Defaults !fqdn
-      
+
      # Allow postgres user (which is what compute_ctl runs as) to run /neonvm/bin/resize-swap
      # and /neonvm/bin/set-disk-quota as root without requiring entering a password (NOPASSWD),
      # regardless of hostname (ALL)
--- a/compute_tools/Cargo.toml
+++ b/compute_tools/Cargo.toml
@@ -66,6 +66,7 @@ uuid.workspace = true
 walkdir.workspace = true
 x509-cert.workspace = true

+postgres_versioninfo.workspace = true
 postgres_initdb.workspace = true
 compute_api.workspace = true
 utils.workspace = true
--- a/compute_tools/src/bin/compute_ctl.rs
+++ b/compute_tools/src/bin/compute_ctl.rs
@@ -36,6 +36,8 @@
 use std::ffi::OsString;
 use std::fs::File;
 use std::process::exit;
+use std::sync::Arc;
+use std::sync::atomic::AtomicU64;
 use std::sync::mpsc;
 use std::thread;
 use std::time::Duration;
@@ -190,7 +192,9 @@ fn main() -> Result<()> {
            cgroup: cli.cgroup,
            #[cfg(target_os = "linux")]
            vm_monitor_addr: cli.vm_monitor_addr,
-            installed_extensions_collection_interval: cli.installed_extensions_collection_interval,
+            installed_extensions_collection_interval: Arc::new(AtomicU64::new(
+                cli.installed_extensions_collection_interval,
+            )),
        },
        config,
    )?;
--- a/compute_tools/src/bin/fast_import.rs
+++ b/compute_tools/src/bin/fast_import.rs
@@ -29,7 +29,7 @@ use anyhow::{Context, bail};
 use aws_config::BehaviorVersion;
 use camino::{Utf8Path, Utf8PathBuf};
 use clap::{Parser, Subcommand};
-use compute_tools::extension_server::{PostgresMajorVersion, get_pg_version};
+use compute_tools::extension_server::get_pg_version;
 use nix::unistd::Pid;
 use std::ops::Not;
 use tracing::{Instrument, error, info, info_span, warn};
@@ -179,12 +179,8 @@ impl PostgresProcess {
            .await
            .context("create pgdata directory")?;

-        let pg_version = match get_pg_version(self.pgbin.as_ref()) {
-            PostgresMajorVersion::V14 => 14,
-            PostgresMajorVersion::V15 => 15,
-            PostgresMajorVersion::V16 => 16,
-            PostgresMajorVersion::V17 => 17,
-        };
+        let pg_version = get_pg_version(self.pgbin.as_ref());
+
        postgres_initdb::do_run_initdb(postgres_initdb::RunInitdbArgs {
            superuser: initdb_user,
            locale: DEFAULT_LOCALE, // XXX: this shouldn't be hard-coded,
@@ -486,10 +482,8 @@ async fn cmd_pgdata(
    };

    let superuser = "cloud_admin";
-    let destination_connstring = format!(
-        "host=localhost port={} user={} dbname=neondb",
-        pg_port, superuser
-    );
+    let destination_connstring =
+        format!("host=localhost port={pg_port} user={superuser} dbname=neondb");

    let pgdata_dir = workdir.join("pgdata");
    let mut proc = PostgresProcess::new(pgdata_dir.clone(), pg_bin_dir.clone(), pg_lib_dir.clone());
--- a/compute_tools/src/bin/fast_import/s3_uri.rs
+++ b/compute_tools/src/bin/fast_import/s3_uri.rs
@@ -69,7 +69,7 @@ impl clap::builder::TypedValueParser for S3Uri {
        S3Uri::from_str(value_str).map_err(|e| {
            clap::Error::raw(
                clap::error::ErrorKind::InvalidValue,
-                format!("Failed to parse S3 URI: {}", e),
+                format!("Failed to parse S3 URI: {e}"),
            )
        })
    }
--- a/compute_tools/src/catalog.rs
+++ b/compute_tools/src/catalog.rs
@@ -22,7 +22,7 @@ pub async fn get_dbs_and_roles(compute: &Arc<ComputeNode>) -> anyhow::Result<Cat

    spawn(async move {
        if let Err(e) = connection.await {
-            eprintln!("connection error: {}", e);
+            eprintln!("connection error: {e}");
        }
    });

@@ -119,7 +119,7 @@ pub async fn get_database_schema(
        _ => {
            let mut lines = stderr_reader.lines();
            if let Some(line) = lines.next_line().await? {
-                if line.contains(&format!("FATAL:  database \"{}\" does not exist", dbname)) {
+                if line.contains(&format!("FATAL:  database \"{dbname}\" does not exist")) {
                    return Err(SchemaDumpError::DatabaseDoesNotExist);
                }
                warn!("pg_dump stderr: {}", line)
--- a/compute_tools/src/compute.rs
+++ b/compute_tools/src/compute.rs
@@ -1,4 +1,4 @@
-use anyhow::{Context, Result, anyhow};
+use anyhow::{Context, Result};
 use chrono::{DateTime, Utc};
 use compute_api::privilege::Privilege;
 use compute_api::responses::{
@@ -6,7 +6,7 @@ use compute_api::responses::{
    LfcPrewarmState, TlsConfig,
 };
 use compute_api::spec::{
-    ComputeAudit, ComputeFeature, ComputeMode, ComputeSpec, ExtVersion, PgIdent,
+    ComputeAudit, ComputeFeature, ComputeMode, ComputeSpec, ExtVersion, PageserverProtocol, PgIdent,
 };
 use futures::StreamExt;
 use futures::future::join_all;
@@ -15,29 +15,28 @@ use itertools::Itertools;
 use nix::sys::signal::{Signal, kill};
 use nix::unistd::Pid;
 use once_cell::sync::Lazy;
-use pageserver_page_api as page_api;
+use pageserver_page_api::{self as page_api, BaseBackupCompression};
 use postgres;
 use postgres::NoTls;
 use postgres::error::SqlState;
 use remote_storage::{DownloadError, RemotePath};
 use std::collections::{HashMap, HashSet};
-use std::net::SocketAddr;
 use std::os::unix::fs::{PermissionsExt, symlink};
 use std::path::Path;
 use std::process::{Command, Stdio};
 use std::str::FromStr;
-use std::sync::atomic::{AtomicU32, Ordering};
+use std::sync::atomic::{AtomicU32, AtomicU64, Ordering};
 use std::sync::{Arc, Condvar, Mutex, RwLock};
 use std::time::{Duration, Instant};
 use std::{env, fs};
 use tokio::spawn;
-use tokio_util::io::StreamReader;
 use tracing::{Instrument, debug, error, info, instrument, warn};
 use url::Url;
 use utils::id::{TenantId, TimelineId};
 use utils::lsn::Lsn;
 use utils::measured_stream::MeasuredReader;
 use utils::pid_file;
+use utils::shard::{ShardCount, ShardIndex, ShardNumber};

 use crate::configurator::launch_configurator;
 use crate::disk_quota::set_disk_quota;
@@ -71,6 +70,7 @@ pub static BUILD_TAG: Lazy<String> = Lazy::new(|| {
        .unwrap_or(BUILD_TAG_DEFAULT)
        .to_string()
 });
+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.
@@ -104,7 +104,7 @@ pub struct ComputeNodeParams {
    pub remote_ext_base_url: Option<Url>,

    /// Interval for installed extensions collection
-    pub installed_extensions_collection_interval: u64,
+    pub installed_extensions_collection_interval: Arc<AtomicU64>,
 }

 /// Compute node info shared across several `compute_ctl` threads.
@@ -127,6 +127,9 @@ pub struct ComputeNode {
    // key: ext_archive_name, value: started download time, download_completed?
    pub ext_download_progress: RwLock<HashMap<String, (DateTime<Utc>, bool)>>,
    pub compute_ctl_config: ComputeCtlConfig,
+
+    /// Handle to the extension stats collection task
+    extension_stats_task: Mutex<Option<tokio::task::JoinHandle<()>>>,
 }

 // store some metrics about download size that might impact startup time
@@ -220,7 +223,8 @@ pub struct ParsedSpec {
    pub pageserver_connstr: String,
    pub safekeeper_connstrings: Vec<String>,
    pub storage_auth_token: Option<String>,
-    pub endpoint_storage_addr: Option<SocketAddr>,
+    /// k8s dns name and port
+    pub endpoint_storage_addr: Option<String>,
    pub endpoint_storage_token: Option<String>,
 }

@@ -252,8 +256,7 @@ impl ParsedSpec {
            // duplicate entry?
            if current == previous {
                return Err(format!(
-                    "duplicate entry in safekeeper_connstrings: {}!",
-                    current,
+                    "duplicate entry in safekeeper_connstrings: {current}!",
                ));
            }

@@ -316,13 +319,10 @@ impl TryFrom<ComputeSpec> for ParsedSpec {
                .or(Err("invalid timeline id"))?
        };

-        let endpoint_storage_addr: Option<SocketAddr> = spec
+        let endpoint_storage_addr: Option<String> = spec
            .endpoint_storage_addr
            .clone()
-            .or_else(|| spec.cluster.settings.find("neon.endpoint_storage_addr"))
-            .unwrap_or_default()
-            .parse()
-            .ok();
+            .or_else(|| spec.cluster.settings.find("neon.endpoint_storage_addr"));
        let endpoint_storage_token = spec
            .endpoint_storage_token
            .clone()
@@ -408,11 +408,11 @@ impl ComputeNode {
        // that can affect `compute_ctl` and prevent it from properly configuring the database schema.
        // Unset them via connection string options before connecting to the database.
        // N.B. keep it in sync with `ZENITH_OPTIONS` in `get_maintenance_client()`.
-        const EXTRA_OPTIONS: &str = "-c role=cloud_admin -c default_transaction_read_only=off -c search_path=public -c statement_timeout=0";
+        const EXTRA_OPTIONS: &str = "-c role=cloud_admin -c default_transaction_read_only=off -c search_path=public -c statement_timeout=0 -c pgaudit.log=none";
        let options = match conn_conf.get_options() {
            // Allow the control plane to override any options set by the
            // compute
-            Some(options) => format!("{} {}", EXTRA_OPTIONS, options),
+            Some(options) => format!("{EXTRA_OPTIONS} {options}"),
            None => EXTRA_OPTIONS.to_string(),
        };
        conn_conf.options(&options);
@@ -420,7 +420,7 @@ impl ComputeNode {

        let mut new_state = ComputeState::new();
        if let Some(spec) = config.spec {
-            let pspec = ParsedSpec::try_from(spec).map_err(|msg| anyhow!(msg))?;
+            let pspec = ParsedSpec::try_from(spec).map_err(|msg| anyhow::anyhow!(msg))?;
            new_state.pspec = Some(pspec);
        }

@@ -432,6 +432,7 @@ impl ComputeNode {
            state_changed: Condvar::new(),
            ext_download_progress: RwLock::new(HashMap::new()),
            compute_ctl_config: config.compute_ctl_config,
+            extension_stats_task: Mutex::new(None),
        })
    }

@@ -519,6 +520,9 @@ impl ComputeNode {
            None
        };

+        // Terminate the extension stats collection task
+        this.terminate_extension_stats_task();
+
        // Terminate the vm_monitor so it releases the file watcher on
        // /sys/fs/cgroup/neon-postgres.
        // Note: the vm-monitor only runs on linux because it requires cgroups.
@@ -1001,82 +1005,80 @@ impl ComputeNode {
        Ok(())
    }

-    // Get basebackup from the libpq connection to pageserver using `connstr` and
-    // unarchive it to `pgdata` directory overriding all its previous content.
+    /// Fetches a basebackup from the Pageserver using the compute state's Pageserver connstring and
+    /// unarchives it to `pgdata` directory, replacing any existing contents.
    #[instrument(skip_all, fields(%lsn))]
    fn try_get_basebackup(&self, compute_state: &ComputeState, lsn: Lsn) -> Result<()> {
        let spec = compute_state.pspec.as_ref().expect("spec must be set");
-        let shard0_connstr = spec.pageserver_connstr.split(',').next().unwrap();

-        match Url::parse(shard0_connstr)?.scheme() {
-            "postgres" | "postgresql" => self.try_get_basebackup_libpq(spec, lsn),
-            "grpc" => self.try_get_basebackup_grpc(spec, lsn),
-            scheme => return Err(anyhow!("unknown URL scheme {scheme}")),
-        }
+        let shard0_connstr = spec.pageserver_connstr.split(',').next().unwrap();
+        let started = Instant::now();
+
+        let (connected, size) = match PageserverProtocol::from_connstring(shard0_connstr)? {
+            PageserverProtocol::Libpq => self.try_get_basebackup_libpq(spec, lsn)?,
+            PageserverProtocol::Grpc => self.try_get_basebackup_grpc(spec, lsn)?,
+        };
+
+        let mut state = self.state.lock().unwrap();
+        state.metrics.pageserver_connect_micros =
+            connected.duration_since(started).as_micros() as u64;
+        state.metrics.basebackup_bytes = size as u64;
+        state.metrics.basebackup_ms = started.elapsed().as_millis() as u64;
+
+        Ok(())
    }

-    fn try_get_basebackup_grpc(&self, spec: &ParsedSpec, lsn: Lsn) -> Result<()> {
-        let start_time = Instant::now();
-
+    /// Fetches a basebackup via gRPC. The connstring must use grpc://. Returns the timestamp when
+    /// the connection was established, and the (compressed) size of the basebackup.
+    fn try_get_basebackup_grpc(&self, spec: &ParsedSpec, lsn: Lsn) -> Result<(Instant, usize)> {
        let shard0_connstr = spec
            .pageserver_connstr
            .split(',')
            .next()
            .unwrap()
            .to_string();
+        let shard_index = match spec.pageserver_connstr.split(',').count() as u8 {
+            0 | 1 => ShardIndex::unsharded(),
+            count => ShardIndex::new(ShardNumber(0), ShardCount(count)),
+        };

-        let chunks = tokio::runtime::Handle::current().block_on(async move {
-            let mut client = page_api::proto::PageServiceClient::connect(shard0_connstr).await?;
-
-            let req = page_api::proto::GetBaseBackupRequest {
-                lsn: lsn.0,
-                replica: false, // TODO: handle replicas, with LSN 0
-                full: false,
-            };
-            let mut req = tonic::Request::new(req);
-            let metadata = req.metadata_mut();
-            metadata.insert("neon-tenant-id", spec.tenant_id.to_string().parse()?);
-            metadata.insert("neon-timeline-id", spec.timeline_id.to_string().parse()?);
-            metadata.insert("neon-shard-id", "0000".to_string().parse()?); // TODO: shard count
-            if let Some(auth) = spec.storage_auth_token.as_ref() {
-                metadata.insert("authorization", format!("Bearer {auth}").parse()?);
-            }
-
-            let chunks = client.get_base_backup(req).await?.into_inner();
-            anyhow::Ok(chunks)
+        let (reader, connected) = tokio::runtime::Handle::current().block_on(async move {
+            let mut client = page_api::Client::new(
+                shard0_connstr,
+                spec.tenant_id,
+                spec.timeline_id,
+                shard_index,
+                spec.storage_auth_token.clone(),
+                None, // NB: base backups use payload compression
+            )
+            .await?;
+            let connected = Instant::now();
+            let reader = client
+                .get_base_backup(page_api::GetBaseBackupRequest {
+                    lsn: (lsn != Lsn(0)).then_some(lsn),
+                    compression: BaseBackupCompression::Gzip,
+                    replica: spec.spec.mode != ComputeMode::Primary,
+                    full: false,
+                })
+                .await?;
+            anyhow::Ok((reader, connected))
        })?;
-        let pageserver_connect_micros = start_time.elapsed().as_micros() as u64;

-        // Convert the chunks stream into an AsyncRead
-        let stream_reader = StreamReader::new(
-            chunks.map(|chunk| chunk.map(|c| c.chunk).map_err(std::io::Error::other)),
-        );
+        let mut reader = MeasuredReader::new(tokio_util::io::SyncIoBridge::new(reader));

-        // Wrap the AsyncRead into a blocking reader for compatibility with tar::Archive
-        let reader = tokio_util::io::SyncIoBridge::new(stream_reader);
-        let mut measured_reader = MeasuredReader::new(reader);
-        let mut bufreader = std::io::BufReader::new(&mut measured_reader);
-
-        // Read the archive directly from the `CopyOutReader`
-        //
-        // Set `ignore_zeros` so that unpack() reads all the Copy data and
-        // doesn't stop at the end-of-archive marker. Otherwise, if the server
-        // sends an Error after finishing the tarball, we will not notice it.
-        let mut ar = tar::Archive::new(&mut bufreader);
+        // Set `ignore_zeros` so that unpack() reads the entire stream and doesn't just stop at the
+        // end-of-archive marker. If the server errors, the tar::Builder drop handler will write an
+        // end-of-archive marker before the error is emitted, and we would not see the error.
+        let mut ar = tar::Archive::new(flate2::read::GzDecoder::new(&mut reader));
        ar.set_ignore_zeros(true);
        ar.unpack(&self.params.pgdata)?;

-        // Report metrics
-        let mut state = self.state.lock().unwrap();
-        state.metrics.pageserver_connect_micros = pageserver_connect_micros;
-        state.metrics.basebackup_bytes = measured_reader.get_byte_count() as u64;
-        state.metrics.basebackup_ms = start_time.elapsed().as_millis() as u64;
-        Ok(())
+        Ok((connected, reader.get_byte_count()))
    }

-    fn try_get_basebackup_libpq(&self, spec: &ParsedSpec, lsn: Lsn) -> Result<()> {
-        let start_time = Instant::now();
-
+    /// Fetches a basebackup via libpq. The connstring must use postgresql://. Returns the timestamp
+    /// when the connection was established, and the (compressed) size of the basebackup.
+    fn try_get_basebackup_libpq(&self, spec: &ParsedSpec, lsn: Lsn) -> Result<(Instant, usize)> {
        let shard0_connstr = spec.pageserver_connstr.split(',').next().unwrap();
        let mut config = postgres::Config::from_str(shard0_connstr)?;

@@ -1097,7 +1099,7 @@ impl ComputeNode {

        // Connect to pageserver
        let mut client = config.connect(NoTls)?;
-        let pageserver_connect_micros = start_time.elapsed().as_micros() as u64;
+        let connected = Instant::now();

        let basebackup_cmd = match lsn {
            Lsn(0) => {
@@ -1134,16 +1136,13 @@ impl ComputeNode {
        // Set `ignore_zeros` so that unpack() reads all the Copy data and
        // doesn't stop at the end-of-archive marker. Otherwise, if the server
        // sends an Error after finishing the tarball, we will not notice it.
+        // The tar::Builder drop handler will write an end-of-archive marker
+        // before emitting the error, and we would not see it otherwise.
        let mut ar = tar::Archive::new(flate2::read::GzDecoder::new(&mut bufreader));
        ar.set_ignore_zeros(true);
        ar.unpack(&self.params.pgdata)?;

-        // Report metrics
-        let mut state = self.state.lock().unwrap();
-        state.metrics.pageserver_connect_micros = pageserver_connect_micros;
-        state.metrics.basebackup_bytes = measured_reader.get_byte_count() as u64;
-        state.metrics.basebackup_ms = start_time.elapsed().as_millis() as u64;
-        Ok(())
+        Ok((connected, measured_reader.get_byte_count()))
    }

    // Gets the basebackup in a retry loop
@@ -1167,7 +1166,10 @@ impl ComputeNode {
                    return result;
                }
                Err(ref e) if attempts < max_attempts => {
-                    warn!("Failed to get basebackup: {e:?} (attempt {attempts}/{max_attempts})");
+                    warn!(
+                        "Failed to get basebackup: {} (attempt {}/{})",
+                        e, attempts, max_attempts
+                    );
                    std::thread::sleep(std::time::Duration::from_millis(retry_period_ms as u64));
                    retry_period_ms *= 1.5;
                }
@@ -1193,7 +1195,7 @@ impl ComputeNode {
        let sk_configs = sk_connstrs.into_iter().map(|connstr| {
            // Format connstr
            let id = connstr.clone();
-            let connstr = format!("postgresql://no_user@{}", connstr);
+            let connstr = format!("postgresql://no_user@{connstr}");
            let options = format!(
                "-c timeline_id={} tenant_id={}",
                pspec.timeline_id, pspec.tenant_id
@@ -1556,7 +1558,7 @@ impl ComputeNode {
                let (mut client, connection) = conf.connect(NoTls).await?;
                tokio::spawn(async move {
                    if let Err(e) = connection.await {
-                        eprintln!("connection error: {}", e);
+                        eprintln!("connection error: {e}");
                    }
                });

@@ -1677,6 +1679,8 @@ impl ComputeNode {
            tls_config = self.compute_ctl_config.tls.clone();
        }

+        self.update_installed_extensions_collection_interval(&spec);
+
        let max_concurrent_connections = self.max_service_connections(compute_state, &spec);

        // Merge-apply spec & changes to PostgreSQL state.
@@ -1699,7 +1703,7 @@ impl ComputeNode {
                Ok((mut client, connection)) => {
                    tokio::spawn(async move {
                        if let Err(e) = connection.await {
-                            eprintln!("connection error: {}", e);
+                            eprintln!("connection error: {e}");
                        }
                    });
                    if let Err(e) = handle_migrations(&mut client).await {
@@ -1741,6 +1745,8 @@ impl ComputeNode {

        let tls_config = self.tls_config(&spec);

+        self.update_installed_extensions_collection_interval(&spec);
+
        if let Some(ref pgbouncer_settings) = spec.pgbouncer_settings {
            info!("tuning pgbouncer");

@@ -2003,7 +2009,7 @@ impl ComputeNode {
        let (client, connection) = connect_result.unwrap();
        tokio::spawn(async move {
            if let Err(e) = connection.await {
-                eprintln!("connection error: {}", e);
+                eprintln!("connection error: {e}");
            }
        });
        let result = client
@@ -2045,7 +2051,7 @@ LIMIT 100",
            self.params
                .remote_ext_base_url
                .as_ref()
-                .ok_or(DownloadError::BadInput(anyhow!(
+                .ok_or(DownloadError::BadInput(anyhow::anyhow!(
                    "Remote extensions storage is not configured",
                )))?;

@@ -2172,7 +2178,7 @@ LIMIT 100",
            db_client
                .simple_query(&query)
                .await
-                .with_context(|| format!("Failed to execute query: {}", query))?;
+                .with_context(|| format!("Failed to execute query: {query}"))?;
        }

        Ok(())
@@ -2199,7 +2205,7 @@ LIMIT 100",
        let version: Option<ExtVersion> = db_client
            .query_opt(version_query, &[&ext_name])
            .await
-            .with_context(|| format!("Failed to execute query: {}", version_query))?
+            .with_context(|| format!("Failed to execute query: {version_query}"))?
            .map(|row| row.get(0));

        // sanitize the inputs as postgres idents.
@@ -2214,14 +2220,14 @@ LIMIT 100",
            db_client
                .simple_query(&query)
                .await
-                .with_context(|| format!("Failed to execute query: {}", query))?;
+                .with_context(|| format!("Failed to execute query: {query}"))?;
        } else {
            let query =
                format!("CREATE EXTENSION IF NOT EXISTS {ext_name} WITH VERSION {quoted_version}");
            db_client
                .simple_query(&query)
                .await
-                .with_context(|| format!("Failed to execute query: {}", query))?;
+                .with_context(|| format!("Failed to execute query: {query}"))?;
        }

        Ok(ext_version)
@@ -2241,7 +2247,7 @@ LIMIT 100",
        let remote_extensions = spec
            .remote_extensions
            .as_ref()
-            .ok_or(anyhow!("Remote extensions are not configured"))?;
+            .ok_or(anyhow::anyhow!("Remote extensions are not configured"))?;

        info!("parse shared_preload_libraries from spec.cluster.settings");
        let mut libs_vec = Vec::new();
@@ -2345,10 +2351,20 @@ LIMIT 100",
    }

    pub fn spawn_extension_stats_task(&self) {
+        // Cancel any existing task
+        if let Some(handle) = self.extension_stats_task.lock().unwrap().take() {
+            handle.abort();
+        }
+
        let conf = self.tokio_conn_conf.clone();
-        let installed_extensions_collection_interval =
-            self.params.installed_extensions_collection_interval;
-        tokio::spawn(async move {
+        let atomic_interval = self.params.installed_extensions_collection_interval.clone();
+        let mut installed_extensions_collection_interval =
+            2 * atomic_interval.load(std::sync::atomic::Ordering::SeqCst);
+        info!(
+            "[NEON_EXT_SPAWN] Spawning background installed extensions worker with Timeout: {}",
+            installed_extensions_collection_interval
+        );
+        let handle = tokio::spawn(async move {
            // An initial sleep is added to ensure that two collections don't happen at the same time.
            // The first collection happens during compute startup.
            tokio::time::sleep(tokio::time::Duration::from_secs(
@@ -2361,8 +2377,48 @@ LIMIT 100",
            loop {
                interval.tick().await;
                let _ = installed_extensions(conf.clone()).await;
+                // Acquire a read lock on the compute spec and then update the interval if necessary
+                interval = tokio::time::interval(tokio::time::Duration::from_secs(std::cmp::max(
+                    installed_extensions_collection_interval,
+                    2 * atomic_interval.load(std::sync::atomic::Ordering::SeqCst),
+                )));
+                installed_extensions_collection_interval = interval.period().as_secs();
            }
        });
+
+        // Store the new task handle
+        *self.extension_stats_task.lock().unwrap() = Some(handle);
+    }
+
+    fn terminate_extension_stats_task(&self) {
+        if let Some(handle) = self.extension_stats_task.lock().unwrap().take() {
+            handle.abort();
+        }
+    }
+
+    fn update_installed_extensions_collection_interval(&self, spec: &ComputeSpec) {
+        // Update the interval for collecting installed extensions statistics
+        // If the value is -1, we never suspend so set the value to default collection.
+        // If the value is 0, it means default, we will just continue to use the default.
+        if spec.suspend_timeout_seconds == -1 || spec.suspend_timeout_seconds == 0 {
+            info!(
+                "[NEON_EXT_INT_UPD] Spec Timeout: {}, New Timeout: {}",
+                spec.suspend_timeout_seconds, DEFAULT_INSTALLED_EXTENSIONS_COLLECTION_INTERVAL
+            );
+            self.params.installed_extensions_collection_interval.store(
+                DEFAULT_INSTALLED_EXTENSIONS_COLLECTION_INTERVAL,
+                std::sync::atomic::Ordering::SeqCst,
+            );
+        } else {
+            info!(
+                "[NEON_EXT_INT_UPD] Spec Timeout: {}",
+                spec.suspend_timeout_seconds
+            );
+            self.params.installed_extensions_collection_interval.store(
+                spec.suspend_timeout_seconds as u64,
+                std::sync::atomic::Ordering::SeqCst,
+            );
+        }
    }
 }

--- a/compute_tools/src/config.rs
+++ b/compute_tools/src/config.rs
@@ -51,7 +51,7 @@ pub fn write_postgres_conf(

    // Write the postgresql.conf content from the spec file as is.
    if let Some(conf) = &spec.cluster.postgresql_conf {
-        writeln!(file, "{}", conf)?;
+        writeln!(file, "{conf}")?;
    }

    // Add options for connecting to storage
@@ -70,7 +70,7 @@ pub fn write_postgres_conf(
        );
        // If generation is given, prepend sk list with g#number:
        if let Some(generation) = spec.safekeepers_generation {
-            write!(neon_safekeepers_value, "g#{}:", generation)?;
+            write!(neon_safekeepers_value, "g#{generation}:")?;
        }
        neon_safekeepers_value.push_str(&spec.safekeeper_connstrings.join(","));
        writeln!(
@@ -109,8 +109,8 @@ pub fn write_postgres_conf(
        tls::update_key_path_blocking(pgdata_path, tls_config);

        // these are the default, but good to be explicit.
-        writeln!(file, "ssl_cert_file = '{}'", SERVER_CRT)?;
-        writeln!(file, "ssl_key_file = '{}'", SERVER_KEY)?;
+        writeln!(file, "ssl_cert_file = '{SERVER_CRT}'")?;
+        writeln!(file, "ssl_key_file = '{SERVER_KEY}'")?;
    }

    // Locales
@@ -191,8 +191,7 @@ pub fn write_postgres_conf(
                }
                writeln!(
                    file,
-                    "shared_preload_libraries='{}{}'",
-                    libs, extra_shared_preload_libraries
+                    "shared_preload_libraries='{libs}{extra_shared_preload_libraries}'"
                )?;
            } else {
                // Typically, this should be unreacheable,
@@ -244,8 +243,7 @@ pub fn write_postgres_conf(
                }
                writeln!(
                    file,
-                    "shared_preload_libraries='{}{}'",
-                    libs, extra_shared_preload_libraries
+                    "shared_preload_libraries='{libs}{extra_shared_preload_libraries}'"
                )?;
            } else {
                // Typically, this should be unreacheable,
@@ -263,7 +261,7 @@ pub fn write_postgres_conf(
        }
    }

-    writeln!(file, "neon.extension_server_port={}", extension_server_port)?;
+    writeln!(file, "neon.extension_server_port={extension_server_port}")?;

    if spec.drop_subscriptions_before_start {
        writeln!(file, "neon.disable_logical_replication_subscribers=true")?;
@@ -291,7 +289,7 @@ where
 {
    let path = pgdata_path.join("compute_ctl_temp_override.conf");
    let mut file = File::create(path)?;
-    write!(file, "{}", options)?;
+    write!(file, "{options}")?;

    let res = exec();

--- a/compute_tools/src/extension_server.rs
+++ b/compute_tools/src/extension_server.rs
@@ -74,9 +74,11 @@ More specifically, here is an example ext_index.json
 use std::path::Path;
 use std::str;

+use crate::metrics::{REMOTE_EXT_REQUESTS_TOTAL, UNKNOWN_HTTP_STATUS};
 use anyhow::{Context, Result, bail};
 use bytes::Bytes;
 use compute_api::spec::RemoteExtSpec;
+use postgres_versioninfo::PgMajorVersion;
 use regex::Regex;
 use remote_storage::*;
 use reqwest::StatusCode;
@@ -86,8 +88,6 @@ use tracing::log::warn;
 use url::Url;
 use zstd::stream::read::Decoder;

-use crate::metrics::{REMOTE_EXT_REQUESTS_TOTAL, UNKNOWN_HTTP_STATUS};
-
 fn get_pg_config(argument: &str, pgbin: &str) -> String {
    // gives the result of `pg_config [argument]`
    // where argument is a flag like `--version` or `--sharedir`
@@ -106,7 +106,7 @@ fn get_pg_config(argument: &str, pgbin: &str) -> String {
        .to_string()
 }

-pub fn get_pg_version(pgbin: &str) -> PostgresMajorVersion {
+pub fn get_pg_version(pgbin: &str) -> PgMajorVersion {
    // pg_config --version returns a (platform specific) human readable string
    // such as "PostgreSQL 15.4". We parse this to v14/v15/v16 etc.
    let human_version = get_pg_config("--version", pgbin);
@@ -114,25 +114,11 @@ pub fn get_pg_version(pgbin: &str) -> PostgresMajorVersion {
 }

 pub fn get_pg_version_string(pgbin: &str) -> String {
-    match get_pg_version(pgbin) {
-        PostgresMajorVersion::V14 => "v14",
-        PostgresMajorVersion::V15 => "v15",
-        PostgresMajorVersion::V16 => "v16",
-        PostgresMajorVersion::V17 => "v17",
-    }
-    .to_owned()
+    get_pg_version(pgbin).v_str()
 }

-#[derive(Copy, Clone, Debug, PartialEq, Eq)]
-pub enum PostgresMajorVersion {
-    V14,
-    V15,
-    V16,
-    V17,
-}
-
-fn parse_pg_version(human_version: &str) -> PostgresMajorVersion {
-    use PostgresMajorVersion::*;
+fn parse_pg_version(human_version: &str) -> PgMajorVersion {
+    use PgMajorVersion::*;
    // Normal releases have version strings like "PostgreSQL 15.4". But there
    // are also pre-release versions like "PostgreSQL 17devel" or "PostgreSQL
    // 16beta2" or "PostgreSQL 17rc1". And with the --with-extra-version
@@ -143,10 +129,10 @@ fn parse_pg_version(human_version: &str) -> PostgresMajorVersion {
        .captures(human_version)
    {
        Some(captures) if captures.len() == 2 => match &captures["major"] {
-            "14" => return V14,
-            "15" => return V15,
-            "16" => return V16,
-            "17" => return V17,
+            "14" => return PG14,
+            "15" => return PG15,
+            "16" => return PG16,
+            "17" => return PG17,
            _ => {}
        },
        _ => {}
@@ -310,10 +296,7 @@ async fn download_extension_tar(remote_ext_base_url: &Url, ext_path: &str) -> Re
 async fn do_extension_server_request(uri: Url) -> Result<Bytes, (String, String)> {
    let resp = reqwest::get(uri).await.map_err(|e| {
        (
-            format!(
-                "could not perform remote extensions server request: {:?}",
-                e
-            ),
+            format!("could not perform remote extensions server request: {e:?}"),
            UNKNOWN_HTTP_STATUS.to_string(),
        )
    })?;
@@ -323,7 +306,7 @@ async fn do_extension_server_request(uri: Url) -> Result<Bytes, (String, String)
        StatusCode::OK => match resp.bytes().await {
            Ok(resp) => Ok(resp),
            Err(e) => Err((
-                format!("could not read remote extensions server response: {:?}", e),
+                format!("could not read remote extensions server response: {e:?}"),
                // It's fine to return and report error with status as 200 OK,
                // because we still failed to read the response.
                status.to_string(),
@@ -334,10 +317,7 @@ async fn do_extension_server_request(uri: Url) -> Result<Bytes, (String, String)
            status.to_string(),
        )),
        _ => Err((
-            format!(
-                "unexpected remote extensions server response status code: {}",
-                status
-            ),
+            format!("unexpected remote extensions server response status code: {status}"),
            status.to_string(),
        )),
    }
@@ -349,25 +329,25 @@ mod tests {

    #[test]
    fn test_parse_pg_version() {
-        use super::PostgresMajorVersion::*;
-        assert_eq!(parse_pg_version("PostgreSQL 15.4"), V15);
-        assert_eq!(parse_pg_version("PostgreSQL 15.14"), V15);
+        use postgres_versioninfo::PgMajorVersion::*;
+        assert_eq!(parse_pg_version("PostgreSQL 15.4"), PG15);
+        assert_eq!(parse_pg_version("PostgreSQL 15.14"), PG15);
        assert_eq!(
            parse_pg_version("PostgreSQL 15.4 (Ubuntu 15.4-0ubuntu0.23.04.1)"),
-            V15
+            PG15
        );

-        assert_eq!(parse_pg_version("PostgreSQL 14.15"), V14);
-        assert_eq!(parse_pg_version("PostgreSQL 14.0"), V14);
+        assert_eq!(parse_pg_version("PostgreSQL 14.15"), PG14);
+        assert_eq!(parse_pg_version("PostgreSQL 14.0"), PG14);
        assert_eq!(
            parse_pg_version("PostgreSQL 14.9 (Debian 14.9-1.pgdg120+1"),
-            V14
+            PG14
        );

-        assert_eq!(parse_pg_version("PostgreSQL 16devel"), V16);
-        assert_eq!(parse_pg_version("PostgreSQL 16beta1"), V16);
-        assert_eq!(parse_pg_version("PostgreSQL 16rc2"), V16);
-        assert_eq!(parse_pg_version("PostgreSQL 16extra"), V16);
+        assert_eq!(parse_pg_version("PostgreSQL 16devel"), PG16);
+        assert_eq!(parse_pg_version("PostgreSQL 16beta1"), PG16);
+        assert_eq!(parse_pg_version("PostgreSQL 16rc2"), PG16);
+        assert_eq!(parse_pg_version("PostgreSQL 16extra"), PG16);
    }

    #[test]
--- a/compute_tools/src/http/routes/configure.rs
+++ b/compute_tools/src/http/routes/configure.rs
@@ -65,7 +65,7 @@ pub(in crate::http) async fn configure(

            if state.status == ComputeStatus::Failed {
                let err = state.error.as_ref().map_or("unknown error", |x| x);
-                let msg = format!("compute configuration failed: {:?}", err);
+                let msg = format!("compute configuration failed: {err:?}");
                return Err(msg);
            }
        }
--- a/compute_tools/src/installed_extensions.rs
+++ b/compute_tools/src/installed_extensions.rs
@@ -43,7 +43,7 @@ pub async fn get_installed_extensions(mut conf: Config) -> Result<InstalledExten
        let (mut client, connection) = conf.connect(NoTls).await?;
        tokio::spawn(async move {
            if let Err(e) = connection.await {
-                eprintln!("connection error: {}", e);
+                eprintln!("connection error: {e}");
            }
        });

@@ -57,7 +57,7 @@ pub async fn get_installed_extensions(mut conf: Config) -> Result<InstalledExten
        let (client, connection) = conf.connect(NoTls).await?;
        tokio::spawn(async move {
            if let Err(e) = connection.await {
-                eprintln!("connection error: {}", e);
+                eprintln!("connection error: {e}");
            }
        });

--- a/compute_tools/src/lsn_lease.rs
+++ b/compute_tools/src/lsn_lease.rs
@@ -4,7 +4,9 @@ use std::thread;
 use std::time::{Duration, SystemTime};

 use anyhow::{Result, bail};
-use compute_api::spec::ComputeMode;
+use compute_api::spec::{ComputeMode, PageserverProtocol};
+use itertools::Itertools as _;
+use pageserver_page_api as page_api;
 use postgres::{NoTls, SimpleQueryMessage};
 use tracing::{info, warn};
 use utils::id::{TenantId, TimelineId};
@@ -76,25 +78,17 @@ fn acquire_lsn_lease_with_retry(

    loop {
        // Note: List of pageservers is dynamic, need to re-read configs before each attempt.
-        let configs = {
+        let (connstrings, auth) = {
            let state = compute.state.lock().unwrap();
-
            let spec = state.pspec.as_ref().expect("spec must be set");
-
-            let conn_strings = spec.pageserver_connstr.split(',');
-
-            conn_strings
-                .map(|connstr| {
-                    let mut config = postgres::Config::from_str(connstr).expect("Invalid connstr");
-                    if let Some(storage_auth_token) = &spec.storage_auth_token {
-                        config.password(storage_auth_token.clone());
-                    }
-                    config
-                })
-                .collect::<Vec<_>>()
+            (
+                spec.pageserver_connstr.clone(),
+                spec.storage_auth_token.clone(),
+            )
        };

-        let result = try_acquire_lsn_lease(tenant_id, timeline_id, lsn, &configs);
+        let result =
+            try_acquire_lsn_lease(&connstrings, auth.as_deref(), tenant_id, timeline_id, lsn);
        match result {
            Ok(Some(res)) => {
                return Ok(res);
@@ -116,68 +110,104 @@ fn acquire_lsn_lease_with_retry(
    }
 }

-/// Tries to acquire an LSN lease through PS page_service API.
+/// Tries to acquire LSN leases on all Pageserver shards.
 fn try_acquire_lsn_lease(
+    connstrings: &str,
+    auth: Option<&str>,
    tenant_id: TenantId,
    timeline_id: TimelineId,
    lsn: Lsn,
-    configs: &[postgres::Config],
 ) -> Result<Option<SystemTime>> {
-    fn get_valid_until(
-        config: &postgres::Config,
-        tenant_shard_id: TenantShardId,
-        timeline_id: TimelineId,
-        lsn: Lsn,
-    ) -> Result<Option<SystemTime>> {
-        let mut client = config.connect(NoTls)?;
-        let cmd = format!("lease lsn {} {} {} ", tenant_shard_id, timeline_id, lsn);
-        let res = client.simple_query(&cmd)?;
-        let msg = match res.first() {
-            Some(msg) => msg,
-            None => bail!("empty response"),
-        };
-        let row = match msg {
-            SimpleQueryMessage::Row(row) => row,
-            _ => bail!("error parsing lsn lease response"),
+    let connstrings = connstrings.split(',').collect_vec();
+    let shard_count = connstrings.len();
+    let mut leases = Vec::new();
+
+    for (shard_number, &connstring) in connstrings.iter().enumerate() {
+        let tenant_shard_id = match shard_count {
+            0 | 1 => TenantShardId::unsharded(tenant_id),
+            shard_count => TenantShardId {
+                tenant_id,
+                shard_number: ShardNumber(shard_number as u8),
+                shard_count: ShardCount::new(shard_count as u8),
+            },
        };

-        // Note: this will be None if a lease is explicitly not granted.
-        let valid_until_str = row.get("valid_until");
-
-        let valid_until = valid_until_str.map(|s| {
-            SystemTime::UNIX_EPOCH
-                .checked_add(Duration::from_millis(u128::from_str(s).unwrap() as u64))
-                .expect("Time larger than max SystemTime could handle")
-        });
-        Ok(valid_until)
+        let lease = match PageserverProtocol::from_connstring(connstring)? {
+            PageserverProtocol::Libpq => {
+                acquire_lsn_lease_libpq(connstring, auth, tenant_shard_id, timeline_id, lsn)?
+            }
+            PageserverProtocol::Grpc => {
+                acquire_lsn_lease_grpc(connstring, auth, tenant_shard_id, timeline_id, lsn)?
+            }
+        };
+        leases.push(lease);
    }

-    let shard_count = configs.len();
+    Ok(leases.into_iter().min().flatten())
+}

-    let valid_until = if shard_count > 1 {
-        configs
-            .iter()
-            .enumerate()
-            .map(|(shard_number, config)| {
-                let tenant_shard_id = TenantShardId {
-                    tenant_id,
-                    shard_count: ShardCount::new(shard_count as u8),
-                    shard_number: ShardNumber(shard_number as u8),
-                };
-                get_valid_until(config, tenant_shard_id, timeline_id, lsn)
-            })
-            .collect::<Result<Vec<Option<SystemTime>>>>()?
-            .into_iter()
-            .min()
-            .unwrap()
-    } else {
-        get_valid_until(
-            &configs[0],
-            TenantShardId::unsharded(tenant_id),
-            timeline_id,
-            lsn,
-        )?
+/// Acquires an LSN lease on a single shard, using the libpq API. The connstring must use a
+/// postgresql:// scheme.
+fn acquire_lsn_lease_libpq(
+    connstring: &str,
+    auth: Option<&str>,
+    tenant_shard_id: TenantShardId,
+    timeline_id: TimelineId,
+    lsn: Lsn,
+) -> Result<Option<SystemTime>> {
+    let mut config = postgres::Config::from_str(connstring)?;
+    if let Some(auth) = auth {
+        config.password(auth);
+    }
+    let mut client = config.connect(NoTls)?;
+    let cmd = format!("lease lsn {tenant_shard_id} {timeline_id} {lsn} ");
+    let res = client.simple_query(&cmd)?;
+    let msg = match res.first() {
+        Some(msg) => msg,
+        None => bail!("empty response"),
+    };
+    let row = match msg {
+        SimpleQueryMessage::Row(row) => row,
+        _ => bail!("error parsing lsn lease response"),
    };

+    // Note: this will be None if a lease is explicitly not granted.
+    let valid_until_str = row.get("valid_until");
+
+    let valid_until = valid_until_str.map(|s| {
+        SystemTime::UNIX_EPOCH
+            .checked_add(Duration::from_millis(u128::from_str(s).unwrap() as u64))
+            .expect("Time larger than max SystemTime could handle")
+    });
    Ok(valid_until)
 }
+
+/// Acquires an LSN lease on a single shard, using the gRPC API. The connstring must use a
+/// grpc:// scheme.
+fn acquire_lsn_lease_grpc(
+    connstring: &str,
+    auth: Option<&str>,
+    tenant_shard_id: TenantShardId,
+    timeline_id: TimelineId,
+    lsn: Lsn,
+) -> Result<Option<SystemTime>> {
+    tokio::runtime::Handle::current().block_on(async move {
+        let mut client = page_api::Client::new(
+            connstring.to_string(),
+            tenant_shard_id.tenant_id,
+            timeline_id,
+            tenant_shard_id.to_index(),
+            auth.map(String::from),
+            None,
+        )
+        .await?;
+
+        let req = page_api::LeaseLsnRequest { lsn };
+        match client.lease_lsn(req).await {
+            Ok(expires) => Ok(Some(expires)),
+            // Lease couldn't be acquired because the LSN has been garbage collected.
+            Err(err) if err.code() == tonic::Code::FailedPrecondition => Ok(None),
+            Err(err) => Err(err.into()),
+        }
+    })
+}
--- a/compute_tools/src/pg_helpers.rs
+++ b/compute_tools/src/pg_helpers.rs
@@ -36,9 +36,9 @@ pub fn escape_literal(s: &str) -> String {
    let res = s.replace('\'', "''").replace('\\', "\\\\");

    if res.contains('\\') {
-        format!("E'{}'", res)
+        format!("E'{res}'")
    } else {
-        format!("'{}'", res)
+        format!("'{res}'")
    }
 }

@@ -46,7 +46,7 @@ pub fn escape_literal(s: &str) -> String {
 /// with `'{}'` is not required, as it returns a ready-to-use config string.
 pub fn escape_conf_value(s: &str) -> String {
    let res = s.replace('\'', "''").replace('\\', "\\\\");
-    format!("'{}'", res)
+    format!("'{res}'")
 }

 pub trait GenericOptionExt {
@@ -446,7 +446,7 @@ pub async fn tune_pgbouncer(
        let mut pgbouncer_connstr =
            "host=localhost port=6432 dbname=pgbouncer user=postgres sslmode=disable".to_string();
        if let Ok(pass) = std::env::var("PGBOUNCER_PASSWORD") {
-            pgbouncer_connstr.push_str(format!(" password={}", pass).as_str());
+            pgbouncer_connstr.push_str(format!(" password={pass}").as_str());
        }
        pgbouncer_connstr
    };
@@ -464,7 +464,7 @@ pub async fn tune_pgbouncer(
            Ok((client, connection)) => {
                tokio::spawn(async move {
                    if let Err(e) = connection.await {
-                        eprintln!("connection error: {}", e);
+                        eprintln!("connection error: {e}");
                    }
                });
                break client;
--- a/compute_tools/src/spec.rs
+++ b/compute_tools/src/spec.rs
@@ -23,12 +23,12 @@ fn do_control_plane_request(
 ) -> Result<ControlPlaneConfigResponse, (bool, String, String)> {
    let resp = reqwest::blocking::Client::new()
        .get(uri)
-        .header("Authorization", format!("Bearer {}", jwt))
+        .header("Authorization", format!("Bearer {jwt}"))
        .send()
        .map_err(|e| {
            (
                true,
-                format!("could not perform request to control plane: {:?}", e),
+                format!("could not perform request to control plane: {e:?}"),
                UNKNOWN_HTTP_STATUS.to_string(),
            )
        })?;
@@ -39,7 +39,7 @@ fn do_control_plane_request(
            Ok(spec_resp) => Ok(spec_resp),
            Err(e) => Err((
                true,
-                format!("could not deserialize control plane response: {:?}", e),
+                format!("could not deserialize control plane response: {e:?}"),
                status.to_string(),
            )),
        },
@@ -62,7 +62,7 @@ fn do_control_plane_request(
        // or some internal failure happened. Doesn't make much sense to retry in this case.
        _ => Err((
            false,
-            format!("unexpected control plane response status code: {}", status),
+            format!("unexpected control plane response status code: {status}"),
            status.to_string(),
        )),
    }
--- a/compute_tools/src/spec_apply.rs
+++ b/compute_tools/src/spec_apply.rs
@@ -933,56 +933,53 @@ async fn get_operations<'a>(
                PerDatabasePhase::DeleteDBRoleReferences => {
                    let ctx = ctx.read().await;

-                    let operations =
-                        spec.delta_operations
-                            .iter()
-                            .flatten()
-                            .filter(|op| op.action == "delete_role")
-                            .filter_map(move |op| {
-                                if db.is_owned_by(&op.name) {
-                                    return None;
-                                }
-                                if !ctx.roles.contains_key(&op.name) {
-                                    return None;
-                                }
-                                let quoted = op.name.pg_quote();
-                                let new_owner = match &db {
-                                    DB::SystemDB => PgIdent::from("cloud_admin").pg_quote(),
-                                    DB::UserDB(db) => db.owner.pg_quote(),
-                                };
-                                let (escaped_role, outer_tag) = op.name.pg_quote_dollar();
+                    let operations = spec
+                        .delta_operations
+                        .iter()
+                        .flatten()
+                        .filter(|op| op.action == "delete_role")
+                        .filter_map(move |op| {
+                            if db.is_owned_by(&op.name) {
+                                return None;
+                            }
+                            if !ctx.roles.contains_key(&op.name) {
+                                return None;
+                            }
+                            let quoted = op.name.pg_quote();
+                            let new_owner = match &db {
+                                DB::SystemDB => PgIdent::from("cloud_admin").pg_quote(),
+                                DB::UserDB(db) => db.owner.pg_quote(),
+                            };
+                            let (escaped_role, outer_tag) = op.name.pg_quote_dollar();

-                                Some(vec![
-                                    // This will reassign all dependent objects to the db owner
-                                    Operation {
-                                        query: format!(
-                                            "REASSIGN OWNED BY {} TO {}",
-                                            quoted, new_owner,
-                                        ),
-                                        comment: None,
-                                    },
-                                    // Revoke some potentially blocking privileges (Neon-specific currently)
-                                    Operation {
-                                        query: format!(
-                                            include_str!("sql/pre_drop_role_revoke_privileges.sql"),
-                                            // N.B. this has to be properly dollar-escaped with `pg_quote_dollar()`
-                                            role_name = escaped_role,
-                                            outer_tag = outer_tag,
-                                        ),
-                                        comment: None,
-                                    },
-                                    // This now will only drop privileges of the role
-                                    // TODO: this is obviously not 100% true because of the above case,
-                                    // there could be still some privileges that are not revoked. Maybe this
-                                    // only drops privileges that were granted *by this* role, not *to this* role,
-                                    // but this has to be checked.
-                                    Operation {
-                                        query: format!("DROP OWNED BY {}", quoted),
-                                        comment: None,
-                                    },
-                                ])
-                            })
-                            .flatten();
+                            Some(vec![
+                                // This will reassign all dependent objects to the db owner
+                                Operation {
+                                    query: format!("REASSIGN OWNED BY {quoted} TO {new_owner}",),
+                                    comment: None,
+                                },
+                                // Revoke some potentially blocking privileges (Neon-specific currently)
+                                Operation {
+                                    query: format!(
+                                        include_str!("sql/pre_drop_role_revoke_privileges.sql"),
+                                        // N.B. this has to be properly dollar-escaped with `pg_quote_dollar()`
+                                        role_name = escaped_role,
+                                        outer_tag = outer_tag,
+                                    ),
+                                    comment: None,
+                                },
+                                // This now will only drop privileges of the role
+                                // TODO: this is obviously not 100% true because of the above case,
+                                // there could be still some privileges that are not revoked. Maybe this
+                                // only drops privileges that were granted *by this* role, not *to this* role,
+                                // but this has to be checked.
+                                Operation {
+                                    query: format!("DROP OWNED BY {quoted}"),
+                                    comment: None,
+                                },
+                            ])
+                        })
+                        .flatten();

                    Ok(Box::new(operations))
                }
--- a/compute_tools/src/sync_sk.rs
+++ b/compute_tools/src/sync_sk.rs
@@ -27,7 +27,7 @@ pub async fn ping_safekeeper(
    let (client, conn) = config.connect(tokio_postgres::NoTls).await?;
    tokio::spawn(async move {
        if let Err(e) = conn.await {
-            eprintln!("connection error: {}", e);
+            eprintln!("connection error: {e}");
        }
    });

--- a/compute_tools/tests/cluster_spec.json
+++ b/compute_tools/tests/cluster_spec.json
@@ -3,7 +3,8 @@

  "timestamp": "2021-05-23T18:25:43.511Z",
  "operation_uuid": "0f657b36-4b0f-4a2d-9c2e-1dcd615e7d8b",
-
+  "suspend_timeout_seconds": 3600,
+  
  "cluster": {
    "cluster_id": "test-cluster-42",
    "name": "Zenith Test",
--- a/control_plane/src/bin/neon_local.rs
+++ b/control_plane/src/bin/neon_local.rs
@@ -16,9 +16,9 @@ use std::time::Duration;
 use anyhow::{Context, Result, anyhow, bail};
 use clap::Parser;
 use compute_api::requests::ComputeClaimsScope;
-use compute_api::spec::ComputeMode;
+use compute_api::spec::{ComputeMode, PageserverProtocol};
 use control_plane::broker::StorageBroker;
-use control_plane::endpoint::{ComputeControlPlane, EndpointTerminateMode, PageserverProtocol};
+use control_plane::endpoint::{ComputeControlPlane, EndpointTerminateMode};
 use control_plane::endpoint_storage::{ENDPOINT_STORAGE_DEFAULT_ADDR, EndpointStorage};
 use control_plane::local_env;
 use control_plane::local_env::{
@@ -48,7 +48,7 @@ use postgres_connection::parse_host_port;
 use safekeeper_api::membership::{SafekeeperGeneration, SafekeeperId};
 use safekeeper_api::{
    DEFAULT_HTTP_LISTEN_PORT as DEFAULT_SAFEKEEPER_HTTP_PORT,
-    DEFAULT_PG_LISTEN_PORT as DEFAULT_SAFEKEEPER_PG_PORT,
+    DEFAULT_PG_LISTEN_PORT as DEFAULT_SAFEKEEPER_PG_PORT, PgMajorVersion, PgVersionId,
 };
 use storage_broker::DEFAULT_LISTEN_ADDR as DEFAULT_BROKER_ADDR;
 use tokio::task::JoinSet;
@@ -64,7 +64,7 @@ const DEFAULT_PAGESERVER_ID: NodeId = NodeId(1);
 const DEFAULT_BRANCH_NAME: &str = "main";
 project_git_version!(GIT_VERSION);

-const DEFAULT_PG_VERSION: u32 = 17;
+const DEFAULT_PG_VERSION: PgMajorVersion = PgMajorVersion::PG17;

 const DEFAULT_PAGESERVER_CONTROL_PLANE_API: &str = "http://127.0.0.1:1234/upcall/v1/";

@@ -169,7 +169,7 @@ struct TenantCreateCmdArgs {

    #[arg(default_value_t = DEFAULT_PG_VERSION)]
    #[clap(long, help = "Postgres version to use for the initial timeline")]
-    pg_version: u32,
+    pg_version: PgMajorVersion,

    #[clap(
        long,
@@ -292,7 +292,7 @@ struct TimelineCreateCmdArgs {

    #[arg(default_value_t = DEFAULT_PG_VERSION)]
    #[clap(long, help = "Postgres version")]
-    pg_version: u32,
+    pg_version: PgMajorVersion,
 }

 #[derive(clap::Args)]
@@ -324,7 +324,7 @@ struct TimelineImportCmdArgs {

    #[arg(default_value_t = DEFAULT_PG_VERSION)]
    #[clap(long, help = "Postgres version of the backup being imported")]
-    pg_version: u32,
+    pg_version: PgMajorVersion,
 }

 #[derive(clap::Subcommand)]
@@ -603,7 +603,7 @@ struct EndpointCreateCmdArgs {

    #[arg(default_value_t = DEFAULT_PG_VERSION)]
    #[clap(long, help = "Postgres version")]
-    pg_version: u32,
+    pg_version: PgMajorVersion,

    /// Use gRPC to communicate with Pageservers, by generating grpc:// connstrings.
    ///
@@ -919,7 +919,7 @@ fn print_timeline(
            br_sym = "┗━";
        }

-        print!("{} @{}: ", br_sym, ancestor_lsn);
+        print!("{br_sym} @{ancestor_lsn}: ");
    }

    // Finally print a timeline id and name with new line
@@ -1295,7 +1295,7 @@ async fn handle_timeline(cmd: &TimelineCmd, env: &mut local_env::LocalEnv) -> Re
                    },
                    new_members: None,
                };
-                let pg_version = args.pg_version * 10000;
+                let pg_version = PgVersionId::from(args.pg_version);
                let req = safekeeper_api::models::TimelineCreateRequest {
                    tenant_id,
                    timeline_id,
@@ -1649,7 +1649,9 @@ async fn handle_endpoint(subcmd: &EndpointCmd, env: &local_env::LocalEnv) -> Res
            // If --safekeepers argument is given, use only the listed
            // safekeeper nodes; otherwise all from the env.
            let safekeepers = parse_safekeepers(&args.safekeepers)?;
-            endpoint.reconfigure(pageservers, None, safekeepers).await?;
+            endpoint
+                .reconfigure(Some(pageservers), None, safekeepers, None)
+                .await?;
        }
        EndpointCmd::Stop(args) => {
            let endpoint_id = &args.endpoint_id;
@@ -1742,7 +1744,7 @@ async fn handle_pageserver(subcmd: &PageserverCmd, env: &local_env::LocalEnv) ->
                StopMode::Immediate => true,
            };
            if let Err(e) = get_pageserver(env, args.pageserver_id)?.stop(immediate) {
-                eprintln!("pageserver stop failed: {}", e);
+                eprintln!("pageserver stop failed: {e}");
                exit(1);
            }
        }
@@ -1751,7 +1753,7 @@ async fn handle_pageserver(subcmd: &PageserverCmd, env: &local_env::LocalEnv) ->
            let pageserver = get_pageserver(env, args.pageserver_id)?;
            //TODO what shutdown strategy should we use here?
            if let Err(e) = pageserver.stop(false) {
-                eprintln!("pageserver stop failed: {}", e);
+                eprintln!("pageserver stop failed: {e}");
                exit(1);
            }

@@ -1768,7 +1770,7 @@ async fn handle_pageserver(subcmd: &PageserverCmd, env: &local_env::LocalEnv) ->
            {
                Ok(_) => println!("Page server is up and running"),
                Err(err) => {
-                    eprintln!("Page server is not available: {}", err);
+                    eprintln!("Page server is not available: {err}");
                    exit(1);
                }
            }
@@ -1805,7 +1807,7 @@ async fn handle_storage_controller(
                },
            };
            if let Err(e) = svc.stop(stop_args).await {
-                eprintln!("stop failed: {}", e);
+                eprintln!("stop failed: {e}");
                exit(1);
            }
        }
@@ -1827,7 +1829,7 @@ async fn handle_safekeeper(subcmd: &SafekeeperCmd, env: &local_env::LocalEnv) ->
            let safekeeper = get_safekeeper(env, args.id)?;

            if let Err(e) = safekeeper.start(&args.extra_opt, &args.start_timeout).await {
-                eprintln!("safekeeper start failed: {}", e);
+                eprintln!("safekeeper start failed: {e}");
                exit(1);
            }
        }
@@ -1839,7 +1841,7 @@ async fn handle_safekeeper(subcmd: &SafekeeperCmd, env: &local_env::LocalEnv) ->
                StopMode::Immediate => true,
            };
            if let Err(e) = safekeeper.stop(immediate) {
-                eprintln!("safekeeper stop failed: {}", e);
+                eprintln!("safekeeper stop failed: {e}");
                exit(1);
            }
        }
@@ -1852,12 +1854,12 @@ async fn handle_safekeeper(subcmd: &SafekeeperCmd, env: &local_env::LocalEnv) ->
            };

            if let Err(e) = safekeeper.stop(immediate) {
-                eprintln!("safekeeper stop failed: {}", e);
+                eprintln!("safekeeper stop failed: {e}");
                exit(1);
            }

            if let Err(e) = safekeeper.start(&args.extra_opt, &args.start_timeout).await {
-                eprintln!("safekeeper start failed: {}", e);
+                eprintln!("safekeeper start failed: {e}");
                exit(1);
            }
        }
@@ -2113,7 +2115,7 @@ async fn try_stop_all(env: &local_env::LocalEnv, immediate: bool) {

    let storage = EndpointStorage::from_env(env);
    if let Err(e) = storage.stop(immediate) {
-        eprintln!("endpoint_storage stop failed: {:#}", e);
+        eprintln!("endpoint_storage stop failed: {e:#}");
    }

    for ps_conf in &env.pageservers {
--- a/control_plane/src/endpoint.rs
+++ b/control_plane/src/endpoint.rs
@@ -56,8 +56,8 @@ use compute_api::responses::{
    TlsConfig,
 };
 use compute_api::spec::{
-    Cluster, ComputeAudit, ComputeFeature, ComputeMode, ComputeSpec, Database, PgIdent,
-    RemoteExtSpec, Role,
+    Cluster, ComputeAudit, ComputeFeature, ComputeMode, ComputeSpec, Database, PageserverProtocol,
+    PgIdent, RemoteExtSpec, Role,
 };
 use jsonwebtoken::jwk::{
    AlgorithmParameters, CommonParameters, EllipticCurve, Jwk, JwkSet, KeyAlgorithm, KeyOperations,
@@ -67,6 +67,7 @@ use nix::sys::signal::{Signal, kill};
 use pageserver_api::shard::ShardStripeSize;
 use pem::Pem;
 use reqwest::header::CONTENT_TYPE;
+use safekeeper_api::PgMajorVersion;
 use safekeeper_api::membership::SafekeeperGeneration;
 use serde::{Deserialize, Serialize};
 use sha2::{Digest, Sha256};
@@ -89,7 +90,7 @@ pub struct EndpointConf {
    pg_port: u16,
    external_http_port: u16,
    internal_http_port: u16,
-    pg_version: u32,
+    pg_version: PgMajorVersion,
    grpc: bool,
    skip_pg_catalog_updates: bool,
    reconfigure_concurrency: usize,
@@ -192,7 +193,7 @@ impl ComputeControlPlane {
        pg_port: Option<u16>,
        external_http_port: Option<u16>,
        internal_http_port: Option<u16>,
-        pg_version: u32,
+        pg_version: PgMajorVersion,
        mode: ComputeMode,
        grpc: bool,
        skip_pg_catalog_updates: bool,
@@ -312,7 +313,7 @@ pub struct Endpoint {
    pub internal_http_address: SocketAddr,

    // postgres major version in the format: 14, 15, etc.
-    pg_version: u32,
+    pg_version: PgMajorVersion,

    // These are not part of the endpoint as such, but the environment
    // the endpoint runs in.
@@ -372,29 +373,6 @@ impl std::fmt::Display for EndpointTerminateMode {
    }
 }

-/// Protocol used to connect to a Pageserver.
-#[derive(Clone, Copy, Debug)]
-pub enum PageserverProtocol {
-    Libpq,
-    Grpc,
-}
-
-impl PageserverProtocol {
-    /// Returns the URL scheme for the protocol, used in connstrings.
-    pub fn scheme(&self) -> &'static str {
-        match self {
-            Self::Libpq => "postgresql",
-            Self::Grpc => "grpc",
-        }
-    }
-}
-
-impl Display for PageserverProtocol {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        f.write_str(self.scheme())
-    }
-}
-
 impl Endpoint {
    fn from_dir_entry(entry: std::fs::DirEntry, env: &LocalEnv) -> Result<Endpoint> {
        if !entry.file_type()?.is_dir() {
@@ -557,7 +535,7 @@ impl Endpoint {
                conf.append("hot_standby", "on");
                // prefetching of blocks referenced in WAL doesn't make sense for us
                // Neon hot standby ignores pages that are not in the shared_buffers
-                if self.pg_version >= 15 {
+                if self.pg_version >= PgMajorVersion::PG15 {
                    conf.append("recovery_prefetch", "off");
                }
            }
@@ -802,6 +780,7 @@ impl Endpoint {
                endpoint_storage_addr: Some(endpoint_storage_addr),
                endpoint_storage_token: Some(endpoint_storage_token),
                autoprewarm: false,
+                suspend_timeout_seconds: -1, // Only used in neon_local.
            };

            // this strange code is needed to support respec() in tests
@@ -846,10 +825,10 @@ impl Endpoint {

        // Launch compute_ctl
        let conn_str = self.connstr("cloud_admin", "postgres");
-        println!("Starting postgres node at '{}'", conn_str);
+        println!("Starting postgres node at '{conn_str}'");
        if create_test_user {
            let conn_str = self.connstr("test", "neondb");
-            println!("Also at '{}'", conn_str);
+            println!("Also at '{conn_str}'");
        }
        let mut cmd = Command::new(self.env.neon_distrib_dir.join("compute_ctl"));
        cmd.args([
@@ -948,8 +927,7 @@ impl Endpoint {
                Err(e) => {
                    if Instant::now().duration_since(start_at) > start_timeout {
                        return Err(e).context(format!(
-                            "timed out {:?} waiting to connect to compute_ctl HTTP",
-                            start_timeout,
+                            "timed out {start_timeout:?} waiting to connect to compute_ctl HTTP",
                        ));
                    }
                }
@@ -988,7 +966,7 @@ impl Endpoint {
            // reqwest does not export its error construction utility functions, so let's craft the message ourselves
            let url = response.url().to_owned();
            let msg = match response.text().await {
-                Ok(err_body) => format!("Error: {}", err_body),
+                Ok(err_body) => format!("Error: {err_body}"),
                Err(_) => format!("Http error ({}) at {}.", status.as_u16(), url),
            };
            Err(anyhow::anyhow!(msg))
@@ -997,12 +975,11 @@ impl Endpoint {

    pub async fn reconfigure(
        &self,
-        pageservers: Vec<(PageserverProtocol, Host, u16)>,
+        pageservers: Option<Vec<(PageserverProtocol, Host, u16)>>,
        stripe_size: Option<ShardStripeSize>,
        safekeepers: Option<Vec<NodeId>>,
+        safekeeper_generation: Option<SafekeeperGeneration>,
    ) -> Result<()> {
-        anyhow::ensure!(!pageservers.is_empty(), "no pageservers provided");
-
        let (mut spec, compute_ctl_config) = {
            let config_path = self.endpoint_path().join("config.json");
            let file = std::fs::File::open(config_path)?;
@@ -1014,16 +991,24 @@ impl Endpoint {
        let postgresql_conf = self.read_postgresql_conf()?;
        spec.cluster.postgresql_conf = Some(postgresql_conf);

-        let pageserver_connstr = Self::build_pageserver_connstr(&pageservers);
-        spec.pageserver_connstring = Some(pageserver_connstr);
-        if stripe_size.is_some() {
-            spec.shard_stripe_size = stripe_size.map(|s| s.0 as usize);
+        // If pageservers are not specified, don't change them.
+        if let Some(pageservers) = pageservers {
+            anyhow::ensure!(!pageservers.is_empty(), "no pageservers provided");
+
+            let pageserver_connstr = Self::build_pageserver_connstr(&pageservers);
+            spec.pageserver_connstring = Some(pageserver_connstr);
+            if stripe_size.is_some() {
+                spec.shard_stripe_size = stripe_size.map(|s| s.0 as usize);
+            }
        }

        // If safekeepers are not specified, don't change them.
        if let Some(safekeepers) = safekeepers {
            let safekeeper_connstrings = self.build_safekeepers_connstrs(safekeepers)?;
            spec.safekeeper_connstrings = safekeeper_connstrings;
+            if let Some(g) = safekeeper_generation {
+                spec.safekeepers_generation = Some(g.into_inner());
+            }
        }

        let client = reqwest::Client::builder()
@@ -1054,13 +1039,31 @@ impl Endpoint {
        } else {
            let url = response.url().to_owned();
            let msg = match response.text().await {
-                Ok(err_body) => format!("Error: {}", err_body),
+                Ok(err_body) => format!("Error: {err_body}"),
                Err(_) => format!("Http error ({}) at {}.", status.as_u16(), url),
            };
            Err(anyhow::anyhow!(msg))
        }
    }

+    pub async fn reconfigure_pageservers(
+        &self,
+        pageservers: Vec<(PageserverProtocol, Host, u16)>,
+        stripe_size: Option<ShardStripeSize>,
+    ) -> Result<()> {
+        self.reconfigure(Some(pageservers), stripe_size, None, None)
+            .await
+    }
+
+    pub async fn reconfigure_safekeepers(
+        &self,
+        safekeepers: Vec<NodeId>,
+        generation: SafekeeperGeneration,
+    ) -> Result<()> {
+        self.reconfigure(None, None, Some(safekeepers), Some(generation))
+            .await
+    }
+
    pub async fn stop(
        &self,
        mode: EndpointTerminateMode,
--- a/control_plane/src/local_env.rs
+++ b/control_plane/src/local_env.rs
@@ -12,9 +12,11 @@ use std::{env, fs};

 use anyhow::{Context, bail};
 use clap::ValueEnum;
+use pageserver_api::config::PostHogConfig;
 use pem::Pem;
 use postgres_backend::AuthType;
 use reqwest::{Certificate, Url};
+use safekeeper_api::PgMajorVersion;
 use serde::{Deserialize, Serialize};
 use utils::auth::encode_from_key_file;
 use utils::id::{NodeId, TenantId, TenantTimelineId, TimelineId};
@@ -210,7 +212,11 @@ pub struct NeonStorageControllerConf {

    pub use_local_compute_notifications: bool,

-    pub timeline_safekeeper_count: Option<i64>,
+    pub timeline_safekeeper_count: Option<usize>,
+
+    pub posthog_config: Option<PostHogConfig>,
+
+    pub kick_secondary_downloads: Option<bool>,
 }

 impl NeonStorageControllerConf {
@@ -242,6 +248,8 @@ impl Default for NeonStorageControllerConf {
            use_https_safekeeper_api: false,
            use_local_compute_notifications: true,
            timeline_safekeeper_count: None,
+            posthog_config: None,
+            kick_secondary_downloads: None,
        }
    }
 }
@@ -257,7 +265,7 @@ impl Default for EndpointStorageConf {
 impl NeonBroker {
    pub fn client_url(&self) -> Url {
        let url = if let Some(addr) = self.listen_https_addr {
-            format!("https://{}", addr)
+            format!("https://{addr}")
        } else {
            format!(
                "http://{}",
@@ -421,25 +429,21 @@ impl LocalEnv {
        self.pg_distrib_dir.clone()
    }

-    pub fn pg_distrib_dir(&self, pg_version: u32) -> anyhow::Result<PathBuf> {
+    pub fn pg_distrib_dir(&self, pg_version: PgMajorVersion) -> anyhow::Result<PathBuf> {
        let path = self.pg_distrib_dir.clone();

-        #[allow(clippy::manual_range_patterns)]
-        match pg_version {
-            14 | 15 | 16 | 17 => Ok(path.join(format!("v{pg_version}"))),
-            _ => bail!("Unsupported postgres version: {}", pg_version),
-        }
+        Ok(path.join(pg_version.v_str()))
    }

-    pub fn pg_dir(&self, pg_version: u32, dir_name: &str) -> anyhow::Result<PathBuf> {
+    pub fn pg_dir(&self, pg_version: PgMajorVersion, dir_name: &str) -> anyhow::Result<PathBuf> {
        Ok(self.pg_distrib_dir(pg_version)?.join(dir_name))
    }

-    pub fn pg_bin_dir(&self, pg_version: u32) -> anyhow::Result<PathBuf> {
+    pub fn pg_bin_dir(&self, pg_version: PgMajorVersion) -> anyhow::Result<PathBuf> {
        self.pg_dir(pg_version, "bin")
    }

-    pub fn pg_lib_dir(&self, pg_version: u32) -> anyhow::Result<PathBuf> {
+    pub fn pg_lib_dir(&self, pg_version: PgMajorVersion) -> anyhow::Result<PathBuf> {
        self.pg_dir(pg_version, "lib")
    }

@@ -730,7 +734,7 @@ impl LocalEnv {
                let config_toml_path = dentry.path().join("pageserver.toml");
                let config_toml: PageserverConfigTomlSubset = toml_edit::de::from_str(
                    &std::fs::read_to_string(&config_toml_path)
-                        .with_context(|| format!("read {:?}", config_toml_path))?,
+                        .with_context(|| format!("read {config_toml_path:?}"))?,
                )
                .context("parse pageserver.toml")?;
                let identity_toml_path = dentry.path().join("identity.toml");
@@ -740,7 +744,7 @@ impl LocalEnv {
                }
                let identity_toml: IdentityTomlSubset = toml_edit::de::from_str(
                    &std::fs::read_to_string(&identity_toml_path)
-                        .with_context(|| format!("read {:?}", identity_toml_path))?,
+                        .with_context(|| format!("read {identity_toml_path:?}"))?,
                )
                .context("parse identity.toml")?;
                let PageserverConfigTomlSubset {
--- a/control_plane/src/pageserver.rs
+++ b/control_plane/src/pageserver.rs
@@ -22,6 +22,7 @@ use pageserver_api::shard::TenantShardId;
 use pageserver_client::mgmt_api;
 use postgres_backend::AuthType;
 use postgres_connection::{PgConnectionConfig, parse_host_port};
+use safekeeper_api::PgMajorVersion;
 use utils::auth::{Claims, Scope};
 use utils::id::{NodeId, TenantId, TimelineId};
 use utils::lsn::Lsn;
@@ -121,7 +122,7 @@ impl PageServerNode {
                .env
                .generate_auth_token(&Claims::new(None, Scope::GenerationsApi))
                .unwrap();
-            overrides.push(format!("control_plane_api_token='{}'", jwt_token));
+            overrides.push(format!("control_plane_api_token='{jwt_token}'"));
        }

        if !conf.other.contains_key("remote_storage") {
@@ -607,7 +608,7 @@ impl PageServerNode {
        timeline_id: TimelineId,
        base: (Lsn, PathBuf),
        pg_wal: Option<(Lsn, PathBuf)>,
-        pg_version: u32,
+        pg_version: PgMajorVersion,
    ) -> anyhow::Result<()> {
        // Init base reader
        let (start_lsn, base_tarfile_path) = base;
--- a/control_plane/src/safekeeper.rs
+++ b/control_plane/src/safekeeper.rs
@@ -143,7 +143,7 @@ impl SafekeeperNode {
        let id_string = id.to_string();
        // TODO: add availability_zone to the config.
        // Right now we just specify any value here and use it to check metrics in tests.
-        let availability_zone = format!("sk-{}", id_string);
+        let availability_zone = format!("sk-{id_string}");

        let mut args = vec![
            "-D".to_owned(),
--- a/control_plane/src/storage_controller.rs
+++ b/control_plane/src/storage_controller.rs
@@ -6,6 +6,8 @@ use std::str::FromStr;
 use std::sync::OnceLock;
 use std::time::{Duration, Instant};

+use crate::background_process;
+use crate::local_env::{LocalEnv, NeonStorageControllerConf};
 use camino::{Utf8Path, Utf8PathBuf};
 use hyper0::Uri;
 use nix::unistd::Pid;
@@ -22,6 +24,7 @@ use pageserver_client::mgmt_api::ResponseErrorMessageExt;
 use pem::Pem;
 use postgres_backend::AuthType;
 use reqwest::{Method, Response};
+use safekeeper_api::PgMajorVersion;
 use serde::de::DeserializeOwned;
 use serde::{Deserialize, Serialize};
 use tokio::process::Command;
@@ -31,9 +34,6 @@ use utils::auth::{Claims, Scope, encode_from_key_file};
 use utils::id::{NodeId, TenantId};
 use whoami::username;

-use crate::background_process;
-use crate::local_env::{LocalEnv, NeonStorageControllerConf};
-
 pub struct StorageController {
    env: LocalEnv,
    private_key: Option<Pem>,
@@ -48,7 +48,7 @@ pub struct StorageController {

 const COMMAND: &str = "storage_controller";

-const STORAGE_CONTROLLER_POSTGRES_VERSION: u32 = 16;
+const STORAGE_CONTROLLER_POSTGRES_VERSION: PgMajorVersion = PgMajorVersion::PG16;

 const DB_NAME: &str = "storage_controller";

@@ -167,7 +167,7 @@ impl StorageController {
    fn storage_controller_instance_dir(&self, instance_id: u8) -> PathBuf {
        self.env
            .base_data_dir
-            .join(format!("storage_controller_{}", instance_id))
+            .join(format!("storage_controller_{instance_id}"))
    }

    fn pid_file(&self, instance_id: u8) -> Utf8PathBuf {
@@ -184,9 +184,15 @@ impl StorageController {
    /// to other versions if that one isn't found.  Some automated tests create circumstances
    /// where only one version is available in pg_distrib_dir, such as `test_remote_extensions`.
    async fn get_pg_dir(&self, dir_name: &str) -> anyhow::Result<Utf8PathBuf> {
-        let prefer_versions = [STORAGE_CONTROLLER_POSTGRES_VERSION, 16, 15, 14];
+        const PREFER_VERSIONS: [PgMajorVersion; 5] = [
+            STORAGE_CONTROLLER_POSTGRES_VERSION,
+            PgMajorVersion::PG16,
+            PgMajorVersion::PG15,
+            PgMajorVersion::PG14,
+            PgMajorVersion::PG17,
+        ];

-        for v in prefer_versions {
+        for v in PREFER_VERSIONS {
            let path = Utf8PathBuf::from_path_buf(self.env.pg_dir(v, dir_name)?).unwrap();
            if tokio::fs::try_exists(&path).await? {
                return Ok(path);
@@ -220,7 +226,7 @@ impl StorageController {
            "-d",
            DB_NAME,
            "-p",
-            &format!("{}", postgres_port),
+            &format!("{postgres_port}"),
        ];
        let pg_lib_dir = self.get_pg_lib_dir().await.unwrap();
        let envs = [
@@ -263,7 +269,7 @@ impl StorageController {
                "-h",
                "localhost",
                "-p",
-                &format!("{}", postgres_port),
+                &format!("{postgres_port}"),
                "-U",
                &username(),
                "-O",
@@ -425,7 +431,7 @@ impl StorageController {
            // from `LocalEnv`'s config file (`.neon/config`).
            tokio::fs::write(
                &pg_data_path.join("postgresql.conf"),
-                format!("port = {}\nfsync=off\n", postgres_port),
+                format!("port = {postgres_port}\nfsync=off\n"),
            )
            .await?;

@@ -477,7 +483,7 @@ impl StorageController {
            self.setup_database(postgres_port).await?;
        }

-        let database_url = format!("postgresql://localhost:{}/{DB_NAME}", postgres_port);
+        let database_url = format!("postgresql://localhost:{postgres_port}/{DB_NAME}");

        // We support running a startup SQL script to fiddle with the database before we launch storcon.
        // This is used by the test suite.
@@ -508,7 +514,7 @@ impl StorageController {
        drop(client);
        conn.await??;

-        let addr = format!("{}:{}", host, listen_port);
+        let addr = format!("{host}:{listen_port}");
        let address_for_peers = Uri::builder()
            .scheme(scheme)
            .authority(addr.clone())
@@ -557,6 +563,10 @@ impl StorageController {
            args.push("--use-local-compute-notifications".to_string());
        }

+        if let Some(value) = self.config.kick_secondary_downloads {
+            args.push(format!("--kick-secondary-downloads={value}"));
+        }
+
        if let Some(ssl_ca_file) = self.env.ssl_ca_cert_path() {
            args.push(format!("--ssl-ca-file={}", ssl_ca_file.to_str().unwrap()));
        }
@@ -628,10 +638,28 @@ impl StorageController {
            args.push("--timelines-onto-safekeepers".to_string());
        }

-        if let Some(sk_cnt) = self.config.timeline_safekeeper_count {
+        // neon_local is used in test environments where we often have less than 3 safekeepers.
+        if self.config.timeline_safekeeper_count.is_some() || self.env.safekeepers.len() < 3 {
+            let sk_cnt = self
+                .config
+                .timeline_safekeeper_count
+                .unwrap_or(self.env.safekeepers.len());
+
            args.push(format!("--timeline-safekeeper-count={sk_cnt}"));
        }

+        let mut envs = vec![
+            ("LD_LIBRARY_PATH".to_owned(), pg_lib_dir.to_string()),
+            ("DYLD_LIBRARY_PATH".to_owned(), pg_lib_dir.to_string()),
+        ];
+
+        if let Some(posthog_config) = &self.config.posthog_config {
+            envs.push((
+                "POSTHOG_CONFIG".to_string(),
+                serde_json::to_string(posthog_config)?,
+            ));
+        }
+
        println!("Starting storage controller");

        background_process::start_process(
@@ -639,10 +667,7 @@ impl StorageController {
            &instance_dir,
            &self.env.storage_controller_bin(),
            args,
-            vec![
-                ("LD_LIBRARY_PATH".to_owned(), pg_lib_dir.to_string()),
-                ("DYLD_LIBRARY_PATH".to_owned(), pg_lib_dir.to_string()),
-            ],
+            envs,
            background_process::InitialPidFile::Create(self.pid_file(start_args.instance_id)),
            &start_args.start_timeout,
            || async {
@@ -806,9 +831,9 @@ impl StorageController {
            builder = builder.json(&body)
        }
        if let Some(private_key) = &self.private_key {
-            println!("Getting claims for path {}", path);
+            println!("Getting claims for path {path}");
            if let Some(required_claims) = Self::get_claims_for_path(&path)? {
-                println!("Got claims {:?} for path {}", required_claims, path);
+                println!("Got claims {required_claims:?} for path {path}");
                let jwt_token = encode_from_key_file(&required_claims, private_key)?;
                builder = builder.header(
                    reqwest::header::AUTHORIZATION,
--- a/control_plane/storcon_cli/src/main.rs
+++ b/control_plane/storcon_cli/src/main.rs
@@ -649,7 +649,7 @@ async fn main() -> anyhow::Result<()> {
                response
                    .new_shards
                    .iter()
-                    .map(|s| format!("{:?}", s))
+                    .map(|s| format!("{s:?}"))
                    .collect::<Vec<_>>()
                    .join(",")
            );
@@ -771,8 +771,8 @@ async fn main() -> anyhow::Result<()> {

            println!("Tenant {tenant_id}");
            let mut table = comfy_table::Table::new();
-            table.add_row(["Policy", &format!("{:?}", policy)]);
-            table.add_row(["Stripe size", &format!("{:?}", stripe_size)]);
+            table.add_row(["Policy", &format!("{policy:?}")]);
+            table.add_row(["Stripe size", &format!("{stripe_size:?}")]);
            table.add_row(["Config", &serde_json::to_string_pretty(&config).unwrap()]);
            println!("{table}");
            println!("Shards:");
@@ -789,7 +789,7 @@ async fn main() -> anyhow::Result<()> {
                let secondary = shard
                    .node_secondary
                    .iter()
-                    .map(|n| format!("{}", n))
+                    .map(|n| format!("{n}"))
                    .collect::<Vec<_>>()
                    .join(",");

@@ -863,7 +863,7 @@ async fn main() -> anyhow::Result<()> {
                }
            } else {
                // Make it obvious to the user that since they've omitted an AZ, we're clearing it
-                eprintln!("Clearing preferred AZ for tenant {}", tenant_id);
+                eprintln!("Clearing preferred AZ for tenant {tenant_id}");
            }

            // Construct a request that modifies all the tenant's shards
@@ -1134,8 +1134,7 @@ async fn main() -> anyhow::Result<()> {
                    Err((tenant_shard_id, from, to, error)) => {
                        failure += 1;
                        println!(
-                            "Failed to migrate {} from node {} to node {}: {}",
-                            tenant_shard_id, from, to, error
+                            "Failed to migrate {tenant_shard_id} from node {from} to node {to}: {error}"
                        );
                    }
                }
@@ -1277,8 +1276,7 @@ async fn main() -> anyhow::Result<()> {
            concurrency,
        } => {
            let mut path = format!(
-                "/v1/tenant/{}/timeline/{}/download_heatmap_layers",
-                tenant_shard_id, timeline_id,
+                "/v1/tenant/{tenant_shard_id}/timeline/{timeline_id}/download_heatmap_layers",
            );

            if let Some(c) = concurrency {
@@ -1303,8 +1301,7 @@ async fn watch_tenant_shard(
 ) -> anyhow::Result<()> {
    if let Some(until_migrated_to) = until_migrated_to {
        println!(
-            "Waiting for tenant shard {} to be migrated to node {}",
-            tenant_shard_id, until_migrated_to
+            "Waiting for tenant shard {tenant_shard_id} to be migrated to node {until_migrated_to}"
        );
    }

@@ -1327,7 +1324,7 @@ async fn watch_tenant_shard(
            "attached: {} secondary: {} {}",
            shard
                .node_attached
-                .map(|n| format!("{}", n))
+                .map(|n| format!("{n}"))
                .unwrap_or("none".to_string()),
            shard
                .node_secondary
@@ -1341,15 +1338,12 @@ async fn watch_tenant_shard(
                "(reconciler idle)"
            }
        );
-        println!("{}", summary);
+        println!("{summary}");

        // Maybe drop out if we finished migration
        if let Some(until_migrated_to) = until_migrated_to {
            if shard.node_attached == Some(until_migrated_to) && !shard.is_reconciling {
-                println!(
-                    "Tenant shard {} is now on node {}",
-                    tenant_shard_id, until_migrated_to
-                );
+                println!("Tenant shard {tenant_shard_id} is now on node {until_migrated_to}");
                break;
            }
        }
--- a/docker-compose/compute_wrapper/var/db/postgres/configs/config.json
+++ b/docker-compose/compute_wrapper/var/db/postgres/configs/config.json
@@ -4,6 +4,7 @@

        "timestamp": "2022-10-12T18:00:00.000Z",
        "operation_uuid": "0f657b36-4b0f-4a2d-9c2e-1dcd615e7d8c",
+        "suspend_timeout_seconds": -1,

        "cluster": {
            "cluster_id": "docker_compose",
--- a/docs/rfcs/040-Endpoint-Persistent-Unlogged-Files-Storage.md
+++ b/docs/rfcs/040-Endpoint-Persistent-Unlogged-Files-Storage.md
@@ -0,0 +1,396 @@
+# Memo: Endpoint Persistent Unlogged Files Storage
+Created on 2024-11-05
+Implemented on N/A
+
+## Summary
+A design for a storage system that allows storage of files required to make
+Neon's Endpoints have a better experience at or after a reboot.
+
+## Motivation
+Several systems inside PostgreSQL (and Neon) need some persistent storage for
+optimal workings across reboots and restarts, but still work without.
+Examples are the query-level statistics files of `pg_stat_statements` in
+`pg_stat/pg_stat_statements.stat`, and `pg_prewarm`'s `autoprewarm.blocks`.
+We need a storage system that can store and manage these files for each
+Endpoint, without necessarily granting users access to an unlimited storage
+device.
+
+## Goals
+- Store known files for Endpoints with reasonable persistence.  
+  _Data loss in this service, while annoying and bad for UX, won't lose any
+  customer's data._
+
+## Non Goals (if relevant)
+- This storage system does not need branching, file versioning, or other such
+  features. The files are as ephemeral to the timeline of the data as the
+  Endpoints that host the data.
+- This storage system does not need to store _all_ user files, only 'known'
+  user files.
+- This storage system does not need to be hosted fully inside Computes.  
+  _Instead, this will be a separate component similar to Pageserver,
+  SafeKeeper, the S3 proxy used for dynamically loaded extensions, etc._
+
+## Impacted components
+- Compute needs new code to load and store these files in its lifetime.
+- Control Plane needs to consider this new storage system when signalling
+  the deletion of an Endpoint, Timeline, or Tenant.
+- Control Plane needs to consider this new storage system when it resets
+  or re-assigns an endpoint's timeline/branch state.
+
+A new service is created: the Endpoint Persistent Unlogged Files Storage
+service.  This could be integrated in e.g. Pageserver or Control Plane, or a
+separately hosted service.
+
+## Proposed implementation
+Endpoint-related data files are managed by a newly designed service (which
+optionally is integrated in an existing service like Pageserver or Control
+Plane), which stores data directly into S3 or any blob storage of choice.
+
+Upon deletion of the Endpoint, or reassignment of the endpoint to a different
+branch, this ephemeral data is dropped: the data stored may not match the
+state of the branch's data after reassignment, and on endpoint deletion the
+data won't have any use to the user.
+
+Compute gets credentials (JWT token with Tenant, Timeline & Endpoint claims)
+which it can use to authenticate to this new service and retrieve and store
+data associated with this endpoint.  This limited scope reduces leaks of data
+across endpoints and timeline resets, and limits the ability of endpoints to
+mess with other endpoints' data.
+
+The path of this endpoint data in S3 is initially as follows:
+
+    s3://<regional-epufs-bucket>/
+      tenants/
+        <hex-tenant-id>/
+          tenants/
+            <hex-timeline-id>/
+              endpoints/
+                <endpoint-id>/
+                  pgdata/
+                    <file_path_in_pgdatadir>
+
+For other blob storages an equivalent or similar path can be constructed.
+
+### Reliability, failure modes and corner cases (if relevant)
+Reliability is important, but not critical to the workings of Neon.  The data
+stored in this service will, when lost, reduce performance, but won't be a
+cause of permanent data loss - only operational metadata is stored.
+
+Most, if not all, blob storage services have sufficiently high persistence
+guarantees to cater our need for persistence and uptime. The only concern with
+blob storages is that the access latency is generally higher than local disk,
+but for the object types stored (cache state, ...) I don't think this will be
+much of an issue.
+
+### Interaction/Sequence diagram (if relevant)
+
+In these diagrams you can replace S3 with any persistent storage device of
+choice, but S3 is chosen as representative name: The well-known and short name
+of AWS' blob storage. Azure Blob Storage should work too, but it has a much
+longer name making it less practical for the diagrams.
+
+Write data:
+
+```http
+POST /tenants/<tenant-id>/timelines/<tl-id>/endpoints/<endpoint-id>/pgdata/<the-pgdata-path>
+Host: epufs.svc.neon.local
+
+<<<
+
+200 OK
+{
+  "version": "<opaque>", # opaque file version token, changes when the file contents change
+  "size": <bytes>,
+}
+```
+
+```mermaid
+sequenceDiagram
+    autonumber
+    participant co as Compute
+    participant ep as EPUFS
+    participant s3 as Blob Storage
+
+    co-->ep: Connect with credentials
+    co->>+ep: Store Unlogged Persistent File
+    opt is authenticated
+        ep->>s3: Write UPF to S3
+    end
+    ep->>-co: OK / Failure / Auth Failure
+    co-->ep: Cancel connection
+```
+
+Read data: (optional with cache-relevant request parameters, e.g. If-Modified-Since)
+```http
+GET /tenants/<tenant-id>/timelines/<tl-id>/endpoints/<endpoint-id>/pgdata/<the-pgdata-path>
+Host: epufs.svc.neon.local
+
+<<<
+
+200 OK
+
+<file data>
+```
+
+```mermaid
+sequenceDiagram
+    autonumber
+    participant co as Compute
+    participant ep as EPUFS
+    participant s3 as Blob Storage
+
+    co->>+ep: Read Unlogged Persistent File
+    opt is authenticated
+        ep->>+s3: Request UPF from storage
+        s3->>-ep: Receive UPF from storage
+    end
+    ep->>-co: OK(response) / Failure(storage, auth, ...)
+```
+
+Compute Startup:
+```mermaid
+sequenceDiagram
+    autonumber
+    participant co as Compute
+    participant ps as Pageserver
+    participant ep as EPUFS
+    participant es as Extension server
+
+    note over co: Bind endpoint ep-xxx
+    par Get basebackup
+        co->>+ps: Request basebackup @ LSN
+        ps-)ps: Construct basebackup
+        ps->>-co: Receive basebackup TAR @ LSN
+    and Get startup-critical Unlogged Persistent Files
+        co->>+ep: Get all UPFs of endpoint ep-xxx
+        ep-)ep: Retrieve and gather all UPFs
+        ep->>-co: TAR of UPFs
+    and Get startup-critical extensions
+        loop For every startup-critical extension
+            co->>es: Get critical extension
+            es->>co: Receive critical extension
+        end
+    end
+    note over co: Start compute
+```
+
+CPlane ops:
+```http
+DELETE /tenants/<tenant-id>/timelines/<timeline-id>/endpoints/<endpoint-id>
+Host: epufs.svc.neon.local
+
+<<<
+
+200 OK
+{
+  "tenant": "<tenant-id>",
+  "timeline": "<timeline-id>",
+  "endpoint": "<endpoint-id>",
+  "deleted": {
+    "files": <count>,
+    "bytes": <count>,
+  },
+}
+```
+
+```http
+DELETE /tenants/<tenant-id>/timelines/<timeline-id>
+Host: epufs.svc.neon.local
+
+<<<
+
+200 OK
+{
+  "tenant": "<tenant-id>",
+  "timeline": "<timeline-id>",
+  "deleted": {
+    "files": <count>,
+    "bytes": <count>,
+  },
+}
+```
+
+```http
+DELETE /tenants/<tenant-id>
+Host: epufs.svc.neon.local
+
+<<<
+
+200 OK
+{
+  "tenant": "<tenant-id>",
+  "deleted": {
+    "files": <count>,
+    "bytes": <count>,
+  },
+}
+```
+
+```mermaid
+sequenceDiagram
+    autonumber
+    participant cp as Control Plane
+    participant ep as EPUFS
+    participant s3 as Blob Storage
+
+    alt Tenant deleted
+        cp-)ep: Tenant deleted
+        loop For every object associated with removed tenant
+            ep->>s3: Remove data of deleted tenant from Storage
+        end
+        opt
+            ep-)cp: Tenant cleanup complete
+        end
+    alt Timeline deleted
+        cp-)ep: Timeline deleted
+        loop For every object associated with removed timeline
+            ep->>s3: Remove data of deleted timeline from Storage
+        end
+        opt
+            ep-)cp: Timeline cleanup complete
+        end
+    else Endpoint reassigned or removed
+        cp->>+ep: Endpoint reassigned
+        loop For every object associated with reassigned/removed endpoint
+            ep->>s3: Remove data from Storage
+        end
+        ep->>-cp: Cleanup complete
+    end
+```
+
+### Scalability (if relevant)
+
+Provisionally:  As this service is going to be part of compute startup, this
+service should be able to quickly respond to all requests.  Therefore this
+service is deployed to every AZ we host Computes in, and Computes communicate
+(generally) only to the EPUFS endpoint of the AZ they're hosted in.
+
+Local caching of frequently restarted endpoints' data or metadata may be
+needed for best performance.  However, due to the regional nature of stored
+data but zonal nature of the service deployment, we should be careful when we
+implement any local caching, as it is possible that computes in AZ 1 will
+update data originally written and thus cached by AZ 2.  Cache version tests
+and invalidation is therefore required if we want to roll out caching to this
+service, which is too broad a scope for an MVC.  This is why caching is left
+out of scope for this RFC, and should be considered separately after this RFC
+is implemented.
+
+### Security implications (if relevant)
+This service must be able to authenticate users at least by Tenant ID,
+Timeline ID and Endpoint ID. This will use the existing JWT infrastructure of
+Compute, which will be upgraded to the extent needed to support Timeline- and
+Endpoint-based claims.
+
+The service requires unlimited access to (a prefix of) a blob storage bucket,
+and thus must be hosted outside the Compute VM sandbox.
+
+A service that generates pre-signed request URLs for Compute to download the
+data from that URL is likely problematic, too:  Compute would be able to write
+unlimited data to the bucket, or exfiltrate this signed URL to get read/write
+access to specific objects in this bucket, which would still effectively give
+users access to the S3 bucket (but with improved access logging).
+
+There may be a use case for transferring data associated with one endpoint to
+another endpoint (e.g. to make one endpoint warm its caches with the state of
+another endpoint), but that's not currently in scope, and specific needs may
+be solved through out-of-line communication of data or pre-signed URLs.
+
+### Unresolved questions (if relevant)
+Caching of files is not in the implementation scope of the document, but
+should at some future point be considered to maximize performance.
+
+## Alternative implementation (if relevant)
+Several ideas have come up to solve this issue:
+
+### Use AUXfile
+One prevalent idea was to WAL-log the files using our AUXfile mechanism.
+
+Benefits:
+
+ We already have this storage mechanism
+
+Demerits:
+
+- It isn't available on read replicas
+- Additional WAL will be consumed during shutdown and after the shutdown
+  checkpoint, which needs PG modifications to work without panics.
+- It increases the data we need to manage in our versioned storage, thus
+  causing higher storage costs with higher retention due to duplication at
+  the storage layer.
+
+### Sign URLs for read/write operations, instead of proxying them
+
+Benefits:
+
+ The service can be implemented with a much reduced IO budget
+
+Demerits:
+
+- Users could get access to these signed credentials
+- Not all blob storage services may implement URL signing
+
+### Give endpoints each their own directly accessed block volume
+
+Benefits:
+
+ Easier to integrate for PostgreSQL
+
+Demerits:
+
+- Little control on data size and contents
+- Potentially problematic as we'd need to store data all across the pgdata
+  directory.
+- EBS is not a good candidate
+   - Attaches in 10s of seconds, if not more; i.e. too cold to start
+   - Shared EBS volumes are a no-go, as you'd have to schedule the endpoint
+     with users of the same EBS volumes, which can't work with VM migration
+   - EBS storage costs are very high (>80$/kilotenant when using a
+     volume/tenant)
+   - EBS volumes can't be mounted across AZ boundaries
+- Bucket per endpoint is unfeasible
+   - S3 buckets are priced at $20/month per 1k, which we could better spend
+     on developers.
+   - Allocating service accounts takes time (100s of ms), and service accounts
+     are a limited resource, too; so they're not a good candidate to allocate
+     on a per-endpoint basis.
+   - Giving credentials limited to prefix has similar issues as the pre-signed
+     URL approach.
+   - Bucket DNS lookup will fill DNS caches and put pressure on DNS lookup
+     much more than our current systems would.
+- Volumes bound by hypervisor are unlikely
+   - This requires significant investment and increased software on the
+     hypervisor.
+   - It is unclear if we can attach volumes after boot, i.e. for pooled
+     instances.
+
+### Put the files into a table
+
+Benefits:
+
+ + Mostly already available in PostgreSQL
+
+Demerits:
+
+ - Uses WAL
+   - Can't be used after shutdown checkpoint
+   - Needs a RW endpoint, and table & catalog access to write to this data
+ - Gets hit with DB size limitations
+ - Depending on user acces:
+   - Inaccessible:  
+     The user doesn't have control over database size caused by
+     these systems.
+   - Accessible:  
+     The user can corrupt these files and cause the system to crash while
+     user-corrupted files are present, thus increasing on-call overhead.
+
+## Definition of Done (if relevant)
+
+This project is done if we have:
+
+- One S3 bucket equivalent per region, which stores this per-endpoint data.
+- A new service endpoint in at least every AZ, which indirectly grants
+  endpoints access to the data stored for these endpoints in these buckets.
+- Compute writes & reads temp-data at shutdown and startup, respectively, for
+  at least the pg_prewarm or lfc_prewarm state files.
+- Cleanup of endpoint data is triggered when the endpoint is deleted or is
+  detached from its current timeline.
--- a/endpoint_storage/src/app.rs
+++ b/endpoint_storage/src/app.rs
@@ -374,7 +374,7 @@ MC4CAQAwBQYDK2VwBCIEID/Drmc1AA6U/znNRWpF3zEGegOATQxfkdWxitcOMsIH
            let request = Request::builder()
                .uri(format!("/{tenant}/{timeline}/{endpoint}/sub/path/key"))
                .method(method)
-                .header("Authorization", format!("Bearer {}", token))
+                .header("Authorization", format!("Bearer {token}"))
                .body(Body::empty())
                .unwrap();
            let status = ServiceExt::ready(&mut app)
--- a/libs/compute_api/Cargo.toml
+++ b/libs/compute_api/Cargo.toml
@@ -12,6 +12,7 @@ jsonwebtoken.workspace = true
 serde.workspace = true
 serde_json.workspace = true
 regex.workspace = true
+url.workspace = true

 utils = { path = "../utils" }
 remote_storage = { version = "0.1", path = "../remote_storage/" }
--- a/libs/compute_api/src/spec.rs
+++ b/libs/compute_api/src/spec.rs
@@ -6,10 +6,12 @@
 use std::collections::HashMap;
 use std::fmt::Display;

+use anyhow::anyhow;
 use indexmap::IndexMap;
 use regex::Regex;
 use remote_storage::RemotePath;
 use serde::{Deserialize, Serialize};
+use url::Url;
 use utils::id::{TenantId, TimelineId};
 use utils::lsn::Lsn;

@@ -182,6 +184,11 @@ pub struct ComputeSpec {
    /// Download LFC state from endpoint_storage and pass it to Postgres on startup
    #[serde(default)]
    pub autoprewarm: bool,
+
+    /// Suspend timeout in seconds.
+    ///
+    /// We use this value to derive other values, such as the installed extensions metric.
+    pub suspend_timeout_seconds: i64,
 }

 /// Feature flag to signal `compute_ctl` to enable certain experimental functionality.
@@ -320,12 +327,6 @@ impl ComputeMode {
    }
 }

-impl Display for ComputeMode {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        f.write_str(self.to_type_str())
-    }
-}
-
 /// Log level for audit logging
 #[derive(Clone, Debug, Default, Eq, PartialEq, Deserialize, Serialize)]
 pub enum ComputeAudit {
@@ -436,6 +437,47 @@ pub struct JwksSettings {
    pub jwt_audience: Option<String>,
 }

+/// Protocol used to connect to a Pageserver. Parsed from the connstring scheme.
+#[derive(Clone, Copy, Debug, Default)]
+pub enum PageserverProtocol {
+    /// The original protocol based on libpq and COPY. Uses postgresql:// or postgres:// scheme.
+    #[default]
+    Libpq,
+    /// A newer, gRPC-based protocol. Uses grpc:// scheme.
+    Grpc,
+}
+
+impl PageserverProtocol {
+    /// Parses the protocol from a connstring scheme. Defaults to Libpq if no scheme is given.
+    /// Errors if the connstring is an invalid URL.
+    pub fn from_connstring(connstring: &str) -> anyhow::Result<Self> {
+        let scheme = match Url::parse(connstring) {
+            Ok(url) => url.scheme().to_lowercase(),
+            Err(url::ParseError::RelativeUrlWithoutBase) => return Ok(Self::default()),
+            Err(err) => return Err(anyhow!("invalid connstring URL: {err}")),
+        };
+        match scheme.as_str() {
+            "postgresql" | "postgres" => Ok(Self::Libpq),
+            "grpc" => Ok(Self::Grpc),
+            scheme => Err(anyhow!("invalid protocol scheme: {scheme}")),
+        }
+    }
+
+    /// Returns the URL scheme for the protocol, for use in connstrings.
+    pub fn scheme(&self) -> &'static str {
+        match self {
+            Self::Libpq => "postgresql",
+            Self::Grpc => "grpc",
+        }
+    }
+}
+
+impl Display for PageserverProtocol {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_str(self.scheme())
+    }
+}
+
 #[cfg(test)]
 mod tests {
    use std::fs::File;
--- a/libs/compute_api/tests/cluster_spec.json
+++ b/libs/compute_api/tests/cluster_spec.json
@@ -3,6 +3,7 @@

    "timestamp": "2021-05-23T18:25:43.511Z",
    "operation_uuid": "0f657b36-4b0f-4a2d-9c2e-1dcd615e7d8b",
+    "suspend_timeout_seconds": 3600,

    "cluster": {
        "cluster_id": "test-cluster-42",
--- a/libs/desim/src/executor.rs
+++ b/libs/desim/src/executor.rs
@@ -71,7 +71,7 @@ impl Runtime {
                    debug!("thread panicked: {:?}", e);
                    let mut result = ctx.result.lock();
                    if result.0 == -1 {
-                        *result = (256, format!("thread panicked: {:?}", e));
+                        *result = (256, format!("thread panicked: {e:?}"));
                    }
                });
            }
--- a/libs/desim/src/proto.rs
+++ b/libs/desim/src/proto.rs
@@ -47,8 +47,8 @@ impl Debug for AnyMessage {
        match self {
            AnyMessage::None => write!(f, "None"),
            AnyMessage::InternalConnect => write!(f, "InternalConnect"),
-            AnyMessage::Just32(v) => write!(f, "Just32({})", v),
-            AnyMessage::ReplCell(v) => write!(f, "ReplCell({:?})", v),
+            AnyMessage::Just32(v) => write!(f, "Just32({v})"),
+            AnyMessage::ReplCell(v) => write!(f, "ReplCell({v:?})"),
            AnyMessage::Bytes(v) => write!(f, "Bytes({})", hex::encode(v)),
            AnyMessage::LSN(v) => write!(f, "LSN({})", Lsn(*v)),
        }
--- a/libs/http-utils/src/endpoint.rs
+++ b/libs/http-utils/src/endpoint.rs
@@ -582,14 +582,14 @@ pub fn attach_openapi_ui(
                            deepLinking: true,
                            showExtensions: true,
                            showCommonExtensions: true,
-                            url: "{}",
+                            url: "{spec_mount_path}",
                        }})
                        window.ui = ui;
                    }};
                </script>
                </body>
                </html>
-            "#, spec_mount_path))).unwrap())
+            "#))).unwrap())
             })
        )
 }
@@ -696,7 +696,7 @@ mod tests {
        let remote_addr = SocketAddr::new(IpAddr::from_str("127.0.0.1").unwrap(), 80);
        let mut service = builder.build(remote_addr);
        if let Err(e) = poll_fn(|ctx| service.poll_ready(ctx)).await {
-            panic!("request service is not ready: {:?}", e);
+            panic!("request service is not ready: {e:?}");
        }

        let mut req: Request<Body> = Request::default();
@@ -716,7 +716,7 @@ mod tests {
        let remote_addr = SocketAddr::new(IpAddr::from_str("127.0.0.1").unwrap(), 80);
        let mut service = builder.build(remote_addr);
        if let Err(e) = poll_fn(|ctx| service.poll_ready(ctx)).await {
-            panic!("request service is not ready: {:?}", e);
+            panic!("request service is not ready: {e:?}");
        }

        let req: Request<Body> = Request::default();
--- a/libs/neon-shmem/Cargo.toml
+++ b/libs/neon-shmem/Cargo.toml
@@ -6,27 +6,8 @@ license.workspace = true

 [dependencies]
 thiserror.workspace = true
-nix.workspace = true
+nix.workspace=true
 workspace_hack = { version = "0.1", path = "../../workspace_hack" }
-rustc-hash = { version = "2.1.1" }
-rand = "0.9.1"
-libc.workspace = true
-lock_api = "0.4.13"
-
-[dev-dependencies]
-criterion = { workspace = true, features = ["html_reports"] }
-rand_distr = "0.5.1"
-xxhash-rust = { version = "0.8.15", features = ["xxh3"] }
-ahash.workspace = true
-twox-hash = { version = "2.1.1" }
-seahash = "4.1.0"
-hashbrown = { git = "https://github.com/quantumish/hashbrown.git", rev = "6610e6d" }
-foldhash = "0.1.5"
-

 [target.'cfg(target_os = "macos")'.dependencies]
 tempfile = "3.14.0"
-
-[[bench]]
-name = "hmap_resize"
-harness = false
--- a/libs/neon-shmem/benches/hmap_resize.rs
+++ b/libs/neon-shmem/benches/hmap_resize.rs
@@ -1,282 +0,0 @@
-use criterion::{criterion_group, criterion_main, BatchSize, Criterion, BenchmarkId};
-use neon_shmem::hash::HashMapAccess;
-use neon_shmem::hash::HashMapInit;
-use neon_shmem::hash::entry::Entry;
-use rand::prelude::*;
-use rand::distr::{Distribution, StandardUniform};
-use std::hash::BuildHasher;
-use std::default::Default;
-	
-// Taken from bindings to C code
-
-#[derive(Clone, Debug, Hash, Eq, PartialEq)]
-#[repr(C)]
-pub struct FileCacheKey {
-    pub _spc_id: u32,
-    pub _db_id: u32,
-    pub _rel_number: u32,
-    pub _fork_num: u32,
-    pub _block_num: u32,
-}
-
-impl Distribution<FileCacheKey> for StandardUniform {
-	// questionable, but doesn't need to be good randomness
-	fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> FileCacheKey {
-		FileCacheKey {
-			_spc_id: rng.random(),
-			_db_id: rng.random(),
-			_rel_number: rng.random(),
-			_fork_num: rng.random(),
-			_block_num: rng.random()
-		}
-    }
-}
-
-#[derive(Clone, Debug)]
-#[repr(C)]
-pub struct FileCacheEntry {
-    pub _offset: u32,
-    pub _access_count: u32,
-    pub _prev: *mut FileCacheEntry,
-    pub _next: *mut FileCacheEntry,
-    pub _state: [u32; 8],
-}
-
-impl FileCacheEntry {
-	fn dummy() -> Self {
-		Self {
-			_offset: 0,
-			_access_count: 0,
-			_prev: std::ptr::null_mut(),
-			_next: std::ptr::null_mut(),
-			_state: [0; 8]				
-		}
-	}
-}
-
-// Utilities for applying operations.
-
-#[derive(Clone, Debug)]
-struct TestOp<K,V>(K, Option<V>);
-
-fn apply_op<K: Clone + std::hash::Hash + Eq, V, S: std::hash::BuildHasher>(
-    op: TestOp<K,V>,
-    map: &mut HashMapAccess<K,V,S>,
-) {
-	let entry = map.entry(op.0);
-
-    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,
-			}
-		},
-	};
-}
-
-// Hash utilities
-
-struct SeaRandomState {
-	k1: u64,
-	k2: u64,
-	k3: u64,
-	k4: u64 
-}
-
-impl std::hash::BuildHasher for SeaRandomState {
-	type Hasher = seahash::SeaHasher;
-	
-	fn build_hasher(&self) -> Self::Hasher {
-		seahash::SeaHasher::with_seeds(self.k1, self.k2, self.k3, self.k4)
-	}
-}
-
-impl SeaRandomState {
-	fn new() -> Self {
-		let mut rng = rand::rng();
-		Self { k1: rng.random(), k2: rng.random(), k3: rng.random(), k4: rng.random() }
-	}
-}
-
-fn small_benchs(c: &mut Criterion) {
-	let mut group = c.benchmark_group("Small maps");
-    group.sample_size(10);
-        
-	group.bench_function("small_rehash", |b| {
-		let ideal_filled = 4_000_000;
-		let size = 5_000_000;
-		let mut writer = HashMapInit::new_resizeable(size, size * 2).attach_writer();
-		let mut rng = rand::rng();		
-		while writer.get_num_buckets_in_use() < ideal_filled as usize {
-			let key: FileCacheKey = rng.random();
-			let val = FileCacheEntry::dummy();
-			apply_op(TestOp(key, Some(val)), &mut writer);
-		}
-		b.iter(|| writer.shuffle());
-	});
-	
-
-	group.bench_function("small_rehash_xxhash", |b| {
-		let ideal_filled = 4_000_000;
-		let size = 5_000_000;
-		let mut writer = HashMapInit::new_resizeable(size, size * 2)
-			.with_hasher(twox_hash::xxhash64::RandomState::default())
-			.attach_writer();
-		let mut rng = rand::rng();		
-		while writer.get_num_buckets_in_use() < ideal_filled as usize {
-			let key: FileCacheKey = rng.random();
-			let val = FileCacheEntry::dummy();
-			apply_op(TestOp(key, Some(val)), &mut writer);
-		}
-		b.iter(|| writer.shuffle());
-	});
-
-	
-	group.bench_function("small_rehash_ahash", |b| {
-		let ideal_filled = 4_000_000;
-		let size = 5_000_000;
-		let mut writer = HashMapInit::new_resizeable(size, size * 2)
-			.with_hasher(ahash::RandomState::default())
-			.attach_writer();
-		let mut rng = rand::rng();		
-		while writer.get_num_buckets_in_use() < ideal_filled as usize {
-			let key: FileCacheKey = rng.random();
-			let val = FileCacheEntry::dummy();
-			apply_op(TestOp(key, Some(val)), &mut writer);
-		}
-		b.iter(|| writer.shuffle());
-	});
-
-	group.bench_function("small_rehash_seahash", |b| {
-		let ideal_filled = 4_000_000;
-		let size = 5_000_000;
-		let mut writer = HashMapInit::new_resizeable(size, size * 2)
-			.with_hasher(SeaRandomState::new())
-			.attach_writer();
-		let mut rng = rand::rng();
-		while writer.get_num_buckets_in_use() < ideal_filled as usize {
-			let key: FileCacheKey = rng.random();
-			let val = FileCacheEntry::dummy();
-			apply_op(TestOp(key, Some(val)), &mut writer);
-		}
-		b.iter(|| writer.shuffle());
-	});
-
-	group.finish();	
-}
-
-fn real_benchs(c: &mut Criterion) {
-	let mut group = c.benchmark_group("Realistic workloads");
-	group.sample_size(10);	
-    group.bench_function("real_bulk_insert", |b| {
-		let size = 125_000_000;
-		let ideal_filled = 100_000_000;		
-		let mut rng = rand::rng();		
-		b.iter_batched(
-			|| HashMapInit::new_resizeable(size, size * 2).attach_writer(),
-			|writer| {
-				for _ in 0..ideal_filled {
-					let key: FileCacheKey = rng.random();
-					let val = FileCacheEntry::dummy();
-					let entry = writer.entry(key);
-					std::hint::black_box(match entry {
-						Entry::Occupied(mut e) => { e.insert(val); },
-						Entry::Vacant(e) => { _ = e.insert(val).unwrap(); },
-					})
-				}	
-			},
-			BatchSize::SmallInput,
-		)
-	});
-
-	group.bench_function("real_rehash", |b| {
-		let size = 125_000_000;
-		let ideal_filled = 100_000_000;		
-		let mut writer = HashMapInit::new_resizeable(size, size).attach_writer();
-		let mut rng = rand::rng();		
-		while writer.get_num_buckets_in_use() < ideal_filled {
-			let key: FileCacheKey = rng.random();
-			let val = FileCacheEntry::dummy();
-			apply_op(TestOp(key, Some(val)), &mut writer);
-		}
-		b.iter(|| writer.shuffle());
-	});
-	
-	group.bench_function("real_rehash_hashbrown", |b| {
-		let size = 125_000_000;
-		let ideal_filled = 100_000_000;
-		let mut writer = hashbrown::raw::RawTable::new();
-		let mut rng = rand::rng();
-		let hasher = rustc_hash::FxBuildHasher::default();
-		unsafe {
-			writer.resize(size, |(k,_)| hasher.hash_one(&k),
-						  hashbrown::raw::Fallibility::Infallible).unwrap();
-		}
-		while writer.len() < ideal_filled as usize {
-			let key: FileCacheKey = rng.random();
-			let val = FileCacheEntry::dummy();
-			writer.insert(hasher.hash_one(&key), (key, val), |(k,_)| hasher.hash_one(&k));
-		}
-		b.iter(|| unsafe { writer.table.rehash_in_place(
-			&|table, index| hasher.hash_one(&table.bucket::<(FileCacheKey, FileCacheEntry)>(index).as_ref().0),
-			std::mem::size_of::<(FileCacheKey, FileCacheEntry)>(),
-            if std::mem::needs_drop::<(FileCacheKey, FileCacheEntry)>() {
-                Some(|ptr| std::ptr::drop_in_place(ptr as *mut (FileCacheKey, FileCacheEntry)))
-            } else {
-                None
-            },
-		) });
-	});
-
-	for elems in [2, 4, 8, 16, 32, 64, 96, 112] {
-		group.bench_with_input(BenchmarkId::new("real_rehash_varied", elems), &elems, |b, &size| {
-			let ideal_filled = size * 1_000_000;
-			let size = 125_000_000;
-			let mut writer = HashMapInit::new_resizeable(size, size).attach_writer();
-			let mut rng = rand::rng();		
-			while writer.get_num_buckets_in_use() < ideal_filled as usize {
-				let key: FileCacheKey = rng.random();
-				let val = FileCacheEntry::dummy();
-				apply_op(TestOp(key, Some(val)), &mut writer);
-			}
-			b.iter(|| writer.shuffle());
-		});
-		group.bench_with_input(BenchmarkId::new("real_rehash_varied_hashbrown", elems), &elems, |b, &size| {
-			let ideal_filled = size * 1_000_000;
-			let size = 125_000_000;
-			let mut writer = hashbrown::raw::RawTable::new();
-			let mut rng = rand::rng();
-			let hasher = rustc_hash::FxBuildHasher::default();
-			unsafe {
-				writer.resize(size, |(k,_)| hasher.hash_one(&k),
-							  hashbrown::raw::Fallibility::Infallible).unwrap();
-			}
-			while writer.len() < ideal_filled as usize {
-				let key: FileCacheKey = rng.random();
-				let val = FileCacheEntry::dummy();
-				writer.insert(hasher.hash_one(&key), (key, val), |(k,_)| hasher.hash_one(&k));
-			}
-			b.iter(|| unsafe { writer.table.rehash_in_place(
-				&|table, index| hasher.hash_one(&table.bucket::<(FileCacheKey, FileCacheEntry)>(index).as_ref().0),
-				std::mem::size_of::<(FileCacheKey, FileCacheEntry)>(),
-				if std::mem::needs_drop::<(FileCacheKey, FileCacheEntry)>() {
-					Some(|ptr| std::ptr::drop_in_place(ptr as *mut (FileCacheKey, FileCacheEntry)))
-				} else {
-					None
-				},
-			) });
-		});
-	}
-	
-	group.finish();
-}
-	
-criterion_group!(benches, small_benchs, real_benchs);
-criterion_main!(benches);
--- a/libs/neon-shmem/src/hash.rs
+++ b/libs/neon-shmem/src/hash.rs
@@ -1,533 +0,0 @@
-//! 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.
-
-use std::hash::{Hash, BuildHasher};
-use std::mem::MaybeUninit;
-
-use crate::{shmem, sync::*};
-use crate::shmem::ShmemHandle;
-
-mod core;
-pub mod entry;
-
-#[cfg(test)]
-mod tests;
-
-use core::{Bucket, CoreHashMap, INVALID_POS};
-use entry::{Entry, OccupiedEntry, VacantEntry, PrevPos};
-
-/// Builder for a [`HashMapAccess`].
-#[must_use]
-pub struct HashMapInit<'a, K, V, S = rustc_hash::FxBuildHasher> {
-    shmem_handle: Option<ShmemHandle>,
-    shared_ptr: *mut RwLock<HashMapShared<'a, K, V>>,
-	shared_size: usize,
-	hasher: S,
-	num_buckets: u32,
-}
-
-/// Accessor for a hash table. 
-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> {
-	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
-    }
-
-	/// Initialize a table for writing.
-    pub fn attach_writer(self) -> HashMapAccess<'a, K, V, S> {
-        let mut ptr: *mut u8 = self.shared_ptr.cast();
-        let end_ptr: *mut u8 = unsafe { ptr.add(self.shared_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>>() * self.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(), self.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);
-		let lock = RwLock::from_raw(PthreadRwLock::new(raw_lock_ptr.cast()), hashmap);
-		unsafe {
-			std::ptr::write(shared_ptr, lock);
-		}
-		
-        HashMapAccess {
-            shmem_handle: self.shmem_handle,
-            shared_ptr,
-			hasher: self.hasher,
-        }
-    }
-
-	/// Initialize a table for reading. Currently identical to [`HashMapInit::attach_writer`].
-    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 {
-			num_buckets,
-			shmem_handle: None,
-			shared_ptr: area.as_mut_ptr().cast(),
-			shared_size: area.len(),
-			hasher: 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");
-		Self {
-			num_buckets,
-			shared_ptr: shmem.data_ptr.as_ptr().cast(),
-			shmem_handle: Some(shmem),
-			shared_size: size,
-			hasher: 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");
-		
-		Self {
-			num_buckets,
-			shared_ptr: shmem.data_ptr.as_ptr().cast(),
-			shmem_handle: Some(shmem),
-			shared_size: size,
-			hasher: 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.
-    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.
-	/// - Calling this function on a map with `shrink_mode` set to [`HashMapShrinkMode::Remap`] and
-	///   there are more buckets in use than the value returned by [`HashMapAccess::shrink_goal`].
-	///
-	/// # Errors
-	/// Returns an [`shmem::Error`] if any errors occur resizing the memory region.
-	pub fn finish_shrink(&self) -> Result<(), shmem::Error> {
-		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 let Some((k, v)) = map.buckets[i].inner.take() {
-				// alloc_bucket increases count, so need to decrease since we're just moving
-				map.buckets_in_use -= 1;
-				map.alloc_bucket(k, v).unwrap();
-			}
-		}
-
-        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);
-        shmem_handle.set_size(size_bytes)?;
-        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(())
-	}
-}
--- a/libs/neon-shmem/src/hash/core.rs
+++ b/libs/neon-shmem/src/hash/core.rs
@@ -1,177 +0,0 @@
-//! 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,
-	// pub(crate) lock: libc::pthread_mutex_t,
-	// Unclear what the purpose of this is.
-    pub(crate) _user_list_head: 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,
-            _user_list_head: INVALID_POS,
-			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)
-    }
-}
-
--- a/libs/neon-shmem/src/hash/entry.rs
+++ b/libs/neon-shmem/src/hash/entry.rs
@@ -1,139 +0,0 @@
-//! 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.
-	///
-	/// # Panics
-	/// Panics if the `prev_pos` field is equal to [`PrevPos::Unknown`]. In practice, this means
-	/// the entry was obtained via calling something like [`CoreHashMap::entry_at_bucket`].
-    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 {
-				curr = self.map.buckets[curr as usize].next;
-				prev = PrevPos::Chained(curr);
-			}
-			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) => {
-				// println!("we think prev of {} is {bucket_pos}", self.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)?;
-        if pos == INVALID_POS {
-            return Err(FullError());
-        }
-        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
-		))
-    }
-}
--- a/libs/neon-shmem/src/hash/tests.rs
+++ b/libs/neon-shmem/src/hash/tests.rs
@@ -1,426 +0,0 @@
-use std::collections::BTreeMap;
-use std::collections::HashSet;
-use std::fmt::Debug;
-use std::mem::MaybeUninit;
-
-use crate::hash::HashMapAccess;
-use crate::hash::HashMapInit;
-use crate::hash::Entry;
-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.get(&key).is_some() {
-                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>,
-	to: u32
-) {
-	assert!(writer.shrink_goal().is_none());
-	writer.begin_shrink(to);
-	assert_eq!(writer.shrink_goal(), Some(to as usize));
-	while writer.get_num_buckets_in_use() > to as usize {
-		let (k, _) = shadow.pop_first().unwrap();
-		let entry = writer.entry(k);
-		if let Entry::Occupied(e) = entry {
-			e.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, 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, 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, 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());
-			let pos = e.bucket_pos as usize;
-			pos
-		},
-		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);
-}
--- a/libs/neon-shmem/src/lib.rs
+++ b/libs/neon-shmem/src/lib.rs
@@ -1,5 +1,418 @@
 //! Shared memory utilities for neon communicator

-pub mod hash;
-pub mod shmem;
-pub mod sync;
+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();
+        }
+    }
+}
--- a/libs/neon-shmem/src/shmem.rs
+++ b/libs/neon-shmem/src/shmem.rs
@@ -1,418 +0,0 @@
-//! 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();
-        }
-    }
-}
--- a/libs/neon-shmem/src/sync.rs
+++ b/libs/neon-shmem/src/sync.rs
@@ -1,105 +0,0 @@
-//! 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(crate) 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>>);
-
-impl PthreadRwLock {
-	pub fn new(lock: *mut libc::pthread_rwlock_t) -> Self {
-		unsafe {
-			let mut attrs = MaybeUninit::uninit();
-			// Ignoring return value here - only possible error is OOM.
-			libc::pthread_rwlockattr_init(attrs.as_mut_ptr());
-			libc::pthread_rwlockattr_setpshared(
-				attrs.as_mut_ptr(),
-				libc::PTHREAD_PROCESS_SHARED
-			);
-			// TODO(quantumish): worth making this function return Result?
-			libc::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::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 RawMutex::INIT"),
-			Some(x) => x,
-		}
-	}
-}
-
-unsafe impl lock_api::RawRwLock for PthreadRwLock {
-	type GuardMarker = lock_api::GuardSend;
-	const INIT: Self = Self(None);	
-	
-	fn lock_shared(&self) {
-		unsafe {
-			let res = libc::pthread_rwlock_rdlock(self.inner().as_ptr());
-			if res != 0 {
-				panic!("rdlock failed with {}", Errno::from_raw(res));
-			}
-		}
-	}
-
-	fn try_lock_shared(&self) -> bool {
-		unsafe {
-			let res = libc::pthread_rwlock_tryrdlock(self.inner().as_ptr());
-			match res {
-				0 => true,
-				libc::EAGAIN => false,
-				o => panic!("try_rdlock failed with {}", Errno::from_raw(res)),
-			}
-		}
-	}
-
-	fn lock_exclusive(&self) {
-		unsafe {
-			let res = libc::pthread_rwlock_wrlock(self.inner().as_ptr());
-			if res != 0 {
-				panic!("wrlock 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,
-				o => panic!("try_wrlock failed with {}", Errno::from_raw(res)),
-			}
-		}
-	}
-
-	unsafe fn unlock_exclusive(&self) {
-		unsafe { 
-			let res = libc::pthread_rwlock_unlock(self.inner().as_ptr());
-			if res != 0 {
-				panic!("unlock failed with {}", Errno::from_raw(res));
-			}
-		}
-	}
-	unsafe fn unlock_shared(&self) {
-		unsafe {
-			let res = libc::pthread_rwlock_unlock(self.inner().as_ptr());
-			if res != 0 {
-				panic!("unlock failed with {}", Errno::from_raw(res));
-			}
-		}
-	}
-}
--- a/libs/neonart/Cargo.toml
+++ b/libs/neonart/Cargo.toml
@@ -1,14 +0,0 @@
-[package]
-name = "neonart"
-version = "0.1.0"
-edition.workspace = true
-license.workspace = true
-
-[dependencies]
-crossbeam-utils.workspace = true
-spin.workspace = true
-tracing.workspace = true
-
-[dev-dependencies]
-rand = "0.9.1"
-rand_distr = "0.5.1"
--- a/libs/neonart/src/algorithm.rs
+++ b/libs/neonart/src/algorithm.rs
@@ -1,594 +0,0 @@
-mod lock_and_version;
-pub(crate) mod node_ptr;
-mod node_ref;
-
-use std::vec::Vec;
-
-use crate::algorithm::lock_and_version::ConcurrentUpdateError;
-use crate::algorithm::node_ptr::MAX_PREFIX_LEN;
-use crate::algorithm::node_ref::{NewNodeRef, NodeRef, ReadLockedNodeRef, WriteLockedNodeRef};
-use crate::allocator::OutOfMemoryError;
-
-use crate::TreeWriteGuard;
-use crate::UpdateAction;
-use crate::allocator::ArtAllocator;
-use crate::epoch::EpochPin;
-use crate::{Key, Value};
-
-pub(crate) type RootPtr<V> = node_ptr::NodePtr<V>;
-
-#[derive(Debug)]
-pub enum ArtError {
-    ConcurrentUpdate, // need to retry
-    OutOfMemory,
-}
-
-impl From<ConcurrentUpdateError> for ArtError {
-    fn from(_: ConcurrentUpdateError) -> ArtError {
-        ArtError::ConcurrentUpdate
-    }
-}
-
-impl From<OutOfMemoryError> for ArtError {
-    fn from(_: OutOfMemoryError) -> ArtError {
-        ArtError::OutOfMemory
-    }
-}
-
-pub fn new_root<V: Value>(
-    allocator: &impl ArtAllocator<V>,
-) -> Result<RootPtr<V>, OutOfMemoryError> {
-    node_ptr::new_root(allocator)
-}
-
-pub(crate) fn search<'e, K: Key, V: Value>(
-    key: &K,
-    root: RootPtr<V>,
-    epoch_pin: &'e EpochPin,
-) -> Option<&'e V> {
-    loop {
-        let root_ref = NodeRef::from_root_ptr(root);
-        if let Ok(result) = lookup_recurse(key.as_bytes(), root_ref, None, epoch_pin) {
-            break result;
-        }
-        // retry
-    }
-}
-
-pub(crate) fn iter_next<'e, V: Value>(
-    key: &[u8],
-    root: RootPtr<V>,
-    epoch_pin: &'e EpochPin,
-) -> Option<(Vec<u8>, &'e V)> {
-    loop {
-        let mut path = Vec::new();
-        let root_ref = NodeRef::from_root_ptr(root);
-
-        match next_recurse(key, &mut path, root_ref, epoch_pin) {
-            Ok(Some(v)) => {
-                assert_eq!(path.len(), key.len());
-                break Some((path, v));
-            }
-            Ok(None) => break None,
-            Err(ConcurrentUpdateError()) => {
-                // retry
-                continue;
-            }
-        }
-    }
-}
-
-pub(crate) fn update_fn<'e, 'g, K: Key, V: Value, A: ArtAllocator<V>, F>(
-    key: &K,
-    value_fn: F,
-    root: RootPtr<V>,
-    guard: &'g mut TreeWriteGuard<'e, K, V, A>,
-) -> Result<(), OutOfMemoryError>
-where
-    F: FnOnce(Option<&V>) -> UpdateAction<V>,
-{
-    let value_fn_cell = std::cell::Cell::new(Some(value_fn));
-    loop {
-        let root_ref = NodeRef::from_root_ptr(root);
-        let this_value_fn = |arg: Option<&V>| value_fn_cell.take().unwrap()(arg);
-        let key_bytes = key.as_bytes();
-
-        match update_recurse(
-            key_bytes,
-            this_value_fn,
-            root_ref,
-            None,
-            None,
-            guard,
-            0,
-            key_bytes,
-        ) {
-            Ok(()) => break Ok(()),
-            Err(ArtError::ConcurrentUpdate) => {
-                continue; // retry
-            }
-            Err(ArtError::OutOfMemory) => break Err(OutOfMemoryError()),
-        }
-    }
-}
-
-// Error means you must retry.
-//
-// This corresponds to the 'lookupOpt' function in the paper
-fn lookup_recurse<'e, V: Value>(
-    key: &[u8],
-    node: NodeRef<'e, V>,
-    parent: Option<ReadLockedNodeRef<V>>,
-    epoch_pin: &'e EpochPin,
-) -> Result<Option<&'e V>, ConcurrentUpdateError> {
-    let rnode = node.read_lock_or_restart()?;
-    if let Some(parent) = parent {
-        parent.read_unlock_or_restart()?;
-    }
-
-    // check if the prefix matches, may increment level
-    let prefix_len = if let Some(prefix_len) = rnode.prefix_matches(key) {
-        prefix_len
-    } else {
-        rnode.read_unlock_or_restart()?;
-        return Ok(None);
-    };
-
-    if rnode.is_leaf() {
-        assert_eq!(key.len(), prefix_len);
-        let vptr = rnode.get_leaf_value_ptr()?;
-        // safety: It's OK to return a ref of the pointer because we checked the version
-        // and the lifetime of 'epoch_pin' enforces that the reference is only accessible
-        // as long as the epoch is pinned.
-        let v = unsafe { vptr.as_ref().unwrap() };
-        return Ok(Some(v));
-    }
-
-    let key = &key[prefix_len..];
-
-    // find child (or leaf value)
-    let next_node = rnode.find_child_or_restart(key[0])?;
-
-    match next_node {
-        None => Ok(None), // key not found
-        Some(child) => lookup_recurse(&key[1..], child, Some(rnode), epoch_pin),
-    }
-}
-
-fn next_recurse<'e, V: Value>(
-    min_key: &[u8],
-    path: &mut Vec<u8>,
-    node: NodeRef<'e, V>,
-    epoch_pin: &'e EpochPin,
-) -> Result<Option<&'e V>, ConcurrentUpdateError> {
-    let rnode = node.read_lock_or_restart()?;
-    let prefix = rnode.get_prefix();
-    if prefix.len() != 0 {
-        path.extend_from_slice(prefix);
-    }
-
-    use std::cmp::Ordering;
-    let comparison = path.as_slice().cmp(&min_key[0..path.len()]);
-    if comparison == Ordering::Less {
-        rnode.read_unlock_or_restart()?;
-        return Ok(None);
-    }
-
-    if rnode.is_leaf() {
-        assert_eq!(path.len(), min_key.len());
-        let vptr = rnode.get_leaf_value_ptr()?;
-        // safety: It's OK to return a ref of the pointer because we checked the version
-        // and the lifetime of 'epoch_pin' enforces that the reference is only accessible
-        // as long as the epoch is pinned.
-        let v = unsafe { vptr.as_ref().unwrap() };
-        return Ok(Some(v));
-    }
-
-    let mut min_key_byte = match comparison {
-        Ordering::Less => unreachable!(), // checked this above already
-        Ordering::Equal => min_key[path.len()],
-        Ordering::Greater => 0,
-    };
-
-    loop {
-        match rnode.find_next_child_or_restart(min_key_byte)? {
-            None => {
-                return Ok(None);
-            }
-            Some((key_byte, child_ref)) => {
-                let path_len = path.len();
-                path.push(key_byte);
-                let result = next_recurse(min_key, path, child_ref, epoch_pin)?;
-                if result.is_some() {
-                    return Ok(result);
-                }
-                if key_byte == u8::MAX {
-                    return Ok(None);
-                }
-                path.truncate(path_len);
-                min_key_byte = key_byte + 1;
-            }
-        }
-    }
-}
-
-// This corresponds to the 'insertOpt' function in the paper
-pub(crate) fn update_recurse<'e, 'g, K: Key, V: Value, A: ArtAllocator<V>, F>(
-    key: &[u8],
-    value_fn: F,
-    node: NodeRef<'e, V>,
-    rparent: Option<(ReadLockedNodeRef<V>, u8)>,
-    rgrandparent: Option<(ReadLockedNodeRef<V>, u8)>,
-    guard: &'g mut TreeWriteGuard<'e, K, V, A>,
-    level: usize,
-    orig_key: &[u8],
-) -> Result<(), ArtError>
-where
-    F: FnOnce(Option<&V>) -> UpdateAction<V>,
-{
-    let rnode = node.read_lock_or_restart()?;
-
-    let prefix_match_len = rnode.prefix_matches(key);
-    if prefix_match_len.is_none() {
-        let (rparent, parent_key) = rparent.expect("direct children of the root have no prefix");
-        let mut wparent = rparent.upgrade_to_write_lock_or_restart()?;
-        let mut wnode = rnode.upgrade_to_write_lock_or_restart()?;
-
-        match value_fn(None) {
-            UpdateAction::Nothing => {}
-            UpdateAction::Insert(new_value) => {
-                insert_split_prefix(key, new_value, &mut wnode, &mut wparent, parent_key, guard)?;
-            }
-            UpdateAction::Remove => {
-                panic!("unexpected Remove action on insertion");
-            }
-        }
-        wnode.write_unlock();
-        wparent.write_unlock();
-        return Ok(());
-    }
-    let prefix_match_len = prefix_match_len.unwrap();
-    let key = &key[prefix_match_len as usize..];
-    let level = level + prefix_match_len as usize;
-
-    if rnode.is_leaf() {
-        assert_eq!(key.len(), 0);
-        let (rparent, parent_key) = rparent.expect("root cannot be leaf");
-        let mut wparent = rparent.upgrade_to_write_lock_or_restart()?;
-        let mut wnode = rnode.upgrade_to_write_lock_or_restart()?;
-
-        // safety: Now that we have acquired the write lock, we have exclusive access to the
-        // value. XXX: There might be concurrent reads though?
-        let value_mut = wnode.get_leaf_value_mut();
-
-        match value_fn(Some(value_mut)) {
-            UpdateAction::Nothing => {
-                wparent.write_unlock();
-                wnode.write_unlock();
-            }
-            UpdateAction::Insert(_) => panic!("cannot insert over existing value"),
-            UpdateAction::Remove => {
-                guard.remember_obsolete_node(wnode.as_ptr());
-                wparent.delete_child(parent_key);
-                wnode.write_unlock_obsolete();
-
-                if let Some(rgrandparent) = rgrandparent {
-                    // FIXME: Ignore concurrency error. It doesn't lead to
-                    // corruption, but it means we might leak something. Until
-                    // another update cleans it up.
-                    let _ = cleanup_parent(wparent, rgrandparent, guard);
-                }
-            }
-        }
-
-        return Ok(());
-    }
-
-    let next_node = rnode.find_child_or_restart(key[0])?;
-
-    if next_node.is_none() {
-        if rnode.is_full() {
-            let (rparent, parent_key) = rparent.expect("root node cannot become full");
-            let mut wparent = rparent.upgrade_to_write_lock_or_restart()?;
-            let wnode = rnode.upgrade_to_write_lock_or_restart()?;
-
-            match value_fn(None) {
-                UpdateAction::Nothing => {
-                    wnode.write_unlock();
-                    wparent.write_unlock();
-                }
-                UpdateAction::Insert(new_value) => {
-                    insert_and_grow(key, new_value, wnode, &mut wparent, parent_key, guard)?;
-                    wparent.write_unlock();
-                }
-                UpdateAction::Remove => {
-                    panic!("unexpected Remove action on insertion");
-                }
-            };
-        } else {
-            let mut wnode = rnode.upgrade_to_write_lock_or_restart()?;
-            if let Some((rparent, _)) = rparent {
-                rparent.read_unlock_or_restart()?;
-            }
-            match value_fn(None) {
-                UpdateAction::Nothing => {}
-                UpdateAction::Insert(new_value) => {
-                    insert_to_node(&mut wnode, key, new_value, guard)?;
-                }
-                UpdateAction::Remove => {
-                    panic!("unexpected Remove action on insertion");
-                }
-            };
-            wnode.write_unlock();
-        }
-        return Ok(());
-    } else {
-        let next_child = next_node.unwrap(); // checked above it's not None
-        if let Some((ref rparent, _)) = rparent {
-            rparent.check_or_restart()?;
-        }
-
-        // recurse to next level
-        update_recurse(
-            &key[1..],
-            value_fn,
-            next_child,
-            Some((rnode, key[0])),
-            rparent,
-            guard,
-            level + 1,
-            orig_key,
-        )
-    }
-}
-
-#[derive(Clone)]
-enum PathElement {
-    Prefix(Vec<u8>),
-    KeyByte(u8),
-}
-
-impl std::fmt::Debug for PathElement {
-    fn fmt(&self, fmt: &mut std::fmt::Formatter<'_>) -> Result<(), std::fmt::Error> {
-        match self {
-            PathElement::Prefix(prefix) => write!(fmt, "{:?}", prefix),
-            PathElement::KeyByte(key_byte) => write!(fmt, "{}", key_byte),
-        }
-    }
-}
-
-pub(crate) fn dump_tree<'e, V: Value + std::fmt::Debug>(
-    root: RootPtr<V>,
-    epoch_pin: &'e EpochPin,
-    dst: &mut dyn std::io::Write,
-) {
-    let root_ref = NodeRef::from_root_ptr(root);
-
-    let _ = dump_recurse(&[], root_ref, &epoch_pin, 0, dst);
-}
-
-// TODO: return an Err if writeln!() returns error, instead of unwrapping
-fn dump_recurse<'e, V: Value + std::fmt::Debug>(
-    path: &[PathElement],
-    node: NodeRef<'e, V>,
-    epoch_pin: &'e EpochPin,
-    level: usize,
-    dst: &mut dyn std::io::Write,
-) -> Result<(), ConcurrentUpdateError> {
-    let indent = str::repeat(" ", level);
-
-    let rnode = node.read_lock_or_restart()?;
-    let mut path = Vec::from(path);
-    let prefix = rnode.get_prefix();
-    if prefix.len() != 0 {
-        path.push(PathElement::Prefix(Vec::from(prefix)));
-    }
-
-    if rnode.is_leaf() {
-        let vptr = rnode.get_leaf_value_ptr()?;
-        // safety: It's OK to return a ref of the pointer because we checked the version
-        // and the lifetime of 'epoch_pin' enforces that the reference is only accessible
-        // as long as the epoch is pinned.
-        let val = unsafe { vptr.as_ref().unwrap() };
-        writeln!(dst, "{} {:?}: {:?}", indent, path, val).unwrap();
-        return Ok(());
-    }
-
-    for key_byte in 0..=u8::MAX {
-        match rnode.find_child_or_restart(key_byte)? {
-            None => continue,
-            Some(child_ref) => {
-                let rchild = child_ref.read_lock_or_restart()?;
-                writeln!(
-                    dst,
-                    "{} {:?}, {}: prefix {:?}",
-                    indent,
-                    &path,
-                    key_byte,
-                    rchild.get_prefix()
-                )
-                .unwrap();
-
-                let mut child_path = path.clone();
-                child_path.push(PathElement::KeyByte(key_byte));
-
-                dump_recurse(&child_path, child_ref, epoch_pin, level + 1, dst)?;
-            }
-        }
-    }
-
-    Ok(())
-}
-
-///```text
-///        [fooba]r -> value
-///
-/// [foo]b -> [a]r  -> value
-///      e -> [ls]e -> value
-///```
-fn insert_split_prefix<'e, K: Key, V: Value, A: ArtAllocator<V>>(
-    key: &[u8],
-    value: V,
-    node: &mut WriteLockedNodeRef<V>,
-    parent: &mut WriteLockedNodeRef<V>,
-    parent_key: u8,
-    guard: &'e TreeWriteGuard<K, V, A>,
-) -> Result<(), OutOfMemoryError> {
-    let old_node = node;
-    let old_prefix = old_node.get_prefix();
-    let common_prefix_len = common_prefix(key, old_prefix);
-
-    // Allocate a node for the new value.
-    let new_value_node = allocate_node_for_value(
-        &key[common_prefix_len + 1..],
-        value,
-        guard.tree_writer.allocator,
-    )?;
-
-    // Allocate a new internal node with the common prefix
-    // FIXME: deallocate 'new_value_node' on OOM
-    let mut prefix_node =
-        node_ref::new_internal(&key[..common_prefix_len], guard.tree_writer.allocator)?;
-
-    // Add the old node and the new nodes to the new internal node
-    prefix_node.insert_old_child(old_prefix[common_prefix_len], old_node);
-    prefix_node.insert_new_child(key[common_prefix_len], new_value_node);
-
-    // Modify the prefix of the old child in place
-    old_node.truncate_prefix(old_prefix.len() - common_prefix_len - 1);
-
-    // replace the pointer in the parent
-    parent.replace_child(parent_key, prefix_node.into_ptr());
-
-    Ok(())
-}
-
-fn insert_to_node<'e, K: Key, V: Value, A: ArtAllocator<V>>(
-    wnode: &mut WriteLockedNodeRef<V>,
-    key: &[u8],
-    value: V,
-    guard: &'e TreeWriteGuard<K, V, A>,
-) -> Result<(), OutOfMemoryError> {
-    let value_child = allocate_node_for_value(&key[1..], value, guard.tree_writer.allocator)?;
-    wnode.insert_child(key[0], value_child.into_ptr());
-    Ok(())
-}
-
-// On entry: 'parent' and 'node' are locked
-fn insert_and_grow<'e, 'g, K: Key, V: Value, A: ArtAllocator<V>>(
-    key: &[u8],
-    value: V,
-    wnode: WriteLockedNodeRef<V>,
-    parent: &mut WriteLockedNodeRef<V>,
-    parent_key_byte: u8,
-    guard: &'g mut TreeWriteGuard<'e, K, V, A>,
-) -> Result<(), ArtError> {
-    let mut bigger_node = wnode.grow(guard.tree_writer.allocator)?;
-
-    // FIXME: deallocate 'bigger_node' on OOM
-    let value_child = allocate_node_for_value(&key[1..], value, guard.tree_writer.allocator)?;
-    bigger_node.insert_new_child(key[0], value_child);
-
-    // Replace the pointer in the parent
-    parent.replace_child(parent_key_byte, bigger_node.into_ptr());
-
-    guard.remember_obsolete_node(wnode.as_ptr());
-    wnode.write_unlock_obsolete();
-
-    Ok(())
-}
-
-fn cleanup_parent<'e, 'g, K: Key, V: Value, A: ArtAllocator<V>>(
-    wparent: WriteLockedNodeRef<V>,
-    rgrandparent: (ReadLockedNodeRef<V>, u8),
-    guard: &'g mut TreeWriteGuard<'e, K, V, A>,
-) -> Result<(), ArtError> {
-    let (rgrandparent, grandparent_key_byte) = rgrandparent;
-
-    // If the parent becomes completely empty after the deletion, remove the parent from the
-    // grandparent. (This case is possible because we reserve only 8 bytes for the prefix.)
-    // TODO: not implemented.
-
-    // If the parent has only one child, replace the parent with the remaining child. (This is not
-    // possible if the child's prefix field cannot absorb the parent's)
-    if wparent.num_children() == 1 {
-        // Try to lock the remaining child. This can fail if the child is updated
-        // concurrently.
-        let (key_byte, remaining_child) = wparent.find_remaining_child();
-
-        let mut wremaining_child = remaining_child.write_lock_or_restart()?;
-
-        if 1 + wremaining_child.get_prefix().len() + wparent.get_prefix().len() <= MAX_PREFIX_LEN {
-            let mut wgrandparent = rgrandparent.upgrade_to_write_lock_or_restart()?;
-
-            // Ok, we have locked the leaf, the parent, the grandparent, and the parent's only
-            // remaining leaf. Proceed with the updates.
-
-            // Update the prefix on the remaining leaf
-            wremaining_child.prepend_prefix(wparent.get_prefix(), key_byte);
-
-            // Replace the pointer in the grandparent to point directly to the remaining leaf
-            wgrandparent.replace_child(grandparent_key_byte, wremaining_child.as_ptr());
-
-            // Mark the parent as deleted.
-            guard.remember_obsolete_node(wparent.as_ptr());
-            wparent.write_unlock_obsolete();
-            return Ok(());
-        }
-    }
-
-    // If the parent's children would fit on a smaller node type after the deletion, replace it with
-    // a smaller node.
-    if wparent.can_shrink() {
-        let mut wgrandparent = rgrandparent.upgrade_to_write_lock_or_restart()?;
-        let smaller_node = wparent.shrink(guard.tree_writer.allocator)?;
-
-        // Replace the pointer in the grandparent
-        wgrandparent.replace_child(grandparent_key_byte, smaller_node.into_ptr());
-
-        guard.remember_obsolete_node(wparent.as_ptr());
-        wparent.write_unlock_obsolete();
-        return Ok(());
-    }
-
-    // nothing to do
-    wparent.write_unlock();
-    Ok(())
-}
-
-// Allocate a new leaf node to hold 'value'. If the key is long, we
-// may need to allocate new internal nodes to hold it too
-fn allocate_node_for_value<'a, V: Value, A: ArtAllocator<V>>(
-    key: &[u8],
-    value: V,
-    allocator: &'a A,
-) -> Result<NewNodeRef<'a, V, A>, OutOfMemoryError> {
-    let mut prefix_off = key.len().saturating_sub(MAX_PREFIX_LEN);
-
-    let leaf_node = node_ref::new_leaf(&key[prefix_off..key.len()], value, allocator)?;
-
-    let mut node = leaf_node;
-    while prefix_off > 0 {
-        // Need another internal node
-        let remain_prefix = &key[0..prefix_off];
-
-        prefix_off = remain_prefix.len().saturating_sub(MAX_PREFIX_LEN + 1);
-        let mut internal_node = node_ref::new_internal(
-            &remain_prefix[prefix_off..remain_prefix.len() - 1],
-            allocator,
-        )?;
-        internal_node.insert_new_child(*remain_prefix.last().unwrap(), node);
-        node = internal_node;
-    }
-
-    Ok(node)
-}
-
-fn common_prefix(a: &[u8], b: &[u8]) -> usize {
-    for i in 0..MAX_PREFIX_LEN {
-        if a[i] != b[i] {
-            return i;
-        }
-    }
-    panic!("prefixes are equal");
-}
--- a/libs/neonart/src/algorithm/lock_and_version.rs
+++ b/libs/neonart/src/algorithm/lock_and_version.rs
@@ -1,117 +0,0 @@
-//! Each node in the tree has contains one atomic word that stores three things:
-//!
-//! Bit 0: set if the node is "obsolete". An obsolete node has been removed from the tree,
-//!        but might still be accessed by concurrent readers until the epoch expires.
-//! Bit 1: set if the node is currently write-locked. Used as a spinlock.
-//! Bits 2-63: Version number, incremented every time the node is modified.
-//!
-//! AtomicLockAndVersion represents that.
-
-use std::sync::atomic::{AtomicU64, Ordering};
-
-pub(crate) struct ConcurrentUpdateError();
-
-pub(crate) struct AtomicLockAndVersion {
-    inner: AtomicU64,
-}
-
-impl AtomicLockAndVersion {
-    pub(crate) fn new() -> AtomicLockAndVersion {
-        AtomicLockAndVersion {
-            inner: AtomicU64::new(0),
-        }
-    }
-}
-
-impl AtomicLockAndVersion {
-    pub(crate) fn read_lock_or_restart(&self) -> Result<u64, ConcurrentUpdateError> {
-        let version = self.await_node_unlocked();
-        if is_obsolete(version) {
-            return Err(ConcurrentUpdateError());
-        }
-        Ok(version)
-    }
-
-    pub(crate) fn check_or_restart(&self, version: u64) -> Result<(), ConcurrentUpdateError> {
-        self.read_unlock_or_restart(version)
-    }
-
-    pub(crate) fn read_unlock_or_restart(&self, version: u64) -> Result<(), ConcurrentUpdateError> {
-        if self.inner.load(Ordering::Acquire) != version {
-            return Err(ConcurrentUpdateError());
-        }
-        Ok(())
-    }
-
-    pub(crate) fn upgrade_to_write_lock_or_restart(
-        &self,
-        version: u64,
-    ) -> Result<(), ConcurrentUpdateError> {
-        if self
-            .inner
-            .compare_exchange(
-                version,
-                set_locked_bit(version),
-                Ordering::Acquire,
-                Ordering::Relaxed,
-            )
-            .is_err()
-        {
-            return Err(ConcurrentUpdateError());
-        }
-        Ok(())
-    }
-
-    pub(crate) fn write_lock_or_restart(&self) -> Result<(), ConcurrentUpdateError> {
-        let old = self.inner.load(Ordering::Relaxed);
-        if is_obsolete(old) || is_locked(old) {
-            return Err(ConcurrentUpdateError());
-        }
-        if self
-            .inner
-            .compare_exchange(
-                old,
-                set_locked_bit(old),
-                Ordering::Acquire,
-                Ordering::Relaxed,
-            )
-            .is_err()
-        {
-            return Err(ConcurrentUpdateError());
-        }
-        Ok(())
-    }
-
-    pub(crate) fn write_unlock(&self) {
-        // reset locked bit and overflow into version
-        self.inner.fetch_add(2, Ordering::Release);
-    }
-
-    pub(crate) fn write_unlock_obsolete(&self) {
-        // set obsolete, reset locked, overflow into version
-        self.inner.fetch_add(3, Ordering::Release);
-    }
-
-    // Helper functions
-    fn await_node_unlocked(&self) -> u64 {
-        let mut version = self.inner.load(Ordering::Acquire);
-        while is_locked(version) {
-            // spinlock
-            std::thread::yield_now();
-            version = self.inner.load(Ordering::Acquire)
-        }
-        version
-    }
-}
-
-fn set_locked_bit(version: u64) -> u64 {
-    return version + 2;
-}
-
-fn is_obsolete(version: u64) -> bool {
-    return (version & 1) == 1;
-}
-
-fn is_locked(version: u64) -> bool {
-    return (version & 2) == 2;
-}
--- a/libs/neonart/src/algorithm/node_ptr.rs
+++ b/libs/neonart/src/algorithm/node_ptr.rs
--- a/libs/neonart/src/algorithm/node_ref.rs
+++ b/libs/neonart/src/algorithm/node_ref.rs
@@ -1,349 +0,0 @@
-use std::fmt::Debug;
-use std::marker::PhantomData;
-
-use super::node_ptr;
-use super::node_ptr::NodePtr;
-use crate::EpochPin;
-use crate::Value;
-use crate::algorithm::lock_and_version::AtomicLockAndVersion;
-use crate::algorithm::lock_and_version::ConcurrentUpdateError;
-use crate::allocator::ArtAllocator;
-use crate::allocator::OutOfMemoryError;
-
-pub struct NodeRef<'e, V> {
-    ptr: NodePtr<V>,
-
-    phantom: PhantomData<&'e EpochPin<'e>>,
-}
-
-impl<'e, V> Debug for NodeRef<'e, V> {
-    fn fmt(&self, fmt: &mut std::fmt::Formatter<'_>) -> Result<(), std::fmt::Error> {
-        write!(fmt, "{:?}", self.ptr)
-    }
-}
-
-impl<'e, V: Value> NodeRef<'e, V> {
-    pub(crate) fn from_root_ptr(root_ptr: NodePtr<V>) -> NodeRef<'e, V> {
-        NodeRef {
-            ptr: root_ptr,
-            phantom: PhantomData,
-        }
-    }
-
-    pub(crate) fn read_lock_or_restart(
-        &self,
-    ) -> Result<ReadLockedNodeRef<'e, V>, ConcurrentUpdateError> {
-        let version = self.lockword().read_lock_or_restart()?;
-        Ok(ReadLockedNodeRef {
-            ptr: self.ptr,
-            version,
-            phantom: self.phantom,
-        })
-    }
-
-    pub(crate) fn write_lock_or_restart(
-        &self,
-    ) -> Result<WriteLockedNodeRef<'e, V>, ConcurrentUpdateError> {
-        self.lockword().write_lock_or_restart()?;
-        Ok(WriteLockedNodeRef {
-            ptr: self.ptr,
-            phantom: self.phantom,
-        })
-    }
-
-    fn lockword(&self) -> &AtomicLockAndVersion {
-        self.ptr.lockword()
-    }
-}
-
-/// A reference to a node that has been optimistically read-locked. The functions re-check
-/// the version after each read.
-pub struct ReadLockedNodeRef<'e, V> {
-    ptr: NodePtr<V>,
-    version: u64,
-
-    phantom: PhantomData<&'e EpochPin<'e>>,
-}
-
-impl<'e, V: Value> ReadLockedNodeRef<'e, V> {
-    pub(crate) fn is_leaf(&self) -> bool {
-        self.ptr.is_leaf()
-    }
-
-    pub(crate) fn is_full(&self) -> bool {
-        self.ptr.is_full()
-    }
-
-    pub(crate) fn get_prefix(&self) -> &[u8] {
-        self.ptr.get_prefix()
-    }
-
-    /// Note: because we're only holding a read lock, the prefix can change concurrently.
-    /// You must be prepared to restart, if read_unlock() returns error later.
-    ///
-    /// Returns the length of the prefix, or None if it's not a match
-    pub(crate) fn prefix_matches(&self, key: &[u8]) -> Option<usize> {
-        self.ptr.prefix_matches(key)
-    }
-
-    pub(crate) fn find_child_or_restart(
-        &self,
-        key_byte: u8,
-    ) -> Result<Option<NodeRef<'e, V>>, ConcurrentUpdateError> {
-        let child_or_value = self.ptr.find_child(key_byte);
-        self.ptr.lockword().check_or_restart(self.version)?;
-
-        match child_or_value {
-            None => Ok(None),
-            Some(child_ptr) => Ok(Some(NodeRef {
-                ptr: child_ptr,
-                phantom: self.phantom,
-            })),
-        }
-    }
-
-    pub(crate) fn find_next_child_or_restart(
-        &self,
-        min_key_byte: u8,
-    ) -> Result<Option<(u8, NodeRef<'e, V>)>, ConcurrentUpdateError> {
-        let child_or_value = self.ptr.find_next_child(min_key_byte);
-        self.ptr.lockword().check_or_restart(self.version)?;
-
-        match child_or_value {
-            None => Ok(None),
-            Some((k, child_ptr)) => Ok(Some((
-                k,
-                NodeRef {
-                    ptr: child_ptr,
-                    phantom: self.phantom,
-                },
-            ))),
-        }
-    }
-
-    pub(crate) fn get_leaf_value_ptr(&self) -> Result<*const V, ConcurrentUpdateError> {
-        let result = self.ptr.get_leaf_value();
-        self.ptr.lockword().check_or_restart(self.version)?;
-
-        // Extend the lifetime.
-        let result = std::ptr::from_ref(result);
-
-        Ok(result)
-    }
-
-    pub(crate) fn upgrade_to_write_lock_or_restart(
-        self,
-    ) -> Result<WriteLockedNodeRef<'e, V>, ConcurrentUpdateError> {
-        self.ptr
-            .lockword()
-            .upgrade_to_write_lock_or_restart(self.version)?;
-
-        Ok(WriteLockedNodeRef {
-            ptr: self.ptr,
-            phantom: self.phantom,
-        })
-    }
-
-    pub(crate) fn read_unlock_or_restart(self) -> Result<(), ConcurrentUpdateError> {
-        self.ptr.lockword().check_or_restart(self.version)?;
-        Ok(())
-    }
-
-    pub(crate) fn check_or_restart(&self) -> Result<(), ConcurrentUpdateError> {
-        self.ptr.lockword().check_or_restart(self.version)?;
-        Ok(())
-    }
-}
-
-/// A reference to a node that has been optimistically read-locked. The functions re-check
-/// the version after each read.
-pub struct WriteLockedNodeRef<'e, V> {
-    ptr: NodePtr<V>,
-    phantom: PhantomData<&'e EpochPin<'e>>,
-}
-
-impl<'e, V: Value> WriteLockedNodeRef<'e, V> {
-    pub(crate) fn can_shrink(&self) -> bool {
-        self.ptr.can_shrink()
-    }
-
-    pub(crate) fn num_children(&self) -> usize {
-        self.ptr.num_children()
-    }
-
-    pub(crate) fn write_unlock(mut self) {
-        self.ptr.lockword().write_unlock();
-        self.ptr = NodePtr::null();
-    }
-
-    pub(crate) fn write_unlock_obsolete(mut self) {
-        self.ptr.lockword().write_unlock_obsolete();
-        self.ptr = NodePtr::null();
-    }
-
-    pub(crate) fn get_prefix(&self) -> &[u8] {
-        self.ptr.get_prefix()
-    }
-
-    pub(crate) fn truncate_prefix(&mut self, new_prefix_len: usize) {
-        self.ptr.truncate_prefix(new_prefix_len)
-    }
-
-    pub(crate) fn prepend_prefix(&mut self, prefix: &[u8], prefix_byte: u8) {
-        self.ptr.prepend_prefix(prefix, prefix_byte)
-    }
-
-    pub(crate) fn insert_child(&mut self, key_byte: u8, child: NodePtr<V>) {
-        self.ptr.insert_child(key_byte, child)
-    }
-
-    pub(crate) fn get_leaf_value_mut(&mut self) -> &mut V {
-        self.ptr.get_leaf_value_mut()
-    }
-
-    pub(crate) fn grow<'a, A>(
-        &self,
-        allocator: &'a A,
-    ) -> Result<NewNodeRef<'a, V, A>, OutOfMemoryError>
-    where
-        A: ArtAllocator<V>,
-    {
-        let new_node = self.ptr.grow(allocator)?;
-        Ok(NewNodeRef {
-            ptr: new_node,
-            allocator,
-            extra_nodes: Vec::new(),
-        })
-    }
-
-    pub(crate) fn shrink<'a, A>(
-        &self,
-        allocator: &'a A,
-    ) -> Result<NewNodeRef<'a, V, A>, OutOfMemoryError>
-    where
-        A: ArtAllocator<V>,
-    {
-        let new_node = self.ptr.shrink(allocator)?;
-        Ok(NewNodeRef {
-            ptr: new_node,
-            allocator,
-            extra_nodes: Vec::new(),
-        })
-    }
-
-    pub(crate) fn as_ptr(&self) -> NodePtr<V> {
-        self.ptr
-    }
-
-    pub(crate) fn replace_child(&mut self, key_byte: u8, replacement: NodePtr<V>) {
-        self.ptr.replace_child(key_byte, replacement);
-    }
-
-    pub(crate) fn delete_child(&mut self, key_byte: u8) {
-        self.ptr.delete_child(key_byte);
-    }
-
-    pub(crate) fn find_remaining_child(&self) -> (u8, NodeRef<'e, V>) {
-        assert_eq!(self.num_children(), 1);
-        let child_or_value = self.ptr.find_next_child(0);
-
-        match child_or_value {
-            None => panic!("could not find only child in node"),
-            Some((k, child_ptr)) => (
-                k,
-                NodeRef {
-                    ptr: child_ptr,
-                    phantom: self.phantom,
-                },
-            ),
-        }
-    }
-}
-
-impl<'e, V> Drop for WriteLockedNodeRef<'e, V> {
-    fn drop(&mut self) {
-        if !self.ptr.is_null() {
-            self.ptr.lockword().write_unlock();
-        }
-    }
-}
-
-pub(crate) struct NewNodeRef<'a, V, A>
-where
-    V: Value,
-    A: ArtAllocator<V>,
-{
-    ptr: NodePtr<V>,
-    allocator: &'a A,
-
-    extra_nodes: Vec<NodePtr<V>>,
-}
-
-impl<'a, V, A> NewNodeRef<'a, V, A>
-where
-    V: Value,
-    A: ArtAllocator<V>,
-{
-    pub(crate) fn insert_old_child(&mut self, key_byte: u8, child: &WriteLockedNodeRef<V>) {
-        self.ptr.insert_child(key_byte, child.as_ptr())
-    }
-
-    pub(crate) fn into_ptr(mut self) -> NodePtr<V> {
-        let ptr = self.ptr;
-        self.ptr = NodePtr::null();
-        ptr
-    }
-
-    pub(crate) fn insert_new_child(&mut self, key_byte: u8, child: NewNodeRef<'a, V, A>) {
-        let child_ptr = child.into_ptr();
-        self.ptr.insert_child(key_byte, child_ptr);
-        self.extra_nodes.push(child_ptr);
-    }
-}
-
-impl<'a, V, A> Drop for NewNodeRef<'a, V, A>
-where
-    V: Value,
-    A: ArtAllocator<V>,
-{
-    /// This drop implementation deallocates the newly allocated node, if into_ptr() was not called.
-    fn drop(&mut self) {
-        if !self.ptr.is_null() {
-            self.ptr.deallocate(self.allocator);
-            for p in self.extra_nodes.iter() {
-                p.deallocate(self.allocator);
-            }
-        }
-    }
-}
-
-pub(crate) fn new_internal<'a, V, A>(
-    prefix: &[u8],
-    allocator: &'a A,
-) -> Result<NewNodeRef<'a, V, A>, OutOfMemoryError>
-where
-    V: Value,
-    A: ArtAllocator<V>,
-{
-    Ok(NewNodeRef {
-        ptr: node_ptr::new_internal(prefix, allocator)?,
-        allocator,
-        extra_nodes: Vec::new(),
-    })
-}
-
-pub(crate) fn new_leaf<'a, V, A>(
-    prefix: &[u8],
-    value: V,
-    allocator: &'a A,
-) -> Result<NewNodeRef<'a, V, A>, OutOfMemoryError>
-where
-    V: Value,
-    A: ArtAllocator<V>,
-{
-    Ok(NewNodeRef {
-        ptr: node_ptr::new_leaf(prefix, value, allocator)?,
-        allocator,
-        extra_nodes: Vec::new(),
-    })
-}
--- a/libs/neonart/src/allocator.rs
+++ b/libs/neonart/src/allocator.rs
@@ -1,158 +0,0 @@
-pub mod block;
-mod multislab;
-mod slab;
-pub mod r#static;
-
-use std::alloc::Layout;
-use std::marker::PhantomData;
-use std::mem::MaybeUninit;
-use std::sync::atomic::Ordering;
-
-use crate::allocator::multislab::MultiSlabAllocator;
-use crate::allocator::r#static::alloc_from_slice;
-
-use spin;
-
-use crate::Tree;
-pub use crate::algorithm::node_ptr::{
-    NodeInternal4, NodeInternal16, NodeInternal48, NodeInternal256, NodeLeaf,
-};
-
-#[derive(Debug)]
-pub struct OutOfMemoryError();
-
-pub trait ArtAllocator<V: crate::Value> {
-    fn alloc_tree(&self) -> *mut Tree<V>;
-
-    fn alloc_node_internal4(&self) -> *mut NodeInternal4<V>;
-    fn alloc_node_internal16(&self) -> *mut NodeInternal16<V>;
-    fn alloc_node_internal48(&self) -> *mut NodeInternal48<V>;
-    fn alloc_node_internal256(&self) -> *mut NodeInternal256<V>;
-    fn alloc_node_leaf(&self) -> *mut NodeLeaf<V>;
-
-    fn dealloc_node_internal4(&self, ptr: *mut NodeInternal4<V>);
-    fn dealloc_node_internal16(&self, ptr: *mut NodeInternal16<V>);
-    fn dealloc_node_internal48(&self, ptr: *mut NodeInternal48<V>);
-    fn dealloc_node_internal256(&self, ptr: *mut NodeInternal256<V>);
-    fn dealloc_node_leaf(&self, ptr: *mut NodeLeaf<V>);
-}
-
-pub struct ArtMultiSlabAllocator<'t, V>
-where
-    V: crate::Value,
-{
-    tree_area: spin::Mutex<Option<&'t mut MaybeUninit<Tree<V>>>>,
-
-    pub(crate) inner: MultiSlabAllocator<'t, 5>,
-
-    phantom_val: PhantomData<V>,
-}
-
-impl<'t, V: crate::Value> ArtMultiSlabAllocator<'t, V> {
-    const LAYOUTS: [Layout; 5] = [
-        Layout::new::<NodeInternal4<V>>(),
-        Layout::new::<NodeInternal16<V>>(),
-        Layout::new::<NodeInternal48<V>>(),
-        Layout::new::<NodeInternal256<V>>(),
-        Layout::new::<NodeLeaf<V>>(),
-    ];
-
-    pub fn new(area: &'t mut [MaybeUninit<u8>]) -> &'t mut ArtMultiSlabAllocator<'t, V> {
-        let (allocator_area, remain) = alloc_from_slice::<ArtMultiSlabAllocator<V>>(area);
-        let (tree_area, remain) = alloc_from_slice::<Tree<V>>(remain);
-
-        let allocator = allocator_area.write(ArtMultiSlabAllocator {
-            tree_area: spin::Mutex::new(Some(tree_area)),
-            inner: MultiSlabAllocator::new(remain, &Self::LAYOUTS),
-            phantom_val: PhantomData,
-        });
-
-        allocator
-    }
-}
-
-impl<'t, V: crate::Value> ArtAllocator<V> for ArtMultiSlabAllocator<'t, V> {
-    fn alloc_tree(&self) -> *mut Tree<V> {
-        let mut t = self.tree_area.lock();
-        if let Some(tree_area) = t.take() {
-            return tree_area.as_mut_ptr().cast();
-        }
-        panic!("cannot allocate more than one tree");
-    }
-
-    fn alloc_node_internal4(&self) -> *mut NodeInternal4<V> {
-        self.inner.alloc_slab(0).cast()
-    }
-    fn alloc_node_internal16(&self) -> *mut NodeInternal16<V> {
-        self.inner.alloc_slab(1).cast()
-    }
-    fn alloc_node_internal48(&self) -> *mut NodeInternal48<V> {
-        self.inner.alloc_slab(2).cast()
-    }
-    fn alloc_node_internal256(&self) -> *mut NodeInternal256<V> {
-        self.inner.alloc_slab(3).cast()
-    }
-    fn alloc_node_leaf(&self) -> *mut NodeLeaf<V> {
-        self.inner.alloc_slab(4).cast()
-    }
-
-    fn dealloc_node_internal4(&self, ptr: *mut NodeInternal4<V>) {
-        self.inner.dealloc_slab(0, ptr.cast())
-    }
-
-    fn dealloc_node_internal16(&self, ptr: *mut NodeInternal16<V>) {
-        self.inner.dealloc_slab(1, ptr.cast())
-    }
-    fn dealloc_node_internal48(&self, ptr: *mut NodeInternal48<V>) {
-        self.inner.dealloc_slab(2, ptr.cast())
-    }
-    fn dealloc_node_internal256(&self, ptr: *mut NodeInternal256<V>) {
-        self.inner.dealloc_slab(3, ptr.cast())
-    }
-    fn dealloc_node_leaf(&self, ptr: *mut NodeLeaf<V>) {
-        self.inner.dealloc_slab(4, ptr.cast())
-    }
-}
-
-impl<'t, V: crate::Value> ArtMultiSlabAllocator<'t, V> {
-    pub(crate) fn get_statistics(&self) -> ArtMultiSlabStats {
-        ArtMultiSlabStats {
-            num_internal4: self.inner.slab_descs[0]
-                .num_allocated
-                .load(Ordering::Relaxed),
-            num_internal16: self.inner.slab_descs[1]
-                .num_allocated
-                .load(Ordering::Relaxed),
-            num_internal48: self.inner.slab_descs[2]
-                .num_allocated
-                .load(Ordering::Relaxed),
-            num_internal256: self.inner.slab_descs[3]
-                .num_allocated
-                .load(Ordering::Relaxed),
-            num_leaf: self.inner.slab_descs[4]
-                .num_allocated
-                .load(Ordering::Relaxed),
-
-            num_blocks_internal4: self.inner.slab_descs[0].num_blocks.load(Ordering::Relaxed),
-            num_blocks_internal16: self.inner.slab_descs[1].num_blocks.load(Ordering::Relaxed),
-            num_blocks_internal48: self.inner.slab_descs[2].num_blocks.load(Ordering::Relaxed),
-            num_blocks_internal256: self.inner.slab_descs[3].num_blocks.load(Ordering::Relaxed),
-            num_blocks_leaf: self.inner.slab_descs[4].num_blocks.load(Ordering::Relaxed),
-        }
-    }
-}
-
-#[derive(Clone, Debug)]
-pub struct ArtMultiSlabStats {
-    pub num_internal4: u64,
-    pub num_internal16: u64,
-    pub num_internal48: u64,
-    pub num_internal256: u64,
-    pub num_leaf: u64,
-
-    pub num_blocks_internal4: u64,
-    pub num_blocks_internal16: u64,
-    pub num_blocks_internal48: u64,
-    pub num_blocks_internal256: u64,
-    pub num_blocks_leaf: u64,
-}
--- a/libs/neonart/src/allocator/block.rs
+++ b/libs/neonart/src/allocator/block.rs
@@ -1,191 +0,0 @@
-//! Simple allocator of fixed-size blocks
-
-use std::mem::MaybeUninit;
-use std::sync::atomic::{AtomicU64, Ordering};
-
-use spin;
-
-pub const BLOCK_SIZE: usize = 16 * 1024;
-
-const INVALID_BLOCK: u64 = u64::MAX;
-
-pub(crate) struct BlockAllocator<'t> {
-    blocks_ptr: &'t [MaybeUninit<u8>],
-    num_blocks: u64,
-    num_initialized: AtomicU64,
-
-    freelist_head: spin::Mutex<u64>,
-}
-
-struct FreeListBlock {
-    inner: spin::Mutex<FreeListBlockInner>,
-}
-
-struct FreeListBlockInner {
-    next: u64,
-
-    num_free_blocks: u64,
-    free_blocks: [u64; 100], // FIXME: fill the rest of the block
-}
-
-impl<'t> BlockAllocator<'t> {
-    pub(crate) fn new(area: &'t mut [MaybeUninit<u8>]) -> Self {
-        // Use all the space for the blocks
-        let padding = area.as_ptr().align_offset(BLOCK_SIZE);
-        let remain = &mut area[padding..];
-
-        let num_blocks = (remain.len() / BLOCK_SIZE) as u64;
-
-        BlockAllocator {
-            blocks_ptr: remain,
-            num_blocks,
-            num_initialized: AtomicU64::new(0),
-            freelist_head: spin::Mutex::new(INVALID_BLOCK),
-        }
-    }
-
-    /// safety: you must hold a lock on the pointer to this block, otherwise it might get
-    /// reused for another kind of block
-    fn read_freelist_block(&self, blkno: u64) -> &FreeListBlock {
-        let ptr: *const FreeListBlock = self.get_block_ptr(blkno).cast();
-        unsafe { ptr.as_ref().unwrap() }
-    }
-
-    fn get_block_ptr(&self, blkno: u64) -> *mut u8 {
-        assert!(blkno < self.num_blocks);
-        unsafe {
-            self.blocks_ptr
-                .as_ptr()
-                .byte_offset(blkno as isize * BLOCK_SIZE as isize)
-        }
-        .cast_mut()
-        .cast()
-    }
-
-    #[allow(clippy::mut_from_ref)]
-    pub(crate) fn alloc_block(&self) -> &mut [MaybeUninit<u8>] {
-        // FIXME: handle OOM
-        let blkno = self.alloc_block_internal();
-        if blkno == INVALID_BLOCK {
-            panic!("out of memory");
-        }
-
-        let ptr: *mut MaybeUninit<u8> = self.get_block_ptr(blkno).cast();
-        unsafe { std::slice::from_raw_parts_mut(ptr, BLOCK_SIZE) }
-    }
-
-    fn alloc_block_internal(&self) -> u64 {
-        //  check the free list.
-        {
-            let mut freelist_head = self.freelist_head.lock();
-            if *freelist_head != INVALID_BLOCK {
-                let freelist_block = self.read_freelist_block(*freelist_head);
-
-                // acquire lock on the freelist block before releasing the lock on the parent (i.e. lock coupling)
-                let mut g = freelist_block.inner.lock();
-
-                if g.num_free_blocks > 0 {
-                    g.num_free_blocks -= 1;
-                    let result = g.free_blocks[g.num_free_blocks as usize];
-                    return result;
-                } else {
-                    // consume the freelist block itself
-                    let result = *freelist_head;
-                    *freelist_head = g.next;
-                    // This freelist block is now unlinked and can be repurposed
-                    drop(g);
-                    return result;
-                }
-            }
-        }
-
-        // If there are some blocks left that we've never used, pick next such block
-        let mut next_uninitialized = self.num_initialized.load(Ordering::Relaxed);
-        while next_uninitialized < self.num_blocks {
-            match self.num_initialized.compare_exchange(
-                next_uninitialized,
-                next_uninitialized + 1,
-                Ordering::Relaxed,
-                Ordering::Relaxed,
-            ) {
-                Ok(_) => {
-                    return next_uninitialized;
-                }
-                Err(old) => {
-                    next_uninitialized = old;
-                    continue;
-                }
-            }
-        }
-
-        // out of blocks
-        return INVALID_BLOCK;
-    }
-
-    // TODO: this is currently unused. The slab allocator never releases blocks
-    #[allow(dead_code)]
-    pub(crate) fn release_block(&self, block_ptr: *mut u8) {
-        let blockno = unsafe { block_ptr.byte_offset_from(self.blocks_ptr) / BLOCK_SIZE as isize };
-        self.release_block_internal(blockno as u64);
-    }
-
-    fn release_block_internal(&self, blockno: u64) {
-        let mut freelist_head = self.freelist_head.lock();
-        if *freelist_head != INVALID_BLOCK {
-            let freelist_block = self.read_freelist_block(*freelist_head);
-
-            // acquire lock on the freelist block before releasing the lock on the parent (i.e. lock coupling)
-            let mut g = freelist_block.inner.lock();
-
-            let num_free_blocks = g.num_free_blocks;
-            if num_free_blocks < g.free_blocks.len() as u64 {
-                g.free_blocks[num_free_blocks as usize] = blockno;
-                g.num_free_blocks += 1;
-                return;
-            }
-        }
-
-        // Convert the block into a new freelist block
-        let block_ptr: *mut FreeListBlock = self.get_block_ptr(blockno).cast();
-        let init = FreeListBlock {
-            inner: spin::Mutex::new(FreeListBlockInner {
-                next: *freelist_head,
-                num_free_blocks: 0,
-                free_blocks: [INVALID_BLOCK; 100],
-            }),
-        };
-        unsafe { (*block_ptr) = init };
-        *freelist_head = blockno;
-    }
-
-    // for debugging
-    pub(crate) fn get_statistics(&self) -> BlockAllocatorStats {
-        let mut num_free_blocks = 0;
-
-        let mut _prev_lock = None;
-        let head_lock = self.freelist_head.lock();
-        let mut next_blk = *head_lock;
-        let mut _head_lock = Some(head_lock);
-        while next_blk != INVALID_BLOCK {
-            let freelist_block = self.read_freelist_block(next_blk);
-            let lock = freelist_block.inner.lock();
-            num_free_blocks += lock.num_free_blocks;
-            next_blk = lock.next;
-            _prev_lock = Some(lock); // hold the lock until we've read the next block
-            _head_lock = None;
-        }
-
-        BlockAllocatorStats {
-            num_blocks: self.num_blocks,
-            num_initialized: self.num_initialized.load(Ordering::Relaxed),
-            num_free_blocks,
-        }
-    }
-}
-
-#[derive(Clone, Debug)]
-pub struct BlockAllocatorStats {
-    pub num_blocks: u64,
-    pub num_initialized: u64,
-    pub num_free_blocks: u64,
-}
--- a/libs/neonart/src/allocator/multislab.rs
+++ b/libs/neonart/src/allocator/multislab.rs
@@ -1,33 +0,0 @@
-use std::alloc::Layout;
-use std::mem::MaybeUninit;
-
-use crate::allocator::block::BlockAllocator;
-use crate::allocator::slab::SlabDesc;
-
-pub struct MultiSlabAllocator<'t, const N: usize> {
-    pub(crate) block_allocator: BlockAllocator<'t>,
-
-    pub(crate) slab_descs: [SlabDesc; N],
-}
-
-impl<'t, const N: usize> MultiSlabAllocator<'t, N> {
-    pub(crate) fn new(
-        area: &'t mut [MaybeUninit<u8>],
-        layouts: &[Layout; N],
-    ) -> MultiSlabAllocator<'t, N> {
-        let block_allocator = BlockAllocator::new(area);
-        MultiSlabAllocator {
-            block_allocator,
-
-            slab_descs: std::array::from_fn(|i| SlabDesc::new(&layouts[i])),
-        }
-    }
-
-    pub(crate) fn alloc_slab(&self, slab_idx: usize) -> *mut u8 {
-        self.slab_descs[slab_idx].alloc_chunk(&self.block_allocator)
-    }
-
-    pub(crate) fn dealloc_slab(&self, slab_idx: usize, ptr: *mut u8) {
-        self.slab_descs[slab_idx].dealloc_chunk(ptr, &self.block_allocator)
-    }
-}
--- a/libs/neonart/src/allocator/slab.rs
+++ b/libs/neonart/src/allocator/slab.rs
@@ -1,432 +0,0 @@
-//! A slab allocator that carves out fixed-size chunks from larger blocks.
-//!
-//!
-
-use std::alloc::Layout;
-use std::mem::MaybeUninit;
-use std::ops::Deref;
-use std::sync::atomic::{AtomicU32, AtomicU64, Ordering};
-
-use spin;
-
-use super::alloc_from_slice;
-use super::block::BlockAllocator;
-
-use crate::allocator::block::BLOCK_SIZE;
-
-pub(crate) struct SlabDesc {
-    pub(crate) layout: Layout,
-
-    block_lists: spin::RwLock<BlockLists>,
-
-    pub(crate) num_blocks: AtomicU64,
-    pub(crate) num_allocated: AtomicU64,
-}
-
-// FIXME: Not sure if SlabDesc is really Sync or Send. It probably is when it's empty, but
-// 'block_lists' contains pointers when it's not empty. In the current use as part of the
-// the art tree, SlabDescs are only moved during initialization.
-unsafe impl Sync for SlabDesc {}
-unsafe impl Send for SlabDesc {}
-
-#[derive(Default, Debug)]
-struct BlockLists {
-    full_blocks: BlockList,
-    nonfull_blocks: BlockList,
-}
-
-impl BlockLists {
-    // Unlink a node. It must be in either one of the two lists.
-    unsafe fn unlink(&mut self, elem: *mut SlabBlockHeader) {
-        let list = unsafe {
-            if (*elem).next.is_null() {
-                if self.full_blocks.tail == elem {
-                    Some(&mut self.full_blocks)
-                } else {
-                    Some(&mut self.nonfull_blocks)
-                }
-            } else if (*elem).prev.is_null() {
-                if self.full_blocks.head == elem {
-                    Some(&mut self.full_blocks)
-                } else {
-                    Some(&mut self.nonfull_blocks)
-                }
-            } else {
-                None
-            }
-        };
-        unsafe { unlink_slab_block(list, elem) };
-    }
-}
-
-unsafe fn unlink_slab_block(mut list: Option<&mut BlockList>, elem: *mut SlabBlockHeader) {
-    unsafe {
-        if (*elem).next.is_null() {
-            assert_eq!(list.as_ref().unwrap().tail, elem);
-            list.as_mut().unwrap().tail = (*elem).prev;
-        } else {
-            assert_eq!((*(*elem).next).prev, elem);
-            (*(*elem).next).prev = (*elem).prev;
-        }
-        if (*elem).prev.is_null() {
-            assert_eq!(list.as_ref().unwrap().head, elem);
-            list.as_mut().unwrap().head = (*elem).next;
-        } else {
-            assert_eq!((*(*elem).prev).next, elem);
-            (*(*elem).prev).next = (*elem).next;
-        }
-    }
-}
-
-#[derive(Debug)]
-struct BlockList {
-    head: *mut SlabBlockHeader,
-    tail: *mut SlabBlockHeader,
-}
-
-impl Default for BlockList {
-    fn default() -> Self {
-        BlockList {
-            head: std::ptr::null_mut(),
-            tail: std::ptr::null_mut(),
-        }
-    }
-}
-
-impl BlockList {
-    unsafe fn push_head(&mut self, elem: *mut SlabBlockHeader) {
-        unsafe {
-            if self.is_empty() {
-                self.tail = elem;
-                (*elem).next = std::ptr::null_mut();
-            } else {
-                (*elem).next = self.head;
-                (*self.head).prev = elem;
-            }
-            (*elem).prev = std::ptr::null_mut();
-            self.head = elem;
-        }
-    }
-
-    fn is_empty(&self) -> bool {
-        self.head.is_null()
-    }
-
-    unsafe fn unlink(&mut self, elem: *mut SlabBlockHeader) {
-        unsafe { unlink_slab_block(Some(self), elem) }
-    }
-
-    #[cfg(test)]
-    fn dump(&self) {
-        let mut next = self.head;
-
-        while !next.is_null() {
-            let n = unsafe { next.as_ref() }.unwrap();
-            eprintln!(
-                "  blk {:?} (free {}/{})",
-                next,
-                n.num_free_chunks.load(Ordering::Relaxed),
-                n.num_chunks
-            );
-            next = n.next;
-        }
-    }
-}
-
-impl SlabDesc {
-    pub(crate) fn new(layout: &Layout) -> SlabDesc {
-        SlabDesc {
-            layout: *layout,
-            block_lists: spin::RwLock::new(BlockLists::default()),
-            num_allocated: AtomicU64::new(0),
-            num_blocks: AtomicU64::new(0),
-        }
-    }
-}
-
-#[derive(Debug)]
-struct SlabBlockHeader {
-    free_chunks_head: spin::Mutex<*mut FreeChunk>,
-    num_free_chunks: AtomicU32,
-    num_chunks: u32, // this is really a constant for a given Layout
-
-    // these fields are protected by the lock on the BlockLists
-    prev: *mut SlabBlockHeader,
-    next: *mut SlabBlockHeader,
-}
-
-struct FreeChunk {
-    next: *mut FreeChunk,
-}
-
-enum ReadOrWriteGuard<'a, T> {
-    Read(spin::RwLockReadGuard<'a, T>),
-    Write(spin::RwLockWriteGuard<'a, T>),
-}
-
-impl<'a, T> Deref for ReadOrWriteGuard<'a, T> {
-    type Target = T;
-
-    fn deref(&self) -> &<Self as Deref>::Target {
-        match self {
-            ReadOrWriteGuard::Read(g) => g.deref(),
-            ReadOrWriteGuard::Write(g) => g.deref(),
-        }
-    }
-}
-
-impl SlabDesc {
-    pub fn alloc_chunk(&self, block_allocator: &BlockAllocator) -> *mut u8 {
-        // Are there any free chunks?
-        let mut acquire_write = false;
-        'outer: loop {
-            let mut block_lists_guard = if acquire_write {
-                ReadOrWriteGuard::Write(self.block_lists.write())
-            } else {
-                ReadOrWriteGuard::Read(self.block_lists.read())
-            };
-            'inner: loop {
-                let block_ptr = block_lists_guard.nonfull_blocks.head;
-                if block_ptr.is_null() {
-                    break 'outer;
-                }
-                unsafe {
-                    let mut free_chunks_head = (*block_ptr).free_chunks_head.lock();
-                    if !(*free_chunks_head).is_null() {
-                        let result = *free_chunks_head;
-                        (*free_chunks_head) = (*result).next;
-                        let _old = (*block_ptr).num_free_chunks.fetch_sub(1, Ordering::Relaxed);
-
-                        self.num_allocated.fetch_add(1, Ordering::Relaxed);
-                        return result.cast();
-                    }
-                }
-
-                // The block at the head of the list was full. Grab write lock and retry
-                match block_lists_guard {
-                    ReadOrWriteGuard::Read(_) => {
-                        acquire_write = true;
-                        continue 'outer;
-                    }
-                    ReadOrWriteGuard::Write(ref mut g) => {
-                        // move the node to the list of full blocks
-                        unsafe {
-                            g.nonfull_blocks.unlink(block_ptr);
-                            g.full_blocks.push_head(block_ptr);
-                        };
-                        continue 'inner;
-                    }
-                }
-            }
-        }
-
-        // no free chunks. Allocate a new block (and the chunk from that)
-        let (new_block, new_chunk) = self.alloc_block_and_chunk(block_allocator);
-        self.num_blocks.fetch_add(1, Ordering::Relaxed);
-
-        // Add the block to the list in the SlabDesc
-        unsafe {
-            let mut block_lists_guard = self.block_lists.write();
-            block_lists_guard.nonfull_blocks.push_head(new_block);
-        }
-        self.num_allocated.fetch_add(1, Ordering::Relaxed);
-        new_chunk
-    }
-
-    pub fn dealloc_chunk(&self, chunk_ptr: *mut u8, _block_allocator: &BlockAllocator) {
-        // Find the block it belongs to. You can find the block from the address. (And knowing the
-        // layout, you could calculate the chunk number too.)
-        let block_ptr: *mut SlabBlockHeader = {
-            let block_addr = (chunk_ptr.addr() / BLOCK_SIZE) * BLOCK_SIZE;
-            chunk_ptr.with_addr(block_addr).cast()
-        };
-        let chunk_ptr: *mut FreeChunk = chunk_ptr.cast();
-
-        // Mark the chunk as free in 'freechunks' list
-        let num_chunks;
-        let num_free_chunks;
-        unsafe {
-            let mut free_chunks_head = (*block_ptr).free_chunks_head.lock();
-            (*chunk_ptr).next = *free_chunks_head;
-            *free_chunks_head = chunk_ptr;
-
-            num_free_chunks = (*block_ptr).num_free_chunks.fetch_add(1, Ordering::Relaxed) + 1;
-            num_chunks = (*block_ptr).num_chunks;
-        }
-
-        if num_free_chunks == 1 {
-            // If the block was full previously, add it to the nonfull blocks list. Note that
-            // we're not holding the lock anymore, so it can immediately become full again.
-            // That's harmless, it will be moved back to the full list again when a call
-            // to alloc_chunk() sees it.
-            let mut block_lists = self.block_lists.write();
-            unsafe {
-                block_lists.unlink(block_ptr);
-                block_lists.nonfull_blocks.push_head(block_ptr);
-            };
-        } else if num_free_chunks == num_chunks {
-            // If the block became completely empty, move it to the free list
-            // TODO
-            // FIXME: we're still holding the spinlock. It's not exactly safe to return it to
-            // the free blocks list, is it? Defer it as garbage to wait out concurrent updates?
-            //block_allocator.release_block()
-        }
-
-        // update stats
-        self.num_allocated.fetch_sub(1, Ordering::Relaxed);
-    }
-
-    fn alloc_block_and_chunk(
-        &self,
-        block_allocator: &BlockAllocator,
-    ) -> (*mut SlabBlockHeader, *mut u8) {
-        // fixme: handle OOM
-        let block_slice: &mut [MaybeUninit<u8>] = block_allocator.alloc_block();
-        let (block_header, remain) = alloc_from_slice::<SlabBlockHeader>(block_slice);
-
-        let padding = remain.as_ptr().align_offset(self.layout.align());
-
-        let num_chunks = (remain.len() - padding) / self.layout.size();
-
-        let first_chunk_ptr: *mut FreeChunk = remain[padding..].as_mut_ptr().cast();
-
-        unsafe {
-            let mut chunk_ptr = first_chunk_ptr;
-            for _ in 0..num_chunks - 1 {
-                let next_chunk_ptr = chunk_ptr.byte_add(self.layout.size());
-                (*chunk_ptr).next = next_chunk_ptr;
-                chunk_ptr = next_chunk_ptr;
-            }
-            (*chunk_ptr).next = std::ptr::null_mut();
-
-            let result_chunk = first_chunk_ptr;
-
-            let block_header = block_header.write(SlabBlockHeader {
-                free_chunks_head: spin::Mutex::new((*first_chunk_ptr).next),
-                prev: std::ptr::null_mut(),
-                next: std::ptr::null_mut(),
-                num_chunks: num_chunks as u32,
-                num_free_chunks: AtomicU32::new(num_chunks as u32 - 1),
-            });
-
-            (block_header, result_chunk.cast())
-        }
-    }
-
-    #[cfg(test)]
-    fn dump(&self) {
-        eprintln!(
-            "slab dump ({} blocks, {} allocated chunks)",
-            self.num_blocks.load(Ordering::Relaxed),
-            self.num_allocated.load(Ordering::Relaxed)
-        );
-        let lists = self.block_lists.read();
-
-        eprintln!("nonfull blocks:");
-        lists.nonfull_blocks.dump();
-        eprintln!("full blocks:");
-        lists.full_blocks.dump();
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    use rand::Rng;
-    use rand_distr::Zipf;
-
-    struct TestObject {
-        val: usize,
-        _dummy: [u8; BLOCK_SIZE / 4],
-    }
-
-    struct TestObjectSlab<'a>(SlabDesc, BlockAllocator<'a>);
-    impl<'a> TestObjectSlab<'a> {
-        fn new(block_allocator: BlockAllocator) -> TestObjectSlab {
-            TestObjectSlab(SlabDesc::new(&Layout::new::<TestObject>()), block_allocator)
-        }
-
-        fn alloc(&self, val: usize) -> *mut TestObject {
-            let obj: *mut TestObject = self.0.alloc_chunk(&self.1).cast();
-            unsafe { (*obj).val = val };
-            obj
-        }
-
-        fn dealloc(&self, obj: *mut TestObject) {
-            self.0.dealloc_chunk(obj.cast(), &self.1)
-        }
-    }
-
-    #[test]
-    fn test_slab_alloc() {
-        const MEM_SIZE: usize = 100000000;
-        let mut area = Box::new_uninit_slice(MEM_SIZE);
-        let block_allocator = BlockAllocator::new(&mut area);
-
-        let slab = TestObjectSlab::new(block_allocator);
-
-        let mut all: Vec<*mut TestObject> = Vec::new();
-        for i in 0..11 {
-            all.push(slab.alloc(i));
-        }
-        for i in 0..11 {
-            assert!(unsafe { (*all[i]).val == i });
-        }
-
-        let distribution = Zipf::new(10 as f64, 1.1).unwrap();
-        let mut rng = rand::rng();
-        for _ in 0..100000 {
-            slab.0.dump();
-            let idx = (rng.sample(distribution) as usize).into();
-            let ptr: *mut TestObject = all[idx];
-            if !ptr.is_null() {
-                assert_eq!(unsafe { (*ptr).val }, idx);
-                slab.dealloc(ptr);
-                all[idx] = std::ptr::null_mut();
-            } else {
-                all[idx] = slab.alloc(idx);
-            }
-        }
-    }
-
-    fn new_test_blk(i: u32) -> *mut SlabBlockHeader {
-        Box::into_raw(Box::new(SlabBlockHeader {
-            free_chunks_head: spin::Mutex::new(std::ptr::null_mut()),
-            num_free_chunks: AtomicU32::new(0),
-            num_chunks: i,
-            prev: std::ptr::null_mut(),
-            next: std::ptr::null_mut(),
-        }))
-    }
-
-    #[test]
-    fn test_block_linked_list() {
-        // note: these are leaked, but that's OK for tests
-        let a = new_test_blk(0);
-        let b = new_test_blk(1);
-
-        let mut list = BlockList::default();
-        assert!(list.is_empty());
-
-        unsafe {
-            list.push_head(a);
-            assert!(!list.is_empty());
-            list.unlink(a);
-        }
-        assert!(list.is_empty());
-
-        unsafe {
-            list.push_head(b);
-            list.push_head(a);
-            assert_eq!(list.head, a);
-            assert_eq!((*a).next, b);
-            assert_eq!((*b).prev, a);
-            assert_eq!(list.tail, b);
-
-            list.unlink(a);
-            list.unlink(b);
-            assert!(list.is_empty());
-        }
-    }
-}
--- a/libs/neonart/src/allocator/static.rs
+++ b/libs/neonart/src/allocator/static.rs
@@ -1,44 +0,0 @@
-use std::mem::MaybeUninit;
-
-pub fn alloc_from_slice<T>(
-    area: &mut [MaybeUninit<u8>],
-) -> (&mut MaybeUninit<T>, &mut [MaybeUninit<u8>]) {
-    let layout = std::alloc::Layout::new::<T>();
-
-    let area_start = area.as_mut_ptr();
-
-    // pad to satisfy alignment requirements
-    let padding = area_start.align_offset(layout.align());
-    if padding + layout.size() > area.len() {
-        panic!("out of memory");
-    }
-    let area = &mut area[padding..];
-    let (result_area, remain) = area.split_at_mut(layout.size());
-
-    let result_ptr: *mut MaybeUninit<T> = result_area.as_mut_ptr().cast();
-    let result = unsafe { result_ptr.as_mut().unwrap() };
-
-    (result, remain)
-}
-
-pub fn alloc_array_from_slice<T>(
-    area: &mut [MaybeUninit<u8>],
-    len: usize,
-) -> (&mut [MaybeUninit<T>], &mut [MaybeUninit<u8>]) {
-    let layout = std::alloc::Layout::new::<T>();
-
-    let area_start = area.as_mut_ptr();
-
-    // pad to satisfy alignment requirements
-    let padding = area_start.align_offset(layout.align());
-    if padding + layout.size() * len > area.len() {
-        panic!("out of memory");
-    }
-    let area = &mut area[padding..];
-    let (result_area, remain) = area.split_at_mut(layout.size() * len);
-
-    let result_ptr: *mut MaybeUninit<T> = result_area.as_mut_ptr().cast();
-    let result = unsafe { std::slice::from_raw_parts_mut(result_ptr.as_mut().unwrap(), len) };
-
-    (result, remain)
-}
--- a/libs/neonart/src/epoch.rs
+++ b/libs/neonart/src/epoch.rs
@@ -1,147 +0,0 @@
-//! This is similar to crossbeam_epoch crate, but works in shared memory
-
-use std::sync::atomic::{AtomicU64, AtomicUsize, Ordering};
-
-use crossbeam_utils::CachePadded;
-use spin;
-
-const NUM_SLOTS: usize = 1000;
-
-/// This is the struct that is stored in shmem
-///
-/// bit 0: is it pinned or not?
-/// rest of the bits are the epoch counter.
-pub struct EpochShared {
-    global_epoch: AtomicU64,
-    participants: [CachePadded<AtomicU64>; NUM_SLOTS],
-
-    broadcast_lock: spin::Mutex<()>,
-}
-
-impl EpochShared {
-    pub fn new() -> EpochShared {
-        EpochShared {
-            global_epoch: AtomicU64::new(2),
-            participants: [const { CachePadded::new(AtomicU64::new(2)) }; NUM_SLOTS],
-            broadcast_lock: spin::Mutex::new(()),
-        }
-    }
-
-    pub fn register(&self) -> LocalHandle {
-        LocalHandle {
-            global: self,
-            last_slot: AtomicUsize::new(0), // todo: choose more intelligently
-        }
-    }
-
-    fn release_pin(&self, slot: usize, _epoch: u64) {
-        let global_epoch = self.global_epoch.load(Ordering::Relaxed);
-        self.participants[slot].store(global_epoch, Ordering::Relaxed);
-    }
-
-    fn pin_internal(&self, slot_hint: usize) -> (usize, u64) {
-        // pick a slot
-        let mut slot = slot_hint;
-        let epoch = loop {
-            let old = self.participants[slot].fetch_or(1, Ordering::Relaxed);
-            if old & 1 == 0 {
-                // Got this slot
-                break old;
-            }
-
-            // the slot was busy by another thread / process. try a different slot
-            slot += 1;
-            if slot == NUM_SLOTS {
-                slot = 0;
-            }
-            continue;
-        };
-        (slot, epoch)
-    }
-
-    pub(crate) fn advance(&self) -> u64 {
-        // Advance the global epoch
-        let old_epoch = self.global_epoch.fetch_add(2, Ordering::Relaxed);
-        let new_epoch = old_epoch + 2;
-
-        // Anyone that release their pin after this will update their slot.
-        new_epoch
-    }
-
-    pub(crate) fn broadcast(&self) {
-        let Some(_guard) = self.broadcast_lock.try_lock() else {
-            return;
-        };
-
-        let epoch = self.global_epoch.load(Ordering::Relaxed);
-        let old_epoch = epoch.wrapping_sub(2);
-
-        // Update all free slots.
-        for i in 0..NUM_SLOTS {
-            // TODO: check result, as a sanity check. It should either be the old epoch, or pinned
-            let _ = self.participants[i].compare_exchange(
-                old_epoch,
-                epoch,
-                Ordering::Relaxed,
-                Ordering::Relaxed,
-            );
-        }
-
-        // FIXME: memory fence here, since we used Relaxed?
-    }
-
-    pub(crate) fn get_oldest(&self) -> u64 {
-        // Read all slots.
-        let now = self.global_epoch.load(Ordering::Relaxed);
-        let mut oldest = now;
-        for i in 0..NUM_SLOTS {
-            let this_epoch = self.participants[i].load(Ordering::Relaxed);
-            let delta = now.wrapping_sub(this_epoch);
-            if delta > u64::MAX / 2 {
-                // this is very recent
-            } else {
-                if delta > now.wrapping_sub(oldest) {
-                    oldest = this_epoch;
-                }
-            }
-        }
-        oldest
-    }
-
-    pub(crate) fn get_current(&self) -> u64 {
-        self.global_epoch.load(Ordering::Relaxed)
-    }
-}
-
-pub(crate) struct EpochPin<'e> {
-    slot: usize,
-    pub(crate) epoch: u64,
-
-    handle: &'e LocalHandle<'e>,
-}
-
-impl<'e> Drop for EpochPin<'e> {
-    fn drop(&mut self) {
-        self.handle.global.release_pin(self.slot, self.epoch);
-    }
-}
-
-pub struct LocalHandle<'g> {
-    global: &'g EpochShared,
-
-    last_slot: AtomicUsize,
-}
-
-impl<'g> LocalHandle<'g> {
-    pub fn pin(&self) -> EpochPin {
-        let (slot, epoch) = self
-            .global
-            .pin_internal(self.last_slot.load(Ordering::Relaxed));
-        self.last_slot.store(slot, Ordering::Relaxed);
-        EpochPin {
-            handle: self,
-            epoch,
-            slot,
-        }
-    }
-}
--- a/libs/neonart/src/lib.rs
+++ b/libs/neonart/src/lib.rs
@@ -1,587 +0,0 @@
-//! Adaptive Radix Tree (ART) implementation, with Optimistic Lock Coupling.
-//!
-//! The data structure is described in these two papers:
-//!
-//! [1] Leis, V. & Kemper, Alfons & Neumann, Thomas. (2013).
-//!     The adaptive radix tree: ARTful indexing for main-memory databases.
-//!     Proceedings - International Conference on Data Engineering. 38-49. 10.1109/ICDE.2013.6544812.
-//!     https://db.in.tum.de/~leis/papers/ART.pdf
-//!
-//! [2] Leis, Viktor & Scheibner, Florian & Kemper, Alfons & Neumann, Thomas. (2016).
-//!     The ART of practical synchronization.
-//!     1-8. 10.1145/2933349.2933352.
-//!     https://db.in.tum.de/~leis/papers/artsync.pdf
-//!
-//! [1] describes the base data structure, and [2] describes the Optimistic Lock Coupling that we
-//! use.
-//!
-//! The papers mention a few different variants. We have made the following choices in this
-//! implementation:
-//!
-//! - All keys have the same length
-//!
-//! - Single-value leaves.
-//!
-//! - For collapsing inner nodes, we use the Pessimistic approach, where each inner node stores a
-//!   variable length "prefix", which stores the keys of all the one-way nodes which have been
-//!   removed. However, similar to the "hybrid" approach described in the paper, each node only has
-//!   space for a constant-size prefix of 8 bytes. If a node would have a longer prefix, then we
-//!   create create one-way nodes to store them. (There was no particular reason for this choice,
-//!   the "hybrid" approach described in the paper might be better.)
-//!
-//! - For concurrency, we use Optimistic Lock Coupling. The paper [2] also describes another method,
-//!   ROWEX, which generally performs better when there is contention, but that is not important
-//!   for use and Optimisic Lock Coupling is simpler to implement.
-//!
-//! ## Requirements
-//!
-//! This data structure is currently used for the integrated LFC, relsize and last-written LSN cache
-//! in the compute communicator, part of the 'neon' Postgres extension. We have some unique
-//! requirements, which is why we had to write our own. Namely:
-//!
-//! - The data structure has to live in fixed-sized shared memory segment. That rules out any
-//!   built-in Rust collections and most crates. (Except possibly with the 'allocator_api' rust
-//!   feature, which still nightly-only experimental as of this writing).
-//!
-//! - The data structure is accessed from multiple processes. Only one process updates the data
-//!   structure, but other processes perform reads. That rules out using built-in Rust locking
-//!   primitives like Mutex and RwLock, and most crates too.
-//!
-//! - Within the one process with write-access, multiple threads can perform updates concurrently.
-//!   That rules out using PostgreSQL LWLocks for the locking.
-//!
-//! The implementation is generic, and doesn't depend on any PostgreSQL specifics, but it has been
-//! written with that usage and the above constraints in mind. Some noteworthy assumptions:
-//!
-//! - Contention is assumed to be rare. In the integrated cache in PostgreSQL, there's higher level
-//!   locking in the PostgreSQL buffer manager, which ensures that two backends should not try to
-//!   read / write the same page at the same time. (Prefetching can conflict with actual reads,
-//!   however.)
-//!
-//!  - The keys in the integrated cache are 17 bytes long.
-//!
-//! ## Usage
-//!
-//! Because this is designed to be used as a Postgres shared memory data structure, initialization
-//! happens in three stages:
-//!
-//! 0. A fixed area of shared memory is allocated at postmaster startup.
-//!
-//! 1. TreeInitStruct::new() is called to initialize it, still in Postmaster process, before any
-//!    other process or thread is running. It returns a TreeInitStruct, which is inherited by all
-//!    the processes through fork().
-//!
-//! 2. One process may have write-access to the struct, by calling
-//!    [TreeInitStruct::attach_writer]. (That process is the communicator process.)
-//!
-//! 3. Other processes get read-access to the struct, by calling [TreeInitStruct::attach_reader]
-//!
-//! "Write access" means that you can insert / update / delete values in the tree.
-//!
-//! NOTE: The Values stored in the tree are sometimes moved, when a leaf node fills up and a new
-//! larger node needs to be allocated. The versioning and epoch-based allocator ensure that the data
-//! structure stays consistent, but if the Value has interior mutability, like atomic fields,
-//! updates to such fields might be lost if the leaf node is concurrently moved! If that becomes a
-//! problem, the version check could be passed up to the caller, so that the caller could detect the
-//! lost updates and retry the operation.
-//!
-//! ## Implementation
-//!
-//! node_ptr: Provides low-level implementations of the four different node types (eight actually,
-//! since there is an Internal and Leaf variant of each)
-//!
-//! lock_and_version.rs: Provides an abstraction for the combined lock and version counter on each
-//! node.
-//!
-//! node_ref.rs: The code in node_ptr.rs deals with raw pointers. node_ref.rs provides more type-safe
-//!   abstractions on top.
-//!
-//! algorithm.rs: Contains the functions to implement lookups and updates in the tree
-//!
-//! allocator.rs: Provides a facility to allocate memory for the tree nodes. (We must provide our
-//!   own abstraction for that because we need the data structure to live in a pre-allocated shared
-//!   memory segment).
-//!
-//! epoch.rs: The data structure requires that when a node is removed from the tree, it is not
-//!   immediately deallocated, but stays around for as long as concurrent readers might still have
-//!   pointers to them. This is enforced by an epoch system. This is similar to
-//!   e.g. crossbeam_epoch, but we couldn't use that either because it has to work across processes
-//!   communicating over the shared memory segment.
-//!
-//! ## See also
-//!
-//! There are some existing Rust ART implementations out there, but none of them filled all
-//! the requirements:
-//!
-//! - https://github.com/XiangpengHao/congee
-//! - https://github.com/declanvk/blart
-//!
-//! ## TODO
-//!
-//! - Removing values has not been implemented
-
-mod algorithm;
-pub mod allocator;
-mod epoch;
-
-use algorithm::RootPtr;
-use algorithm::node_ptr::NodePtr;
-
-use std::collections::VecDeque;
-use std::fmt::Debug;
-use std::marker::PhantomData;
-use std::ptr::NonNull;
-use std::sync::atomic::{AtomicBool, Ordering};
-
-use crate::epoch::EpochPin;
-
-#[cfg(test)]
-mod tests;
-
-use allocator::ArtAllocator;
-pub use allocator::ArtMultiSlabAllocator;
-pub use allocator::OutOfMemoryError;
-
-/// Fixed-length key type.
-///
-pub trait Key: Debug {
-    const KEY_LEN: usize;
-
-    fn as_bytes(&self) -> &[u8];
-}
-
-/// Values stored in the tree
-///
-/// Values need to be Cloneable, because when a node "grows", the value is copied to a new node and
-/// the old sticks around until all readers that might see the old value are gone.
-// fixme obsolete, no longer needs Clone
-pub trait Value {}
-
-const MAX_GARBAGE: usize = 1024;
-
-/// The root of the tree, plus other tree-wide data. This is stored in the shared memory.
-pub struct Tree<V: Value> {
-    /// For simplicity, so that we never need to grow or shrink the root, the root node is always an
-    /// Internal256 node. Also, it never has a prefix (that's actually a bit wasteful, incurring one
-    /// indirection to every lookup)
-    root: RootPtr<V>,
-
-    writer_attached: AtomicBool,
-
-    epoch: epoch::EpochShared,
-}
-
-unsafe impl<V: Value + Sync> Sync for Tree<V> {}
-unsafe impl<V: Value + Send> Send for Tree<V> {}
-
-struct GarbageQueue<V>(VecDeque<(NodePtr<V>, u64)>);
-
-unsafe impl<V: Value + Sync> Sync for GarbageQueue<V> {}
-unsafe impl<V: Value + Send> Send for GarbageQueue<V> {}
-
-impl<V> GarbageQueue<V> {
-    fn new() -> GarbageQueue<V> {
-        GarbageQueue(VecDeque::with_capacity(MAX_GARBAGE))
-    }
-
-    fn remember_obsolete_node(&mut self, ptr: NodePtr<V>, epoch: u64) {
-        self.0.push_front((ptr, epoch));
-    }
-
-    fn next_obsolete(&mut self, cutoff_epoch: u64) -> Option<NodePtr<V>> {
-        if let Some(back) = self.0.back() {
-            if back.1 < cutoff_epoch {
-                return Some(self.0.pop_back().unwrap().0);
-            }
-        }
-        None
-    }
-}
-
-/// Struct created at postmaster startup
-pub struct TreeInitStruct<'t, K: Key, V: Value, A: ArtAllocator<V>> {
-    tree: &'t Tree<V>,
-
-    allocator: &'t A,
-
-    phantom_key: PhantomData<K>,
-}
-
-/// The worker process has a reference to this. The write operations are only safe
-/// from the worker process
-pub struct TreeWriteAccess<'t, K: Key, V: Value, A: ArtAllocator<V>>
-where
-    K: Key,
-    V: Value,
-{
-    tree: &'t Tree<V>,
-
-    pub allocator: &'t A,
-
-    epoch_handle: epoch::LocalHandle<'t>,
-
-    phantom_key: PhantomData<K>,
-
-    /// Obsolete nodes that cannot be recycled until their epoch expires.
-    garbage: spin::Mutex<GarbageQueue<V>>,
-}
-
-/// The backends have a reference to this. It cannot be used to modify the tree
-pub struct TreeReadAccess<'t, K: Key, V: Value>
-where
-    K: Key,
-    V: Value,
-{
-    tree: &'t Tree<V>,
-
-    epoch_handle: epoch::LocalHandle<'t>,
-
-    phantom_key: PhantomData<K>,
-}
-
-impl<'a, 't: 'a, K: Key, V: Value, A: ArtAllocator<V>> TreeInitStruct<'t, K, V, A> {
-    pub fn new(allocator: &'t A) -> TreeInitStruct<'t, K, V, A> {
-        let tree_ptr = allocator.alloc_tree();
-        let tree_ptr = NonNull::new(tree_ptr).expect("out of memory");
-        let init = Tree {
-            root: algorithm::new_root(allocator).expect("out of memory"),
-            writer_attached: AtomicBool::new(false),
-            epoch: epoch::EpochShared::new(),
-        };
-        unsafe { tree_ptr.write(init) };
-
-        TreeInitStruct {
-            tree: unsafe { tree_ptr.as_ref() },
-            allocator,
-            phantom_key: PhantomData,
-        }
-    }
-
-    pub fn attach_writer(self) -> TreeWriteAccess<'t, K, V, A> {
-        let previously_attached = self.tree.writer_attached.swap(true, Ordering::Relaxed);
-        if previously_attached {
-            panic!("writer already attached");
-        }
-        TreeWriteAccess {
-            tree: self.tree,
-            allocator: self.allocator,
-            phantom_key: PhantomData,
-            epoch_handle: self.tree.epoch.register(),
-            garbage: spin::Mutex::new(GarbageQueue::new()),
-        }
-    }
-
-    pub fn attach_reader(self) -> TreeReadAccess<'t, K, V> {
-        TreeReadAccess {
-            tree: self.tree,
-            phantom_key: PhantomData,
-            epoch_handle: self.tree.epoch.register(),
-        }
-    }
-}
-
-impl<'t, K: Key, V: Value, A: ArtAllocator<V>> TreeWriteAccess<'t, K, V, A> {
-    pub fn start_write<'g>(&'t self) -> TreeWriteGuard<'g, K, V, A>
-    where
-        't: 'g,
-    {
-        TreeWriteGuard {
-            tree_writer: self,
-            epoch_pin: self.epoch_handle.pin(),
-            phantom_key: PhantomData,
-            created_garbage: false,
-        }
-    }
-
-    pub fn start_read(&'t self) -> TreeReadGuard<'t, K, V> {
-        TreeReadGuard {
-            tree: &self.tree,
-            epoch_pin: self.epoch_handle.pin(),
-            phantom_key: PhantomData,
-        }
-    }
-}
-
-impl<'t, K: Key, V: Value> TreeReadAccess<'t, K, V> {
-    pub fn start_read(&'t self) -> TreeReadGuard<'t, K, V> {
-        TreeReadGuard {
-            tree: &self.tree,
-            epoch_pin: self.epoch_handle.pin(),
-            phantom_key: PhantomData,
-        }
-    }
-}
-
-pub struct TreeReadGuard<'e, K, V>
-where
-    K: Key,
-    V: Value,
-{
-    tree: &'e Tree<V>,
-
-    epoch_pin: EpochPin<'e>,
-    phantom_key: PhantomData<K>,
-}
-
-impl<'e, K: Key, V: Value> TreeReadGuard<'e, K, V> {
-    pub fn get(&'e self, key: &K) -> Option<&'e V> {
-        algorithm::search(key, self.tree.root, &self.epoch_pin)
-    }
-}
-
-pub struct TreeWriteGuard<'e, K, V, A>
-where
-    K: Key,
-    V: Value,
-    A: ArtAllocator<V>,
-{
-    tree_writer: &'e TreeWriteAccess<'e, K, V, A>,
-
-    epoch_pin: EpochPin<'e>,
-    phantom_key: PhantomData<K>,
-
-    created_garbage: bool,
-}
-
-pub enum UpdateAction<V> {
-    Nothing,
-    Insert(V),
-    Remove,
-}
-
-impl<'e, K: Key, V: Value, A: ArtAllocator<V>> TreeWriteGuard<'e, K, V, A> {
-    /// Get a value
-    pub fn get(&'e mut self, key: &K) -> Option<&'e V> {
-        algorithm::search(key, self.tree_writer.tree.root, &self.epoch_pin)
-    }
-
-    /// Insert a value
-    pub fn insert(self, key: &K, value: V) -> Result<bool, OutOfMemoryError> {
-        let mut success = None;
-
-        self.update_with_fn(key, |existing| {
-            if let Some(_) = existing {
-                success = Some(false);
-                UpdateAction::Nothing
-            } else {
-                success = Some(true);
-                UpdateAction::Insert(value)
-            }
-        })?;
-        Ok(success.expect("value_fn not called"))
-    }
-
-    /// Remove value. Returns true if it existed
-    pub fn remove(self, key: &K) -> bool {
-        let mut result = false;
-        // FIXME: It's not clear if OOM is expected while removing. It seems
-        // not nice, but shrinking a node can OOM. Then again, we could opt
-        // to not shrink a node if we cannot allocate, to live a little longer.
-        self.update_with_fn(key, |existing| match existing {
-            Some(_) => {
-                result = true;
-                UpdateAction::Remove
-            }
-            None => UpdateAction::Nothing,
-        })
-        .expect("out of memory while removing");
-        result
-    }
-
-    /// Try to remove value and return the old value.
-    pub fn remove_and_return(self, key: &K) -> Option<V>
-    where
-        V: Clone,
-    {
-        let mut old = None;
-        self.update_with_fn(key, |existing| {
-            old = existing.cloned();
-            UpdateAction::Remove
-        })
-        .expect("out of memory while removing");
-        old
-    }
-
-    /// Update key using the given function. All the other modifying operations are based on this.
-    ///
-    /// The function is passed a reference to the existing value, if any. If the function
-    /// returns None, the value is removed from the tree (or if there was no existing value,
-    /// does nothing). If the function returns Some, the existing value is replaced, of if there
-    /// was no existing value, it is inserted. FIXME: update comment
-    pub fn update_with_fn<F>(mut self, key: &K, value_fn: F) -> Result<(), OutOfMemoryError>
-    where
-        F: FnOnce(Option<&V>) -> UpdateAction<V>,
-    {
-        algorithm::update_fn(key, value_fn, self.tree_writer.tree.root, &mut self)?;
-
-        if self.created_garbage {
-            let _ = self.collect_garbage();
-        }
-        Ok(())
-    }
-
-    fn remember_obsolete_node(&mut self, ptr: NodePtr<V>) {
-        self.tree_writer
-            .garbage
-            .lock()
-            .remember_obsolete_node(ptr, self.epoch_pin.epoch);
-        self.created_garbage = true;
-    }
-
-    // returns number of nodes recycled
-    fn collect_garbage(&self) -> usize {
-        self.tree_writer.tree.epoch.advance();
-        self.tree_writer.tree.epoch.broadcast();
-
-        let cutoff_epoch = self.tree_writer.tree.epoch.get_oldest();
-
-        let mut result = 0;
-        let mut garbage_queue = self.tree_writer.garbage.lock();
-        while let Some(ptr) = garbage_queue.next_obsolete(cutoff_epoch) {
-            ptr.deallocate(self.tree_writer.allocator);
-            result += 1;
-        }
-        result
-    }
-}
-
-pub struct TreeIterator<K>
-where
-    K: Key + for<'a> From<&'a [u8]>,
-{
-    done: bool,
-    pub next_key: Vec<u8>,
-    max_key: Option<Vec<u8>>,
-
-    phantom_key: PhantomData<K>,
-}
-
-impl<K> TreeIterator<K>
-where
-    K: Key + for<'a> From<&'a [u8]>,
-{
-    pub fn new_wrapping() -> TreeIterator<K> {
-        let mut next_key = Vec::new();
-        next_key.resize(K::KEY_LEN, 0);
-        TreeIterator {
-            done: false,
-            next_key,
-            max_key: None,
-            phantom_key: PhantomData,
-        }
-    }
-
-    pub fn new(range: &std::ops::Range<K>) -> TreeIterator<K> {
-        let result = TreeIterator {
-            done: false,
-            next_key: Vec::from(range.start.as_bytes()),
-            max_key: Some(Vec::from(range.end.as_bytes())),
-            phantom_key: PhantomData,
-        };
-        assert_eq!(result.next_key.len(), K::KEY_LEN);
-        assert_eq!(result.max_key.as_ref().unwrap().len(), K::KEY_LEN);
-
-        result
-    }
-
-    pub fn next<'g, V>(&mut self, read_guard: &'g TreeReadGuard<'g, K, V>) -> Option<(K, &'g V)>
-    where
-        V: Value,
-    {
-        if self.done {
-            return None;
-        }
-
-        let mut wrapped_around = false;
-        loop {
-            assert_eq!(self.next_key.len(), K::KEY_LEN);
-            if let Some((k, v)) = algorithm::iter_next(
-                &mut self.next_key,
-                read_guard.tree.root,
-                &read_guard.epoch_pin,
-            ) {
-                assert_eq!(k.len(), K::KEY_LEN);
-                assert_eq!(self.next_key.len(), K::KEY_LEN);
-
-                // Check if we reached the end of the range
-                if let Some(max_key) = &self.max_key {
-                    if k.as_slice() >= max_key.as_slice() {
-                        self.done = true;
-                        break None;
-                    }
-                }
-
-                // increment the key
-                self.next_key = k.clone();
-                increment_key(self.next_key.as_mut_slice());
-                let k = k.as_slice().into();
-
-                break Some((k, v));
-            } else {
-                if self.max_key.is_some() {
-                    self.done = true;
-                } else {
-                    // Start from beginning
-                    if !wrapped_around {
-                        for i in 0..K::KEY_LEN {
-                            self.next_key[i] = 0;
-                        }
-                        wrapped_around = true;
-                        continue;
-                    } else {
-                        // The tree is completely empty
-                        // FIXME: perhaps we should remember the starting point instead.
-                        // Currently this will scan some ranges twice.
-                        break None;
-                    }
-                }
-                break None;
-            }
-        }
-    }
-}
-
-fn increment_key(key: &mut [u8]) -> bool {
-    for i in (0..key.len()).rev() {
-        let (byte, overflow) = key[i].overflowing_add(1);
-        key[i] = byte;
-        if !overflow {
-            return false;
-        }
-    }
-    true
-}
-
-// Debugging functions
-impl<'e, K: Key, V: Value + Debug, A: ArtAllocator<V>> TreeWriteGuard<'e, K, V, A> {
-    pub fn dump(&mut self, dst: &mut dyn std::io::Write) {
-        algorithm::dump_tree(self.tree_writer.tree.root, &self.epoch_pin, dst)
-    }
-}
-impl<'e, K: Key, V: Value + Debug> TreeReadGuard<'e, K, V> {
-    pub fn dump(&mut self, dst: &mut dyn std::io::Write) {
-        algorithm::dump_tree(self.tree.root, &self.epoch_pin, dst)
-    }
-}
-impl<'e, K: Key, V: Value> TreeWriteAccess<'e, K, V, ArtMultiSlabAllocator<'e, V>> {
-    pub fn get_statistics(&self) -> ArtTreeStatistics {
-        self.allocator.get_statistics();
-        ArtTreeStatistics {
-            blocks: self.allocator.inner.block_allocator.get_statistics(),
-            slabs: self.allocator.get_statistics(),
-            epoch: self.tree.epoch.get_current(),
-            oldest_epoch: self.tree.epoch.get_oldest(),
-            num_garbage: self.garbage.lock().0.len() as u64,
-        }
-    }
-}
-
-#[derive(Clone, Debug)]
-pub struct ArtTreeStatistics {
-    pub blocks: allocator::block::BlockAllocatorStats,
-    pub slabs: allocator::ArtMultiSlabStats,
-
-    pub epoch: u64,
-    pub oldest_epoch: u64,
-    pub num_garbage: u64,
-}
--- a/libs/neonart/src/tests.rs
+++ b/libs/neonart/src/tests.rs
@@ -1,243 +0,0 @@
-use std::collections::BTreeMap;
-use std::collections::HashSet;
-use std::fmt::{Debug, Formatter};
-use std::sync::atomic::{AtomicUsize, Ordering};
-
-use crate::ArtAllocator;
-use crate::ArtMultiSlabAllocator;
-use crate::TreeInitStruct;
-use crate::TreeIterator;
-use crate::TreeWriteAccess;
-use crate::UpdateAction;
-
-use crate::{Key, Value};
-
-use rand::Rng;
-use rand::seq::SliceRandom;
-use rand_distr::Zipf;
-
-const TEST_KEY_LEN: usize = 16;
-
-#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord)]
-struct TestKey([u8; TEST_KEY_LEN]);
-
-impl TestKey {
-    const MIN: TestKey = TestKey([0; TEST_KEY_LEN]);
-    const MAX: TestKey = TestKey([u8::MAX; TEST_KEY_LEN]);
-}
-
-impl Key for TestKey {
-    const KEY_LEN: usize = TEST_KEY_LEN;
-    fn as_bytes(&self) -> &[u8] {
-        &self.0
-    }
-}
-
-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())
-    }
-}
-
-impl Value for usize {}
-
-fn test_inserts<K: Into<TestKey> + Copy>(keys: &[K]) {
-    const MEM_SIZE: usize = 10000000;
-    let mut area = Box::new_uninit_slice(MEM_SIZE);
-
-    let allocator = ArtMultiSlabAllocator::new(&mut area);
-
-    let init_struct = TreeInitStruct::<TestKey, usize, _>::new(allocator);
-    let tree_writer = init_struct.attach_writer();
-
-    for (idx, k) in keys.iter().enumerate() {
-        let w = tree_writer.start_write();
-        let res = w.insert(&(*k).into(), idx);
-        assert!(res.is_ok());
-    }
-
-    for (idx, k) in keys.iter().enumerate() {
-        let r = tree_writer.start_read();
-        let value = r.get(&(*k).into());
-        assert_eq!(value, Some(idx).as_ref());
-    }
-
-    eprintln!("stats: {:?}", tree_writer.get_statistics());
-}
-
-#[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.get(&key).is_some() {
-                continue;
-            }
-            used_keys.insert(key);
-            keys.push(key.into());
-            break;
-        }
-    }
-    test_inserts(&keys);
-}
-
-struct TestValue(AtomicUsize);
-
-impl TestValue {
-    fn new(val: usize) -> TestValue {
-        TestValue(AtomicUsize::new(val))
-    }
-
-    fn load(&self) -> usize {
-        self.0.load(Ordering::Relaxed)
-    }
-}
-
-impl Value for TestValue {}
-
-impl Clone for TestValue {
-    fn clone(&self) -> TestValue {
-        TestValue::new(self.load())
-    }
-}
-
-impl Debug for TestValue {
-    fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), std::fmt::Error> {
-        write!(fmt, "{:?}", self.load())
-    }
-}
-
-#[derive(Clone, Debug)]
-struct TestOp(TestKey, Option<usize>);
-
-fn apply_op<A: ArtAllocator<TestValue>>(
-    op: &TestOp,
-    tree: &TreeWriteAccess<TestKey, TestValue, A>,
-    shadow: &mut BTreeMap<TestKey, usize>,
-) {
-    eprintln!("applying op: {op:?}");
-
-    // 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)
-    };
-
-    // apply to Art tree
-    let w = tree.start_write();
-    w.update_with_fn(&op.0, |existing| {
-        assert_eq!(existing.map(TestValue::load), shadow_existing);
-
-        match (existing, op.1) {
-            (None, None) => UpdateAction::Nothing,
-            (None, Some(new_val)) => UpdateAction::Insert(TestValue::new(new_val)),
-            (Some(_old_val), None) => UpdateAction::Remove,
-            (Some(old_val), Some(new_val)) => {
-                old_val.0.store(new_val, Ordering::Relaxed);
-                UpdateAction::Nothing
-            }
-        }
-    })
-    .expect("out of memory");
-}
-
-fn test_iter<A: ArtAllocator<TestValue>>(
-    tree: &TreeWriteAccess<TestKey, TestValue, A>,
-    shadow: &BTreeMap<TestKey, usize>,
-) {
-    let mut shadow_iter = shadow.iter();
-    let mut iter = TreeIterator::new(&(TestKey::MIN..TestKey::MAX));
-
-    loop {
-        let shadow_item = shadow_iter.next().map(|(k, v)| (k.clone(), v.clone()));
-        let r = tree.start_read();
-        let item = iter.next(&r);
-
-        if shadow_item != item.map(|(k, v)| (k, v.load())) {
-            eprintln!(
-                "FAIL: iterator returned {:?}, expected {:?}",
-                item, shadow_item
-            );
-            tree.start_read().dump(&mut std::io::stderr());
-
-            eprintln!("SHADOW:");
-            let mut si = shadow.iter();
-            while let Some(si) = si.next() {
-                eprintln!("key: {:?}, val: {}", si.0, si.1);
-            }
-            panic!(
-                "FAIL: iterator returned {:?}, expected {:?}",
-                item, shadow_item
-            );
-        }
-        if item.is_none() {
-            break;
-        }
-    }
-}
-
-#[test]
-fn random_ops() {
-    const MEM_SIZE: usize = 10000000;
-    let mut area = Box::new_uninit_slice(MEM_SIZE);
-
-    let allocator = ArtMultiSlabAllocator::new(&mut area);
-
-    let init_struct = TreeInitStruct::<TestKey, TestValue, _>::new(allocator);
-    let tree_writer = init_struct.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 mut key: TestKey = (rng.sample(distribution) as u128).into();
-
-        if rng.random_bool(0.10) {
-            key = TestKey::from(u128::from(&key) | 0xffffffff);
-        }
-
-        let op = TestOp(key, if rng.random_bool(0.75) { Some(i) } else { None });
-
-        apply_op(&op, &tree_writer, &mut shadow);
-
-        if i % 1000 == 0 {
-            eprintln!("{i} ops processed");
-            eprintln!("stats: {:?}", tree_writer.get_statistics());
-            test_iter(&tree_writer, &shadow);
-        }
-    }
-}
--- a/libs/pageserver_api/Cargo.toml
+++ b/libs/pageserver_api/Cargo.toml
@@ -18,6 +18,8 @@ bytes.workspace = true
 byteorder.workspace = true
 utils.workspace = true
 postgres_ffi_types.workspace = true
+postgres_versioninfo.workspace = true
+posthog_client_lite.workspace = true
 enum-map.workspace = true
 strum.workspace = true
 strum_macros.workspace = true
@@ -28,12 +30,13 @@ humantime-serde.workspace = true
 chrono = { workspace = true, features = ["serde"] }
 itertools.workspace = true
 storage_broker.workspace = true
-camino = {workspace = true, features = ["serde1"]}
+camino = { workspace = true, features = ["serde1"] }
 remote_storage.workspace = true
 postgres_backend.workspace = true
-nix = {workspace = true, optional = true}
+nix = { workspace = true, optional = true }
 reqwest.workspace = true
 rand.workspace = true
+tracing.workspace = true
 tracing-utils.workspace = true
 once_cell.workspace = true

--- a/libs/pageserver_api/src/config.rs
+++ b/libs/pageserver_api/src/config.rs
@@ -4,6 +4,7 @@ use camino::Utf8PathBuf;
 mod tests;

 use const_format::formatcp;
+use posthog_client_lite::PostHogClientConfig;
 pub const DEFAULT_PG_LISTEN_PORT: u16 = 64000;
 pub const DEFAULT_PG_LISTEN_ADDR: &str = formatcp!("127.0.0.1:{DEFAULT_PG_LISTEN_PORT}");
 pub const DEFAULT_HTTP_LISTEN_PORT: u16 = 9898;
@@ -63,25 +64,66 @@ impl Display for NodeMetadata {
    }
 }

-/// PostHog integration config.
+/// PostHog integration config. This is used in pageserver, storcon, and neon_local.
+/// Ensure backward compatibility when adding new fields.
 #[derive(Debug, Clone, PartialEq, Eq, serde::Serialize, serde::Deserialize)]
 pub struct PostHogConfig {
    /// PostHog project ID
-    pub project_id: String,
+    #[serde(default)]
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub project_id: Option<String>,
    /// Server-side (private) API key
-    pub server_api_key: String,
+    #[serde(default)]
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub server_api_key: Option<String>,
    /// Client-side (public) API key
-    pub client_api_key: String,
+    #[serde(default)]
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub client_api_key: Option<String>,
    /// Private API URL
-    pub private_api_url: String,
+    #[serde(default)]
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub private_api_url: Option<String>,
    /// Public API URL
-    pub public_api_url: String,
-    /// Refresh interval for the feature flag spec
+    #[serde(default)]
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub public_api_url: Option<String>,
+    /// Refresh interval for the feature flag spec.
+    /// The storcon will push the feature flag spec to the pageserver. If the pageserver does not receive
+    /// the spec for `refresh_interval`, it will fetch the spec from the PostHog API.
+    #[serde(default)]
    #[serde(skip_serializing_if = "Option::is_none")]
    #[serde(with = "humantime_serde")]
    pub refresh_interval: Option<Duration>,
 }

+impl PostHogConfig {
+    pub fn try_into_posthog_config(self) -> Result<PostHogClientConfig, &'static str> {
+        let Some(project_id) = self.project_id else {
+            return Err("project_id is required");
+        };
+        let Some(server_api_key) = self.server_api_key else {
+            return Err("server_api_key is required");
+        };
+        let Some(client_api_key) = self.client_api_key else {
+            return Err("client_api_key is required");
+        };
+        let Some(private_api_url) = self.private_api_url else {
+            return Err("private_api_url is required");
+        };
+        let Some(public_api_url) = self.public_api_url else {
+            return Err("public_api_url is required");
+        };
+        Ok(PostHogClientConfig {
+            project_id,
+            server_api_key,
+            client_api_key,
+            private_api_url,
+            public_api_url,
+        })
+    }
+}
+
 /// `pageserver.toml`
 ///
 /// We use serde derive with `#[serde(default)]` to generate a deserializer
@@ -367,6 +409,9 @@ pub struct BasebackupCacheConfig {
    // TODO(diko): support max_entry_size_bytes.
    // pub max_entry_size_bytes: u64,
    pub max_size_entries: usize,
+    /// Size of the channel used to send prepare requests to the basebackup cache worker.
+    /// If exceeded, new prepare requests will be dropped.
+    pub prepare_channel_size: usize,
 }

 impl Default for BasebackupCacheConfig {
@@ -375,7 +420,8 @@ impl Default for BasebackupCacheConfig {
            cleanup_period: Duration::from_secs(60),
            max_total_size_bytes: 1024 * 1024 * 1024, // 1 GiB
            // max_entry_size_bytes: 16 * 1024 * 1024,   // 16 MiB
-            max_size_entries: 1000,
+            max_size_entries: 10000,
+            prepare_channel_size: 100,
        }
    }
 }
--- a/libs/pageserver_api/src/controller_api.rs
+++ b/libs/pageserver_api/src/controller_api.rs
@@ -546,6 +546,11 @@ pub struct TimelineImportRequest {
    pub sk_set: Vec<NodeId>,
 }

+#[derive(serde::Serialize, serde::Deserialize, Clone)]
+pub struct TimelineSafekeeperMigrateRequest {
+    pub new_sk_set: Vec<NodeId>,
+}
+
 #[cfg(test)]
 mod test {
    use serde_json;
@@ -577,8 +582,7 @@ mod test {
        let err = serde_json::from_value::<TenantCreateRequest>(create_request).unwrap_err();
        assert!(
            err.to_string().contains("unknown field `unknown_field`"),
-            "expect unknown field `unknown_field` error, got: {}",
-            err
+            "expect unknown field `unknown_field` error, got: {err}"
        );
    }

--- a/libs/pageserver_api/src/keyspace.rs
+++ b/libs/pageserver_api/src/keyspace.rs
@@ -334,8 +334,7 @@ impl KeySpace {
                    std::cmp::max(range.start, prev.start) < std::cmp::min(range.end, prev.end);
                assert!(
                    !overlap,
-                    "Attempt to merge ovelapping keyspaces: {:?} overlaps {:?}",
-                    prev, range
+                    "Attempt to merge ovelapping keyspaces: {prev:?} overlaps {range:?}"
                );
            }

@@ -1104,7 +1103,7 @@ mod tests {
            // total range contains at least one shard-local page
            let all_nonzero = fragments.iter().all(|f| f.0 > 0);
            if !all_nonzero {
-                eprintln!("Found a zero-length fragment: {:?}", fragments);
+                eprintln!("Found a zero-length fragment: {fragments:?}");
            }
            assert!(all_nonzero);
        } else {
--- a/libs/pageserver_api/src/models.rs
+++ b/libs/pageserver_api/src/models.rs
@@ -11,6 +11,7 @@ use std::time::{Duration, SystemTime};

 #[cfg(feature = "testing")]
 use camino::Utf8PathBuf;
+use postgres_versioninfo::PgMajorVersion;
 use serde::{Deserialize, Deserializer, Serialize, Serializer};
 use serde_with::serde_as;
 pub use utilization::PageserverUtilization;
@@ -20,7 +21,9 @@ use utils::{completion, serde_system_time};

 use crate::config::Ratio;
 use crate::key::{CompactKey, Key};
-use crate::shard::{DEFAULT_STRIPE_SIZE, ShardCount, ShardStripeSize, TenantShardId};
+use crate::shard::{
+    DEFAULT_STRIPE_SIZE, ShardCount, ShardIdentity, ShardStripeSize, TenantShardId,
+};

 /// The state of a tenant in this pageserver.
 ///
@@ -398,7 +401,7 @@ pub enum TimelineCreateRequestMode {
        // inherits the ancestor's pg_version. Earlier code wasn't
        // using a flattened enum, so, it was an accepted field, and
        // we continue to accept it by having it here.
-        pg_version: Option<u32>,
+        pg_version: Option<PgMajorVersion>,
        #[serde(default, skip_serializing_if = "std::ops::Not::not")]
        read_only: bool,
    },
@@ -410,7 +413,7 @@ pub enum TimelineCreateRequestMode {
    Bootstrap {
        #[serde(default)]
        existing_initdb_timeline_id: Option<TimelineId>,
-        pg_version: Option<u32>,
+        pg_version: Option<PgMajorVersion>,
    },
 }

@@ -474,7 +477,7 @@ pub struct TenantShardSplitResponse {
 }

 /// Parameters that apply to all shards in a tenant.  Used during tenant creation.
-#[derive(Serialize, Deserialize, Debug)]
+#[derive(Clone, Copy, Serialize, Deserialize, Debug)]
 #[serde(deny_unknown_fields)]
 pub struct ShardParameters {
    pub count: ShardCount,
@@ -496,6 +499,15 @@ impl Default for ShardParameters {
    }
 }

+impl From<ShardIdentity> for ShardParameters {
+    fn from(identity: ShardIdentity) -> Self {
+        Self {
+            count: identity.count,
+            stripe_size: identity.stripe_size,
+        }
+    }
+}
+
 #[derive(Debug, Default, Clone, Eq, PartialEq)]
 pub enum FieldPatch<T> {
    Upsert(T),
@@ -1182,7 +1194,7 @@ impl Display for ImageCompressionAlgorithm {
            ImageCompressionAlgorithm::Disabled => write!(f, "disabled"),
            ImageCompressionAlgorithm::Zstd { level } => {
                if let Some(level) = level {
-                    write!(f, "zstd({})", level)
+                    write!(f, "zstd({level})")
                } else {
                    write!(f, "zstd")
                }
@@ -1573,7 +1585,7 @@ pub struct TimelineInfo {
    pub last_received_msg_lsn: Option<Lsn>,
    /// the timestamp (in microseconds) of the last received message
    pub last_received_msg_ts: Option<u128>,
-    pub pg_version: u32,
+    pub pg_version: PgMajorVersion,

    pub state: TimelineState,

@@ -2011,8 +2023,7 @@ mod tests {
        let err = serde_json::from_value::<TenantConfigRequest>(config_request).unwrap_err();
        assert!(
            err.to_string().contains("unknown field `unknown_field`"),
-            "expect unknown field `unknown_field` error, got: {}",
-            err
+            "expect unknown field `unknown_field` error, got: {err}"
        );
    }

--- a/libs/pageserver_api/src/shard.rs
+++ b/libs/pageserver_api/src/shard.rs
@@ -37,6 +37,7 @@ use std::hash::{Hash, Hasher};
 pub use ::utils::shard::*;
 use postgres_ffi_types::forknum::INIT_FORKNUM;
 use serde::{Deserialize, Serialize};
+use utils::critical;

 use crate::key::Key;
 use crate::models::ShardParameters;
@@ -179,7 +180,7 @@ impl ShardIdentity {

    /// For use when creating ShardIdentity instances for new shards, where a creation request
    /// specifies the ShardParameters that apply to all shards.
-    pub fn from_params(number: ShardNumber, params: &ShardParameters) -> Self {
+    pub fn from_params(number: ShardNumber, params: ShardParameters) -> Self {
        Self {
            number,
            count: params.count,
@@ -188,6 +189,17 @@ impl ShardIdentity {
        }
    }

+    /// Asserts that the given shard identities are equal. Changes to shard parameters will likely
+    /// result in data corruption.
+    pub fn assert_equal(&self, other: ShardIdentity) {
+        if self != &other {
+            // TODO: for now, we're conservative and just log errors in production. Turn this into a
+            // real assertion when we're confident it doesn't misfire, and also reject requests that
+            // attempt to change it with an error response.
+            critical!("shard identity mismatch: {self:?} != {other:?}");
+        }
+    }
+
    fn is_broken(&self) -> bool {
        self.layout == LAYOUT_BROKEN
    }
--- a/libs/postgres_backend/src/lib.rs
+++ b/libs/postgres_backend/src/lib.rs
@@ -939,7 +939,7 @@ impl<IO: AsyncRead + AsyncWrite + Unpin> PostgresBackendReader<IO> {
                FeMessage::CopyFail => Err(CopyStreamHandlerEnd::CopyFail),
                FeMessage::Terminate => Err(CopyStreamHandlerEnd::Terminate),
                _ => Err(CopyStreamHandlerEnd::from(ConnectionError::Protocol(
-                    ProtocolError::Protocol(format!("unexpected message in COPY stream {:?}", msg)),
+                    ProtocolError::Protocol(format!("unexpected message in COPY stream {msg:?}")),
                ))),
            },
            None => Err(CopyStreamHandlerEnd::EOF),
--- a/libs/postgres_backend/tests/simple_select.rs
+++ b/libs/postgres_backend/tests/simple_select.rs
@@ -61,7 +61,7 @@ async fn simple_select() {
    // so spawn it off to run on its own.
    tokio::spawn(async move {
        if let Err(e) = connection.await {
-            eprintln!("connection error: {}", e);
+            eprintln!("connection error: {e}");
        }
    });

@@ -137,7 +137,7 @@ async fn simple_select_ssl() {
    // so spawn it off to run on its own.
    tokio::spawn(async move {
        if let Err(e) = connection.await {
-            eprintln!("connection error: {}", e);
+            eprintln!("connection error: {e}");
        }
    });

--- a/libs/postgres_connection/src/lib.rs
+++ b/libs/postgres_connection/src/lib.rs
@@ -223,7 +223,7 @@ mod tests_pg_connection_config {
        assert_eq!(cfg.port(), 123);
        assert_eq!(cfg.raw_address(), "stub.host.example:123");
        assert_eq!(
-            format!("{:?}", cfg),
+            format!("{cfg:?}"),
            "PgConnectionConfig { host: Domain(\"stub.host.example\"), port: 123, password: None }"
        );
    }
@@ -239,7 +239,7 @@ mod tests_pg_connection_config {
        assert_eq!(cfg.port(), 123);
        assert_eq!(cfg.raw_address(), "[::1]:123");
        assert_eq!(
-            format!("{:?}", cfg),
+            format!("{cfg:?}"),
            "PgConnectionConfig { host: Ipv6(::1), port: 123, password: None }"
        );
    }
@@ -252,7 +252,7 @@ mod tests_pg_connection_config {
        assert_eq!(cfg.port(), 123);
        assert_eq!(cfg.raw_address(), "stub.host.example:123");
        assert_eq!(
-            format!("{:?}", cfg),
+            format!("{cfg:?}"),
            "PgConnectionConfig { host: Domain(\"stub.host.example\"), port: 123, password: Some(REDACTED-STRING) }"
        );
    }
--- a/libs/postgres_ffi/Cargo.toml
+++ b/libs/postgres_ffi/Cargo.toml
@@ -19,6 +19,7 @@ serde.workspace = true
 postgres_ffi_types.workspace = true
 utils.workspace = true
 tracing.workspace = true
+postgres_versioninfo.workspace = true

 [dev-dependencies]
 env_logger.workspace = true
--- a/libs/postgres_ffi/benches/waldecoder.rs
+++ b/libs/postgres_ffi/benches/waldecoder.rs
@@ -4,6 +4,7 @@ use criterion::{Bencher, Criterion, criterion_group, criterion_main};
 use postgres_ffi::v17::wal_generator::LogicalMessageGenerator;
 use postgres_ffi::v17::waldecoder_handler::WalStreamDecoderHandler;
 use postgres_ffi::waldecoder::WalStreamDecoder;
+use postgres_versioninfo::PgMajorVersion;
 use pprof::criterion::{Output, PProfProfiler};
 use utils::lsn::Lsn;

@@ -32,7 +33,7 @@ fn bench_complete_record(c: &mut Criterion) {
        let value_size = LogicalMessageGenerator::make_value_size(size, PREFIX);
        let value = vec![1; value_size];

-        let mut decoder = WalStreamDecoder::new(Lsn(0), 170000);
+        let mut decoder = WalStreamDecoder::new(Lsn(0), PgMajorVersion::PG17);
        let msg = LogicalMessageGenerator::new(PREFIX, &value)
            .next()
            .unwrap()
--- a/libs/postgres_ffi/src/lib.rs
+++ b/libs/postgres_ffi/src/lib.rs
@@ -14,6 +14,8 @@ use bytes::Bytes;
 use utils::bin_ser::SerializeError;
 use utils::lsn::Lsn;

+pub use postgres_versioninfo::PgMajorVersion;
+
 macro_rules! postgres_ffi {
    ($version:ident) => {
        #[path = "."]
@@ -91,21 +93,22 @@ macro_rules! dispatch_pgversion {
            $version => $code,
            default = $invalid_pgver_handling,
            pgversions = [
-                14 : v14,
-                15 : v15,
-                16 : v16,
-                17 : v17,
+                $crate::PgMajorVersion::PG14 => v14,
+                $crate::PgMajorVersion::PG15 => v15,
+                $crate::PgMajorVersion::PG16 => v16,
+                $crate::PgMajorVersion::PG17 => v17,
            ]
        )
    };
    ($pgversion:expr => $code:expr,
     default = $default:expr,
-     pgversions = [$($sv:literal : $vsv:ident),+ $(,)?]) => {
-        match ($pgversion) {
+     pgversions = [$($sv:pat => $vsv:ident),+ $(,)?]) => {
+        match ($pgversion.clone().into()) {
            $($sv => {
                use $crate::$vsv as pgv;
                $code
            },)+
+            #[allow(unreachable_patterns)]
            _ => {
                $default
            }
@@ -179,9 +182,9 @@ macro_rules! enum_pgversion {
            $($variant ( $crate::$md::$t )),+
        }
        impl self::$name {
-            pub fn pg_version(&self) -> u32 {
+            pub fn pg_version(&self) -> PgMajorVersion {
                enum_pgversion_dispatch!(self, $name, _ign, {
-                    pgv::bindings::PG_MAJORVERSION_NUM
+                    pgv::bindings::MY_PGVERSION
                })
            }
        }
@@ -195,15 +198,15 @@ macro_rules! enum_pgversion {
    };
    {name = $name:ident,
     path = $p:ident,
-     typ = $t:ident,
+     $(typ = $t:ident,)?
     pgversions = [$($variant:ident : $md:ident),+ $(,)?]} => {
        pub enum $name {
-            $($variant ($crate::$md::$p::$t)),+
+            $($variant $(($crate::$md::$p::$t))?),+
        }
        impl $name {
-            pub fn pg_version(&self) -> u32 {
+            pub fn pg_version(&self) -> PgMajorVersion {
                enum_pgversion_dispatch!(self, $name, _ign, {
-                    pgv::bindings::PG_MAJORVERSION_NUM
+                    pgv::bindings::MY_PGVERSION
                })
            }
        }
@@ -249,22 +252,21 @@ pub use v14::xlog_utils::{
    try_from_pg_timestamp,
 };

-pub fn bkpimage_is_compressed(bimg_info: u8, version: u32) -> bool {
+pub fn bkpimage_is_compressed(bimg_info: u8, version: PgMajorVersion) -> bool {
    dispatch_pgversion!(version, pgv::bindings::bkpimg_is_compressed(bimg_info))
 }

 pub fn generate_wal_segment(
    segno: u64,
    system_id: u64,
-    pg_version: u32,
+    pg_version: PgMajorVersion,
    lsn: Lsn,
 ) -> Result<Bytes, SerializeError> {
    assert_eq!(segno, lsn.segment_number(WAL_SEGMENT_SIZE));

    dispatch_pgversion!(
        pg_version,
-        pgv::xlog_utils::generate_wal_segment(segno, system_id, lsn),
-        Err(SerializeError::BadInput)
+        pgv::xlog_utils::generate_wal_segment(segno, system_id, lsn)
    )
 }

@@ -272,7 +274,7 @@ pub fn generate_pg_control(
    pg_control_bytes: &[u8],
    checkpoint_bytes: &[u8],
    lsn: Lsn,
-    pg_version: u32,
+    pg_version: PgMajorVersion,
 ) -> anyhow::Result<(Bytes, u64, bool)> {
    dispatch_pgversion!(
        pg_version,
@@ -352,6 +354,7 @@ pub fn fsm_logical_to_physical(addr: BlockNumber) -> BlockNumber {
 pub mod waldecoder {
    use std::num::NonZeroU32;

+    use crate::PgMajorVersion;
    use bytes::{Buf, Bytes, BytesMut};
    use thiserror::Error;
    use utils::lsn::Lsn;
@@ -369,7 +372,7 @@ pub mod waldecoder {

    pub struct WalStreamDecoder {
        pub lsn: Lsn,
-        pub pg_version: u32,
+        pub pg_version: PgMajorVersion,
        pub inputbuf: BytesMut,
        pub state: State,
    }
@@ -382,7 +385,7 @@ pub mod waldecoder {
    }

    impl WalStreamDecoder {
-        pub fn new(lsn: Lsn, pg_version: u32) -> WalStreamDecoder {
+        pub fn new(lsn: Lsn, pg_version: PgMajorVersion) -> WalStreamDecoder {
            WalStreamDecoder {
                lsn,
                pg_version,
--- a/libs/postgres_ffi/src/pg_constants_v14.rs
+++ b/libs/postgres_ffi/src/pg_constants_v14.rs
@@ -1,3 +1,7 @@
+use crate::PgMajorVersion;
+
+pub const MY_PGVERSION: PgMajorVersion = PgMajorVersion::PG14;
+
 pub const XLOG_DBASE_CREATE: u8 = 0x00;
 pub const XLOG_DBASE_DROP: u8 = 0x10;

--- a/libs/postgres_ffi/src/pg_constants_v15.rs
+++ b/libs/postgres_ffi/src/pg_constants_v15.rs
@@ -1,3 +1,7 @@
+use crate::PgMajorVersion;
+
+pub const MY_PGVERSION: PgMajorVersion = PgMajorVersion::PG15;
+
 pub const XACT_XINFO_HAS_DROPPED_STATS: u32 = 1u32 << 8;

 pub const XLOG_DBASE_CREATE_FILE_COPY: u8 = 0x00;
--- a/libs/postgres_ffi/src/pg_constants_v16.rs
+++ b/libs/postgres_ffi/src/pg_constants_v16.rs
@@ -1,3 +1,7 @@
+use crate::PgMajorVersion;
+
+pub const MY_PGVERSION: PgMajorVersion = PgMajorVersion::PG16;
+
 pub const XACT_XINFO_HAS_DROPPED_STATS: u32 = 1u32 << 8;

 pub const XLOG_DBASE_CREATE_FILE_COPY: u8 = 0x00;
--- a/libs/postgres_ffi/src/pg_constants_v17.rs
+++ b/libs/postgres_ffi/src/pg_constants_v17.rs
@@ -1,3 +1,7 @@
+use crate::PgMajorVersion;
+
+pub const MY_PGVERSION: PgMajorVersion = PgMajorVersion::PG17;
+
 pub const XACT_XINFO_HAS_DROPPED_STATS: u32 = 1u32 << 8;

 pub const XLOG_DBASE_CREATE_FILE_COPY: u8 = 0x00;
--- a/libs/postgres_ffi/src/waldecoder_handler.rs
+++ b/libs/postgres_ffi/src/waldecoder_handler.rs
@@ -114,7 +114,7 @@ impl WalStreamDecoderHandler for WalStreamDecoder {

                        let hdr = XLogLongPageHeaderData::from_bytes(&mut self.inputbuf).map_err(
                            |e| WalDecodeError {
-                                msg: format!("long header deserialization failed {}", e),
+                                msg: format!("long header deserialization failed {e}"),
                                lsn: self.lsn,
                            },
                        )?;
@@ -130,7 +130,7 @@ impl WalStreamDecoderHandler for WalStreamDecoder {
                        let hdr =
                            XLogPageHeaderData::from_bytes(&mut self.inputbuf).map_err(|e| {
                                WalDecodeError {
-                                    msg: format!("header deserialization failed {}", e),
+                                    msg: format!("header deserialization failed {e}"),
                                    lsn: self.lsn,
                                }
                            })?;
@@ -155,7 +155,7 @@ impl WalStreamDecoderHandler for WalStreamDecoder {
                    let xl_tot_len = (&self.inputbuf[0..4]).get_u32_le();
                    if (xl_tot_len as usize) < XLOG_SIZE_OF_XLOG_RECORD {
                        return Err(WalDecodeError {
-                            msg: format!("invalid xl_tot_len {}", xl_tot_len),
+                            msg: format!("invalid xl_tot_len {xl_tot_len}"),
                            lsn: self.lsn,
                        });
                    }
@@ -218,7 +218,7 @@ impl WalStreamDecoderHandler for WalStreamDecoder {
        let xlogrec =
            XLogRecord::from_slice(&recordbuf[0..XLOG_SIZE_OF_XLOG_RECORD]).map_err(|e| {
                WalDecodeError {
-                    msg: format!("xlog record deserialization failed {}", e),
+                    msg: format!("xlog record deserialization failed {e}"),
                    lsn: self.lsn,
                }
            })?;
--- a/libs/postgres_ffi/src/walrecord.rs
+++ b/libs/postgres_ffi/src/walrecord.rs
@@ -9,8 +9,8 @@ use utils::bin_ser::DeserializeError;
 use utils::lsn::Lsn;

 use crate::{
-    BLCKSZ, BlockNumber, MultiXactId, MultiXactOffset, MultiXactStatus, Oid, RepOriginId,
-    TimestampTz, TransactionId, XLOG_SIZE_OF_XLOG_RECORD, XLogRecord, pg_constants,
+    BLCKSZ, BlockNumber, MultiXactId, MultiXactOffset, MultiXactStatus, Oid, PgMajorVersion,
+    RepOriginId, TimestampTz, TransactionId, XLOG_SIZE_OF_XLOG_RECORD, XLogRecord, pg_constants,
 };

 #[repr(C)]
@@ -199,20 +199,17 @@ impl DecodedWALRecord {
    /// Check if this WAL record represents a legacy "copy" database creation, which populates new relations
    /// by reading other existing relations' data blocks.  This is more complex to apply than new-style database
    /// creations which simply include all the desired blocks in the WAL, so we need a helper function to detect this case.
-    pub fn is_dbase_create_copy(&self, pg_version: u32) -> bool {
+    pub fn is_dbase_create_copy(&self, pg_version: PgMajorVersion) -> bool {
        if self.xl_rmid == pg_constants::RM_DBASE_ID {
            let info = self.xl_info & pg_constants::XLR_RMGR_INFO_MASK;
            match pg_version {
-                14 => {
+                PgMajorVersion::PG14 => {
                    // Postgres 14 database creations are always the legacy kind
                    info == crate::v14::bindings::XLOG_DBASE_CREATE
                }
-                15 => info == crate::v15::bindings::XLOG_DBASE_CREATE_FILE_COPY,
-                16 => info == crate::v16::bindings::XLOG_DBASE_CREATE_FILE_COPY,
-                17 => info == crate::v17::bindings::XLOG_DBASE_CREATE_FILE_COPY,
-                _ => {
-                    panic!("Unsupported postgres version {pg_version}")
-                }
+                PgMajorVersion::PG15 => info == crate::v15::bindings::XLOG_DBASE_CREATE_FILE_COPY,
+                PgMajorVersion::PG16 => info == crate::v16::bindings::XLOG_DBASE_CREATE_FILE_COPY,
+                PgMajorVersion::PG17 => info == crate::v17::bindings::XLOG_DBASE_CREATE_FILE_COPY,
            }
        } else {
            false
@@ -248,7 +245,7 @@ impl DecodedWALRecord {
 pub fn decode_wal_record(
    record: Bytes,
    decoded: &mut DecodedWALRecord,
-    pg_version: u32,
+    pg_version: PgMajorVersion,
 ) -> anyhow::Result<()> {
    let mut rnode_spcnode: u32 = 0;
    let mut rnode_dbnode: u32 = 0;
@@ -1106,9 +1103,9 @@ pub struct XlClogTruncate {
 }

 impl XlClogTruncate {
-    pub fn decode(buf: &mut Bytes, pg_version: u32) -> XlClogTruncate {
+    pub fn decode(buf: &mut Bytes, pg_version: PgMajorVersion) -> XlClogTruncate {
        XlClogTruncate {
-            pageno: if pg_version < 17 {
+            pageno: if pg_version < PgMajorVersion::PG17 {
                buf.get_u32_le()
            } else {
                buf.get_u64_le() as u32
@@ -1199,7 +1196,7 @@ pub fn describe_postgres_wal_record(record: &Bytes) -> Result<String, Deserializ
                pg_constants::XLOG_HEAP2_MULTI_INSERT => "HEAP2 MULTI_INSERT",
                pg_constants::XLOG_HEAP2_VISIBLE => "HEAP2 VISIBLE",
                _ => {
-                    unknown_str = format!("HEAP2 UNKNOWN_0x{:02x}", info);
+                    unknown_str = format!("HEAP2 UNKNOWN_0x{info:02x}");
                    &unknown_str
                }
            }
@@ -1212,7 +1209,7 @@ pub fn describe_postgres_wal_record(record: &Bytes) -> Result<String, Deserializ
                pg_constants::XLOG_HEAP_UPDATE => "HEAP UPDATE",
                pg_constants::XLOG_HEAP_HOT_UPDATE => "HEAP HOT_UPDATE",
                _ => {
-                    unknown_str = format!("HEAP2 UNKNOWN_0x{:02x}", info);
+                    unknown_str = format!("HEAP2 UNKNOWN_0x{info:02x}");
                    &unknown_str
                }
            }
@@ -1223,7 +1220,7 @@ pub fn describe_postgres_wal_record(record: &Bytes) -> Result<String, Deserializ
                pg_constants::XLOG_FPI => "XLOG FPI",
                pg_constants::XLOG_FPI_FOR_HINT => "XLOG FPI_FOR_HINT",
                _ => {
-                    unknown_str = format!("XLOG UNKNOWN_0x{:02x}", info);
+                    unknown_str = format!("XLOG UNKNOWN_0x{info:02x}");
                    &unknown_str
                }
            }
@@ -1231,7 +1228,7 @@ pub fn describe_postgres_wal_record(record: &Bytes) -> Result<String, Deserializ
        rmid => {
            let info = xlogrec.xl_info & pg_constants::XLR_RMGR_INFO_MASK;

-            unknown_str = format!("UNKNOWN_RM_{} INFO_0x{:02x}", rmid, info);
+            unknown_str = format!("UNKNOWN_RM_{rmid} INFO_0x{info:02x}");
            &unknown_str
        }
    };
--- a/libs/postgres_ffi/src/xlog_utils.rs
+++ b/libs/postgres_ffi/src/xlog_utils.rs
@@ -11,9 +11,9 @@ use super::super::waldecoder::WalStreamDecoder;
 use super::bindings::{
    CheckPoint, ControlFileData, DBState_DB_SHUTDOWNED, FullTransactionId, TimeLineID, TimestampTz,
    XLogLongPageHeaderData, XLogPageHeaderData, XLogRecPtr, XLogRecord, XLogSegNo, XLOG_PAGE_MAGIC,
+    MY_PGVERSION
 };
 use super::wal_generator::LogicalMessageGenerator;
-use super::PG_MAJORVERSION;
 use crate::pg_constants;
 use crate::PG_TLI;
 use crate::{uint32, uint64, Oid};
@@ -233,7 +233,7 @@ pub fn find_end_of_wal(
    let mut result = start_lsn;
    let mut curr_lsn = start_lsn;
    let mut buf = [0u8; XLOG_BLCKSZ];
-    let pg_version = PG_MAJORVERSION[1..3].parse::<u32>().unwrap();
+    let pg_version = MY_PGVERSION;
    debug!("find_end_of_wal PG_VERSION: {}", pg_version);

    let mut decoder = WalStreamDecoder::new(start_lsn, pg_version);
--- a/libs/postgres_ffi/wal_craft/src/bin/wal_craft.rs
+++ b/libs/postgres_ffi/wal_craft/src/bin/wal_craft.rs
@@ -4,6 +4,7 @@ use std::str::FromStr;
 use anyhow::*;
 use clap::{Arg, ArgMatches, Command, value_parser};
 use postgres::Client;
+use postgres_ffi::PgMajorVersion;
 use wal_craft::*;

 fn main() -> Result<()> {
@@ -48,7 +49,7 @@ fn main() -> Result<()> {
        Some(("with-initdb", arg_matches)) => {
            let cfg = Conf {
                pg_version: *arg_matches
-                    .get_one::<u32>("pg-version")
+                    .get_one::<PgMajorVersion>("pg-version")
                    .context("'pg-version' is required")?,
                pg_distrib_dir: arg_matches
                    .get_one::<PathBuf>("pg-distrib-dir")
--- a/libs/postgres_ffi/wal_craft/src/lib.rs
+++ b/libs/postgres_ffi/wal_craft/src/lib.rs
@@ -9,8 +9,8 @@ use log::*;
 use postgres::Client;
 use postgres::types::PgLsn;
 use postgres_ffi::{
-    WAL_SEGMENT_SIZE, XLOG_BLCKSZ, XLOG_SIZE_OF_XLOG_LONG_PHD, XLOG_SIZE_OF_XLOG_RECORD,
-    XLOG_SIZE_OF_XLOG_SHORT_PHD,
+    PgMajorVersion, WAL_SEGMENT_SIZE, XLOG_BLCKSZ, XLOG_SIZE_OF_XLOG_LONG_PHD,
+    XLOG_SIZE_OF_XLOG_RECORD, XLOG_SIZE_OF_XLOG_SHORT_PHD,
 };

 macro_rules! xlog_utils_test {
@@ -29,7 +29,7 @@ macro_rules! xlog_utils_test {
 postgres_ffi::for_all_postgres_versions! { xlog_utils_test }

 pub struct Conf {
-    pub pg_version: u32,
+    pub pg_version: PgMajorVersion,
    pub pg_distrib_dir: PathBuf,
    pub datadir: PathBuf,
 }
@@ -52,11 +52,7 @@ impl Conf {
    pub fn pg_distrib_dir(&self) -> anyhow::Result<PathBuf> {
        let path = self.pg_distrib_dir.clone();

-        #[allow(clippy::manual_range_patterns)]
-        match self.pg_version {
-            14 | 15 | 16 | 17 => Ok(path.join(format!("v{}", self.pg_version))),
-            _ => bail!("Unsupported postgres version: {}", self.pg_version),
-        }
+        Ok(path.join(self.pg_version.v_str()))
    }

    fn pg_bin_dir(&self) -> anyhow::Result<PathBuf> {
--- a/libs/postgres_ffi/wal_craft/src/xlog_utils_test.rs
+++ b/libs/postgres_ffi/wal_craft/src/xlog_utils_test.rs
@@ -24,7 +24,7 @@ fn init_logging() {
 fn test_end_of_wal<C: crate::Crafter>(test_name: &str) {
    use crate::*;

-    let pg_version = PG_MAJORVERSION[1..3].parse::<u32>().unwrap();
+    let pg_version = MY_PGVERSION;

    // Craft some WAL
    let top_path = PathBuf::from(env!("CARGO_MANIFEST_DIR"))
@@ -34,7 +34,7 @@ fn test_end_of_wal<C: crate::Crafter>(test_name: &str) {
    let cfg = Conf {
        pg_version,
        pg_distrib_dir: top_path.join("pg_install"),
-        datadir: top_path.join(format!("test_output/{}-{PG_MAJORVERSION}", test_name)),
+        datadir: top_path.join(format!("test_output/{test_name}-{PG_MAJORVERSION}")),
    };
    if cfg.datadir.exists() {
        fs::remove_dir_all(&cfg.datadir).unwrap();
--- a/libs/postgres_initdb/Cargo.toml
+++ b/libs/postgres_initdb/Cargo.toml
@@ -9,4 +9,5 @@ anyhow.workspace = true
 tokio.workspace = true
 camino.workspace = true
 thiserror.workspace = true
+postgres_versioninfo.workspace = true
 workspace_hack = { version = "0.1", path = "../../workspace_hack" }
--- a/libs/postgres_initdb/src/lib.rs
+++ b/libs/postgres_initdb/src/lib.rs
@@ -7,12 +7,13 @@
 use std::fmt;

 use camino::Utf8Path;
+use postgres_versioninfo::PgMajorVersion;

 pub struct RunInitdbArgs<'a> {
    pub superuser: &'a str,
    pub locale: &'a str,
    pub initdb_bin: &'a Utf8Path,
-    pub pg_version: u32,
+    pub pg_version: PgMajorVersion,
    pub library_search_path: &'a Utf8Path,
    pub pgdata: &'a Utf8Path,
 }
@@ -31,15 +32,15 @@ pub enum Error {
 impl fmt::Display for Error {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match self {
-            Error::Spawn(e) => write!(f, "Error spawning command: {:?}", e),
+            Error::Spawn(e) => write!(f, "Error spawning command: {e:?}"),
            Error::Failed { status, stderr } => write!(
                f,
                "Command failed with status {:?}: {}",
                status,
                String::from_utf8_lossy(stderr)
            ),
-            Error::WaitOutput(e) => write!(f, "Error waiting for command output: {:?}", e),
-            Error::Other(e) => write!(f, "Error: {:?}", e),
+            Error::WaitOutput(e) => write!(f, "Error waiting for command output: {e:?}"),
+            Error::Other(e) => write!(f, "Error: {e:?}"),
        }
    }
 }
@@ -79,12 +80,16 @@ pub async fn do_run_initdb(args: RunInitdbArgs<'_>) -> Result<(), Error> {
        .stderr(std::process::Stdio::piped());

    // Before version 14, only the libc provide was available.
-    if pg_version > 14 {
+    if pg_version > PgMajorVersion::PG14 {
        // Version 17 brought with it a builtin locale provider which only provides
        // C and C.UTF-8. While being safer for collation purposes since it is
        // guaranteed to be consistent throughout a major release, it is also more
        // performant.
-        let locale_provider = if pg_version >= 17 { "builtin" } else { "libc" };
+        let locale_provider = if pg_version >= PgMajorVersion::PG17 {
+            "builtin"
+        } else {
+            "libc"
+        };

        initdb_command.args(["--locale-provider", locale_provider]);
    }
--- a/libs/postgres_versioninfo/Cargo.toml
+++ b/libs/postgres_versioninfo/Cargo.toml
@@ -0,0 +1,12 @@
+[package]
+name = "postgres_versioninfo"
+version = "0.1.0"
+edition = "2024"
+license.workspace = true
+
+[dependencies]
+anyhow.workspace = true
+thiserror.workspace = true
+serde.workspace = true
+serde_repr.workspace = true
+workspace_hack = { version = "0.1", path = "../../workspace_hack" }
--- a/libs/postgres_versioninfo/src/lib.rs
+++ b/libs/postgres_versioninfo/src/lib.rs
@@ -0,0 +1,175 @@
+use serde::{Deserialize, Deserializer, Serialize, Serializer};
+use serde_repr::{Deserialize_repr, Serialize_repr};
+use std::fmt::{Display, Formatter};
+use std::str::FromStr;
+
+/// An enum with one variant for each major version of PostgreSQL that we support.
+///
+#[derive(Debug, Clone, Copy, Ord, PartialOrd, Eq, PartialEq, Deserialize_repr, Serialize_repr)]
+#[repr(u32)]
+pub enum PgMajorVersion {
+    PG14 = 14,
+    PG15 = 15,
+    PG16 = 16,
+    PG17 = 17,
+    // !!! When you add a new PgMajorVersion, don't forget to update PgMajorVersion::ALL
+}
+
+/// A full PostgreSQL version ID, in MMmmbb numerical format (Major/minor/bugfix)
+#[derive(Debug, Copy, Clone, Ord, PartialOrd, Eq, PartialEq)]
+#[repr(transparent)]
+pub struct PgVersionId(u32);
+
+impl PgVersionId {
+    pub const UNKNOWN: PgVersionId = PgVersionId(0);
+
+    pub fn from_full_pg_version(version: u32) -> PgVersionId {
+        match version {
+            0 => PgVersionId(version), // unknown version
+            140000..180000 => PgVersionId(version),
+            _ => panic!("Invalid full PostgreSQL version ID {version}"),
+        }
+    }
+}
+
+impl Display for PgVersionId {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        u32::fmt(&self.0, f)
+    }
+}
+
+impl Serialize for PgVersionId {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        u32::serialize(&self.0, serializer)
+    }
+}
+
+impl<'de> Deserialize<'de> for PgVersionId {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        u32::deserialize(deserializer).map(PgVersionId)
+    }
+
+    fn deserialize_in_place<D>(deserializer: D, place: &mut Self) -> Result<(), D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        u32::deserialize_in_place(deserializer, &mut place.0)
+    }
+}
+
+impl PgMajorVersion {
+    /// Get the numerical representation of the represented Major Version
+    pub const fn major_version_num(&self) -> u32 {
+        match self {
+            PgMajorVersion::PG14 => 14,
+            PgMajorVersion::PG15 => 15,
+            PgMajorVersion::PG16 => 16,
+            PgMajorVersion::PG17 => 17,
+        }
+    }
+
+    /// Get the contents of this version's PG_VERSION file.
+    ///
+    /// The PG_VERSION file is used to determine the PostgreSQL version that currently
+    /// owns the data in a PostgreSQL data directory.
+    pub fn versionfile_string(&self) -> &'static str {
+        match self {
+            PgMajorVersion::PG14 => "14",
+            PgMajorVersion::PG15 => "15",
+            PgMajorVersion::PG16 => "16\x0A",
+            PgMajorVersion::PG17 => "17\x0A",
+        }
+    }
+
+    /// Get the v{version} string of this major PostgreSQL version.
+    ///
+    /// Because this was hand-coded in various places, this was moved into a shared
+    /// implementation.
+    pub fn v_str(&self) -> String {
+        match self {
+            PgMajorVersion::PG14 => "v14",
+            PgMajorVersion::PG15 => "v15",
+            PgMajorVersion::PG16 => "v16",
+            PgMajorVersion::PG17 => "v17",
+        }
+        .to_string()
+    }
+
+    /// All currently supported major versions of PostgreSQL.
+    pub const ALL: &'static [PgMajorVersion] = &[
+        PgMajorVersion::PG14,
+        PgMajorVersion::PG15,
+        PgMajorVersion::PG16,
+        PgMajorVersion::PG17,
+    ];
+}
+
+impl Display for PgMajorVersion {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        f.write_str(match self {
+            PgMajorVersion::PG14 => "PgMajorVersion::PG14",
+            PgMajorVersion::PG15 => "PgMajorVersion::PG15",
+            PgMajorVersion::PG16 => "PgMajorVersion::PG16",
+            PgMajorVersion::PG17 => "PgMajorVersion::PG17",
+        })
+    }
+}
+
+#[derive(Debug, thiserror::Error)]
+#[allow(dead_code)]
+pub struct InvalidPgVersion(u32);
+
+impl Display for InvalidPgVersion {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        write!(f, "InvalidPgVersion({})", self.0)
+    }
+}
+
+impl TryFrom<PgVersionId> for PgMajorVersion {
+    type Error = InvalidPgVersion;
+
+    fn try_from(value: PgVersionId) -> Result<Self, Self::Error> {
+        Ok(match value.0 / 10000 {
+            14 => PgMajorVersion::PG14,
+            15 => PgMajorVersion::PG15,
+            16 => PgMajorVersion::PG16,
+            17 => PgMajorVersion::PG17,
+            _ => return Err(InvalidPgVersion(value.0)),
+        })
+    }
+}
+
+impl From<PgMajorVersion> for PgVersionId {
+    fn from(value: PgMajorVersion) -> Self {
+        PgVersionId((value as u32) * 10000)
+    }
+}
+
+#[derive(Debug, PartialEq, Eq, thiserror::Error)]
+pub struct PgMajorVersionParseError(String);
+
+impl Display for PgMajorVersionParseError {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        write!(f, "PgMajorVersionParseError({})", self.0)
+    }
+}
+
+impl FromStr for PgMajorVersion {
+    type Err = PgMajorVersionParseError;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        Ok(match s {
+            "14" => PgMajorVersion::PG14,
+            "15" => PgMajorVersion::PG15,
+            "16" => PgMajorVersion::PG16,
+            "17" => PgMajorVersion::PG17,
+            _ => return Err(PgMajorVersionParseError(s.to_string())),
+        })
+    }
+}
--- a/libs/posthog_client_lite/src/background_loop.rs
+++ b/libs/posthog_client_lite/src/background_loop.rs
@@ -1,17 +1,22 @@
 //! A background loop that fetches feature flags from PostHog and updates the feature store.

-use std::{sync::Arc, time::Duration};
+use std::{
+    sync::Arc,
+    time::{Duration, SystemTime},
+};

 use arc_swap::ArcSwap;
 use tokio_util::sync::CancellationToken;
 use tracing::{Instrument, info_span};

-use crate::{CaptureEvent, FeatureStore, PostHogClient, PostHogClientConfig};
+use crate::{
+    CaptureEvent, FeatureStore, LocalEvaluationResponse, PostHogClient, PostHogClientConfig,
+};

 /// A background loop that fetches feature flags from PostHog and updates the feature store.
 pub struct FeatureResolverBackgroundLoop {
    posthog_client: PostHogClient,
-    feature_store: ArcSwap<FeatureStore>,
+    feature_store: ArcSwap<(SystemTime, Arc<FeatureStore>)>,
    cancel: CancellationToken,
 }

@@ -19,11 +24,35 @@ impl FeatureResolverBackgroundLoop {
    pub fn new(config: PostHogClientConfig, shutdown_pageserver: CancellationToken) -> Self {
        Self {
            posthog_client: PostHogClient::new(config),
-            feature_store: ArcSwap::new(Arc::new(FeatureStore::new())),
+            feature_store: ArcSwap::new(Arc::new((
+                SystemTime::UNIX_EPOCH,
+                Arc::new(FeatureStore::new()),
+            ))),
            cancel: shutdown_pageserver,
        }
    }

+    /// Update the feature store with a new feature flag spec bypassing the normal refresh loop.
+    pub fn update(&self, spec: String) -> anyhow::Result<()> {
+        let resp: LocalEvaluationResponse = serde_json::from_str(&spec)?;
+        self.update_feature_store_nofail(resp, "http_propagate");
+        Ok(())
+    }
+
+    fn update_feature_store_nofail(&self, resp: LocalEvaluationResponse, source: &'static str) {
+        let project_id = self.posthog_client.config.project_id.parse::<u64>().ok();
+        match FeatureStore::new_with_flags(resp.flags, project_id) {
+            Ok(feature_store) => {
+                self.feature_store
+                    .store(Arc::new((SystemTime::now(), Arc::new(feature_store))));
+                tracing::info!("Feature flag updated from {}", source);
+            }
+            Err(e) => {
+                tracing::warn!("Cannot process feature flag spec from {}: {}", source, e);
+            }
+        }
+    }
+
    pub fn spawn(
        self: Arc<Self>,
        handle: &tokio::runtime::Handle,
@@ -47,6 +76,17 @@ impl FeatureResolverBackgroundLoop {
                        _ = ticker.tick() => {}
                        _ = cancel.cancelled() => break
                    }
+                    {
+                        let last_update = this.feature_store.load().0;
+                        if let Ok(elapsed) = last_update.elapsed() {
+                            if elapsed < refresh_period {
+                                tracing::debug!(
+                                    "Skipping feature flag refresh because it's too soon"
+                                );
+                                continue;
+                            }
+                        }
+                    }
                    let resp = match this
                        .posthog_client
                        .get_feature_flags_local_evaluation()
@@ -58,16 +98,7 @@ impl FeatureResolverBackgroundLoop {
                            continue;
                        }
                    };
-                    let project_id = this.posthog_client.config.project_id.parse::<u64>().ok();
-                    match FeatureStore::new_with_flags(resp.flags, project_id) {
-                        Ok(feature_store) => {
-                            this.feature_store.store(Arc::new(feature_store));
-                            tracing::info!("Feature flag updated");
-                        }
-                        Err(e) => {
-                            tracing::warn!("Cannot process feature flag spec: {}", e);
-                        }
-                    }
+                    this.update_feature_store_nofail(resp, "refresh_loop");
                }
                tracing::info!("PostHog feature resolver stopped");
            }
@@ -92,6 +123,6 @@ impl FeatureResolverBackgroundLoop {
    }

    pub fn feature_store(&self) -> Arc<FeatureStore> {
-        self.feature_store.load_full()
+        self.feature_store.load().1.clone()
    }
 }
--- a/libs/posthog_client_lite/src/lib.rs
+++ b/libs/posthog_client_lite/src/lib.rs
@@ -168,15 +168,13 @@ impl FeatureStore {
                let PostHogFlagFilterPropertyValue::String(provided) = provided else {
                    // Left should be a string
                    return Err(PostHogEvaluationError::Internal(format!(
-                        "The left side of the condition is not a string: {:?}",
-                        provided
+                        "The left side of the condition is not a string: {provided:?}"
                    )));
                };
                let PostHogFlagFilterPropertyValue::List(requested) = requested else {
                    // Right should be a list of string
                    return Err(PostHogEvaluationError::Internal(format!(
-                        "The right side of the condition is not a list: {:?}",
-                        requested
+                        "The right side of the condition is not a list: {requested:?}"
                    )));
                };
                Ok(requested.contains(provided))
@@ -185,14 +183,12 @@ impl FeatureStore {
                let PostHogFlagFilterPropertyValue::String(requested) = requested else {
                    // Right should be a string
                    return Err(PostHogEvaluationError::Internal(format!(
-                        "The right side of the condition is not a string: {:?}",
-                        requested
+                        "The right side of the condition is not a string: {requested:?}"
                    )));
                };
                let Ok(requested) = requested.parse::<f64>() else {
                    return Err(PostHogEvaluationError::Internal(format!(
-                        "Can not parse the right side of the condition as a number: {:?}",
-                        requested
+                        "Can not parse the right side of the condition as a number: {requested:?}"
                    )));
                };
                // Left can either be a number or a string
@@ -201,16 +197,14 @@ impl FeatureStore {
                    PostHogFlagFilterPropertyValue::String(provided) => {
                        let Ok(provided) = provided.parse::<f64>() else {
                            return Err(PostHogEvaluationError::Internal(format!(
-                                "Can not parse the left side of the condition as a number: {:?}",
-                                provided
+                                "Can not parse the left side of the condition as a number: {provided:?}"
                            )));
                        };
                        provided
                    }
                    _ => {
                        return Err(PostHogEvaluationError::Internal(format!(
-                            "The left side of the condition is not a number or a string: {:?}",
-                            provided
+                            "The left side of the condition is not a number or a string: {provided:?}"
                        )));
                    }
                };
@@ -218,14 +212,12 @@ impl FeatureStore {
                    "lt" => Ok(provided < requested),
                    "gt" => Ok(provided > requested),
                    op => Err(PostHogEvaluationError::Internal(format!(
-                        "Unsupported operator: {}",
-                        op
+                        "Unsupported operator: {op}"
                    ))),
                }
            }
            _ => Err(PostHogEvaluationError::Internal(format!(
-                "Unsupported operator: {}",
-                operator
+                "Unsupported operator: {operator}"
            ))),
        }
    }
@@ -373,8 +365,7 @@ impl FeatureStore {
        if let Some(flag_config) = self.flags.get(flag_key) {
            if !flag_config.active {
                return Err(PostHogEvaluationError::NotAvailable(format!(
-                    "The feature flag is not active: {}",
-                    flag_key
+                    "The feature flag is not active: {flag_key}"
                )));
            }
            let Some(ref multivariate) = flag_config.filters.multivariate else {
@@ -401,8 +392,7 @@ impl FeatureStore {
                        // This should not happen because the rollout percentage always adds up to 100, but just in case that PostHog
                        // returned invalid spec, we return an error.
                        return Err(PostHogEvaluationError::Internal(format!(
-                            "Rollout percentage does not add up to 100: {}",
-                            flag_key
+                            "Rollout percentage does not add up to 100: {flag_key}"
                        )));
                    }
                    GroupEvaluationResult::Unmatched => continue,
@@ -413,8 +403,7 @@ impl FeatureStore {
        } else {
            // The feature flag is not available yet
            Err(PostHogEvaluationError::NotAvailable(format!(
-                "Not found in the local evaluation spec: {}",
-                flag_key
+                "Not found in the local evaluation spec: {flag_key}"
            )))
        }
    }
@@ -440,8 +429,7 @@ impl FeatureStore {
        if let Some(flag_config) = self.flags.get(flag_key) {
            if !flag_config.active {
                return Err(PostHogEvaluationError::NotAvailable(format!(
-                    "The feature flag is not active: {}",
-                    flag_key
+                    "The feature flag is not active: {flag_key}"
                )));
            }
            if flag_config.filters.multivariate.is_some() {
@@ -456,8 +444,7 @@ impl FeatureStore {
                match self.evaluate_group(group, hash_on_global_rollout_percentage, properties)? {
                    GroupEvaluationResult::MatchedAndOverride(_) => {
                        return Err(PostHogEvaluationError::Internal(format!(
-                            "Boolean flag cannot have overrides: {}",
-                            flag_key
+                            "Boolean flag cannot have overrides: {flag_key}"
                        )));
                    }
                    GroupEvaluationResult::MatchedAndEvaluate => {
@@ -471,8 +458,7 @@ impl FeatureStore {
        } else {
            // The feature flag is not available yet
            Err(PostHogEvaluationError::NotAvailable(format!(
-                "Not found in the local evaluation spec: {}",
-                flag_key
+                "Not found in the local evaluation spec: {flag_key}"
            )))
        }
    }
@@ -483,8 +469,7 @@ impl FeatureStore {
            Ok(flag_config.filters.multivariate.is_none())
        } else {
            Err(PostHogEvaluationError::NotAvailable(format!(
-                "Not found in the local evaluation spec: {}",
-                flag_key
+                "Not found in the local evaluation spec: {flag_key}"
            )))
        }
    }
@@ -559,17 +544,8 @@ impl PostHogClient {
        self.config.server_api_key.starts_with("phs_")
    }

-    /// Fetch the feature flag specs from the server.
-    ///
-    /// This is unfortunately an undocumented API at:
-    /// - <https://posthog.com/docs/api/feature-flags#get-api-projects-project_id-feature_flags-local_evaluation>
-    /// - <https://posthog.com/docs/feature-flags/local-evaluation>
-    ///
-    /// The handling logic in [`FeatureStore`] mostly follows the Python API implementation.
-    /// See `_compute_flag_locally` in <https://github.com/PostHog/posthog-python/blob/master/posthog/client.py>
-    pub async fn get_feature_flags_local_evaluation(
-        &self,
-    ) -> anyhow::Result<LocalEvaluationResponse> {
+    /// Get the raw JSON spec, same as `get_feature_flags_local_evaluation` but without parsing.
+    pub async fn get_feature_flags_local_evaluation_raw(&self) -> anyhow::Result<String> {
        // BASE_URL/api/projects/:project_id/feature_flags/local_evaluation
        // with bearer token of self.server_api_key
        // OR
@@ -603,7 +579,22 @@ impl PostHogClient {
                body
            ));
        }
-        Ok(serde_json::from_str(&body)?)
+        Ok(body)
+    }
+
+    /// Fetch the feature flag specs from the server.
+    ///
+    /// This is unfortunately an undocumented API at:
+    /// - <https://posthog.com/docs/api/feature-flags#get-api-projects-project_id-feature_flags-local_evaluation>
+    /// - <https://posthog.com/docs/feature-flags/local-evaluation>
+    ///
+    /// The handling logic in [`FeatureStore`] mostly follows the Python API implementation.
+    /// See `_compute_flag_locally` in <https://github.com/PostHog/posthog-python/blob/master/posthog/client.py>
+    pub async fn get_feature_flags_local_evaluation(
+        &self,
+    ) -> Result<LocalEvaluationResponse, anyhow::Error> {
+        let raw = self.get_feature_flags_local_evaluation_raw().await?;
+        Ok(serde_json::from_str(&raw)?)
    }

    /// Capture an event. This will only be used to report the feature flag usage back to PostHog, though
--- a/Show More
+++ b/Show More