Add comment about using mdnblocks to prevent race condition

Use mdnblocks to prevent raqce condition during end of unlogged build
impr(compute): Remove the deprecated CLI arg alias for remote-ext-config. (#12087 )
2026-02-19 02:20:37 +00:00 · 2025-06-16 18:22:49 +03:00 · 2025-05-31 20:44:58 +03:00 · 2025-05-30 17:45:24 +00:00 · 2025-05-30 17:00:41 +00:00 · 2025-05-30 15:26:22 +00:00
146 changed files with 7539 additions and 2604 deletions
--- a/.github/workflows/build_and_test.yml
+++ b/.github/workflows/build_and_test.yml
@@ -314,7 +314,8 @@ jobs:
          test_selection: performance
          run_in_parallel: false
          save_perf_report: ${{ github.ref_name == 'main' }}
-          extra_params: --splits 5 --group ${{ matrix.pytest_split_group }}
+          # test_pageserver_max_throughput_getpage_at_latest_lsn is run in separate workflow periodic_pagebench.yml because it needs snapshots
+          extra_params: --splits 5 --group ${{ matrix.pytest_split_group }} --ignore=test_runner/performance/pageserver/pagebench/test_pageserver_max_throughput_getpage_at_latest_lsn.py
          benchmark_durations: ${{ needs.get-benchmarks-durations.outputs.json }}
          pg_version: v16
          aws-oidc-role-arn: ${{ vars.DEV_AWS_OIDC_ROLE_ARN }}
--- a/.github/workflows/periodic_pagebench.yml
+++ b/.github/workflows/periodic_pagebench.yml
@@ -1,4 +1,4 @@
-name: Periodic pagebench performance test on dedicated EC2 machine in eu-central-1 region
+name: Periodic pagebench performance test on unit-perf hetzner runner

 on:
  schedule:
@@ -8,7 +8,7 @@ on:
    #        │   │ ┌───────────── day of the month (1 - 31)
    #        │   │ │ ┌───────────── month (1 - 12 or JAN-DEC)
    #        │   │ │ │ ┌───────────── day of the week (0 - 6 or SUN-SAT)
-    - cron: '0 */3 * * *' # Runs every 3 hours
+    - cron: '0 */4 * * *' # Runs every 4 hours
  workflow_dispatch: # Allows manual triggering of the workflow
    inputs:
      commit_hash:
@@ -16,6 +16,11 @@ on:
        description: 'The long neon repo commit hash for the system under test (pageserver) to be tested.'
        required: false
        default: ''
+      recreate_snapshots:
+        type: boolean
+        description: 'Recreate snapshots - !!!WARNING!!! We should only recreate snapshots if the previous ones are no longer compatible. Otherwise benchmarking results are not comparable across runs.'
+        required: false
+        default: false

 defaults:
  run:
@@ -29,13 +34,13 @@ permissions:
  contents: read

 jobs:
-  trigger_bench_on_ec2_machine_in_eu_central_1:
+  run_periodic_pagebench_test:
    permissions:
      id-token: write # aws-actions/configure-aws-credentials
      statuses: write
      contents: write
      pull-requests: write
-    runs-on: [ self-hosted, small ]
+    runs-on: [ self-hosted, unit-perf ]
    container:
      image: ghcr.io/neondatabase/build-tools:pinned-bookworm
      credentials:
@@ -44,10 +49,13 @@ jobs:
      options: --init
    timeout-minutes: 360  # Set the timeout to 6 hours
    env:
-      API_KEY: ${{ secrets.PERIODIC_PAGEBENCH_EC2_RUNNER_API_KEY }}
      RUN_ID: ${{ github.run_id }}
-      AWS_DEFAULT_REGION : "eu-central-1"
-      AWS_INSTANCE_ID : "i-02a59a3bf86bc7e74"
+      DEFAULT_PG_VERSION: 16
+      BUILD_TYPE: release
+      RUST_BACKTRACE: 1
+      # NEON_ENV_BUILDER_USE_OVERLAYFS_FOR_SNAPSHOTS: 1 - doesn't work without root in container
+      S3_BUCKET: neon-github-public-dev
+      PERF_TEST_RESULT_CONNSTR: "${{ secrets.PERF_TEST_RESULT_CONNSTR }}"
    steps:
    # we don't need the neon source code because we run everything remotely
    # however we still need the local github actions to run the allure step below
@@ -56,99 +64,194 @@ jobs:
      with:
        egress-policy: audit

-    - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+    - name: Set up the environment which depends on $RUNNER_TEMP on nvme drive
+      id: set-env
+      shell: bash -euxo pipefail {0}
+      run: |
+        {
+          echo "NEON_DIR=${RUNNER_TEMP}/neon"
+          echo "NEON_BIN=${RUNNER_TEMP}/neon/bin"
+          echo "POSTGRES_DISTRIB_DIR=${RUNNER_TEMP}/neon/pg_install"
+          echo "LD_LIBRARY_PATH=${RUNNER_TEMP}/neon/pg_install/v${DEFAULT_PG_VERSION}/lib"
+          echo "BACKUP_DIR=${RUNNER_TEMP}/instance_store/saved_snapshots"
+          echo "TEST_OUTPUT=${RUNNER_TEMP}/neon/test_output"
+          echo "PERF_REPORT_DIR=${RUNNER_TEMP}/neon/test_output/perf-report-local"
+          echo "ALLURE_DIR=${RUNNER_TEMP}/neon/test_output/allure-results"
+          echo "ALLURE_RESULTS_DIR=${RUNNER_TEMP}/neon/test_output/allure-results/results"
+        } >> "$GITHUB_ENV"

-    - name: Show my own (github runner) external IP address - usefull for IP allowlisting
-      run: curl https://ifconfig.me
+        echo "allure_results_dir=${RUNNER_TEMP}/neon/test_output/allure-results/results" >> "$GITHUB_OUTPUT"

-    - name: Assume AWS OIDC role that allows to manage (start/stop/describe... EC machine)
-      uses: aws-actions/configure-aws-credentials@e3dd6a429d7300a6a4c196c26e071d42e0343502 # v4.0.2
+    - uses: aws-actions/configure-aws-credentials@e3dd6a429d7300a6a4c196c26e071d42e0343502 # v4.0.2
      with:
        aws-region: eu-central-1
-        role-to-assume: ${{ vars.DEV_AWS_OIDC_ROLE_MANAGE_BENCHMARK_EC2_VMS_ARN }}
-        role-duration-seconds: 3600
-
-    - name: Start EC2 instance and wait for the instance to boot up
-      run: |
-        aws ec2 start-instances --instance-ids $AWS_INSTANCE_ID
-        aws ec2 wait instance-running --instance-ids $AWS_INSTANCE_ID
-        sleep 60 # sleep some time to allow cloudinit and our API server to start up
-
-    - name: Determine public IP of the EC2 instance and set env variable EC2_MACHINE_URL_US
-      run: |
-        public_ip=$(aws ec2 describe-instances --instance-ids $AWS_INSTANCE_ID --query 'Reservations[*].Instances[*].PublicIpAddress' --output text)
-        echo "Public IP of the EC2 instance: $public_ip"
-        echo "EC2_MACHINE_URL_US=https://${public_ip}:8443" >> $GITHUB_ENV
-
+        role-to-assume: ${{ vars.DEV_AWS_OIDC_ROLE_ARN }}
+        role-duration-seconds: 18000 # max 5 hours (needed in case commit hash is still being built)
    - name: Determine commit hash
+      id: commit_hash
+      shell: bash -euxo pipefail {0}
      env:
        INPUT_COMMIT_HASH: ${{ github.event.inputs.commit_hash }}
      run: |
-        if [ -z "$INPUT_COMMIT_HASH" ]; then
-          echo "COMMIT_HASH=$(curl -s https://api.github.com/repos/neondatabase/neon/commits/main | jq -r '.sha')" >> $GITHUB_ENV
+        if [[ -z "${INPUT_COMMIT_HASH}" ]]; then
+          COMMIT_HASH=$(curl -s https://api.github.com/repos/neondatabase/neon/commits/main | jq -r '.sha')
+          echo "COMMIT_HASH=$COMMIT_HASH" >> $GITHUB_ENV
+          echo "commit_hash=$COMMIT_HASH" >> "$GITHUB_OUTPUT"
          echo "COMMIT_HASH_TYPE=latest" >> $GITHUB_ENV
        else
-          echo "COMMIT_HASH=$INPUT_COMMIT_HASH" >> $GITHUB_ENV
+          COMMIT_HASH="${INPUT_COMMIT_HASH}"
+          echo "COMMIT_HASH=$COMMIT_HASH" >> $GITHUB_ENV
+          echo "commit_hash=$COMMIT_HASH" >> "$GITHUB_OUTPUT"
          echo "COMMIT_HASH_TYPE=manual" >> $GITHUB_ENV
        fi
+    - name: Checkout the neon repository at given commit hash
+      uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      with:
+        ref: ${{ steps.commit_hash.outputs.commit_hash }}

-    - name: Start Bench with run_id
+    # does not reuse ./.github/actions/download because we need to download the artifact for the given commit hash
+    # example artifact
+    # s3://neon-github-public-dev/artifacts/48b870bc078bd2c450eb7b468e743b9c118549bf/15036827400/1/neon-Linux-X64-release-artifact.tar.zst /instance_store/artifacts/neon-Linux-release-artifact.tar.zst
+    - name: Determine artifact S3_KEY for given commit hash and download and extract artifact
+      id: artifact_prefix
+      shell: bash -euxo pipefail {0}
+      env:
+        ARCHIVE: ${{ runner.temp }}/downloads/neon-${{ runner.os }}-${{ runner.arch }}-release-artifact.tar.zst
+        COMMIT_HASH: ${{ env.COMMIT_HASH }}
+        COMMIT_HASH_TYPE: ${{ env.COMMIT_HASH_TYPE }}
      run: |
-        curl -k -X 'POST' \
-        "${EC2_MACHINE_URL_US}/start_test/${GITHUB_RUN_ID}" \
-        -H 'accept: application/json' \
-        -H 'Content-Type: application/json' \
-        -H "Authorization: Bearer $API_KEY" \
-        -d "{\"neonRepoCommitHash\": \"${COMMIT_HASH}\", \"neonRepoCommitHashType\": \"${COMMIT_HASH_TYPE}\"}"
+        attempt=0
+        max_attempts=24 # 5 minutes * 24 = 2 hours

-    - name: Poll Test Status
-      id: poll_step
-      run: |
-        status=""
-        while [[ "$status" != "failure" && "$status" != "success" ]]; do
-          response=$(curl -k -X 'GET' \
-          "${EC2_MACHINE_URL_US}/test_status/${GITHUB_RUN_ID}" \
-          -H 'accept: application/json' \
-          -H "Authorization: Bearer $API_KEY")
-          echo "Response: $response"
-          set +x
-          status=$(echo $response | jq -r '.status')
-          echo "Test status: $status"
-          if [[ "$status" == "failure" ]]; then
-            echo "Test failed"
-            exit 1 # Fail the job step if status is failure
-          elif [[ "$status" == "success" || "$status" == "null" ]]; then
+        while [[ $attempt -lt $max_attempts ]]; do
+          # the following command will fail until the artifacts are available ...
+          S3_KEY=$(aws s3api list-objects-v2 --bucket "$S3_BUCKET" --prefix "artifacts/$COMMIT_HASH/" \
+            | jq -r '.Contents[]?.Key' \
+            | grep "neon-${{ runner.os }}-${{ runner.arch }}-release-artifact.tar.zst" \
+            | sort --version-sort \
+            | tail -1) || true # ... thus ignore errors from the command
+          if [[ -n "${S3_KEY}" ]]; then
+            echo "Artifact found: $S3_KEY"
+            echo "S3_KEY=$S3_KEY" >> $GITHUB_ENV
            break
-          elif [[ "$status" == "too_many_runs" ]]; then
-            echo "Too many runs already running"
-            echo "too_many_runs=true" >> "$GITHUB_OUTPUT"
-            exit 1
          fi
-
-          sleep 60 # Poll every 60 seconds
+          
+          # Increment attempt counter and sleep for 5 minutes
+          attempt=$((attempt + 1))
+          echo "Attempt $attempt of $max_attempts to find artifacts in S3 bucket s3://$S3_BUCKET/artifacts/$COMMIT_HASH failed. Retrying in 5 minutes..."
+          sleep 300 # Sleep for 5 minutes
        done

-    - name: Retrieve Test Logs
-      if: always() && steps.poll_step.outputs.too_many_runs != 'true'
-      run: |
-        curl -k -X 'GET' \
-        "${EC2_MACHINE_URL_US}/test_log/${GITHUB_RUN_ID}" \
-        -H 'accept: application/gzip' \
-        -H "Authorization: Bearer $API_KEY" \
-        --output "test_log_${GITHUB_RUN_ID}.gz"
+        if [[ -z "${S3_KEY}" ]]; then
+          echo "Error: artifact not found in S3 bucket s3://$S3_BUCKET/artifacts/$COMMIT_HASH" after 2 hours
+        else
+          mkdir -p $(dirname $ARCHIVE)
+          time aws s3 cp --only-show-errors s3://$S3_BUCKET/${S3_KEY} ${ARCHIVE}
+          mkdir -p ${NEON_DIR}
+          time tar -xf ${ARCHIVE} -C ${NEON_DIR}
+          rm -f ${ARCHIVE}
+        fi

-    - name: Unzip Test Log and Print it into this job's log
-      if: always() && steps.poll_step.outputs.too_many_runs != 'true'
+    - name: Download snapshots from S3
+      if: ${{ github.event_name != 'workflow_dispatch' || github.event.inputs.recreate_snapshots == 'false' || github.event.inputs.recreate_snapshots == '' }}
+      id: download_snapshots
+      shell: bash -euxo pipefail {0}
      run: |
-        gzip -d "test_log_${GITHUB_RUN_ID}.gz"
-        cat "test_log_${GITHUB_RUN_ID}"
+        # Download the snapshots from S3
+        mkdir -p ${TEST_OUTPUT}
+        mkdir -p $BACKUP_DIR
+        cd $BACKUP_DIR
+        mkdir parts
+        cd parts
+        PART=$(aws s3api list-objects-v2 --bucket $S3_BUCKET --prefix performance/pagebench/ \
+          | jq -r '.Contents[]?.Key' \
+          | grep -E 'shared-snapshots-[0-9]{4}-[0-9]{2}-[0-9]{2}' \
+          | sort \
+          | tail -1)
+        echo "Latest PART: $PART"
+        if [[ -z "$PART" ]]; then
+          echo "ERROR: No matching S3 key found" >&2
+          exit 1
+        fi
+        S3_KEY=$(dirname $PART)
+        time aws s3 cp --only-show-errors --recursive s3://${S3_BUCKET}/$S3_KEY/ .
+        cd $TEST_OUTPUT
+        time cat $BACKUP_DIR/parts/* | zstdcat | tar --extract --preserve-permissions
+        rm -rf ${BACKUP_DIR}
+
+    - name: Cache poetry deps
+      uses: actions/cache@v4
+      with:
+        path: ~/.cache/pypoetry/virtualenvs
+        key: v2-${{ runner.os }}-${{ runner.arch }}-python-deps-bookworm-${{ hashFiles('poetry.lock') }}
+
+    - name: Install Python deps
+      shell: bash -euxo pipefail {0}
+      run: ./scripts/pysync
+
+    # we need high number of open files for pagebench
+    - name: show ulimits
+      shell: bash -euxo pipefail {0}
+      run: |
+        ulimit -a
+
+    - name: Run pagebench testcase
+      shell: bash -euxo pipefail {0}
+      env:
+        CI: false  # need to override this env variable set by github to enforce using snapshots
+      run: |
+        export PLATFORM=hetzner-unit-perf-${COMMIT_HASH_TYPE}
+        # report the commit hash of the neon repository in the revision of the test results
+        export GITHUB_SHA=${COMMIT_HASH}
+        rm -rf ${PERF_REPORT_DIR}
+        rm -rf ${ALLURE_RESULTS_DIR}
+        mkdir -p ${PERF_REPORT_DIR}
+        mkdir -p ${ALLURE_RESULTS_DIR}
+        PARAMS="--alluredir=${ALLURE_RESULTS_DIR} --tb=short --verbose -rA"
+        EXTRA_PARAMS="--out-dir ${PERF_REPORT_DIR} --durations-path $TEST_OUTPUT/benchmark_durations.json"
+        # run only two selected tests
+        # environment set by parent:
+        # RUST_BACKTRACE=1 DEFAULT_PG_VERSION=16 BUILD_TYPE=release
+        ./scripts/pytest ${PARAMS} test_runner/performance/pageserver/pagebench/test_pageserver_max_throughput_getpage_at_latest_lsn.py::test_pageserver_characterize_throughput_with_n_tenants ${EXTRA_PARAMS}
+        ./scripts/pytest ${PARAMS} test_runner/performance/pageserver/pagebench/test_pageserver_max_throughput_getpage_at_latest_lsn.py::test_pageserver_characterize_latencies_with_1_client_and_throughput_with_many_clients_one_tenant ${EXTRA_PARAMS}
+
+    - name: upload the performance metrics to the Neon performance database which is used by grafana dashboards to display the results
+      shell: bash -euxo pipefail {0}
+      run: |
+        export REPORT_FROM="$PERF_REPORT_DIR"
+        export GITHUB_SHA=${COMMIT_HASH}
+        time ./scripts/generate_and_push_perf_report.sh
+
+    - name: Upload test results
+      if: ${{ !cancelled() }}
+      uses: ./.github/actions/allure-report-store
+      with:
+        report-dir:  ${{ steps.set-env.outputs.allure_results_dir }}
+        unique-key: ${{ env.BUILD_TYPE }}-${{ env.DEFAULT_PG_VERSION }}-${{ runner.arch }}
+        aws-oidc-role-arn:  ${{ vars.DEV_AWS_OIDC_ROLE_ARN }}

    - name: Create Allure report
+      id: create-allure-report
      if: ${{ !cancelled() }}
      uses: ./.github/actions/allure-report-generate
      with:
        aws-oidc-role-arn: ${{ vars.DEV_AWS_OIDC_ROLE_ARN }}

+    - name: Upload snapshots
+      if: ${{ github.event_name == 'workflow_dispatch' && github.event.inputs.recreate_snapshots != 'false' && github.event.inputs.recreate_snapshots != '' }}
+      id: upload_snapshots
+      shell: bash -euxo pipefail {0}
+      run: |
+        mkdir -p $BACKUP_DIR
+        cd $TEST_OUTPUT
+        tar --create --preserve-permissions --file - shared-snapshots | zstd -o $BACKUP_DIR/shared_snapshots.tar.zst
+        cd $BACKUP_DIR
+        mkdir parts
+        split -b 1G shared_snapshots.tar.zst ./parts/shared_snapshots.tar.zst.part.
+        SNAPSHOT_DATE=$(date +%F)  # YYYY-MM-DD
+        cd parts
+        time aws s3 cp --recursive . s3://${S3_BUCKET}/performance/pagebench/shared-snapshots-${SNAPSHOT_DATE}/
+
    - name: Post to a Slack channel
      if: ${{ github.event.schedule && failure() }}
      uses: slackapi/slack-github-action@fcfb566f8b0aab22203f066d80ca1d7e4b5d05b3 # v1.27.1
@@ -157,26 +260,22 @@ jobs:
        slack-message: "Periodic pagebench testing on dedicated hardware: ${{ job.status }}\n${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}"
      env:
        SLACK_BOT_TOKEN: ${{ secrets.SLACK_BOT_TOKEN }}
-
+        
    - name: Cleanup Test Resources
      if: always()
+      shell: bash -euxo pipefail {0}
+      env:
+        ARCHIVE: ${{ runner.temp }}/downloads/neon-${{ runner.os }}-${{ runner.arch }}-release-artifact.tar.zst
      run: |
-        curl -k -X 'POST' \
-        "${EC2_MACHINE_URL_US}/cleanup_test/${GITHUB_RUN_ID}" \
-        -H 'accept: application/json' \
-        -H "Authorization: Bearer $API_KEY" \
-        -d ''
+        # Cleanup the test resources
+        if [[ -d "${BACKUP_DIR}" ]]; then
+          rm -rf ${BACKUP_DIR}
+        fi
+        if [[ -d "${TEST_OUTPUT}" ]]; then
+          rm -rf ${TEST_OUTPUT}
+        fi
+        if [[ -d "${NEON_DIR}" ]]; then
+          rm -rf ${NEON_DIR}
+        fi
+        rm -rf $(dirname $ARCHIVE)

-    - name: Assume AWS OIDC role that allows to manage (start/stop/describe... EC machine)
-      if: always() && steps.poll_step.outputs.too_many_runs != 'true'
-      uses: aws-actions/configure-aws-credentials@e3dd6a429d7300a6a4c196c26e071d42e0343502 # v4.0.2
-      with:
-        aws-region: eu-central-1
-        role-to-assume: ${{ vars.DEV_AWS_OIDC_ROLE_MANAGE_BENCHMARK_EC2_VMS_ARN }}
-        role-duration-seconds: 3600
-
-    - name: Stop EC2 instance and wait for the instance to be stopped
-      if: always() && steps.poll_step.outputs.too_many_runs != 'true'
-      run: |
-        aws ec2 stop-instances --instance-ids $AWS_INSTANCE_ID
-        aws ec2 wait instance-stopped --instance-ids $AWS_INSTANCE_ID
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1276,7 +1276,7 @@ version = "0.1.0"
 dependencies = [
 "anyhow",
 "chrono",
- "indexmap 2.0.1",
+ "indexmap 2.9.0",
 "jsonwebtoken",
 "regex",
 "remote_storage",
@@ -1308,7 +1308,7 @@ dependencies = [
 "flate2",
 "futures",
 "http 1.1.0",
- "indexmap 2.0.1",
+ "indexmap 2.9.0",
 "itertools 0.10.5",
 "jsonwebtoken",
 "metrics",
@@ -2597,7 +2597,7 @@ dependencies = [
 "futures-sink",
 "futures-util",
 "http 0.2.9",
- "indexmap 2.0.1",
+ "indexmap 2.9.0",
 "slab",
 "tokio",
 "tokio-util",
@@ -2616,7 +2616,7 @@ dependencies = [
 "futures-sink",
 "futures-util",
 "http 1.1.0",
- "indexmap 2.0.1",
+ "indexmap 2.9.0",
 "slab",
 "tokio",
 "tokio-util",
@@ -2863,14 +2863,14 @@ dependencies = [
 "pprof",
 "regex",
 "routerify",
- "rustls 0.23.18",
+ "rustls 0.23.27",
 "rustls-pemfile 2.1.1",
 "serde",
 "serde_json",
 "serde_path_to_error",
 "thiserror 1.0.69",
 "tokio",
- "tokio-rustls 0.26.0",
+ "tokio-rustls 0.26.2",
 "tokio-stream",
 "tokio-util",
 "tracing",
@@ -3200,12 +3200,12 @@ dependencies = [

 [[package]]
 name = "indexmap"
-version = "2.0.1"
+version = "2.9.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ad227c3af19d4914570ad36d30409928b75967c298feb9ea1969db3a610bb14e"
+checksum = "cea70ddb795996207ad57735b50c5982d8844f38ba9ee5f1aedcfb708a2aa11e"
 dependencies = [
 "equivalent",
- "hashbrown 0.14.5",
+ "hashbrown 0.15.2",
 "serde",
 ]

@@ -3228,7 +3228,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "232929e1d75fe899576a3d5c7416ad0d88dbfbb3c3d6aa00873a7408a50ddb88"
 dependencies = [
 "ahash",
- "indexmap 2.0.1",
+ "indexmap 2.9.0",
 "is-terminal",
 "itoa",
 "log",
@@ -3251,7 +3251,7 @@ dependencies = [
 "crossbeam-utils",
 "dashmap 6.1.0",
 "env_logger",
- "indexmap 2.0.1",
+ "indexmap 2.9.0",
 "itoa",
 "log",
 "num-format",
@@ -3898,6 +3898,16 @@ dependencies = [
 "winapi",
 ]

+[[package]]
+name = "nu-ansi-term"
+version = "0.46.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "77a8165726e8236064dbb45459242600304b42a5ea24ee2948e18e023bf7ba84"
+dependencies = [
+ "overload",
+ "winapi",
+]
+
 [[package]]
 name = "num"
 version = "0.4.1"
@@ -4102,7 +4112,7 @@ dependencies = [
 "opentelemetry-http",
 "opentelemetry-proto",
 "opentelemetry_sdk",
- "prost 0.13.3",
+ "prost 0.13.5",
 "reqwest",
 "thiserror 1.0.69",
 ]
@@ -4115,8 +4125,8 @@ checksum = "a6e05acbfada5ec79023c85368af14abd0b307c015e9064d249b2a950ef459a6"
 dependencies = [
 "opentelemetry",
 "opentelemetry_sdk",
- "prost 0.13.3",
- "tonic",
+ "prost 0.13.5",
+ "tonic 0.12.3",
 ]

 [[package]]
@@ -4182,6 +4192,12 @@ version = "0.5.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4030760ffd992bef45b0ae3f10ce1aba99e33464c90d14dd7c039884963ddc7a"

+[[package]]
+name = "overload"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b15813163c1d831bf4a13c3610c05c0d03b39feb07f7e09fa234dac9b15aaf39"
+
 [[package]]
 name = "p256"
 version = "0.11.1"
@@ -4286,6 +4302,7 @@ dependencies = [
 "enumset",
 "fail",
 "futures",
+ "hashlink",
 "hex",
 "hex-literal",
 "http-utils",
@@ -4304,6 +4321,7 @@ dependencies = [
 "pageserver_api",
 "pageserver_client",
 "pageserver_compaction",
+ "pageserver_page_api",
 "pem",
 "pin-project-lite",
 "postgres-protocol",
@@ -4312,6 +4330,7 @@ dependencies = [
 "postgres_connection",
 "postgres_ffi",
 "postgres_initdb",
+ "posthog_client_lite",
 "pprof",
 "pq_proto",
 "procfs",
@@ -4322,7 +4341,7 @@ dependencies = [
 "reqwest",
 "rpds",
 "rstest",
- "rustls 0.23.18",
+ "rustls 0.23.27",
 "scopeguard",
 "send-future",
 "serde",
@@ -4341,11 +4360,13 @@ dependencies = [
 "tokio-epoll-uring",
 "tokio-io-timeout",
 "tokio-postgres",
- "tokio-rustls 0.26.0",
+ "tokio-rustls 0.26.2",
 "tokio-stream",
 "tokio-tar",
 "tokio-util",
 "toml_edit",
+ "tonic 0.13.1",
+ "tonic-reflection",
 "tracing",
 "tracing-utils",
 "twox-hash",
@@ -4434,6 +4455,22 @@ dependencies = [
 "workspace_hack",
 ]

+[[package]]
+name = "pageserver_page_api"
+version = "0.1.0"
+dependencies = [
+ "bytes",
+ "pageserver_api",
+ "postgres_ffi",
+ "prost 0.13.5",
+ "smallvec",
+ "thiserror 1.0.69",
+ "tonic 0.13.1",
+ "tonic-build",
+ "utils",
+ "workspace_hack",
+]
+
 [[package]]
 name = "papaya"
 version = "0.2.1"
@@ -4810,14 +4847,14 @@ dependencies = [
 "bytes",
 "once_cell",
 "pq_proto",
- "rustls 0.23.18",
+ "rustls 0.23.27",
 "rustls-pemfile 2.1.1",
 "serde",
 "thiserror 1.0.69",
 "tokio",
 "tokio-postgres",
 "tokio-postgres-rustls",
- "tokio-rustls 0.26.0",
+ "tokio-rustls 0.26.2",
 "tokio-util",
 "tracing",
 ]
@@ -4871,11 +4908,16 @@ name = "posthog_client_lite"
 version = "0.1.0"
 dependencies = [
 "anyhow",
+ "arc-swap",
 "reqwest",
 "serde",
 "serde_json",
 "sha2",
 "thiserror 1.0.69",
+ "tokio",
+ "tokio-util",
+ "tracing",
+ "tracing-utils",
 "workspace_hack",
 ]

@@ -4924,7 +4966,7 @@ dependencies = [
 "inferno 0.12.0",
 "num",
 "paste",
- "prost 0.13.3",
+ "prost 0.13.5",
 ]

 [[package]]
@@ -5029,12 +5071,12 @@ dependencies = [

 [[package]]
 name = "prost"
-version = "0.13.3"
+version = "0.13.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7b0487d90e047de87f984913713b85c601c05609aad5b0df4b4573fbf69aa13f"
+checksum = "2796faa41db3ec313a31f7624d9286acf277b52de526150b7e69f3debf891ee5"
 dependencies = [
 "bytes",
- "prost-derive 0.13.3",
+ "prost-derive 0.13.5",
 ]

 [[package]]
@@ -5072,7 +5114,7 @@ dependencies = [
 "once_cell",
 "petgraph",
 "prettyplease",
- "prost 0.13.3",
+ "prost 0.13.5",
 "prost-types 0.13.3",
 "regex",
 "syn 2.0.100",
@@ -5094,9 +5136,9 @@ dependencies = [

 [[package]]
 name = "prost-derive"
-version = "0.13.3"
+version = "0.13.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e9552f850d5f0964a4e4d0bf306459ac29323ddfbae05e35a7c0d35cb0803cc5"
+checksum = "8a56d757972c98b346a9b766e3f02746cde6dd1cd1d1d563472929fdd74bec4d"
 dependencies = [
 "anyhow",
 "itertools 0.12.1",
@@ -5120,7 +5162,7 @@ version = "0.13.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4759aa0d3a6232fb8dbdb97b61de2c20047c68aca932c7ed76da9d788508d670"
 dependencies = [
- "prost 0.13.3",
+ "prost 0.13.5",
 ]

 [[package]]
@@ -5168,7 +5210,7 @@ dependencies = [
 "hyper 0.14.30",
 "hyper 1.4.1",
 "hyper-util",
- "indexmap 2.0.1",
+ "indexmap 2.9.0",
 "ipnet",
 "itertools 0.10.5",
 "itoa",
@@ -5202,10 +5244,9 @@ dependencies = [
 "rsa",
 "rstest",
 "rustc-hash 1.1.0",
- "rustls 0.23.18",
+ "rustls 0.23.27",
 "rustls-native-certs 0.8.0",
 "rustls-pemfile 2.1.1",
- "ryu",
 "scopeguard",
 "serde",
 "serde_json",
@@ -5222,13 +5263,14 @@ dependencies = [
 "tokio",
 "tokio-postgres",
 "tokio-postgres2",
- "tokio-rustls 0.26.0",
+ "tokio-rustls 0.26.2",
 "tokio-tungstenite 0.21.0",
 "tokio-util",
 "tracing",
 "tracing-log",
 "tracing-opentelemetry",
 "tracing-subscriber",
+ "tracing-test",
 "tracing-utils",
 "try-lock",
 "typed-json",
@@ -5445,13 +5487,13 @@ dependencies = [
 "num-bigint",
 "percent-encoding",
 "pin-project-lite",
- "rustls 0.23.18",
+ "rustls 0.23.27",
 "rustls-native-certs 0.8.0",
 "ryu",
 "sha1_smol",
 "socket2",
 "tokio",
- "tokio-rustls 0.26.0",
+ "tokio-rustls 0.26.2",
 "tokio-util",
 "url",
 ]
@@ -5899,15 +5941,15 @@ dependencies = [

 [[package]]
 name = "rustls"
-version = "0.23.18"
+version = "0.23.27"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9c9cc1d47e243d655ace55ed38201c19ae02c148ae56412ab8750e8f0166ab7f"
+checksum = "730944ca083c1c233a75c09f199e973ca499344a2b7ba9e755c457e86fb4a321"
 dependencies = [
 "log",
 "once_cell",
 "ring",
 "rustls-pki-types",
- "rustls-webpki 0.102.8",
+ "rustls-webpki 0.103.3",
 "subtle",
 "zeroize",
 ]
@@ -5996,6 +6038,17 @@ dependencies = [
 "untrusted",
 ]

+[[package]]
+name = "rustls-webpki"
+version = "0.103.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e4a72fe2bcf7a6ac6fd7d0b9e5cb68aeb7d4c0a0271730218b3e92d43b4eb435"
+dependencies = [
+ "ring",
+ "rustls-pki-types",
+ "untrusted",
+]
+
 [[package]]
 name = "rustversion"
 version = "1.0.12"
@@ -6047,7 +6100,7 @@ dependencies = [
 "regex",
 "remote_storage",
 "reqwest",
- "rustls 0.23.18",
+ "rustls 0.23.27",
 "safekeeper_api",
 "safekeeper_client",
 "scopeguard",
@@ -6064,7 +6117,7 @@ dependencies = [
 "tokio",
 "tokio-io-timeout",
 "tokio-postgres",
- "tokio-rustls 0.26.0",
+ "tokio-rustls 0.26.2",
 "tokio-stream",
 "tokio-tar",
 "tokio-util",
@@ -6236,7 +6289,7 @@ checksum = "255914a8e53822abd946e2ce8baa41d4cded6b8e938913b7f7b9da5b7ab44335"
 dependencies = [
 "httpdate",
 "reqwest",
- "rustls 0.23.18",
+ "rustls 0.23.27",
 "sentry-backtrace",
 "sentry-contexts",
 "sentry-core",
@@ -6665,11 +6718,11 @@ dependencies = [
 "metrics",
 "once_cell",
 "parking_lot 0.12.1",
- "prost 0.13.3",
- "rustls 0.23.18",
+ "prost 0.13.5",
+ "rustls 0.23.27",
 "tokio",
- "tokio-rustls 0.26.0",
- "tonic",
+ "tokio-rustls 0.26.2",
+ "tonic 0.13.1",
 "tonic-build",
 "tracing",
 "utils",
@@ -6711,7 +6764,7 @@ dependencies = [
 "regex",
 "reqwest",
 "routerify",
- "rustls 0.23.18",
+ "rustls 0.23.27",
 "rustls-native-certs 0.8.0",
 "safekeeper_api",
 "safekeeper_client",
@@ -6726,7 +6779,7 @@ dependencies = [
 "tokio",
 "tokio-postgres",
 "tokio-postgres-rustls",
- "tokio-rustls 0.26.0",
+ "tokio-rustls 0.26.2",
 "tokio-util",
 "tracing",
 "utils",
@@ -6764,7 +6817,7 @@ dependencies = [
 "postgres_ffi",
 "remote_storage",
 "reqwest",
- "rustls 0.23.18",
+ "rustls 0.23.27",
 "rustls-native-certs 0.8.0",
 "serde",
 "serde_json",
@@ -7298,10 +7351,10 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "04fb792ccd6bbcd4bba408eb8a292f70fc4a3589e5d793626f45190e6454b6ab"
 dependencies = [
 "ring",
- "rustls 0.23.18",
+ "rustls 0.23.27",
 "tokio",
 "tokio-postgres",
- "tokio-rustls 0.26.0",
+ "tokio-rustls 0.26.2",
 "x509-certificate",
 ]

@@ -7345,12 +7398,11 @@ dependencies = [

 [[package]]
 name = "tokio-rustls"
-version = "0.26.0"
+version = "0.26.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0c7bc40d0e5a97695bb96e27995cd3a08538541b0a846f65bba7a359f36700d4"
+checksum = "8e727b36a1a0e8b74c376ac2211e40c2c8af09fb4013c60d910495810f008e9b"
 dependencies = [
- "rustls 0.23.18",
- "rustls-pki-types",
+ "rustls 0.23.27",
 "tokio",
 ]

@@ -7448,7 +7500,7 @@ version = "0.22.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f21c7aaf97f1bd9ca9d4f9e73b0a6c74bd5afef56f2bc931943a6e1c37e04e38"
 dependencies = [
- "indexmap 2.0.1",
+ "indexmap 2.9.0",
 "serde",
 "serde_spanned",
 "toml_datetime",
@@ -7467,18 +7519,41 @@ dependencies = [
 "http 1.1.0",
 "http-body 1.0.0",
 "http-body-util",
+ "percent-encoding",
+ "pin-project",
+ "prost 0.13.5",
+ "tokio-stream",
+ "tower-layer",
+ "tower-service",
+ "tracing",
+]
+
+[[package]]
+name = "tonic"
+version = "0.13.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7e581ba15a835f4d9ea06c55ab1bd4dce26fc53752c69a04aac00703bfb49ba9"
+dependencies = [
+ "async-trait",
+ "axum",
+ "base64 0.22.1",
+ "bytes",
+ "h2 0.4.4",
+ "http 1.1.0",
+ "http-body 1.0.0",
+ "http-body-util",
 "hyper 1.4.1",
 "hyper-timeout",
 "hyper-util",
 "percent-encoding",
 "pin-project",
- "prost 0.13.3",
+ "prost 0.13.5",
 "rustls-native-certs 0.8.0",
- "rustls-pemfile 2.1.1",
+ "socket2",
 "tokio",
- "tokio-rustls 0.26.0",
+ "tokio-rustls 0.26.2",
 "tokio-stream",
- "tower 0.4.13",
+ "tower 0.5.2",
 "tower-layer",
 "tower-service",
 "tracing",
@@ -7486,9 +7561,9 @@ dependencies = [

 [[package]]
 name = "tonic-build"
-version = "0.12.3"
+version = "0.13.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9557ce109ea773b399c9b9e5dca39294110b74f1f342cb347a80d1fce8c26a11"
+checksum = "eac6f67be712d12f0b41328db3137e0d0757645d8904b4cb7d51cd9c2279e847"
 dependencies = [
 "prettyplease",
 "proc-macro2",
@@ -7498,6 +7573,19 @@ dependencies = [
 "syn 2.0.100",
 ]

+[[package]]
+name = "tonic-reflection"
+version = "0.13.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f9687bd5bfeafebdded2356950f278bba8226f0b32109537c4253406e09aafe1"
+dependencies = [
+ "prost 0.13.5",
+ "prost-types 0.13.3",
+ "tokio",
+ "tokio-stream",
+ "tonic 0.13.1",
+]
+
 [[package]]
 name = "tower"
 version = "0.4.13"
@@ -7506,16 +7594,11 @@ checksum = "b8fa9be0de6cf49e536ce1851f987bd21a43b771b09473c3549a6c853db37c1c"
 dependencies = [
 "futures-core",
 "futures-util",
- "indexmap 1.9.3",
 "pin-project",
 "pin-project-lite",
- "rand 0.8.5",
- "slab",
 "tokio",
- "tokio-util",
 "tower-layer",
 "tower-service",
- "tracing",
 ]

 [[package]]
@@ -7526,9 +7609,12 @@ checksum = "d039ad9159c98b70ecfd540b2573b97f7f52c3e8d9f8ad57a24b916a536975f9"
 dependencies = [
 "futures-core",
 "futures-util",
+ "indexmap 2.9.0",
 "pin-project-lite",
+ "slab",
 "sync_wrapper 1.0.1",
 "tokio",
+ "tokio-util",
 "tower-layer",
 "tower-service",
 "tracing",
@@ -7679,6 +7765,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e8189decb5ac0fa7bc8b96b7cb9b2701d60d48805aca84a238004d665fcc4008"
 dependencies = [
 "matchers",
+ "nu-ansi-term",
 "once_cell",
 "regex",
 "serde",
@@ -7692,6 +7779,27 @@ dependencies = [
 "tracing-serde",
 ]

+[[package]]
+name = "tracing-test"
+version = "0.2.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "557b891436fe0d5e0e363427fc7f217abf9ccd510d5136549847bdcbcd011d68"
+dependencies = [
+ "tracing-core",
+ "tracing-subscriber",
+ "tracing-test-macro",
+]
+
+[[package]]
+name = "tracing-test-macro"
+version = "0.2.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "04659ddb06c87d233c566112c1c9c5b9e98256d9af50ec3bc9c8327f873a7568"
+dependencies = [
+ "quote",
+ "syn 2.0.100",
+]
+
 [[package]]
 name = "tracing-utils"
 version = "0.1.0"
@@ -7834,7 +7942,7 @@ dependencies = [
 "base64 0.22.1",
 "log",
 "once_cell",
- "rustls 0.23.18",
+ "rustls 0.23.27",
 "rustls-pki-types",
 "url",
 "webpki-roots",
@@ -8029,7 +8137,7 @@ dependencies = [
 "pageserver_api",
 "postgres_ffi",
 "pprof",
- "prost 0.13.3",
+ "prost 0.13.5",
 "remote_storage",
 "serde",
 "serde_json",
@@ -8449,6 +8557,8 @@ dependencies = [
 "ahash",
 "anstream",
 "anyhow",
+ "axum",
+ "axum-core",
 "base64 0.13.1",
 "base64 0.21.7",
 "base64ct",
@@ -8471,10 +8581,8 @@ dependencies = [
 "fail",
 "form_urlencoded",
 "futures-channel",
- "futures-core",
 "futures-executor",
 "futures-io",
- "futures-task",
 "futures-util",
 "generic-array",
 "getrandom 0.2.11",
@@ -8485,8 +8593,7 @@ dependencies = [
 "hyper 0.14.30",
 "hyper 1.4.1",
 "hyper-util",
- "indexmap 1.9.3",
- "indexmap 2.0.1",
+ "indexmap 2.9.0",
 "itertools 0.12.1",
 "lazy_static",
 "libc",
@@ -8505,19 +8612,18 @@ dependencies = [
 "once_cell",
 "p256 0.13.2",
 "parquet",
- "percent-encoding",
 "prettyplease",
 "proc-macro2",
- "prost 0.13.3",
+ "prost 0.13.5",
 "quote",
 "rand 0.8.5",
 "regex",
 "regex-automata 0.4.3",
 "regex-syntax 0.8.2",
 "reqwest",
- "rustls 0.23.18",
+ "rustls 0.23.27",
 "rustls-pki-types",
- "rustls-webpki 0.102.8",
+ "rustls-webpki 0.103.3",
 "scopeguard",
 "sec1 0.7.3",
 "serde",
@@ -8535,15 +8641,15 @@ dependencies = [
 "time",
 "time-macros",
 "tokio",
- "tokio-rustls 0.26.0",
+ "tokio-rustls 0.26.2",
 "tokio-stream",
 "tokio-util",
 "toml_edit",
- "tonic",
- "tower 0.4.13",
+ "tower 0.5.2",
 "tracing",
 "tracing-core",
 "tracing-log",
+ "tracing-subscriber",
 "url",
 "uuid",
 "zeroize",
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -9,6 +9,7 @@ members = [
    "pageserver/ctl",
    "pageserver/client",
    "pageserver/pagebench",
+    "pageserver/page_api",
    "proxy",
    "safekeeper",
    "safekeeper/client",
@@ -148,7 +149,7 @@ 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"
+prost = "0.13.5"
 rand = "0.8"
 redis = { version = "0.29.2", features = ["tokio-rustls-comp", "keep-alive"] }
 regex = "1.10.2"
@@ -198,7 +199,8 @@ tokio-tar = "0.3"
 tokio-util = { version = "0.7.10", features = ["io", "rt"] }
 toml = "0.8"
 toml_edit = "0.22"
-tonic = {version = "0.12.3", default-features = false, features = ["channel", "tls", "tls-roots"]}
+tonic = { version = "0.13.1", default-features = false, features = ["channel", "codegen", "prost", "router", "server", "tls-ring", "tls-native-roots"] }
+tonic-reflection = { version = "0.13.1", features = ["server"] }
 tower = { version = "0.5.2", default-features = false }
 tower-http = { version = "0.6.2", features = ["auth", "request-id", "trace"] }

@@ -245,6 +247,7 @@ azure_storage_blobs = { git = "https://github.com/neondatabase/azure-sdk-for-rus
 ## Local libraries
 compute_api = { version = "0.1", path = "./libs/compute_api/" }
 consumption_metrics = { version = "0.1", path = "./libs/consumption_metrics/" }
+desim = { version = "0.1", path = "./libs/desim" }
 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/" }
@@ -252,23 +255,24 @@ pageserver = { path = "./pageserver" }
 pageserver_api = { version = "0.1", path = "./libs/pageserver_api/" }
 pageserver_client = { path = "./pageserver/client" }
 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_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/" }
 remote_storage = { version = "0.1", path = "./libs/remote_storage/" }
 safekeeper_api = { version = "0.1", path = "./libs/safekeeper_api" }
 safekeeper_client = { path = "./safekeeper/client" }
-desim = { version = "0.1", path = "./libs/desim" }
 storage_broker = { version = "0.1", path = "./storage_broker/" } # Note: main broker code is inside the binary crate, so linking with the library shouldn't be heavy.
 storage_controller_client = { path = "./storage_controller/client" }
 tenant_size_model = { version = "0.1", path = "./libs/tenant_size_model/" }
 tracing-utils = { version = "0.1", path = "./libs/tracing-utils/" }
 utils = { version = "0.1", path = "./libs/utils/" }
 vm_monitor = { version = "0.1", path = "./libs/vm_monitor/" }
-walproposer = { version = "0.1", path = "./libs/walproposer/" }
 wal_decoder = { version = "0.1", path = "./libs/wal_decoder" }
+walproposer = { version = "0.1", path = "./libs/walproposer/" }

 ## Common library dependency
 workspace_hack = { version = "0.1", path = "./workspace_hack/" }
@@ -278,7 +282,7 @@ criterion = "0.5.1"
 rcgen = "0.13"
 rstest = "0.18"
 camino-tempfile = "1.0.2"
-tonic-build = "0.12"
+tonic-build = "0.13.1"

 [patch.crates-io]

--- a/build-tools.Dockerfile
+++ b/build-tools.Dockerfile
@@ -155,7 +155,7 @@ RUN set -e \

 # Keep the version the same as in compute/compute-node.Dockerfile and
 # test_runner/regress/test_compute_metrics.py.
-ENV SQL_EXPORTER_VERSION=0.17.0
+ENV SQL_EXPORTER_VERSION=0.17.3
 RUN curl -fsSL \
    "https://github.com/burningalchemist/sql_exporter/releases/download/${SQL_EXPORTER_VERSION}/sql_exporter-${SQL_EXPORTER_VERSION}.linux-$(case "$(uname -m)" in x86_64) echo amd64;; aarch64) echo arm64;; esac).tar.gz" \
    --output sql_exporter.tar.gz \
@@ -310,13 +310,13 @@ RUN curl -sSO https://static.rust-lang.org/rustup/dist/$(uname -m)-unknown-linux
    . "$HOME/.cargo/env" && \
    cargo --version && rustup --version && \
    rustup component add llvm-tools rustfmt clippy && \
-    cargo install rustfilt            --version ${RUSTFILT_VERSION} && \
-    cargo install cargo-hakari        --version ${CARGO_HAKARI_VERSION} && \
-    cargo install cargo-deny --locked --version ${CARGO_DENY_VERSION} && \
-    cargo install cargo-hack          --version ${CARGO_HACK_VERSION} && \
-    cargo install cargo-nextest       --version ${CARGO_NEXTEST_VERSION} && \
-    cargo install cargo-chef --locked --version ${CARGO_CHEF_VERSION} && \
-    cargo install diesel_cli          --version ${CARGO_DIESEL_CLI_VERSION} \
+    cargo install rustfilt            --version ${RUSTFILT_VERSION} --locked && \
+    cargo install cargo-hakari        --version ${CARGO_HAKARI_VERSION} --locked && \
+    cargo install cargo-deny          --version ${CARGO_DENY_VERSION} --locked && \
+    cargo install cargo-hack          --version ${CARGO_HACK_VERSION} --locked && \
+    cargo install cargo-nextest       --version ${CARGO_NEXTEST_VERSION} --locked && \
+    cargo install cargo-chef          --version ${CARGO_CHEF_VERSION} --locked && \
+    cargo install diesel_cli          --version ${CARGO_DIESEL_CLI_VERSION} --locked \
                                      --features postgres-bundled --no-default-features && \
    rm -rf /home/nonroot/.cargo/registry && \
    rm -rf /home/nonroot/.cargo/git
--- a/compute/compute-node.Dockerfile
+++ b/compute/compute-node.Dockerfile
@@ -582,6 +582,38 @@ RUN make -j $(getconf _NPROCESSORS_ONLN) && \
    make -j $(getconf _NPROCESSORS_ONLN) install && \
    echo 'trusted = true' >> /usr/local/pgsql/share/extension/hypopg.control

+#########################################################################################
+#
+# Layer "online_advisor-build"
+# compile online_advisor extension
+#
+#########################################################################################
+FROM build-deps AS online_advisor-src
+ARG PG_VERSION
+
+# online_advisor supports all Postgres version starting from PG14, but prior to PG17 has to be included in preload_shared_libraries
+# last release 1.0 - May 15, 2025
+WORKDIR /ext-src
+RUN case "${PG_VERSION:?}" in \
+    "v17") \
+        ;; \
+    *) \
+        echo "skipping the version of online_advistor for $PG_VERSION" && exit 0 \
+        ;; \
+    esac && \
+	wget https://github.com/knizhnik/online_advisor/archive/refs/tags/1.0.tar.gz -O online_advisor.tar.gz && \
+    echo "059b7d9e5a90013a58bdd22e9505b88406ce05790675eb2d8434e5b215652d54 online_advisor.tar.gz" | sha256sum --check && \
+    mkdir online_advisor-src && cd online_advisor-src && tar xzf ../online_advisor.tar.gz --strip-components=1 -C .
+
+FROM pg-build AS online_advisor-build
+COPY --from=online_advisor-src /ext-src/ /ext-src/
+WORKDIR /ext-src/
+RUN if [ -d online_advisor-src ]; then \
+	    cd online_advisor-src && \
+        make -j install && \
+        echo 'trusted = true' >> /usr/local/pgsql/share/extension/online_advisor.control; \
+    fi
+
 #########################################################################################
 #
 # Layer "pg_hashids-build"
@@ -1648,6 +1680,7 @@ COPY --from=pg_jsonschema-build /usr/local/pgsql/ /usr/local/pgsql/
 COPY --from=pg_graphql-build /usr/local/pgsql/ /usr/local/pgsql/
 COPY --from=pg_tiktoken-build /usr/local/pgsql/ /usr/local/pgsql/
 COPY --from=hypopg-build /usr/local/pgsql/ /usr/local/pgsql/
+COPY --from=online_advisor-build /usr/local/pgsql/ /usr/local/pgsql/
 COPY --from=pg_hashids-build /usr/local/pgsql/ /usr/local/pgsql/
 COPY --from=rum-build /usr/local/pgsql/ /usr/local/pgsql/
 COPY --from=pgtap-build /usr/local/pgsql/ /usr/local/pgsql/
@@ -1751,17 +1784,17 @@ ARG TARGETARCH
 RUN if [ "$TARGETARCH" = "amd64" ]; then\
        postgres_exporter_sha256='59aa4a7bb0f7d361f5e05732f5ed8c03cc08f78449cef5856eadec33a627694b';\
        pgbouncer_exporter_sha256='c9f7cf8dcff44f0472057e9bf52613d93f3ffbc381ad7547a959daa63c5e84ac';\
-        sql_exporter_sha256='38e439732bbf6e28ca4a94d7bc3686d3fa1abdb0050773d5617a9efdb9e64d08';\
+        sql_exporter_sha256='9a41127a493e8bfebfe692bf78c7ed2872a58a3f961ee534d1b0da9ae584aaab';\
    else\
        postgres_exporter_sha256='d1dedea97f56c6d965837bfd1fbb3e35a3b4a4556f8cccee8bd513d8ee086124';\
        pgbouncer_exporter_sha256='217c4afd7e6492ae904055bc14fe603552cf9bac458c063407e991d68c519da3';\
-        sql_exporter_sha256='11918b00be6e2c3a67564adfdb2414fdcbb15a5db76ea17d1d1a944237a893c6';\
+        sql_exporter_sha256='530e6afc77c043497ed965532c4c9dfa873bc2a4f0b3047fad367715c0081d6a';\
    fi\
    && curl -sL https://github.com/prometheus-community/postgres_exporter/releases/download/v0.17.1/postgres_exporter-0.17.1.linux-${TARGETARCH}.tar.gz\
     | tar xzf - --strip-components=1 -C.\
    && curl -sL https://github.com/prometheus-community/pgbouncer_exporter/releases/download/v0.10.2/pgbouncer_exporter-0.10.2.linux-${TARGETARCH}.tar.gz\
     | tar xzf - --strip-components=1 -C.\
-    && curl -sL https://github.com/burningalchemist/sql_exporter/releases/download/0.17.0/sql_exporter-0.17.0.linux-${TARGETARCH}.tar.gz\
+    && curl -sL https://github.com/burningalchemist/sql_exporter/releases/download/0.17.3/sql_exporter-0.17.3.linux-${TARGETARCH}.tar.gz\
     | tar xzf - --strip-components=1 -C.\
    && echo "${postgres_exporter_sha256} postgres_exporter" | sha256sum -c -\
    && echo "${pgbouncer_exporter_sha256} pgbouncer_exporter" | sha256sum -c -\
@@ -1814,7 +1847,7 @@ COPY docker-compose/ext-src/ /ext-src/
 COPY --from=pg-build /postgres /postgres
 #COPY --from=postgis-src /ext-src/ /ext-src/
 COPY --from=plv8-src /ext-src/ /ext-src/
-#COPY --from=h3-pg-src /ext-src/ /ext-src/
+COPY --from=h3-pg-src /ext-src/h3-pg-src /ext-src/h3-pg-src
 COPY --from=postgresql-unit-src /ext-src/ /ext-src/
 COPY --from=pgvector-src /ext-src/ /ext-src/
 COPY --from=pgjwt-src /ext-src/ /ext-src/
@@ -1823,6 +1856,7 @@ COPY --from=pgjwt-src /ext-src/ /ext-src/
 COPY --from=pg_graphql-src /ext-src/ /ext-src/
 #COPY --from=pg_tiktoken-src /ext-src/ /ext-src/
 COPY --from=hypopg-src /ext-src/ /ext-src/
+COPY --from=online_advisor-src /ext-src/ /ext-src/
 COPY --from=pg_hashids-src /ext-src/ /ext-src/
 COPY --from=rum-src /ext-src/ /ext-src/
 COPY --from=pgtap-src /ext-src/ /ext-src/
--- a/compute/patches/rum.patch
+++ b/compute/patches/rum.patch
@@ -7,7 +7,7 @@ index 255e616..1c6edb7 100644
 			 RelationGetRelationName(index));
 
 +#ifdef NEON_SMGR
-+	smgr_start_unlogged_build(index->rd_smgr);
+	smgr_start_unlogged_build(RelationGetSmgr(index));
 +#endif
 +
 	initRumState(&buildstate.rumstate, index);
@@ -18,7 +18,7 @@ index 255e616..1c6edb7 100644
 	rumUpdateStats(index, &buildstate.buildStats, buildstate.rumstate.isBuild);
 
 +#ifdef NEON_SMGR
-+	smgr_finish_unlogged_build_phase_1(index->rd_smgr);
+	smgr_finish_unlogged_build_phase_1(RelationGetSmgr(index));
 +#endif
 +
 	/*
@@ -29,7 +29,7 @@ index 255e616..1c6edb7 100644
 	}
 
 +#ifdef NEON_SMGR
-+	smgr_end_unlogged_build(index->rd_smgr);
+	smgr_end_unlogged_build(RelationGetSmgr(index));
 +#endif
 +
 	/*
--- a/compute_tools/src/bin/compute_ctl.rs
+++ b/compute_tools/src/bin/compute_ctl.rs
@@ -57,21 +57,6 @@ use tracing::{error, info};
 use url::Url;
 use utils::failpoint_support;

-// Compatibility hack: if the control plane specified any remote-ext-config
-// use the default value for extension storage proxy gateway.
-// Remove this once the control plane is updated to pass the gateway URL
-fn parse_remote_ext_base_url(arg: &str) -> Result<String> {
-    const FALLBACK_PG_EXT_GATEWAY_BASE_URL: &str =
-        "http://pg-ext-s3-gateway.pg-ext-s3-gateway.svc.cluster.local";
-
-    Ok(if arg.starts_with("http") {
-        arg
-    } else {
-        FALLBACK_PG_EXT_GATEWAY_BASE_URL
-    }
-    .to_owned())
-}
-
 #[derive(Parser)]
 #[command(rename_all = "kebab-case")]
 struct Cli {
@@ -79,9 +64,8 @@ struct Cli {
    pub pgbin: String,

    /// The base URL for the remote extension storage proxy gateway.
-    /// Should be in the form of `http(s)://<gateway-hostname>[:<port>]`.
-    #[arg(short = 'r', long, value_parser = parse_remote_ext_base_url, alias = "remote-ext-config")]
-    pub remote_ext_base_url: Option<String>,
+    #[arg(short = 'r', long)]
+    pub remote_ext_base_url: Option<Url>,

    /// The port to bind the external listening HTTP server to. Clients running
    /// outside the compute will talk to the compute through this port. Keep
@@ -136,6 +120,10 @@ struct Cli {
        requires = "compute-id"
    )]
    pub control_plane_uri: Option<String>,
+
+    /// Interval in seconds for collecting installed extensions statistics
+    #[arg(long, default_value = "3600")]
+    pub installed_extensions_collection_interval: u64,
 }

 fn main() -> Result<()> {
@@ -179,6 +167,7 @@ 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,
        },
        config,
    )?;
@@ -271,18 +260,4 @@ mod test {
    fn verify_cli() {
        Cli::command().debug_assert()
    }
-
-    #[test]
-    fn parse_pg_ext_gateway_base_url() {
-        let arg = "http://pg-ext-s3-gateway2";
-        let result = super::parse_remote_ext_base_url(arg).unwrap();
-        assert_eq!(result, arg);
-
-        let arg = "pg-ext-s3-gateway";
-        let result = super::parse_remote_ext_base_url(arg).unwrap();
-        assert_eq!(
-            result,
-            "http://pg-ext-s3-gateway.pg-ext-s3-gateway.svc.cluster.local"
-        );
-    }
 }
--- a/compute_tools/src/bin/fast_import.rs
+++ b/compute_tools/src/bin/fast_import.rs
@@ -339,6 +339,8 @@ async fn run_dump_restore(
    destination_connstring: String,
 ) -> Result<(), anyhow::Error> {
    let dumpdir = workdir.join("dumpdir");
+    let num_jobs = num_cpus::get().to_string();
+    info!("using {num_jobs} jobs for dump/restore");

    let common_args = [
        // schema mapping (prob suffices to specify them on one side)
@@ -354,7 +356,7 @@ async fn run_dump_restore(
        "directory".to_string(),
        // concurrency
        "--jobs".to_string(),
-        num_cpus::get().to_string(),
+        num_jobs,
        // progress updates
        "--verbose".to_string(),
    ];
--- a/compute_tools/src/compute.rs
+++ b/compute_tools/src/compute.rs
@@ -31,6 +31,7 @@ use std::time::{Duration, Instant};
 use std::{env, fs};
 use tokio::spawn;
 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;
@@ -96,7 +97,10 @@ pub struct ComputeNodeParams {
    pub internal_http_port: u16,

    /// the address of extension storage proxy gateway
-    pub remote_ext_base_url: Option<String>,
+    pub remote_ext_base_url: Option<Url>,
+
+    /// Interval for installed extensions collection
+    pub installed_extensions_collection_interval: u64,
 }

 /// Compute node info shared across several `compute_ctl` threads.
@@ -695,25 +699,18 @@ impl ComputeNode {
                let log_directory_path = Path::new(&self.params.pgdata).join("log");
                let log_directory_path = log_directory_path.to_string_lossy().to_string();

-                // Add project_id,endpoint_id tag to identify the logs.
+                // Add project_id,endpoint_id to identify the logs.
                //
                // These ids are passed from cplane,
-                // for backwards compatibility (old computes that don't have them),
-                // we set them to None.
-                // TODO: Clean up this code when all computes have them.
-                let tag: Option<String> = match (
-                    pspec.spec.project_id.as_deref(),
-                    pspec.spec.endpoint_id.as_deref(),
-                ) {
-                    (Some(project_id), Some(endpoint_id)) => {
-                        Some(format!("{project_id}/{endpoint_id}"))
-                    }
-                    (Some(project_id), None) => Some(format!("{project_id}/None")),
-                    (None, Some(endpoint_id)) => Some(format!("None,{endpoint_id}")),
-                    (None, None) => None,
-                };
+                let endpoint_id = pspec.spec.endpoint_id.as_deref().unwrap_or("");
+                let project_id = pspec.spec.project_id.as_deref().unwrap_or("");

-                configure_audit_rsyslog(log_directory_path.clone(), tag, &remote_endpoint)?;
+                configure_audit_rsyslog(
+                    log_directory_path.clone(),
+                    endpoint_id,
+                    project_id,
+                    &remote_endpoint,
+                )?;

                // Launch a background task to clean up the audit logs
                launch_pgaudit_gc(log_directory_path);
@@ -749,17 +746,7 @@ impl ComputeNode {

            let conf = self.get_tokio_conn_conf(None);
            tokio::task::spawn(async {
-                let res = get_installed_extensions(conf).await;
-                match res {
-                    Ok(extensions) => {
-                        info!(
-                            "[NEON_EXT_STAT] {}",
-                            serde_json::to_string(&extensions)
-                                .expect("failed to serialize extensions list")
-                        );
-                    }
-                    Err(err) => error!("could not get installed extensions: {err:?}"),
-                }
+                let _ = installed_extensions(conf).await;
            });
        }

@@ -789,6 +776,9 @@ impl ComputeNode {
        // Log metrics so that we can search for slow operations in logs
        info!(?metrics, postmaster_pid = %postmaster_pid, "compute start finished");

+        // Spawn the extension stats background task
+        self.spawn_extension_stats_task();
+
        if pspec.spec.prewarm_lfc_on_startup {
            self.prewarm_lfc();
        }
@@ -2199,6 +2189,41 @@ LIMIT 100",
            info!("Pageserver config changed");
        }
    }
+
+    pub fn spawn_extension_stats_task(&self) {
+        let conf = self.tokio_conn_conf.clone();
+        let installed_extensions_collection_interval =
+            self.params.installed_extensions_collection_interval;
+        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(
+                installed_extensions_collection_interval,
+            ))
+            .await;
+            let mut interval = tokio::time::interval(tokio::time::Duration::from_secs(
+                installed_extensions_collection_interval,
+            ));
+            loop {
+                interval.tick().await;
+                let _ = installed_extensions(conf.clone()).await;
+            }
+        });
+    }
+}
+
+pub async fn installed_extensions(conf: tokio_postgres::Config) -> Result<()> {
+    let res = get_installed_extensions(conf).await;
+    match res {
+        Ok(extensions) => {
+            info!(
+                "[NEON_EXT_STAT] {}",
+                serde_json::to_string(&extensions).expect("failed to serialize extensions list")
+            );
+        }
+        Err(err) => error!("could not get installed extensions: {err:?}"),
+    }
+    Ok(())
 }

 pub fn forward_termination_signal() {
--- a/compute_tools/src/config_template/compute_audit_rsyslog_template.conf
+++ b/compute_tools/src/config_template/compute_audit_rsyslog_template.conf
@@ -2,10 +2,24 @@
 module(load="imfile")

 # Input configuration for log files in the specified directory
-# Replace {log_directory} with the directory containing the log files
-input(type="imfile" File="{log_directory}/*.log" Tag="{tag}" Severity="info" Facility="local0")
+# The messages can be multiline. The start of the message is a timestamp
+# in "%Y-%m-%d %H:%M:%S.%3N GMT" (so timezone hardcoded).
+# Replace log_directory with the directory containing the log files
+input(type="imfile" File="{log_directory}/*.log"
+  Tag="pgaudit_log" Severity="info" Facility="local5"
+  startmsg.regex="^[[:digit:]]{{4}}-[[:digit:]]{{2}}-[[:digit:]]{{2}} [[:digit:]]{{2}}:[[:digit:]]{{2}}:[[:digit:]]{{2}}.[[:digit:]]{{3}} GMT,")
+
 # the directory to store rsyslog state files
 global(workDirectory="/var/log/rsyslog")

-# Forward logs to remote syslog server
-*.* @@{remote_endpoint}
+# Construct json, endpoint_id and project_id as additional metadata
+set $.json_log!endpoint_id = "{endpoint_id}";
+set $.json_log!project_id = "{project_id}";
+set $.json_log!msg = $msg;
+
+# Template suitable for rfc5424 syslog format
+template(name="PgAuditLog" type="string"
+    string="<%PRI%>1 %TIMESTAMP:::date-rfc3339% %HOSTNAME% - - - - %$.json_log%")
+
+# Forward to remote syslog receiver (@@<hostname>:<port>;format
+local5.info @@{remote_endpoint};PgAuditLog
--- a/compute_tools/src/extension_server.rs
+++ b/compute_tools/src/extension_server.rs
@@ -83,6 +83,7 @@ use reqwest::StatusCode;
 use tar::Archive;
 use tracing::info;
 use tracing::log::warn;
+use url::Url;
 use zstd::stream::read::Decoder;

 use crate::metrics::{REMOTE_EXT_REQUESTS_TOTAL, UNKNOWN_HTTP_STATUS};
@@ -158,14 +159,14 @@ fn parse_pg_version(human_version: &str) -> PostgresMajorVersion {
 pub async fn download_extension(
    ext_name: &str,
    ext_path: &RemotePath,
-    remote_ext_base_url: &str,
+    remote_ext_base_url: &Url,
    pgbin: &str,
 ) -> Result<u64> {
    info!("Download extension {:?} from {:?}", ext_name, ext_path);

    // TODO add retry logic
    let download_buffer =
-        match download_extension_tar(remote_ext_base_url, &ext_path.to_string()).await {
+        match download_extension_tar(remote_ext_base_url.as_str(), &ext_path.to_string()).await {
            Ok(buffer) => buffer,
            Err(error_message) => {
                return Err(anyhow::anyhow!(
--- a/compute_tools/src/pg_helpers.rs
+++ b/compute_tools/src/pg_helpers.rs
@@ -213,8 +213,10 @@ impl Escaping for PgIdent {

        // Find the first suitable tag that is not present in the string.
        // Postgres' max role/DB name length is 63 bytes, so even in the
-        // worst case it won't take long.
-        while self.contains(&format!("${tag}$")) || self.contains(&format!("${outer_tag}$")) {
+        // worst case it won't take long. Outer tag is always `tag + "x"`,
+        // so if `tag` is not present in the string, `outer_tag` is not
+        // present in the string either.
+        while self.contains(&tag.to_string()) {
            tag += "x";
            outer_tag = tag.clone() + "x";
        }
--- a/compute_tools/src/rsyslog.rs
+++ b/compute_tools/src/rsyslog.rs
@@ -27,6 +27,40 @@ fn get_rsyslog_pid() -> Option<String> {
    }
 }

+fn wait_for_rsyslog_pid() -> Result<String, anyhow::Error> {
+    const MAX_WAIT: Duration = Duration::from_secs(5);
+    const INITIAL_SLEEP: Duration = Duration::from_millis(2);
+
+    let mut sleep_duration = INITIAL_SLEEP;
+    let start = std::time::Instant::now();
+    let mut attempts = 1;
+
+    for attempt in 1.. {
+        attempts = attempt;
+        match get_rsyslog_pid() {
+            Some(pid) => return Ok(pid),
+            None => {
+                if start.elapsed() >= MAX_WAIT {
+                    break;
+                }
+                info!(
+                    "rsyslogd is not running, attempt {}. Sleeping for {} ms",
+                    attempt,
+                    sleep_duration.as_millis()
+                );
+                std::thread::sleep(sleep_duration);
+                sleep_duration *= 2;
+            }
+        }
+    }
+
+    Err(anyhow::anyhow!(
+        "rsyslogd is not running after waiting for {} seconds and {} attempts",
+        attempts,
+        start.elapsed().as_secs()
+    ))
+}
+
 // Restart rsyslogd to apply the new configuration.
 // This is necessary, because there is no other way to reload the rsyslog configuration.
 //
@@ -36,27 +70,29 @@ fn get_rsyslog_pid() -> Option<String> {
 // TODO: test it properly
 //
 fn restart_rsyslog() -> Result<()> {
-    let old_pid = get_rsyslog_pid().context("rsyslogd is not running")?;
-    info!("rsyslogd is running with pid: {}, restart it", old_pid);
-
    // kill it to restart
    let _ = Command::new("pkill")
        .arg("rsyslogd")
        .output()
-        .context("Failed to stop rsyslogd")?;
+        .context("Failed to restart rsyslogd")?;
+
+    // ensure rsyslogd is running
+    wait_for_rsyslog_pid()?;

    Ok(())
 }

 pub fn configure_audit_rsyslog(
    log_directory: String,
-    tag: Option<String>,
+    endpoint_id: &str,
+    project_id: &str,
    remote_endpoint: &str,
 ) -> Result<()> {
    let config_content: String = format!(
        include_str!("config_template/compute_audit_rsyslog_template.conf"),
        log_directory = log_directory,
-        tag = tag.unwrap_or("".to_string()),
+        endpoint_id = endpoint_id,
+        project_id = project_id,
        remote_endpoint = remote_endpoint
    );

@@ -131,15 +167,11 @@ pub fn configure_postgres_logs_export(conf: PostgresLogsRsyslogConfig) -> Result
        return Ok(());
    }

-    // When new config is empty we can simply remove the configuration file.
+    // Nothing to configure
    if new_config.is_empty() {
-        info!("removing rsyslog config file: {}", POSTGRES_LOGS_CONF_PATH);
-        match std::fs::remove_file(POSTGRES_LOGS_CONF_PATH) {
-            Ok(_) => {}
-            Err(err) if err.kind() == ErrorKind::NotFound => {}
-            Err(err) => return Err(err.into()),
-        }
-        restart_rsyslog()?;
+        // When the configuration is removed, PostgreSQL will stop sending data
+        // to the files watched by rsyslog, so restarting rsyslog is more effort
+        // than just ignoring this change.
        return Ok(());
    }

--- a/compute_tools/tests/pg_helpers_tests.rs
+++ b/compute_tools/tests/pg_helpers_tests.rs
@@ -71,6 +71,14 @@ test.escaping = 'here''s a backslash \\ and a quote '' and a double-quote " hoor
            ("name$$$", ("$x$name$$$$x$", "xx")),
            ("name$$$$", ("$x$name$$$$$x$", "xx")),
            ("name$x$", ("$xx$name$x$$xx$", "xxx")),
+            ("x", ("$xx$x$xx$", "xxx")),
+            ("xx", ("$xxx$xx$xxx$", "xxxx")),
+            ("$x", ("$xx$$x$xx$", "xxx")),
+            ("x$", ("$xx$x$$xx$", "xxx")),
+            ("$x$", ("$xx$$x$$xx$", "xxx")),
+            ("xx$", ("$xxx$xx$$xxx$", "xxxx")),
+            ("$xx", ("$xxx$$xx$xxx$", "xxxx")),
+            ("$xx$", ("$xxx$$xx$$xxx$", "xxxx")),
        ];

        for (input, expected) in test_cases {
--- a/control_plane/safekeepers.conf
+++ b/control_plane/safekeepers.conf
@@ -2,8 +2,10 @@
 [pageserver]
 listen_pg_addr = '127.0.0.1:64000'
 listen_http_addr = '127.0.0.1:9898'
+listen_grpc_addr = '127.0.0.1:51051'
 pg_auth_type = 'Trust'
 http_auth_type = 'Trust'
+grpc_auth_type = 'Trust'

 [[safekeepers]]
 id = 1
--- a/control_plane/simple.conf
+++ b/control_plane/simple.conf
@@ -4,8 +4,10 @@
 id=1
 listen_pg_addr = '127.0.0.1:64000'
 listen_http_addr = '127.0.0.1:9898'
+listen_grpc_addr = '127.0.0.1:51051'
 pg_auth_type = 'Trust'
 http_auth_type = 'Trust'
+grpc_auth_type = 'Trust'

 [[safekeepers]]
 id = 1
--- a/control_plane/src/bin/neon_local.rs
+++ b/control_plane/src/bin/neon_local.rs
@@ -32,6 +32,7 @@ use control_plane::storage_controller::{
 };
 use nix::fcntl::{Flock, FlockArg};
 use pageserver_api::config::{
+    DEFAULT_GRPC_LISTEN_PORT as DEFAULT_PAGESERVER_GRPC_PORT,
    DEFAULT_HTTP_LISTEN_PORT as DEFAULT_PAGESERVER_HTTP_PORT,
    DEFAULT_PG_LISTEN_PORT as DEFAULT_PAGESERVER_PG_PORT,
 };
@@ -1007,13 +1008,16 @@ fn handle_init(args: &InitCmdArgs) -> anyhow::Result<LocalEnv> {
                    let pageserver_id = NodeId(DEFAULT_PAGESERVER_ID.0 + i as u64);
                    let pg_port = DEFAULT_PAGESERVER_PG_PORT + i;
                    let http_port = DEFAULT_PAGESERVER_HTTP_PORT + i;
+                    let grpc_port = DEFAULT_PAGESERVER_GRPC_PORT + i;
                    NeonLocalInitPageserverConf {
                        id: pageserver_id,
                        listen_pg_addr: format!("127.0.0.1:{pg_port}"),
                        listen_http_addr: format!("127.0.0.1:{http_port}"),
                        listen_https_addr: None,
+                        listen_grpc_addr: Some(format!("127.0.0.1:{grpc_port}")),
                        pg_auth_type: AuthType::Trust,
                        http_auth_type: AuthType::Trust,
+                        grpc_auth_type: AuthType::Trust,
                        other: Default::default(),
                        // Typical developer machines use disks with slow fsync, and we don't care
                        // about data integrity: disable disk syncs.
@@ -1275,6 +1279,7 @@ async fn handle_timeline(cmd: &TimelineCmd, env: &mut local_env::LocalEnv) -> Re
                mode: pageserver_api::models::TimelineCreateRequestMode::Branch {
                    ancestor_timeline_id,
                    ancestor_start_lsn: start_lsn,
+                    read_only: false,
                    pg_version: None,
                },
            };
--- a/control_plane/src/local_env.rs
+++ b/control_plane/src/local_env.rs
@@ -278,8 +278,10 @@ pub struct PageServerConf {
    pub listen_pg_addr: String,
    pub listen_http_addr: String,
    pub listen_https_addr: Option<String>,
+    pub listen_grpc_addr: Option<String>,
    pub pg_auth_type: AuthType,
    pub http_auth_type: AuthType,
+    pub grpc_auth_type: AuthType,
    pub no_sync: bool,
 }

@@ -290,8 +292,10 @@ impl Default for PageServerConf {
            listen_pg_addr: String::new(),
            listen_http_addr: String::new(),
            listen_https_addr: None,
+            listen_grpc_addr: None,
            pg_auth_type: AuthType::Trust,
            http_auth_type: AuthType::Trust,
+            grpc_auth_type: AuthType::Trust,
            no_sync: false,
        }
    }
@@ -306,8 +310,10 @@ pub struct NeonLocalInitPageserverConf {
    pub listen_pg_addr: String,
    pub listen_http_addr: String,
    pub listen_https_addr: Option<String>,
+    pub listen_grpc_addr: Option<String>,
    pub pg_auth_type: AuthType,
    pub http_auth_type: AuthType,
+    pub grpc_auth_type: AuthType,
    #[serde(default, skip_serializing_if = "std::ops::Not::not")]
    pub no_sync: bool,
    #[serde(flatten)]
@@ -321,8 +327,10 @@ impl From<&NeonLocalInitPageserverConf> for PageServerConf {
            listen_pg_addr,
            listen_http_addr,
            listen_https_addr,
+            listen_grpc_addr,
            pg_auth_type,
            http_auth_type,
+            grpc_auth_type,
            no_sync,
            other: _,
        } = conf;
@@ -331,7 +339,9 @@ impl From<&NeonLocalInitPageserverConf> for PageServerConf {
            listen_pg_addr: listen_pg_addr.clone(),
            listen_http_addr: listen_http_addr.clone(),
            listen_https_addr: listen_https_addr.clone(),
+            listen_grpc_addr: listen_grpc_addr.clone(),
            pg_auth_type: *pg_auth_type,
+            grpc_auth_type: *grpc_auth_type,
            http_auth_type: *http_auth_type,
            no_sync: *no_sync,
        }
@@ -707,8 +717,10 @@ impl LocalEnv {
                    listen_pg_addr: String,
                    listen_http_addr: String,
                    listen_https_addr: Option<String>,
+                    listen_grpc_addr: Option<String>,
                    pg_auth_type: AuthType,
                    http_auth_type: AuthType,
+                    grpc_auth_type: AuthType,
                    #[serde(default)]
                    no_sync: bool,
                }
@@ -732,8 +744,10 @@ impl LocalEnv {
                    listen_pg_addr,
                    listen_http_addr,
                    listen_https_addr,
+                    listen_grpc_addr,
                    pg_auth_type,
                    http_auth_type,
+                    grpc_auth_type,
                    no_sync,
                } = config_toml;
                let IdentityTomlSubset {
@@ -750,8 +764,10 @@ impl LocalEnv {
                    listen_pg_addr,
                    listen_http_addr,
                    listen_https_addr,
+                    listen_grpc_addr,
                    pg_auth_type,
                    http_auth_type,
+                    grpc_auth_type,
                    no_sync,
                };
                pageservers.push(conf);
--- a/control_plane/src/pageserver.rs
+++ b/control_plane/src/pageserver.rs
@@ -129,7 +129,9 @@ impl PageServerNode {
            ));
        }

-        if conf.http_auth_type != AuthType::Trust || conf.pg_auth_type != AuthType::Trust {
+        if [conf.http_auth_type, conf.pg_auth_type, conf.grpc_auth_type]
+            .contains(&AuthType::NeonJWT)
+        {
            // Keys are generated in the toplevel repo dir, pageservers' workdirs
            // are one level below that, so refer to keys with ../
            overrides.push("auth_validation_public_key_path='../auth_public_key.pem'".to_owned());
@@ -546,6 +548,16 @@ impl PageServerNode {
                .map(serde_json::from_str)
                .transpose()
                .context("Falied to parse 'sampling_ratio'")?,
+            relsize_snapshot_cache_capacity: settings
+                .remove("relsize snapshot cache capacity")
+                .map(|x| x.parse::<usize>())
+                .transpose()
+                .context("Falied to parse 'relsize_snapshot_cache_capacity' as integer")?,
+            basebackup_cache_enabled: settings
+                .remove("basebackup_cache_enabled")
+                .map(|x| x.parse::<bool>())
+                .transpose()
+                .context("Failed to parse 'basebackup_cache_enabled' as bool")?,
        };
        if !settings.is_empty() {
            bail!("Unrecognized tenant settings: {settings:?}")
--- a/docker-compose/compute_wrapper/shell/compute.sh
+++ b/docker-compose/compute_wrapper/shell/compute.sh
@@ -20,7 +20,7 @@ first_path="$(ldconfig --verbose 2>/dev/null \
    | grep --invert-match ^$'\t' \
    | cut --delimiter=: --fields=1 \
    | head --lines=1)"
-test "$first_path" == '/usr/local/lib' || true # Remove the || true in a follow-up PR. Needed for backwards compat.
+test "$first_path" == '/usr/local/lib'

 echo "Waiting pageserver become ready."
 while ! nc -z pageserver 6400; do
--- a/docker-compose/ext-src/h3-pg-src/neon-test.sh
+++ b/docker-compose/ext-src/h3-pg-src/neon-test.sh
@@ -0,0 +1,16 @@
+#!/usr/bin/env bash
+set -ex
+cd "$(dirname "${0}")"
+PG_REGRESS=$(dirname "$(pg_config --pgxs)")/../test/regress/pg_regress
+dropdb --if-exists contrib_regression
+createdb contrib_regression
+cd h3_postgis/test
+psql -d contrib_regression -c "CREATE EXTENSION postgis" -c "CREATE EXTENSION postgis_raster" -c "CREATE EXTENSION h3" -c "CREATE EXTENSION h3_postgis"
+TESTS=$(echo sql/* | sed 's|sql/||g; s|\.sql||g')
+${PG_REGRESS} --use-existing --dbname contrib_regression ${TESTS}
+cd ../../h3/test
+TESTS=$(echo sql/* | sed 's|sql/||g; s|\.sql||g')
+dropdb --if-exists contrib_regression
+createdb contrib_regression
+psql -d contrib_regression -c "CREATE EXTENSION h3"
+${PG_REGRESS} --use-existing --dbname contrib_regression ${TESTS}
--- a/docker-compose/ext-src/h3-pg-src/test-upgrade.sh
+++ b/docker-compose/ext-src/h3-pg-src/test-upgrade.sh
@@ -0,0 +1,7 @@
+#!/bin/sh
+set -ex
+cd "$(dirname ${0})"
+PG_REGRESS=$(dirname "$(pg_config --pgxs)")/../test/regress/pg_regress
+cd h3/test
+TESTS=$(echo sql/* | sed 's|sql/||g; s|\.sql||g')
+${PG_REGRESS} --use-existing --inputdir=./ --bindir='/usr/local/pgsql/bin'  --dbname=contrib_regression  ${TESTS}
--- a/docker-compose/ext-src/online_advisor-src/neon-test.sh
+++ b/docker-compose/ext-src/online_advisor-src/neon-test.sh
@@ -0,0 +1,6 @@
+#!/bin/sh
+set -ex
+cd "$(dirname "${0}")"
+if [ -f Makefile ]; then
+  make installcheck
+fi
--- a/docker-compose/ext-src/online_advisor-src/regular-test.sh
+++ b/docker-compose/ext-src/online_advisor-src/regular-test.sh
@@ -0,0 +1,9 @@
+#!/bin/sh
+set -ex
+cd "$(dirname ${0})"
+[ -f Makefile ] || exit 0
+dropdb --if-exist contrib_regression
+createdb contrib_regression
+PG_REGRESS=$(dirname "$(pg_config --pgxs)")/../test/regress/pg_regress
+TESTS=$(echo sql/* | sed 's|sql/||g; s|\.sql||g')
+${PG_REGRESS} --use-existing --inputdir=./ --bindir='/usr/local/pgsql/bin' --dbname=contrib_regression ${TESTS}
--- a/docker-compose/test_extensions_upgrade.sh
+++ b/docker-compose/test_extensions_upgrade.sh
@@ -82,7 +82,8 @@ EXTENSIONS='[
 {"extname": "pg_ivm", "extdir": "pg_ivm-src"},
 {"extname": "pgjwt", "extdir": "pgjwt-src"},
 {"extname": "pgtap", "extdir": "pgtap-src"},
-{"extname": "pg_repack", "extdir": "pg_repack-src"}
+{"extname": "pg_repack", "extdir": "pg_repack-src"},
+{"extname": "h3", "extdir": "h3-pg-src"}
 ]'
 EXTNAMES=$(echo ${EXTENSIONS} | jq -r '.[].extname' | paste -sd ' ' -)
 COMPUTE_TAG=${NEW_COMPUTE_TAG} docker compose --profile test-extensions up --quiet-pull --build -d
--- a/endpoint_storage/src/app.rs
+++ b/endpoint_storage/src/app.rs
@@ -462,6 +462,8 @@ MC4CAQAwBQYDK2VwBCIEID/Drmc1AA6U/znNRWpF3zEGegOATQxfkdWxitcOMsIH
        if var(REAL_S3_ENV).is_ok() {
            assert!(body.contains("remote_storage_s3_deleted_objects_total"));
        }
+
+        #[cfg(target_os = "linux")]
        assert!(body.contains("process_threads"));
    }

--- a/libs/metrics/src/lib.rs
+++ b/libs/metrics/src/lib.rs
@@ -27,6 +27,7 @@ pub use prometheus::{

 pub mod launch_timestamp;
 mod wrappers;
+pub use prometheus;
 pub use wrappers::{CountedReader, CountedWriter};
 mod hll;
 pub use hll::{HyperLogLog, HyperLogLogState, HyperLogLogVec};
--- a/libs/pageserver_api/src/config.rs
+++ b/libs/pageserver_api/src/config.rs
@@ -8,6 +8,8 @@ pub const DEFAULT_PG_LISTEN_PORT: u16 = 64000;
 pub const DEFAULT_PG_LISTEN_ADDR: &str = formatcp!("127.0.0.1:{DEFAULT_PG_LISTEN_PORT}");
 pub const DEFAULT_HTTP_LISTEN_PORT: u16 = 9898;
 pub const DEFAULT_HTTP_LISTEN_ADDR: &str = formatcp!("127.0.0.1:{DEFAULT_HTTP_LISTEN_PORT}");
+// TODO: gRPC is disabled by default for now, but the port is used in neon_local.
+pub const DEFAULT_GRPC_LISTEN_PORT: u16 = 51051; // storage-broker already uses 50051

 use std::collections::HashMap;
 use std::num::{NonZeroU64, NonZeroUsize};
@@ -43,6 +45,21 @@ pub struct NodeMetadata {
    pub other: HashMap<String, serde_json::Value>,
 }

+/// PostHog integration config.
+#[derive(Debug, Clone, PartialEq, Eq, serde::Serialize, serde::Deserialize)]
+pub struct PostHogConfig {
+    /// PostHog project ID
+    pub project_id: String,
+    /// Server-side (private) API key
+    pub server_api_key: String,
+    /// Client-side (public) API key
+    pub client_api_key: String,
+    /// Private API URL
+    pub private_api_url: String,
+    /// Public API URL
+    pub public_api_url: String,
+}
+
 /// `pageserver.toml`
 ///
 /// We use serde derive with `#[serde(default)]` to generate a deserializer
@@ -104,6 +121,7 @@ pub struct ConfigToml {
    pub listen_pg_addr: String,
    pub listen_http_addr: String,
    pub listen_https_addr: Option<String>,
+    pub listen_grpc_addr: Option<String>,
    pub ssl_key_file: Utf8PathBuf,
    pub ssl_cert_file: Utf8PathBuf,
    #[serde(with = "humantime_serde")]
@@ -123,6 +141,7 @@ pub struct ConfigToml {
    pub http_auth_type: AuthType,
    #[serde_as(as = "serde_with::DisplayFromStr")]
    pub pg_auth_type: AuthType,
+    pub grpc_auth_type: AuthType,
    pub auth_validation_public_key_path: Option<Utf8PathBuf>,
    pub remote_storage: Option<RemoteStorageConfig>,
    pub tenant_config: TenantConfigToml,
@@ -182,7 +201,11 @@ pub struct ConfigToml {
    pub tracing: Option<Tracing>,
    pub enable_tls_page_service_api: bool,
    pub dev_mode: bool,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub posthog_config: Option<PostHogConfig>,
    pub timeline_import_config: TimelineImportConfig,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub basebackup_cache_config: Option<BasebackupCacheConfig>,
 }

 #[derive(Debug, Clone, PartialEq, Eq, serde::Serialize, serde::Deserialize)]
@@ -235,7 +258,7 @@ pub enum PageServiceProtocolPipelinedBatchingStrategy {
    ScatteredLsn,
 }

-#[derive(Debug, Clone, PartialEq, Eq, serde::Serialize, serde::Deserialize)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq, serde::Serialize, serde::Deserialize)]
 #[serde(tag = "mode", rename_all = "kebab-case")]
 pub enum GetVectoredConcurrentIo {
    /// The read path is fully sequential: layers are visited
@@ -308,6 +331,26 @@ pub struct TimelineImportConfig {
    pub import_job_checkpoint_threshold: NonZeroUsize,
 }

+#[derive(Debug, Clone, PartialEq, Eq, serde::Serialize, serde::Deserialize)]
+#[serde(default)]
+pub struct BasebackupCacheConfig {
+    #[serde(with = "humantime_serde")]
+    pub cleanup_period: Duration,
+    // FIXME: Support max_size_bytes.
+    // pub max_size_bytes: usize,
+    pub max_size_entries: i64,
+}
+
+impl Default for BasebackupCacheConfig {
+    fn default() -> Self {
+        Self {
+            cleanup_period: Duration::from_secs(60),
+            // max_size_bytes: 1024 * 1024 * 1024, // 1 GiB
+            max_size_entries: 1000,
+        }
+    }
+}
+
 pub mod statvfs {
    pub mod mock {
        #[derive(Debug, Clone, PartialEq, Eq, serde::Serialize, serde::Deserialize)]
@@ -491,6 +534,14 @@ pub struct TenantConfigToml {
    /// Tenant level performance sampling ratio override. Controls the ratio of get page requests
    /// that will get perf sampling for the tenant.
    pub sampling_ratio: Option<Ratio>,
+
+    /// Capacity of relsize snapshot cache (used by replicas).
+    pub relsize_snapshot_cache_capacity: usize,
+
+    /// Enable preparing basebackup on XLOG_CHECKPOINT_SHUTDOWN and using it in basebackup requests.
+    // FIXME: Remove skip_serializing_if when the feature is stable.
+    #[serde(skip_serializing_if = "std::ops::Not::not")]
+    pub basebackup_cache_enabled: bool,
 }

 pub mod defaults {
@@ -558,6 +609,7 @@ impl Default for ConfigToml {
            listen_pg_addr: (DEFAULT_PG_LISTEN_ADDR.to_string()),
            listen_http_addr: (DEFAULT_HTTP_LISTEN_ADDR.to_string()),
            listen_https_addr: (None),
+            listen_grpc_addr: None, // TODO: default to 127.0.0.1:51051
            ssl_key_file: Utf8PathBuf::from(DEFAULT_SSL_KEY_FILE),
            ssl_cert_file: Utf8PathBuf::from(DEFAULT_SSL_CERT_FILE),
            ssl_cert_reload_period: Duration::from_secs(60),
@@ -574,6 +626,7 @@ impl Default for ConfigToml {
            pg_distrib_dir: None, // Utf8PathBuf::from("./pg_install"), // TODO: formely, this was std::env::current_dir()
            http_auth_type: (AuthType::Trust),
            pg_auth_type: (AuthType::Trust),
+            grpc_auth_type: (AuthType::Trust),
            auth_validation_public_key_path: (None),
            remote_storage: None,
            broker_endpoint: (storage_broker::DEFAULT_ENDPOINT
@@ -664,6 +717,8 @@ impl Default for ConfigToml {
                import_job_soft_size_limit: NonZeroUsize::new(1024 * 1024 * 1024).unwrap(),
                import_job_checkpoint_threshold: NonZeroUsize::new(128).unwrap(),
            },
+            basebackup_cache_config: None,
+            posthog_config: None,
        }
    }
 }
@@ -730,6 +785,7 @@ pub mod tenant_conf_defaults {
    pub const DEFAULT_GC_COMPACTION_VERIFICATION: bool = true;
    pub const DEFAULT_GC_COMPACTION_INITIAL_THRESHOLD_KB: u64 = 5 * 1024 * 1024; // 5GB
    pub const DEFAULT_GC_COMPACTION_RATIO_PERCENT: u64 = 100;
+    pub const DEFAULT_RELSIZE_SNAPSHOT_CACHE_CAPACITY: usize = 1000;
 }

 impl Default for TenantConfigToml {
@@ -787,6 +843,8 @@ impl Default for TenantConfigToml {
            gc_compaction_initial_threshold_kb: DEFAULT_GC_COMPACTION_INITIAL_THRESHOLD_KB,
            gc_compaction_ratio_percent: DEFAULT_GC_COMPACTION_RATIO_PERCENT,
            sampling_ratio: None,
+            relsize_snapshot_cache_capacity: DEFAULT_RELSIZE_SNAPSHOT_CACHE_CAPACITY,
+            basebackup_cache_enabled: false,
        }
    }
 }
--- a/libs/pageserver_api/src/models.rs
+++ b/libs/pageserver_api/src/models.rs
@@ -354,6 +354,9 @@ pub struct ShardImportProgressV1 {
    pub completed: usize,
    /// Hash of the plan
    pub import_plan_hash: u64,
+    /// Soft limit for the job size
+    /// This needs to remain constant throughout the import
+    pub job_soft_size_limit: usize,
 }

 impl ShardImportStatus {
@@ -402,6 +405,8 @@ pub enum TimelineCreateRequestMode {
        // using a flattened enum, so, it was an accepted field, and
        // we continue to accept it by having it here.
        pg_version: Option<u32>,
+        #[serde(default, skip_serializing_if = "std::ops::Not::not")]
+        read_only: bool,
    },
    ImportPgdata {
        import_pgdata: TimelineCreateRequestModeImportPgdata,
@@ -630,6 +635,10 @@ pub struct TenantConfigPatch {
    pub gc_compaction_ratio_percent: FieldPatch<u64>,
    #[serde(skip_serializing_if = "FieldPatch::is_noop")]
    pub sampling_ratio: FieldPatch<Option<Ratio>>,
+    #[serde(skip_serializing_if = "FieldPatch::is_noop")]
+    pub relsize_snapshot_cache_capacity: FieldPatch<usize>,
+    #[serde(skip_serializing_if = "FieldPatch::is_noop")]
+    pub basebackup_cache_enabled: FieldPatch<bool>,
 }

 /// Like [`crate::config::TenantConfigToml`], but preserves the information
@@ -759,6 +768,12 @@ pub struct TenantConfig {

    #[serde(skip_serializing_if = "Option::is_none")]
    pub sampling_ratio: Option<Option<Ratio>>,
+
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub relsize_snapshot_cache_capacity: Option<usize>,
+
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub basebackup_cache_enabled: Option<bool>,
 }

 impl TenantConfig {
@@ -804,6 +819,8 @@ impl TenantConfig {
            mut gc_compaction_initial_threshold_kb,
            mut gc_compaction_ratio_percent,
            mut sampling_ratio,
+            mut relsize_snapshot_cache_capacity,
+            mut basebackup_cache_enabled,
        } = self;

        patch.checkpoint_distance.apply(&mut checkpoint_distance);
@@ -905,6 +922,12 @@ impl TenantConfig {
            .gc_compaction_ratio_percent
            .apply(&mut gc_compaction_ratio_percent);
        patch.sampling_ratio.apply(&mut sampling_ratio);
+        patch
+            .relsize_snapshot_cache_capacity
+            .apply(&mut relsize_snapshot_cache_capacity);
+        patch
+            .basebackup_cache_enabled
+            .apply(&mut basebackup_cache_enabled);

        Ok(Self {
            checkpoint_distance,
@@ -944,6 +967,8 @@ impl TenantConfig {
            gc_compaction_initial_threshold_kb,
            gc_compaction_ratio_percent,
            sampling_ratio,
+            relsize_snapshot_cache_capacity,
+            basebackup_cache_enabled,
        })
    }

@@ -1052,6 +1077,12 @@ impl TenantConfig {
                .gc_compaction_ratio_percent
                .unwrap_or(global_conf.gc_compaction_ratio_percent),
            sampling_ratio: self.sampling_ratio.unwrap_or(global_conf.sampling_ratio),
+            relsize_snapshot_cache_capacity: self
+                .relsize_snapshot_cache_capacity
+                .unwrap_or(global_conf.relsize_snapshot_cache_capacity),
+            basebackup_cache_enabled: self
+                .basebackup_cache_enabled
+                .unwrap_or(global_conf.basebackup_cache_enabled),
        }
    }
 }
--- a/libs/posthog_client_lite/Cargo.toml
+++ b/libs/posthog_client_lite/Cargo.toml
@@ -6,9 +6,14 @@ license.workspace = true

 [dependencies]
 anyhow.workspace = true
+arc-swap.workspace = true
 reqwest.workspace = true
-serde.workspace = true
 serde_json.workspace = true
+serde.workspace = true
 sha2.workspace = true
-workspace_hack.workspace = true
 thiserror.workspace = true
+tokio = { workspace = true, features = ["process", "sync", "fs", "rt", "io-util", "time"] }
+tokio-util.workspace = true
+tracing-utils.workspace = true
+tracing.workspace = true
+workspace_hack.workspace = true
--- a/libs/posthog_client_lite/src/background_loop.rs
+++ b/libs/posthog_client_lite/src/background_loop.rs
@@ -0,0 +1,64 @@
+//! A background loop that fetches feature flags from PostHog and updates the feature store.
+
+use std::{sync::Arc, time::Duration};
+
+use arc_swap::ArcSwap;
+use tokio_util::sync::CancellationToken;
+use tracing::{Instrument, info_span};
+
+use crate::{FeatureStore, 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>,
+    cancel: CancellationToken,
+}
+
+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())),
+            cancel: shutdown_pageserver,
+        }
+    }
+
+    pub fn spawn(self: Arc<Self>, handle: &tokio::runtime::Handle, refresh_period: Duration) {
+        let this = self.clone();
+        let cancel = self.cancel.clone();
+        handle.spawn(
+            async move {
+                tracing::info!("Starting PostHog feature resolver");
+                let mut ticker = tokio::time::interval(refresh_period);
+                ticker.set_missed_tick_behavior(tokio::time::MissedTickBehavior::Skip);
+                loop {
+                    tokio::select! {
+                        _ = ticker.tick() => {}
+                        _ = cancel.cancelled() => break
+                    }
+                    let resp = match this
+                        .posthog_client
+                        .get_feature_flags_local_evaluation()
+                        .await
+                    {
+                        Ok(resp) => resp,
+                        Err(e) => {
+                            tracing::warn!("Cannot get feature flags: {}", e);
+                            continue;
+                        }
+                    };
+                    let feature_store = FeatureStore::new_with_flags(resp.flags);
+                    this.feature_store.store(Arc::new(feature_store));
+                    tracing::info!("Feature flag updated");
+                }
+                tracing::info!("PostHog feature resolver stopped");
+            }
+            .instrument(info_span!("posthog_feature_resolver")),
+        );
+    }
+
+    pub fn feature_store(&self) -> Arc<FeatureStore> {
+        self.feature_store.load_full()
+    }
+}
--- a/libs/posthog_client_lite/src/lib.rs
+++ b/libs/posthog_client_lite/src/lib.rs
@@ -1,5 +1,9 @@
 //! A lite version of the PostHog client that only supports local evaluation of feature flags.

+mod background_loop;
+
+pub use background_loop::FeatureResolverBackgroundLoop;
+
 use std::collections::HashMap;

 use serde::{Deserialize, Serialize};
@@ -20,8 +24,7 @@ pub enum PostHogEvaluationError {

 #[derive(Deserialize)]
 pub struct LocalEvaluationResponse {
-    #[allow(dead_code)]
-    flags: Vec<LocalEvaluationFlag>,
+    pub flags: Vec<LocalEvaluationFlag>,
 }

 #[derive(Deserialize)]
@@ -34,7 +37,7 @@ pub struct LocalEvaluationFlag {
 #[derive(Deserialize)]
 pub struct LocalEvaluationFlagFilters {
    groups: Vec<LocalEvaluationFlagFilterGroup>,
-    multivariate: LocalEvaluationFlagMultivariate,
+    multivariate: Option<LocalEvaluationFlagMultivariate>,
 }

 #[derive(Deserialize)]
@@ -94,6 +97,12 @@ impl FeatureStore {
        }
    }

+    pub fn new_with_flags(flags: Vec<LocalEvaluationFlag>) -> Self {
+        let mut store = Self::new();
+        store.set_flags(flags);
+        store
+    }
+
    pub fn set_flags(&mut self, flags: Vec<LocalEvaluationFlag>) {
        self.flags.clear();
        for flag in flags {
@@ -245,7 +254,7 @@ impl FeatureStore {
        }
    }

-    /// Evaluate a multivariate feature flag. Returns `None` if the flag is not available or if there are errors
+    /// Evaluate a multivariate feature flag. Returns an error if the flag is not available or if there are errors
    /// during the evaluation.
    ///
    /// The parsing logic is as follows:
@@ -263,10 +272,15 @@ impl FeatureStore {
    /// Example: we have a multivariate flag with 3 groups of the configured global rollout percentage: A (10%), B (20%), C (70%).
    /// There is a single group with a condition that has a rollout percentage of 10% and it does not have a variant override.
    /// Then, we will have 1% of the users evaluated to A, 2% to B, and 7% to C.
+    ///
+    /// Error handling: the caller should inspect the error and decide the behavior when a feature flag
+    /// cannot be evaluated (i.e., default to false if it cannot be resolved). The error should *not* be
+    /// propagated beyond where the feature flag gets resolved.
    pub fn evaluate_multivariate(
        &self,
        flag_key: &str,
        user_id: &str,
+        properties: &HashMap<String, PostHogFlagFilterPropertyValue>,
    ) -> Result<String, PostHogEvaluationError> {
        let hash_on_global_rollout_percentage =
            Self::consistent_hash(user_id, flag_key, "multivariate");
@@ -276,10 +290,39 @@ impl FeatureStore {
            flag_key,
            hash_on_global_rollout_percentage,
            hash_on_group_rollout_percentage,
-            &HashMap::new(),
+            properties,
        )
    }

+    /// Evaluate a boolean feature flag. Returns  an error if the flag is not available or if there are errors
+    /// during the evaluation.
+    ///
+    /// The parsing logic is as follows:
+    ///
+    /// * Generate a consistent hash for the tenant-feature.
+    /// * Match each filter group.
+    ///   - If a group is matched, it will first determine whether the user is in the range of the rollout
+    ///     percentage.
+    ///   - If the hash falls within the group's rollout percentage, return true.
+    /// * Otherwise, continue with the next group until all groups are evaluated and no group is within the
+    ///   rollout percentage.
+    /// * If there are no matching groups, return an error.
+    ///
+    /// Returns `Ok(())` if the feature flag evaluates to true. In the future, it will return a payload.
+    ///
+    /// Error handling: the caller should inspect the error and decide the behavior when a feature flag
+    /// cannot be evaluated (i.e., default to false if it cannot be resolved). The error should *not* be
+    /// propagated beyond where the feature flag gets resolved.
+    pub fn evaluate_boolean(
+        &self,
+        flag_key: &str,
+        user_id: &str,
+        properties: &HashMap<String, PostHogFlagFilterPropertyValue>,
+    ) -> Result<(), PostHogEvaluationError> {
+        let hash_on_global_rollout_percentage = Self::consistent_hash(user_id, flag_key, "boolean");
+        self.evaluate_boolean_inner(flag_key, hash_on_global_rollout_percentage, properties)
+    }
+
    /// Evaluate a multivariate feature flag. Note that we directly take the mapped user ID
    /// (a consistent hash ranging from 0 to 1) so that it is easier to use it in the tests
    /// and avoid duplicate computations.
@@ -306,6 +349,11 @@ impl FeatureStore {
                    flag_key
                )));
            }
+            let Some(ref multivariate) = flag_config.filters.multivariate else {
+                return Err(PostHogEvaluationError::Internal(format!(
+                    "No multivariate available, should use evaluate_boolean?: {flag_key}"
+                )));
+            };
            // TODO: sort the groups so that variant overrides always get evaluated first and it follows the PostHog
            // Python SDK behavior; for now we do not configure conditions without variant overrides in Neon so it
            // does not matter.
@@ -314,7 +362,7 @@ impl FeatureStore {
                    GroupEvaluationResult::MatchedAndOverride(variant) => return Ok(variant),
                    GroupEvaluationResult::MatchedAndEvaluate => {
                        let mut percentage = 0;
-                        for variant in &flag_config.filters.multivariate.variants {
+                        for variant in &multivariate.variants {
                            percentage += variant.rollout_percentage;
                            if self
                                .evaluate_percentage(hash_on_global_rollout_percentage, percentage)
@@ -342,6 +390,89 @@ impl FeatureStore {
            )))
        }
    }
+
+    /// Evaluate a multivariate feature flag. Note that we directly take the mapped user ID
+    /// (a consistent hash ranging from 0 to 1) so that it is easier to use it in the tests
+    /// and avoid duplicate computations.
+    ///
+    /// Use a different consistent hash for evaluating the group rollout percentage.
+    /// The behavior: if the condition is set to rolling out to 10% of the users, and
+    /// we set the variant A to 20% in the global config, then 2% of the total users will
+    /// be evaluated to variant A.
+    ///
+    /// Note that the hash to determine group rollout percentage is shared across all groups. So if we have two
+    /// exactly-the-same conditions with 10% and 20% rollout percentage respectively, a total of 20% of the users
+    /// will be evaluated (versus 30% if group evaluation is done independently).
+    pub(crate) fn evaluate_boolean_inner(
+        &self,
+        flag_key: &str,
+        hash_on_global_rollout_percentage: f64,
+        properties: &HashMap<String, PostHogFlagFilterPropertyValue>,
+    ) -> Result<(), PostHogEvaluationError> {
+        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
+                )));
+            }
+            if flag_config.filters.multivariate.is_some() {
+                return Err(PostHogEvaluationError::Internal(format!(
+                    "This looks like a multivariate flag, should use evaluate_multivariate?: {flag_key}"
+                )));
+            };
+            // TODO: sort the groups so that variant overrides always get evaluated first and it follows the PostHog
+            // Python SDK behavior; for now we do not configure conditions without variant overrides in Neon so it
+            // does not matter.
+            for group in &flag_config.filters.groups {
+                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
+                        )));
+                    }
+                    GroupEvaluationResult::MatchedAndEvaluate => {
+                        return Ok(());
+                    }
+                    GroupEvaluationResult::Unmatched => continue,
+                }
+            }
+            // If no group is matched, the feature is not available, and up to the caller to decide what to do.
+            Err(PostHogEvaluationError::NoConditionGroupMatched)
+        } else {
+            // The feature flag is not available yet
+            Err(PostHogEvaluationError::NotAvailable(format!(
+                "Not found in the local evaluation spec: {}",
+                flag_key
+            )))
+        }
+    }
+
+    /// Infer whether a feature flag is a boolean flag by checking if it has a multivariate filter.
+    pub fn is_feature_flag_boolean(&self, flag_key: &str) -> Result<bool, PostHogEvaluationError> {
+        if let Some(flag_config) = self.flags.get(flag_key) {
+            Ok(flag_config.filters.multivariate.is_none())
+        } else {
+            Err(PostHogEvaluationError::NotAvailable(format!(
+                "Not found in the local evaluation spec: {}",
+                flag_key
+            )))
+        }
+    }
+}
+
+pub struct PostHogClientConfig {
+    /// The server API key.
+    pub server_api_key: String,
+    /// The client API key.
+    pub client_api_key: String,
+    /// The project ID.
+    pub project_id: String,
+    /// The private API URL.
+    pub private_api_url: String,
+    /// The public API URL.
+    pub public_api_url: String,
 }

 /// A lite PostHog client.
@@ -360,37 +491,16 @@ impl FeatureStore {
 /// want to report the feature flag usage back to PostHog. The current plan is to use PostHog only as an UI to
 /// configure feature flags so it is very likely that the client API will not be used.
 pub struct PostHogClient {
-    /// The server API key.
-    server_api_key: String,
-    /// The client API key.
-    client_api_key: String,
-    /// The project ID.
-    project_id: String,
-    /// The private API URL.
-    private_api_url: String,
-    /// The public API URL.
-    public_api_url: String,
+    /// The config.
+    config: PostHogClientConfig,
    /// The HTTP client.
    client: reqwest::Client,
 }

 impl PostHogClient {
-    pub fn new(
-        server_api_key: String,
-        client_api_key: String,
-        project_id: String,
-        private_api_url: String,
-        public_api_url: String,
-    ) -> Self {
+    pub fn new(config: PostHogClientConfig) -> Self {
        let client = reqwest::Client::new();
-        Self {
-            server_api_key,
-            client_api_key,
-            project_id,
-            private_api_url,
-            public_api_url,
-            client,
-        }
+        Self { config, client }
    }

    pub fn new_with_us_region(
@@ -398,13 +508,13 @@ impl PostHogClient {
        client_api_key: String,
        project_id: String,
    ) -> Self {
-        Self::new(
+        Self::new(PostHogClientConfig {
            server_api_key,
            client_api_key,
            project_id,
-            "https://us.posthog.com".to_string(),
-            "https://us.i.posthog.com".to_string(),
-        )
+            private_api_url: "https://us.posthog.com".to_string(),
+            public_api_url: "https://us.i.posthog.com".to_string(),
+        })
    }

    /// Fetch the feature flag specs from the server.
@@ -422,15 +532,23 @@ impl PostHogClient {
        // with bearer token of self.server_api_key
        let url = format!(
            "{}/api/projects/{}/feature_flags/local_evaluation",
-            self.private_api_url, self.project_id
+            self.config.private_api_url, self.config.project_id
        );
        let response = self
            .client
            .get(url)
-            .bearer_auth(&self.server_api_key)
+            .bearer_auth(&self.config.server_api_key)
            .send()
            .await?;
+        let status = response.status();
        let body = response.text().await?;
+        if !status.is_success() {
+            return Err(anyhow::anyhow!(
+                "Failed to get feature flags: {}, {}",
+                status,
+                body
+            ));
+        }
        Ok(serde_json::from_str(&body)?)
    }

@@ -446,11 +564,11 @@ impl PostHogClient {
    ) -> anyhow::Result<()> {
        // PUBLIC_URL/capture/
        // with bearer token of self.client_api_key
-        let url = format!("{}/capture/", self.public_api_url);
+        let url = format!("{}/capture/", self.config.public_api_url);
        self.client
            .post(url)
            .body(serde_json::to_string(&json!({
-                "api_key": self.client_api_key,
+                "api_key": self.config.client_api_key,
                "distinct_id": distinct_id,
                "event": event,
                "properties": properties,
@@ -467,95 +585,162 @@ mod tests {

    fn data() -> &'static str {
        r#"{
-            "flags": [
-                {
-                    "id": 132794,
-                    "team_id": 152860,
-                    "name": "",
-                    "key": "gc-compaction",
-                    "filters": {
-                        "groups": [
-                            {
-                                "variant": "enabled-stage-2",
-                                "properties": [
-                                    {
-                                        "key": "plan_type",
-                                        "type": "person",
-                                        "value": [
-                                            "free"
-                                        ],
-                                        "operator": "exact"
-                                    },
-                                    {
-                                        "key": "pageserver_remote_size",
-                                        "type": "person",
-                                        "value": "10000000",
-                                        "operator": "lt"
-                                    }
-                                ],
-                                "rollout_percentage": 50
-                            },
-                            {
-                                "properties": [
-                                    {
-                                        "key": "plan_type",
-                                        "type": "person",
-                                        "value": [
-                                            "free"
-                                        ],
-                                        "operator": "exact"
-                                    },
-                                    {
-                                        "key": "pageserver_remote_size",
-                                        "type": "person",
-                                        "value": "10000000",
-                                        "operator": "lt"
-                                    }
-                                ],
-                                "rollout_percentage": 80
-                            }
-                        ],
-                        "payloads": {},
-                        "multivariate": {
-                            "variants": [
-                                {
-                                    "key": "disabled",
-                                    "name": "",
-                                    "rollout_percentage": 90
-                                },
-                                {
-                                    "key": "enabled-stage-1",
-                                    "name": "",
-                                    "rollout_percentage": 10
-                                },
-                                {
-                                    "key": "enabled-stage-2",
-                                    "name": "",
-                                    "rollout_percentage": 0
-                                },
-                                {
-                                    "key": "enabled-stage-3",
-                                    "name": "",
-                                    "rollout_percentage": 0
-                                },
-                                {
-                                    "key": "enabled",
-                                    "name": "",
-                                    "rollout_percentage": 0
-                                }
-                            ]
-                        }
-                    },
-                    "deleted": false,
-                    "active": true,
-                    "ensure_experience_continuity": false,
-                    "has_encrypted_payloads": false,
-                    "version": 6
-                }
+  "flags": [
+    {
+      "id": 141807,
+      "team_id": 152860,
+      "name": "",
+      "key": "image-compaction-boundary",
+      "filters": {
+        "groups": [
+          {
+            "variant": null,
+            "properties": [
+              {
+                "key": "plan_type",
+                "type": "person",
+                "value": [
+                  "free"
+                ],
+                "operator": "exact"
+              }
            ],
-            "group_type_mapping": {},
-            "cohorts": {}
-        }"#
+            "rollout_percentage": 40
+          },
+          {
+            "variant": null,
+            "properties": [],
+            "rollout_percentage": 10
+          }
+        ],
+        "payloads": {},
+        "multivariate": null
+      },
+      "deleted": false,
+      "active": true,
+      "ensure_experience_continuity": false,
+      "has_encrypted_payloads": false,
+      "version": 1
+    },
+    {
+      "id": 135586,
+      "team_id": 152860,
+      "name": "",
+      "key": "boolean-flag",
+      "filters": {
+        "groups": [
+          {
+            "variant": null,
+            "properties": [
+              {
+                "key": "plan_type",
+                "type": "person",
+                "value": [
+                  "free"
+                ],
+                "operator": "exact"
+              }
+            ],
+            "rollout_percentage": 47
+          }
+        ],
+        "payloads": {},
+        "multivariate": null
+      },
+      "deleted": false,
+      "active": true,
+      "ensure_experience_continuity": false,
+      "has_encrypted_payloads": false,
+      "version": 1
+    },
+    {
+      "id": 132794,
+      "team_id": 152860,
+      "name": "",
+      "key": "gc-compaction",
+      "filters": {
+        "groups": [
+          {
+            "variant": "enabled-stage-2",
+            "properties": [
+              {
+                "key": "plan_type",
+                "type": "person",
+                "value": [
+                  "free"
+                ],
+                "operator": "exact"
+              },
+              {
+                "key": "pageserver_remote_size",
+                "type": "person",
+                "value": "10000000",
+                "operator": "lt"
+              }
+            ],
+             "rollout_percentage": 50
+          },
+          {
+            "properties": [
+              {
+                "key": "plan_type",
+                "type": "person",
+                "value": [
+                  "free"
+                ],
+                "operator": "exact"
+              },
+              {
+                "key": "pageserver_remote_size",
+                "type": "person",
+                "value": "10000000",
+                "operator": "lt"
+              }
+            ],
+            "rollout_percentage": 80
+          }
+        ],
+        "payloads": {},
+        "multivariate": {
+          "variants": [
+            {
+              "key": "disabled",
+              "name": "",
+              "rollout_percentage": 90
+            },
+            {
+              "key": "enabled-stage-1",
+              "name": "",
+              "rollout_percentage": 10
+            },
+            {
+              "key": "enabled-stage-2",
+              "name": "",
+              "rollout_percentage": 0
+            },
+            {
+              "key": "enabled-stage-3",
+              "name": "",
+              "rollout_percentage": 0
+            },
+            {
+              "key": "enabled",
+              "name": "",
+              "rollout_percentage": 0
+            }
+          ]
+        }
+      },
+      "deleted": false,
+      "active": true,
+      "ensure_experience_continuity": false,
+      "has_encrypted_payloads": false,
+      "version": 7
+    }
+  ],
+  "group_type_mapping": {},
+  "cohorts": {}
+}"#
    }

    #[test]
@@ -631,4 +816,125 @@ mod tests {
            Err(PostHogEvaluationError::NoConditionGroupMatched)
        ),);
    }
+
+    #[test]
+    fn evaluate_boolean_1() {
+        // The `boolean-flag` feature flag only has one group that matches on the free user.
+
+        let mut store = FeatureStore::new();
+        let response: LocalEvaluationResponse = serde_json::from_str(data()).unwrap();
+        store.set_flags(response.flags);
+
+        // This lacks the required properties and cannot be evaluated.
+        let variant = store.evaluate_boolean_inner("boolean-flag", 1.00, &HashMap::new());
+        assert!(matches!(
+            variant,
+            Err(PostHogEvaluationError::NotAvailable(_))
+        ),);
+
+        let properties_unmatched = HashMap::from([
+            (
+                "plan_type".to_string(),
+                PostHogFlagFilterPropertyValue::String("paid".to_string()),
+            ),
+            (
+                "pageserver_remote_size".to_string(),
+                PostHogFlagFilterPropertyValue::Number(1000.0),
+            ),
+        ]);
+
+        // This does not match any group so there will be an error.
+        let variant = store.evaluate_boolean_inner("boolean-flag", 1.00, &properties_unmatched);
+        assert!(matches!(
+            variant,
+            Err(PostHogEvaluationError::NoConditionGroupMatched)
+        ),);
+
+        let properties = HashMap::from([
+            (
+                "plan_type".to_string(),
+                PostHogFlagFilterPropertyValue::String("free".to_string()),
+            ),
+            (
+                "pageserver_remote_size".to_string(),
+                PostHogFlagFilterPropertyValue::Number(1000.0),
+            ),
+        ]);
+
+        // It matches the first group as 0.10 <= 0.50 and the properties are matched. Then it gets evaluated to the variant override.
+        let variant = store.evaluate_boolean_inner("boolean-flag", 0.10, &properties);
+        assert!(variant.is_ok());
+
+        // It matches the group conditions but not the group rollout percentage.
+        let variant = store.evaluate_boolean_inner("boolean-flag", 1.00, &properties);
+        assert!(matches!(
+            variant,
+            Err(PostHogEvaluationError::NoConditionGroupMatched)
+        ),);
+    }
+
+    #[test]
+    fn evaluate_boolean_2() {
+        // The `image-compaction-boundary` feature flag has one group that matches on the free user and a group that matches on all users.
+
+        let mut store = FeatureStore::new();
+        let response: LocalEvaluationResponse = serde_json::from_str(data()).unwrap();
+        store.set_flags(response.flags);
+
+        // This lacks the required properties and cannot be evaluated.
+        let variant =
+            store.evaluate_boolean_inner("image-compaction-boundary", 1.00, &HashMap::new());
+        assert!(matches!(
+            variant,
+            Err(PostHogEvaluationError::NotAvailable(_))
+        ),);
+
+        let properties_unmatched = HashMap::from([
+            (
+                "plan_type".to_string(),
+                PostHogFlagFilterPropertyValue::String("paid".to_string()),
+            ),
+            (
+                "pageserver_remote_size".to_string(),
+                PostHogFlagFilterPropertyValue::Number(1000.0),
+            ),
+        ]);
+
+        // This does not match the filtered group but the all user group.
+        let variant =
+            store.evaluate_boolean_inner("image-compaction-boundary", 1.00, &properties_unmatched);
+        assert!(matches!(
+            variant,
+            Err(PostHogEvaluationError::NoConditionGroupMatched)
+        ),);
+        let variant =
+            store.evaluate_boolean_inner("image-compaction-boundary", 0.05, &properties_unmatched);
+        assert!(variant.is_ok());
+
+        let properties = HashMap::from([
+            (
+                "plan_type".to_string(),
+                PostHogFlagFilterPropertyValue::String("free".to_string()),
+            ),
+            (
+                "pageserver_remote_size".to_string(),
+                PostHogFlagFilterPropertyValue::Number(1000.0),
+            ),
+        ]);
+
+        // It matches the first group as 0.30 <= 0.40 and the properties are matched. Then it gets evaluated to the variant override.
+        let variant = store.evaluate_boolean_inner("image-compaction-boundary", 0.30, &properties);
+        assert!(variant.is_ok());
+
+        // It matches the group conditions but not the group rollout percentage.
+        let variant = store.evaluate_boolean_inner("image-compaction-boundary", 1.00, &properties);
+        assert!(matches!(
+            variant,
+            Err(PostHogEvaluationError::NoConditionGroupMatched)
+        ),);
+
+        // It matches the second "all" group conditions.
+        let variant = store.evaluate_boolean_inner("image-compaction-boundary", 0.09, &properties);
+        assert!(variant.is_ok());
+    }
 }
--- a/libs/proxy/postgres-protocol2/src/message/frontend.rs
+++ b/libs/proxy/postgres-protocol2/src/message/frontend.rs
@@ -25,6 +25,7 @@ where
    Ok(())
 }

+#[derive(Debug)]
 pub enum BindError {
    Conversion(Box<dyn Error + marker::Sync + Send>),
    Serialization(io::Error),
@@ -288,6 +289,12 @@ pub fn sync(buf: &mut BytesMut) {
    write_body(buf, |_| Ok::<(), io::Error>(())).unwrap();
 }

+#[inline]
+pub fn flush(buf: &mut BytesMut) {
+    buf.put_u8(b'H');
+    write_body(buf, |_| Ok::<(), io::Error>(())).unwrap();
+}
+
 #[inline]
 pub fn terminate(buf: &mut BytesMut) {
    buf.put_u8(b'X');
--- a/libs/proxy/postgres-types2/src/lib.rs
+++ b/libs/proxy/postgres-types2/src/lib.rs
@@ -9,7 +9,6 @@ use std::error::Error;
 use std::fmt;
 use std::sync::Arc;

-use bytes::BytesMut;
 use fallible_iterator::FallibleIterator;
 #[doc(inline)]
 pub use postgres_protocol2::Oid;
@@ -27,41 +26,6 @@ macro_rules! accepts {
    )
 }

-/// Generates an implementation of `ToSql::to_sql_checked`.
-///
-/// All `ToSql` implementations should use this macro.
-macro_rules! to_sql_checked {
-    () => {
-        fn to_sql_checked(
-            &self,
-            ty: &$crate::Type,
-            out: &mut $crate::private::BytesMut,
-        ) -> ::std::result::Result<
-            $crate::IsNull,
-            Box<dyn ::std::error::Error + ::std::marker::Sync + ::std::marker::Send>,
-        > {
-            $crate::__to_sql_checked(self, ty, out)
-        }
-    };
-}
-
-// WARNING: this function is not considered part of this crate's public API.
-// It is subject to change at any time.
-#[doc(hidden)]
-pub fn __to_sql_checked<T>(
-    v: &T,
-    ty: &Type,
-    out: &mut BytesMut,
-) -> Result<IsNull, Box<dyn Error + Sync + Send>>
-where
-    T: ToSql,
-{
-    if !T::accepts(ty) {
-        return Err(Box::new(WrongType::new::<T>(ty.clone())));
-    }
-    v.to_sql(ty, out)
-}
-
 // mod pg_lsn;
 #[doc(hidden)]
 pub mod private;
@@ -142,7 +106,7 @@ pub enum Kind {
    /// An array type along with the type of its elements.
    Array(Type),
    /// A range type along with the type of its elements.
-    Range(Type),
+    Range(Oid),
    /// A multirange type along with the type of its elements.
    Multirange(Type),
    /// A domain type along with its underlying type.
@@ -377,43 +341,6 @@ pub enum IsNull {
    No,
 }

-/// A trait for types that can be converted into Postgres values.
-pub trait ToSql: fmt::Debug {
-    /// Converts the value of `self` into the binary format of the specified
-    /// Postgres `Type`, appending it to `out`.
-    ///
-    /// The caller of this method is responsible for ensuring that this type
-    /// is compatible with the Postgres `Type`.
-    ///
-    /// The return value indicates if this value should be represented as
-    /// `NULL`. If this is the case, implementations **must not** write
-    /// anything to `out`.
-    fn to_sql(&self, ty: &Type, out: &mut BytesMut) -> Result<IsNull, Box<dyn Error + Sync + Send>>
-    where
-        Self: Sized;
-
-    /// Determines if a value of this type can be converted to the specified
-    /// Postgres `Type`.
-    fn accepts(ty: &Type) -> bool
-    where
-        Self: Sized;
-
-    /// An adaptor method used internally by Rust-Postgres.
-    ///
-    /// *All* implementations of this method should be generated by the
-    /// `to_sql_checked!()` macro.
-    fn to_sql_checked(
-        &self,
-        ty: &Type,
-        out: &mut BytesMut,
-    ) -> Result<IsNull, Box<dyn Error + Sync + Send>>;
-
-    /// Specify the encode format
-    fn encode_format(&self, _ty: &Type) -> Format {
-        Format::Binary
-    }
-}
-
 /// Supported Postgres message format types
 ///
 /// Using Text format in a message assumes a Postgres `SERVER_ENCODING` of `UTF8`
@@ -424,52 +351,3 @@ pub enum Format {
    /// Compact, typed binary format
    Binary,
 }
-
-impl ToSql for &str {
-    fn to_sql(&self, ty: &Type, w: &mut BytesMut) -> Result<IsNull, Box<dyn Error + Sync + Send>> {
-        match *ty {
-            ref ty if ty.name() == "ltree" => types::ltree_to_sql(self, w),
-            ref ty if ty.name() == "lquery" => types::lquery_to_sql(self, w),
-            ref ty if ty.name() == "ltxtquery" => types::ltxtquery_to_sql(self, w),
-            _ => types::text_to_sql(self, w),
-        }
-        Ok(IsNull::No)
-    }
-
-    fn accepts(ty: &Type) -> bool {
-        match *ty {
-            Type::VARCHAR | Type::TEXT | Type::BPCHAR | Type::NAME | Type::UNKNOWN => true,
-            ref ty
-                if (ty.name() == "citext"
-                    || ty.name() == "ltree"
-                    || ty.name() == "lquery"
-                    || ty.name() == "ltxtquery") =>
-            {
-                true
-            }
-            _ => false,
-        }
-    }
-
-    to_sql_checked!();
-}
-
-macro_rules! simple_to {
-    ($t:ty, $f:ident, $($expected:ident),+) => {
-        impl ToSql for $t {
-            fn to_sql(&self,
-                      _: &Type,
-                      w: &mut BytesMut)
-                      -> Result<IsNull, Box<dyn Error + Sync + Send>> {
-                types::$f(*self, w);
-                Ok(IsNull::No)
-            }
-
-            accepts!($($expected),+);
-
-            to_sql_checked!();
-        }
-    }
-}
-
-simple_to!(u32, oid_to_sql, OID);
--- a/libs/proxy/postgres-types2/src/type_gen.rs
+++ b/libs/proxy/postgres-types2/src/type_gen.rs
@@ -393,7 +393,7 @@ impl Inner {
        }
    }

-    pub fn oid(&self) -> Oid {
+    pub const fn const_oid(&self) -> Oid {
        match *self {
            Inner::Bool => 16,
            Inner::Bytea => 17,
@@ -580,7 +580,14 @@ impl Inner {
            Inner::TstzmultiRangeArray => 6153,
            Inner::DatemultiRangeArray => 6155,
            Inner::Int8multiRangeArray => 6157,
+            Inner::Other(_) => u32::MAX,
+        }
+    }
+
+    pub fn oid(&self) -> Oid {
+        match *self {
            Inner::Other(ref u) => u.oid,
+            _ => self.const_oid(),
        }
    }

@@ -727,17 +734,17 @@ impl Inner {
            Inner::JsonbArray => &Kind::Array(Type(Inner::Jsonb)),
            Inner::AnyRange => &Kind::Pseudo,
            Inner::EventTrigger => &Kind::Pseudo,
-            Inner::Int4Range => &Kind::Range(Type(Inner::Int4)),
+            Inner::Int4Range => &const { Kind::Range(Inner::Int4.const_oid()) },
            Inner::Int4RangeArray => &Kind::Array(Type(Inner::Int4Range)),
-            Inner::NumRange => &Kind::Range(Type(Inner::Numeric)),
+            Inner::NumRange => &const { Kind::Range(Inner::Numeric.const_oid()) },
            Inner::NumRangeArray => &Kind::Array(Type(Inner::NumRange)),
-            Inner::TsRange => &Kind::Range(Type(Inner::Timestamp)),
+            Inner::TsRange => &const { Kind::Range(Inner::Timestamp.const_oid()) },
            Inner::TsRangeArray => &Kind::Array(Type(Inner::TsRange)),
-            Inner::TstzRange => &Kind::Range(Type(Inner::Timestamptz)),
+            Inner::TstzRange => &const { Kind::Range(Inner::Timestamptz.const_oid()) },
            Inner::TstzRangeArray => &Kind::Array(Type(Inner::TstzRange)),
-            Inner::DateRange => &Kind::Range(Type(Inner::Date)),
+            Inner::DateRange => &const { Kind::Range(Inner::Date.const_oid()) },
            Inner::DateRangeArray => &Kind::Array(Type(Inner::DateRange)),
-            Inner::Int8Range => &Kind::Range(Type(Inner::Int8)),
+            Inner::Int8Range => &const { Kind::Range(Inner::Int8.const_oid()) },
            Inner::Int8RangeArray => &Kind::Array(Type(Inner::Int8Range)),
            Inner::Jsonpath => &Kind::Simple,
            Inner::JsonpathArray => &Kind::Array(Type(Inner::Jsonpath)),
--- a/libs/proxy/tokio-postgres2/src/client.rs
+++ b/libs/proxy/tokio-postgres2/src/client.rs
@@ -1,14 +1,12 @@
 use std::collections::HashMap;
 use std::fmt;
 use std::net::IpAddr;
-use std::sync::Arc;
 use std::task::{Context, Poll};
 use std::time::Duration;

 use bytes::BytesMut;
 use fallible_iterator::FallibleIterator;
 use futures_util::{TryStreamExt, future, ready};
-use parking_lot::Mutex;
 use postgres_protocol2::message::backend::Message;
 use postgres_protocol2::message::frontend;
 use serde::{Deserialize, Serialize};
@@ -16,29 +14,52 @@ use tokio::sync::mpsc;

 use crate::codec::{BackendMessages, FrontendMessage};
 use crate::config::{Host, SslMode};
-use crate::connection::{Request, RequestMessages};
 use crate::query::RowStream;
 use crate::simple_query::SimpleQueryStream;
 use crate::types::{Oid, Type};
 use crate::{
-    CancelToken, Error, ReadyForQueryStatus, SimpleQueryMessage, Statement, Transaction,
-    TransactionBuilder, query, simple_query,
+    CancelToken, Error, ReadyForQueryStatus, SimpleQueryMessage, Transaction, TransactionBuilder,
+    query, simple_query,
 };

 pub struct Responses {
+    /// new messages from conn
    receiver: mpsc::Receiver<BackendMessages>,
+    /// current batch of messages
    cur: BackendMessages,
+    /// number of total queries sent.
+    waiting: usize,
+    /// number of ReadyForQuery messages received.
+    received: usize,
 }

 impl Responses {
    pub fn poll_next(&mut self, cx: &mut Context<'_>) -> Poll<Result<Message, Error>> {
        loop {
-            match self.cur.next().map_err(Error::parse)? {
-                Some(Message::ErrorResponse(body)) => return Poll::Ready(Err(Error::db(body))),
-                Some(message) => return Poll::Ready(Ok(message)),
-                None => {}
+            // get the next saved message
+            if let Some(message) = self.cur.next().map_err(Error::parse)? {
+                let received = self.received;
+
+                // increase the query head if this is the last message.
+                if let Message::ReadyForQuery(_) = message {
+                    self.received += 1;
+                }
+
+                // check if the client has skipped this query.
+                if received + 1 < self.waiting {
+                    // grab the next message.
+                    continue;
+                }
+
+                // convenience: turn the error messaage into a proper error.
+                let res = match message {
+                    Message::ErrorResponse(body) => Err(Error::db(body)),
+                    message => Ok(message),
+                };
+                return Poll::Ready(res);
            }

+            // get the next batch of messages.
            match ready!(self.receiver.poll_recv(cx)) {
                Some(messages) => self.cur = messages,
                None => return Poll::Ready(Err(Error::closed())),
@@ -55,44 +76,87 @@ impl Responses {
 /// (corresponding to the queries in the [crate::prepare] module).
 #[derive(Default)]
 pub(crate) struct CachedTypeInfo {
-    /// A statement for basic information for a type from its
-    /// OID. Corresponds to [TYPEINFO_QUERY](crate::prepare::TYPEINFO_QUERY) (or its
-    /// fallback).
-    pub(crate) typeinfo: Option<Statement>,
-
    /// Cache of types already looked up.
    pub(crate) types: HashMap<Oid, Type>,
 }

 pub struct InnerClient {
-    sender: mpsc::UnboundedSender<Request>,
+    sender: mpsc::UnboundedSender<FrontendMessage>,
+    responses: Responses,

    /// A buffer to use when writing out postgres commands.
-    buffer: Mutex<BytesMut>,
+    buffer: BytesMut,
 }

 impl InnerClient {
-    pub fn send(&self, messages: RequestMessages) -> Result<Responses, Error> {
-        let (sender, receiver) = mpsc::channel(1);
-        let request = Request { messages, sender };
-        self.sender.send(request).map_err(|_| Error::closed())?;
-
-        Ok(Responses {
-            receiver,
-            cur: BackendMessages::empty(),
-        })
+    pub fn start(&mut self) -> Result<PartialQuery, Error> {
+        self.responses.waiting += 1;
+        Ok(PartialQuery(Some(self)))
    }

-    /// Call the given function with a buffer to be used when writing out
-    /// postgres commands.
-    pub fn with_buf<F, R>(&self, f: F) -> R
+    // pub fn send_with_sync<F>(&mut self, f: F) -> Result<&mut Responses, Error>
+    // where
+    //     F: FnOnce(&mut BytesMut) -> Result<(), Error>,
+    // {
+    //     self.start()?.send_with_sync(f)
+    // }
+
+    pub fn send_simple_query(&mut self, query: &str) -> Result<&mut Responses, Error> {
+        self.responses.waiting += 1;
+
+        self.buffer.clear();
+        // simple queries do not need sync.
+        frontend::query(query, &mut self.buffer).map_err(Error::encode)?;
+        let buf = self.buffer.split().freeze();
+        self.send_message(FrontendMessage::Raw(buf))
+    }
+
+    fn send_message(&mut self, messages: FrontendMessage) -> Result<&mut Responses, Error> {
+        self.sender.send(messages).map_err(|_| Error::closed())?;
+        Ok(&mut self.responses)
+    }
+}
+
+pub struct PartialQuery<'a>(Option<&'a mut InnerClient>);
+
+impl Drop for PartialQuery<'_> {
+    fn drop(&mut self) {
+        if let Some(client) = self.0.take() {
+            client.buffer.clear();
+            frontend::sync(&mut client.buffer);
+            let buf = client.buffer.split().freeze();
+            let _ = client.send_message(FrontendMessage::Raw(buf));
+        }
+    }
+}
+
+impl<'a> PartialQuery<'a> {
+    pub fn send_with_flush<F>(&mut self, f: F) -> Result<&mut Responses, Error>
    where
-        F: FnOnce(&mut BytesMut) -> R,
+        F: FnOnce(&mut BytesMut) -> Result<(), Error>,
    {
-        let mut buffer = self.buffer.lock();
-        let r = f(&mut buffer);
-        buffer.clear();
-        r
+        let client = self.0.as_deref_mut().unwrap();
+
+        client.buffer.clear();
+        f(&mut client.buffer)?;
+        frontend::flush(&mut client.buffer);
+        let buf = client.buffer.split().freeze();
+        client.send_message(FrontendMessage::Raw(buf))
+    }
+
+    pub fn send_with_sync<F>(mut self, f: F) -> Result<&'a mut Responses, Error>
+    where
+        F: FnOnce(&mut BytesMut) -> Result<(), Error>,
+    {
+        let client = self.0.as_deref_mut().unwrap();
+
+        client.buffer.clear();
+        f(&mut client.buffer)?;
+        frontend::sync(&mut client.buffer);
+        let buf = client.buffer.split().freeze();
+        let _ = client.send_message(FrontendMessage::Raw(buf));
+
+        Ok(&mut self.0.take().unwrap().responses)
    }
 }

@@ -109,7 +173,7 @@ pub struct SocketConfig {
 /// The client is one half of what is returned when a connection is established. Users interact with the database
 /// through this client object.
 pub struct Client {
-    inner: Arc<InnerClient>,
+    inner: InnerClient,
    cached_typeinfo: CachedTypeInfo,

    socket_config: SocketConfig,
@@ -120,17 +184,24 @@ pub struct Client {

 impl Client {
    pub(crate) fn new(
-        sender: mpsc::UnboundedSender<Request>,
+        sender: mpsc::UnboundedSender<FrontendMessage>,
+        receiver: mpsc::Receiver<BackendMessages>,
        socket_config: SocketConfig,
        ssl_mode: SslMode,
        process_id: i32,
        secret_key: i32,
    ) -> Client {
        Client {
-            inner: Arc::new(InnerClient {
+            inner: InnerClient {
                sender,
+                responses: Responses {
+                    receiver,
+                    cur: BackendMessages::empty(),
+                    waiting: 0,
+                    received: 0,
+                },
                buffer: Default::default(),
-            }),
+            },
            cached_typeinfo: Default::default(),

            socket_config,
@@ -145,19 +216,29 @@ impl Client {
        self.process_id
    }

-    pub(crate) fn inner(&self) -> &Arc<InnerClient> {
-        &self.inner
+    pub(crate) fn inner_mut(&mut self) -> &mut InnerClient {
+        &mut self.inner
    }

    /// Pass text directly to the Postgres backend to allow it to sort out typing itself and
    /// to save a roundtrip
-    pub async fn query_raw_txt<S, I>(&self, statement: &str, params: I) -> Result<RowStream, Error>
+    pub async fn query_raw_txt<S, I>(
+        &mut self,
+        statement: &str,
+        params: I,
+    ) -> Result<RowStream, Error>
    where
        S: AsRef<str>,
        I: IntoIterator<Item = Option<S>>,
        I::IntoIter: ExactSizeIterator,
    {
-        query::query_txt(&self.inner, statement, params).await
+        query::query_txt(
+            &mut self.inner,
+            &mut self.cached_typeinfo,
+            statement,
+            params,
+        )
+        .await
    }

    /// Executes a sequence of SQL statements using the simple query protocol, returning the resulting rows.
@@ -173,12 +254,15 @@ impl Client {
    /// Prepared statements should be use for any query which contains user-specified data, as they provided the
    /// functionality to safely embed that data in the request. Do not form statements via string concatenation and pass
    /// them to this method!
-    pub async fn simple_query(&self, query: &str) -> Result<Vec<SimpleQueryMessage>, Error> {
+    pub async fn simple_query(&mut self, query: &str) -> Result<Vec<SimpleQueryMessage>, Error> {
        self.simple_query_raw(query).await?.try_collect().await
    }

-    pub(crate) async fn simple_query_raw(&self, query: &str) -> Result<SimpleQueryStream, Error> {
-        simple_query::simple_query(self.inner(), query).await
+    pub(crate) async fn simple_query_raw(
+        &mut self,
+        query: &str,
+    ) -> Result<SimpleQueryStream, Error> {
+        simple_query::simple_query(self.inner_mut(), query).await
    }

    /// Executes a sequence of SQL statements using the simple query protocol.
@@ -191,15 +275,11 @@ impl Client {
    /// Prepared statements should be use for any query which contains user-specified data, as they provided the
    /// functionality to safely embed that data in the request. Do not form statements via string concatenation and pass
    /// them to this method!
-    pub async fn batch_execute(&self, query: &str) -> Result<ReadyForQueryStatus, Error> {
-        simple_query::batch_execute(self.inner(), query).await
+    pub async fn batch_execute(&mut self, query: &str) -> Result<ReadyForQueryStatus, Error> {
+        simple_query::batch_execute(self.inner_mut(), query).await
    }

    pub async fn discard_all(&mut self) -> Result<ReadyForQueryStatus, Error> {
-        // clear the prepared statements that are about to be nuked from the postgres session
-
-        self.cached_typeinfo.typeinfo = None;
-
        self.batch_execute("discard all").await
    }

@@ -208,7 +288,7 @@ impl Client {
    /// The transaction will roll back by default - use the `commit` method to commit it.
    pub async fn transaction(&mut self) -> Result<Transaction<'_>, Error> {
        struct RollbackIfNotDone<'me> {
-            client: &'me Client,
+            client: &'me mut Client,
            done: bool,
        }

@@ -218,14 +298,7 @@ impl Client {
                    return;
                }

-                let buf = self.client.inner().with_buf(|buf| {
-                    frontend::query("ROLLBACK", buf).unwrap();
-                    buf.split().freeze()
-                });
-                let _ = self
-                    .client
-                    .inner()
-                    .send(RequestMessages::Single(FrontendMessage::Raw(buf)));
+                let _ = self.client.inner.send_simple_query("ROLLBACK");
            }
        }

@@ -239,7 +312,7 @@ impl Client {
                client: self,
                done: false,
            };
-            self.batch_execute("BEGIN").await?;
+            cleaner.client.batch_execute("BEGIN").await?;
            cleaner.done = true;
        }

@@ -265,11 +338,6 @@ impl Client {
        }
    }

-    /// Query for type information
-    pub(crate) async fn get_type_inner(&mut self, oid: Oid) -> Result<Type, Error> {
-        crate::prepare::get_type(&self.inner, &mut self.cached_typeinfo, oid).await
-    }
-
    /// Determines if the connection to the server has already closed.
    ///
    /// In that case, all future queries will fail.
--- a/libs/proxy/tokio-postgres2/src/codec.rs
+++ b/libs/proxy/tokio-postgres2/src/codec.rs
@@ -1,21 +1,16 @@
 use std::io;

-use bytes::{Buf, Bytes, BytesMut};
+use bytes::{Bytes, BytesMut};
 use fallible_iterator::FallibleIterator;
 use postgres_protocol2::message::backend;
-use postgres_protocol2::message::frontend::CopyData;
 use tokio_util::codec::{Decoder, Encoder};

 pub enum FrontendMessage {
    Raw(Bytes),
-    CopyData(CopyData<Box<dyn Buf + Send>>),
 }

 pub enum BackendMessage {
-    Normal {
-        messages: BackendMessages,
-        request_complete: bool,
-    },
+    Normal { messages: BackendMessages },
    Async(backend::Message),
 }

@@ -44,7 +39,6 @@ impl Encoder<FrontendMessage> for PostgresCodec {
    fn encode(&mut self, item: FrontendMessage, dst: &mut BytesMut) -> io::Result<()> {
        match item {
            FrontendMessage::Raw(buf) => dst.extend_from_slice(&buf),
-            FrontendMessage::CopyData(data) => data.write(dst),
        }

        Ok(())
@@ -57,7 +51,6 @@ impl Decoder for PostgresCodec {

    fn decode(&mut self, src: &mut BytesMut) -> Result<Option<BackendMessage>, io::Error> {
        let mut idx = 0;
-        let mut request_complete = false;

        while let Some(header) = backend::Header::parse(&src[idx..])? {
            let len = header.len() as usize + 1;
@@ -82,7 +75,6 @@ impl Decoder for PostgresCodec {
            idx += len;

            if header.tag() == backend::READY_FOR_QUERY_TAG {
-                request_complete = true;
                break;
            }
        }
@@ -92,7 +84,6 @@ impl Decoder for PostgresCodec {
        } else {
            Ok(Some(BackendMessage::Normal {
                messages: BackendMessages(src.split_to(idx)),
-                request_complete,
            }))
        }
    }
--- a/libs/proxy/tokio-postgres2/src/connect.rs
+++ b/libs/proxy/tokio-postgres2/src/connect.rs
@@ -59,9 +59,11 @@ where
        connect_timeout: config.connect_timeout,
    };

-    let (sender, receiver) = mpsc::unbounded_channel();
+    let (client_tx, conn_rx) = mpsc::unbounded_channel();
+    let (conn_tx, client_rx) = mpsc::channel(4);
    let client = Client::new(
-        sender,
+        client_tx,
+        client_rx,
        socket_config,
        config.ssl_mode,
        process_id,
@@ -74,7 +76,7 @@ where
        .map(|m| BackendMessage::Async(Message::NoticeResponse(m)))
        .collect();

-    let connection = Connection::new(stream, delayed, parameters, receiver);
+    let connection = Connection::new(stream, delayed, parameters, conn_tx, conn_rx);

    Ok((client, connection))
 }
--- a/libs/proxy/tokio-postgres2/src/connection.rs
+++ b/libs/proxy/tokio-postgres2/src/connection.rs
@@ -4,7 +4,6 @@ use std::pin::Pin;
 use std::task::{Context, Poll};

 use bytes::BytesMut;
-use fallible_iterator::FallibleIterator;
 use futures_util::{Sink, Stream, ready};
 use postgres_protocol2::message::backend::Message;
 use postgres_protocol2::message::frontend;
@@ -19,30 +18,12 @@ use crate::error::DbError;
 use crate::maybe_tls_stream::MaybeTlsStream;
 use crate::{AsyncMessage, Error, Notification};

-pub enum RequestMessages {
-    Single(FrontendMessage),
-}
-
-pub struct Request {
-    pub messages: RequestMessages,
-    pub sender: mpsc::Sender<BackendMessages>,
-}
-
-pub struct Response {
-    sender: PollSender<BackendMessages>,
-}
-
 #[derive(PartialEq, Debug)]
 enum State {
    Active,
    Closing,
 }

-enum WriteReady {
-    Terminating,
-    WaitingOnRead,
-}
-
 /// A connection to a PostgreSQL database.
 ///
 /// This is one half of what is returned when a new connection is established. It performs the actual IO with the
@@ -56,9 +37,11 @@ pub struct Connection<S, T> {
    pub stream: Framed<MaybeTlsStream<S, T>, PostgresCodec>,
    /// HACK: we need this in the Neon Proxy to forward params.
    pub parameters: HashMap<String, String>,
-    receiver: mpsc::UnboundedReceiver<Request>,
+
+    sender: PollSender<BackendMessages>,
+    receiver: mpsc::UnboundedReceiver<FrontendMessage>,
+
    pending_responses: VecDeque<BackendMessage>,
-    responses: VecDeque<Response>,
    state: State,
 }

@@ -71,14 +54,15 @@ where
        stream: Framed<MaybeTlsStream<S, T>, PostgresCodec>,
        pending_responses: VecDeque<BackendMessage>,
        parameters: HashMap<String, String>,
-        receiver: mpsc::UnboundedReceiver<Request>,
+        sender: mpsc::Sender<BackendMessages>,
+        receiver: mpsc::UnboundedReceiver<FrontendMessage>,
    ) -> Connection<S, T> {
        Connection {
            stream,
            parameters,
+            sender: PollSender::new(sender),
            receiver,
            pending_responses,
-            responses: VecDeque::new(),
            state: State::Active,
        }
    }
@@ -110,7 +94,7 @@ where
                }
            };

-            let (mut messages, request_complete) = match message {
+            let messages = match message {
                BackendMessage::Async(Message::NoticeResponse(body)) => {
                    let error = DbError::parse(&mut body.fields()).map_err(Error::parse)?;
                    return Poll::Ready(Ok(AsyncMessage::Notice(error)));
@@ -131,41 +115,19 @@ where
                    continue;
                }
                BackendMessage::Async(_) => unreachable!(),
-                BackendMessage::Normal {
-                    messages,
-                    request_complete,
-                } => (messages, request_complete),
+                BackendMessage::Normal { messages } => messages,
            };

-            let mut response = match self.responses.pop_front() {
-                Some(response) => response,
-                None => match messages.next().map_err(Error::parse)? {
-                    Some(Message::ErrorResponse(error)) => {
-                        return Poll::Ready(Err(Error::db(error)));
-                    }
-                    _ => return Poll::Ready(Err(Error::unexpected_message())),
-                },
-            };
-
-            match response.sender.poll_reserve(cx) {
+            match self.sender.poll_reserve(cx) {
                Poll::Ready(Ok(())) => {
-                    let _ = response.sender.send_item(messages);
-                    if !request_complete {
-                        self.responses.push_front(response);
-                    }
+                    let _ = self.sender.send_item(messages);
                }
                Poll::Ready(Err(_)) => {
-                    // we need to keep paging through the rest of the messages even if the receiver's hung up
-                    if !request_complete {
-                        self.responses.push_front(response);
-                    }
+                    return Poll::Ready(Err(Error::closed()));
                }
                Poll::Pending => {
-                    self.responses.push_front(response);
-                    self.pending_responses.push_back(BackendMessage::Normal {
-                        messages,
-                        request_complete,
-                    });
+                    self.pending_responses
+                        .push_back(BackendMessage::Normal { messages });
                    trace!("poll_read: waiting on sender");
                    return Poll::Pending;
                }
@@ -174,7 +136,7 @@ where
    }

    /// Fetch the next client request and enqueue the response sender.
-    fn poll_request(&mut self, cx: &mut Context<'_>) -> Poll<Option<RequestMessages>> {
+    fn poll_request(&mut self, cx: &mut Context<'_>) -> Poll<Option<FrontendMessage>> {
        if self.receiver.is_closed() {
            return Poll::Ready(None);
        }
@@ -182,10 +144,7 @@ where
        match self.receiver.poll_recv(cx) {
            Poll::Ready(Some(request)) => {
                trace!("polled new request");
-                self.responses.push_back(Response {
-                    sender: PollSender::new(request.sender),
-                });
-                Poll::Ready(Some(request.messages))
+                Poll::Ready(Some(request))
            }
            Poll::Ready(None) => Poll::Ready(None),
            Poll::Pending => Poll::Pending,
@@ -194,7 +153,7 @@ where

    /// Process client requests and write them to the postgres connection, flushing if necessary.
    /// client -> postgres
-    fn poll_write(&mut self, cx: &mut Context<'_>) -> Poll<Result<WriteReady, Error>> {
+    fn poll_write(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Error>> {
        loop {
            if Pin::new(&mut self.stream)
                .poll_ready(cx)
@@ -209,14 +168,14 @@ where

            match self.poll_request(cx) {
                // send the message to postgres
-                Poll::Ready(Some(RequestMessages::Single(request))) => {
+                Poll::Ready(Some(request)) => {
                    Pin::new(&mut self.stream)
                        .start_send(request)
                        .map_err(Error::io)?;
                }
                // No more messages from the client, and no more responses to wait for.
                // Send a terminate message to postgres
-                Poll::Ready(None) if self.responses.is_empty() => {
+                Poll::Ready(None) => {
                    trace!("poll_write: at eof, terminating");
                    let mut request = BytesMut::new();
                    frontend::terminate(&mut request);
@@ -228,16 +187,7 @@ where

                    trace!("poll_write: sent eof, closing");
                    trace!("poll_write: done");
-                    return Poll::Ready(Ok(WriteReady::Terminating));
-                }
-                // No more messages from the client, but there are still some responses to wait for.
-                Poll::Ready(None) => {
-                    trace!(
-                        "poll_write: at eof, pending responses {}",
-                        self.responses.len()
-                    );
-                    ready!(self.poll_flush(cx))?;
-                    return Poll::Ready(Ok(WriteReady::WaitingOnRead));
+                    return Poll::Ready(Ok(()));
                }
                // Still waiting for a message from the client.
                Poll::Pending => {
@@ -298,7 +248,7 @@ where
            // if the state is still active, try read from and write to postgres.
            let message = self.poll_read(cx)?;
            let closing = self.poll_write(cx)?;
-            if let Poll::Ready(WriteReady::Terminating) = closing {
+            if let Poll::Ready(()) = closing {
                self.state = State::Closing;
            }

--- a/libs/proxy/tokio-postgres2/src/error/mod.rs
+++ b/libs/proxy/tokio-postgres2/src/error/mod.rs
@@ -86,6 +86,27 @@ pub struct DbError {
 }

 impl DbError {
+    pub fn new_test_error(code: SqlState, message: String) -> Self {
+        DbError {
+            severity: "ERROR".to_string(),
+            parsed_severity: Some(Severity::Error),
+            code,
+            message,
+            detail: None,
+            hint: None,
+            position: None,
+            where_: None,
+            schema: None,
+            table: None,
+            column: None,
+            datatype: None,
+            constraint: None,
+            file: None,
+            line: None,
+            routine: None,
+        }
+    }
+
    pub(crate) fn parse(fields: &mut ErrorFields<'_>) -> io::Result<DbError> {
        let mut severity = None;
        let mut parsed_severity = None;
--- a/libs/proxy/tokio-postgres2/src/generic_client.rs
+++ b/libs/proxy/tokio-postgres2/src/generic_client.rs
@@ -1,9 +1,6 @@
 #![allow(async_fn_in_trait)]

-use postgres_protocol2::Oid;
-
 use crate::query::RowStream;
-use crate::types::Type;
 use crate::{Client, Error, Transaction};

 mod private {
@@ -15,20 +12,17 @@ mod private {
 /// This trait is "sealed", and cannot be implemented outside of this crate.
 pub trait GenericClient: private::Sealed {
    /// Like `Client::query_raw_txt`.
-    async fn query_raw_txt<S, I>(&self, statement: &str, params: I) -> Result<RowStream, Error>
+    async fn query_raw_txt<S, I>(&mut self, statement: &str, params: I) -> Result<RowStream, Error>
    where
        S: AsRef<str> + Sync + Send,
        I: IntoIterator<Item = Option<S>> + Sync + Send,
        I::IntoIter: ExactSizeIterator + Sync + Send;
-
-    /// Query for type information
-    async fn get_type(&mut self, oid: Oid) -> Result<Type, Error>;
 }

 impl private::Sealed for Client {}

 impl GenericClient for Client {
-    async fn query_raw_txt<S, I>(&self, statement: &str, params: I) -> Result<RowStream, Error>
+    async fn query_raw_txt<S, I>(&mut self, statement: &str, params: I) -> Result<RowStream, Error>
    where
        S: AsRef<str> + Sync + Send,
        I: IntoIterator<Item = Option<S>> + Sync + Send,
@@ -36,17 +30,12 @@ impl GenericClient for Client {
    {
        self.query_raw_txt(statement, params).await
    }
-
-    /// Query for type information
-    async fn get_type(&mut self, oid: Oid) -> Result<Type, Error> {
-        self.get_type_inner(oid).await
-    }
 }

 impl private::Sealed for Transaction<'_> {}

 impl GenericClient for Transaction<'_> {
-    async fn query_raw_txt<S, I>(&self, statement: &str, params: I) -> Result<RowStream, Error>
+    async fn query_raw_txt<S, I>(&mut self, statement: &str, params: I) -> Result<RowStream, Error>
    where
        S: AsRef<str> + Sync + Send,
        I: IntoIterator<Item = Option<S>> + Sync + Send,
@@ -54,9 +43,4 @@ impl GenericClient for Transaction<'_> {
    {
        self.query_raw_txt(statement, params).await
    }
-
-    /// Query for type information
-    async fn get_type(&mut self, oid: Oid) -> Result<Type, Error> {
-        self.client_mut().get_type(oid).await
-    }
 }
--- a/libs/proxy/tokio-postgres2/src/lib.rs
+++ b/libs/proxy/tokio-postgres2/src/lib.rs
@@ -18,7 +18,6 @@ pub use crate::statement::{Column, Statement};
 pub use crate::tls::NoTls;
 pub use crate::transaction::Transaction;
 pub use crate::transaction_builder::{IsolationLevel, TransactionBuilder};
-use crate::types::ToSql;

 /// After executing a query, the connection will be in one of these states
 #[derive(Clone, Copy, Debug, PartialEq)]
@@ -120,9 +119,3 @@ pub enum SimpleQueryMessage {
    /// The number of rows modified or selected is returned.
    CommandComplete(u64),
 }
-
-fn slice_iter<'a>(
-    s: &'a [&'a (dyn ToSql + Sync)],
-) -> impl ExactSizeIterator<Item = &'a (dyn ToSql + Sync)> + 'a {
-    s.iter().map(|s| *s as _)
-}
--- a/libs/proxy/tokio-postgres2/src/prepare.rs
+++ b/libs/proxy/tokio-postgres2/src/prepare.rs
@@ -1,19 +1,14 @@
-use std::future::Future;
-use std::pin::Pin;
-use std::sync::Arc;
-
-use bytes::Bytes;
+use bytes::BytesMut;
 use fallible_iterator::FallibleIterator;
-use futures_util::{TryStreamExt, pin_mut};
-use postgres_protocol2::message::backend::Message;
+use postgres_protocol2::IsNull;
+use postgres_protocol2::message::backend::{Message, RowDescriptionBody};
 use postgres_protocol2::message::frontend;
-use tracing::debug;
+use postgres_protocol2::types::oid_to_sql;
+use postgres_types2::Format;

-use crate::client::{CachedTypeInfo, InnerClient};
-use crate::codec::FrontendMessage;
-use crate::connection::RequestMessages;
+use crate::client::{CachedTypeInfo, PartialQuery, Responses};
 use crate::types::{Kind, Oid, Type};
-use crate::{Column, Error, Statement, query, slice_iter};
+use crate::{Column, Error, Row, Statement};

 pub(crate) const TYPEINFO_QUERY: &str = "\
 SELECT t.typname, t.typtype, t.typelem, r.rngsubtype, t.typbasetype, n.nspname, t.typrelid
@@ -23,22 +18,51 @@ INNER JOIN pg_catalog.pg_namespace n ON t.typnamespace = n.oid
 WHERE t.oid = $1
 ";

+/// we need to make sure we close this prepared statement.
+struct CloseStmt<'a, 'b> {
+    client: Option<&'a mut PartialQuery<'b>>,
+    name: &'static str,
+}
+
+impl<'a> CloseStmt<'a, '_> {
+    fn close(mut self) -> Result<&'a mut Responses, Error> {
+        let client = self.client.take().unwrap();
+        client.send_with_flush(|buf| {
+            frontend::close(b'S', self.name, buf).map_err(Error::encode)?;
+            Ok(())
+        })
+    }
+}
+
+impl Drop for CloseStmt<'_, '_> {
+    fn drop(&mut self) {
+        if let Some(client) = self.client.take() {
+            let _ = client.send_with_flush(|buf| {
+                frontend::close(b'S', self.name, buf).map_err(Error::encode)?;
+                Ok(())
+            });
+        }
+    }
+}
+
 async fn prepare_typecheck(
-    client: &Arc<InnerClient>,
+    client: &mut PartialQuery<'_>,
    name: &'static str,
    query: &str,
-    types: &[Type],
 ) -> Result<Statement, Error> {
-    let buf = encode(client, name, query, types)?;
-    let mut responses = client.send(RequestMessages::Single(FrontendMessage::Raw(buf)))?;
+    let responses = client.send_with_flush(|buf| {
+        frontend::parse(name, query, [], buf).map_err(Error::encode)?;
+        frontend::describe(b'S', name, buf).map_err(Error::encode)?;
+        Ok(())
+    })?;

    match responses.next().await? {
        Message::ParseComplete => {}
        _ => return Err(Error::unexpected_message()),
    }

-    let parameter_description = match responses.next().await? {
-        Message::ParameterDescription(body) => body,
+    match responses.next().await? {
+        Message::ParameterDescription(_) => {}
        _ => return Err(Error::unexpected_message()),
    };

@@ -48,13 +72,6 @@ async fn prepare_typecheck(
        _ => return Err(Error::unexpected_message()),
    };

-    let mut parameters = vec![];
-    let mut it = parameter_description.parameters();
-    while let Some(oid) = it.next().map_err(Error::parse)? {
-        let type_ = Type::from_oid(oid).ok_or_else(Error::unexpected_message)?;
-        parameters.push(type_);
-    }
-
    let mut columns = vec![];
    if let Some(row_description) = row_description {
        let mut it = row_description.fields();
@@ -65,98 +82,168 @@ async fn prepare_typecheck(
        }
    }

-    Ok(Statement::new(client, name, parameters, columns))
+    Ok(Statement::new(name, columns))
 }

-fn encode(client: &InnerClient, name: &str, query: &str, types: &[Type]) -> Result<Bytes, Error> {
-    if types.is_empty() {
-        debug!("preparing query {}: {}", name, query);
-    } else {
-        debug!("preparing query {} with types {:?}: {}", name, types, query);
-    }
-
-    client.with_buf(|buf| {
-        frontend::parse(name, query, types.iter().map(Type::oid), buf).map_err(Error::encode)?;
-        frontend::describe(b'S', name, buf).map_err(Error::encode)?;
-        frontend::sync(buf);
-        Ok(buf.split().freeze())
-    })
-}
-
-pub async fn get_type(
-    client: &Arc<InnerClient>,
-    typecache: &mut CachedTypeInfo,
-    oid: Oid,
-) -> Result<Type, Error> {
+fn try_from_cache(typecache: &CachedTypeInfo, oid: Oid) -> Option<Type> {
    if let Some(type_) = Type::from_oid(oid) {
-        return Ok(type_);
+        return Some(type_);
    }

    if let Some(type_) = typecache.types.get(&oid) {
-        return Ok(type_.clone());
+        return Some(type_.clone());
    };

-    let stmt = typeinfo_statement(client, typecache).await?;
+    None
+}

-    let rows = query::query(client, stmt, slice_iter(&[&oid])).await?;
-    pin_mut!(rows);
+pub async fn parse_row_description(
+    client: &mut PartialQuery<'_>,
+    typecache: &mut CachedTypeInfo,
+    row_description: Option<RowDescriptionBody>,
+) -> Result<Vec<Column>, Error> {
+    let mut columns = vec![];

-    let row = match rows.try_next().await? {
-        Some(row) => row,
-        None => return Err(Error::unexpected_message()),
+    if let Some(row_description) = row_description {
+        let mut it = row_description.fields();
+        while let Some(field) = it.next().map_err(Error::parse)? {
+            let type_ = try_from_cache(typecache, field.type_oid()).unwrap_or(Type::UNKNOWN);
+            let column = Column::new(field.name().to_string(), type_, field);
+            columns.push(column);
+        }
+    }
+
+    let all_known = columns.iter().all(|c| c.type_ != Type::UNKNOWN);
+    if all_known {
+        // all known, return early.
+        return Ok(columns);
+    }
+
+    let typeinfo = "neon_proxy_typeinfo";
+
+    // make sure to close the typeinfo statement before exiting.
+    let mut guard = CloseStmt {
+        name: typeinfo,
+        client: None,
+    };
+    let client = guard.client.insert(client);
+
+    // get the typeinfo statement.
+    let stmt = prepare_typecheck(client, typeinfo, TYPEINFO_QUERY).await?;
+
+    for column in &mut columns {
+        column.type_ = get_type(client, typecache, &stmt, column.type_oid()).await?;
+    }
+
+    // cancel the close guard.
+    let responses = guard.close()?;
+
+    match responses.next().await? {
+        Message::CloseComplete => {}
+        _ => return Err(Error::unexpected_message()),
+    }
+
+    Ok(columns)
+}
+
+async fn get_type(
+    client: &mut PartialQuery<'_>,
+    typecache: &mut CachedTypeInfo,
+    stmt: &Statement,
+    mut oid: Oid,
+) -> Result<Type, Error> {
+    let mut stack = vec![];
+    let mut type_ = loop {
+        if let Some(type_) = try_from_cache(typecache, oid) {
+            break type_;
+        }
+
+        let row = exec(client, stmt, oid).await?;
+        if stack.len() > 8 {
+            return Err(Error::unexpected_message());
+        }
+
+        let name: String = row.try_get(0)?;
+        let type_: i8 = row.try_get(1)?;
+        let elem_oid: Oid = row.try_get(2)?;
+        let rngsubtype: Option<Oid> = row.try_get(3)?;
+        let basetype: Oid = row.try_get(4)?;
+        let schema: String = row.try_get(5)?;
+        let relid: Oid = row.try_get(6)?;
+
+        let kind = if type_ == b'e' as i8 {
+            Kind::Enum
+        } else if type_ == b'p' as i8 {
+            Kind::Pseudo
+        } else if basetype != 0 {
+            Kind::Domain(basetype)
+        } else if elem_oid != 0 {
+            stack.push((name, oid, schema));
+            oid = elem_oid;
+            continue;
+        } else if relid != 0 {
+            Kind::Composite(relid)
+        } else if let Some(rngsubtype) = rngsubtype {
+            Kind::Range(rngsubtype)
+        } else {
+            Kind::Simple
+        };
+
+        let type_ = Type::new(name, oid, kind, schema);
+        typecache.types.insert(oid, type_.clone());
+        break type_;
    };

-    let name: String = row.try_get(0)?;
-    let type_: i8 = row.try_get(1)?;
-    let elem_oid: Oid = row.try_get(2)?;
-    let rngsubtype: Option<Oid> = row.try_get(3)?;
-    let basetype: Oid = row.try_get(4)?;
-    let schema: String = row.try_get(5)?;
-    let relid: Oid = row.try_get(6)?;
-
-    let kind = if type_ == b'e' as i8 {
-        Kind::Enum
-    } else if type_ == b'p' as i8 {
-        Kind::Pseudo
-    } else if basetype != 0 {
-        Kind::Domain(basetype)
-    } else if elem_oid != 0 {
-        let type_ = get_type_rec(client, typecache, elem_oid).await?;
-        Kind::Array(type_)
-    } else if relid != 0 {
-        Kind::Composite(relid)
-    } else if let Some(rngsubtype) = rngsubtype {
-        let type_ = get_type_rec(client, typecache, rngsubtype).await?;
-        Kind::Range(type_)
-    } else {
-        Kind::Simple
-    };
-
-    let type_ = Type::new(name, oid, kind, schema);
-    typecache.types.insert(oid, type_.clone());
+    while let Some((name, oid, schema)) = stack.pop() {
+        type_ = Type::new(name, oid, Kind::Array(type_), schema);
+        typecache.types.insert(oid, type_.clone());
+    }

    Ok(type_)
 }

-fn get_type_rec<'a>(
-    client: &'a Arc<InnerClient>,
-    typecache: &'a mut CachedTypeInfo,
-    oid: Oid,
-) -> Pin<Box<dyn Future<Output = Result<Type, Error>> + Send + 'a>> {
-    Box::pin(get_type(client, typecache, oid))
-}
+/// exec the typeinfo statement returning one row.
+async fn exec(
+    client: &mut PartialQuery<'_>,
+    statement: &Statement,
+    param: Oid,
+) -> Result<Row, Error> {
+    let responses = client.send_with_flush(|buf| {
+        encode_bind(statement, param, "", buf);
+        frontend::execute("", 0, buf).map_err(Error::encode)?;
+        Ok(())
+    })?;

-async fn typeinfo_statement(
-    client: &Arc<InnerClient>,
-    typecache: &mut CachedTypeInfo,
-) -> Result<Statement, Error> {
-    if let Some(stmt) = &typecache.typeinfo {
-        return Ok(stmt.clone());
+    match responses.next().await? {
+        Message::BindComplete => {}
+        _ => return Err(Error::unexpected_message()),
    }

-    let typeinfo = "neon_proxy_typeinfo";
-    let stmt = prepare_typecheck(client, typeinfo, TYPEINFO_QUERY, &[]).await?;
+    let row = match responses.next().await? {
+        Message::DataRow(body) => Row::new(statement.clone(), body, Format::Binary)?,
+        _ => return Err(Error::unexpected_message()),
+    };

-    typecache.typeinfo = Some(stmt.clone());
-    Ok(stmt)
+    match responses.next().await? {
+        Message::CommandComplete(_) => {}
+        _ => return Err(Error::unexpected_message()),
+    };
+
+    Ok(row)
+}
+
+fn encode_bind(statement: &Statement, param: Oid, portal: &str, buf: &mut BytesMut) {
+    frontend::bind(
+        portal,
+        statement.name(),
+        [Format::Binary as i16],
+        [param],
+        |param, buf| {
+            oid_to_sql(param, buf);
+            Ok(IsNull::No)
+        },
+        [Format::Binary as i16],
+        buf,
+    )
+    .unwrap();
 }
--- a/libs/proxy/tokio-postgres2/src/query.rs
+++ b/libs/proxy/tokio-postgres2/src/query.rs
@@ -1,76 +1,43 @@
-use std::fmt;
-use std::marker::PhantomPinned;
 use std::pin::Pin;
-use std::sync::Arc;
 use std::task::{Context, Poll};

-use bytes::{BufMut, Bytes, BytesMut};
-use fallible_iterator::FallibleIterator;
+use bytes::BufMut;
 use futures_util::{Stream, ready};
-use pin_project_lite::pin_project;
 use postgres_protocol2::message::backend::Message;
 use postgres_protocol2::message::frontend;
-use postgres_types2::{Format, ToSql, Type};
-use tracing::debug;
+use postgres_types2::Format;

-use crate::client::{InnerClient, Responses};
-use crate::codec::FrontendMessage;
-use crate::connection::RequestMessages;
-use crate::types::IsNull;
-use crate::{Column, Error, ReadyForQueryStatus, Row, Statement};
+use crate::client::{CachedTypeInfo, InnerClient, Responses};
+use crate::{Error, ReadyForQueryStatus, Row, Statement};

-struct BorrowToSqlParamsDebug<'a>(&'a [&'a (dyn ToSql + Sync)]);
-
-impl fmt::Debug for BorrowToSqlParamsDebug<'_> {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        f.debug_list().entries(self.0.iter()).finish()
-    }
-}
-
-pub async fn query<'a, I>(
-    client: &InnerClient,
-    statement: Statement,
-    params: I,
-) -> Result<RowStream, Error>
-where
-    I: IntoIterator<Item = &'a (dyn ToSql + Sync)>,
-    I::IntoIter: ExactSizeIterator,
-{
-    let buf = if tracing::enabled!(tracing::Level::DEBUG) {
-        let params = params.into_iter().collect::<Vec<_>>();
-        debug!(
-            "executing statement {} with parameters: {:?}",
-            statement.name(),
-            BorrowToSqlParamsDebug(params.as_slice()),
-        );
-        encode(client, &statement, params)?
-    } else {
-        encode(client, &statement, params)?
-    };
-    let responses = start(client, buf).await?;
-    Ok(RowStream {
-        statement,
-        responses,
-        command_tag: None,
-        status: ReadyForQueryStatus::Unknown,
-        output_format: Format::Binary,
-        _p: PhantomPinned,
-    })
-}
-
-pub async fn query_txt<S, I>(
-    client: &Arc<InnerClient>,
+pub async fn query_txt<'a, S, I>(
+    client: &'a mut InnerClient,
+    typecache: &mut CachedTypeInfo,
    query: &str,
    params: I,
-) -> Result<RowStream, Error>
+) -> Result<RowStream<'a>, Error>
 where
    S: AsRef<str>,
    I: IntoIterator<Item = Option<S>>,
    I::IntoIter: ExactSizeIterator,
 {
    let params = params.into_iter();
+    let mut client = client.start()?;

-    let buf = client.with_buf(|buf| {
+    // Flow:
+    // 1. Parse the query
+    // 2. Inspect the row description for OIDs
+    // 3. If there's any OIDs we don't already know about, perform the typeinfo routine
+    // 4. Execute the query
+    // 5. Sync.
+    //
+    // The typeinfo routine:
+    // 1. Parse the typeinfo query
+    // 2. Execute the query on each OID
+    // 3. If the result does not match an OID we know, repeat 2.
+
+    // parse the query and get type info
+    let responses = client.send_with_flush(|buf| {
        frontend::parse(
            "",                 // unnamed prepared statement
            query,              // query to parse
@@ -79,7 +46,30 @@ where
        )
        .map_err(Error::encode)?;
        frontend::describe(b'S', "", buf).map_err(Error::encode)?;
-        // Bind, pass params as text, retrieve as binary
+        Ok(())
+    })?;
+
+    match responses.next().await? {
+        Message::ParseComplete => {}
+        _ => return Err(Error::unexpected_message()),
+    }
+
+    match responses.next().await? {
+        Message::ParameterDescription(_) => {}
+        _ => return Err(Error::unexpected_message()),
+    };
+
+    let row_description = match responses.next().await? {
+        Message::RowDescription(body) => Some(body),
+        Message::NoData => None,
+        _ => return Err(Error::unexpected_message()),
+    };
+
+    let columns =
+        crate::prepare::parse_row_description(&mut client, typecache, row_description).await?;
+
+    let responses = client.send_with_sync(|buf| {
+        // Bind, pass params as text, retrieve as text
        match frontend::bind(
            "",                 // empty string selects the unnamed portal
            "",                 // unnamed prepared statement
@@ -102,173 +92,55 @@ where

        // Execute
        frontend::execute("", 0, buf).map_err(Error::encode)?;
-        // Sync
-        frontend::sync(buf);

-        Ok(buf.split().freeze())
+        Ok(())
    })?;

-    // now read the responses
-    let mut responses = client.send(RequestMessages::Single(FrontendMessage::Raw(buf)))?;
-
-    match responses.next().await? {
-        Message::ParseComplete => {}
-        _ => return Err(Error::unexpected_message()),
-    }
-
-    let parameter_description = match responses.next().await? {
-        Message::ParameterDescription(body) => body,
-        _ => return Err(Error::unexpected_message()),
-    };
-
-    let row_description = match responses.next().await? {
-        Message::RowDescription(body) => Some(body),
-        Message::NoData => None,
-        _ => return Err(Error::unexpected_message()),
-    };
-
    match responses.next().await? {
        Message::BindComplete => {}
        _ => return Err(Error::unexpected_message()),
    }

-    let mut parameters = vec![];
-    let mut it = parameter_description.parameters();
-    while let Some(oid) = it.next().map_err(Error::parse)? {
-        let type_ = Type::from_oid(oid).unwrap_or(Type::UNKNOWN);
-        parameters.push(type_);
-    }
-
-    let mut columns = vec![];
-    if let Some(row_description) = row_description {
-        let mut it = row_description.fields();
-        while let Some(field) = it.next().map_err(Error::parse)? {
-            let type_ = Type::from_oid(field.type_oid()).unwrap_or(Type::UNKNOWN);
-            let column = Column::new(field.name().to_string(), type_, field);
-            columns.push(column);
-        }
-    }
-
    Ok(RowStream {
-        statement: Statement::new_anonymous(parameters, columns),
        responses,
+        statement: Statement::new("", columns),
        command_tag: None,
        status: ReadyForQueryStatus::Unknown,
        output_format: Format::Text,
-        _p: PhantomPinned,
    })
 }

-async fn start(client: &InnerClient, buf: Bytes) -> Result<Responses, Error> {
-    let mut responses = client.send(RequestMessages::Single(FrontendMessage::Raw(buf)))?;
-
-    match responses.next().await? {
-        Message::BindComplete => {}
-        _ => return Err(Error::unexpected_message()),
-    }
-
-    Ok(responses)
+/// A stream of table rows.
+pub struct RowStream<'a> {
+    responses: &'a mut Responses,
+    output_format: Format,
+    pub statement: Statement,
+    pub command_tag: Option<String>,
+    pub status: ReadyForQueryStatus,
 }

-pub fn encode<'a, I>(client: &InnerClient, statement: &Statement, params: I) -> Result<Bytes, Error>
-where
-    I: IntoIterator<Item = &'a (dyn ToSql + Sync)>,
-    I::IntoIter: ExactSizeIterator,
-{
-    client.with_buf(|buf| {
-        encode_bind(statement, params, "", buf)?;
-        frontend::execute("", 0, buf).map_err(Error::encode)?;
-        frontend::sync(buf);
-        Ok(buf.split().freeze())
-    })
-}
-
-pub fn encode_bind<'a, I>(
-    statement: &Statement,
-    params: I,
-    portal: &str,
-    buf: &mut BytesMut,
-) -> Result<(), Error>
-where
-    I: IntoIterator<Item = &'a (dyn ToSql + Sync)>,
-    I::IntoIter: ExactSizeIterator,
-{
-    let param_types = statement.params();
-    let params = params.into_iter();
-
-    assert!(
-        param_types.len() == params.len(),
-        "expected {} parameters but got {}",
-        param_types.len(),
-        params.len()
-    );
-
-    let (param_formats, params): (Vec<_>, Vec<_>) = params
-        .zip(param_types.iter())
-        .map(|(p, ty)| (p.encode_format(ty) as i16, p))
-        .unzip();
-
-    let params = params.into_iter();
-
-    let mut error_idx = 0;
-    let r = frontend::bind(
-        portal,
-        statement.name(),
-        param_formats,
-        params.zip(param_types).enumerate(),
-        |(idx, (param, ty)), buf| match param.to_sql_checked(ty, buf) {
-            Ok(IsNull::No) => Ok(postgres_protocol2::IsNull::No),
-            Ok(IsNull::Yes) => Ok(postgres_protocol2::IsNull::Yes),
-            Err(e) => {
-                error_idx = idx;
-                Err(e)
-            }
-        },
-        Some(1),
-        buf,
-    );
-    match r {
-        Ok(()) => Ok(()),
-        Err(frontend::BindError::Conversion(e)) => Err(Error::to_sql(e, error_idx)),
-        Err(frontend::BindError::Serialization(e)) => Err(Error::encode(e)),
-    }
-}
-
-pin_project! {
-    /// A stream of table rows.
-    pub struct RowStream {
-        statement: Statement,
-        responses: Responses,
-        command_tag: Option<String>,
-        output_format: Format,
-        status: ReadyForQueryStatus,
-        #[pin]
-        _p: PhantomPinned,
-    }
-}
-
-impl Stream for RowStream {
+impl Stream for RowStream<'_> {
    type Item = Result<Row, Error>;

    fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
-        let this = self.project();
+        let this = self.get_mut();
        loop {
            match ready!(this.responses.poll_next(cx)?) {
                Message::DataRow(body) => {
                    return Poll::Ready(Some(Ok(Row::new(
                        this.statement.clone(),
                        body,
-                        *this.output_format,
+                        this.output_format,
                    )?)));
                }
                Message::EmptyQueryResponse | Message::PortalSuspended => {}
                Message::CommandComplete(body) => {
                    if let Ok(tag) = body.tag() {
-                        *this.command_tag = Some(tag.to_string());
+                        this.command_tag = Some(tag.to_string());
                    }
                }
                Message::ReadyForQuery(status) => {
-                    *this.status = status.into();
+                    this.status = status.into();
                    return Poll::Ready(None);
                }
                _ => return Poll::Ready(Some(Err(Error::unexpected_message()))),
@@ -276,24 +148,3 @@ impl Stream for RowStream {
        }
    }
 }
-
-impl RowStream {
-    /// Returns information about the columns of data in the row.
-    pub fn columns(&self) -> &[Column] {
-        self.statement.columns()
-    }
-
-    /// Returns the command tag of this query.
-    ///
-    /// This is only available after the stream has been exhausted.
-    pub fn command_tag(&self) -> Option<String> {
-        self.command_tag.clone()
-    }
-
-    /// Returns if the connection is ready for querying, with the status of the connection.
-    ///
-    /// This might be available only after the stream has been exhausted.
-    pub fn ready_status(&self) -> ReadyForQueryStatus {
-        self.status
-    }
-}
--- a/libs/proxy/tokio-postgres2/src/simple_query.rs
+++ b/libs/proxy/tokio-postgres2/src/simple_query.rs
@@ -1,19 +1,14 @@
-use std::marker::PhantomPinned;
 use std::pin::Pin;
 use std::sync::Arc;
 use std::task::{Context, Poll};

-use bytes::Bytes;
 use fallible_iterator::FallibleIterator;
 use futures_util::{Stream, ready};
 use pin_project_lite::pin_project;
 use postgres_protocol2::message::backend::Message;
-use postgres_protocol2::message::frontend;
 use tracing::debug;

 use crate::client::{InnerClient, Responses};
-use crate::codec::FrontendMessage;
-use crate::connection::RequestMessages;
 use crate::{Error, ReadyForQueryStatus, SimpleQueryMessage, SimpleQueryRow};

 /// Information about a column of a single query row.
@@ -33,28 +28,28 @@ impl SimpleColumn {
    }
 }

-pub async fn simple_query(client: &InnerClient, query: &str) -> Result<SimpleQueryStream, Error> {
+pub async fn simple_query<'a>(
+    client: &'a mut InnerClient,
+    query: &str,
+) -> Result<SimpleQueryStream<'a>, Error> {
    debug!("executing simple query: {}", query);

-    let buf = encode(client, query)?;
-    let responses = client.send(RequestMessages::Single(FrontendMessage::Raw(buf)))?;
+    let responses = client.send_simple_query(query)?;

    Ok(SimpleQueryStream {
        responses,
        columns: None,
        status: ReadyForQueryStatus::Unknown,
-        _p: PhantomPinned,
    })
 }

 pub async fn batch_execute(
-    client: &InnerClient,
+    client: &mut InnerClient,
    query: &str,
 ) -> Result<ReadyForQueryStatus, Error> {
    debug!("executing statement batch: {}", query);

-    let buf = encode(client, query)?;
-    let mut responses = client.send(RequestMessages::Single(FrontendMessage::Raw(buf)))?;
+    let responses = client.send_simple_query(query)?;

    loop {
        match responses.next().await? {
@@ -68,25 +63,16 @@ pub async fn batch_execute(
    }
 }

-pub(crate) fn encode(client: &InnerClient, query: &str) -> Result<Bytes, Error> {
-    client.with_buf(|buf| {
-        frontend::query(query, buf).map_err(Error::encode)?;
-        Ok(buf.split().freeze())
-    })
-}
-
 pin_project! {
    /// A stream of simple query results.
-    pub struct SimpleQueryStream {
-        responses: Responses,
+    pub struct SimpleQueryStream<'a> {
+        responses: &'a mut Responses,
        columns: Option<Arc<[SimpleColumn]>>,
        status: ReadyForQueryStatus,
-        #[pin]
-        _p: PhantomPinned,
    }
 }

-impl SimpleQueryStream {
+impl SimpleQueryStream<'_> {
    /// Returns if the connection is ready for querying, with the status of the connection.
    ///
    /// This might be available only after the stream has been exhausted.
@@ -95,7 +81,7 @@ impl SimpleQueryStream {
    }
 }

-impl Stream for SimpleQueryStream {
+impl Stream for SimpleQueryStream<'_> {
    type Item = Result<SimpleQueryMessage, Error>;

    fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
--- a/libs/proxy/tokio-postgres2/src/statement.rs
+++ b/libs/proxy/tokio-postgres2/src/statement.rs
@@ -1,35 +1,15 @@
 use std::fmt;
-use std::sync::{Arc, Weak};
+use std::sync::Arc;

+use crate::types::Type;
 use postgres_protocol2::Oid;
 use postgres_protocol2::message::backend::Field;
-use postgres_protocol2::message::frontend;
-
-use crate::client::InnerClient;
-use crate::codec::FrontendMessage;
-use crate::connection::RequestMessages;
-use crate::types::Type;

 struct StatementInner {
-    client: Weak<InnerClient>,
    name: &'static str,
-    params: Vec<Type>,
    columns: Vec<Column>,
 }

-impl Drop for StatementInner {
-    fn drop(&mut self) {
-        if let Some(client) = self.client.upgrade() {
-            let buf = client.with_buf(|buf| {
-                frontend::close(b'S', self.name, buf).unwrap();
-                frontend::sync(buf);
-                buf.split().freeze()
-            });
-            let _ = client.send(RequestMessages::Single(FrontendMessage::Raw(buf)));
-        }
-    }
-}
-
 /// A prepared statement.
 ///
 /// Prepared statements can only be used with the connection that created them.
@@ -37,38 +17,14 @@ impl Drop for StatementInner {
 pub struct Statement(Arc<StatementInner>);

 impl Statement {
-    pub(crate) fn new(
-        inner: &Arc<InnerClient>,
-        name: &'static str,
-        params: Vec<Type>,
-        columns: Vec<Column>,
-    ) -> Statement {
-        Statement(Arc::new(StatementInner {
-            client: Arc::downgrade(inner),
-            name,
-            params,
-            columns,
-        }))
-    }
-
-    pub(crate) fn new_anonymous(params: Vec<Type>, columns: Vec<Column>) -> Statement {
-        Statement(Arc::new(StatementInner {
-            client: Weak::new(),
-            name: "<anonymous>",
-            params,
-            columns,
-        }))
+    pub(crate) fn new(name: &'static str, columns: Vec<Column>) -> Statement {
+        Statement(Arc::new(StatementInner { name, columns }))
    }

    pub(crate) fn name(&self) -> &str {
        self.0.name
    }

-    /// Returns the expected types of the statement's parameters.
-    pub fn params(&self) -> &[Type] {
-        &self.0.params
-    }
-
    /// Returns information about the columns returned when the statement is queried.
    pub fn columns(&self) -> &[Column] {
        &self.0.columns
@@ -78,7 +34,7 @@ impl Statement {
 /// Information about a column of a query.
 pub struct Column {
    name: String,
-    type_: Type,
+    pub(crate) type_: Type,

    // raw fields from RowDescription
    table_oid: Oid,
--- a/libs/proxy/tokio-postgres2/src/transaction.rs
+++ b/libs/proxy/tokio-postgres2/src/transaction.rs
@@ -1,7 +1,3 @@
-use postgres_protocol2::message::frontend;
-
-use crate::codec::FrontendMessage;
-use crate::connection::RequestMessages;
 use crate::query::RowStream;
 use crate::{CancelToken, Client, Error, ReadyForQueryStatus};

@@ -20,14 +16,7 @@ impl Drop for Transaction<'_> {
            return;
        }

-        let buf = self.client.inner().with_buf(|buf| {
-            frontend::query("ROLLBACK", buf).unwrap();
-            buf.split().freeze()
-        });
-        let _ = self
-            .client
-            .inner()
-            .send(RequestMessages::Single(FrontendMessage::Raw(buf)));
+        let _ = self.client.inner_mut().send_simple_query("ROLLBACK");
    }
 }

@@ -54,7 +43,11 @@ impl<'a> Transaction<'a> {
    }

    /// Like `Client::query_raw_txt`.
-    pub async fn query_raw_txt<S, I>(&self, statement: &str, params: I) -> Result<RowStream, Error>
+    pub async fn query_raw_txt<S, I>(
+        &mut self,
+        statement: &str,
+        params: I,
+    ) -> Result<RowStream, Error>
    where
        S: AsRef<str>,
        I: IntoIterator<Item = Option<S>>,
--- a/libs/walproposer/src/walproposer.rs
+++ b/libs/walproposer/src/walproposer.rs
@@ -1,6 +1,7 @@
 #![allow(clippy::todo)]

 use std::ffi::CString;
+use std::str::FromStr;

 use postgres_ffi::WAL_SEGMENT_SIZE;
 use utils::id::TenantTimelineId;
@@ -173,6 +174,8 @@ pub struct Config {
    pub ttid: TenantTimelineId,
    /// List of safekeepers in format `host:port`
    pub safekeepers_list: Vec<String>,
+    /// libpq connection info options
+    pub safekeeper_conninfo_options: String,
    /// Safekeeper reconnect timeout in milliseconds
    pub safekeeper_reconnect_timeout: i32,
    /// Safekeeper connection timeout in milliseconds
@@ -202,6 +205,9 @@ impl Wrapper {
            .into_bytes_with_nul();
        assert!(safekeepers_list_vec.len() == safekeepers_list_vec.capacity());
        let safekeepers_list = safekeepers_list_vec.as_mut_ptr() as *mut std::ffi::c_char;
+        let safekeeper_conninfo_options = CString::from_str(&config.safekeeper_conninfo_options)
+            .unwrap()
+            .into_raw();

        let callback_data = Box::into_raw(Box::new(api)) as *mut ::std::os::raw::c_void;

@@ -209,6 +215,7 @@ impl Wrapper {
            neon_tenant,
            neon_timeline,
            safekeepers_list,
+            safekeeper_conninfo_options,
            safekeeper_reconnect_timeout: config.safekeeper_reconnect_timeout,
            safekeeper_connection_timeout: config.safekeeper_connection_timeout,
            wal_segment_size: WAL_SEGMENT_SIZE as i32, // default 16MB
@@ -576,6 +583,7 @@ mod tests {
        let config = crate::walproposer::Config {
            ttid,
            safekeepers_list: vec!["localhost:5000".to_string()],
+            safekeeper_conninfo_options: String::new(),
            safekeeper_reconnect_timeout: 1000,
            safekeeper_connection_timeout: 10000,
            sync_safekeepers: true,
--- a/pageserver/Cargo.toml
+++ b/pageserver/Cargo.toml
@@ -17,49 +17,69 @@ anyhow.workspace = true
 arc-swap.workspace = true
 async-compression.workspace = true
 async-stream.workspace = true
-bit_field.workspace = true
 bincode.workspace = true
+bit_field.workspace = true
 byteorder.workspace = true
 bytes.workspace = true
-camino.workspace = true
 camino-tempfile.workspace = true
+camino.workspace = true
 chrono = { workspace = true, features = ["serde"] }
 clap = { workspace = true, features = ["string"] }
 consumption_metrics.workspace = true
 crc32c.workspace = true
 either.workspace = true
+enum-map.workspace = true
+enumset = { workspace = true, features = ["serde"]}
 fail.workspace = true
 futures.workspace = true
+hashlink.workspace = true
 hex.workspace = true
-humantime.workspace = true
+http-utils.workspace = true
 humantime-serde.workspace = true
+humantime.workspace = true
 hyper0.workspace = true
 itertools.workspace = true
 jsonwebtoken.workspace = true
 md5.workspace = true
+metrics.workspace = true
 nix.workspace = true
-# hack to get the number of worker threads tokio uses
-num_cpus.workspace = true
+num_cpus.workspace = true # hack to get the number of worker threads tokio uses
 num-traits.workspace = true
 once_cell.workspace = true
+pageserver_api.workspace = true
+pageserver_client.workspace = true # for ResponseErrorMessageExt TOOD refactor that
+pageserver_compaction.workspace = true
+pageserver_page_api.workspace = true
+pem.workspace = true
 pin-project-lite.workspace = true
 postgres_backend.workspace = true
+postgres_connection.workspace = true
+postgres_ffi.workspace = true
+postgres_initdb.workspace = true
 postgres-protocol.workspace = true
 postgres-types.workspace = true
-postgres_initdb.workspace = true
+posthog_client_lite.workspace = true
 pprof.workspace = true
+pq_proto.workspace = true
 rand.workspace = true
 range-set-blaze = { version = "0.1.16", features = ["alloc"] }
 regex.workspace = true
+remote_storage.workspace = true
+reqwest.workspace = true
+rpds.workspace = true
 rustls.workspace = true
 scopeguard.workspace = true
 send-future.workspace = true
-serde.workspace = true
 serde_json = { workspace = true, features = ["raw_value"] }
 serde_path_to_error.workspace = true
 serde_with.workspace = true
+serde.workspace = true
+smallvec.workspace = true
+storage_broker.workspace = true
+strum_macros.workspace = true
+strum.workspace = true
 sysinfo.workspace = true
-tokio-tar.workspace = true
+tenant_size_model.workspace = true
 thiserror.workspace = true
 tikv-jemallocator.workspace = true
 tokio = { workspace = true, features = ["process", "sync", "fs", "rt", "io-util", "time"] }
@@ -68,34 +88,18 @@ tokio-io-timeout.workspace = true
 tokio-postgres.workspace = true
 tokio-rustls.workspace = true
 tokio-stream.workspace = true
+tokio-tar.workspace = true
 tokio-util.workspace = true
 toml_edit = { workspace = true, features = [ "serde" ] }
+tonic.workspace = true
+tonic-reflection.workspace = true
 tracing.workspace = true
 tracing-utils.workspace = true
 url.workspace = true
-walkdir.workspace = true
-metrics.workspace = true
-pageserver_api.workspace = true
-pageserver_client.workspace = true # for ResponseErrorMessageExt TOOD refactor that
-pageserver_compaction.workspace = true
-pem.workspace = true
-postgres_connection.workspace = true
-postgres_ffi.workspace = true
-pq_proto.workspace = true
-remote_storage.workspace = true
-storage_broker.workspace = true
-tenant_size_model.workspace = true
-http-utils.workspace = true
 utils.workspace = true
-workspace_hack.workspace = true
-reqwest.workspace = true
-rpds.workspace = true
-enum-map.workspace = true
-enumset = { workspace = true, features = ["serde"]}
-strum.workspace = true
-strum_macros.workspace = true
 wal_decoder.workspace = true
-smallvec.workspace = true
+walkdir.workspace = true
+workspace_hack.workspace = true
 twox-hash.workspace = true

 [target.'cfg(target_os = "linux")'.dependencies]
--- a/pageserver/benches/bench_metrics.rs
+++ b/pageserver/benches/bench_metrics.rs
@@ -264,10 +264,56 @@ mod propagation_of_cached_label_value {
    }
 }

+criterion_group!(histograms, histograms::bench_bucket_scalability);
+mod histograms {
+    use std::time::Instant;
+
+    use criterion::{BenchmarkId, Criterion};
+    use metrics::core::Collector;
+
+    pub fn bench_bucket_scalability(c: &mut Criterion) {
+        let mut g = c.benchmark_group("bucket_scalability");
+
+        for n in [1, 4, 8, 16, 32, 64, 128, 256] {
+            g.bench_with_input(BenchmarkId::new("nbuckets", n), &n, |b, n| {
+                b.iter_custom(|iters| {
+                    let buckets: Vec<f64> = (0..*n).map(|i| i as f64 * 100.0).collect();
+                    let histo = metrics::Histogram::with_opts(
+                        metrics::prometheus::HistogramOpts::new("name", "help")
+                            .buckets(buckets.clone()),
+                    )
+                    .unwrap();
+                    let start = Instant::now();
+                    for i in 0..usize::try_from(iters).unwrap() {
+                        histo.observe(buckets[i % buckets.len()]);
+                    }
+                    let elapsed = start.elapsed();
+                    // self-test
+                    let mfs = histo.collect();
+                    assert_eq!(mfs.len(), 1);
+                    let metrics = mfs[0].get_metric();
+                    assert_eq!(metrics.len(), 1);
+                    let histo = metrics[0].get_histogram();
+                    let buckets = histo.get_bucket();
+                    assert!(
+                        buckets
+                            .iter()
+                            .enumerate()
+                            .all(|(i, b)| b.get_cumulative_count()
+                                >= i as u64 * (iters / buckets.len() as u64))
+                    );
+                    elapsed
+                })
+            });
+        }
+    }
+}
+
 criterion_main!(
    label_values,
    single_metric_multicore_scalability,
-    propagation_of_cached_label_value
+    propagation_of_cached_label_value,
+    histograms,
 );

 /*
@@ -290,6 +336,14 @@ propagation_of_cached_label_value__naive/nthreads/8 time:   [211.50 ns 214.44 ns
 propagation_of_cached_label_value__long_lived_reference_per_thread/nthreads/1 time:   [14.135 ns 14.147 ns 14.160 ns]
 propagation_of_cached_label_value__long_lived_reference_per_thread/nthreads/4 time:   [14.243 ns 14.255 ns 14.268 ns]
 propagation_of_cached_label_value__long_lived_reference_per_thread/nthreads/8 time:   [14.470 ns 14.682 ns 14.895 ns]
+bucket_scalability/nbuckets/1     time:   [30.352 ns 30.353 ns 30.354 ns]
+bucket_scalability/nbuckets/4     time:   [30.464 ns 30.465 ns 30.467 ns]
+bucket_scalability/nbuckets/8     time:   [30.569 ns 30.575 ns 30.584 ns]
+bucket_scalability/nbuckets/16      time:   [30.961 ns 30.965 ns 30.969 ns]
+bucket_scalability/nbuckets/32      time:   [35.691 ns 35.707 ns 35.722 ns]
+bucket_scalability/nbuckets/64      time:   [47.829 ns 47.898 ns 47.974 ns]
+bucket_scalability/nbuckets/128     time:   [73.479 ns 73.512 ns 73.545 ns]
+bucket_scalability/nbuckets/256     time:   [127.92 ns 127.94 ns 127.96 ns]

 Results on an i3en.3xlarge instance

@@ -344,6 +398,14 @@ propagation_of_cached_label_value__naive/nthreads/8     time:   [434.87 ns 456.4
 propagation_of_cached_label_value__long_lived_reference_per_thread/nthreads/1     time:   [3.3767 ns 3.3974 ns 3.4220 ns]
 propagation_of_cached_label_value__long_lived_reference_per_thread/nthreads/4     time:   [3.6105 ns 4.2355 ns 5.1463 ns]
 propagation_of_cached_label_value__long_lived_reference_per_thread/nthreads/8     time:   [4.0889 ns 4.9714 ns 6.0779 ns]
+bucket_scalability/nbuckets/1     time:   [4.8455 ns 4.8542 ns 4.8646 ns]
+bucket_scalability/nbuckets/4     time:   [4.5663 ns 4.5722 ns 4.5787 ns]
+bucket_scalability/nbuckets/8     time:   [4.5531 ns 4.5670 ns 4.5842 ns]
+bucket_scalability/nbuckets/16      time:   [4.6392 ns 4.6524 ns 4.6685 ns]
+bucket_scalability/nbuckets/32      time:   [6.0302 ns 6.0439 ns 6.0589 ns]
+bucket_scalability/nbuckets/64      time:   [10.608 ns 10.644 ns 10.691 ns]
+bucket_scalability/nbuckets/128     time:   [22.178 ns 22.316 ns 22.483 ns]
+bucket_scalability/nbuckets/256     time:   [42.190 ns 42.328 ns 42.492 ns]

 Results on a Hetzner AX102 AMD Ryzen 9 7950X3D 16-Core Processor

@@ -362,5 +424,13 @@ propagation_of_cached_label_value__naive/nthreads/8     time:   [164.24 ns 170.1
 propagation_of_cached_label_value__long_lived_reference_per_thread/nthreads/1     time:   [2.2915 ns 2.2960 ns 2.3012 ns]
 propagation_of_cached_label_value__long_lived_reference_per_thread/nthreads/4     time:   [2.5726 ns 2.6158 ns 2.6624 ns]
 propagation_of_cached_label_value__long_lived_reference_per_thread/nthreads/8     time:   [2.7068 ns 2.8243 ns 2.9824 ns]
+bucket_scalability/nbuckets/1     time:   [6.3998 ns 6.4288 ns 6.4684 ns]
+bucket_scalability/nbuckets/4     time:   [6.3603 ns 6.3620 ns 6.3637 ns]
+bucket_scalability/nbuckets/8     time:   [6.1646 ns 6.1654 ns 6.1667 ns]
+bucket_scalability/nbuckets/16      time:   [6.1341 ns 6.1391 ns 6.1454 ns]
+bucket_scalability/nbuckets/32      time:   [8.2206 ns 8.2254 ns 8.2301 ns]
+bucket_scalability/nbuckets/64      time:   [13.988 ns 13.994 ns 14.000 ns]
+bucket_scalability/nbuckets/128     time:   [28.180 ns 28.216 ns 28.251 ns]
+bucket_scalability/nbuckets/256     time:   [54.914 ns 54.931 ns 54.951 ns]

 */
--- a/pageserver/page_api/Cargo.toml
+++ b/pageserver/page_api/Cargo.toml
@@ -0,0 +1,19 @@
+[package]
+name = "pageserver_page_api"
+version = "0.1.0"
+edition.workspace = true
+license.workspace = true
+
+[dependencies]
+bytes.workspace = true
+pageserver_api.workspace = true
+postgres_ffi.workspace = true
+prost.workspace = true
+smallvec.workspace = true
+thiserror.workspace = true
+tonic.workspace = true
+utils.workspace = true
+workspace_hack.workspace = true
+
+[build-dependencies]
+tonic-build.workspace = true
--- a/pageserver/page_api/build.rs
+++ b/pageserver/page_api/build.rs
@@ -0,0 +1,13 @@
+use std::env;
+use std::path::PathBuf;
+
+/// Generates Rust code from .proto Protobuf schemas, along with a binary file
+/// descriptor set for Protobuf schema reflection.
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let out_dir = PathBuf::from(env::var("OUT_DIR")?);
+    tonic_build::configure()
+        .bytes(["."])
+        .file_descriptor_set_path(out_dir.join("page_api_descriptor.bin"))
+        .compile_protos(&["proto/page_service.proto"], &["proto"])
+        .map_err(|err| err.into())
+}
--- a/pageserver/page_api/proto/page_service.proto
+++ b/pageserver/page_api/proto/page_service.proto
@@ -0,0 +1,239 @@
+// Page service, presented by pageservers for computes.
+//
+// This is the compute read path. It primarily serves page versions at given
+// LSNs, but also base backups, SLRU segments, and relation metadata.
+//
+// EXPERIMENTAL: this is still under development and subject to change.
+//
+// Request metadata headers:
+// - authorization: JWT token ("Bearer <token>"), if auth is enabled
+// - neon-tenant-id: tenant ID ("7c4a1f9e3bd6470c8f3e21a65bd2e980")
+// - neon-shard-id: shard ID, as <number><count> in hex ("0b10" = shard 11 of 16, 0-based)
+// - neon-timeline-id: timeline ID ("f08c4e9a2d5f76b1e3a7c2d8910f4b3e")
+//
+// The service can be accessed via e.g. grpcurl:
+//
+//    ```
+//    grpcurl \
+//      -plaintext \
+//      -H "neon-tenant-id: 7c4a1f9e3bd6470c8f3e21a65bd2e980" \
+//      -H "neon-shard-id: 0b10" \
+//      -H "neon-timeline-id: f08c4e9a2d5f76b1e3a7c2d8910f4b3e" \
+//      -H "authorization: Bearer $JWT" \
+//      -d '{"read_lsn": {"request_lsn": 1234567890}, "rel": {"spc_oid": 1663, "db_oid": 1234, "rel_number": 5678, "fork_number": 0}}'
+//      localhost:51051 page_api.PageService/CheckRelExists
+//    ```
+//
+// TODO: consider adding neon-compute-mode ("primary", "static", "replica").
+// However, this will require reconnecting when changing modes.
+//
+// TODO: write implementation guidance on
+// - Health checks
+// - Tracing, OpenTelemetry
+// - Compression
+
+syntax = "proto3";
+package page_api;
+
+service PageService {
+  // Returns whether a relation exists.
+  rpc CheckRelExists(CheckRelExistsRequest) returns (CheckRelExistsResponse);
+
+  // Fetches a base backup.
+  rpc GetBaseBackup (GetBaseBackupRequest) returns (stream GetBaseBackupResponseChunk);
+
+  // Returns the total size of a database, as # of bytes.
+  rpc GetDbSize (GetDbSizeRequest) returns (GetDbSizeResponse);
+
+  // Fetches pages.
+  //
+  // This is implemented as a bidirectional streaming RPC for performance. Unary
+  // requests incur costs for e.g. HTTP/2 stream setup, header parsing,
+  // authentication, and so on -- with streaming, we only pay these costs during
+  // the initial stream setup. This ~doubles throughput in benchmarks. Other
+  // RPCs use regular unary requests, since they are not as frequent and
+  // performance-critical, and this simplifies implementation.
+  //
+  // NB: a gRPC status response (e.g. errors) will terminate the stream. The
+  // stream may be shared by multiple Postgres backends, so we avoid this by
+  // sending them as GetPageResponse.status_code instead.
+  rpc GetPages (stream GetPageRequest) returns (stream GetPageResponse);
+
+  // Returns the size of a relation, as # of blocks.
+  rpc GetRelSize (GetRelSizeRequest) returns (GetRelSizeResponse);
+
+  // Fetches an SLRU segment.
+  rpc GetSlruSegment (GetSlruSegmentRequest) returns (GetSlruSegmentResponse);
+}
+
+// The LSN a request should read at.
+message ReadLsn {
+  // The request's read LSN. Required.
+  uint64 request_lsn = 1;
+  // If given, the caller guarantees that the page has not been modified since
+  // this LSN. Must be smaller than or equal to request_lsn. This allows the
+  // Pageserver to serve an old page without waiting for the request LSN to
+  // arrive. Valid for all request types.
+  //
+  // It is undefined behaviour to make a request such that the page was, in
+  // fact, modified between request_lsn and not_modified_since_lsn. The
+  // Pageserver might detect it and return an error, or it might return the old
+  // page version or the new page version. Setting not_modified_since_lsn equal
+  // to request_lsn is always safe, but can lead to unnecessary waiting.
+  uint64 not_modified_since_lsn = 2;
+}
+
+// A relation identifier.
+message RelTag {
+    uint32 spc_oid = 1;
+    uint32 db_oid = 2;
+    uint32 rel_number = 3;
+    uint32 fork_number = 4;
+}
+
+// Checks whether a relation exists, at the given LSN. Only valid on shard 0,
+// other shards will error.
+message CheckRelExistsRequest {
+  ReadLsn read_lsn = 1;
+  RelTag rel = 2;
+}
+
+message CheckRelExistsResponse {
+  bool exists = 1;
+}
+
+// Requests a base backup at a given LSN.
+message GetBaseBackupRequest {
+  // The LSN to fetch a base backup at.
+  ReadLsn read_lsn = 1;
+  // If true, logical replication slots will not be created.
+  bool replica = 2;
+}
+
+// Base backup response chunk, returned as an ordered stream.
+message GetBaseBackupResponseChunk {
+  // A basebackup data chunk. The size is undefined, but bounded by the 4 MB
+  // gRPC message size limit.
+  bytes chunk = 1;
+}
+
+// Requests the size of a database, as # of bytes. Only valid on shard 0, other
+// shards will error.
+message GetDbSizeRequest {
+  ReadLsn read_lsn = 1;
+  uint32 db_oid = 2;
+}
+
+message GetDbSizeResponse {
+  uint64 num_bytes = 1;
+}
+
+// Requests one or more pages.
+message GetPageRequest {
+  // A request ID. Will be included in the response. Should be unique for
+  // in-flight requests on the stream.
+  uint64 request_id = 1;
+  // The request class.
+  GetPageClass request_class = 2;
+  // The LSN to read at.
+  ReadLsn read_lsn = 3;
+  // The relation to read from.
+  RelTag rel = 4;
+  // Page numbers to read. Must belong to the remote shard.
+  //
+  // Multiple pages will be executed as a single batch by the Pageserver,
+  // amortizing layer access costs and parallelizing them. This may increase the
+  // latency of any individual request, but improves the overall latency and
+  // throughput of the batch as a whole.
+  //
+  // TODO: this causes an allocation in the common single-block case. The sender
+  // can use a SmallVec to stack-allocate it, but Prost will always deserialize
+  // into a heap-allocated Vec. Consider optimizing this.
+  //
+  // TODO: we might be able to avoid a sort or something if we mandate that these
+  // are always in order. But we can't currenly rely on this on the server, because
+  // of compatibility with the libpq protocol handler.
+  repeated uint32 block_number = 5;
+}
+
+// A GetPageRequest class. Primarily intended for observability, but may also be
+// used for prioritization in the future.
+enum GetPageClass {
+  // Unknown class. For backwards compatibility: used when an older client version sends a class
+  // that a newer server version has removed.
+  GET_PAGE_CLASS_UNKNOWN = 0;
+  // A normal request. This is the default.
+  GET_PAGE_CLASS_NORMAL = 1;
+  // A prefetch request. NB: can only be classified on pg < 18.
+  GET_PAGE_CLASS_PREFETCH = 2;
+  // A background request (e.g. vacuum).
+  GET_PAGE_CLASS_BACKGROUND = 3;
+}
+
+// A GetPage response.
+//
+// A batch response will contain all of the requested pages. We could eagerly
+// emit individual pages as soon as they are ready, but on a readv() Postgres
+// holds buffer pool locks on all pages in the batch and we'll only return once
+// the entire batch is ready, so no one can make use of the individual pages.
+message GetPageResponse {
+  // The original request's ID.
+  uint64 request_id = 1;
+  // The response status code.
+  GetPageStatusCode status_code = 2;
+  // A string describing the status, if any.
+  string reason = 3;
+  // The 8KB page images, in the same order as the request. Empty if status_code != OK.
+  repeated bytes page_image = 4;
+}
+
+// A GetPageResponse status code.
+//
+// These are effectively equivalent to gRPC statuses. However, we use a bidirectional stream
+// (potentially shared by many backends), and a gRPC status response would terminate the stream so
+// we send GetPageResponse messages with these codes instead.
+enum GetPageStatusCode {
+  // Unknown status. For forwards compatibility: used when an older client version receives a new
+  // status code from a newer server version.
+  GET_PAGE_STATUS_CODE_UNKNOWN = 0;
+  // The request was successful.
+  GET_PAGE_STATUS_CODE_OK = 1;
+  // The page did not exist. The tenant/timeline/shard has already been
+  // validated during stream setup.
+  GET_PAGE_STATUS_CODE_NOT_FOUND = 2;
+  // The request was invalid.
+  GET_PAGE_STATUS_CODE_INVALID_REQUEST = 3;
+  // The request failed due to an internal server error.
+  GET_PAGE_STATUS_CODE_INTERNAL_ERROR = 4;
+  // The tenant is rate limited. Slow down and retry later.
+  GET_PAGE_STATUS_CODE_SLOW_DOWN = 5;
+  // NB: shutdown errors are emitted as a gRPC Unavailable status.
+  //
+  // TODO: consider adding a GET_PAGE_STATUS_CODE_LAYER_DOWNLOAD in the case of a layer download.
+  // This could free up the server task to process other requests while the download is in progress.
+}
+
+// Fetches the size of a relation at a given LSN, as # of blocks. Only valid on
+// shard 0, other shards will error.
+message GetRelSizeRequest {
+  ReadLsn read_lsn = 1;
+  RelTag rel = 2;
+}
+
+message GetRelSizeResponse {
+  uint32 num_blocks = 1;
+}
+
+// Requests an SLRU segment. Only valid on shard 0, other shards will error.
+message GetSlruSegmentRequest {
+  ReadLsn read_lsn = 1;
+  uint32 kind = 2;
+  uint32 segno = 3;
+}
+
+// Returns an SLRU segment.
+//
+// These are up 32 pages (256 KB), so we can send them as a single response.
+message GetSlruSegmentResponse {
+  bytes segment = 1;
+}
--- a/pageserver/page_api/src/lib.rs
+++ b/pageserver/page_api/src/lib.rs
@@ -0,0 +1,23 @@
+//! This crate provides the Pageserver's page API. It contains:
+//!
+//! * proto/page_service.proto: the Protobuf schema for the page API.
+//! * proto: auto-generated Protobuf types for gRPC.
+//!
+//! This crate is used by both the client and the server. Try to keep it slim.
+
+// Code generated by protobuf.
+pub mod proto {
+    tonic::include_proto!("page_api");
+
+    /// File descriptor set for Protobuf schema reflection. This allows using
+    /// e.g. grpcurl with the API.
+    pub const FILE_DESCRIPTOR_SET: &[u8] =
+        tonic::include_file_descriptor_set!("page_api_descriptor");
+
+    pub use page_service_client::PageServiceClient;
+    pub use page_service_server::{PageService, PageServiceServer};
+}
+
+mod model;
+
+pub use model::*;
--- a/pageserver/page_api/src/model.rs
+++ b/pageserver/page_api/src/model.rs
@@ -0,0 +1,595 @@
+//! Structs representing the canonical page service API.
+//!
+//! These mirror the autogenerated Protobuf types. The differences are:
+//!
+//! - Types that are in fact required by the API are not Options. The protobuf "required"
+//!   attribute is deprecated and 'prost' marks a lot of members as optional because of that.
+//!   (See <https://github.com/tokio-rs/prost/issues/800> for a gripe on this)
+//!
+//! - Use more precise datatypes, e.g. Lsn and uints shorter than 32 bits.
+//!
+//! - Validate protocol invariants, via try_from() and try_into().
+
+use bytes::Bytes;
+use postgres_ffi::Oid;
+use smallvec::SmallVec;
+// TODO: split out Lsn, RelTag, SlruKind, Oid and other basic types to a separate crate, to avoid
+// pulling in all of their other crate dependencies when building the client.
+use utils::lsn::Lsn;
+
+use crate::proto;
+
+/// A protocol error. Typically returned via try_from() or try_into().
+#[derive(thiserror::Error, Debug)]
+pub enum ProtocolError {
+    #[error("field '{0}' has invalid value '{1}'")]
+    Invalid(&'static str, String),
+    #[error("required field '{0}' is missing")]
+    Missing(&'static str),
+}
+
+impl ProtocolError {
+    /// Helper to generate a new ProtocolError::Invalid for the given field and value.
+    pub fn invalid(field: &'static str, value: impl std::fmt::Debug) -> Self {
+        Self::Invalid(field, format!("{value:?}"))
+    }
+}
+
+impl From<ProtocolError> for tonic::Status {
+    fn from(err: ProtocolError) -> Self {
+        tonic::Status::invalid_argument(format!("{err}"))
+    }
+}
+
+/// The LSN a request should read at.
+#[derive(Clone, Copy, Debug)]
+pub struct ReadLsn {
+    /// The request's read LSN.
+    pub request_lsn: Lsn,
+    /// If given, the caller guarantees that the page has not been modified since this LSN. Must be
+    /// smaller than or equal to request_lsn. This allows the Pageserver to serve an old page
+    /// without waiting for the request LSN to arrive. Valid for all request types.
+    ///
+    /// It is undefined behaviour to make a request such that the page was, in fact, modified
+    /// between request_lsn and not_modified_since_lsn. The Pageserver might detect it and return an
+    /// error, or it might return the old page version or the new page version. Setting
+    /// not_modified_since_lsn equal to request_lsn is always safe, but can lead to unnecessary
+    /// waiting.
+    pub not_modified_since_lsn: Option<Lsn>,
+}
+
+impl ReadLsn {
+    /// Validates the ReadLsn.
+    pub fn validate(&self) -> Result<(), ProtocolError> {
+        if self.request_lsn == Lsn::INVALID {
+            return Err(ProtocolError::invalid("request_lsn", self.request_lsn));
+        }
+        if self.not_modified_since_lsn > Some(self.request_lsn) {
+            return Err(ProtocolError::invalid(
+                "not_modified_since_lsn",
+                self.not_modified_since_lsn,
+            ));
+        }
+        Ok(())
+    }
+}
+
+impl TryFrom<proto::ReadLsn> for ReadLsn {
+    type Error = ProtocolError;
+
+    fn try_from(pb: proto::ReadLsn) -> Result<Self, Self::Error> {
+        let read_lsn = Self {
+            request_lsn: Lsn(pb.request_lsn),
+            not_modified_since_lsn: match pb.not_modified_since_lsn {
+                0 => None,
+                lsn => Some(Lsn(lsn)),
+            },
+        };
+        read_lsn.validate()?;
+        Ok(read_lsn)
+    }
+}
+
+impl TryFrom<ReadLsn> for proto::ReadLsn {
+    type Error = ProtocolError;
+
+    fn try_from(read_lsn: ReadLsn) -> Result<Self, Self::Error> {
+        read_lsn.validate()?;
+        Ok(Self {
+            request_lsn: read_lsn.request_lsn.0,
+            not_modified_since_lsn: read_lsn.not_modified_since_lsn.unwrap_or_default().0,
+        })
+    }
+}
+
+// RelTag is defined in pageserver_api::reltag.
+pub type RelTag = pageserver_api::reltag::RelTag;
+
+impl TryFrom<proto::RelTag> for RelTag {
+    type Error = ProtocolError;
+
+    fn try_from(pb: proto::RelTag) -> Result<Self, Self::Error> {
+        Ok(Self {
+            spcnode: pb.spc_oid,
+            dbnode: pb.db_oid,
+            relnode: pb.rel_number,
+            forknum: pb
+                .fork_number
+                .try_into()
+                .map_err(|_| ProtocolError::invalid("fork_number", pb.fork_number))?,
+        })
+    }
+}
+
+impl From<RelTag> for proto::RelTag {
+    fn from(rel_tag: RelTag) -> Self {
+        Self {
+            spc_oid: rel_tag.spcnode,
+            db_oid: rel_tag.dbnode,
+            rel_number: rel_tag.relnode,
+            fork_number: rel_tag.forknum as u32,
+        }
+    }
+}
+
+/// Checks whether a relation exists, at the given LSN. Only valid on shard 0, other shards error.
+#[derive(Clone, Copy, Debug)]
+pub struct CheckRelExistsRequest {
+    pub read_lsn: ReadLsn,
+    pub rel: RelTag,
+}
+
+impl TryFrom<proto::CheckRelExistsRequest> for CheckRelExistsRequest {
+    type Error = ProtocolError;
+
+    fn try_from(pb: proto::CheckRelExistsRequest) -> Result<Self, Self::Error> {
+        Ok(Self {
+            read_lsn: pb
+                .read_lsn
+                .ok_or(ProtocolError::Missing("read_lsn"))?
+                .try_into()?,
+            rel: pb.rel.ok_or(ProtocolError::Missing("rel"))?.try_into()?,
+        })
+    }
+}
+
+pub type CheckRelExistsResponse = bool;
+
+impl From<proto::CheckRelExistsResponse> for CheckRelExistsResponse {
+    fn from(pb: proto::CheckRelExistsResponse) -> Self {
+        pb.exists
+    }
+}
+
+impl From<CheckRelExistsResponse> for proto::CheckRelExistsResponse {
+    fn from(exists: CheckRelExistsResponse) -> Self {
+        Self { exists }
+    }
+}
+
+/// Requests a base backup at a given LSN.
+#[derive(Clone, Copy, Debug)]
+pub struct GetBaseBackupRequest {
+    /// The LSN to fetch a base backup at.
+    pub read_lsn: ReadLsn,
+    /// If true, logical replication slots will not be created.
+    pub replica: bool,
+}
+
+impl TryFrom<proto::GetBaseBackupRequest> for GetBaseBackupRequest {
+    type Error = ProtocolError;
+
+    fn try_from(pb: proto::GetBaseBackupRequest) -> Result<Self, Self::Error> {
+        Ok(Self {
+            read_lsn: pb
+                .read_lsn
+                .ok_or(ProtocolError::Missing("read_lsn"))?
+                .try_into()?,
+            replica: pb.replica,
+        })
+    }
+}
+
+impl TryFrom<GetBaseBackupRequest> for proto::GetBaseBackupRequest {
+    type Error = ProtocolError;
+
+    fn try_from(request: GetBaseBackupRequest) -> Result<Self, Self::Error> {
+        Ok(Self {
+            read_lsn: Some(request.read_lsn.try_into()?),
+            replica: request.replica,
+        })
+    }
+}
+
+pub type GetBaseBackupResponseChunk = Bytes;
+
+impl TryFrom<proto::GetBaseBackupResponseChunk> for GetBaseBackupResponseChunk {
+    type Error = ProtocolError;
+
+    fn try_from(pb: proto::GetBaseBackupResponseChunk) -> Result<Self, Self::Error> {
+        if pb.chunk.is_empty() {
+            return Err(ProtocolError::Missing("chunk"));
+        }
+        Ok(pb.chunk)
+    }
+}
+
+impl TryFrom<GetBaseBackupResponseChunk> for proto::GetBaseBackupResponseChunk {
+    type Error = ProtocolError;
+
+    fn try_from(chunk: GetBaseBackupResponseChunk) -> Result<Self, Self::Error> {
+        if chunk.is_empty() {
+            return Err(ProtocolError::Missing("chunk"));
+        }
+        Ok(Self { chunk })
+    }
+}
+
+/// Requests the size of a database, as # of bytes. Only valid on shard 0, other shards will error.
+#[derive(Clone, Copy, Debug)]
+pub struct GetDbSizeRequest {
+    pub read_lsn: ReadLsn,
+    pub db_oid: Oid,
+}
+
+impl TryFrom<proto::GetDbSizeRequest> for GetDbSizeRequest {
+    type Error = ProtocolError;
+
+    fn try_from(pb: proto::GetDbSizeRequest) -> Result<Self, Self::Error> {
+        Ok(Self {
+            read_lsn: pb
+                .read_lsn
+                .ok_or(ProtocolError::Missing("read_lsn"))?
+                .try_into()?,
+            db_oid: pb.db_oid,
+        })
+    }
+}
+
+impl TryFrom<GetDbSizeRequest> for proto::GetDbSizeRequest {
+    type Error = ProtocolError;
+
+    fn try_from(request: GetDbSizeRequest) -> Result<Self, Self::Error> {
+        Ok(Self {
+            read_lsn: Some(request.read_lsn.try_into()?),
+            db_oid: request.db_oid,
+        })
+    }
+}
+
+pub type GetDbSizeResponse = u64;
+
+impl From<proto::GetDbSizeResponse> for GetDbSizeResponse {
+    fn from(pb: proto::GetDbSizeResponse) -> Self {
+        pb.num_bytes
+    }
+}
+
+impl From<GetDbSizeResponse> for proto::GetDbSizeResponse {
+    fn from(num_bytes: GetDbSizeResponse) -> Self {
+        Self { num_bytes }
+    }
+}
+
+/// Requests one or more pages.
+#[derive(Clone, Debug)]
+pub struct GetPageRequest {
+    /// A request ID. Will be included in the response. Should be unique for in-flight requests on
+    /// the stream.
+    pub request_id: RequestID,
+    /// The request class.
+    pub request_class: GetPageClass,
+    /// The LSN to read at.
+    pub read_lsn: ReadLsn,
+    /// The relation to read from.
+    pub rel: RelTag,
+    /// Page numbers to read. Must belong to the remote shard.
+    ///
+    /// Multiple pages will be executed as a single batch by the Pageserver, amortizing layer access
+    /// costs and parallelizing them. This may increase the latency of any individual request, but
+    /// improves the overall latency and throughput of the batch as a whole.
+    pub block_numbers: SmallVec<[u32; 1]>,
+}
+
+impl TryFrom<proto::GetPageRequest> for GetPageRequest {
+    type Error = ProtocolError;
+
+    fn try_from(pb: proto::GetPageRequest) -> Result<Self, Self::Error> {
+        if pb.block_number.is_empty() {
+            return Err(ProtocolError::Missing("block_number"));
+        }
+        Ok(Self {
+            request_id: pb.request_id,
+            request_class: pb.request_class.into(),
+            read_lsn: pb
+                .read_lsn
+                .ok_or(ProtocolError::Missing("read_lsn"))?
+                .try_into()?,
+            rel: pb.rel.ok_or(ProtocolError::Missing("rel"))?.try_into()?,
+            block_numbers: pb.block_number.into(),
+        })
+    }
+}
+
+impl TryFrom<GetPageRequest> for proto::GetPageRequest {
+    type Error = ProtocolError;
+
+    fn try_from(request: GetPageRequest) -> Result<Self, Self::Error> {
+        if request.block_numbers.is_empty() {
+            return Err(ProtocolError::Missing("block_number"));
+        }
+        Ok(Self {
+            request_id: request.request_id,
+            request_class: request.request_class.into(),
+            read_lsn: Some(request.read_lsn.try_into()?),
+            rel: Some(request.rel.into()),
+            block_number: request.block_numbers.into_vec(),
+        })
+    }
+}
+
+/// A GetPage request ID.
+pub type RequestID = u64;
+
+/// A GetPage request class.
+#[derive(Clone, Copy, Debug)]
+pub enum GetPageClass {
+    /// Unknown class. For backwards compatibility: used when an older client version sends a class
+    /// that a newer server version has removed.
+    Unknown,
+    /// A normal request. This is the default.
+    Normal,
+    /// A prefetch request. NB: can only be classified on pg < 18.
+    Prefetch,
+    /// A background request (e.g. vacuum).
+    Background,
+}
+
+impl From<proto::GetPageClass> for GetPageClass {
+    fn from(pb: proto::GetPageClass) -> Self {
+        match pb {
+            proto::GetPageClass::Unknown => Self::Unknown,
+            proto::GetPageClass::Normal => Self::Normal,
+            proto::GetPageClass::Prefetch => Self::Prefetch,
+            proto::GetPageClass::Background => Self::Background,
+        }
+    }
+}
+
+impl From<i32> for GetPageClass {
+    fn from(class: i32) -> Self {
+        proto::GetPageClass::try_from(class)
+            .unwrap_or(proto::GetPageClass::Unknown)
+            .into()
+    }
+}
+
+impl From<GetPageClass> for proto::GetPageClass {
+    fn from(class: GetPageClass) -> Self {
+        match class {
+            GetPageClass::Unknown => Self::Unknown,
+            GetPageClass::Normal => Self::Normal,
+            GetPageClass::Prefetch => Self::Prefetch,
+            GetPageClass::Background => Self::Background,
+        }
+    }
+}
+
+impl From<GetPageClass> for i32 {
+    fn from(class: GetPageClass) -> Self {
+        proto::GetPageClass::from(class).into()
+    }
+}
+
+/// A GetPage response.
+///
+/// A batch response will contain all of the requested pages. We could eagerly emit individual pages
+/// as soon as they are ready, but on a readv() Postgres holds buffer pool locks on all pages in the
+/// batch and we'll only return once the entire batch is ready, so no one can make use of the
+/// individual pages.
+#[derive(Clone, Debug)]
+pub struct GetPageResponse {
+    /// The original request's ID.
+    pub request_id: RequestID,
+    /// The response status code.
+    pub status_code: GetPageStatusCode,
+    /// A string describing the status, if any.
+    pub reason: Option<String>,
+    /// The 8KB page images, in the same order as the request. Empty if status != OK.
+    pub page_images: SmallVec<[Bytes; 1]>,
+}
+
+impl From<proto::GetPageResponse> for GetPageResponse {
+    fn from(pb: proto::GetPageResponse) -> Self {
+        Self {
+            request_id: pb.request_id,
+            status_code: pb.status_code.into(),
+            reason: Some(pb.reason).filter(|r| !r.is_empty()),
+            page_images: pb.page_image.into(),
+        }
+    }
+}
+
+impl From<GetPageResponse> for proto::GetPageResponse {
+    fn from(response: GetPageResponse) -> Self {
+        Self {
+            request_id: response.request_id,
+            status_code: response.status_code.into(),
+            reason: response.reason.unwrap_or_default(),
+            page_image: response.page_images.into_vec(),
+        }
+    }
+}
+
+/// A GetPage response status code.
+///
+/// These are effectively equivalent to gRPC statuses. However, we use a bidirectional stream
+/// (potentially shared by many backends), and a gRPC status response would terminate the stream so
+/// we send GetPageResponse messages with these codes instead.
+#[derive(Clone, Copy, Debug)]
+pub enum GetPageStatusCode {
+    /// Unknown status. For forwards compatibility: used when an older client version receives a new
+    /// status code from a newer server version.
+    Unknown,
+    /// The request was successful.
+    Ok,
+    /// The page did not exist. The tenant/timeline/shard has already been validated during stream
+    /// setup.
+    NotFound,
+    /// The request was invalid.
+    InvalidRequest,
+    /// The request failed due to an internal server error.
+    InternalError,
+    /// The tenant is rate limited. Slow down and retry later.
+    SlowDown,
+}
+
+impl From<proto::GetPageStatusCode> for GetPageStatusCode {
+    fn from(pb: proto::GetPageStatusCode) -> Self {
+        match pb {
+            proto::GetPageStatusCode::Unknown => Self::Unknown,
+            proto::GetPageStatusCode::Ok => Self::Ok,
+            proto::GetPageStatusCode::NotFound => Self::NotFound,
+            proto::GetPageStatusCode::InvalidRequest => Self::InvalidRequest,
+            proto::GetPageStatusCode::InternalError => Self::InternalError,
+            proto::GetPageStatusCode::SlowDown => Self::SlowDown,
+        }
+    }
+}
+
+impl From<i32> for GetPageStatusCode {
+    fn from(status_code: i32) -> Self {
+        proto::GetPageStatusCode::try_from(status_code)
+            .unwrap_or(proto::GetPageStatusCode::Unknown)
+            .into()
+    }
+}
+
+impl From<GetPageStatusCode> for proto::GetPageStatusCode {
+    fn from(status_code: GetPageStatusCode) -> Self {
+        match status_code {
+            GetPageStatusCode::Unknown => Self::Unknown,
+            GetPageStatusCode::Ok => Self::Ok,
+            GetPageStatusCode::NotFound => Self::NotFound,
+            GetPageStatusCode::InvalidRequest => Self::InvalidRequest,
+            GetPageStatusCode::InternalError => Self::InternalError,
+            GetPageStatusCode::SlowDown => Self::SlowDown,
+        }
+    }
+}
+
+impl From<GetPageStatusCode> for i32 {
+    fn from(status_code: GetPageStatusCode) -> Self {
+        proto::GetPageStatusCode::from(status_code).into()
+    }
+}
+
+// Fetches the size of a relation at a given LSN, as # of blocks. Only valid on shard 0, other
+// shards will error.
+pub struct GetRelSizeRequest {
+    pub read_lsn: ReadLsn,
+    pub rel: RelTag,
+}
+
+impl TryFrom<proto::GetRelSizeRequest> for GetRelSizeRequest {
+    type Error = ProtocolError;
+
+    fn try_from(proto: proto::GetRelSizeRequest) -> Result<Self, Self::Error> {
+        Ok(Self {
+            read_lsn: proto
+                .read_lsn
+                .ok_or(ProtocolError::Missing("read_lsn"))?
+                .try_into()?,
+            rel: proto.rel.ok_or(ProtocolError::Missing("rel"))?.try_into()?,
+        })
+    }
+}
+
+impl TryFrom<GetRelSizeRequest> for proto::GetRelSizeRequest {
+    type Error = ProtocolError;
+
+    fn try_from(request: GetRelSizeRequest) -> Result<Self, Self::Error> {
+        Ok(Self {
+            read_lsn: Some(request.read_lsn.try_into()?),
+            rel: Some(request.rel.into()),
+        })
+    }
+}
+
+pub type GetRelSizeResponse = u32;
+
+impl From<proto::GetRelSizeResponse> for GetRelSizeResponse {
+    fn from(proto: proto::GetRelSizeResponse) -> Self {
+        proto.num_blocks
+    }
+}
+
+impl From<GetRelSizeResponse> for proto::GetRelSizeResponse {
+    fn from(num_blocks: GetRelSizeResponse) -> Self {
+        Self { num_blocks }
+    }
+}
+
+/// Requests an SLRU segment. Only valid on shard 0, other shards will error.
+pub struct GetSlruSegmentRequest {
+    pub read_lsn: ReadLsn,
+    pub kind: SlruKind,
+    pub segno: u32,
+}
+
+impl TryFrom<proto::GetSlruSegmentRequest> for GetSlruSegmentRequest {
+    type Error = ProtocolError;
+
+    fn try_from(pb: proto::GetSlruSegmentRequest) -> Result<Self, Self::Error> {
+        Ok(Self {
+            read_lsn: pb
+                .read_lsn
+                .ok_or(ProtocolError::Missing("read_lsn"))?
+                .try_into()?,
+            kind: u8::try_from(pb.kind)
+                .ok()
+                .and_then(SlruKind::from_repr)
+                .ok_or_else(|| ProtocolError::invalid("slru_kind", pb.kind))?,
+            segno: pb.segno,
+        })
+    }
+}
+
+impl TryFrom<GetSlruSegmentRequest> for proto::GetSlruSegmentRequest {
+    type Error = ProtocolError;
+
+    fn try_from(request: GetSlruSegmentRequest) -> Result<Self, Self::Error> {
+        Ok(Self {
+            read_lsn: Some(request.read_lsn.try_into()?),
+            kind: request.kind as u32,
+            segno: request.segno,
+        })
+    }
+}
+
+pub type GetSlruSegmentResponse = Bytes;
+
+impl TryFrom<proto::GetSlruSegmentResponse> for GetSlruSegmentResponse {
+    type Error = ProtocolError;
+
+    fn try_from(pb: proto::GetSlruSegmentResponse) -> Result<Self, Self::Error> {
+        if pb.segment.is_empty() {
+            return Err(ProtocolError::Missing("segment"));
+        }
+        Ok(pb.segment)
+    }
+}
+
+impl TryFrom<GetSlruSegmentResponse> for proto::GetSlruSegmentResponse {
+    type Error = ProtocolError;
+
+    fn try_from(segment: GetSlruSegmentResponse) -> Result<Self, Self::Error> {
+        if segment.is_empty() {
+            return Err(ProtocolError::Missing("segment"));
+        }
+        Ok(Self { segment })
+    }
+}
+
+// SlruKind is defined in pageserver_api::reltag.
+pub type SlruKind = pageserver_api::reltag::SlruKind;
--- a/pageserver/src/basebackup.rs
+++ b/pageserver/src/basebackup.rs
@@ -144,7 +144,7 @@ where
        replica,
        ctx,
        io_concurrency: IoConcurrency::spawn_from_conf(
-            timeline.conf,
+            timeline.conf.get_vectored_concurrent_io,
            timeline
                .gate
                .enter()
@@ -343,7 +343,7 @@ where
            // Gather non-relational files from object storage pages.
            let slru_partitions = self
                .timeline
-                .get_slru_keyspace(Version::Lsn(self.lsn), self.ctx)
+                .get_slru_keyspace(Version::at(self.lsn), self.ctx)
                .await?
                .partition(
                    self.timeline.get_shard_identity(),
@@ -378,7 +378,7 @@ where
            // Otherwise only include init forks of unlogged relations.
            let rels = self
                .timeline
-                .list_rels(spcnode, dbnode, Version::Lsn(self.lsn), self.ctx)
+                .list_rels(spcnode, dbnode, Version::at(self.lsn), self.ctx)
                .await?;
            for &rel in rels.iter() {
                // Send init fork as main fork to provide well formed empty
@@ -517,7 +517,7 @@ where
    async fn add_rel(&mut self, src: RelTag, dst: RelTag) -> Result<(), BasebackupError> {
        let nblocks = self
            .timeline
-            .get_rel_size(src, Version::Lsn(self.lsn), self.ctx)
+            .get_rel_size(src, Version::at(self.lsn), self.ctx)
            .await?;

        // If the relation is empty, create an empty file
@@ -577,7 +577,7 @@ where
        let relmap_img = if has_relmap_file {
            let img = self
                .timeline
-                .get_relmap_file(spcnode, dbnode, Version::Lsn(self.lsn), self.ctx)
+                .get_relmap_file(spcnode, dbnode, Version::at(self.lsn), self.ctx)
                .await?;

            if img.len()
@@ -631,7 +631,7 @@ where
            if !has_relmap_file
                && self
                    .timeline
-                    .list_rels(spcnode, dbnode, Version::Lsn(self.lsn), self.ctx)
+                    .list_rels(spcnode, dbnode, Version::at(self.lsn), self.ctx)
                    .await?
                    .is_empty()
            {
--- a/pageserver/src/basebackup_cache.rs
+++ b/pageserver/src/basebackup_cache.rs
@@ -0,0 +1,518 @@
+use std::{collections::HashMap, sync::Arc};
+
+use async_compression::tokio::write::GzipEncoder;
+use camino::{Utf8Path, Utf8PathBuf};
+use metrics::core::{AtomicU64, GenericCounter};
+use pageserver_api::{config::BasebackupCacheConfig, models::TenantState};
+use tokio::{
+    io::{AsyncWriteExt, BufWriter},
+    sync::mpsc::{UnboundedReceiver, UnboundedSender},
+};
+use tokio_util::sync::CancellationToken;
+use utils::{
+    id::{TenantId, TenantTimelineId, TimelineId},
+    lsn::Lsn,
+    shard::TenantShardId,
+};
+
+use crate::{
+    basebackup::send_basebackup_tarball,
+    context::{DownloadBehavior, RequestContext},
+    metrics::{BASEBACKUP_CACHE_ENTRIES, BASEBACKUP_CACHE_PREPARE, BASEBACKUP_CACHE_READ},
+    task_mgr::TaskKind,
+    tenant::{
+        Timeline,
+        mgr::{TenantManager, TenantSlot},
+    },
+};
+
+pub struct BasebackupPrepareRequest {
+    pub tenant_shard_id: TenantShardId,
+    pub timeline_id: TimelineId,
+    pub lsn: Lsn,
+}
+
+pub type BasebackupPrepareSender = UnboundedSender<BasebackupPrepareRequest>;
+pub type BasebackupPrepareReceiver = UnboundedReceiver<BasebackupPrepareRequest>;
+
+type BasebackupRemoveEntrySender = UnboundedSender<Utf8PathBuf>;
+type BasebackupRemoveEntryReceiver = UnboundedReceiver<Utf8PathBuf>;
+
+/// BasebackupCache stores cached basebackup archives for timelines on local disk.
+///
+/// The main purpose of this cache is to speed up the startup process of compute nodes
+/// after scaling to zero.
+/// Thus, the basebackup is stored only for the latest LSN of the timeline and with
+/// fixed set of parameters (gzip=true, full_backup=false, replica=false, prev_lsn=none).
+///
+/// The cache receives prepare requests through the `BasebackupPrepareSender` channel,
+/// generates a basebackup from the timeline in the background, and stores it on disk.
+///
+/// Basebackup requests are pretty rare. We expect ~thousands of entries in the cache
+/// and ~1 RPS for get requests.
+pub struct BasebackupCache {
+    data_dir: Utf8PathBuf,
+    config: BasebackupCacheConfig,
+    tenant_manager: Arc<TenantManager>,
+    remove_entry_sender: BasebackupRemoveEntrySender,
+
+    entries: std::sync::Mutex<HashMap<TenantTimelineId, Lsn>>,
+
+    cancel: CancellationToken,
+
+    read_hit_count: GenericCounter<AtomicU64>,
+    read_miss_count: GenericCounter<AtomicU64>,
+    read_err_count: GenericCounter<AtomicU64>,
+
+    prepare_ok_count: GenericCounter<AtomicU64>,
+    prepare_skip_count: GenericCounter<AtomicU64>,
+    prepare_err_count: GenericCounter<AtomicU64>,
+}
+
+impl BasebackupCache {
+    /// Creates a BasebackupCache and spawns the background task.
+    /// The initialization of the cache is performed in the background and does not
+    /// block the caller. The cache will return `None` for any get requests until
+    /// initialization is complete.
+    pub fn spawn(
+        runtime_handle: &tokio::runtime::Handle,
+        data_dir: Utf8PathBuf,
+        config: Option<BasebackupCacheConfig>,
+        prepare_receiver: BasebackupPrepareReceiver,
+        tenant_manager: Arc<TenantManager>,
+        cancel: CancellationToken,
+    ) -> Arc<Self> {
+        let (remove_entry_sender, remove_entry_receiver) = tokio::sync::mpsc::unbounded_channel();
+
+        let enabled = config.is_some();
+
+        let cache = Arc::new(BasebackupCache {
+            data_dir,
+            config: config.unwrap_or_default(),
+            tenant_manager,
+            remove_entry_sender,
+
+            entries: std::sync::Mutex::new(HashMap::new()),
+
+            cancel,
+
+            read_hit_count: BASEBACKUP_CACHE_READ.with_label_values(&["hit"]),
+            read_miss_count: BASEBACKUP_CACHE_READ.with_label_values(&["miss"]),
+            read_err_count: BASEBACKUP_CACHE_READ.with_label_values(&["error"]),
+
+            prepare_ok_count: BASEBACKUP_CACHE_PREPARE.with_label_values(&["ok"]),
+            prepare_skip_count: BASEBACKUP_CACHE_PREPARE.with_label_values(&["skip"]),
+            prepare_err_count: BASEBACKUP_CACHE_PREPARE.with_label_values(&["error"]),
+        });
+
+        if enabled {
+            runtime_handle.spawn(
+                cache
+                    .clone()
+                    .background(prepare_receiver, remove_entry_receiver),
+            );
+        }
+
+        cache
+    }
+
+    /// Gets a basebackup entry from the cache.
+    /// If the entry is found, opens a file with the basebackup archive and returns it.
+    /// The open file descriptor will prevent the file system from deleting the file
+    /// even if the entry is removed from the cache in the background.
+    pub async fn get(
+        &self,
+        tenant_id: TenantId,
+        timeline_id: TimelineId,
+        lsn: Lsn,
+    ) -> Option<tokio::fs::File> {
+        // Fast path. Check if the entry exists using the in-memory state.
+        let tti = TenantTimelineId::new(tenant_id, timeline_id);
+        if self.entries.lock().unwrap().get(&tti) != Some(&lsn) {
+            self.read_miss_count.inc();
+            return None;
+        }
+
+        let path = self.entry_path(tenant_id, timeline_id, lsn);
+
+        match tokio::fs::File::open(path).await {
+            Ok(file) => {
+                self.read_hit_count.inc();
+                Some(file)
+            }
+            Err(e) => {
+                if e.kind() == std::io::ErrorKind::NotFound {
+                    // We may end up here if the basebackup was concurrently removed by the cleanup task.
+                    self.read_miss_count.inc();
+                } else {
+                    self.read_err_count.inc();
+                    tracing::warn!("Unexpected error opening basebackup cache file: {:?}", e);
+                }
+                None
+            }
+        }
+    }
+
+    // Private methods.
+
+    fn entry_filename(tenant_id: TenantId, timeline_id: TimelineId, lsn: Lsn) -> String {
+        // The default format for LSN is 0/ABCDEF.
+        // The backslash is not filename friendly, so serialize it as plain hex.
+        let lsn = lsn.0;
+        format!("basebackup_{tenant_id}_{timeline_id}_{lsn:016X}.tar.gz")
+    }
+
+    fn entry_path(&self, tenant_id: TenantId, timeline_id: TimelineId, lsn: Lsn) -> Utf8PathBuf {
+        self.data_dir
+            .join(Self::entry_filename(tenant_id, timeline_id, lsn))
+    }
+
+    fn entry_tmp_path(
+        &self,
+        tenant_id: TenantId,
+        timeline_id: TimelineId,
+        lsn: Lsn,
+    ) -> Utf8PathBuf {
+        self.data_dir
+            .join("tmp")
+            .join(Self::entry_filename(tenant_id, timeline_id, lsn))
+    }
+
+    fn parse_entry_filename(filename: &str) -> Option<(TenantId, TimelineId, Lsn)> {
+        let parts: Vec<&str> = filename
+            .strip_prefix("basebackup_")?
+            .strip_suffix(".tar.gz")?
+            .split('_')
+            .collect();
+        if parts.len() != 3 {
+            return None;
+        }
+        let tenant_id = parts[0].parse::<TenantId>().ok()?;
+        let timeline_id = parts[1].parse::<TimelineId>().ok()?;
+        let lsn = Lsn(u64::from_str_radix(parts[2], 16).ok()?);
+
+        Some((tenant_id, timeline_id, lsn))
+    }
+
+    async fn cleanup(&self) -> anyhow::Result<()> {
+        // Cleanup tmp directory.
+        let tmp_dir = self.data_dir.join("tmp");
+        let mut tmp_dir = tokio::fs::read_dir(&tmp_dir).await?;
+        while let Some(dir_entry) = tmp_dir.next_entry().await? {
+            if let Err(e) = tokio::fs::remove_file(dir_entry.path()).await {
+                tracing::warn!("Failed to remove basebackup cache tmp file: {:#}", e);
+            }
+        }
+
+        // Remove outdated entries.
+        let entries_old = self.entries.lock().unwrap().clone();
+        let mut entries_new = HashMap::new();
+        for (tenant_shard_id, tenant_slot) in self.tenant_manager.list() {
+            if !tenant_shard_id.is_shard_zero() {
+                continue;
+            }
+            let TenantSlot::Attached(tenant) = tenant_slot else {
+                continue;
+            };
+            let tenant_id = tenant_shard_id.tenant_id;
+
+            for timeline in tenant.list_timelines() {
+                let tti = TenantTimelineId::new(tenant_id, timeline.timeline_id);
+                if let Some(&entry_lsn) = entries_old.get(&tti) {
+                    if timeline.get_last_record_lsn() <= entry_lsn {
+                        entries_new.insert(tti, entry_lsn);
+                    }
+                }
+            }
+        }
+
+        for (&tti, &lsn) in entries_old.iter() {
+            if !entries_new.contains_key(&tti) {
+                self.remove_entry_sender
+                    .send(self.entry_path(tti.tenant_id, tti.timeline_id, lsn))
+                    .unwrap();
+            }
+        }
+
+        BASEBACKUP_CACHE_ENTRIES.set(entries_new.len() as i64);
+        *self.entries.lock().unwrap() = entries_new;
+
+        Ok(())
+    }
+
+    async fn on_startup(&self) -> anyhow::Result<()> {
+        // Create data_dir and tmp directory if they do not exist.
+        tokio::fs::create_dir_all(&self.data_dir.join("tmp"))
+            .await
+            .map_err(|e| {
+                anyhow::anyhow!(
+                    "Failed to create basebackup cache data_dir {:?}: {:?}",
+                    self.data_dir,
+                    e
+                )
+            })?;
+
+        // Read existing entries from the data_dir and add them to in-memory state.
+        let mut entries = HashMap::new();
+        let mut dir = tokio::fs::read_dir(&self.data_dir).await?;
+        while let Some(dir_entry) = dir.next_entry().await? {
+            let filename = dir_entry.file_name();
+
+            if filename == "tmp" {
+                // Skip the tmp directory.
+                continue;
+            }
+
+            let parsed = Self::parse_entry_filename(filename.to_string_lossy().as_ref());
+            let Some((tenant_id, timeline_id, lsn)) = parsed else {
+                tracing::warn!("Invalid basebackup cache file name: {:?}", filename);
+                continue;
+            };
+
+            let tti = TenantTimelineId::new(tenant_id, timeline_id);
+
+            use std::collections::hash_map::Entry::*;
+
+            match entries.entry(tti) {
+                Occupied(mut entry) => {
+                    let entry_lsn = *entry.get();
+                    // Leave only the latest entry, remove the old one.
+                    if lsn < entry_lsn {
+                        self.remove_entry_sender.send(self.entry_path(
+                            tenant_id,
+                            timeline_id,
+                            lsn,
+                        ))?;
+                    } else if lsn > entry_lsn {
+                        self.remove_entry_sender.send(self.entry_path(
+                            tenant_id,
+                            timeline_id,
+                            entry_lsn,
+                        ))?;
+                        entry.insert(lsn);
+                    } else {
+                        // Two different filenames parsed to the same timline_id and LSN.
+                        // Should never happen.
+                        return Err(anyhow::anyhow!(
+                            "Duplicate basebackup cache entry with the same LSN: {:?}",
+                            filename
+                        ));
+                    }
+                }
+                Vacant(entry) => {
+                    entry.insert(lsn);
+                }
+            }
+        }
+
+        BASEBACKUP_CACHE_ENTRIES.set(entries.len() as i64);
+        *self.entries.lock().unwrap() = entries;
+
+        Ok(())
+    }
+
+    async fn background(
+        self: Arc<Self>,
+        mut prepare_receiver: BasebackupPrepareReceiver,
+        mut remove_entry_receiver: BasebackupRemoveEntryReceiver,
+    ) {
+        // Panic in the background is a safe fallback.
+        // It will drop receivers and the cache will be effectively disabled.
+        self.on_startup()
+            .await
+            .expect("Failed to initialize basebackup cache");
+
+        let mut cleanup_ticker = tokio::time::interval(self.config.cleanup_period);
+        cleanup_ticker.set_missed_tick_behavior(tokio::time::MissedTickBehavior::Skip);
+
+        loop {
+            tokio::select! {
+                Some(req) = prepare_receiver.recv() => {
+                    if let Err(err) = self.prepare_basebackup(
+                        req.tenant_shard_id,
+                        req.timeline_id,
+                        req.lsn,
+                    ).await {
+                        tracing::info!("Failed to prepare basebackup: {:#}", err);
+                        self.prepare_err_count.inc();
+                        continue;
+                    }
+                }
+                Some(req) = remove_entry_receiver.recv() => {
+                    if let Err(e) = tokio::fs::remove_file(req).await {
+                        tracing::warn!("Failed to remove basebackup cache file: {:#}", e);
+                    }
+                }
+                _ = cleanup_ticker.tick() => {
+                    self.cleanup().await.unwrap_or_else(|e| {
+                        tracing::warn!("Failed to clean up basebackup cache: {:#}", e);
+                    });
+                }
+                _ = self.cancel.cancelled() => {
+                    tracing::info!("BasebackupCache background task cancelled");
+                    break;
+                }
+            }
+        }
+    }
+
+    /// Prepare a basebackup for the given timeline.
+    ///
+    /// If the basebackup already exists with a higher LSN or the timeline already
+    /// has a higher last_record_lsn, skip the preparation.
+    ///
+    /// The basebackup is prepared in a temporary directory and then moved to the final
+    /// location to make the operation atomic.
+    async fn prepare_basebackup(
+        &self,
+        tenant_shard_id: TenantShardId,
+        timeline_id: TimelineId,
+        req_lsn: Lsn,
+    ) -> anyhow::Result<()> {
+        tracing::info!(
+            tenant_id = %tenant_shard_id.tenant_id,
+            %timeline_id,
+            %req_lsn,
+            "Preparing basebackup for timeline",
+        );
+
+        let tti = TenantTimelineId::new(tenant_shard_id.tenant_id, timeline_id);
+
+        {
+            let entries = self.entries.lock().unwrap();
+            if let Some(&entry_lsn) = entries.get(&tti) {
+                if entry_lsn >= req_lsn {
+                    tracing::info!(
+                        %timeline_id,
+                        %req_lsn,
+                        %entry_lsn,
+                        "Basebackup entry already exists for timeline with higher LSN, skipping basebackup",
+                    );
+                    self.prepare_skip_count.inc();
+                    return Ok(());
+                }
+            }
+
+            if entries.len() as i64 >= self.config.max_size_entries {
+                tracing::info!(
+                    %timeline_id,
+                    %req_lsn,
+                    "Basebackup cache is full, skipping basebackup",
+                );
+                self.prepare_skip_count.inc();
+                return Ok(());
+            }
+        }
+
+        let tenant = self
+            .tenant_manager
+            .get_attached_tenant_shard(tenant_shard_id)?;
+
+        let tenant_state = tenant.current_state();
+        if tenant_state != TenantState::Active {
+            anyhow::bail!(
+                "Tenant {} is not active, current state: {:?}",
+                tenant_shard_id.tenant_id,
+                tenant_state
+            )
+        }
+
+        let timeline = tenant.get_timeline(timeline_id, true)?;
+
+        let last_record_lsn = timeline.get_last_record_lsn();
+        if last_record_lsn > req_lsn {
+            tracing::info!(
+                %timeline_id,
+                %req_lsn,
+                %last_record_lsn,
+                "Timeline has a higher LSN than the requested one, skipping basebackup",
+            );
+            self.prepare_skip_count.inc();
+            return Ok(());
+        }
+
+        let entry_tmp_path = self.entry_tmp_path(tenant_shard_id.tenant_id, timeline_id, req_lsn);
+
+        let res = self
+            .prepare_basebackup_tmp(&entry_tmp_path, &timeline, req_lsn)
+            .await;
+
+        if let Err(err) = res {
+            tracing::info!("Failed to prepare basebackup tmp file: {:#}", err);
+            // Try to clean up tmp file. If we fail, the background clean up task will take care of it.
+            match tokio::fs::remove_file(&entry_tmp_path).await {
+                Ok(_) => {}
+                Err(e) if e.kind() == std::io::ErrorKind::NotFound => {}
+                Err(e) => {
+                    tracing::info!("Failed to remove basebackup tmp file: {:?}", e);
+                }
+            }
+            return Err(err);
+        }
+
+        // Move the tmp file to the final location atomically.
+        let entry_path = self.entry_path(tenant_shard_id.tenant_id, timeline_id, req_lsn);
+        tokio::fs::rename(&entry_tmp_path, &entry_path).await?;
+
+        let mut entries = self.entries.lock().unwrap();
+        if let Some(old_lsn) = entries.insert(tti, req_lsn) {
+            // Remove the old entry if it exists.
+            self.remove_entry_sender
+                .send(self.entry_path(tenant_shard_id.tenant_id, timeline_id, old_lsn))
+                .unwrap();
+        }
+        BASEBACKUP_CACHE_ENTRIES.set(entries.len() as i64);
+
+        self.prepare_ok_count.inc();
+        Ok(())
+    }
+
+    /// Prepares a basebackup in a temporary file.
+    async fn prepare_basebackup_tmp(
+        &self,
+        emptry_tmp_path: &Utf8Path,
+        timeline: &Arc<Timeline>,
+        req_lsn: Lsn,
+    ) -> anyhow::Result<()> {
+        let ctx = RequestContext::new(TaskKind::BasebackupCache, DownloadBehavior::Download);
+        let ctx = ctx.with_scope_timeline(timeline);
+
+        let file = tokio::fs::File::create(emptry_tmp_path).await?;
+        let mut writer = BufWriter::new(file);
+
+        let mut encoder = GzipEncoder::with_quality(
+            &mut writer,
+            // Level::Best because compression is not on the hot path of basebackup requests.
+            // The decompression is almost not affected by the compression level.
+            async_compression::Level::Best,
+        );
+
+        // We may receive a request before the WAL record is applied to the timeline.
+        // Wait for the requested LSN to be applied.
+        timeline
+            .wait_lsn(
+                req_lsn,
+                crate::tenant::timeline::WaitLsnWaiter::BaseBackupCache,
+                crate::tenant::timeline::WaitLsnTimeout::Default,
+                &ctx,
+            )
+            .await?;
+
+        send_basebackup_tarball(
+            &mut encoder,
+            timeline,
+            Some(req_lsn),
+            None,
+            false,
+            false,
+            &ctx,
+        )
+        .await?;
+
+        encoder.shutdown().await?;
+        writer.flush().await?;
+        writer.into_inner().sync_all().await?;
+
+        Ok(())
+    }
+}
--- a/pageserver/src/bin/pageserver.rs
+++ b/pageserver/src/bin/pageserver.rs
@@ -16,10 +16,12 @@ use http_utils::tls_certs::ReloadingCertificateResolver;
 use metrics::launch_timestamp::{LaunchTimestamp, set_launch_timestamp_metric};
 use metrics::set_build_info_metric;
 use nix::sys::socket::{setsockopt, sockopt};
+use pageserver::basebackup_cache::BasebackupCache;
 use pageserver::config::{PageServerConf, PageserverIdentity, ignored_fields};
 use pageserver::controller_upcall_client::StorageControllerUpcallClient;
 use pageserver::deletion_queue::DeletionQueue;
 use pageserver::disk_usage_eviction_task::{self, launch_disk_usage_global_eviction_task};
+use pageserver::feature_resolver::FeatureResolver;
 use pageserver::metrics::{STARTUP_DURATION, STARTUP_IS_LOADING};
 use pageserver::task_mgr::{
    BACKGROUND_RUNTIME, COMPUTE_REQUEST_RUNTIME, MGMT_REQUEST_RUNTIME, WALRECEIVER_RUNTIME,
@@ -387,23 +389,30 @@ fn start_pageserver(
    // We need to release the lock file only when the process exits.
    std::mem::forget(lock_file);

-    // Bind the HTTP and libpq ports early, so that if they are in use by some other
-    // process, we error out early.
-    let http_addr = &conf.listen_http_addr;
-    info!("Starting pageserver http handler on {http_addr}");
-    let http_listener = tcp_listener::bind(http_addr)?;
+    // Bind the HTTP, libpq, and gRPC ports early, to error out if they are
+    // already in use.
+    info!(
+        "Starting pageserver http handler on {} with auth {:#?}",
+        conf.listen_http_addr, conf.http_auth_type
+    );
+    let http_listener = tcp_listener::bind(&conf.listen_http_addr)?;

    let https_listener = match conf.listen_https_addr.as_ref() {
        Some(https_addr) => {
-            info!("Starting pageserver https handler on {https_addr}");
+            info!(
+                "Starting pageserver https handler on {https_addr} with auth {:#?}",
+                conf.http_auth_type
+            );
            Some(tcp_listener::bind(https_addr)?)
        }
        None => None,
    };

-    let pg_addr = &conf.listen_pg_addr;
-    info!("Starting pageserver pg protocol handler on {pg_addr}");
-    let pageserver_listener = tcp_listener::bind(pg_addr)?;
+    info!(
+        "Starting pageserver pg protocol handler on {} with auth {:#?}",
+        conf.listen_pg_addr, conf.pg_auth_type,
+    );
+    let pageserver_listener = tcp_listener::bind(&conf.listen_pg_addr)?;

    // Enable SO_KEEPALIVE on the socket, to detect dead connections faster.
    // These are configured via net.ipv4.tcp_keepalive_* sysctls.
@@ -412,6 +421,15 @@ fn start_pageserver(
    // support enabling keepalives while using the default OS sysctls.
    setsockopt(&pageserver_listener, sockopt::KeepAlive, &true)?;

+    let mut grpc_listener = None;
+    if let Some(grpc_addr) = &conf.listen_grpc_addr {
+        info!(
+            "Starting pageserver gRPC handler on {grpc_addr} with auth {:#?}",
+            conf.grpc_auth_type
+        );
+        grpc_listener = Some(tcp_listener::bind(grpc_addr).map_err(|e| anyhow!("{e}"))?);
+    }
+
    // Launch broker client
    // The storage_broker::connect call needs to happen inside a tokio runtime thread.
    let broker_client = WALRECEIVER_RUNTIME
@@ -439,7 +457,8 @@ fn start_pageserver(
    // Initialize authentication for incoming connections
    let http_auth;
    let pg_auth;
-    if conf.http_auth_type == AuthType::NeonJWT || conf.pg_auth_type == AuthType::NeonJWT {
+    let grpc_auth;
+    if [conf.http_auth_type, conf.pg_auth_type, conf.grpc_auth_type].contains(&AuthType::NeonJWT) {
        // unwrap is ok because check is performed when creating config, so path is set and exists
        let key_path = conf.auth_validation_public_key_path.as_ref().unwrap();
        info!("Loading public key(s) for verifying JWT tokens from {key_path:?}");
@@ -447,20 +466,23 @@ fn start_pageserver(
        let jwt_auth = JwtAuth::from_key_path(key_path)?;
        let auth: Arc<SwappableJwtAuth> = Arc::new(SwappableJwtAuth::new(jwt_auth));

-        http_auth = match &conf.http_auth_type {
+        http_auth = match conf.http_auth_type {
            AuthType::Trust => None,
            AuthType::NeonJWT => Some(auth.clone()),
        };
-        pg_auth = match &conf.pg_auth_type {
+        pg_auth = match conf.pg_auth_type {
+            AuthType::Trust => None,
+            AuthType::NeonJWT => Some(auth.clone()),
+        };
+        grpc_auth = match conf.grpc_auth_type {
            AuthType::Trust => None,
            AuthType::NeonJWT => Some(auth),
        };
    } else {
        http_auth = None;
        pg_auth = None;
+        grpc_auth = None;
    }
-    info!("Using auth for http API: {:#?}", conf.http_auth_type);
-    info!("Using auth for pg connections: {:#?}", conf.pg_auth_type);

    let tls_server_config = if conf.listen_https_addr.is_some() || conf.enable_tls_page_service_api
    {
@@ -501,6 +523,12 @@ fn start_pageserver(
    // Set up remote storage client
    let remote_storage = BACKGROUND_RUNTIME.block_on(create_remote_storage_client(conf))?;

+    let feature_resolver = create_feature_resolver(
+        conf,
+        shutdown_pageserver.clone(),
+        BACKGROUND_RUNTIME.handle(),
+    )?;
+
    // Set up deletion queue
    let (deletion_queue, deletion_workers) = DeletionQueue::new(
        remote_storage.clone(),
@@ -541,6 +569,8 @@ fn start_pageserver(
        pageserver::l0_flush::L0FlushGlobalState::new(conf.l0_flush.clone());

    // Scan the local 'tenants/' directory and start loading the tenants
+    let (basebackup_prepare_sender, basebackup_prepare_receiver) =
+        tokio::sync::mpsc::unbounded_channel();
    let deletion_queue_client = deletion_queue.new_client();
    let background_purges = mgr::BackgroundPurges::default();
    let tenant_manager = BACKGROUND_RUNTIME.block_on(mgr::init_tenant_mgr(
@@ -551,12 +581,23 @@ fn start_pageserver(
            remote_storage: remote_storage.clone(),
            deletion_queue_client,
            l0_flush_global_state,
+            basebackup_prepare_sender,
+            feature_resolver,
        },
        order,
        shutdown_pageserver.clone(),
    ))?;
    let tenant_manager = Arc::new(tenant_manager);

+    let basebackup_cache = BasebackupCache::spawn(
+        BACKGROUND_RUNTIME.handle(),
+        conf.basebackup_cache_dir(),
+        conf.basebackup_cache_config.clone(),
+        basebackup_prepare_receiver,
+        Arc::clone(&tenant_manager),
+        shutdown_pageserver.child_token(),
+    );
+
    BACKGROUND_RUNTIME.spawn({
        let shutdown_pageserver = shutdown_pageserver.clone();
        let drive_init = async move {
@@ -763,8 +804,27 @@ fn start_pageserver(
        } else {
            None
        },
+        basebackup_cache.clone(),
    );

+    // Spawn a Pageserver gRPC server task. It will spawn separate tasks for
+    // each stream/request.
+    //
+    // TODO: this uses a separate Tokio runtime for the page service. If we want
+    // other gRPC services, they will need their own port and runtime. Is this
+    // necessary?
+    let mut page_service_grpc = None;
+    if let Some(grpc_listener) = grpc_listener {
+        page_service_grpc = Some(page_service::spawn_grpc(
+            conf,
+            tenant_manager.clone(),
+            grpc_auth,
+            otel_guard.as_ref().map(|g| g.dispatch.clone()),
+            grpc_listener,
+            basebackup_cache,
+        )?);
+    }
+
    // All started up! Now just sit and wait for shutdown signal.
    BACKGROUND_RUNTIME.block_on(async move {
        let signal_token = CancellationToken::new();
@@ -783,6 +843,7 @@ fn start_pageserver(
            http_endpoint_listener,
            https_endpoint_listener,
            page_service,
+            page_service_grpc,
            consumption_metrics_tasks,
            disk_usage_eviction_task,
            &tenant_manager,
@@ -796,6 +857,14 @@ fn start_pageserver(
    })
 }

+fn create_feature_resolver(
+    conf: &'static PageServerConf,
+    shutdown_pageserver: CancellationToken,
+    handle: &tokio::runtime::Handle,
+) -> anyhow::Result<FeatureResolver> {
+    FeatureResolver::spawn(conf, shutdown_pageserver, handle)
+}
+
 async fn create_remote_storage_client(
    conf: &'static PageServerConf,
 ) -> anyhow::Result<GenericRemoteStorage> {
--- a/pageserver/src/config.rs
+++ b/pageserver/src/config.rs
@@ -14,7 +14,7 @@ use std::time::Duration;
 use anyhow::{Context, bail, ensure};
 use camino::{Utf8Path, Utf8PathBuf};
 use once_cell::sync::OnceCell;
-use pageserver_api::config::{DiskUsageEvictionTaskConfig, MaxVectoredReadBytes};
+use pageserver_api::config::{DiskUsageEvictionTaskConfig, MaxVectoredReadBytes, PostHogConfig};
 use pageserver_api::models::ImageCompressionAlgorithm;
 use pageserver_api::shard::TenantShardId;
 use pem::Pem;
@@ -58,11 +58,16 @@ pub struct PageServerConf {
    pub listen_http_addr: String,
    /// Example: 127.0.0.1:9899
    pub listen_https_addr: Option<String>,
+    /// If set, expose a gRPC API on this address.
+    /// Example: 127.0.0.1:51051
+    ///
+    /// EXPERIMENTAL: this protocol is unstable and under active development.
+    pub listen_grpc_addr: Option<String>,

-    /// Path to a file with certificate's private key for https API.
+    /// Path to a file with certificate's private key for https and gRPC API.
    /// Default: server.key
    pub ssl_key_file: Utf8PathBuf,
-    /// Path to a file with a X509 certificate for https API.
+    /// Path to a file with a X509 certificate for https and gRPC API.
    /// Default: server.crt
    pub ssl_cert_file: Utf8PathBuf,
    /// Period to reload certificate and private key from files.
@@ -100,6 +105,8 @@ pub struct PageServerConf {
    pub http_auth_type: AuthType,
    /// authentication method for libpq connections from compute
    pub pg_auth_type: AuthType,
+    /// authentication method for gRPC connections from compute
+    pub grpc_auth_type: AuthType,
    /// Path to a file or directory containing public key(s) for verifying JWT tokens.
    /// Used for both mgmt and compute auth, if enabled.
    pub auth_validation_public_key_path: Option<Utf8PathBuf>,
@@ -231,7 +238,12 @@ pub struct PageServerConf {
    /// This is insecure and should only be used in development environments.
    pub dev_mode: bool,

+    /// PostHog integration config.
+    pub posthog_config: Option<PostHogConfig>,
+
    pub timeline_import_config: pageserver_api::config::TimelineImportConfig,
+
+    pub basebackup_cache_config: Option<pageserver_api::config::BasebackupCacheConfig>,
 }

 /// Token for authentication to safekeepers
@@ -261,6 +273,10 @@ impl PageServerConf {
        self.workdir.join("metadata.json")
    }

+    pub fn basebackup_cache_dir(&self) -> Utf8PathBuf {
+        self.workdir.join("basebackup_cache")
+    }
+
    pub fn deletion_list_path(&self, sequence: u64) -> Utf8PathBuf {
        // Encode a version in the filename, so that if we ever switch away from JSON we can
        // increment this.
@@ -349,6 +365,7 @@ impl PageServerConf {
            listen_pg_addr,
            listen_http_addr,
            listen_https_addr,
+            listen_grpc_addr,
            ssl_key_file,
            ssl_cert_file,
            ssl_cert_reload_period,
@@ -363,6 +380,7 @@ impl PageServerConf {
            pg_distrib_dir,
            http_auth_type,
            pg_auth_type,
+            grpc_auth_type,
            auth_validation_public_key_path,
            remote_storage,
            broker_endpoint,
@@ -406,7 +424,9 @@ impl PageServerConf {
            tracing,
            enable_tls_page_service_api,
            dev_mode,
+            posthog_config,
            timeline_import_config,
+            basebackup_cache_config,
        } = config_toml;

        let mut conf = PageServerConf {
@@ -416,6 +436,7 @@ impl PageServerConf {
            listen_pg_addr,
            listen_http_addr,
            listen_https_addr,
+            listen_grpc_addr,
            ssl_key_file,
            ssl_cert_file,
            ssl_cert_reload_period,
@@ -428,6 +449,7 @@ impl PageServerConf {
            max_file_descriptors,
            http_auth_type,
            pg_auth_type,
+            grpc_auth_type,
            auth_validation_public_key_path,
            remote_storage_config: remote_storage,
            broker_endpoint,
@@ -461,6 +483,7 @@ impl PageServerConf {
            enable_tls_page_service_api,
            dev_mode,
            timeline_import_config,
+            basebackup_cache_config,

            // ------------------------------------------------------------
            // fields that require additional validation or custom handling
@@ -517,13 +540,16 @@ impl PageServerConf {
                }
                None => Vec::new(),
            },
+            posthog_config,
        };

        // ------------------------------------------------------------
        // custom validation code that covers more than one field in isolation
        // ------------------------------------------------------------

-        if conf.http_auth_type == AuthType::NeonJWT || conf.pg_auth_type == AuthType::NeonJWT {
+        if [conf.http_auth_type, conf.pg_auth_type, conf.grpc_auth_type]
+            .contains(&AuthType::NeonJWT)
+        {
            let auth_validation_public_key_path = conf
                .auth_validation_public_key_path
                .get_or_insert_with(|| workdir.join("auth_public_key.pem"));
@@ -544,6 +570,23 @@ impl PageServerConf {
                    ratio.numerator, ratio.denominator
                )
            );
+
+            let url = Url::parse(&tracing_config.export_config.endpoint)
+                .map_err(anyhow::Error::msg)
+                .with_context(|| {
+                    format!(
+                        "tracing endpoint URL is invalid : {}",
+                        tracing_config.export_config.endpoint
+                    )
+                })?;
+
+            ensure!(
+                url.scheme() == "http" || url.scheme() == "https",
+                format!(
+                    "tracing endpoint URL must start with http:// or https://: {}",
+                    tracing_config.export_config.endpoint
+                )
+            );
        }

        IndexEntry::validate_checkpoint_distance(conf.default_tenant_conf.checkpoint_distance)
@@ -660,4 +703,25 @@ mod tests {
        PageServerConf::parse_and_validate(NodeId(0), config_toml, &workdir)
            .expect("parse_and_validate");
    }
+
+    #[test]
+    fn test_config_tracing_endpoint_is_invalid() {
+        let input = r#"
+            control_plane_api = "http://localhost:6666"
+
+            [tracing]
+
+            sampling_ratio = { numerator = 1, denominator = 0 }
+
+            [tracing.export_config]
+            endpoint = "localhost:4317"
+            protocol = "http-binary"
+            timeout = "1ms"
+        "#;
+        let config_toml = toml_edit::de::from_str::<pageserver_api::config::ConfigToml>(input)
+            .expect("config has valid fields");
+        let workdir = Utf8PathBuf::from("/nonexistent");
+        PageServerConf::parse_and_validate(NodeId(0), config_toml, &workdir)
+            .expect_err("parse_and_validate should fail for endpoint without scheme");
+    }
 }
--- a/pageserver/src/consumption_metrics/metrics.rs
+++ b/pageserver/src/consumption_metrics/metrics.rs
@@ -18,12 +18,25 @@ use crate::tenant::timeline::logical_size::CurrentLogicalSize;
 // management.
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, serde::Serialize, serde::Deserialize)]
 pub(super) enum Name {
-    /// Timeline last_record_lsn, absolute
+    /// Timeline last_record_lsn, absolute.
    #[serde(rename = "written_size")]
    WrittenSize,
    /// Timeline last_record_lsn, incremental
    #[serde(rename = "written_data_bytes_delta")]
    WrittenSizeDelta,
+    /// Written bytes only on this timeline (not including ancestors):
+    /// written_size - ancestor_lsn
+    ///
+    /// On the root branch, this is equivalent to `written_size`.
+    #[serde(rename = "written_size_since_parent")]
+    WrittenSizeSinceParent,
+    /// PITR history size only on this timeline (not including ancestors):
+    /// last_record_lsn - max(pitr_cutoff, ancestor_lsn).
+    ///
+    /// On the root branch, this is its entire PITR history size. Not emitted if GC hasn't computed
+    /// the PITR cutoff yet. 0 if PITR is disabled.
+    #[serde(rename = "pitr_history_size_since_parent")]
+    PitrHistorySizeSinceParent,
    /// Timeline logical size
    #[serde(rename = "timeline_logical_size")]
    LogicalSize,
@@ -157,6 +170,32 @@ impl MetricsKey {
        .incremental_values()
    }

+    /// `written_size` - `ancestor_lsn`.
+    const fn written_size_since_parent(
+        tenant_id: TenantId,
+        timeline_id: TimelineId,
+    ) -> AbsoluteValueFactory {
+        MetricsKey {
+            tenant_id,
+            timeline_id: Some(timeline_id),
+            metric: Name::WrittenSizeSinceParent,
+        }
+        .absolute_values()
+    }
+
+    /// `written_size` - max(`pitr_cutoff`, `ancestor_lsn`).
+    const fn pitr_history_size_since_parent(
+        tenant_id: TenantId,
+        timeline_id: TimelineId,
+    ) -> AbsoluteValueFactory {
+        MetricsKey {
+            tenant_id,
+            timeline_id: Some(timeline_id),
+            metric: Name::PitrHistorySizeSinceParent,
+        }
+        .absolute_values()
+    }
+
    /// Exact [`Timeline::get_current_logical_size`].
    ///
    /// [`Timeline::get_current_logical_size`]: crate::tenant::Timeline::get_current_logical_size
@@ -334,7 +373,13 @@ impl TenantSnapshot {
 struct TimelineSnapshot {
    loaded_at: (Lsn, SystemTime),
    last_record_lsn: Lsn,
+    ancestor_lsn: Lsn,
    current_exact_logical_size: Option<u64>,
+    /// Whether PITR is enabled (pitr_interval > 0).
+    pitr_enabled: bool,
+    /// The PITR cutoff LSN. None if not yet initialized. If PITR is disabled, this is approximately
+    /// Some(last_record_lsn), but may lag behind it since it's computed periodically.
+    pitr_cutoff: Option<Lsn>,
 }

 impl TimelineSnapshot {
@@ -354,6 +399,9 @@ impl TimelineSnapshot {
        } else {
            let loaded_at = t.loaded_at;
            let last_record_lsn = t.get_last_record_lsn();
+            let ancestor_lsn = t.get_ancestor_lsn();
+            let pitr_enabled = !t.get_pitr_interval().is_zero();
+            let pitr_cutoff = t.gc_info.read().unwrap().cutoffs.time;

            let current_exact_logical_size = {
                let span = tracing::info_span!("collect_metrics_iteration", tenant_id = %t.tenant_shard_id.tenant_id, timeline_id = %t.timeline_id);
@@ -373,7 +421,10 @@ impl TimelineSnapshot {
            Ok(Some(TimelineSnapshot {
                loaded_at,
                last_record_lsn,
+                ancestor_lsn,
                current_exact_logical_size,
+                pitr_enabled,
+                pitr_cutoff,
            }))
        }
    }
@@ -424,6 +475,8 @@ impl TimelineSnapshot {

        let up_to = now;

+        let written_size_last = written_size_now.value.max(prev.1); // don't regress
+
        if let Some(delta) = written_size_now.value.checked_sub(prev.1) {
            let key_value = written_size_delta_key.from_until(prev.0, up_to, delta);
            // written_size_delta
@@ -441,6 +494,27 @@ impl TimelineSnapshot {
            });
        }

+        // Compute the branch-local written size.
+        let written_size_since_parent_key =
+            MetricsKey::written_size_since_parent(tenant_id, timeline_id);
+        metrics.push(
+            written_size_since_parent_key
+                .at(now, written_size_last.saturating_sub(self.ancestor_lsn.0)),
+        );
+
+        // Compute the branch-local PITR history size. Not emitted if GC hasn't yet computed the
+        // PITR cutoff. 0 if PITR is disabled.
+        let pitr_history_size_since_parent_key =
+            MetricsKey::pitr_history_size_since_parent(tenant_id, timeline_id);
+        if !self.pitr_enabled {
+            metrics.push(pitr_history_size_since_parent_key.at(now, 0));
+        } else if let Some(pitr_cutoff) = self.pitr_cutoff {
+            metrics.push(pitr_history_size_since_parent_key.at(
+                now,
+                written_size_last.saturating_sub(pitr_cutoff.max(self.ancestor_lsn).0),
+            ));
+        }
+
        {
            let factory = MetricsKey::timeline_logical_size(tenant_id, timeline_id);
            let current_or_previous = self
--- a/pageserver/src/consumption_metrics/metrics/tests.rs
+++ b/pageserver/src/consumption_metrics/metrics/tests.rs
@@ -12,12 +12,17 @@ fn startup_collected_timeline_metrics_before_advancing() {
    let cache = HashMap::new();

    let initdb_lsn = Lsn(0x10000);
+    let pitr_cutoff = Lsn(0x11000);
    let disk_consistent_lsn = Lsn(initdb_lsn.0 * 2);
+    let logical_size = 0x42000;

    let snap = TimelineSnapshot {
        loaded_at: (disk_consistent_lsn, SystemTime::now()),
        last_record_lsn: disk_consistent_lsn,
-        current_exact_logical_size: Some(0x42000),
+        ancestor_lsn: Lsn(0),
+        current_exact_logical_size: Some(logical_size),
+        pitr_enabled: true,
+        pitr_cutoff: Some(pitr_cutoff),
    };

    let now = DateTime::<Utc>::from(SystemTime::now());
@@ -33,7 +38,11 @@ fn startup_collected_timeline_metrics_before_advancing() {
                0
            ),
            MetricsKey::written_size(tenant_id, timeline_id).at(now, disk_consistent_lsn.0),
-            MetricsKey::timeline_logical_size(tenant_id, timeline_id).at(now, 0x42000)
+            MetricsKey::written_size_since_parent(tenant_id, timeline_id)
+                .at(now, disk_consistent_lsn.0),
+            MetricsKey::pitr_history_size_since_parent(tenant_id, timeline_id)
+                .at(now, disk_consistent_lsn.0 - pitr_cutoff.0),
+            MetricsKey::timeline_logical_size(tenant_id, timeline_id).at(now, logical_size)
        ]
    );
 }
@@ -49,7 +58,9 @@ fn startup_collected_timeline_metrics_second_round() {
    let before = DateTime::<Utc>::from(before);

    let initdb_lsn = Lsn(0x10000);
+    let pitr_cutoff = Lsn(0x11000);
    let disk_consistent_lsn = Lsn(initdb_lsn.0 * 2);
+    let logical_size = 0x42000;

    let mut metrics = Vec::new();
    let cache = HashMap::from([MetricsKey::written_size(tenant_id, timeline_id)
@@ -59,7 +70,10 @@ fn startup_collected_timeline_metrics_second_round() {
    let snap = TimelineSnapshot {
        loaded_at: (disk_consistent_lsn, init),
        last_record_lsn: disk_consistent_lsn,
-        current_exact_logical_size: Some(0x42000),
+        ancestor_lsn: Lsn(0),
+        current_exact_logical_size: Some(logical_size),
+        pitr_enabled: true,
+        pitr_cutoff: Some(pitr_cutoff),
    };

    snap.to_metrics(tenant_id, timeline_id, now, &mut metrics, &cache);
@@ -69,7 +83,11 @@ fn startup_collected_timeline_metrics_second_round() {
        &[
            MetricsKey::written_size_delta(tenant_id, timeline_id).from_until(before, now, 0),
            MetricsKey::written_size(tenant_id, timeline_id).at(now, disk_consistent_lsn.0),
-            MetricsKey::timeline_logical_size(tenant_id, timeline_id).at(now, 0x42000)
+            MetricsKey::written_size_since_parent(tenant_id, timeline_id)
+                .at(now, disk_consistent_lsn.0),
+            MetricsKey::pitr_history_size_since_parent(tenant_id, timeline_id)
+                .at(now, disk_consistent_lsn.0 - pitr_cutoff.0),
+            MetricsKey::timeline_logical_size(tenant_id, timeline_id).at(now, logical_size)
        ]
    );
 }
@@ -86,7 +104,9 @@ fn startup_collected_timeline_metrics_nth_round_at_same_lsn() {
    let before = DateTime::<Utc>::from(before);

    let initdb_lsn = Lsn(0x10000);
+    let pitr_cutoff = Lsn(0x11000);
    let disk_consistent_lsn = Lsn(initdb_lsn.0 * 2);
+    let logical_size = 0x42000;

    let mut metrics = Vec::new();
    let cache = HashMap::from([
@@ -103,7 +123,10 @@ fn startup_collected_timeline_metrics_nth_round_at_same_lsn() {
    let snap = TimelineSnapshot {
        loaded_at: (disk_consistent_lsn, init),
        last_record_lsn: disk_consistent_lsn,
-        current_exact_logical_size: Some(0x42000),
+        ancestor_lsn: Lsn(0),
+        current_exact_logical_size: Some(logical_size),
+        pitr_enabled: true,
+        pitr_cutoff: Some(pitr_cutoff),
    };

    snap.to_metrics(tenant_id, timeline_id, now, &mut metrics, &cache);
@@ -113,16 +136,18 @@ fn startup_collected_timeline_metrics_nth_round_at_same_lsn() {
        &[
            MetricsKey::written_size_delta(tenant_id, timeline_id).from_until(just_before, now, 0),
            MetricsKey::written_size(tenant_id, timeline_id).at(now, disk_consistent_lsn.0),
-            MetricsKey::timeline_logical_size(tenant_id, timeline_id).at(now, 0x42000)
+            MetricsKey::written_size_since_parent(tenant_id, timeline_id)
+                .at(now, disk_consistent_lsn.0),
+            MetricsKey::pitr_history_size_since_parent(tenant_id, timeline_id)
+                .at(now, disk_consistent_lsn.0 - pitr_cutoff.0),
+            MetricsKey::timeline_logical_size(tenant_id, timeline_id).at(now, logical_size)
        ]
    );
 }

+/// Tests that written sizes do not regress across restarts.
 #[test]
 fn post_restart_written_sizes_with_rolled_back_last_record_lsn() {
-    // it can happen that we lose the inmemorylayer but have previously sent metrics and we
-    // should never go backwards
-
    let tenant_id = TenantId::generate();
    let timeline_id = TimelineId::generate();

@@ -140,7 +165,10 @@ fn post_restart_written_sizes_with_rolled_back_last_record_lsn() {
    let snap = TimelineSnapshot {
        loaded_at: (Lsn(50), at_restart),
        last_record_lsn: Lsn(50),
+        ancestor_lsn: Lsn(0),
        current_exact_logical_size: None,
+        pitr_enabled: true,
+        pitr_cutoff: Some(Lsn(20)),
    };

    let mut cache = HashMap::from([
@@ -169,6 +197,8 @@ fn post_restart_written_sizes_with_rolled_back_last_record_lsn() {
                0
            ),
            MetricsKey::written_size(tenant_id, timeline_id).at(now, 100),
+            MetricsKey::written_size_since_parent(tenant_id, timeline_id).at(now, 100),
+            MetricsKey::pitr_history_size_since_parent(tenant_id, timeline_id).at(now, 80),
        ]
    );

@@ -183,6 +213,157 @@ fn post_restart_written_sizes_with_rolled_back_last_record_lsn() {
        &[
            MetricsKey::written_size_delta(tenant_id, timeline_id).from_until(now, later, 0),
            MetricsKey::written_size(tenant_id, timeline_id).at(later, 100),
+            MetricsKey::written_size_since_parent(tenant_id, timeline_id).at(later, 100),
+            MetricsKey::pitr_history_size_since_parent(tenant_id, timeline_id).at(later, 80),
+        ]
+    );
+}
+
+/// Tests that written sizes do not regress across restarts, even on child branches.
+#[test]
+fn post_restart_written_sizes_with_rolled_back_last_record_lsn_and_ancestor_lsn() {
+    let tenant_id = TenantId::generate();
+    let timeline_id = TimelineId::generate();
+
+    let [later, now, at_restart] = time_backwards();
+
+    // FIXME: tests would be so much easier if we did not need to juggle back and forth
+    // SystemTime and DateTime::<Utc> ... Could do the conversion only at upload time?
+    let now = DateTime::<Utc>::from(now);
+    let later = DateTime::<Utc>::from(later);
+    let before_restart = at_restart - std::time::Duration::from_secs(5 * 60);
+    let way_before = before_restart - std::time::Duration::from_secs(10 * 60);
+    let before_restart = DateTime::<Utc>::from(before_restart);
+    let way_before = DateTime::<Utc>::from(way_before);
+
+    let snap = TimelineSnapshot {
+        loaded_at: (Lsn(50), at_restart),
+        last_record_lsn: Lsn(50),
+        ancestor_lsn: Lsn(40),
+        current_exact_logical_size: None,
+        pitr_enabled: true,
+        pitr_cutoff: Some(Lsn(20)),
+    };
+
+    let mut cache = HashMap::from([
+        MetricsKey::written_size(tenant_id, timeline_id)
+            .at(before_restart, 100)
+            .to_kv_pair(),
+        MetricsKey::written_size_delta(tenant_id, timeline_id)
+            .from_until(
+                way_before,
+                before_restart,
+                // not taken into account, but the timestamps are important
+                999_999_999,
+            )
+            .to_kv_pair(),
+    ]);
+
+    let mut metrics = Vec::new();
+    snap.to_metrics(tenant_id, timeline_id, now, &mut metrics, &cache);
+
+    assert_eq!(
+        metrics,
+        &[
+            MetricsKey::written_size_delta(tenant_id, timeline_id).from_until(
+                before_restart,
+                now,
+                0
+            ),
+            MetricsKey::written_size(tenant_id, timeline_id).at(now, 100),
+            MetricsKey::written_size_since_parent(tenant_id, timeline_id).at(now, 60),
+            MetricsKey::pitr_history_size_since_parent(tenant_id, timeline_id).at(now, 60),
+        ]
+    );
+
+    // now if we cache these metrics, and re-run while "still in recovery"
+    cache.extend(metrics.drain(..).map(|x| x.to_kv_pair()));
+
+    // "still in recovery", because our snapshot did not change
+    snap.to_metrics(tenant_id, timeline_id, later, &mut metrics, &cache);
+
+    assert_eq!(
+        metrics,
+        &[
+            MetricsKey::written_size_delta(tenant_id, timeline_id).from_until(now, later, 0),
+            MetricsKey::written_size(tenant_id, timeline_id).at(later, 100),
+            MetricsKey::written_size_since_parent(tenant_id, timeline_id).at(later, 60),
+            MetricsKey::pitr_history_size_since_parent(tenant_id, timeline_id).at(later, 60),
+        ]
+    );
+}
+
+/// Tests that written sizes do not regress across restarts, even on child branches and
+/// with a PITR cutoff after the branch point.
+#[test]
+fn post_restart_written_sizes_with_rolled_back_last_record_lsn_and_ancestor_lsn_and_pitr_cutoff() {
+    let tenant_id = TenantId::generate();
+    let timeline_id = TimelineId::generate();
+
+    let [later, now, at_restart] = time_backwards();
+
+    // FIXME: tests would be so much easier if we did not need to juggle back and forth
+    // SystemTime and DateTime::<Utc> ... Could do the conversion only at upload time?
+    let now = DateTime::<Utc>::from(now);
+    let later = DateTime::<Utc>::from(later);
+    let before_restart = at_restart - std::time::Duration::from_secs(5 * 60);
+    let way_before = before_restart - std::time::Duration::from_secs(10 * 60);
+    let before_restart = DateTime::<Utc>::from(before_restart);
+    let way_before = DateTime::<Utc>::from(way_before);
+
+    let snap = TimelineSnapshot {
+        loaded_at: (Lsn(50), at_restart),
+        last_record_lsn: Lsn(50),
+        ancestor_lsn: Lsn(30),
+        current_exact_logical_size: None,
+        pitr_enabled: true,
+        pitr_cutoff: Some(Lsn(40)),
+    };
+
+    let mut cache = HashMap::from([
+        MetricsKey::written_size(tenant_id, timeline_id)
+            .at(before_restart, 100)
+            .to_kv_pair(),
+        MetricsKey::written_size_delta(tenant_id, timeline_id)
+            .from_until(
+                way_before,
+                before_restart,
+                // not taken into account, but the timestamps are important
+                999_999_999,
+            )
+            .to_kv_pair(),
+    ]);
+
+    let mut metrics = Vec::new();
+    snap.to_metrics(tenant_id, timeline_id, now, &mut metrics, &cache);
+
+    assert_eq!(
+        metrics,
+        &[
+            MetricsKey::written_size_delta(tenant_id, timeline_id).from_until(
+                before_restart,
+                now,
+                0
+            ),
+            MetricsKey::written_size(tenant_id, timeline_id).at(now, 100),
+            MetricsKey::written_size_since_parent(tenant_id, timeline_id).at(now, 70),
+            MetricsKey::pitr_history_size_since_parent(tenant_id, timeline_id).at(now, 60),
+        ]
+    );
+
+    // now if we cache these metrics, and re-run while "still in recovery"
+    cache.extend(metrics.drain(..).map(|x| x.to_kv_pair()));
+
+    // "still in recovery", because our snapshot did not change
+    snap.to_metrics(tenant_id, timeline_id, later, &mut metrics, &cache);
+
+    assert_eq!(
+        metrics,
+        &[
+            MetricsKey::written_size_delta(tenant_id, timeline_id).from_until(now, later, 0),
+            MetricsKey::written_size(tenant_id, timeline_id).at(later, 100),
+            MetricsKey::written_size_since_parent(tenant_id, timeline_id).at(later, 70),
+            MetricsKey::pitr_history_size_since_parent(tenant_id, timeline_id).at(later, 60),
        ]
    );
 }
@@ -201,7 +382,10 @@ fn post_restart_current_exact_logical_size_uses_cached() {
    let snap = TimelineSnapshot {
        loaded_at: (Lsn(50), at_restart),
        last_record_lsn: Lsn(50),
+        ancestor_lsn: Lsn(0),
        current_exact_logical_size: None,
+        pitr_enabled: true,
+        pitr_cutoff: None,
    };

    let cache = HashMap::from([MetricsKey::timeline_logical_size(tenant_id, timeline_id)
@@ -286,16 +470,101 @@ fn time_backwards<const N: usize>() -> [std::time::SystemTime; N] {
    times
 }

+/// Tests that disabled PITR history does not yield any history size, even when the PITR cutoff
+/// indicates otherwise.
+#[test]
+fn pitr_disabled_yields_no_history_size() {
+    let tenant_id = TenantId::generate();
+    let timeline_id = TimelineId::generate();
+
+    let mut metrics = Vec::new();
+    let cache = HashMap::new();
+
+    let initdb_lsn = Lsn(0x10000);
+    let pitr_cutoff = Lsn(0x11000);
+    let disk_consistent_lsn = Lsn(initdb_lsn.0 * 2);
+
+    let snap = TimelineSnapshot {
+        loaded_at: (disk_consistent_lsn, SystemTime::now()),
+        last_record_lsn: disk_consistent_lsn,
+        ancestor_lsn: Lsn(0),
+        current_exact_logical_size: None,
+        pitr_enabled: false,
+        pitr_cutoff: Some(pitr_cutoff),
+    };
+
+    let now = DateTime::<Utc>::from(SystemTime::now());
+
+    snap.to_metrics(tenant_id, timeline_id, now, &mut metrics, &cache);
+
+    assert_eq!(
+        metrics,
+        &[
+            MetricsKey::written_size_delta(tenant_id, timeline_id).from_until(
+                snap.loaded_at.1.into(),
+                now,
+                0
+            ),
+            MetricsKey::written_size(tenant_id, timeline_id).at(now, disk_consistent_lsn.0),
+            MetricsKey::written_size_since_parent(tenant_id, timeline_id)
+                .at(now, disk_consistent_lsn.0),
+            MetricsKey::pitr_history_size_since_parent(tenant_id, timeline_id).at(now, 0),
+        ]
+    );
+}
+
+/// Tests that uninitialized PITR cutoff does not emit any history size metric at all.
+#[test]
+fn pitr_uninitialized_does_not_emit_history_size() {
+    let tenant_id = TenantId::generate();
+    let timeline_id = TimelineId::generate();
+
+    let mut metrics = Vec::new();
+    let cache = HashMap::new();
+
+    let initdb_lsn = Lsn(0x10000);
+    let disk_consistent_lsn = Lsn(initdb_lsn.0 * 2);
+
+    let snap = TimelineSnapshot {
+        loaded_at: (disk_consistent_lsn, SystemTime::now()),
+        last_record_lsn: disk_consistent_lsn,
+        ancestor_lsn: Lsn(0),
+        current_exact_logical_size: None,
+        pitr_enabled: true,
+        pitr_cutoff: None,
+    };
+
+    let now = DateTime::<Utc>::from(SystemTime::now());
+
+    snap.to_metrics(tenant_id, timeline_id, now, &mut metrics, &cache);
+
+    assert_eq!(
+        metrics,
+        &[
+            MetricsKey::written_size_delta(tenant_id, timeline_id).from_until(
+                snap.loaded_at.1.into(),
+                now,
+                0
+            ),
+            MetricsKey::written_size(tenant_id, timeline_id).at(now, disk_consistent_lsn.0),
+            MetricsKey::written_size_since_parent(tenant_id, timeline_id)
+                .at(now, disk_consistent_lsn.0),
+        ]
+    );
+}
+
 pub(crate) const fn metric_examples_old(
    tenant_id: TenantId,
    timeline_id: TimelineId,
    now: DateTime<Utc>,
    before: DateTime<Utc>,
-) -> [RawMetric; 5] {
+) -> [RawMetric; 7] {
    [
        MetricsKey::written_size(tenant_id, timeline_id).at_old_format(now, 0),
        MetricsKey::written_size_delta(tenant_id, timeline_id)
            .from_until_old_format(before, now, 0),
+        MetricsKey::written_size_since_parent(tenant_id, timeline_id).at_old_format(now, 0),
+        MetricsKey::pitr_history_size_since_parent(tenant_id, timeline_id).at_old_format(now, 0),
        MetricsKey::timeline_logical_size(tenant_id, timeline_id).at_old_format(now, 0),
        MetricsKey::remote_storage_size(tenant_id).at_old_format(now, 0),
        MetricsKey::synthetic_size(tenant_id).at_old_format(now, 1),
@@ -307,10 +576,12 @@ pub(crate) const fn metric_examples(
    timeline_id: TimelineId,
    now: DateTime<Utc>,
    before: DateTime<Utc>,
-) -> [NewRawMetric; 5] {
+) -> [NewRawMetric; 7] {
    [
        MetricsKey::written_size(tenant_id, timeline_id).at(now, 0),
        MetricsKey::written_size_delta(tenant_id, timeline_id).from_until(before, now, 0),
+        MetricsKey::written_size_since_parent(tenant_id, timeline_id).at(now, 0),
+        MetricsKey::pitr_history_size_since_parent(tenant_id, timeline_id).at(now, 0),
        MetricsKey::timeline_logical_size(tenant_id, timeline_id).at(now, 0),
        MetricsKey::remote_storage_size(tenant_id).at(now, 0),
        MetricsKey::synthetic_size(tenant_id).at(now, 1),
--- a/pageserver/src/consumption_metrics/upload.rs
+++ b/pageserver/src/consumption_metrics/upload.rs
@@ -513,6 +513,14 @@ mod tests {
                line!(),
                r#"{"type":"incremental","start_time":"2023-09-14T00:00:00.123456789Z","stop_time":"2023-09-15T00:00:00.123456789Z","metric":"written_data_bytes_delta","idempotency_key":"2023-09-15 00:00:00.123456789 UTC-1-0000","value":0,"tenant_id":"00000000000000000000000000000000","timeline_id":"ffffffffffffffffffffffffffffffff"}"#,
            ),
+            (
+                line!(),
+                r#"{"type":"absolute","time":"2023-09-15T00:00:00.123456789Z","metric":"written_size_since_parent","idempotency_key":"2023-09-15 00:00:00.123456789 UTC-1-0000","value":0,"tenant_id":"00000000000000000000000000000000","timeline_id":"ffffffffffffffffffffffffffffffff"}"#,
+            ),
+            (
+                line!(),
+                r#"{"type":"absolute","time":"2023-09-15T00:00:00.123456789Z","metric":"pitr_history_size_since_parent","idempotency_key":"2023-09-15 00:00:00.123456789 UTC-1-0000","value":0,"tenant_id":"00000000000000000000000000000000","timeline_id":"ffffffffffffffffffffffffffffffff"}"#,
+            ),
            (
                line!(),
                r#"{"type":"absolute","time":"2023-09-15T00:00:00.123456789Z","metric":"timeline_logical_size","idempotency_key":"2023-09-15 00:00:00.123456789 UTC-1-0000","value":0,"tenant_id":"00000000000000000000000000000000","timeline_id":"ffffffffffffffffffffffffffffffff"}"#,
@@ -560,7 +568,7 @@ mod tests {
        assert_eq!(upgraded_samples, new_samples);
    }

-    fn metric_samples_old() -> [RawMetric; 5] {
+    fn metric_samples_old() -> [RawMetric; 7] {
        let tenant_id = TenantId::from_array([0; 16]);
        let timeline_id = TimelineId::from_array([0xff; 16]);

@@ -572,7 +580,7 @@ mod tests {
        super::super::metrics::metric_examples_old(tenant_id, timeline_id, now, before)
    }

-    fn metric_samples() -> [NewRawMetric; 5] {
+    fn metric_samples() -> [NewRawMetric; 7] {
        let tenant_id = TenantId::from_array([0; 16]);
        let timeline_id = TimelineId::from_array([0xff; 16]);

--- a/pageserver/src/disk_usage_eviction_task.rs
+++ b/pageserver/src/disk_usage_eviction_task.rs
@@ -837,7 +837,30 @@ async fn collect_eviction_candidates(
                continue;
            }
            let info = tl.get_local_layers_for_disk_usage_eviction().await;
-            debug!(tenant_id=%tl.tenant_shard_id.tenant_id, shard_id=%tl.tenant_shard_id.shard_slug(), timeline_id=%tl.timeline_id, "timeline resident layers count: {}", info.resident_layers.len());
+            debug!(
+                tenant_id=%tl.tenant_shard_id.tenant_id,
+                shard_id=%tl.tenant_shard_id.shard_slug(),
+                timeline_id=%tl.timeline_id,
+                "timeline resident layers count: {}", info.resident_layers.len()
+            );
+
+            tenant_candidates.extend(info.resident_layers.into_iter());
+            max_layer_size = max_layer_size.max(info.max_layer_size.unwrap_or(0));
+
+            if cancel.is_cancelled() {
+                return Ok(EvictionCandidates::Cancelled);
+            }
+        }
+
+        // Also consider layers of timelines being imported for eviction
+        for tl in tenant.list_importing_timelines() {
+            let info = tl.timeline.get_local_layers_for_disk_usage_eviction().await;
+            debug!(
+                tenant_id=%tl.timeline.tenant_shard_id.tenant_id,
+                shard_id=%tl.timeline.tenant_shard_id.shard_slug(),
+                timeline_id=%tl.timeline.timeline_id,
+                "timeline resident layers count: {}", info.resident_layers.len()
+            );

            tenant_candidates.extend(info.resident_layers.into_iter());
            max_layer_size = max_layer_size.max(info.max_layer_size.unwrap_or(0));
--- a/pageserver/src/feature_resolver.rs
+++ b/pageserver/src/feature_resolver.rs
@@ -0,0 +1,104 @@
+use std::{collections::HashMap, sync::Arc, time::Duration};
+
+use posthog_client_lite::{
+    FeatureResolverBackgroundLoop, PostHogClientConfig, PostHogEvaluationError,
+};
+use tokio_util::sync::CancellationToken;
+use utils::id::TenantId;
+
+use crate::config::PageServerConf;
+
+#[derive(Clone)]
+pub struct FeatureResolver {
+    inner: Option<Arc<FeatureResolverBackgroundLoop>>,
+}
+
+impl FeatureResolver {
+    pub fn new_disabled() -> Self {
+        Self { inner: None }
+    }
+
+    pub fn spawn(
+        conf: &PageServerConf,
+        shutdown_pageserver: CancellationToken,
+        handle: &tokio::runtime::Handle,
+    ) -> anyhow::Result<Self> {
+        // DO NOT block in this function: make it return as fast as possible to avoid startup delays.
+        if let Some(posthog_config) = &conf.posthog_config {
+            let inner = FeatureResolverBackgroundLoop::new(
+                PostHogClientConfig {
+                    server_api_key: posthog_config.server_api_key.clone(),
+                    client_api_key: posthog_config.client_api_key.clone(),
+                    project_id: posthog_config.project_id.clone(),
+                    private_api_url: posthog_config.private_api_url.clone(),
+                    public_api_url: posthog_config.public_api_url.clone(),
+                },
+                shutdown_pageserver,
+            );
+            let inner = Arc::new(inner);
+            // TODO: make this configurable
+            inner.clone().spawn(handle, Duration::from_secs(60));
+            Ok(FeatureResolver { inner: Some(inner) })
+        } else {
+            Ok(FeatureResolver { inner: None })
+        }
+    }
+
+    /// Evaluate a multivariate feature flag. Currently, we do not support any properties.
+    ///
+    /// Error handling: the caller should inspect the error and decide the behavior when a feature flag
+    /// cannot be evaluated (i.e., default to false if it cannot be resolved). The error should *not* be
+    /// propagated beyond where the feature flag gets resolved.
+    pub fn evaluate_multivariate(
+        &self,
+        flag_key: &str,
+        tenant_id: TenantId,
+    ) -> Result<String, PostHogEvaluationError> {
+        if let Some(inner) = &self.inner {
+            inner.feature_store().evaluate_multivariate(
+                flag_key,
+                &tenant_id.to_string(),
+                &HashMap::new(),
+            )
+        } else {
+            Err(PostHogEvaluationError::NotAvailable(
+                "PostHog integration is not enabled".to_string(),
+            ))
+        }
+    }
+
+    /// Evaluate a boolean feature flag. Currently, we do not support any properties.
+    ///
+    /// Returns `Ok(())` if the flag is evaluated to true, otherwise returns an error.
+    ///
+    /// Error handling: the caller should inspect the error and decide the behavior when a feature flag
+    /// cannot be evaluated (i.e., default to false if it cannot be resolved). The error should *not* be
+    /// propagated beyond where the feature flag gets resolved.
+    pub fn evaluate_boolean(
+        &self,
+        flag_key: &str,
+        tenant_id: TenantId,
+    ) -> Result<(), PostHogEvaluationError> {
+        if let Some(inner) = &self.inner {
+            inner.feature_store().evaluate_boolean(
+                flag_key,
+                &tenant_id.to_string(),
+                &HashMap::new(),
+            )
+        } else {
+            Err(PostHogEvaluationError::NotAvailable(
+                "PostHog integration is not enabled".to_string(),
+            ))
+        }
+    }
+
+    pub fn is_feature_flag_boolean(&self, flag_key: &str) -> Result<bool, PostHogEvaluationError> {
+        if let Some(inner) = &self.inner {
+            inner.feature_store().is_feature_flag_boolean(flag_key)
+        } else {
+            Err(PostHogEvaluationError::NotAvailable(
+                "PostHog integration is not enabled".to_string(),
+            ))
+        }
+    }
+}
--- a/pageserver/src/http/openapi_spec.yml
+++ b/pageserver/src/http/openapi_spec.yml
@@ -353,6 +353,33 @@ paths:
        "200":
          description: OK

+  /v1/tenant/{tenant_shard_id}/timeline/{timeline_id}/mark_invisible:
+    parameters:
+      - name: tenant_shard_id
+        in: path
+        required: true
+        schema:
+          type: string
+      - name: timeline_id
+        in: path
+        required: true
+        schema:
+          type: string
+          format: hex
+    put:
+      requestBody:
+        content:
+          application/json:
+            schema:
+              type: object
+              properties:
+                is_visible:
+                  type: boolean
+                  default: false
+      responses:
+        "200":
+          description: OK
+
  /v1/tenant/{tenant_shard_id}/location_config:
    parameters:
      - name: tenant_shard_id
@@ -626,6 +653,8 @@ paths:
                  format: hex
                pg_version:
                  type: integer
+                read_only:
+                  type: boolean
                existing_initdb_timeline_id:
                  type: string
                  format: hex
--- a/pageserver/src/http/routes.rs
+++ b/pageserver/src/http/routes.rs
@@ -370,6 +370,18 @@ impl From<crate::tenant::secondary::SecondaryTenantError> for ApiError {
    }
 }

+impl From<crate::tenant::FinalizeTimelineImportError> for ApiError {
+    fn from(err: crate::tenant::FinalizeTimelineImportError) -> ApiError {
+        use crate::tenant::FinalizeTimelineImportError::*;
+        match err {
+            ImportTaskStillRunning => {
+                ApiError::ResourceUnavailable("Import task still running".into())
+            }
+            ShuttingDown => ApiError::ShuttingDown,
+        }
+    }
+}
+
 // Helper function to construct a TimelineInfo struct for a timeline
 async fn build_timeline_info(
    timeline: &Arc<Timeline>,
@@ -449,7 +461,7 @@ async fn build_timeline_info_common(
    // Internally we distinguish between the planned GC cutoff (PITR point) and the "applied" GC cutoff (where we
    // actually trimmed data to), which can pass each other when PITR is changed.
    let min_readable_lsn = std::cmp::max(
-        timeline.get_gc_cutoff_lsn(),
+        timeline.get_gc_cutoff_lsn().unwrap_or_default(),
        *timeline.get_applied_gc_cutoff_lsn(),
    );

@@ -572,6 +584,7 @@ async fn timeline_create_handler(
        TimelineCreateRequestMode::Branch {
            ancestor_timeline_id,
            ancestor_start_lsn,
+            read_only: _,
            pg_version: _,
        } => tenant::CreateTimelineParams::Branch(tenant::CreateTimelineParamsBranch {
            new_timeline_id,
@@ -3199,7 +3212,7 @@ async fn list_aux_files(
            .await?;

    let io_concurrency = IoConcurrency::spawn_from_conf(
-        state.conf,
+        state.conf.get_vectored_concurrent_io,
        timeline.gate.enter().map_err(|_| ApiError::Cancelled)?,
    );

@@ -3532,10 +3545,7 @@ async fn activate_post_import_handler(

        tenant.wait_to_become_active(ACTIVE_TENANT_TIMEOUT).await?;

-        tenant
-            .finalize_importing_timeline(timeline_id)
-            .await
-            .map_err(ApiError::InternalServerError)?;
+        tenant.finalize_importing_timeline(timeline_id).await?;

        match tenant.get_timeline(timeline_id, false) {
            Ok(_timeline) => {
@@ -3653,6 +3663,46 @@ async fn read_tar_eof(mut reader: (impl tokio::io::AsyncRead + Unpin)) -> anyhow
    Ok(())
 }

+async fn tenant_evaluate_feature_flag(
+    request: Request<Body>,
+    _cancel: CancellationToken,
+) -> Result<Response<Body>, ApiError> {
+    let tenant_shard_id: TenantShardId = parse_request_param(&request, "tenant_shard_id")?;
+    check_permission(&request, Some(tenant_shard_id.tenant_id))?;
+
+    let flag: String = must_parse_query_param(&request, "flag")?;
+    let as_type: String = must_parse_query_param(&request, "as")?;
+
+    let state = get_state(&request);
+
+    async {
+        let tenant = state
+            .tenant_manager
+            .get_attached_tenant_shard(tenant_shard_id)?;
+        if as_type == "boolean" {
+            let result = tenant.feature_resolver.evaluate_boolean(&flag, tenant_shard_id.tenant_id);
+            let result = result.map(|_| true).map_err(|e| e.to_string());
+            json_response(StatusCode::OK, result)
+        } else if as_type == "multivariate" {
+            let result = tenant.feature_resolver.evaluate_multivariate(&flag, tenant_shard_id.tenant_id).map_err(|e| e.to_string());
+            json_response(StatusCode::OK, result)
+        } else {
+            // Auto infer the type of the feature flag.
+            let is_boolean = tenant.feature_resolver.is_feature_flag_boolean(&flag).map_err(|e| ApiError::InternalServerError(anyhow::anyhow!("{e}")))?;
+            if is_boolean {
+                let result = tenant.feature_resolver.evaluate_boolean(&flag, tenant_shard_id.tenant_id);
+                let result = result.map(|_| true).map_err(|e| e.to_string());
+                json_response(StatusCode::OK, result)
+            } else {
+                let result = tenant.feature_resolver.evaluate_multivariate(&flag, tenant_shard_id.tenant_id).map_err(|e| e.to_string());
+                json_response(StatusCode::OK, result)
+            }
+        }
+    }
+    .instrument(info_span!("tenant_evaluate_feature_flag", tenant_id = %tenant_shard_id.tenant_id, shard_id = %tenant_shard_id.shard_slug()))
+    .await
+}
+
 /// Common functionality of all the HTTP API handlers.
 ///
 /// - Adds a tracing span to each request (by `request_span`)
@@ -4029,5 +4079,8 @@ pub fn make_router(
            "/v1/tenant/:tenant_shard_id/timeline/:timeline_id/activate_post_import",
            |r| api_handler(r, activate_post_import_handler),
        )
+        .get("/v1/tenant/:tenant_shard_id/feature_flag", |r| {
+            api_handler(r, tenant_evaluate_feature_flag)
+        })
        .any(handler_404))
 }
--- a/pageserver/src/lib.rs
+++ b/pageserver/src/lib.rs
@@ -3,12 +3,14 @@

 mod auth;
 pub mod basebackup;
+pub mod basebackup_cache;
 pub mod config;
 pub mod consumption_metrics;
 pub mod context;
 pub mod controller_upcall_client;
 pub mod deletion_queue;
 pub mod disk_usage_eviction_task;
+pub mod feature_resolver;
 pub mod http;
 pub mod import_datadir;
 pub mod l0_flush;
@@ -83,6 +85,7 @@ pub async fn shutdown_pageserver(
    http_listener: HttpEndpointListener,
    https_listener: Option<HttpsEndpointListener>,
    page_service: page_service::Listener,
+    grpc_task: Option<CancellableTask>,
    consumption_metrics_worker: ConsumptionMetricsTasks,
    disk_usage_eviction_task: Option<DiskUsageEvictionTask>,
    tenant_manager: &TenantManager,
@@ -176,6 +179,16 @@ pub async fn shutdown_pageserver(
    )
    .await;

+    // Shut down the gRPC server task, including request handlers.
+    if let Some(grpc_task) = grpc_task {
+        timed(
+            grpc_task.shutdown(),
+            "shutdown gRPC PageRequestHandler",
+            Duration::from_secs(3),
+        )
+        .await;
+    }
+
    // Shut down all the tenants. This flushes everything to disk and kills
    // the checkpoint and GC tasks.
    timed(
--- a/pageserver/src/metrics.rs
+++ b/pageserver/src/metrics.rs
@@ -843,23 +843,50 @@ pub(crate) static COMPRESSION_IMAGE_OUTPUT_BYTES: Lazy<IntCounter> = Lazy::new(|
    .expect("failed to define a metric")
 });

-pub(crate) static RELSIZE_CACHE_ENTRIES: Lazy<UIntGauge> = Lazy::new(|| {
+pub(crate) static RELSIZE_LATEST_CACHE_ENTRIES: Lazy<UIntGauge> = Lazy::new(|| {
    register_uint_gauge!(
-        "pageserver_relsize_cache_entries",
-        "Number of entries in the relation size cache",
+        "pageserver_relsize_latest_cache_entries",
+        "Number of entries in the latest relation size cache",
    )
    .expect("failed to define a metric")
 });

-pub(crate) static RELSIZE_CACHE_HITS: Lazy<IntCounter> = Lazy::new(|| {
-    register_int_counter!("pageserver_relsize_cache_hits", "Relation size cache hits",)
-        .expect("failed to define a metric")
+pub(crate) static RELSIZE_LATEST_CACHE_HITS: Lazy<IntCounter> = Lazy::new(|| {
+    register_int_counter!(
+        "pageserver_relsize_latest_cache_hits",
+        "Latest relation size cache hits",
+    )
+    .expect("failed to define a metric")
 });

-pub(crate) static RELSIZE_CACHE_MISSES: Lazy<IntCounter> = Lazy::new(|| {
+pub(crate) static RELSIZE_LATEST_CACHE_MISSES: Lazy<IntCounter> = Lazy::new(|| {
    register_int_counter!(
-        "pageserver_relsize_cache_misses",
-        "Relation size cache misses",
+        "pageserver_relsize_latest_cache_misses",
+        "Relation size latest cache misses",
+    )
+    .expect("failed to define a metric")
+});
+
+pub(crate) static RELSIZE_SNAPSHOT_CACHE_ENTRIES: Lazy<UIntGauge> = Lazy::new(|| {
+    register_uint_gauge!(
+        "pageserver_relsize_snapshot_cache_entries",
+        "Number of entries in the pitr relation size cache",
+    )
+    .expect("failed to define a metric")
+});
+
+pub(crate) static RELSIZE_SNAPSHOT_CACHE_HITS: Lazy<IntCounter> = Lazy::new(|| {
+    register_int_counter!(
+        "pageserver_relsize_snapshot_cache_hits",
+        "Pitr relation size cache hits",
+    )
+    .expect("failed to define a metric")
+});
+
+pub(crate) static RELSIZE_SNAPSHOT_CACHE_MISSES: Lazy<IntCounter> = Lazy::new(|| {
+    register_int_counter!(
+        "pageserver_relsize_snapshot_cache_misses",
+        "Relation size snapshot cache misses",
    )
    .expect("failed to define a metric")
 });
@@ -1039,6 +1066,15 @@ pub(crate) static TENANT_SYNTHETIC_SIZE_METRIC: Lazy<UIntGaugeVec> = Lazy::new(|
    .expect("Failed to register pageserver_tenant_synthetic_cached_size_bytes metric")
 });

+pub(crate) static TENANT_OFFLOADED_TIMELINES: Lazy<UIntGaugeVec> = Lazy::new(|| {
+    register_uint_gauge_vec!(
+        "pageserver_tenant_offloaded_timelines",
+        "Number of offloaded timelines of a tenant",
+        &["tenant_id", "shard_id"]
+    )
+    .expect("Failed to register pageserver_tenant_offloaded_timelines metric")
+});
+
 pub(crate) static EVICTION_ITERATION_DURATION: Lazy<HistogramVec> = Lazy::new(|| {
    register_histogram_vec!(
        "pageserver_eviction_iteration_duration_seconds_global",
@@ -1276,11 +1312,44 @@ impl EvictionsWithLowResidenceDuration {
 //
 // Roughly logarithmic scale.
 const STORAGE_IO_TIME_BUCKETS: &[f64] = &[
-    0.000030, // 30 usec
-    0.001000, // 1000 usec
-    0.030,    // 30 ms
-    1.000,    // 1000 ms
-    30.000,   // 30000 ms
+    0.00005,  // 50us
+    0.00006,  // 60us
+    0.00007,  // 70us
+    0.00008,  // 80us
+    0.00009,  // 90us
+    0.0001,   // 100us
+    0.000110, // 110us
+    0.000120, // 120us
+    0.000130, // 130us
+    0.000140, // 140us
+    0.000150, // 150us
+    0.000160, // 160us
+    0.000170, // 170us
+    0.000180, // 180us
+    0.000190, // 190us
+    0.000200, // 200us
+    0.000210, // 210us
+    0.000220, // 220us
+    0.000230, // 230us
+    0.000240, // 240us
+    0.000250, // 250us
+    0.000300, // 300us
+    0.000350, // 350us
+    0.000400, // 400us
+    0.000450, // 450us
+    0.000500, // 500us
+    0.000600, // 600us
+    0.000700, // 700us
+    0.000800, // 800us
+    0.000900, // 900us
+    0.001000, // 1ms
+    0.002000, // 2ms
+    0.003000, // 3ms
+    0.004000, // 4ms
+    0.005000, // 5ms
+    0.01000,  // 10ms
+    0.02000,  // 20ms
+    0.05000,  // 50ms
 ];

 /// VirtualFile fs operation variants.
@@ -2198,8 +2267,10 @@ impl BasebackupQueryTimeOngoingRecording<'_> {
        // If you want to change categorize of a specific error, also change it in `log_query_error`.
        let metric = match res {
            Ok(_) => &self.parent.ok,
-            Err(QueryError::Shutdown) => {
-                // Do not observe ok/err for shutdown
+            Err(QueryError::Shutdown) | Err(QueryError::Reconnect) => {
+                // Do not observe ok/err for shutdown/reconnect.
+                // Reconnect error might be raised when the operation is waiting for LSN and the tenant shutdown interrupts
+                // the operation. A reconnect error will be issued and the client will retry.
                return;
            }
            Err(QueryError::Disconnected(ConnectionError::Io(io_error)))
@@ -3524,11 +3595,14 @@ impl TimelineMetrics {
 }

 pub(crate) fn remove_tenant_metrics(tenant_shard_id: &TenantShardId) {
+    let tid = tenant_shard_id.tenant_id.to_string();
+    let shard_id = tenant_shard_id.shard_slug().to_string();
+
    // Only shard zero deals in synthetic sizes
    if tenant_shard_id.is_shard_zero() {
-        let tid = tenant_shard_id.tenant_id.to_string();
        let _ = TENANT_SYNTHETIC_SIZE_METRIC.remove_label_values(&[&tid]);
    }
+    let _ = TENANT_OFFLOADED_TIMELINES.remove_label_values(&[&tid, &shard_id]);

    tenant_throttling::remove_tenant_metrics(tenant_shard_id);

@@ -4320,6 +4394,42 @@ pub(crate) fn set_tokio_runtime_setup(setup: &str, num_threads: NonZeroUsize) {
        .set(u64::try_from(num_threads.get()).unwrap());
 }

+pub(crate) static BASEBACKUP_CACHE_READ: Lazy<IntCounterVec> = Lazy::new(|| {
+    register_int_counter_vec!(
+        "pageserver_basebackup_cache_read_total",
+        "Number of read accesses to the basebackup cache grouped by hit/miss/error",
+        &["result"]
+    )
+    .expect("failed to define a metric")
+});
+
+pub(crate) static BASEBACKUP_CACHE_PREPARE: Lazy<IntCounterVec> = Lazy::new(|| {
+    register_int_counter_vec!(
+        "pageserver_basebackup_cache_prepare_total",
+        "Number of prepare requests processed by the basebackup cache grouped by ok/skip/error",
+        &["result"]
+    )
+    .expect("failed to define a metric")
+});
+
+pub(crate) static BASEBACKUP_CACHE_ENTRIES: Lazy<IntGauge> = Lazy::new(|| {
+    register_int_gauge!(
+        "pageserver_basebackup_cache_entries_total",
+        "Number of entries in the basebackup cache"
+    )
+    .expect("failed to define a metric")
+});
+
+// FIXME: Support basebackup cache size metrics.
+#[allow(dead_code)]
+pub(crate) static BASEBACKUP_CACHE_SIZE: Lazy<IntGauge> = Lazy::new(|| {
+    register_int_gauge!(
+        "pageserver_basebackup_cache_size_bytes",
+        "Total size of all basebackup cache entries on disk in bytes"
+    )
+    .expect("failed to define a metric")
+});
+
 static PAGESERVER_CONFIG_IGNORED_ITEMS: Lazy<UIntGaugeVec> = Lazy::new(|| {
    register_uint_gauge_vec!(
        "pageserver_config_ignored_items",
--- a/pageserver/src/page_service.rs
+++ b/pageserver/src/page_service.rs
@@ -4,21 +4,21 @@
 use std::borrow::Cow;
 use std::num::NonZeroUsize;
 use std::os::fd::AsRawFd;
+use std::pin::Pin;
 use std::str::FromStr;
 use std::sync::Arc;
 use std::time::{Duration, Instant, SystemTime};
 use std::{io, str};

-use crate::PERF_TRACE_TARGET;
 use anyhow::{Context, bail};
 use async_compression::tokio::write::GzipEncoder;
 use bytes::Buf;
-use futures::FutureExt;
+use futures::{FutureExt, Stream};
 use itertools::Itertools;
 use jsonwebtoken::TokenData;
 use once_cell::sync::OnceCell;
 use pageserver_api::config::{
-    PageServicePipeliningConfig, PageServicePipeliningConfigPipelined,
+    GetVectoredConcurrentIo, PageServicePipeliningConfig, PageServicePipeliningConfigPipelined,
    PageServiceProtocolPipelinedBatchingStrategy, PageServiceProtocolPipelinedExecutionStrategy,
 };
 use pageserver_api::key::rel_block_to_key;
@@ -31,6 +31,7 @@ use pageserver_api::models::{
 };
 use pageserver_api::reltag::SlruKind;
 use pageserver_api::shard::TenantShardId;
+use pageserver_page_api::proto;
 use postgres_backend::{
    AuthType, PostgresBackend, PostgresBackendReader, QueryError, is_expected_io_error,
 };
@@ -42,18 +43,21 @@ use strum_macros::IntoStaticStr;
 use tokio::io::{AsyncRead, AsyncWrite, AsyncWriteExt, BufWriter};
 use tokio::task::JoinHandle;
 use tokio_util::sync::CancellationToken;
+use tonic::service::Interceptor as _;
 use tracing::*;
 use utils::auth::{Claims, Scope, SwappableJwtAuth};
 use utils::failpoint_support;
-use utils::id::{TenantId, TimelineId};
+use utils::id::{TenantId, TenantTimelineId, TimelineId};
 use utils::logging::log_slow;
 use utils::lsn::Lsn;
+use utils::shard::ShardIndex;
 use utils::simple_rcu::RcuReadGuard;
 use utils::sync::gate::{Gate, GateGuard};
 use utils::sync::spsc_fold;

 use crate::auth::check_permission;
-use crate::basebackup::BasebackupError;
+use crate::basebackup::{self, BasebackupError};
+use crate::basebackup_cache::BasebackupCache;
 use crate::config::PageServerConf;
 use crate::context::{
    DownloadBehavior, PerfInstrumentFutureExt, RequestContext, RequestContextBuilder,
@@ -62,7 +66,7 @@ use crate::metrics::{
    self, COMPUTE_COMMANDS_COUNTERS, ComputeCommandKind, GetPageBatchBreakReason, LIVE_CONNECTIONS,
    SmgrOpTimer, TimelineMetrics,
 };
-use crate::pgdatadir_mapping::Version;
+use crate::pgdatadir_mapping::{LsnRange, Version};
 use crate::span::{
    debug_assert_current_span_has_tenant_and_timeline_id,
    debug_assert_current_span_has_tenant_and_timeline_id_no_shard_id,
@@ -74,7 +78,7 @@ use crate::tenant::mgr::{
 use crate::tenant::storage_layer::IoConcurrency;
 use crate::tenant::timeline::{self, WaitLsnError};
 use crate::tenant::{GetTimelineError, PageReconstructError, Timeline};
-use crate::{basebackup, timed_after_cancellation};
+use crate::{CancellableTask, PERF_TRACE_TARGET, timed_after_cancellation};

 /// How long we may wait for a [`crate::tenant::mgr::TenantSlot::InProgress`]` and/or a [`crate::tenant::TenantShard`] which
 /// is not yet in state [`TenantState::Active`].
@@ -85,6 +89,26 @@ const ACTIVE_TENANT_TIMEOUT: Duration = Duration::from_millis(30000);
 /// Threshold at which to log slow GetPage requests.
 const LOG_SLOW_GETPAGE_THRESHOLD: Duration = Duration::from_secs(30);

+/// The idle time before sending TCP keepalive probes for gRPC connections. The
+/// interval and timeout between each probe is configured via sysctl. This
+/// allows detecting dead connections sooner.
+const GRPC_TCP_KEEPALIVE_TIME: Duration = Duration::from_secs(60);
+
+/// Whether to enable TCP nodelay for gRPC connections. This disables Nagle's
+/// algorithm, which can cause latency spikes for small messages.
+const GRPC_TCP_NODELAY: bool = true;
+
+/// The interval between HTTP2 keepalive pings. This allows shutting down server
+/// tasks when clients are unresponsive.
+const GRPC_HTTP2_KEEPALIVE_INTERVAL: Duration = Duration::from_secs(30);
+
+/// The timeout for HTTP2 keepalive pings. Should be <= GRPC_KEEPALIVE_INTERVAL.
+const GRPC_HTTP2_KEEPALIVE_TIMEOUT: Duration = Duration::from_secs(20);
+
+/// Number of concurrent gRPC streams per TCP connection. We expect something
+/// like 8 GetPage streams per connections, plus any unary requests.
+const GRPC_MAX_CONCURRENT_STREAMS: u32 = 256;
+
 ///////////////////////////////////////////////////////////////////////////////

 pub struct Listener {
@@ -107,6 +131,7 @@ pub fn spawn(
    perf_trace_dispatch: Option<Dispatch>,
    tcp_listener: tokio::net::TcpListener,
    tls_config: Option<Arc<rustls::ServerConfig>>,
+    basebackup_cache: Arc<BasebackupCache>,
 ) -> Listener {
    let cancel = CancellationToken::new();
    let libpq_ctx = RequestContext::todo_child(
@@ -128,6 +153,7 @@ pub fn spawn(
            conf.pg_auth_type,
            tls_config,
            conf.page_service_pipelining.clone(),
+            basebackup_cache,
            libpq_ctx,
            cancel.clone(),
        )
@@ -137,6 +163,94 @@ pub fn spawn(
    Listener { cancel, task }
 }

+/// Spawns a gRPC server for the page service.
+///
+/// TODO: this doesn't support TLS. We need TLS reloading via ReloadingCertificateResolver, so we
+/// need to reimplement the TCP+TLS accept loop ourselves.
+pub fn spawn_grpc(
+    conf: &'static PageServerConf,
+    tenant_manager: Arc<TenantManager>,
+    auth: Option<Arc<SwappableJwtAuth>>,
+    perf_trace_dispatch: Option<Dispatch>,
+    listener: std::net::TcpListener,
+    basebackup_cache: Arc<BasebackupCache>,
+) -> anyhow::Result<CancellableTask> {
+    let cancel = CancellationToken::new();
+    let ctx = RequestContextBuilder::new(TaskKind::PageRequestHandler)
+        .download_behavior(DownloadBehavior::Download)
+        .perf_span_dispatch(perf_trace_dispatch)
+        .detached_child();
+    let gate = Gate::default();
+
+    // Set up the TCP socket. We take a preconfigured TcpListener to bind the
+    // port early during startup.
+    let incoming = {
+        let _runtime = COMPUTE_REQUEST_RUNTIME.enter(); // required by TcpListener::from_std
+        listener.set_nonblocking(true)?;
+        tonic::transport::server::TcpIncoming::from(tokio::net::TcpListener::from_std(listener)?)
+            .with_nodelay(Some(GRPC_TCP_NODELAY))
+            .with_keepalive(Some(GRPC_TCP_KEEPALIVE_TIME))
+    };
+
+    // Set up the gRPC server.
+    //
+    // TODO: consider tuning window sizes.
+    // TODO: wire up tracing.
+    let mut server = tonic::transport::Server::builder()
+        .http2_keepalive_interval(Some(GRPC_HTTP2_KEEPALIVE_INTERVAL))
+        .http2_keepalive_timeout(Some(GRPC_HTTP2_KEEPALIVE_TIMEOUT))
+        .max_concurrent_streams(Some(GRPC_MAX_CONCURRENT_STREAMS));
+
+    // Main page service.
+    let page_service_handler = PageServerHandler::new(
+        tenant_manager,
+        auth.clone(),
+        PageServicePipeliningConfig::Serial, // TODO: unused with gRPC
+        conf.get_vectored_concurrent_io,
+        ConnectionPerfSpanFields::default(),
+        basebackup_cache,
+        ctx,
+        cancel.clone(),
+        gate.enter().expect("just created"),
+    );
+
+    let mut tenant_interceptor = TenantMetadataInterceptor;
+    let mut auth_interceptor = TenantAuthInterceptor::new(auth);
+    let interceptors = move |mut req: tonic::Request<()>| {
+        req = tenant_interceptor.call(req)?;
+        req = auth_interceptor.call(req)?;
+        Ok(req)
+    };
+
+    let page_service =
+        proto::PageServiceServer::with_interceptor(page_service_handler, interceptors);
+    let server = server.add_service(page_service);
+
+    // Reflection service for use with e.g. grpcurl.
+    let reflection_service = tonic_reflection::server::Builder::configure()
+        .register_encoded_file_descriptor_set(proto::FILE_DESCRIPTOR_SET)
+        .build_v1()?;
+    let server = server.add_service(reflection_service);
+
+    // Spawn server task.
+    let task_cancel = cancel.clone();
+    let task = COMPUTE_REQUEST_RUNTIME.spawn(task_mgr::exit_on_panic_or_error(
+        "grpc listener",
+        async move {
+            let result = server
+                .serve_with_incoming_shutdown(incoming, task_cancel.cancelled())
+                .await;
+            if result.is_ok() {
+                // TODO: revisit shutdown logic once page service is implemented.
+                gate.close().await;
+            }
+            result
+        },
+    ));
+
+    Ok(CancellableTask { task, cancel })
+}
+
 impl Listener {
    pub async fn stop_accepting(self) -> Connections {
        self.cancel.cancel();
@@ -186,6 +300,7 @@ pub async fn libpq_listener_main(
    auth_type: AuthType,
    tls_config: Option<Arc<rustls::ServerConfig>>,
    pipelining_config: PageServicePipeliningConfig,
+    basebackup_cache: Arc<BasebackupCache>,
    listener_ctx: RequestContext,
    listener_cancel: CancellationToken,
 ) -> Connections {
@@ -229,6 +344,7 @@ pub async fn libpq_listener_main(
                    auth_type,
                    tls_config.clone(),
                    pipelining_config.clone(),
+                    Arc::clone(&basebackup_cache),
                    connection_ctx,
                    connections_cancel.child_token(),
                    gate_guard,
@@ -254,7 +370,7 @@ type ConnectionHandlerResult = anyhow::Result<()>;

 /// Perf root spans start at the per-request level, after shard routing.
 /// This struct carries connection-level information to the root perf span definition.
-#[derive(Clone)]
+#[derive(Clone, Default)]
 struct ConnectionPerfSpanFields {
    peer_addr: String,
    application_name: Option<String>,
@@ -271,6 +387,7 @@ async fn page_service_conn_main(
    auth_type: AuthType,
    tls_config: Option<Arc<rustls::ServerConfig>>,
    pipelining_config: PageServicePipeliningConfig,
+    basebackup_cache: Arc<BasebackupCache>,
    connection_ctx: RequestContext,
    cancel: CancellationToken,
    gate_guard: GateGuard,
@@ -331,11 +448,12 @@ async fn page_service_conn_main(
    // But it's in a shared crate, so, we store connection_ctx inside PageServerHandler
    // and create the per-query context in process_query ourselves.
    let mut conn_handler = PageServerHandler::new(
-        conf,
        tenant_manager,
        auth,
        pipelining_config,
+        conf.get_vectored_concurrent_io,
        perf_span_fields,
+        basebackup_cache,
        connection_ctx,
        cancel.clone(),
        gate_guard,
@@ -370,8 +488,12 @@ async fn page_service_conn_main(
    }
 }

+/// Page service connection handler.
+///
+/// TODO: for gRPC, this will be shared by all requests from all connections.
+/// Decompose it into global state and per-connection/request state, and make
+/// libpq-specific options (e.g. pipelining) separate.
 struct PageServerHandler {
-    conf: &'static PageServerConf,
    auth: Option<Arc<SwappableJwtAuth>>,
    claims: Option<Claims>,

@@ -389,6 +511,9 @@ struct PageServerHandler {
    timeline_handles: Option<TimelineHandles>,

    pipelining_config: PageServicePipeliningConfig,
+    get_vectored_concurrent_io: GetVectoredConcurrentIo,
+
+    basebackup_cache: Arc<BasebackupCache>,

    gate_guard: GateGuard,
 }
@@ -642,8 +767,11 @@ impl std::fmt::Display for BatchedPageStreamError {
 struct BatchedGetPageRequest {
    req: PagestreamGetPageRequest,
    timer: SmgrOpTimer,
-    effective_request_lsn: Lsn,
+    lsn_range: LsnRange,
    ctx: RequestContext,
+    // If the request is perf enabled, this contains a context
+    // with a perf span tracking the time spent waiting for the executor.
+    batch_wait_ctx: Option<RequestContext>,
 }

 #[cfg(feature = "testing")]
@@ -656,6 +784,7 @@ struct BatchedTestRequest {
 /// so that we don't keep the [`Timeline::gate`] open while the batch
 /// is being built up inside the [`spsc_fold`] (pagestream pipelining).
 #[derive(IntoStaticStr)]
+#[allow(clippy::large_enum_variant)]
 enum BatchedFeMessage {
    Exists {
        span: Span,
@@ -764,12 +893,12 @@ impl BatchedFeMessage {
                match batching_strategy {
                    PageServiceProtocolPipelinedBatchingStrategy::UniformLsn => {
                        if let Some(last_in_batch) = accum_pages.last() {
-                            if last_in_batch.effective_request_lsn
-                                != this_pages[0].effective_request_lsn
+                            if last_in_batch.lsn_range.effective_lsn
+                                != this_pages[0].lsn_range.effective_lsn
                            {
                                trace!(
-                                    accum_lsn = %last_in_batch.effective_request_lsn,
-                                    this_lsn = %this_pages[0].effective_request_lsn,
+                                    accum_lsn = %last_in_batch.lsn_range.effective_lsn,
+                                    this_lsn = %this_pages[0].lsn_range.effective_lsn,
                                    "stopping batching because LSN changed"
                                );

@@ -784,15 +913,15 @@ impl BatchedFeMessage {
                        let same_page_different_lsn = accum_pages.iter().any(|batched| {
                            batched.req.rel == this_pages[0].req.rel
                                && batched.req.blkno == this_pages[0].req.blkno
-                                && batched.effective_request_lsn
-                                    != this_pages[0].effective_request_lsn
+                                && batched.lsn_range.effective_lsn
+                                    != this_pages[0].lsn_range.effective_lsn
                        });

                        if same_page_different_lsn {
                            trace!(
                                rel=%this_pages[0].req.rel,
                                blkno=%this_pages[0].req.blkno,
-                                lsn=%this_pages[0].effective_request_lsn,
+                                lsn=%this_pages[0].lsn_range.effective_lsn,
                                "stopping batching because same page was requested at different LSNs"
                            );

@@ -844,17 +973,17 @@ impl BatchedFeMessage {
 impl PageServerHandler {
    #[allow(clippy::too_many_arguments)]
    pub fn new(
-        conf: &'static PageServerConf,
        tenant_manager: Arc<TenantManager>,
        auth: Option<Arc<SwappableJwtAuth>>,
        pipelining_config: PageServicePipeliningConfig,
+        get_vectored_concurrent_io: GetVectoredConcurrentIo,
        perf_span_fields: ConnectionPerfSpanFields,
+        basebackup_cache: Arc<BasebackupCache>,
        connection_ctx: RequestContext,
        cancel: CancellationToken,
        gate_guard: GateGuard,
    ) -> Self {
        PageServerHandler {
-            conf,
            auth,
            claims: None,
            connection_ctx,
@@ -862,6 +991,8 @@ impl PageServerHandler {
            timeline_handles: Some(TimelineHandles::new(tenant_manager)),
            cancel,
            pipelining_config,
+            get_vectored_concurrent_io,
+            basebackup_cache,
            gate_guard,
        }
    }
@@ -1158,7 +1289,7 @@ impl PageServerHandler {
                .await?;

                // We're holding the Handle
-                let effective_request_lsn = match Self::effective_request_lsn(
+                let effective_lsn = match Self::effective_request_lsn(
                    &shard,
                    shard.get_last_record_lsn(),
                    req.hdr.request_lsn,
@@ -1171,14 +1302,34 @@ impl PageServerHandler {
                    }
                };

+                let batch_wait_ctx = if ctx.has_perf_span() {
+                    Some(
+                        RequestContextBuilder::from(&ctx)
+                            .perf_span(|crnt_perf_span| {
+                                info_span!(
+                                    target: PERF_TRACE_TARGET,
+                                    parent: crnt_perf_span,
+                                    "WAIT_EXECUTOR",
+                                )
+                            })
+                            .attached_child(),
+                    )
+                } else {
+                    None
+                };
+
                BatchedFeMessage::GetPage {
                    span,
                    shard: shard.downgrade(),
                    pages: smallvec::smallvec![BatchedGetPageRequest {
                        req,
                        timer,
-                        effective_request_lsn,
+                        lsn_range: LsnRange {
+                            effective_lsn,
+                            request_lsn: req.hdr.request_lsn
+                        },
                        ctx,
+                        batch_wait_ctx,
                    }],
                    // The executor grabs the batch when it becomes idle.
                    // Hence, [`GetPageBatchBreakReason::ExecutorSteal`] is the
@@ -1278,7 +1429,7 @@ impl PageServerHandler {
    }

    #[instrument(level = tracing::Level::DEBUG, skip_all)]
-    async fn pagesteam_handle_batched_message<IO>(
+    async fn pagestream_handle_batched_message<IO>(
        &mut self,
        pgb_writer: &mut PostgresBackend<IO>,
        batch: BatchedFeMessage,
@@ -1334,7 +1485,7 @@ impl PageServerHandler {
            let mut flush_timers = Vec::with_capacity(handler_results.len());
            for handler_result in &mut handler_results {
                let flush_timer = match handler_result {
-                    Ok((_, timer)) => Some(
+                    Ok((_response, timer, _ctx)) => Some(
                        timer
                            .observe_execution_end(flushing_start_time)
                            .expect("we are the first caller"),
@@ -1354,7 +1505,7 @@ impl PageServerHandler {
        // Some handler errors cause exit from pagestream protocol.
        // Other handler errors are sent back as an error message and we stay in pagestream protocol.
        for (handler_result, flushing_timer) in handler_results.into_iter().zip(flush_timers) {
-            let response_msg = match handler_result {
+            let (response_msg, ctx) = match handler_result {
                Err(e) => match &e.err {
                    PageStreamError::Shutdown => {
                        // If we fail to fulfil a request during shutdown, which may be _because_ of
@@ -1379,15 +1530,30 @@ impl PageServerHandler {
                            error!("error reading relation or page version: {full:#}")
                        });

-                        PagestreamBeMessage::Error(PagestreamErrorResponse {
-                            req: e.req,
-                            message: e.err.to_string(),
-                        })
+                        (
+                            PagestreamBeMessage::Error(PagestreamErrorResponse {
+                                req: e.req,
+                                message: e.err.to_string(),
+                            }),
+                            None,
+                        )
                    }
                },
-                Ok((response_msg, _op_timer_already_observed)) => response_msg,
+                Ok((response_msg, _op_timer_already_observed, ctx)) => (response_msg, Some(ctx)),
            };

+            let ctx = ctx.map(|req_ctx| {
+                RequestContextBuilder::from(&req_ctx)
+                    .perf_span(|crnt_perf_span| {
+                        info_span!(
+                            target: PERF_TRACE_TARGET,
+                            parent: crnt_perf_span,
+                            "FLUSH_RESPONSE",
+                        )
+                    })
+                    .attached_child()
+            });
+
            //
            // marshal & transmit response message
            //
@@ -1410,6 +1576,17 @@ impl PageServerHandler {
                )),
                None => futures::future::Either::Right(flush_fut),
            };
+
+            let flush_fut = if let Some(req_ctx) = ctx.as_ref() {
+                futures::future::Either::Left(
+                    flush_fut.maybe_perf_instrument(req_ctx, |current_perf_span| {
+                        current_perf_span.clone()
+                    }),
+                )
+            } else {
+                futures::future::Either::Right(flush_fut)
+            };
+
            // do it while respecting cancellation
            let _: () = async move {
                tokio::select! {
@@ -1439,7 +1616,7 @@ impl PageServerHandler {
        ctx: &RequestContext,
    ) -> Result<
        (
-            Vec<Result<(PagestreamBeMessage, SmgrOpTimer), BatchedPageStreamError>>,
+            Vec<Result<(PagestreamBeMessage, SmgrOpTimer, RequestContext), BatchedPageStreamError>>,
            Span,
        ),
        QueryError,
@@ -1466,7 +1643,7 @@ impl PageServerHandler {
                        self.handle_get_rel_exists_request(&shard, &req, &ctx)
                            .instrument(span.clone())
                            .await
-                            .map(|msg| (msg, timer))
+                            .map(|msg| (msg, timer, ctx))
                            .map_err(|err| BatchedPageStreamError { err, req: req.hdr }),
                    ],
                    span,
@@ -1485,7 +1662,7 @@ impl PageServerHandler {
                        self.handle_get_nblocks_request(&shard, &req, &ctx)
                            .instrument(span.clone())
                            .await
-                            .map(|msg| (msg, timer))
+                            .map(|msg| (msg, timer, ctx))
                            .map_err(|err| BatchedPageStreamError { err, req: req.hdr }),
                    ],
                    span,
@@ -1532,7 +1709,7 @@ impl PageServerHandler {
                        self.handle_db_size_request(&shard, &req, &ctx)
                            .instrument(span.clone())
                            .await
-                            .map(|msg| (msg, timer))
+                            .map(|msg| (msg, timer, ctx))
                            .map_err(|err| BatchedPageStreamError { err, req: req.hdr }),
                    ],
                    span,
@@ -1551,7 +1728,7 @@ impl PageServerHandler {
                        self.handle_get_slru_segment_request(&shard, &req, &ctx)
                            .instrument(span.clone())
                            .await
-                            .map(|msg| (msg, timer))
+                            .map(|msg| (msg, timer, ctx))
                            .map_err(|err| BatchedPageStreamError { err, req: req.hdr }),
                    ],
                    span,
@@ -1623,7 +1800,7 @@ impl PageServerHandler {
        }

        let io_concurrency = IoConcurrency::spawn_from_conf(
-            self.conf,
+            self.get_vectored_concurrent_io,
            match self.gate_guard.try_clone() {
                Ok(guard) => guard,
                Err(_) => {
@@ -1733,7 +1910,7 @@ impl PageServerHandler {
            };

            let result = self
-                .pagesteam_handle_batched_message(
+                .pagestream_handle_batched_message(
                    pgb_writer,
                    msg,
                    io_concurrency.clone(),
@@ -1903,13 +2080,26 @@ impl PageServerHandler {
                            return Ok(());
                        }
                    };
-                    let batch = match batch {
+                    let mut batch = match batch {
                        Ok(batch) => batch,
                        Err(e) => {
                            return Err(e);
                        }
                    };
-                    self.pagesteam_handle_batched_message(
+
+                    if let BatchedFeMessage::GetPage {
+                        pages,
+                        span: _,
+                        shard: _,
+                        batch_break_reason: _,
+                    } = &mut batch
+                    {
+                        for req in pages {
+                            req.batch_wait_ctx.take();
+                        }
+                    }
+
+                    self.pagestream_handle_batched_message(
                        pgb_writer,
                        batch,
                        io_concurrency.clone(),
@@ -2127,7 +2317,14 @@ impl PageServerHandler {
        .await?;

        let exists = timeline
-            .get_rel_exists(req.rel, Version::Lsn(lsn), ctx)
+            .get_rel_exists(
+                req.rel,
+                Version::LsnRange(LsnRange {
+                    effective_lsn: lsn,
+                    request_lsn: req.hdr.request_lsn,
+                }),
+                ctx,
+            )
            .await?;

        Ok(PagestreamBeMessage::Exists(PagestreamExistsResponse {
@@ -2154,7 +2351,14 @@ impl PageServerHandler {
        .await?;

        let n_blocks = timeline
-            .get_rel_size(req.rel, Version::Lsn(lsn), ctx)
+            .get_rel_size(
+                req.rel,
+                Version::LsnRange(LsnRange {
+                    effective_lsn: lsn,
+                    request_lsn: req.hdr.request_lsn,
+                }),
+                ctx,
+            )
            .await?;

        Ok(PagestreamBeMessage::Nblocks(PagestreamNblocksResponse {
@@ -2181,7 +2385,15 @@ impl PageServerHandler {
        .await?;

        let total_blocks = timeline
-            .get_db_size(DEFAULTTABLESPACE_OID, req.dbnode, Version::Lsn(lsn), ctx)
+            .get_db_size(
+                DEFAULTTABLESPACE_OID,
+                req.dbnode,
+                Version::LsnRange(LsnRange {
+                    effective_lsn: lsn,
+                    request_lsn: req.hdr.request_lsn,
+                }),
+                ctx,
+            )
            .await?;
        let db_size = total_blocks as i64 * BLCKSZ as i64;

@@ -2199,7 +2411,8 @@ impl PageServerHandler {
        io_concurrency: IoConcurrency,
        batch_break_reason: GetPageBatchBreakReason,
        ctx: &RequestContext,
-    ) -> Vec<Result<(PagestreamBeMessage, SmgrOpTimer), BatchedPageStreamError>> {
+    ) -> Vec<Result<(PagestreamBeMessage, SmgrOpTimer, RequestContext), BatchedPageStreamError>>
+    {
        debug_assert_current_span_has_tenant_and_timeline_id();

        timeline
@@ -2214,7 +2427,7 @@ impl PageServerHandler {
                // Ignore error (trace buffer may be full or tracer may have disconnected).
                _ = page_trace.try_send(PageTraceEvent {
                    key,
-                    effective_lsn: batch.effective_request_lsn,
+                    effective_lsn: batch.lsn_range.effective_lsn,
                    time,
                });
            }
@@ -2229,7 +2442,7 @@ impl PageServerHandler {
                    perf_instrument = true;
                }

-                req.effective_request_lsn
+                req.lsn_range.effective_lsn
            })
            .max()
            .expect("batch is never empty");
@@ -2283,7 +2496,7 @@ impl PageServerHandler {
                    (
                        &p.req.rel,
                        &p.req.blkno,
-                        p.effective_request_lsn,
+                        p.lsn_range,
                        p.ctx.attached_child(),
                    )
                }),
@@ -2306,6 +2519,7 @@ impl PageServerHandler {
                                page,
                            }),
                            req.timer,
+                            req.ctx,
                        )
                    })
                    .map_err(|e| BatchedPageStreamError {
@@ -2350,7 +2564,8 @@ impl PageServerHandler {
        timeline: &Timeline,
        requests: Vec<BatchedTestRequest>,
        _ctx: &RequestContext,
-    ) -> Vec<Result<(PagestreamBeMessage, SmgrOpTimer), BatchedPageStreamError>> {
+    ) -> Vec<Result<(PagestreamBeMessage, SmgrOpTimer, RequestContext), BatchedPageStreamError>>
+    {
        // real requests would do something with the timeline
        let mut results = Vec::with_capacity(requests.len());
        for _req in requests.iter() {
@@ -2377,6 +2592,10 @@ impl PageServerHandler {
                                req: req.req.clone(),
                            }),
                            req.timer,
+                            RequestContext::new(
+                                TaskKind::PageRequestHandler,
+                                DownloadBehavior::Warn,
+                            ),
                        )
                    })
                    .map_err(|e| BatchedPageStreamError {
@@ -2468,6 +2687,8 @@ impl PageServerHandler {
            .map_err(QueryError::Disconnected)?;
        self.flush_cancellable(pgb, &self.cancel).await?;

+        let mut from_cache = false;
+
        // Send a tarball of the latest layer on the timeline. Compress if not
        // fullbackup. TODO Compress in that case too (tests need to be updated)
        if full_backup {
@@ -2485,7 +2706,33 @@ impl PageServerHandler {
            .map_err(map_basebackup_error)?;
        } else {
            let mut writer = BufWriter::new(pgb.copyout_writer());
-            if gzip {
+
+            let cached = {
+                // Basebackup is cached only for this combination of parameters.
+                if timeline.is_basebackup_cache_enabled()
+                    && gzip
+                    && lsn.is_some()
+                    && prev_lsn.is_none()
+                {
+                    self.basebackup_cache
+                        .get(tenant_id, timeline_id, lsn.unwrap())
+                        .await
+                } else {
+                    None
+                }
+            };
+
+            if let Some(mut cached) = cached {
+                from_cache = true;
+                tokio::io::copy(&mut cached, &mut writer)
+                    .await
+                    .map_err(|e| {
+                        map_basebackup_error(BasebackupError::Client(
+                            e,
+                            "handle_basebackup_request,cached,copy",
+                        ))
+                    })?;
+            } else if gzip {
                let mut encoder = GzipEncoder::with_quality(
                    &mut writer,
                    // NOTE using fast compression because it's on the critical path
@@ -2544,6 +2791,7 @@ impl PageServerHandler {
        info!(
            lsn_await_millis = lsn_awaited_after.as_millis(),
            basebackup_millis = basebackup_after.as_millis(),
+            %from_cache,
            "basebackup complete"
        );

@@ -3052,6 +3300,60 @@ where
    }
 }

+/// Implements the page service over gRPC.
+///
+/// TODO: not yet implemented, all methods return unimplemented.
+#[tonic::async_trait]
+impl proto::PageService for PageServerHandler {
+    type GetBaseBackupStream = Pin<
+        Box<dyn Stream<Item = Result<proto::GetBaseBackupResponseChunk, tonic::Status>> + Send>,
+    >;
+    type GetPagesStream =
+        Pin<Box<dyn Stream<Item = Result<proto::GetPageResponse, tonic::Status>> + Send>>;
+
+    async fn check_rel_exists(
+        &self,
+        _: tonic::Request<proto::CheckRelExistsRequest>,
+    ) -> Result<tonic::Response<proto::CheckRelExistsResponse>, tonic::Status> {
+        Err(tonic::Status::unimplemented("not implemented"))
+    }
+
+    async fn get_base_backup(
+        &self,
+        _: tonic::Request<proto::GetBaseBackupRequest>,
+    ) -> Result<tonic::Response<Self::GetBaseBackupStream>, tonic::Status> {
+        Err(tonic::Status::unimplemented("not implemented"))
+    }
+
+    async fn get_db_size(
+        &self,
+        _: tonic::Request<proto::GetDbSizeRequest>,
+    ) -> Result<tonic::Response<proto::GetDbSizeResponse>, tonic::Status> {
+        Err(tonic::Status::unimplemented("not implemented"))
+    }
+
+    async fn get_pages(
+        &self,
+        _: tonic::Request<tonic::Streaming<proto::GetPageRequest>>,
+    ) -> Result<tonic::Response<Self::GetPagesStream>, tonic::Status> {
+        Err(tonic::Status::unimplemented("not implemented"))
+    }
+
+    async fn get_rel_size(
+        &self,
+        _: tonic::Request<proto::GetRelSizeRequest>,
+    ) -> Result<tonic::Response<proto::GetRelSizeResponse>, tonic::Status> {
+        Err(tonic::Status::unimplemented("not implemented"))
+    }
+
+    async fn get_slru_segment(
+        &self,
+        _: tonic::Request<proto::GetSlruSegmentRequest>,
+    ) -> Result<tonic::Response<proto::GetSlruSegmentResponse>, tonic::Status> {
+        Err(tonic::Status::unimplemented("not implemented"))
+    }
+}
+
 impl From<GetActiveTenantError> for QueryError {
    fn from(e: GetActiveTenantError) -> Self {
        match e {
@@ -3068,6 +3370,104 @@ impl From<GetActiveTenantError> for QueryError {
    }
 }

+/// gRPC interceptor that decodes tenant metadata and stores it as request extensions of type
+/// TenantTimelineId and ShardIndex.
+///
+/// TODO: consider looking up the timeline handle here and storing it.
+#[derive(Clone)]
+struct TenantMetadataInterceptor;
+
+impl tonic::service::Interceptor for TenantMetadataInterceptor {
+    fn call(&mut self, mut req: tonic::Request<()>) -> Result<tonic::Request<()>, tonic::Status> {
+        // Decode the tenant ID.
+        let tenant_id = req
+            .metadata()
+            .get("neon-tenant-id")
+            .ok_or_else(|| tonic::Status::invalid_argument("missing neon-tenant-id"))?
+            .to_str()
+            .map_err(|_| tonic::Status::invalid_argument("invalid neon-tenant-id"))?;
+        let tenant_id = TenantId::from_str(tenant_id)
+            .map_err(|_| tonic::Status::invalid_argument("invalid neon-tenant-id"))?;
+
+        // Decode the timeline ID.
+        let timeline_id = req
+            .metadata()
+            .get("neon-timeline-id")
+            .ok_or_else(|| tonic::Status::invalid_argument("missing neon-timeline-id"))?
+            .to_str()
+            .map_err(|_| tonic::Status::invalid_argument("invalid neon-timeline-id"))?;
+        let timeline_id = TimelineId::from_str(timeline_id)
+            .map_err(|_| tonic::Status::invalid_argument("invalid neon-timeline-id"))?;
+
+        // Decode the shard ID.
+        let shard_index = req
+            .metadata()
+            .get("neon-shard-id")
+            .ok_or_else(|| tonic::Status::invalid_argument("missing neon-shard-id"))?
+            .to_str()
+            .map_err(|_| tonic::Status::invalid_argument("invalid neon-shard-id"))?;
+        let shard_index = ShardIndex::from_str(shard_index)
+            .map_err(|_| tonic::Status::invalid_argument("invalid neon-shard-id"))?;
+
+        // Stash them in the request.
+        let extensions = req.extensions_mut();
+        extensions.insert(TenantTimelineId::new(tenant_id, timeline_id));
+        extensions.insert(shard_index);
+
+        Ok(req)
+    }
+}
+
+/// Authenticates gRPC page service requests. Must run after TenantMetadataInterceptor.
+#[derive(Clone)]
+struct TenantAuthInterceptor {
+    auth: Option<Arc<SwappableJwtAuth>>,
+}
+
+impl TenantAuthInterceptor {
+    fn new(auth: Option<Arc<SwappableJwtAuth>>) -> Self {
+        Self { auth }
+    }
+}
+
+impl tonic::service::Interceptor for TenantAuthInterceptor {
+    fn call(&mut self, req: tonic::Request<()>) -> Result<tonic::Request<()>, tonic::Status> {
+        // Do nothing if auth is disabled.
+        let Some(auth) = self.auth.as_ref() else {
+            return Ok(req);
+        };
+
+        // Fetch the tenant ID that's been set by TenantMetadataInterceptor.
+        let ttid = req
+            .extensions()
+            .get::<TenantTimelineId>()
+            .expect("TenantMetadataInterceptor must run before TenantAuthInterceptor");
+
+        // Fetch and decode the JWT token.
+        let jwt = req
+            .metadata()
+            .get("authorization")
+            .ok_or_else(|| tonic::Status::unauthenticated("no authorization header"))?
+            .to_str()
+            .map_err(|_| tonic::Status::invalid_argument("invalid authorization header"))?
+            .strip_prefix("Bearer ")
+            .ok_or_else(|| tonic::Status::invalid_argument("invalid authorization header"))?
+            .trim();
+        let jwtdata: TokenData<Claims> = auth
+            .decode(jwt)
+            .map_err(|err| tonic::Status::invalid_argument(format!("invalid JWT token: {err}")))?;
+        let claims = jwtdata.claims;
+
+        // Check if the token is valid for this tenant.
+        check_permission(&claims, Some(ttid.tenant_id))
+            .map_err(|err| tonic::Status::permission_denied(err.to_string()))?;
+
+        // TODO: consider stashing the claims in the request extensions, if needed.
+
+        Ok(req)
+    }
+}
+
 #[derive(Debug, thiserror::Error)]
 pub(crate) enum GetActiveTimelineError {
    #[error(transparent)]
--- a/pageserver/src/pgdatadir_mapping.rs
+++ b/pageserver/src/pgdatadir_mapping.rs
@@ -43,7 +43,9 @@ use crate::aux_file;
 use crate::context::{PerfInstrumentFutureExt, RequestContext, RequestContextBuilder};
 use crate::keyspace::{KeySpace, KeySpaceAccum};
 use crate::metrics::{
-    RELSIZE_CACHE_ENTRIES, RELSIZE_CACHE_HITS, RELSIZE_CACHE_MISSES, RELSIZE_CACHE_MISSES_OLD,
+    RELSIZE_CACHE_MISSES_OLD, RELSIZE_LATEST_CACHE_ENTRIES, RELSIZE_LATEST_CACHE_HITS,
+    RELSIZE_LATEST_CACHE_MISSES, RELSIZE_SNAPSHOT_CACHE_ENTRIES, RELSIZE_SNAPSHOT_CACHE_HITS,
+    RELSIZE_SNAPSHOT_CACHE_MISSES,
 };
 use crate::span::{
    debug_assert_current_span_has_tenant_and_timeline_id,
@@ -90,6 +92,28 @@ pub enum LsnForTimestamp {
    NoData(Lsn),
 }

+/// Each request to page server contains LSN range: `not_modified_since..request_lsn`.
+/// See comments libs/pageserver_api/src/models.rs.
+/// Based on this range and `last_record_lsn` PS calculates `effective_lsn`.
+/// But to distinguish requests from primary and replicas we need also to pass `request_lsn`.
+#[derive(Debug, Clone, Copy, Default)]
+pub struct LsnRange {
+    pub effective_lsn: Lsn,
+    pub request_lsn: Lsn,
+}
+
+impl LsnRange {
+    pub fn at(lsn: Lsn) -> LsnRange {
+        LsnRange {
+            effective_lsn: lsn,
+            request_lsn: lsn,
+        }
+    }
+    pub fn is_latest(&self) -> bool {
+        self.request_lsn == Lsn::MAX
+    }
+}
+
 #[derive(Debug, thiserror::Error)]
 pub(crate) enum CalculateLogicalSizeError {
    #[error("cancelled")]
@@ -202,13 +226,13 @@ impl Timeline {
        io_concurrency: IoConcurrency,
    ) -> Result<Bytes, PageReconstructError> {
        match version {
-            Version::Lsn(effective_lsn) => {
+            Version::LsnRange(lsns) => {
                let pages: smallvec::SmallVec<[_; 1]> = smallvec::smallvec![(tag, blknum)];
                let res = self
                    .get_rel_page_at_lsn_batched(
-                        pages.iter().map(|(tag, blknum)| {
-                            (tag, blknum, effective_lsn, ctx.attached_child())
-                        }),
+                        pages
+                            .iter()
+                            .map(|(tag, blknum)| (tag, blknum, lsns, ctx.attached_child())),
                        io_concurrency.clone(),
                        ctx,
                    )
@@ -246,7 +270,7 @@ impl Timeline {
    /// The ordering of the returned vec corresponds to the ordering of `pages`.
    pub(crate) async fn get_rel_page_at_lsn_batched(
        &self,
-        pages: impl ExactSizeIterator<Item = (&RelTag, &BlockNumber, Lsn, RequestContext)>,
+        pages: impl ExactSizeIterator<Item = (&RelTag, &BlockNumber, LsnRange, RequestContext)>,
        io_concurrency: IoConcurrency,
        ctx: &RequestContext,
    ) -> Vec<Result<Bytes, PageReconstructError>> {
@@ -265,7 +289,7 @@ impl Timeline {
        let mut req_keyspaces: HashMap<Lsn, KeySpaceRandomAccum> =
            HashMap::with_capacity(pages.len());

-        for (response_slot_idx, (tag, blknum, lsn, ctx)) in pages.enumerate() {
+        for (response_slot_idx, (tag, blknum, lsns, ctx)) in pages.enumerate() {
            if tag.relnode == 0 {
                result_slots[response_slot_idx].write(Err(PageReconstructError::Other(
                    RelationError::InvalidRelnode.into(),
@@ -274,7 +298,7 @@ impl Timeline {
                slots_filled += 1;
                continue;
            }
-
+            let lsn = lsns.effective_lsn;
            let nblocks = {
                let ctx = RequestContextBuilder::from(&ctx)
                    .perf_span(|crnt_perf_span| {
@@ -289,7 +313,7 @@ impl Timeline {
                    .attached_child();

                match self
-                    .get_rel_size(*tag, Version::Lsn(lsn), &ctx)
+                    .get_rel_size(*tag, Version::LsnRange(lsns), &ctx)
                    .maybe_perf_instrument(&ctx, |crnt_perf_span| crnt_perf_span.clone())
                    .await
                {
@@ -470,7 +494,7 @@ impl Timeline {
            ));
        }

-        if let Some(nblocks) = self.get_cached_rel_size(&tag, version.get_lsn()) {
+        if let Some(nblocks) = self.get_cached_rel_size(&tag, version) {
            return Ok(nblocks);
        }

@@ -488,7 +512,7 @@ impl Timeline {
        let mut buf = version.get(self, key, ctx).await?;
        let nblocks = buf.get_u32_le();

-        self.update_cached_rel_size(tag, version.get_lsn(), nblocks);
+        self.update_cached_rel_size(tag, version, nblocks);

        Ok(nblocks)
    }
@@ -510,7 +534,7 @@ impl Timeline {
        }

        // first try to lookup relation in cache
-        if let Some(_nblocks) = self.get_cached_rel_size(&tag, version.get_lsn()) {
+        if let Some(_nblocks) = self.get_cached_rel_size(&tag, version) {
            return Ok(true);
        }
        // then check if the database was already initialized.
@@ -586,7 +610,7 @@ impl Timeline {
        // scan directory listing (new), merge with the old results
        let key_range = rel_tag_sparse_key_range(spcnode, dbnode);
        let io_concurrency = IoConcurrency::spawn_from_conf(
-            self.conf,
+            self.conf.get_vectored_concurrent_io,
            self.gate
                .enter()
                .map_err(|_| PageReconstructError::Cancelled)?,
@@ -632,7 +656,7 @@ impl Timeline {
    ) -> Result<Bytes, PageReconstructError> {
        assert!(self.tenant_shard_id.is_shard_zero());
        let n_blocks = self
-            .get_slru_segment_size(kind, segno, Version::Lsn(lsn), ctx)
+            .get_slru_segment_size(kind, segno, Version::at(lsn), ctx)
            .await?;

        let keyspace = KeySpace::single(
@@ -645,7 +669,7 @@ impl Timeline {
        );

        let io_concurrency = IoConcurrency::spawn_from_conf(
-            self.conf,
+            self.conf.get_vectored_concurrent_io,
            self.gate
                .enter()
                .map_err(|_| PageReconstructError::Cancelled)?,
@@ -867,11 +891,11 @@ impl Timeline {
        mut f: impl FnMut(TimestampTz) -> ControlFlow<T>,
    ) -> Result<T, PageReconstructError> {
        for segno in self
-            .list_slru_segments(SlruKind::Clog, Version::Lsn(probe_lsn), ctx)
+            .list_slru_segments(SlruKind::Clog, Version::at(probe_lsn), ctx)
            .await?
        {
            let nblocks = self
-                .get_slru_segment_size(SlruKind::Clog, segno, Version::Lsn(probe_lsn), ctx)
+                .get_slru_segment_size(SlruKind::Clog, segno, Version::at(probe_lsn), ctx)
                .await?;

            let keyspace = KeySpace::single(
@@ -885,7 +909,7 @@ impl Timeline {
            );

            let io_concurrency = IoConcurrency::spawn_from_conf(
-                self.conf,
+                self.conf.get_vectored_concurrent_io,
                self.gate
                    .enter()
                    .map_err(|_| PageReconstructError::Cancelled)?,
@@ -1137,7 +1161,7 @@ impl Timeline {
        let mut total_size: u64 = 0;
        for (spcnode, dbnode) in dbdir.dbdirs.keys() {
            for rel in self
-                .list_rels(*spcnode, *dbnode, Version::Lsn(lsn), ctx)
+                .list_rels(*spcnode, *dbnode, Version::at(lsn), ctx)
                .await?
            {
                if self.cancel.is_cancelled() {
@@ -1212,7 +1236,7 @@ impl Timeline {
            result.add_key(rel_dir_to_key(spcnode, dbnode));

            let mut rels: Vec<RelTag> = self
-                .list_rels(spcnode, dbnode, Version::Lsn(lsn), ctx)
+                .list_rels(spcnode, dbnode, Version::at(lsn), ctx)
                .await?
                .into_iter()
                .collect();
@@ -1329,59 +1353,75 @@ impl Timeline {
        Ok((dense_keyspace, sparse_keyspace))
    }

-    /// Get cached size of relation if it not updated after specified LSN
-    pub fn get_cached_rel_size(&self, tag: &RelTag, lsn: Lsn) -> Option<BlockNumber> {
-        let rel_size_cache = self.rel_size_cache.read().unwrap();
-        if let Some((cached_lsn, nblocks)) = rel_size_cache.map.get(tag) {
-            if lsn >= *cached_lsn {
-                RELSIZE_CACHE_HITS.inc();
-                return Some(*nblocks);
+    /// Get cached size of relation. There are two caches: one for primary updates, it captures the latest state of
+    /// of the timeline and snapshot cache, which key includes LSN and so can be used by replicas to get relation size
+    /// at the particular LSN (snapshot).
+    pub fn get_cached_rel_size(&self, tag: &RelTag, version: Version<'_>) -> Option<BlockNumber> {
+        let lsn = version.get_lsn();
+        {
+            let rel_size_cache = self.rel_size_latest_cache.read().unwrap();
+            if let Some((cached_lsn, nblocks)) = rel_size_cache.get(tag) {
+                if lsn >= *cached_lsn {
+                    RELSIZE_LATEST_CACHE_HITS.inc();
+                    return Some(*nblocks);
+                }
+                RELSIZE_CACHE_MISSES_OLD.inc();
            }
-            RELSIZE_CACHE_MISSES_OLD.inc();
        }
-        RELSIZE_CACHE_MISSES.inc();
+        {
+            let mut rel_size_cache = self.rel_size_snapshot_cache.lock().unwrap();
+            if let Some(nblock) = rel_size_cache.get(&(lsn, *tag)) {
+                RELSIZE_SNAPSHOT_CACHE_HITS.inc();
+                return Some(*nblock);
+            }
+        }
+        if version.is_latest() {
+            RELSIZE_LATEST_CACHE_MISSES.inc();
+        } else {
+            RELSIZE_SNAPSHOT_CACHE_MISSES.inc();
+        }
        None
    }

    /// Update cached relation size if there is no more recent update
-    pub fn update_cached_rel_size(&self, tag: RelTag, lsn: Lsn, nblocks: BlockNumber) {
-        let mut rel_size_cache = self.rel_size_cache.write().unwrap();
-
-        if lsn < rel_size_cache.complete_as_of {
-            // Do not cache old values. It's safe to cache the size on read, as long as
-            // the read was at an LSN since we started the WAL ingestion. Reasoning: we
-            // never evict values from the cache, so if the relation size changed after
-            // 'lsn', the new value is already in the cache.
-            return;
-        }
-
-        match rel_size_cache.map.entry(tag) {
-            hash_map::Entry::Occupied(mut entry) => {
-                let cached_lsn = entry.get_mut();
-                if lsn >= cached_lsn.0 {
-                    *cached_lsn = (lsn, nblocks);
+    pub fn update_cached_rel_size(&self, tag: RelTag, version: Version<'_>, nblocks: BlockNumber) {
+        let lsn = version.get_lsn();
+        if version.is_latest() {
+            let mut rel_size_cache = self.rel_size_latest_cache.write().unwrap();
+            match rel_size_cache.entry(tag) {
+                hash_map::Entry::Occupied(mut entry) => {
+                    let cached_lsn = entry.get_mut();
+                    if lsn >= cached_lsn.0 {
+                        *cached_lsn = (lsn, nblocks);
+                    }
+                }
+                hash_map::Entry::Vacant(entry) => {
+                    entry.insert((lsn, nblocks));
+                    RELSIZE_LATEST_CACHE_ENTRIES.inc();
                }
            }
-            hash_map::Entry::Vacant(entry) => {
-                entry.insert((lsn, nblocks));
-                RELSIZE_CACHE_ENTRIES.inc();
+        } else {
+            let mut rel_size_cache = self.rel_size_snapshot_cache.lock().unwrap();
+            if rel_size_cache.capacity() != 0 {
+                rel_size_cache.insert((lsn, tag), nblocks);
+                RELSIZE_SNAPSHOT_CACHE_ENTRIES.set(rel_size_cache.len() as u64);
            }
        }
    }

    /// Store cached relation size
    pub fn set_cached_rel_size(&self, tag: RelTag, lsn: Lsn, nblocks: BlockNumber) {
-        let mut rel_size_cache = self.rel_size_cache.write().unwrap();
-        if rel_size_cache.map.insert(tag, (lsn, nblocks)).is_none() {
-            RELSIZE_CACHE_ENTRIES.inc();
+        let mut rel_size_cache = self.rel_size_latest_cache.write().unwrap();
+        if rel_size_cache.insert(tag, (lsn, nblocks)).is_none() {
+            RELSIZE_LATEST_CACHE_ENTRIES.inc();
        }
    }

    /// Remove cached relation size
    pub fn remove_cached_rel_size(&self, tag: &RelTag) {
-        let mut rel_size_cache = self.rel_size_cache.write().unwrap();
-        if rel_size_cache.map.remove(tag).is_some() {
-            RELSIZE_CACHE_ENTRIES.dec();
+        let mut rel_size_cache = self.rel_size_latest_cache.write().unwrap();
+        if rel_size_cache.remove(tag).is_some() {
+            RELSIZE_LATEST_CACHE_ENTRIES.dec();
        }
    }
 }
@@ -1585,7 +1625,10 @@ impl DatadirModification<'_> {
        //       check the cache too. This is because eagerly checking the cache results in
        //       less work overall and 10% better performance. It's more work on cache miss
        //       but cache miss is rare.
-        if let Some(nblocks) = self.tline.get_cached_rel_size(&rel, self.get_lsn()) {
+        if let Some(nblocks) = self
+            .tline
+            .get_cached_rel_size(&rel, Version::Modified(self))
+        {
            Ok(nblocks)
        } else if !self
            .tline
@@ -2667,7 +2710,7 @@ pub struct DatadirModificationStats {
 /// timeline to not miss the latest updates.
 #[derive(Clone, Copy)]
 pub enum Version<'a> {
-    Lsn(Lsn),
+    LsnRange(LsnRange),
    Modified(&'a DatadirModification<'a>),
 }

@@ -2679,7 +2722,7 @@ impl Version<'_> {
        ctx: &RequestContext,
    ) -> Result<Bytes, PageReconstructError> {
        match self {
-            Version::Lsn(lsn) => timeline.get(key, *lsn, ctx).await,
+            Version::LsnRange(lsns) => timeline.get(key, lsns.effective_lsn, ctx).await,
            Version::Modified(modification) => modification.get(key, ctx).await,
        }
    }
@@ -2701,12 +2744,26 @@ impl Version<'_> {
        }
    }

-    fn get_lsn(&self) -> Lsn {
+    pub fn is_latest(&self) -> bool {
        match self {
-            Version::Lsn(lsn) => *lsn,
+            Version::LsnRange(lsns) => lsns.is_latest(),
+            Version::Modified(_) => true,
+        }
+    }
+
+    pub fn get_lsn(&self) -> Lsn {
+        match self {
+            Version::LsnRange(lsns) => lsns.effective_lsn,
            Version::Modified(modification) => modification.lsn,
        }
    }
+
+    pub fn at(lsn: Lsn) -> Self {
+        Version::LsnRange(LsnRange {
+            effective_lsn: lsn,
+            request_lsn: lsn,
+        })
+    }
 }

 //--- Metadata structs stored in key-value pairs in the repository.
--- a/pageserver/src/task_mgr.rs
+++ b/pageserver/src/task_mgr.rs
@@ -276,9 +276,10 @@ pub enum TaskKind {
    // HTTP endpoint listener.
    HttpEndpointListener,

-    // Task that handles a single connection. A PageRequestHandler task
-    // starts detached from any particular tenant or timeline, but it can be
-    // associated with one later, after receiving a command from the client.
+    /// Task that handles a single page service connection. A PageRequestHandler
+    /// task starts detached from any particular tenant or timeline, but it can
+    /// be associated with one later, after receiving a command from the client.
+    /// Also used for the gRPC page service API, including the main server task.
    PageRequestHandler,

    /// Manages the WAL receiver connection for one timeline.
@@ -380,6 +381,10 @@ pub enum TaskKind {
    DetachAncestor,

    ImportPgdata,
+
+    /// Background task of [`crate::basebackup_cache::BasebackupCache`].
+    /// Prepares basebackups and clears outdated entries.
+    BasebackupCache,
 }

 #[derive(Default)]
--- a/pageserver/src/tenant.rs
+++ b/pageserver/src/tenant.rs
@@ -78,16 +78,18 @@ use self::timeline::uninit::{TimelineCreateGuard, TimelineExclusionError, Uninit
 use self::timeline::{
    EvictionTaskTenantState, GcCutoffs, TimelineDeleteProgress, TimelineResources, WaitLsnError,
 };
+use crate::basebackup_cache::BasebackupPrepareSender;
 use crate::config::PageServerConf;
 use crate::context;
 use crate::context::RequestContextBuilder;
 use crate::context::{DownloadBehavior, RequestContext};
 use crate::deletion_queue::{DeletionQueueClient, DeletionQueueError};
+use crate::feature_resolver::FeatureResolver;
 use crate::l0_flush::L0FlushGlobalState;
 use crate::metrics::{
    BROKEN_TENANTS_SET, CIRCUIT_BREAKERS_BROKEN, CIRCUIT_BREAKERS_UNBROKEN, CONCURRENT_INITDBS,
-    INITDB_RUN_TIME, INITDB_SEMAPHORE_ACQUISITION_TIME, TENANT, TENANT_STATE_METRIC,
-    TENANT_SYNTHETIC_SIZE_METRIC, remove_tenant_metrics,
+    INITDB_RUN_TIME, INITDB_SEMAPHORE_ACQUISITION_TIME, TENANT, TENANT_OFFLOADED_TIMELINES,
+    TENANT_STATE_METRIC, TENANT_SYNTHETIC_SIZE_METRIC, remove_tenant_metrics,
 };
 use crate::task_mgr::TaskKind;
 use crate::tenant::config::LocationMode;
@@ -157,6 +159,8 @@ pub struct TenantSharedResources {
    pub remote_storage: GenericRemoteStorage,
    pub deletion_queue_client: DeletionQueueClient,
    pub l0_flush_global_state: L0FlushGlobalState,
+    pub basebackup_prepare_sender: BasebackupPrepareSender,
+    pub feature_resolver: FeatureResolver,
 }

 /// A [`TenantShard`] is really an _attached_ tenant.  The configuration
@@ -296,7 +300,7 @@ pub struct TenantShard {
    ///   as in progress.
    /// * Imported timelines are removed when the storage controller calls the post timeline
    ///   import activation endpoint.
-    timelines_importing: std::sync::Mutex<HashMap<TimelineId, ImportingTimeline>>,
+    timelines_importing: std::sync::Mutex<HashMap<TimelineId, Arc<ImportingTimeline>>>,

    /// The last tenant manifest known to be in remote storage. None if the manifest has not yet
    /// been either downloaded or uploaded. Always Some after tenant attach.
@@ -317,12 +321,15 @@ pub struct TenantShard {
    gc_cs: tokio::sync::Mutex<()>,
    walredo_mgr: Option<Arc<WalRedoManager>>,

-    // provides access to timeline data sitting in the remote storage
+    /// Provides access to timeline data sitting in the remote storage.
    pub(crate) remote_storage: GenericRemoteStorage,

-    // Access to global deletion queue for when this tenant wants to schedule a deletion
+    /// Access to global deletion queue for when this tenant wants to schedule a deletion.
    deletion_queue_client: DeletionQueueClient,

+    /// A channel to send async requests to prepare a basebackup for the basebackup cache.
+    basebackup_prepare_sender: BasebackupPrepareSender,
+
    /// Cached logical sizes updated updated on each [`TenantShard::gather_size_inputs`].
    cached_logical_sizes: tokio::sync::Mutex<HashMap<(TimelineId, Lsn), u64>>,
    cached_synthetic_tenant_size: Arc<AtomicU64>,
@@ -375,6 +382,8 @@ pub struct TenantShard {
    pub(crate) gc_block: gc_block::GcBlock,

    l0_flush_global_state: L0FlushGlobalState,
+
+    pub(crate) feature_resolver: FeatureResolver,
 }
 impl std::fmt::Debug for TenantShard {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
@@ -663,6 +672,7 @@ pub enum MaybeOffloaded {
 pub enum TimelineOrOffloaded {
    Timeline(Arc<Timeline>),
    Offloaded(Arc<OffloadedTimeline>),
+    Importing(Arc<ImportingTimeline>),
 }

 impl TimelineOrOffloaded {
@@ -674,6 +684,9 @@ impl TimelineOrOffloaded {
            TimelineOrOffloaded::Offloaded(offloaded) => {
                TimelineOrOffloadedArcRef::Offloaded(offloaded)
            }
+            TimelineOrOffloaded::Importing(importing) => {
+                TimelineOrOffloadedArcRef::Importing(importing)
+            }
        }
    }
    pub fn tenant_shard_id(&self) -> TenantShardId {
@@ -686,12 +699,16 @@ impl TimelineOrOffloaded {
        match self {
            TimelineOrOffloaded::Timeline(timeline) => &timeline.delete_progress,
            TimelineOrOffloaded::Offloaded(offloaded) => &offloaded.delete_progress,
+            TimelineOrOffloaded::Importing(importing) => &importing.delete_progress,
        }
    }
    fn maybe_remote_client(&self) -> Option<Arc<RemoteTimelineClient>> {
        match self {
            TimelineOrOffloaded::Timeline(timeline) => Some(timeline.remote_client.clone()),
            TimelineOrOffloaded::Offloaded(_offloaded) => None,
+            TimelineOrOffloaded::Importing(importing) => {
+                Some(importing.timeline.remote_client.clone())
+            }
        }
    }
 }
@@ -699,6 +716,7 @@ impl TimelineOrOffloaded {
 pub enum TimelineOrOffloadedArcRef<'a> {
    Timeline(&'a Arc<Timeline>),
    Offloaded(&'a Arc<OffloadedTimeline>),
+    Importing(&'a Arc<ImportingTimeline>),
 }

 impl TimelineOrOffloadedArcRef<'_> {
@@ -706,12 +724,14 @@ impl TimelineOrOffloadedArcRef<'_> {
        match self {
            TimelineOrOffloadedArcRef::Timeline(timeline) => timeline.tenant_shard_id,
            TimelineOrOffloadedArcRef::Offloaded(offloaded) => offloaded.tenant_shard_id,
+            TimelineOrOffloadedArcRef::Importing(importing) => importing.timeline.tenant_shard_id,
        }
    }
    pub fn timeline_id(&self) -> TimelineId {
        match self {
            TimelineOrOffloadedArcRef::Timeline(timeline) => timeline.timeline_id,
            TimelineOrOffloadedArcRef::Offloaded(offloaded) => offloaded.timeline_id,
+            TimelineOrOffloadedArcRef::Importing(importing) => importing.timeline.timeline_id,
        }
    }
 }
@@ -728,6 +748,12 @@ impl<'a> From<&'a Arc<OffloadedTimeline>> for TimelineOrOffloadedArcRef<'a> {
    }
 }

+impl<'a> From<&'a Arc<ImportingTimeline>> for TimelineOrOffloadedArcRef<'a> {
+    fn from(timeline: &'a Arc<ImportingTimeline>) -> Self {
+        Self::Importing(timeline)
+    }
+}
+
 #[derive(Debug, thiserror::Error, PartialEq, Eq)]
 pub enum GetTimelineError {
    #[error("Timeline is shutting down")]
@@ -855,6 +881,14 @@ impl Debug for SetStoppingError {
    }
 }

+#[derive(thiserror::Error, Debug)]
+pub(crate) enum FinalizeTimelineImportError {
+    #[error("Import task not done yet")]
+    ImportTaskStillRunning,
+    #[error("Shutting down")]
+    ShuttingDown,
+}
+
 /// Arguments to [`TenantShard::create_timeline`].
 ///
 /// Not usable as an idempotency key for timeline creation because if [`CreateTimelineParamsBranch::ancestor_start_lsn`]
@@ -1141,10 +1175,20 @@ impl TenantShard {
            ctx,
        )?;
        let disk_consistent_lsn = timeline.get_disk_consistent_lsn();
-        anyhow::ensure!(
-            disk_consistent_lsn.is_valid(),
-            "Timeline {tenant_id}/{timeline_id} has invalid disk_consistent_lsn"
-        );
+
+        if !disk_consistent_lsn.is_valid() {
+            // As opposed to normal timelines which get initialised with a disk consitent LSN
+            // via initdb, imported timelines start from 0. If the import task stops before
+            // it advances disk consitent LSN, allow it to resume.
+            let in_progress_import = import_pgdata
+                .as_ref()
+                .map(|import| !import.is_done())
+                .unwrap_or(false);
+            if !in_progress_import {
+                anyhow::bail!("Timeline {tenant_id}/{timeline_id} has invalid disk_consistent_lsn");
+            }
+        }
+
        assert_eq!(
            disk_consistent_lsn,
            metadata.disk_consistent_lsn(),
@@ -1238,20 +1282,25 @@ impl TenantShard {
                    }
                }

-                // Sanity check: a timeline should have some content.
-                anyhow::ensure!(
-                    ancestor.is_some()
-                        || timeline
-                            .layers
-                            .read()
-                            .await
-                            .layer_map()
-                            .expect("currently loading, layer manager cannot be shutdown already")
-                            .iter_historic_layers()
-                            .next()
-                            .is_some(),
-                    "Timeline has no ancestor and no layer files"
-                );
+                if disk_consistent_lsn.is_valid() {
+                    // Sanity check: a timeline should have some content.
+                    // Exception: importing timelines might not yet have any
+                    anyhow::ensure!(
+                        ancestor.is_some()
+                            || timeline
+                                .layers
+                                .read()
+                                .await
+                                .layer_map()
+                                .expect(
+                                    "currently loading, layer manager cannot be shutdown already"
+                                )
+                                .iter_historic_layers()
+                                .next()
+                                .is_some(),
+                        "Timeline has no ancestor and no layer files"
+                    );
+                }

                Ok(TimelineInitAndSyncResult::ReadyToActivate)
            }
@@ -1286,6 +1335,8 @@ impl TenantShard {
            remote_storage,
            deletion_queue_client,
            l0_flush_global_state,
+            basebackup_prepare_sender,
+            feature_resolver,
        } = resources;

        let attach_mode = attached_conf.location.attach_mode;
@@ -1301,6 +1352,8 @@ impl TenantShard {
            remote_storage.clone(),
            deletion_queue_client,
            l0_flush_global_state,
+            basebackup_prepare_sender,
+            feature_resolver,
        ));

        // The attach task will carry a GateGuard, so that shutdown() reliably waits for it to drop out if
@@ -1753,20 +1806,25 @@ impl TenantShard {
                    },
                ) => {
                    let timeline_id = timeline.timeline_id;
+                    let import_task_gate = Gate::default();
+                    let import_task_guard = import_task_gate.enter().unwrap();
                    let import_task_handle =
                        tokio::task::spawn(self.clone().create_timeline_import_pgdata_task(
                            timeline.clone(),
                            import_pgdata,
                            guard,
+                            import_task_guard,
                            ctx.detached_child(TaskKind::ImportPgdata, DownloadBehavior::Warn),
                        ));

                    let prev = self.timelines_importing.lock().unwrap().insert(
                        timeline_id,
-                        ImportingTimeline {
+                        Arc::new(ImportingTimeline {
                            timeline: timeline.clone(),
                            import_task_handle,
-                        },
+                            import_task_gate,
+                            delete_progress: TimelineDeleteProgress::default(),
+                        }),
                    );

                    assert!(prev.is_none());
@@ -2384,6 +2442,17 @@ impl TenantShard {
            .collect()
    }

+    /// Lists timelines the tenant contains.
+    /// It's up to callers to omit certain timelines that are not considered ready for use.
+    pub fn list_importing_timelines(&self) -> Vec<Arc<ImportingTimeline>> {
+        self.timelines_importing
+            .lock()
+            .unwrap()
+            .values()
+            .map(Arc::clone)
+            .collect()
+    }
+
    /// Lists timelines the tenant manages, including offloaded ones.
    ///
    /// It's up to callers to omit certain timelines that are not considered ready for use.
@@ -2817,19 +2886,25 @@ impl TenantShard {

        let (timeline, timeline_create_guard) = uninit_timeline.finish_creation_myself();

+        let import_task_gate = Gate::default();
+        let import_task_guard = import_task_gate.enter().unwrap();
+
        let import_task_handle = tokio::spawn(self.clone().create_timeline_import_pgdata_task(
            timeline.clone(),
            index_part,
            timeline_create_guard,
+            import_task_guard,
            timeline_ctx.detached_child(TaskKind::ImportPgdata, DownloadBehavior::Warn),
        ));

        let prev = self.timelines_importing.lock().unwrap().insert(
            timeline.timeline_id,
-            ImportingTimeline {
+            Arc::new(ImportingTimeline {
                timeline: timeline.clone(),
                import_task_handle,
-            },
+                import_task_gate,
+                delete_progress: TimelineDeleteProgress::default(),
+            }),
        );

        // Idempotency is enforced higher up the stack
@@ -2847,13 +2922,13 @@ impl TenantShard {
    pub(crate) async fn finalize_importing_timeline(
        &self,
        timeline_id: TimelineId,
-    ) -> anyhow::Result<()> {
+    ) -> Result<(), FinalizeTimelineImportError> {
        let timeline = {
            let locked = self.timelines_importing.lock().unwrap();
            match locked.get(&timeline_id) {
                Some(importing_timeline) => {
                    if !importing_timeline.import_task_handle.is_finished() {
-                        return Err(anyhow::anyhow!("Import task not done yet"));
+                        return Err(FinalizeTimelineImportError::ImportTaskStillRunning);
                    }

                    importing_timeline.timeline.clone()
@@ -2866,8 +2941,13 @@ impl TenantShard {

        timeline
            .remote_client
-            .schedule_index_upload_for_import_pgdata_finalize()?;
-        timeline.remote_client.wait_completion().await?;
+            .schedule_index_upload_for_import_pgdata_finalize()
+            .map_err(|_err| FinalizeTimelineImportError::ShuttingDown)?;
+        timeline
+            .remote_client
+            .wait_completion()
+            .await
+            .map_err(|_err| FinalizeTimelineImportError::ShuttingDown)?;

        self.timelines_importing
            .lock()
@@ -2883,6 +2963,7 @@ impl TenantShard {
        timeline: Arc<Timeline>,
        index_part: import_pgdata::index_part_format::Root,
        timeline_create_guard: TimelineCreateGuard,
+        _import_task_guard: GateGuard,
        ctx: RequestContext,
    ) {
        debug_assert_current_span_has_tenant_and_timeline_id();
@@ -3128,11 +3209,18 @@ impl TenantShard {
                        .or_insert_with(|| Arc::new(GcCompactionQueue::new()))
                        .clone()
                };
+                let gc_compaction_strategy = self
+                    .feature_resolver
+                    .evaluate_multivariate("gc-comapction-strategy", self.tenant_shard_id.tenant_id)
+                    .ok();
+                let span = if let Some(gc_compaction_strategy) = gc_compaction_strategy {
+                    info_span!("gc_compact_timeline", timeline_id = %timeline.timeline_id, strategy = %gc_compaction_strategy)
+                } else {
+                    info_span!("gc_compact_timeline", timeline_id = %timeline.timeline_id)
+                };
                outcome = queue
                    .iteration(cancel, ctx, &self.gc_block, &timeline)
-                    .instrument(
-                        info_span!("gc_compact_timeline", timeline_id = %timeline.timeline_id),
-                    )
+                    .instrument(span)
                    .await?;
            }

@@ -3348,6 +3436,13 @@ impl TenantShard {
                activated_timelines += 1;
            }

+            let tid = self.tenant_shard_id.tenant_id.to_string();
+            let shard_id = self.tenant_shard_id.shard_slug().to_string();
+            let offloaded_timeline_count = timelines_offloaded_accessor.len();
+            TENANT_OFFLOADED_TIMELINES
+                .with_label_values(&[&tid, &shard_id])
+                .set(offloaded_timeline_count as u64);
+
            self.state.send_modify(move |current_state| {
                assert!(
                    matches!(current_state, TenantState::Activating(_)),
@@ -3457,8 +3552,9 @@ impl TenantShard {
            let mut timelines_importing = self.timelines_importing.lock().unwrap();
            timelines_importing
                .drain()
-                .for_each(|(_timeline_id, importing_timeline)| {
-                    importing_timeline.shutdown();
+                .for_each(|(timeline_id, importing_timeline)| {
+                    let span = tracing::info_span!("importing_timeline_shutdown", %timeline_id);
+                    js.spawn(async move { importing_timeline.shutdown().instrument(span).await });
                });
        }
        // test_long_timeline_create_then_tenant_delete is leaning on this message
@@ -3779,6 +3875,9 @@ impl TenantShard {
                        .build_timeline_client(offloaded.timeline_id, self.remote_storage.clone());
                    Arc::new(remote_client)
                }
+                TimelineOrOffloadedArcRef::Importing(_) => {
+                    unreachable!("Importing timelines are not included in the iterator")
+                }
            };

            // Shut down the timeline's remote client: this means that the indices we write
@@ -4232,6 +4331,8 @@ impl TenantShard {
        remote_storage: GenericRemoteStorage,
        deletion_queue_client: DeletionQueueClient,
        l0_flush_global_state: L0FlushGlobalState,
+        basebackup_prepare_sender: BasebackupPrepareSender,
+        feature_resolver: FeatureResolver,
    ) -> TenantShard {
        assert!(!attached_conf.location.generation.is_none());

@@ -4335,6 +4436,8 @@ impl TenantShard {
            ongoing_timeline_detach: std::sync::Mutex::default(),
            gc_block: Default::default(),
            l0_flush_global_state,
+            basebackup_prepare_sender,
+            feature_resolver,
        }
    }

@@ -4587,7 +4690,7 @@ impl TenantShard {

            target.cutoffs = GcCutoffs {
                space: space_cutoff,
-                time: Lsn::INVALID,
+                time: None,
            };
        }
    }
@@ -4671,7 +4774,7 @@ impl TenantShard {
                if let Some(ancestor_id) = timeline.get_ancestor_timeline_id() {
                    if let Some(ancestor_gc_cutoffs) = gc_cutoffs.get(&ancestor_id) {
                        target.within_ancestor_pitr =
-                            timeline.get_ancestor_lsn() >= ancestor_gc_cutoffs.time;
+                            Some(timeline.get_ancestor_lsn()) >= ancestor_gc_cutoffs.time;
                    }
                }

@@ -4684,13 +4787,15 @@ impl TenantShard {
                    } else {
                        0
                    });
-                timeline.metrics.pitr_history_size.set(
-                    timeline
-                        .get_last_record_lsn()
-                        .checked_sub(target.cutoffs.time)
-                        .unwrap_or(Lsn(0))
-                        .0,
-                );
+                if let Some(time_cutoff) = target.cutoffs.time {
+                    timeline.metrics.pitr_history_size.set(
+                        timeline
+                            .get_last_record_lsn()
+                            .checked_sub(time_cutoff)
+                            .unwrap_or_default()
+                            .0,
+                    );
+                }

                // Apply the cutoffs we found to the Timeline's GcInfo.  Why might we _not_ have cutoffs for a timeline?
                // - this timeline was created while we were finding cutoffs
@@ -4699,8 +4804,8 @@ impl TenantShard {
                    let original_cutoffs = target.cutoffs.clone();
                    // GC cutoffs should never go back
                    target.cutoffs = GcCutoffs {
-                        space: Lsn(cutoffs.space.0.max(original_cutoffs.space.0)),
-                        time: Lsn(cutoffs.time.0.max(original_cutoffs.time.0)),
+                        space: cutoffs.space.max(original_cutoffs.space),
+                        time: cutoffs.time.max(original_cutoffs.time),
                    }
                }
            }
@@ -4982,6 +5087,14 @@ impl TenantShard {
                info!("timeline already exists but is offloaded");
                Err(CreateTimelineError::Conflict)
            }
+            Err(TimelineExclusionError::AlreadyExists {
+                existing: TimelineOrOffloaded::Importing(_existing),
+                ..
+            }) => {
+                // If there's a timeline already importing, then we would hit
+                // the [`TimelineExclusionError::AlreadyCreating`] branch above.
+                unreachable!("Importing timelines hold the creation guard")
+            }
            Err(TimelineExclusionError::AlreadyExists {
                existing: TimelineOrOffloaded::Timeline(existing),
                arg,
@@ -5252,6 +5365,8 @@ impl TenantShard {
            pagestream_throttle_metrics: self.pagestream_throttle_metrics.clone(),
            l0_compaction_trigger: self.l0_compaction_trigger.clone(),
            l0_flush_global_state: self.l0_flush_global_state.clone(),
+            basebackup_prepare_sender: self.basebackup_prepare_sender.clone(),
+            feature_resolver: self.feature_resolver.clone(),
        }
    }

@@ -5560,6 +5675,14 @@ impl TenantShard {
            }
        }

+        // Update metrics
+        let tid = self.tenant_shard_id.to_string();
+        let shard_id = self.tenant_shard_id.shard_slug().to_string();
+        let set_key = &[tid.as_str(), shard_id.as_str()][..];
+        TENANT_OFFLOADED_TIMELINES
+            .with_label_values(set_key)
+            .set(manifest.offloaded_timelines.len() as u64);
+
        // Upload the manifest. Remote storage does no retries internally, so retry here.
        match backoff::retry(
            || async {
@@ -5709,6 +5832,7 @@ pub(crate) mod harness {
        pub conf: &'static PageServerConf,
        pub tenant_conf: pageserver_api::models::TenantConfig,
        pub tenant_shard_id: TenantShardId,
+        pub shard_identity: ShardIdentity,
        pub generation: Generation,
        pub shard: ShardIndex,
        pub remote_storage: GenericRemoteStorage,
@@ -5776,6 +5900,7 @@ pub(crate) mod harness {
                conf,
                tenant_conf,
                tenant_shard_id,
+                shard_identity,
                generation,
                shard,
                remote_storage,
@@ -5826,6 +5951,8 @@ pub(crate) mod harness {
        ) -> anyhow::Result<Arc<TenantShard>> {
            let walredo_mgr = Arc::new(WalRedoManager::from(TestRedoManager));

+            let (basebackup_requst_sender, _) = tokio::sync::mpsc::unbounded_channel();
+
            let tenant = Arc::new(TenantShard::new(
                TenantState::Attaching,
                self.conf,
@@ -5835,14 +5962,15 @@ pub(crate) mod harness {
                    &ShardParameters::default(),
                ))
                .unwrap(),
-                // This is a legacy/test code path: sharding isn't supported here.
-                ShardIdentity::unsharded(),
+                self.shard_identity,
                Some(walredo_mgr),
                self.tenant_shard_id,
                self.remote_storage.clone(),
                self.deletion_queue.new_client(),
                // TODO: ideally we should run all unit tests with both configs
                L0FlushGlobalState::new(L0FlushConfig::default()),
+                basebackup_requst_sender,
+                FeatureResolver::new_disabled(),
            ));

            let preload = tenant
@@ -5956,6 +6084,7 @@ mod tests {
    use timeline::compaction::{KeyHistoryRetention, KeyLogAtLsn};
    use timeline::{CompactOptions, DeltaLayerTestDesc, VersionedKeySpaceQuery};
    use utils::id::TenantId;
+    use utils::shard::{ShardCount, ShardNumber};

    use super::*;
    use crate::DEFAULT_PG_VERSION;
@@ -8284,10 +8413,24 @@ mod tests {
            }

            tline.freeze_and_flush().await?;
+            // Force layers to L1
+            tline
+                .compact(
+                    &cancel,
+                    {
+                        let mut flags = EnumSet::new();
+                        flags.insert(CompactFlags::ForceL0Compaction);
+                        flags
+                    },
+                    &ctx,
+                )
+                .await?;

            if iter % 5 == 0 {
+                let scan_lsn = Lsn(lsn.0 + 1);
+                info!("scanning at {}", scan_lsn);
                let (_, before_delta_file_accessed) =
-                    scan_with_statistics(&tline, &keyspace, lsn, &ctx, io_concurrency.clone())
+                    scan_with_statistics(&tline, &keyspace, scan_lsn, &ctx, io_concurrency.clone())
                        .await?;
                tline
                    .compact(
@@ -8296,13 +8439,14 @@ mod tests {
                            let mut flags = EnumSet::new();
                            flags.insert(CompactFlags::ForceImageLayerCreation);
                            flags.insert(CompactFlags::ForceRepartition);
+                            flags.insert(CompactFlags::ForceL0Compaction);
                            flags
                        },
                        &ctx,
                    )
                    .await?;
                let (_, after_delta_file_accessed) =
-                    scan_with_statistics(&tline, &keyspace, lsn, &ctx, io_concurrency.clone())
+                    scan_with_statistics(&tline, &keyspace, scan_lsn, &ctx, io_concurrency.clone())
                        .await?;
                assert!(
                    after_delta_file_accessed < before_delta_file_accessed,
@@ -8596,8 +8740,10 @@ mod tests {
        lsn: Lsn,
        ctx: &RequestContext,
    ) -> Result<Option<Bytes>, GetVectoredError> {
-        let io_concurrency =
-            IoConcurrency::spawn_from_conf(tline.conf, tline.gate.enter().unwrap());
+        let io_concurrency = IoConcurrency::spawn_from_conf(
+            tline.conf.get_vectored_concurrent_io,
+            tline.gate.enter().unwrap(),
+        );
        let mut reconstruct_state = ValuesReconstructState::new(io_concurrency);
        let query = VersionedKeySpaceQuery::uniform(KeySpace::single(key..key.next()), lsn);
        let mut res = tline
@@ -8741,6 +8887,8 @@ mod tests {

        let cancel = CancellationToken::new();

+        // Image layer creation happens on the disk_consistent_lsn so we need to force set it now.
+        tline.force_set_disk_consistent_lsn(Lsn(0x40));
        tline
            .compact(
                &cancel,
@@ -8754,8 +8902,7 @@ mod tests {
            )
            .await
            .unwrap();
-
-        // Image layers are created at last_record_lsn
+        // Image layers are created at repartition LSN
        let images = tline
            .inspect_image_layers(Lsn(0x40), &ctx, io_concurrency.clone())
            .await
@@ -8935,7 +9082,7 @@ mod tests {
                .await;
            // Update GC info
            let mut guard = tline.gc_info.write().unwrap();
-            guard.cutoffs.time = Lsn(0x30);
+            guard.cutoffs.time = Some(Lsn(0x30));
            guard.cutoffs.space = Lsn(0x30);
        }

@@ -9043,7 +9190,7 @@ mod tests {
                .await;
            // Update GC info
            let mut guard = tline.gc_info.write().unwrap();
-            guard.cutoffs.time = Lsn(0x40);
+            guard.cutoffs.time = Some(Lsn(0x40));
            guard.cutoffs.space = Lsn(0x40);
        }
        tline
@@ -9273,6 +9420,77 @@ mod tests {
        Ok(())
    }

+    #[tokio::test]
+    async fn test_failed_flush_should_not_update_disk_consistent_lsn() -> anyhow::Result<()> {
+        //
+        // Setup
+        //
+        let harness = TenantHarness::create_custom(
+            "test_failed_flush_should_not_upload_disk_consistent_lsn",
+            pageserver_api::models::TenantConfig::default(),
+            TenantId::generate(),
+            ShardIdentity::new(ShardNumber(0), ShardCount(4), ShardStripeSize(128)).unwrap(),
+            Generation::new(1),
+        )
+        .await?;
+        let (tenant, ctx) = harness.load().await;
+
+        let timeline = tenant
+            .create_test_timeline(TIMELINE_ID, Lsn(0x10), DEFAULT_PG_VERSION, &ctx)
+            .await?;
+        assert_eq!(timeline.get_shard_identity().count, ShardCount(4));
+        let mut writer = timeline.writer().await;
+        writer
+            .put(
+                *TEST_KEY,
+                Lsn(0x20),
+                &Value::Image(test_img("foo at 0x20")),
+                &ctx,
+            )
+            .await?;
+        writer.finish_write(Lsn(0x20));
+        drop(writer);
+        timeline.freeze_and_flush().await.unwrap();
+
+        timeline.remote_client.wait_completion().await.unwrap();
+        let disk_consistent_lsn = timeline.get_disk_consistent_lsn();
+        let remote_consistent_lsn = timeline.get_remote_consistent_lsn_projected();
+        assert_eq!(Some(disk_consistent_lsn), remote_consistent_lsn);
+
+        //
+        // Test
+        //
+
+        let mut writer = timeline.writer().await;
+        writer
+            .put(
+                *TEST_KEY,
+                Lsn(0x30),
+                &Value::Image(test_img("foo at 0x30")),
+                &ctx,
+            )
+            .await?;
+        writer.finish_write(Lsn(0x30));
+        drop(writer);
+
+        fail::cfg(
+            "flush-layer-before-update-remote-consistent-lsn",
+            "return()",
+        )
+        .unwrap();
+
+        let flush_res = timeline.freeze_and_flush().await;
+        // if flush failed, the disk/remote consistent LSN should not be updated
+        assert!(flush_res.is_err());
+        assert_eq!(disk_consistent_lsn, timeline.get_disk_consistent_lsn());
+        assert_eq!(
+            remote_consistent_lsn,
+            timeline.get_remote_consistent_lsn_projected()
+        );
+
+        Ok(())
+    }
+
    #[cfg(feature = "testing")]
    #[tokio::test]
    async fn test_simple_bottom_most_compaction_deltas_1() -> anyhow::Result<()> {
@@ -9461,7 +9679,7 @@ mod tests {
            *guard = GcInfo {
                retain_lsns: vec![],
                cutoffs: GcCutoffs {
-                    time: Lsn(0x30),
+                    time: Some(Lsn(0x30)),
                    space: Lsn(0x30),
                },
                leases: Default::default(),
@@ -9545,7 +9763,7 @@ mod tests {
                .await;
            // Update GC info
            let mut guard = tline.gc_info.write().unwrap();
-            guard.cutoffs.time = Lsn(0x40);
+            guard.cutoffs.time = Some(Lsn(0x40));
            guard.cutoffs.space = Lsn(0x40);
        }
        tline
@@ -10016,7 +10234,7 @@ mod tests {
                    (Lsn(0x20), tline.timeline_id, MaybeOffloaded::No),
                ],
                cutoffs: GcCutoffs {
-                    time: Lsn(0x30),
+                    time: Some(Lsn(0x30)),
                    space: Lsn(0x30),
                },
                leases: Default::default(),
@@ -10079,7 +10297,7 @@ mod tests {
        let verify_result = || async {
            let gc_horizon = {
                let gc_info = tline.gc_info.read().unwrap();
-                gc_info.cutoffs.time
+                gc_info.cutoffs.time.unwrap_or_default()
            };
            for idx in 0..10 {
                assert_eq!(
@@ -10157,7 +10375,7 @@ mod tests {
                .await;
            // Update GC info
            let mut guard = tline.gc_info.write().unwrap();
-            guard.cutoffs.time = Lsn(0x38);
+            guard.cutoffs.time = Some(Lsn(0x38));
            guard.cutoffs.space = Lsn(0x38);
        }
        tline
@@ -10265,7 +10483,7 @@ mod tests {
                    (Lsn(0x20), tline.timeline_id, MaybeOffloaded::No),
                ],
                cutoffs: GcCutoffs {
-                    time: Lsn(0x30),
+                    time: Some(Lsn(0x30)),
                    space: Lsn(0x30),
                },
                leases: Default::default(),
@@ -10328,7 +10546,7 @@ mod tests {
        let verify_result = || async {
            let gc_horizon = {
                let gc_info = tline.gc_info.read().unwrap();
-                gc_info.cutoffs.time
+                gc_info.cutoffs.time.unwrap_or_default()
            };
            for idx in 0..10 {
                assert_eq!(
@@ -10514,7 +10732,7 @@ mod tests {
            *guard = GcInfo {
                retain_lsns: vec![(Lsn(0x18), branch_tline.timeline_id, MaybeOffloaded::No)],
                cutoffs: GcCutoffs {
-                    time: Lsn(0x10),
+                    time: Some(Lsn(0x10)),
                    space: Lsn(0x10),
                },
                leases: Default::default(),
@@ -10534,7 +10752,7 @@ mod tests {
            *guard = GcInfo {
                retain_lsns: vec![(Lsn(0x40), branch_tline.timeline_id, MaybeOffloaded::No)],
                cutoffs: GcCutoffs {
-                    time: Lsn(0x50),
+                    time: Some(Lsn(0x50)),
                    space: Lsn(0x50),
                },
                leases: Default::default(),
@@ -11255,7 +11473,7 @@ mod tests {
            *guard = GcInfo {
                retain_lsns: vec![(Lsn(0x20), tline.timeline_id, MaybeOffloaded::No)],
                cutoffs: GcCutoffs {
-                    time: Lsn(0x30),
+                    time: Some(Lsn(0x30)),
                    space: Lsn(0x30),
                },
                leases: Default::default(),
@@ -11644,7 +11862,7 @@ mod tests {
                    (Lsn(0x20), tline.timeline_id, MaybeOffloaded::No),
                ],
                cutoffs: GcCutoffs {
-                    time: Lsn(0x30),
+                    time: Some(Lsn(0x30)),
                    space: Lsn(0x30),
                },
                leases: Default::default(),
@@ -11707,7 +11925,7 @@ mod tests {
        let verify_result = || async {
            let gc_horizon = {
                let gc_info = tline.gc_info.read().unwrap();
-                gc_info.cutoffs.time
+                gc_info.cutoffs.time.unwrap_or_default()
            };
            for idx in 0..10 {
                assert_eq!(
@@ -11896,7 +12114,7 @@ mod tests {
                    (Lsn(0x20), tline.timeline_id, MaybeOffloaded::No),
                ],
                cutoffs: GcCutoffs {
-                    time: Lsn(0x30),
+                    time: Some(Lsn(0x30)),
                    space: Lsn(0x30),
                },
                leases: Default::default(),
@@ -11959,7 +12177,7 @@ mod tests {
        let verify_result = || async {
            let gc_horizon = {
                let gc_info = tline.gc_info.read().unwrap();
-                gc_info.cutoffs.time
+                gc_info.cutoffs.time.unwrap_or_default()
            };
            for idx in 0..10 {
                assert_eq!(
@@ -12222,7 +12440,7 @@ mod tests {
            *guard = GcInfo {
                retain_lsns: vec![],
                cutoffs: GcCutoffs {
-                    time: Lsn(0x30),
+                    time: Some(Lsn(0x30)),
                    space: Lsn(0x30),
                },
                leases: Default::default(),
--- a/pageserver/src/tenant/remote_timeline_client.rs
+++ b/pageserver/src/tenant/remote_timeline_client.rs
@@ -1348,6 +1348,21 @@ impl RemoteTimelineClient {
        Ok(())
    }

+    pub(crate) fn schedule_unlinking_of_layers_from_index_part<I>(
+        self: &Arc<Self>,
+        names: I,
+    ) -> Result<(), NotInitialized>
+    where
+        I: IntoIterator<Item = LayerName>,
+    {
+        let mut guard = self.upload_queue.lock().unwrap();
+        let upload_queue = guard.initialized_mut()?;
+
+        self.schedule_unlinking_of_layers_from_index_part0(upload_queue, names);
+
+        Ok(())
+    }
+
    /// Update the remote index file, removing the to-be-deleted files from the index,
    /// allowing scheduling of actual deletions later.
    fn schedule_unlinking_of_layers_from_index_part0<I>(
--- a/pageserver/src/tenant/size.rs
+++ b/pageserver/src/tenant/size.rs
@@ -235,7 +235,7 @@ pub(super) async fn gather_inputs(
        // than our internal space cutoff.  This means that if someone drops a database and waits for their
        // PITR interval, they will see synthetic size decrease, even if we are still storing data inside
        // the space cutoff.
-        let mut next_pitr_cutoff = gc_info.cutoffs.time;
+        let mut next_pitr_cutoff = gc_info.cutoffs.time.unwrap_or_default(); // TODO: handle None

        // If the caller provided a shorter retention period, use that instead of the GC cutoff.
        let retention_param_cutoff = if let Some(max_retention_period) = max_retention_period {
--- a/pageserver/src/tenant/storage_layer.rs
+++ b/pageserver/src/tenant/storage_layer.rs
@@ -31,6 +31,7 @@ pub use inmemory_layer::InMemoryLayer;
 pub(crate) use layer::{EvictionError, Layer, ResidentLayer};
 pub use layer_desc::{PersistentLayerDesc, PersistentLayerKey};
 pub use layer_name::{DeltaLayerName, ImageLayerName, LayerName};
+use pageserver_api::config::GetVectoredConcurrentIo;
 use pageserver_api::key::Key;
 use pageserver_api::keyspace::{KeySpace, KeySpaceRandomAccum};
 use pageserver_api::record::NeonWalRecord;
@@ -43,7 +44,6 @@ use self::inmemory_layer::InMemoryLayerFileId;
 use super::PageReconstructError;
 use super::layer_map::InMemoryLayerDesc;
 use super::timeline::{GetVectoredError, ReadPath};
-use crate::config::PageServerConf;
 use crate::context::{
    AccessStatsBehavior, PerfInstrumentFutureExt, RequestContext, RequestContextBuilder,
 };
@@ -318,11 +318,10 @@ impl IoConcurrency {
    }

    pub(crate) fn spawn_from_conf(
-        conf: &'static PageServerConf,
+        conf: GetVectoredConcurrentIo,
        gate_guard: GateGuard,
    ) -> IoConcurrency {
-        use pageserver_api::config::GetVectoredConcurrentIo;
-        let selected = match conf.get_vectored_concurrent_io {
+        let selected = match conf {
            GetVectoredConcurrentIo::Sequential => SelectedIoConcurrency::Sequential,
            GetVectoredConcurrentIo::SidecarTask => SelectedIoConcurrency::SidecarTask(gate_guard),
        };
--- a/pageserver/src/tenant/storage_layer/inmemory_layer.rs
+++ b/pageserver/src/tenant/storage_layer/inmemory_layer.rs
@@ -63,7 +63,28 @@ pub struct InMemoryLayer {

    opened_at: Instant,

-    /// The above fields never change, except for `end_lsn`, which is only set once.
+    /// All versions of all pages in the layer are kept here. Indexed
+    /// by block number and LSN. The [`IndexEntry`] is an offset into the
+    /// ephemeral file where the page version is stored.
+    ///
+    /// We use a separate lock for the index to reduce the critical section
+    /// during which reads cannot be planned.
+    ///
+    /// If you need access to both the index and the underlying file at the same time,
+    /// respect the following locking order to avoid deadlocks:
+    /// 1. [`InMemoryLayer::inner`]
+    /// 2. [`InMemoryLayer::index`]
+    ///
+    /// Note that the file backing [`InMemoryLayer::inner`] is append-only,
+    /// so it is not necessary to hold simultaneous locks on index.
+    /// This avoids holding index locks across IO, and is crucial for avoiding read tail latency.
+    /// In particular:
+    /// 1. It is safe to read and release [`InMemoryLayer::index`] before locking and reading from [`InMemoryLayer::inner`].
+    /// 2. It is safe to write and release [`InMemoryLayer::inner`] before locking and updating [`InMemoryLayer::index`].
+    index: RwLock<BTreeMap<CompactKey, VecMap<Lsn, IndexEntry>>>,
+
+    /// The above fields never change, except for `end_lsn`, which is only set once,
+    /// and `index` (see rationale there).
    /// All other changing parts are in `inner`, and protected by a mutex.
    inner: RwLock<InMemoryLayerInner>,

@@ -81,11 +102,6 @@ impl std::fmt::Debug for InMemoryLayer {
 }

 pub struct InMemoryLayerInner {
-    /// All versions of all pages in the layer are kept here. Indexed
-    /// by block number and LSN. The [`IndexEntry`] is an offset into the
-    /// ephemeral file where the page version is stored.
-    index: BTreeMap<CompactKey, VecMap<Lsn, IndexEntry>>,
-
    /// The values are stored in a serialized format in this file.
    /// Each serialized Value is preceded by a 'u32' length field.
    /// PerSeg::page_versions map stores offsets into this file.
@@ -105,7 +121,7 @@ const MAX_SUPPORTED_BLOB_LEN_BITS: usize = {
    trailing_ones
 };

-/// See [`InMemoryLayerInner::index`].
+/// See [`InMemoryLayer::index`].
 ///
 /// For memory efficiency, the data is packed into a u64.
 ///
@@ -425,7 +441,7 @@ impl InMemoryLayer {
            .page_content_kind(PageContentKind::InMemoryLayer)
            .attached_child();

-        let inner = self.inner.read().await;
+        let index = self.index.read().await;

        struct ValueRead {
            entry_lsn: Lsn,
@@ -435,10 +451,7 @@ impl InMemoryLayer {
        let mut ios: HashMap<(Key, Lsn), OnDiskValueIo> = Default::default();

        for range in keyspace.ranges.iter() {
-            for (key, vec_map) in inner
-                .index
-                .range(range.start.to_compact()..range.end.to_compact())
-            {
+            for (key, vec_map) in index.range(range.start.to_compact()..range.end.to_compact()) {
                let key = Key::from_compact(*key);
                let slice = vec_map.slice_range(lsn_range.clone());

@@ -466,7 +479,7 @@ impl InMemoryLayer {
                }
            }
        }
-        drop(inner); // release the lock before we spawn the IO; if it's serial-mode IO we will deadlock on the read().await below
+        drop(index); // release the lock before we spawn the IO; if it's serial-mode IO we will deadlock on the read().await below
        let read_from = Arc::clone(self);
        let read_ctx = ctx.attached_child();
        reconstruct_state
@@ -573,8 +586,8 @@ impl InMemoryLayer {
            start_lsn,
            end_lsn: OnceLock::new(),
            opened_at: Instant::now(),
+            index: RwLock::new(BTreeMap::new()),
            inner: RwLock::new(InMemoryLayerInner {
-                index: BTreeMap::new(),
                file,
                resource_units: GlobalResourceUnits::new(),
            }),
@@ -592,31 +605,39 @@ impl InMemoryLayer {
        serialized_batch: SerializedValueBatch,
        ctx: &RequestContext,
    ) -> anyhow::Result<()> {
-        let mut inner = self.inner.write().await;
-        self.assert_writable();
+        let (base_offset, metadata) = {
+            let mut inner = self.inner.write().await;
+            self.assert_writable();

-        let base_offset = inner.file.len();
+            let base_offset = inner.file.len();

-        let SerializedValueBatch {
-            raw,
-            metadata,
-            max_lsn: _,
-            len: _,
-        } = serialized_batch;
+            let SerializedValueBatch {
+                raw,
+                metadata,
+                max_lsn: _,
+                len: _,
+            } = serialized_batch;

-        // Write the batch to the file
-        inner.file.write_raw(&raw, ctx).await?;
-        let new_size = inner.file.len();
+            // Write the batch to the file
+            inner.file.write_raw(&raw, ctx).await?;
+            let new_size = inner.file.len();

-        let expected_new_len = base_offset
-            .checked_add(raw.len().into_u64())
-            // write_raw would error if we were to overflow u64.
-            // also IndexEntry and higher levels in
-            //the code don't allow the file to grow that large
-            .unwrap();
-        assert_eq!(new_size, expected_new_len);
+            let expected_new_len = base_offset
+                .checked_add(raw.len().into_u64())
+                // write_raw would error if we were to overflow u64.
+                // also IndexEntry and higher levels in
+                //the code don't allow the file to grow that large
+                .unwrap();
+            assert_eq!(new_size, expected_new_len);
+
+            inner.resource_units.maybe_publish_size(new_size);
+
+            (base_offset, metadata)
+        };

        // Update the index with the new entries
+        let mut index = self.index.write().await;
+
        for meta in metadata {
            let SerializedValueMeta {
                key,
@@ -639,7 +660,7 @@ impl InMemoryLayer {
                will_init,
            })?;

-            let vec_map = inner.index.entry(key).or_default();
+            let vec_map = index.entry(key).or_default();
            let old = vec_map.append_or_update_last(lsn, index_entry).unwrap().0;
            if old.is_some() {
                // This should not break anything, but is unexpected: ingestion code aims to filter out
@@ -658,8 +679,6 @@ impl InMemoryLayer {
            );
        }

-        inner.resource_units.maybe_publish_size(new_size);
-
        Ok(())
    }

@@ -680,6 +699,18 @@ impl InMemoryLayer {

    /// Records the end_lsn for non-dropped layers.
    /// `end_lsn` is exclusive
+    ///
+    /// A note on locking:
+    /// The current API of [`InMemoryLayer`] does not ensure that there's no ongoing
+    /// writes while freezing the layer. This is enforced at a higher level via
+    /// [`crate::tenant::Timeline::write_lock`]. Freeze might be called via two code paths:
+    /// 1. Via the active [`crate::tenant::timeline::TimelineWriter`]. This holds the
+    ///    Timeline::write_lock for its lifetime. The rolling is handled in
+    ///    [`crate::tenant::timeline::TimelineWriter::put_batch`]. It's a &mut self function
+    ///    so can't be called from different threads.
+    /// 2. In the background via [`crate::tenant::Timeline::maybe_freeze_ephemeral_layer`].
+    ///    This only proceeds if try_lock on Timeline::write_lock succeeds (i.e. there's no active writer),
+    ///    hence there can be no concurrent writes
    pub async fn freeze(&self, end_lsn: Lsn) {
        assert!(
            self.start_lsn < end_lsn,
@@ -700,8 +731,8 @@ impl InMemoryLayer {

        #[cfg(debug_assertions)]
        {
-            let inner = self.inner.write().await;
-            for vec_map in inner.index.values() {
+            let index = self.index.read().await;
+            for vec_map in index.values() {
                for (lsn, _) in vec_map.as_slice() {
                    assert!(*lsn < end_lsn);
                }
@@ -724,14 +755,11 @@ impl InMemoryLayer {
    ) -> Result<Option<(PersistentLayerDesc, Utf8PathBuf)>> {
        // Grab the lock in read-mode. We hold it over the I/O, but because this
        // layer is not writeable anymore, no one should be trying to acquire the
-        // write lock on it, so we shouldn't block anyone. There's one exception
-        // though: another thread might have grabbed a reference to this layer
-        // in `get_layer_for_write' just before the checkpointer called
-        // `freeze`, and then `write_to_disk` on it. When the thread gets the
-        // lock, it will see that it's not writeable anymore and retry, but it
-        // would have to wait until we release it. That race condition is very
-        // rare though, so we just accept the potential latency hit for now.
+        // write lock on it, so we shouldn't block anyone. See the comment on
+        // [`InMemoryLayer::freeze`] to understand how locking between the append path
+        // and layer flushing works.
        let inner = self.inner.read().await;
+        let index = self.index.read().await;

        use l0_flush::Inner;
        let _concurrency_permit = match l0_flush_global_state {
@@ -743,13 +771,9 @@ impl InMemoryLayer {
        let key_count = if let Some(key_range) = key_range {
            let key_range = key_range.start.to_compact()..key_range.end.to_compact();

-            inner
-                .index
-                .iter()
-                .filter(|(k, _)| key_range.contains(k))
-                .count()
+            index.iter().filter(|(k, _)| key_range.contains(k)).count()
        } else {
-            inner.index.len()
+            index.len()
        };
        if key_count == 0 {
            return Ok(None);
@@ -772,7 +796,7 @@ impl InMemoryLayer {
                let file_contents = inner.file.load_to_io_buf(ctx).await?;
                let file_contents = file_contents.freeze();

-                for (key, vec_map) in inner.index.iter() {
+                for (key, vec_map) in index.iter() {
                    // Write all page versions
                    for (lsn, entry) in vec_map
                        .as_slice()
--- a/pageserver/src/tenant/timeline.rs
+++ b/pageserver/src/tenant/timeline.rs
@@ -14,6 +14,7 @@ pub mod span;
 pub mod uninit;
 mod walreceiver;

+use hashlink::LruCache;
 use std::array;
 use std::cmp::{max, min};
 use std::collections::btree_map::Entry;
@@ -23,8 +24,6 @@ use std::sync::atomic::{AtomicBool, AtomicU64, Ordering as AtomicOrdering};
 use std::sync::{Arc, Mutex, OnceLock, RwLock, Weak};
 use std::time::{Duration, Instant, SystemTime};

-use crate::PERF_TRACE_TARGET;
-use crate::walredo::RedoAttemptType;
 use anyhow::{Context, Result, anyhow, bail, ensure};
 use arc_swap::{ArcSwap, ArcSwapOption};
 use bytes::Bytes;
@@ -93,15 +92,18 @@ use super::storage_layer::{LayerFringe, LayerVisibilityHint, ReadableLayer};
 use super::tasks::log_compaction_error;
 use super::upload_queue::NotInitialized;
 use super::{
-    AttachedTenantConf, GcError, HeatMapTimeline, MaybeOffloaded,
+    AttachedTenantConf, BasebackupPrepareSender, GcError, HeatMapTimeline, MaybeOffloaded,
    debug_assert_current_span_has_tenant_and_timeline_id,
 };
+use crate::PERF_TRACE_TARGET;
 use crate::aux_file::AuxFileSizeEstimator;
+use crate::basebackup_cache::BasebackupPrepareRequest;
 use crate::config::PageServerConf;
 use crate::context::{
    DownloadBehavior, PerfInstrumentFutureExt, RequestContext, RequestContextBuilder,
 };
 use crate::disk_usage_eviction_task::{DiskUsageEvictionInfo, EvictionCandidate, finite_f32};
+use crate::feature_resolver::FeatureResolver;
 use crate::keyspace::{KeyPartitioning, KeySpace};
 use crate::l0_flush::{self, L0FlushGlobalState};
 use crate::metrics::{
@@ -130,6 +132,7 @@ use crate::tenant::tasks::BackgroundLoopKind;
 use crate::tenant::timeline::logical_size::CurrentLogicalSize;
 use crate::virtual_file::{MaybeFatalIo, VirtualFile};
 use crate::walingest::WalLagCooldown;
+use crate::walredo::RedoAttemptType;
 use crate::{ZERO_PAGE, task_mgr, walredo};

 #[derive(Debug, PartialEq, Eq, Clone, Copy)]
@@ -195,16 +198,8 @@ pub struct TimelineResources {
    pub pagestream_throttle_metrics: Arc<crate::metrics::tenant_throttling::Pagestream>,
    pub l0_compaction_trigger: Arc<Notify>,
    pub l0_flush_global_state: l0_flush::L0FlushGlobalState,
-}
-
-/// The relation size cache caches relation sizes at the end of the timeline. It speeds up WAL
-/// ingestion considerably, because WAL ingestion needs to check on most records if the record
-/// implicitly extends the relation.  At startup, `complete_as_of` is initialized to the current end
-/// of the timeline (disk_consistent_lsn).  It's used on reads of relation sizes to check if the
-/// value can be used to also update the cache, see [`Timeline::update_cached_rel_size`].
-pub(crate) struct RelSizeCache {
-    pub(crate) complete_as_of: Lsn,
-    pub(crate) map: HashMap<RelTag, (Lsn, BlockNumber)>,
+    pub basebackup_prepare_sender: BasebackupPrepareSender,
+    pub feature_resolver: FeatureResolver,
 }

 pub struct Timeline {
@@ -365,7 +360,8 @@ pub struct Timeline {
    pub walreceiver: Mutex<Option<WalReceiver>>,

    /// Relation size cache
-    pub(crate) rel_size_cache: RwLock<RelSizeCache>,
+    pub(crate) rel_size_latest_cache: RwLock<HashMap<RelTag, (Lsn, BlockNumber)>>,
+    pub(crate) rel_size_snapshot_cache: Mutex<LruCache<(Lsn, RelTag), BlockNumber>>,

    download_all_remote_layers_task_info: RwLock<Option<DownloadRemoteLayersTaskInfo>>,

@@ -447,6 +443,11 @@ pub struct Timeline {
    pub(crate) rel_size_v2_status: ArcSwapOption<RelSizeMigration>,

    wait_lsn_log_slow: tokio::sync::Semaphore,
+
+    /// A channel to send async requests to prepare a basebackup for the basebackup cache.
+    basebackup_prepare_sender: BasebackupPrepareSender,
+
+    feature_resolver: FeatureResolver,
 }

 pub(crate) enum PreviousHeatmap {
@@ -537,29 +538,24 @@ impl GcInfo {
 /// The `GcInfo` component describing which Lsns need to be retained.  Functionally, this
 /// is a single number (the oldest LSN which we must retain), but it internally distinguishes
 /// between time-based and space-based retention for observability and consumption metrics purposes.
-#[derive(Debug, Clone)]
+#[derive(Clone, Debug, Default)]
 pub(crate) struct GcCutoffs {
    /// Calculated from the [`pageserver_api::models::TenantConfig::gc_horizon`], this LSN indicates how much
    /// history we must keep to retain a specified number of bytes of WAL.
    pub(crate) space: Lsn,

-    /// Calculated from [`pageserver_api::models::TenantConfig::pitr_interval`], this LSN indicates how much
-    /// history we must keep to enable reading back at least the PITR interval duration.
-    pub(crate) time: Lsn,
-}
-
-impl Default for GcCutoffs {
-    fn default() -> Self {
-        Self {
-            space: Lsn::INVALID,
-            time: Lsn::INVALID,
-        }
-    }
+    /// Calculated from [`pageserver_api::models::TenantConfig::pitr_interval`], this LSN indicates
+    /// how much history we must keep to enable reading back at least the PITR interval duration.
+    ///
+    /// None indicates that the PITR cutoff has not been computed. A PITR interval of 0 will yield
+    /// Some(last_record_lsn).
+    pub(crate) time: Option<Lsn>,
 }

 impl GcCutoffs {
    fn select_min(&self) -> Lsn {
-        std::cmp::min(self.space, self.time)
+        // NB: if we haven't computed the PITR cutoff yet, we can't GC anything.
+        self.space.min(self.time.unwrap_or_default())
    }
 }

@@ -1041,6 +1037,7 @@ pub(crate) enum WaitLsnWaiter<'a> {
    Tenant,
    PageService,
    HttpEndpoint,
+    BaseBackupCache,
 }

 /// Argument to [`Timeline::shutdown`].
@@ -1096,11 +1093,14 @@ impl Timeline {
    /// Get the bytes written since the PITR cutoff on this branch, and
    /// whether this branch's ancestor_lsn is within its parent's PITR.
    pub(crate) fn get_pitr_history_stats(&self) -> (u64, bool) {
+        // TODO: for backwards compatibility, we return the full history back to 0 when the PITR
+        // cutoff has not yet been initialized. This should return None instead, but this is exposed
+        // in external HTTP APIs and callers may not handle a null value.
        let gc_info = self.gc_info.read().unwrap();
        let history = self
            .get_last_record_lsn()
-            .checked_sub(gc_info.cutoffs.time)
-            .unwrap_or(Lsn(0))
+            .checked_sub(gc_info.cutoffs.time.unwrap_or_default())
+            .unwrap_or_default()
            .0;
        (history, gc_info.within_ancestor_pitr)
    }
@@ -1110,9 +1110,10 @@ impl Timeline {
        self.applied_gc_cutoff_lsn.read()
    }

-    /// Read timeline's planned GC cutoff: this is the logical end of history that users
-    /// are allowed to read (based on configured PITR), even if physically we have more history.
-    pub(crate) fn get_gc_cutoff_lsn(&self) -> Lsn {
+    /// Read timeline's planned GC cutoff: this is the logical end of history that users are allowed
+    /// to read (based on configured PITR), even if physically we have more history. Returns None
+    /// if the PITR cutoff has not yet been initialized.
+    pub(crate) fn get_gc_cutoff_lsn(&self) -> Option<Lsn> {
        self.gc_info.read().unwrap().cutoffs.time
    }

@@ -1563,7 +1564,8 @@ impl Timeline {
                        }
                        WaitLsnWaiter::Tenant
                        | WaitLsnWaiter::PageService
-                        | WaitLsnWaiter::HttpEndpoint => unreachable!(
+                        | WaitLsnWaiter::HttpEndpoint
+                        | WaitLsnWaiter::BaseBackupCache => unreachable!(
                            "tenant or page_service context are not expected to have task kind {:?}",
                            ctx.task_kind()
                        ),
@@ -2468,6 +2470,41 @@ impl Timeline {
            false
        }
    }
+
+    pub(crate) fn is_basebackup_cache_enabled(&self) -> bool {
+        let tenant_conf = self.tenant_conf.load();
+        tenant_conf
+            .tenant_conf
+            .basebackup_cache_enabled
+            .unwrap_or(self.conf.default_tenant_conf.basebackup_cache_enabled)
+    }
+
+    /// Prepare basebackup for the given LSN and store it in the basebackup cache.
+    /// The method is asynchronous and returns immediately.
+    /// The actual basebackup preparation is performed in the background
+    /// by the basebackup cache on a best-effort basis.
+    pub(crate) fn prepare_basebackup(&self, lsn: Lsn) {
+        if !self.is_basebackup_cache_enabled() {
+            return;
+        }
+        if !self.tenant_shard_id.is_shard_zero() {
+            // In theory we should never get here, but just in case check it.
+            // Preparing basebackup doesn't make sense for shards other than shard zero.
+            return;
+        }
+
+        let res = self
+            .basebackup_prepare_sender
+            .send(BasebackupPrepareRequest {
+                tenant_shard_id: self.tenant_shard_id,
+                timeline_id: self.timeline_id,
+                lsn,
+            });
+        if let Err(e) = res {
+            // May happen during shutdown, it's not critical.
+            info!("Failed to send shutdown checkpoint: {e:#}");
+        }
+    }
 }

 /// Number of times we will compute partition within a checkpoint distance.
@@ -2545,6 +2582,13 @@ impl Timeline {
            .unwrap_or(self.conf.default_tenant_conf.checkpoint_timeout)
    }

+    pub(crate) fn get_pitr_interval(&self) -> Duration {
+        let tenant_conf = &self.tenant_conf.load().tenant_conf;
+        tenant_conf
+            .pitr_interval
+            .unwrap_or(self.conf.default_tenant_conf.pitr_interval)
+    }
+
    fn get_compaction_period(&self) -> Duration {
        let tenant_conf = self.tenant_conf.load().tenant_conf.clone();
        tenant_conf
@@ -2820,6 +2864,13 @@ impl Timeline {

            self.remote_client.update_config(&new_conf.location);

+            let mut rel_size_cache = self.rel_size_snapshot_cache.lock().unwrap();
+            if let Some(new_capacity) = new_conf.tenant_conf.relsize_snapshot_cache_capacity {
+                if new_capacity != rel_size_cache.capacity() {
+                    rel_size_cache.set_capacity(new_capacity);
+                }
+            }
+
            self.metrics
                .evictions_with_low_residence_duration
                .write()
@@ -2878,6 +2929,14 @@ impl Timeline {
            ancestor_gc_info.insert_child(timeline_id, metadata.ancestor_lsn(), is_offloaded);
        }

+        let relsize_snapshot_cache_capacity = {
+            let loaded_tenant_conf = tenant_conf.load();
+            loaded_tenant_conf
+                .tenant_conf
+                .relsize_snapshot_cache_capacity
+                .unwrap_or(conf.default_tenant_conf.relsize_snapshot_cache_capacity)
+        };
+
        Arc::new_cyclic(|myself| {
            let metrics = Arc::new(TimelineMetrics::new(
                &tenant_shard_id,
@@ -2969,10 +3028,8 @@ impl Timeline {
                last_image_layer_creation_check_instant: Mutex::new(None),

                last_received_wal: Mutex::new(None),
-                rel_size_cache: RwLock::new(RelSizeCache {
-                    complete_as_of: disk_consistent_lsn,
-                    map: HashMap::new(),
-                }),
+                rel_size_latest_cache: RwLock::new(HashMap::new()),
+                rel_size_snapshot_cache: Mutex::new(LruCache::new(relsize_snapshot_cache_capacity)),

                download_all_remote_layers_task_info: RwLock::new(None),

@@ -3017,6 +3074,10 @@ impl Timeline {
                rel_size_v2_status: ArcSwapOption::from_pointee(rel_size_v2_status),

                wait_lsn_log_slow: tokio::sync::Semaphore::new(1),
+
+                basebackup_prepare_sender: resources.basebackup_prepare_sender,
+
+                feature_resolver: resources.feature_resolver,
            };

            result.repartition_threshold =
@@ -3530,7 +3591,7 @@ impl Timeline {
                };

                let io_concurrency = IoConcurrency::spawn_from_conf(
-                    self_ref.conf,
+                    self_ref.conf.get_vectored_concurrent_io,
                    self_ref
                        .gate
                        .enter()
@@ -4706,7 +4767,10 @@ impl Timeline {
                    || !flushed_to_lsn.is_valid()
            );

-            if flushed_to_lsn < frozen_to_lsn && self.shard_identity.count.count() > 1 {
+            if flushed_to_lsn < frozen_to_lsn
+                && self.shard_identity.count.count() > 1
+                && result.is_ok()
+            {
                // If our layer flushes didn't carry disk_consistent_lsn up to the `to_lsn` advertised
                // to us via layer_flush_start_rx, then advance it here.
                //
@@ -4851,6 +4915,7 @@ impl Timeline {
                    LastImageLayerCreationStatus::Initial,
                    false, // don't yield for L0, we're flushing L0
                )
+                .instrument(info_span!("create_image_layers", mode = %ImageLayerCreationMode::Initial, partition_mode = "initial", lsn = %self.initdb_lsn))
                .await?;
            debug_assert!(
                matches!(is_complete, LastImageLayerCreationStatus::Complete),
@@ -4884,6 +4949,10 @@ impl Timeline {
            return Err(FlushLayerError::Cancelled);
        }

+        fail_point!("flush-layer-before-update-remote-consistent-lsn", |_| {
+            Err(FlushLayerError::Other(anyhow!("failpoint").into()))
+        });
+
        let disk_consistent_lsn = Lsn(lsn_range.end.0 - 1);

        // The new on-disk layers are now in the layer map. We can remove the
@@ -5407,7 +5476,8 @@ impl Timeline {

    /// Returns the image layers generated and an enum indicating whether the process is fully completed.
    /// true = we have generate all image layers, false = we preempt the process for L0 compaction.
-    #[tracing::instrument(skip_all, fields(%lsn, %mode))]
+    ///
+    /// `partition_mode` is only for logging purpose and is not used anywhere in this function.
    async fn create_image_layers(
        self: &Arc<Timeline>,
        partitioning: &KeyPartitioning,
@@ -5559,7 +5629,7 @@ impl Timeline {
            });

            let io_concurrency = IoConcurrency::spawn_from_conf(
-                self.conf,
+                self.conf.get_vectored_concurrent_io,
                self.gate
                    .enter()
                    .map_err(|_| CreateImageLayersError::Cancelled)?,
@@ -6230,14 +6300,12 @@ impl Timeline {

        pausable_failpoint!("Timeline::find_gc_cutoffs-pausable");

-        if cfg!(test) {
+        if cfg!(test) && pitr == Duration::ZERO {
            // Unit tests which specify zero PITR interval expect to avoid doing any I/O for timestamp lookup
-            if pitr == Duration::ZERO {
-                return Ok(GcCutoffs {
-                    time: self.get_last_record_lsn(),
-                    space: space_cutoff,
-                });
-            }
+            return Ok(GcCutoffs {
+                time: Some(self.get_last_record_lsn()),
+                space: space_cutoff,
+            });
        }

        // Calculate a time-based limit on how much to retain:
@@ -6251,14 +6319,14 @@ impl Timeline {
                // PITR is not set. Retain the size-based limit, or the default time retention,
                // whichever requires less data.
                GcCutoffs {
-                    time: self.get_last_record_lsn(),
+                    time: Some(self.get_last_record_lsn()),
                    space: std::cmp::max(time_cutoff, space_cutoff),
                }
            }
            (Duration::ZERO, None) => {
                // PITR is not set, and time lookup failed
                GcCutoffs {
-                    time: self.get_last_record_lsn(),
+                    time: Some(self.get_last_record_lsn()),
                    space: space_cutoff,
                }
            }
@@ -6266,7 +6334,7 @@ impl Timeline {
                // PITR interval is set & we didn't look up a timestamp successfully.  Conservatively assume PITR
                // cannot advance beyond what was already GC'd, and respect space-based retention
                GcCutoffs {
-                    time: *self.get_applied_gc_cutoff_lsn(),
+                    time: Some(*self.get_applied_gc_cutoff_lsn()),
                    space: space_cutoff,
                }
            }
@@ -6274,7 +6342,7 @@ impl Timeline {
                // PITR interval is set and we looked up timestamp successfully.  Ignore
                // size based retention and make time cutoff authoritative
                GcCutoffs {
-                    time: time_cutoff,
+                    time: Some(time_cutoff),
                    space: time_cutoff,
                }
            }
@@ -6327,7 +6395,7 @@ impl Timeline {
            )
        };

-        let mut new_gc_cutoff = Lsn::min(space_cutoff, time_cutoff);
+        let mut new_gc_cutoff = space_cutoff.min(time_cutoff.unwrap_or_default());
        let standby_horizon = self.standby_horizon.load();
        // Hold GC for the standby, but as a safety guard do it only within some
        // reasonable lag.
@@ -6376,7 +6444,7 @@ impl Timeline {
    async fn gc_timeline(
        &self,
        space_cutoff: Lsn,
-        time_cutoff: Lsn,
+        time_cutoff: Option<Lsn>, // None if uninitialized
        retain_lsns: Vec<Lsn>,
        max_lsn_with_valid_lease: Option<Lsn>,
        new_gc_cutoff: Lsn,
@@ -6395,6 +6463,12 @@ impl Timeline {
            return Ok(result);
        }

+        let Some(time_cutoff) = time_cutoff else {
+            // The GC cutoff should have been computed by now, but let's be defensive.
+            info!("Nothing to GC: time_cutoff not yet computed");
+            return Ok(result);
+        };
+
        // We need to ensure that no one tries to read page versions or create
        // branches at a point before latest_gc_cutoff_lsn. See branch_timeline()
        // for details. This will block until the old value is no longer in use.
--- a/pageserver/src/tenant/timeline/compaction.rs
+++ b/pageserver/src/tenant/timeline/compaction.rs
@@ -206,8 +206,8 @@ pub struct GcCompactionQueue {
 }

 static CONCURRENT_GC_COMPACTION_TASKS: Lazy<Arc<Semaphore>> = Lazy::new(|| {
-    // Only allow two timelines on one pageserver to run gc compaction at a time.
-    Arc::new(Semaphore::new(2))
+    // Only allow one timeline on one pageserver to run gc compaction at a time.
+    Arc::new(Semaphore::new(1))
 });

 impl GcCompactionQueue {
@@ -1278,11 +1278,55 @@ impl Timeline {
        }

        let gc_cutoff = *self.applied_gc_cutoff_lsn.read();
+        let l0_l1_boundary_lsn = {
+            // We do the repartition on the L0-L1 boundary. All data below the boundary
+            // are compacted by L0 with low read amplification, thus making the `repartition`
+            // function run fast.
+            let guard = self.layers.read().await;
+            guard
+                .all_persistent_layers()
+                .iter()
+                .map(|x| {
+                    // Use the end LSN of delta layers OR the start LSN of image layers.
+                    if x.is_delta {
+                        x.lsn_range.end
+                    } else {
+                        x.lsn_range.start
+                    }
+                })
+                .max()
+        };
+
+        let (partition_mode, partition_lsn) = if cfg!(test)
+            || cfg!(feature = "testing")
+            || self
+                .feature_resolver
+                .evaluate_boolean("image-compaction-boundary", self.tenant_shard_id.tenant_id)
+                .is_ok()
+        {
+            let last_repartition_lsn = self.partitioning.read().1;
+            let lsn = match l0_l1_boundary_lsn {
+                Some(boundary) => gc_cutoff
+                    .max(boundary)
+                    .max(last_repartition_lsn)
+                    .max(self.initdb_lsn)
+                    .max(self.ancestor_lsn),
+                None => self.get_last_record_lsn(),
+            };
+            if lsn <= self.initdb_lsn || lsn <= self.ancestor_lsn {
+                // Do not attempt to create image layers below the initdb or ancestor LSN -- no data below it
+                ("l0_l1_boundary", self.get_last_record_lsn())
+            } else {
+                ("l0_l1_boundary", lsn)
+            }
+        } else {
+            ("latest_record", self.get_last_record_lsn())
+        };

        // 2. Repartition and create image layers if necessary
        match self
            .repartition(
-                self.get_last_record_lsn(),
+                partition_lsn,
                self.get_compaction_target_size(),
                options.flags,
                ctx,
@@ -1301,18 +1345,19 @@ impl Timeline {
                    .extend(sparse_partitioning.into_dense().parts);

                // 3. Create new image layers for partitions that have been modified "enough".
+                let mode = if options
+                    .flags
+                    .contains(CompactFlags::ForceImageLayerCreation)
+                {
+                    ImageLayerCreationMode::Force
+                } else {
+                    ImageLayerCreationMode::Try
+                };
                let (image_layers, outcome) = self
                    .create_image_layers(
                        &partitioning,
                        lsn,
-                        if options
-                            .flags
-                            .contains(CompactFlags::ForceImageLayerCreation)
-                        {
-                            ImageLayerCreationMode::Force
-                        } else {
-                            ImageLayerCreationMode::Try
-                        },
+                        mode,
                        &image_ctx,
                        self.last_image_layer_creation_status
                            .load()
@@ -1320,6 +1365,7 @@ impl Timeline {
                            .clone(),
                        options.flags.contains(CompactFlags::YieldForL0),
                    )
+                    .instrument(info_span!("create_image_layers", mode = %mode, partition_mode = %partition_mode, lsn = %lsn))
                    .await
                    .inspect_err(|err| {
                        if let CreateImageLayersError::GetVectoredError(
@@ -1344,7 +1390,8 @@ impl Timeline {
            }

            Ok(_) => {
-                info!("skipping repartitioning due to image compaction LSN being below GC cutoff");
+                // This happens very frequently so we don't want to log it.
+                debug!("skipping repartitioning due to image compaction LSN being below GC cutoff");
            }

            // Suppress errors when cancelled.
@@ -1526,7 +1573,7 @@ impl Timeline {
        info!(
            "starting shard ancestor compaction, rewriting {} layers and dropping {} layers, \
                checked {layers_checked}/{layers_total} layers \
-                (latest_gc_cutoff={} pitr_cutoff={})",
+                (latest_gc_cutoff={} pitr_cutoff={:?})",
            layers_to_rewrite.len(),
            drop_layers.len(),
            *latest_gc_cutoff,
--- a/pageserver/src/tenant/timeline/delete.rs
+++ b/pageserver/src/tenant/timeline/delete.rs
@@ -121,6 +121,7 @@ async fn remove_maybe_offloaded_timeline_from_tenant(
    // This observes the locking order between timelines and timelines_offloaded
    let mut timelines = tenant.timelines.lock().unwrap();
    let mut timelines_offloaded = tenant.timelines_offloaded.lock().unwrap();
+    let mut timelines_importing = tenant.timelines_importing.lock().unwrap();
    let offloaded_children_exist = timelines_offloaded
        .iter()
        .any(|(_, entry)| entry.ancestor_timeline_id == Some(timeline.timeline_id()));
@@ -150,8 +151,12 @@ async fn remove_maybe_offloaded_timeline_from_tenant(
                .expect("timeline that we were deleting was concurrently removed from 'timelines_offloaded' map");
            offloaded_timeline.delete_from_ancestor_with_timelines(&timelines);
        }
+        TimelineOrOffloaded::Importing(importing) => {
+            timelines_importing.remove(&importing.timeline.timeline_id);
+        }
    }

+    drop(timelines_importing);
    drop(timelines_offloaded);
    drop(timelines);

@@ -203,8 +208,17 @@ impl DeleteTimelineFlow {
        guard.mark_in_progress()?;

        // Now that the Timeline is in Stopping state, request all the related tasks to shut down.
-        if let TimelineOrOffloaded::Timeline(timeline) = &timeline {
-            timeline.shutdown(super::ShutdownMode::Hard).await;
+        // TODO(vlad): shut down imported timeline here
+        match &timeline {
+            TimelineOrOffloaded::Timeline(timeline) => {
+                timeline.shutdown(super::ShutdownMode::Hard).await;
+            }
+            TimelineOrOffloaded::Importing(importing) => {
+                importing.shutdown().await;
+            }
+            TimelineOrOffloaded::Offloaded(_offloaded) => {
+                // Nothing to shut down in this case
+            }
        }

        tenant.gc_block.before_delete(&timeline.timeline_id());
@@ -389,10 +403,18 @@ impl DeleteTimelineFlow {
            Err(anyhow::anyhow!("failpoint: timeline-delete-before-rm"))?
        });

-        // Offloaded timelines have no local state
-        // TODO: once we persist offloaded information, delete the timeline from there, too
-        if let TimelineOrOffloaded::Timeline(timeline) = timeline {
-            delete_local_timeline_directory(conf, tenant.tenant_shard_id, timeline).await;
+        match timeline {
+            TimelineOrOffloaded::Timeline(timeline) => {
+                delete_local_timeline_directory(conf, tenant.tenant_shard_id, timeline).await;
+            }
+            TimelineOrOffloaded::Importing(importing) => {
+                delete_local_timeline_directory(conf, tenant.tenant_shard_id, &importing.timeline)
+                    .await;
+            }
+            TimelineOrOffloaded::Offloaded(_offloaded) => {
+                // Offloaded timelines have no local state
+                // TODO: once we persist offloaded information, delete the timeline from there, too
+            }
        }

        fail::fail_point!("timeline-delete-after-rm", |_| {
@@ -451,12 +473,16 @@ pub(super) fn make_timeline_delete_guard(
    // For more context see this discussion: `https://github.com/neondatabase/neon/pull/4552#discussion_r1253437346`
    let timelines = tenant.timelines.lock().unwrap();
    let timelines_offloaded = tenant.timelines_offloaded.lock().unwrap();
+    let timelines_importing = tenant.timelines_importing.lock().unwrap();

    let timeline = match timelines.get(&timeline_id) {
        Some(t) => TimelineOrOffloaded::Timeline(Arc::clone(t)),
        None => match timelines_offloaded.get(&timeline_id) {
            Some(t) => TimelineOrOffloaded::Offloaded(Arc::clone(t)),
-            None => return Err(DeleteTimelineError::NotFound),
+            None => match timelines_importing.get(&timeline_id) {
+                Some(t) => TimelineOrOffloaded::Importing(Arc::clone(t)),
+                None => return Err(DeleteTimelineError::NotFound),
+            },
        },
    };

--- a/pageserver/src/tenant/timeline/detach_ancestor.rs
+++ b/pageserver/src/tenant/timeline/detach_ancestor.rs
@@ -188,7 +188,7 @@ pub(crate) async fn generate_tombstone_image_layer(
        "removing non-inherited keys by writing an image layer with tombstones at the detach LSN"
    );
    let io_concurrency = IoConcurrency::spawn_from_conf(
-        detached.conf,
+        detached.conf.get_vectored_concurrent_io,
        detached.gate.enter().map_err(|_| Error::ShuttingDown)?,
    );
    let mut reconstruct_state = ValuesReconstructState::new(io_concurrency);
--- a/pageserver/src/tenant/timeline/import_pgdata.rs
+++ b/pageserver/src/tenant/timeline/import_pgdata.rs
@@ -8,8 +8,10 @@ use tokio::task::JoinHandle;
 use tokio_util::sync::CancellationToken;
 use tracing::info;
 use utils::lsn::Lsn;
+use utils::pausable_failpoint;
+use utils::sync::gate::Gate;

-use super::Timeline;
+use super::{Timeline, TimelineDeleteProgress};
 use crate::context::RequestContext;
 use crate::controller_upcall_client::{StorageControllerUpcallApi, StorageControllerUpcallClient};
 use crate::tenant::metadata::TimelineMetadata;
@@ -19,14 +21,25 @@ mod importbucket_client;
 mod importbucket_format;
 pub(crate) mod index_part_format;

-pub(crate) struct ImportingTimeline {
+pub struct ImportingTimeline {
    pub import_task_handle: JoinHandle<()>,
+    pub import_task_gate: Gate,
    pub timeline: Arc<Timeline>,
+    pub delete_progress: TimelineDeleteProgress,
+}
+
+impl std::fmt::Debug for ImportingTimeline {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "ImportingTimeline<{}>", self.timeline.timeline_id)
+    }
 }

 impl ImportingTimeline {
-    pub(crate) fn shutdown(self) {
+    pub async fn shutdown(&self) {
        self.import_task_handle.abort();
+        self.import_task_gate.close().await;
+
+        self.timeline.remote_client.shutdown().await;
    }
 }

@@ -93,6 +106,13 @@ pub async fn doit(
                );
            }

+            timeline
+                .remote_client
+                .schedule_index_upload_for_file_changes()?;
+            timeline.remote_client.wait_completion().await?;
+
+            pausable_failpoint!("import-timeline-pre-success-notify-pausable");
+
            // Communicate that shard is done.
            // Ensure at-least-once delivery of the upcall to storage controller
            // before we mark the task as done and never come here again.
--- a/pageserver/src/tenant/timeline/import_pgdata/flow.rs
+++ b/pageserver/src/tenant/timeline/import_pgdata/flow.rs
@@ -11,25 +11,14 @@
 //! - => S3 as the source for the PGDATA instead of local filesystem
 //!
 //! TODOs before productionization:
-//! - ChunkProcessingJob size / ImportJob::total_size does not account for sharding.
-//!   => produced image layers likely too small.
 //! - ChunkProcessingJob should cut up an ImportJob to hit exactly target image layer size.
-//! - asserts / unwraps need to be replaced with errors
-//! - don't trust remote objects will be small (=prevent OOMs in those cases)
-//!     - limit all in-memory buffers in size, or download to disk and read from there
-//! - limit task concurrency
-//! - generally play nice with other tenants in the system
-//!   - importbucket is different bucket than main pageserver storage, so, should be fine wrt S3 rate limits
-//!   - but concerns like network bandwidth, local disk write bandwidth, local disk capacity, etc
-//! - integrate with layer eviction system
-//! - audit for Tenant::cancel nor Timeline::cancel responsivity
-//! - audit for Tenant/Timeline gate holding (we spawn tokio tasks during this flow!)
 //!
 //! An incomplete set of TODOs from the Hackathon:
 //! - version-specific CheckPointData (=> pgv abstraction, already exists for regular walingest)

 use std::collections::HashSet;
 use std::hash::{Hash, Hasher};
+use std::num::NonZeroUsize;
 use std::ops::Range;
 use std::sync::Arc;

@@ -43,7 +32,7 @@ use pageserver_api::key::{
    rel_dir_to_key, rel_size_to_key, relmap_file_key, slru_block_to_key, slru_dir_to_key,
    slru_segment_size_to_key,
 };
-use pageserver_api::keyspace::{contiguous_range_len, is_contiguous_range, singleton_range};
+use pageserver_api::keyspace::{ShardedRange, singleton_range};
 use pageserver_api::models::{ShardImportProgress, ShardImportProgressV1, ShardImportStatus};
 use pageserver_api::reltag::{RelTag, SlruKind};
 use pageserver_api::shard::ShardIdentity;
@@ -100,8 +89,24 @@ async fn run_v1(
        tasks: Vec::default(),
    };

-    let import_config = &timeline.conf.timeline_import_config;
-    let plan = planner.plan(import_config).await?;
+    // Use the job size limit encoded in the progress if we are resuming an import.
+    // This ensures that imports have stable plans even if the pageserver config changes.
+    let import_config = {
+        match &import_progress {
+            Some(progress) => {
+                let base = &timeline.conf.timeline_import_config;
+                TimelineImportConfig {
+                    import_job_soft_size_limit: NonZeroUsize::new(progress.job_soft_size_limit)
+                        .unwrap(),
+                    import_job_concurrency: base.import_job_concurrency,
+                    import_job_checkpoint_threshold: base.import_job_checkpoint_threshold,
+                }
+            }
+            None => timeline.conf.timeline_import_config.clone(),
+        }
+    };
+
+    let plan = planner.plan(&import_config).await?;

    // Hash the plan and compare with the hash of the plan we got back from the storage controller.
    // If the two match, it means that the planning stage had the same output.
@@ -113,20 +118,20 @@ async fn run_v1(
    let plan_hash = hasher.finish();

    if let Some(progress) = &import_progress {
-        if plan_hash != progress.import_plan_hash {
-            anyhow::bail!("Import plan does not match storcon metadata");
-        }
-
        // Handle collisions on jobs of unequal length
        if progress.jobs != plan.jobs.len() {
            anyhow::bail!("Import plan job length does not match storcon metadata")
        }
+
+        if plan_hash != progress.import_plan_hash {
+            anyhow::bail!("Import plan does not match storcon metadata");
+        }
    }

    pausable_failpoint!("import-timeline-pre-execute-pausable");

    let start_from_job_idx = import_progress.map(|progress| progress.completed);
-    plan.execute(timeline, start_from_job_idx, plan_hash, import_config, ctx)
+    plan.execute(timeline, start_from_job_idx, plan_hash, &import_config, ctx)
        .await
 }

@@ -150,6 +155,7 @@ impl Planner {
    /// This function is and must remain pure: given the same input, it will generate the same import plan.
    async fn plan(mut self, import_config: &TimelineImportConfig) -> anyhow::Result<Plan> {
        let pgdata_lsn = Lsn(self.control_file.control_file_data().checkPoint).align();
+        anyhow::ensure!(pgdata_lsn.is_valid());

        let datadir = PgDataDir::new(&self.storage).await?;

@@ -218,15 +224,36 @@ impl Planner {
                checkpoint_buf,
            )));

+        // Sort the tasks by the key ranges they handle.
+        // The plan being generated here needs to be stable across invocations
+        // of this method.
+        self.tasks.sort_by_key(|task| match task {
+            AnyImportTask::SingleKey(key) => (key.key, key.key.next()),
+            AnyImportTask::RelBlocks(rel_blocks) => {
+                (rel_blocks.key_range.start, rel_blocks.key_range.end)
+            }
+            AnyImportTask::SlruBlocks(slru_blocks) => {
+                (slru_blocks.key_range.start, slru_blocks.key_range.end)
+            }
+        });
+
        // Assigns parts of key space to later parallel jobs
+        // Note: The image layers produced here may have gaps, meaning,
+        //       there is not an image for each key in the layer's key range.
+        //       The read path stops traversal at the first image layer, regardless
+        //       of whether a base image has been found for a key or not.
+        //       (Concept of sparse image layers doesn't exist.)
+        //       This behavior is exactly right for the base image layers we're producing here.
+        //       But, since no other place in the code currently produces image layers with gaps,
+        //       it seems noteworthy.
        let mut last_end_key = Key::MIN;
        let mut current_chunk = Vec::new();
        let mut current_chunk_size: usize = 0;
        let mut jobs = Vec::new();
        for task in std::mem::take(&mut self.tasks).into_iter() {
-            if current_chunk_size + task.total_size()
-                > import_config.import_job_soft_size_limit.into()
-            {
+            let task_size = task.total_size(&self.shard);
+            let projected_chunk_size = current_chunk_size.saturating_add(task_size);
+            if projected_chunk_size > import_config.import_job_soft_size_limit.into() {
                let key_range = last_end_key..task.key_range().start;
                jobs.push(ChunkProcessingJob::new(
                    key_range.clone(),
@@ -236,7 +263,7 @@ impl Planner {
                last_end_key = key_range.end;
                current_chunk_size = 0;
            }
-            current_chunk_size += task.total_size();
+            current_chunk_size = current_chunk_size.saturating_add(task_size);
            current_chunk.push(task);
        }
        jobs.push(ChunkProcessingJob::new(
@@ -426,6 +453,8 @@ impl Plan {
                    }));
                },
                maybe_complete_job_idx = work.next() => {
+                    pausable_failpoint!("import-task-complete-pausable");
+
                    match maybe_complete_job_idx {
                        Some(Ok((job_idx, res))) => {
                            assert!(last_completed_job_idx.checked_add(1).unwrap() == job_idx);
@@ -438,8 +467,12 @@ impl Plan {
                                    jobs: jobs_in_plan,
                                    completed: last_completed_job_idx,
                                    import_plan_hash,
+                                    job_soft_size_limit: import_config.import_job_soft_size_limit.into(),
                                };

+                                timeline.remote_client.schedule_index_upload_for_file_changes()?;
+                                timeline.remote_client.wait_completion().await?;
+
                                storcon_client.put_timeline_import_status(
                                    timeline.tenant_shard_id,
                                    timeline.timeline_id,
@@ -568,18 +601,18 @@ impl PgDataDirDb {
                };

                let path = datadir_path.join(rel_tag.to_segfile_name(segno));
-                assert!(filesize % BLCKSZ as usize == 0); // TODO: this should result in an error
+                anyhow::ensure!(filesize % BLCKSZ as usize == 0);
                let nblocks = filesize / BLCKSZ as usize;

-                PgDataDirDbFile {
+                Ok(PgDataDirDbFile {
                    path,
                    filesize,
                    rel_tag,
                    segno,
                    nblocks: Some(nblocks), // first non-cummulative sizes
-                }
+                })
            })
-            .collect();
+            .collect::<anyhow::Result<_, _>>()?;

        // Set cummulative sizes. Do all of that math here, so that later we could easier
        // parallelize over segments and know with which segments we need to write relsize
@@ -614,12 +647,22 @@ impl PgDataDirDb {
 trait ImportTask {
    fn key_range(&self) -> Range<Key>;

-    fn total_size(&self) -> usize {
-        // TODO: revisit this
-        if is_contiguous_range(&self.key_range()) {
-            contiguous_range_len(&self.key_range()) as usize * 8192
+    fn total_size(&self, shard_identity: &ShardIdentity) -> usize {
+        let range = ShardedRange::new(self.key_range(), shard_identity);
+        let page_count = range.page_count();
+        if page_count == u32::MAX {
+            tracing::warn!(
+                "Import task has non contiguous key range: {}..{}",
+                self.key_range().start,
+                self.key_range().end
+            );
+
+            // Tasks should operate on contiguous ranges. It is unexpected for
+            // ranges to violate this assumption. Calling code handles this by mapping
+            // any task on a non contiguous range to its own image layer.
+            usize::MAX
        } else {
-            u32::MAX as usize
+            page_count as usize * 8192
        }
    }

@@ -640,7 +683,11 @@ impl Hash for ImportSingleKeyTask {
        let ImportSingleKeyTask { key, buf } = self;

        key.hash(state);
-        buf.hash(state);
+        // The key value might not have a stable binary representation.
+        // For instance, the db directory uses an unstable hash-map.
+        // To work around this we are a bit lax here and only hash the
+        // size of the buffer which must be consistent.
+        buf.len().hash(state);
    }
 }

@@ -713,6 +760,8 @@ impl ImportTask for ImportRelBlocksTask {
        layer_writer: &mut ImageLayerWriter,
        ctx: &RequestContext,
    ) -> anyhow::Result<usize> {
+        const MAX_BYTE_RANGE_SIZE: usize = 128 * 1024 * 1024;
+
        debug!("Importing relation file");

        let (rel_tag, start_blk) = self.key_range.start.to_rel_block()?;
@@ -737,7 +786,7 @@ impl ImportTask for ImportRelBlocksTask {
                assert_eq!(key.len(), 1);
                assert!(!acc.is_empty());
                assert!(acc_end > acc_start);
-                if acc_end == start /* TODO additional max range check here, to limit memory consumption per task to X */ {
+                if acc_end == start && end - acc_start <= MAX_BYTE_RANGE_SIZE {
                    acc.push(key.pop().unwrap());
                    Ok((acc, acc_start, end))
                } else {
@@ -752,8 +801,8 @@ impl ImportTask for ImportRelBlocksTask {
                .get_range(&self.path, range_start.into_u64(), range_end.into_u64())
                .await?;
            let mut buf = Bytes::from(range_buf);
-            // TODO: batched writes
            for key in keys {
+                // The writer buffers writes internally
                let image = buf.split_to(8192);
                layer_writer.put_image(key, image, ctx).await?;
                nimages += 1;
@@ -806,6 +855,9 @@ impl ImportTask for ImportSlruBlocksTask {
        debug!("Importing SLRU segment file {}", self.path);
        let buf = self.storage.get(&self.path).await?;

+        // TODO(vlad): Does timestamp to LSN work for imported timelines?
+        // Probably not since we don't append the `xact_time` to it as in
+        // [`WalIngest::ingest_xact_record`].
        let (kind, segno, start_blk) = self.key_range.start.to_slru_block()?;
        let (_kind, _segno, end_blk) = self.key_range.end.to_slru_block()?;
        let mut blknum = start_blk;
@@ -915,7 +967,7 @@ impl ChunkProcessingJob {
                let guard = timeline.layers.read().await;
                let existing_layer = guard.try_get_from_key(&desc.key());
                if let Some(layer) = existing_layer {
-                    if layer.metadata().generation != timeline.generation {
+                    if layer.metadata().generation == timeline.generation {
                        return Err(anyhow::anyhow!(
                            "Import attempted to rewrite layer file in the same generation: {}",
                            layer.local_path()
@@ -942,6 +994,15 @@ impl ChunkProcessingJob {
            .cloned();
        match existing_layer {
            Some(existing) => {
+                // Unlink the remote layer from the index without scheduling its deletion.
+                // When `existing_layer` drops [`LayerInner::drop`] will schedule its deletion from
+                // remote storage, but that assumes that the layer was unlinked from the index first.
+                timeline
+                    .remote_client
+                    .schedule_unlinking_of_layers_from_index_part(std::iter::once(
+                        existing.layer_desc().layer_name(),
+                    ))?;
+
                guard.open_mut()?.rewrite_layers(
                    &[(existing.clone(), resident_layer.clone())],
                    &[],
--- a/pageserver/src/tenant/timeline/import_pgdata/importbucket_client.rs
+++ b/pageserver/src/tenant/timeline/import_pgdata/importbucket_client.rs
@@ -6,7 +6,7 @@ use bytes::Bytes;
 use postgres_ffi::ControlFileData;
 use remote_storage::{
    Download, DownloadError, DownloadKind, DownloadOpts, GenericRemoteStorage, Listing,
-    ListingObject, RemotePath,
+    ListingObject, RemotePath, RemoteStorageConfig,
 };
 use serde::de::DeserializeOwned;
 use tokio_util::sync::CancellationToken;
@@ -22,11 +22,9 @@ pub async fn new(
    location: &index_part_format::Location,
    cancel: CancellationToken,
 ) -> Result<RemoteStorageWrapper, anyhow::Error> {
-    // FIXME: we probably want some timeout, and we might be able to assume the max file
-    // size on S3 is 1GiB (postgres segment size). But the problem is that the individual
-    // downloaders don't know enough about concurrent downloads to make a guess on the
-    // expected bandwidth and resulting best timeout.
-    let timeout = std::time::Duration::from_secs(24 * 60 * 60);
+    // Downloads should be reasonably sized. We do ranged reads for relblock raw data
+    // and full reads for SLRU segments which are bounded by Postgres.
+    let timeout = RemoteStorageConfig::DEFAULT_TIMEOUT;
    let location_storage = match location {
        #[cfg(feature = "testing")]
        index_part_format::Location::LocalFs { path } => {
@@ -50,9 +48,12 @@ pub async fn new(
                            .import_pgdata_aws_endpoint_url
                            .clone()
                            .map(|url| url.to_string()), //  by specifying None here, remote_storage/aws-sdk-rust will infer from env
-                        concurrency_limit: 100.try_into().unwrap(), // TODO: think about this
-                        max_keys_per_list_response: Some(1000),     // TODO: think about this
-                        upload_storage_class: None,                 // irrelevant
+                        // This matches the default import job concurrency. This is managed
+                        // separately from the usual S3 client, but the concern here is bandwidth
+                        // usage.
+                        concurrency_limit: 128.try_into().unwrap(),
+                        max_keys_per_list_response: Some(1000),
+                        upload_storage_class: None, // irrelevant
                    },
                    timeout,
                )
--- a/pageserver/src/walingest.rs
+++ b/pageserver/src/walingest.rs
@@ -1316,6 +1316,10 @@ impl WalIngest {
            }
        });

+        if info == pg_constants::XLOG_CHECKPOINT_SHUTDOWN {
+            modification.tline.prepare_basebackup(lsn);
+        }
+
        Ok(())
    }

@@ -1684,31 +1688,31 @@ mod tests {
        // The relation was created at LSN 2, not visible at LSN 1 yet.
        assert_eq!(
            tline
-                .get_rel_exists(TESTREL_A, Version::Lsn(Lsn(0x10)), &ctx)
+                .get_rel_exists(TESTREL_A, Version::at(Lsn(0x10)), &ctx)
                .await?,
            false
        );
        assert!(
            tline
-                .get_rel_size(TESTREL_A, Version::Lsn(Lsn(0x10)), &ctx)
+                .get_rel_size(TESTREL_A, Version::at(Lsn(0x10)), &ctx)
                .await
                .is_err()
        );
        assert_eq!(
            tline
-                .get_rel_exists(TESTREL_A, Version::Lsn(Lsn(0x20)), &ctx)
+                .get_rel_exists(TESTREL_A, Version::at(Lsn(0x20)), &ctx)
                .await?,
            true
        );
        assert_eq!(
            tline
-                .get_rel_size(TESTREL_A, Version::Lsn(Lsn(0x20)), &ctx)
+                .get_rel_size(TESTREL_A, Version::at(Lsn(0x20)), &ctx)
                .await?,
            1
        );
        assert_eq!(
            tline
-                .get_rel_size(TESTREL_A, Version::Lsn(Lsn(0x50)), &ctx)
+                .get_rel_size(TESTREL_A, Version::at(Lsn(0x50)), &ctx)
                .await?,
            3
        );
@@ -1719,7 +1723,7 @@ mod tests {
                .get_rel_page_at_lsn(
                    TESTREL_A,
                    0,
-                    Version::Lsn(Lsn(0x20)),
+                    Version::at(Lsn(0x20)),
                    &ctx,
                    io_concurrency.clone()
                )
@@ -1733,7 +1737,7 @@ mod tests {
                .get_rel_page_at_lsn(
                    TESTREL_A,
                    0,
-                    Version::Lsn(Lsn(0x30)),
+                    Version::at(Lsn(0x30)),
                    &ctx,
                    io_concurrency.clone()
                )
@@ -1747,7 +1751,7 @@ mod tests {
                .get_rel_page_at_lsn(
                    TESTREL_A,
                    0,
-                    Version::Lsn(Lsn(0x40)),
+                    Version::at(Lsn(0x40)),
                    &ctx,
                    io_concurrency.clone()
                )
@@ -1760,7 +1764,7 @@ mod tests {
                .get_rel_page_at_lsn(
                    TESTREL_A,
                    1,
-                    Version::Lsn(Lsn(0x40)),
+                    Version::at(Lsn(0x40)),
                    &ctx,
                    io_concurrency.clone()
                )
@@ -1774,7 +1778,7 @@ mod tests {
                .get_rel_page_at_lsn(
                    TESTREL_A,
                    0,
-                    Version::Lsn(Lsn(0x50)),
+                    Version::at(Lsn(0x50)),
                    &ctx,
                    io_concurrency.clone()
                )
@@ -1787,7 +1791,7 @@ mod tests {
                .get_rel_page_at_lsn(
                    TESTREL_A,
                    1,
-                    Version::Lsn(Lsn(0x50)),
+                    Version::at(Lsn(0x50)),
                    &ctx,
                    io_concurrency.clone()
                )
@@ -1800,7 +1804,7 @@ mod tests {
                .get_rel_page_at_lsn(
                    TESTREL_A,
                    2,
-                    Version::Lsn(Lsn(0x50)),
+                    Version::at(Lsn(0x50)),
                    &ctx,
                    io_concurrency.clone()
                )
@@ -1820,7 +1824,7 @@ mod tests {
        // Check reported size and contents after truncation
        assert_eq!(
            tline
-                .get_rel_size(TESTREL_A, Version::Lsn(Lsn(0x60)), &ctx)
+                .get_rel_size(TESTREL_A, Version::at(Lsn(0x60)), &ctx)
                .await?,
            2
        );
@@ -1829,7 +1833,7 @@ mod tests {
                .get_rel_page_at_lsn(
                    TESTREL_A,
                    0,
-                    Version::Lsn(Lsn(0x60)),
+                    Version::at(Lsn(0x60)),
                    &ctx,
                    io_concurrency.clone()
                )
@@ -1842,7 +1846,7 @@ mod tests {
                .get_rel_page_at_lsn(
                    TESTREL_A,
                    1,
-                    Version::Lsn(Lsn(0x60)),
+                    Version::at(Lsn(0x60)),
                    &ctx,
                    io_concurrency.clone()
                )
@@ -1854,7 +1858,7 @@ mod tests {
        // should still see the truncated block with older LSN
        assert_eq!(
            tline
-                .get_rel_size(TESTREL_A, Version::Lsn(Lsn(0x50)), &ctx)
+                .get_rel_size(TESTREL_A, Version::at(Lsn(0x50)), &ctx)
                .await?,
            3
        );
@@ -1863,7 +1867,7 @@ mod tests {
                .get_rel_page_at_lsn(
                    TESTREL_A,
                    2,
-                    Version::Lsn(Lsn(0x50)),
+                    Version::at(Lsn(0x50)),
                    &ctx,
                    io_concurrency.clone()
                )
@@ -1880,7 +1884,7 @@ mod tests {
        m.commit(&ctx).await?;
        assert_eq!(
            tline
-                .get_rel_size(TESTREL_A, Version::Lsn(Lsn(0x68)), &ctx)
+                .get_rel_size(TESTREL_A, Version::at(Lsn(0x68)), &ctx)
                .await?,
            0
        );
@@ -1893,7 +1897,7 @@ mod tests {
        m.commit(&ctx).await?;
        assert_eq!(
            tline
-                .get_rel_size(TESTREL_A, Version::Lsn(Lsn(0x70)), &ctx)
+                .get_rel_size(TESTREL_A, Version::at(Lsn(0x70)), &ctx)
                .await?,
            2
        );
@@ -1902,7 +1906,7 @@ mod tests {
                .get_rel_page_at_lsn(
                    TESTREL_A,
                    0,
-                    Version::Lsn(Lsn(0x70)),
+                    Version::at(Lsn(0x70)),
                    &ctx,
                    io_concurrency.clone()
                )
@@ -1915,7 +1919,7 @@ mod tests {
                .get_rel_page_at_lsn(
                    TESTREL_A,
                    1,
-                    Version::Lsn(Lsn(0x70)),
+                    Version::at(Lsn(0x70)),
                    &ctx,
                    io_concurrency.clone()
                )
@@ -1932,7 +1936,7 @@ mod tests {
        m.commit(&ctx).await?;
        assert_eq!(
            tline
-                .get_rel_size(TESTREL_A, Version::Lsn(Lsn(0x80)), &ctx)
+                .get_rel_size(TESTREL_A, Version::at(Lsn(0x80)), &ctx)
                .await?,
            1501
        );
@@ -1942,7 +1946,7 @@ mod tests {
                    .get_rel_page_at_lsn(
                        TESTREL_A,
                        blk,
-                        Version::Lsn(Lsn(0x80)),
+                        Version::at(Lsn(0x80)),
                        &ctx,
                        io_concurrency.clone()
                    )
@@ -1956,7 +1960,7 @@ mod tests {
                .get_rel_page_at_lsn(
                    TESTREL_A,
                    1500,
-                    Version::Lsn(Lsn(0x80)),
+                    Version::at(Lsn(0x80)),
                    &ctx,
                    io_concurrency.clone()
                )
@@ -1990,13 +1994,13 @@ mod tests {
        // Check that rel exists and size is correct
        assert_eq!(
            tline
-                .get_rel_exists(TESTREL_A, Version::Lsn(Lsn(0x20)), &ctx)
+                .get_rel_exists(TESTREL_A, Version::at(Lsn(0x20)), &ctx)
                .await?,
            true
        );
        assert_eq!(
            tline
-                .get_rel_size(TESTREL_A, Version::Lsn(Lsn(0x20)), &ctx)
+                .get_rel_size(TESTREL_A, Version::at(Lsn(0x20)), &ctx)
                .await?,
            1
        );
@@ -2011,7 +2015,7 @@ mod tests {
        // Check that rel is not visible anymore
        assert_eq!(
            tline
-                .get_rel_exists(TESTREL_A, Version::Lsn(Lsn(0x30)), &ctx)
+                .get_rel_exists(TESTREL_A, Version::at(Lsn(0x30)), &ctx)
                .await?,
            false
        );
@@ -2029,13 +2033,13 @@ mod tests {
        // Check that rel exists and size is correct
        assert_eq!(
            tline
-                .get_rel_exists(TESTREL_A, Version::Lsn(Lsn(0x40)), &ctx)
+                .get_rel_exists(TESTREL_A, Version::at(Lsn(0x40)), &ctx)
                .await?,
            true
        );
        assert_eq!(
            tline
-                .get_rel_size(TESTREL_A, Version::Lsn(Lsn(0x40)), &ctx)
+                .get_rel_size(TESTREL_A, Version::at(Lsn(0x40)), &ctx)
                .await?,
            1
        );
@@ -2077,26 +2081,26 @@ mod tests {
        // The relation was created at LSN 20, not visible at LSN 1 yet.
        assert_eq!(
            tline
-                .get_rel_exists(TESTREL_A, Version::Lsn(Lsn(0x10)), &ctx)
+                .get_rel_exists(TESTREL_A, Version::at(Lsn(0x10)), &ctx)
                .await?,
            false
        );
        assert!(
            tline
-                .get_rel_size(TESTREL_A, Version::Lsn(Lsn(0x10)), &ctx)
+                .get_rel_size(TESTREL_A, Version::at(Lsn(0x10)), &ctx)
                .await
                .is_err()
        );

        assert_eq!(
            tline
-                .get_rel_exists(TESTREL_A, Version::Lsn(Lsn(0x20)), &ctx)
+                .get_rel_exists(TESTREL_A, Version::at(Lsn(0x20)), &ctx)
                .await?,
            true
        );
        assert_eq!(
            tline
-                .get_rel_size(TESTREL_A, Version::Lsn(Lsn(0x20)), &ctx)
+                .get_rel_size(TESTREL_A, Version::at(Lsn(0x20)), &ctx)
                .await?,
            relsize
        );
@@ -2110,7 +2114,7 @@ mod tests {
                    .get_rel_page_at_lsn(
                        TESTREL_A,
                        blkno,
-                        Version::Lsn(lsn),
+                        Version::at(lsn),
                        &ctx,
                        io_concurrency.clone()
                    )
@@ -2131,7 +2135,7 @@ mod tests {
        // Check reported size and contents after truncation
        assert_eq!(
            tline
-                .get_rel_size(TESTREL_A, Version::Lsn(Lsn(0x60)), &ctx)
+                .get_rel_size(TESTREL_A, Version::at(Lsn(0x60)), &ctx)
                .await?,
            1
        );
@@ -2144,7 +2148,7 @@ mod tests {
                    .get_rel_page_at_lsn(
                        TESTREL_A,
                        blkno,
-                        Version::Lsn(Lsn(0x60)),
+                        Version::at(Lsn(0x60)),
                        &ctx,
                        io_concurrency.clone()
                    )
@@ -2157,7 +2161,7 @@ mod tests {
        // should still see all blocks with older LSN
        assert_eq!(
            tline
-                .get_rel_size(TESTREL_A, Version::Lsn(Lsn(0x50)), &ctx)
+                .get_rel_size(TESTREL_A, Version::at(Lsn(0x50)), &ctx)
                .await?,
            relsize
        );
@@ -2169,7 +2173,7 @@ mod tests {
                    .get_rel_page_at_lsn(
                        TESTREL_A,
                        blkno,
-                        Version::Lsn(Lsn(0x50)),
+                        Version::at(Lsn(0x50)),
                        &ctx,
                        io_concurrency.clone()
                    )
@@ -2193,13 +2197,13 @@ mod tests {

        assert_eq!(
            tline
-                .get_rel_exists(TESTREL_A, Version::Lsn(Lsn(0x80)), &ctx)
+                .get_rel_exists(TESTREL_A, Version::at(Lsn(0x80)), &ctx)
                .await?,
            true
        );
        assert_eq!(
            tline
-                .get_rel_size(TESTREL_A, Version::Lsn(Lsn(0x80)), &ctx)
+                .get_rel_size(TESTREL_A, Version::at(Lsn(0x80)), &ctx)
                .await?,
            relsize
        );
@@ -2212,7 +2216,7 @@ mod tests {
                    .get_rel_page_at_lsn(
                        TESTREL_A,
                        blkno,
-                        Version::Lsn(Lsn(0x80)),
+                        Version::at(Lsn(0x80)),
                        &ctx,
                        io_concurrency.clone()
                    )
@@ -2250,7 +2254,7 @@ mod tests {

        assert_eq!(
            tline
-                .get_rel_size(TESTREL_A, Version::Lsn(Lsn(lsn)), &ctx)
+                .get_rel_size(TESTREL_A, Version::at(Lsn(lsn)), &ctx)
                .await?,
            RELSEG_SIZE + 1
        );
@@ -2264,7 +2268,7 @@ mod tests {
        m.commit(&ctx).await?;
        assert_eq!(
            tline
-                .get_rel_size(TESTREL_A, Version::Lsn(Lsn(lsn)), &ctx)
+                .get_rel_size(TESTREL_A, Version::at(Lsn(lsn)), &ctx)
                .await?,
            RELSEG_SIZE
        );
@@ -2279,7 +2283,7 @@ mod tests {
        m.commit(&ctx).await?;
        assert_eq!(
            tline
-                .get_rel_size(TESTREL_A, Version::Lsn(Lsn(lsn)), &ctx)
+                .get_rel_size(TESTREL_A, Version::at(Lsn(lsn)), &ctx)
                .await?,
            RELSEG_SIZE - 1
        );
@@ -2297,7 +2301,7 @@ mod tests {
            m.commit(&ctx).await?;
            assert_eq!(
                tline
-                    .get_rel_size(TESTREL_A, Version::Lsn(Lsn(lsn)), &ctx)
+                    .get_rel_size(TESTREL_A, Version::at(Lsn(lsn)), &ctx)
                    .await?,
                size as BlockNumber
            );
--- a/pgxn/neon/communicator.c
+++ b/pgxn/neon/communicator.c
@@ -717,7 +717,7 @@ prefetch_read(PrefetchRequest *slot)
 	Assert(slot->status == PRFS_REQUESTED);
 	Assert(slot->response == NULL);
 	Assert(slot->my_ring_index == MyPState->ring_receive);
-	Assert(readpage_reentrant_guard);
+	Assert(readpage_reentrant_guard || AmPrewarmWorker);

 	if (slot->status != PRFS_REQUESTED ||
 		slot->response != NULL ||
@@ -800,7 +800,7 @@ communicator_prefetch_receive(BufferTag tag)
 	PrfHashEntry *entry;
 	PrefetchRequest hashkey;

-	Assert(readpage_reentrant_guard);
+	Assert(readpage_reentrant_guard || AmPrewarmWorker); /* do not pump prefetch state in prewarm worker */
 	hashkey.buftag = tag;
 	entry = prfh_lookup(MyPState->prf_hash, &hashkey);
 	if (entry != NULL && prefetch_wait_for(entry->slot->my_ring_index))
@@ -2450,6 +2450,7 @@ void
 communicator_reconfigure_timeout_if_needed(void)
 {
 	bool	needs_set = MyPState->ring_receive != MyPState->ring_unused &&
+						!AmPrewarmWorker && /* do not pump prefetch state in prewarm worker */
 						readahead_getpage_pull_timeout_ms > 0;

 	if (needs_set != timeout_set)
--- a/pgxn/neon/file_cache.c
+++ b/pgxn/neon/file_cache.c
@@ -201,6 +201,8 @@ static shmem_request_hook_type prev_shmem_request_hook;
 bool lfc_store_prefetch_result;
 bool lfc_prewarm_update_ws_estimation;

+bool AmPrewarmWorker;
+
 #define LFC_ENABLED() (lfc_ctl->limit != 0)

 /*
@@ -845,6 +847,8 @@ lfc_prewarm_main(Datum main_arg)
 	PrewarmWorkerState* ws;
 	uint32 worker_id = DatumGetInt32(main_arg);

+	AmPrewarmWorker = true;
+
 	pqsignal(SIGTERM, die);
 	BackgroundWorkerUnblockSignals();

--- a/pgxn/neon/neon.h
+++ b/pgxn/neon/neon.h
@@ -23,6 +23,8 @@ extern int	wal_acceptor_connection_timeout;
 extern int	readahead_getpage_pull_timeout_ms;
 extern bool	disable_wal_prev_lsn_checks;

+extern bool AmPrewarmWorker;
+
 #if PG_MAJORVERSION_NUM >= 17
 extern uint32		WAIT_EVENT_NEON_LFC_MAINTENANCE;
 extern uint32		WAIT_EVENT_NEON_LFC_READ;
--- a/pgxn/neon/neon_pgversioncompat.h
+++ b/pgxn/neon/neon_pgversioncompat.h
@@ -86,7 +86,7 @@ InitBufferTag(BufferTag *tag, const RelFileNode *rnode,

 #define InvalidRelFileNumber InvalidOid

-#define SMgrRelGetRelInfo(reln) \
+#define SMgrRelGetRelInfo(reln)				\
 	(reln->smgr_rnode.node)

 #define DropRelationAllLocalBuffers DropRelFileNodeAllLocalBuffers
@@ -148,6 +148,12 @@ InitBufferTag(BufferTag *tag, const RelFileNode *rnode,
 #define DropRelationAllLocalBuffers DropRelationAllLocalBuffers
 #endif

+#define NRelFileInfoInvalidate(rinfo) do { \
+		NInfoGetSpcOid(rinfo) = InvalidOid; \
+		NInfoGetDbOid(rinfo) = InvalidOid; \
+		NInfoGetRelNumber(rinfo) = InvalidRelFileNumber; \
+	} while (0)
+
 #if PG_MAJORVERSION_NUM < 17
 #define ProcNumber BackendId
 #define INVALID_PROC_NUMBER InvalidBackendId
--- a/pgxn/neon/pagestore_smgr.c
+++ b/pgxn/neon/pagestore_smgr.c
@@ -108,7 +108,7 @@ typedef enum
 	UNLOGGED_BUILD_NOT_PERMANENT
 } UnloggedBuildPhase;

-static SMgrRelation unlogged_build_rel = NULL;
+static NRelFileInfo unlogged_build_rel_info;
 static UnloggedBuildPhase unlogged_build_phase = UNLOGGED_BUILD_NOT_IN_PROGRESS;

 static bool neon_redo_read_buffer_filter(XLogReaderState *record, uint8 block_id);
@@ -912,8 +912,14 @@ neon_extend(SMgrRelation reln, ForkNumber forkNum, BlockNumber blkno,
 	{
 		case 0:
 			neon_log(ERROR, "cannot call smgrextend() on rel with unknown persistence");
+			break;

 		case RELPERSISTENCE_PERMANENT:
+			if (RelFileInfoEquals(unlogged_build_rel_info, InfoFromSMgrRel(reln)))
+			{
+				mdextend(reln, forkNum, blkno, buffer, skipFsync);
+				return;
+			}
 			break;

 		case RELPERSISTENCE_TEMP:
@@ -1000,8 +1006,14 @@ neon_zeroextend(SMgrRelation reln, ForkNumber forkNum, BlockNumber blocknum,
 	{
 		case 0:
 			neon_log(ERROR, "cannot call smgrextend() on rel with unknown persistence");
+			break;

 		case RELPERSISTENCE_PERMANENT:
+			if (RelFileInfoEquals(unlogged_build_rel_info, InfoFromSMgrRel(reln)))
+			{
+				mdzeroextend(reln, forkNum, blocknum, nblocks, skipFsync);
+				return;
+			}
 			break;

 		case RELPERSISTENCE_TEMP:
@@ -1376,8 +1388,14 @@ neon_read(SMgrRelation reln, ForkNumber forkNum, BlockNumber blkno, void *buffer
 	{
 		case 0:
 			neon_log(ERROR, "cannot call smgrread() on rel with unknown persistence");
+			break;

 		case RELPERSISTENCE_PERMANENT:
+			if (RelFileInfoEquals(unlogged_build_rel_info, InfoFromSMgrRel(reln)))
+			{
+				mdread(reln, forkNum, blkno, buffer);
+				return;
+			}
 			break;

 		case RELPERSISTENCE_TEMP:
@@ -1463,8 +1481,14 @@ neon_readv(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
 	{
 		case 0:
 			neon_log(ERROR, "cannot call smgrread() on rel with unknown persistence");
+			break;

 		case RELPERSISTENCE_PERMANENT:
+			if (RelFileInfoEquals(unlogged_build_rel_info, InfoFromSMgrRel(reln)))
+			{
+				mdreadv(reln, forknum, blocknum, buffers, nblocks);
+				return;
+			}
 			break;

 		case RELPERSISTENCE_TEMP:
@@ -1580,25 +1604,38 @@ neon_write(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum, const vo
 #endif
 			{
 				/* It exists locally. Guess it's unlogged then. */
+				if (mdnblocks(reln, forknum) >= blocknum)
+				{
+					/* prevent race condition with unlogged build end which unlinks local files */
+#if PG_MAJORVERSION_NUM >= 17
+					mdwritev(reln, forknum, blocknum, &buffer, 1, skipFsync);
+#else
+					mdwrite(reln, forknum, blocknum, buffer, skipFsync);
+#endif
+					/*
+					 * We could set relpersistence now that we have determined
+					 * that it's local. But we don't dare to do it, because that
+					 * would immediately allow reads as well, which shouldn't
+					 * happen. We could cache it with a different 'relpersistence'
+					 * value, but this isn't performance critical.
+					 */
+					return;
+				}
+			}
+			break;
+
+		case RELPERSISTENCE_PERMANENT:
+			if (RelFileInfoEquals(unlogged_build_rel_info, InfoFromSMgrRel(reln)))
+			{
 #if PG_MAJORVERSION_NUM >= 17
 				mdwritev(reln, forknum, blocknum, &buffer, 1, skipFsync);
 #else
 				mdwrite(reln, forknum, blocknum, buffer, skipFsync);
 #endif
-				/*
-				 * We could set relpersistence now that we have determined
-				 * that it's local. But we don't dare to do it, because that
-				 * would immediately allow reads as well, which shouldn't
-				 * happen. We could cache it with a different 'relpersistence'
-				 * value, but this isn't performance critical.
-				 */
 				return;
 			}
 			break;

-		case RELPERSISTENCE_PERMANENT:
-			break;
-
 		case RELPERSISTENCE_TEMP:
 		case RELPERSISTENCE_UNLOGGED:
 			#if PG_MAJORVERSION_NUM >= 17
@@ -1651,21 +1688,39 @@ neon_writev(SMgrRelation reln, ForkNumber forknum, BlockNumber blkno,
 			if (mdexists(reln, INIT_FORKNUM))
 #endif
 			{
-				/* It exists locally. Guess it's unlogged then. */
-				mdwritev(reln, forknum, blkno, buffers, nblocks, skipFsync);
-
 				/*
-				 * We could set relpersistence now that we have determined
-				 * that it's local. But we don't dare to do it, because that
-				 * would immediately allow reads as well, which shouldn't
-				 * happen. We could cache it with a different 'relpersistence'
-				 * value, but this isn't performance critical.
+				 * There can be race condition between backend A performing unlogged index build and some other backend B evicting page of this index.
+				 * After `mdexists` check in backend B is completed and returns true, backend A can complete unlogged build and unlink local files
+				 * of this relation before backend B performs `mdwrite`. It is not a problem if unlogged relation has just one segment:
+				 * it is opened and file descriptor is cached by smgr, preventing removing file on the disk. So subsequent `mdwrite` will succeed.
+				 * But if unlogged relation is large enough and consists of multiple segments, then first segment will be truncated and all other - removed.
+				 * So attempt to write to some segment cause error because file doesn't exists any more and previous segment is empty or not exists as well.
+				 * Calling `mdnblocks` cause SMGR to open and cache descriptors of all relation segments and so prevent there removal which guarantees that
+				 * subsequent `mdwrite` will succeed.
 				 */
-				return;
+				if (mdnblocks(reln, forknum) >= blkno)
+				{
+					/* prevent race condition with unlogged build end which unlinks local files */
+					mdwritev(reln, forknum, blkno, buffers, nblocks, skipFsync);
+
+					/*
+					 * We could set relpersistence now that we have determined
+					 * that it's local. But we don't dare to do it, because that
+					 * would immediately allow reads as well, which shouldn't
+					 * happen. We could cache it with a different 'relpersistence'
+					 * value, but this isn't performance critical.
+					 */
+					return;
+				}
 			}
 			break;

 		case RELPERSISTENCE_PERMANENT:
+			if (RelFileInfoEquals(unlogged_build_rel_info, InfoFromSMgrRel(reln)))
+			{
+				mdwritev(reln, forknum, blkno, buffers, nblocks, skipFsync);
+				return;
+			}
 			break;

 		case RELPERSISTENCE_TEMP:
@@ -1706,6 +1761,10 @@ neon_nblocks(SMgrRelation reln, ForkNumber forknum)
 			break;

 		case RELPERSISTENCE_PERMANENT:
+			if (RelFileInfoEquals(unlogged_build_rel_info, InfoFromSMgrRel(reln)))
+			{
+				return mdnblocks(reln, forknum);
+			}
 			break;

 		case RELPERSISTENCE_TEMP:
@@ -1775,6 +1834,11 @@ neon_truncate(SMgrRelation reln, ForkNumber forknum, BlockNumber old_blocks, Blo
 			break;

 		case RELPERSISTENCE_PERMANENT:
+			if (RelFileInfoEquals(unlogged_build_rel_info, InfoFromSMgrRel(reln)))
+			{
+				mdtruncate(reln, forknum, old_blocks, nblocks);
+				return;
+			}
 			break;

 		case RELPERSISTENCE_TEMP:
@@ -1913,7 +1977,6 @@ neon_start_unlogged_build(SMgrRelation reln)
 	 */
 	if (unlogged_build_phase != UNLOGGED_BUILD_NOT_IN_PROGRESS)
 		neon_log(ERROR, "unlogged relation build is already in progress");
-	Assert(unlogged_build_rel == NULL);

 	ereport(SmgrTrace,
 			(errmsg(NEON_TAG "starting unlogged build of relation %u/%u/%u",
@@ -1930,7 +1993,7 @@ neon_start_unlogged_build(SMgrRelation reln)

 		case RELPERSISTENCE_TEMP:
 		case RELPERSISTENCE_UNLOGGED:
-			unlogged_build_rel = reln;
+			unlogged_build_rel_info = InfoFromSMgrRel(reln);
 			unlogged_build_phase = UNLOGGED_BUILD_NOT_PERMANENT;
 #ifdef DEBUG_COMPARE_LOCAL
 			if (!IsParallelWorker())
@@ -1951,12 +2014,9 @@ neon_start_unlogged_build(SMgrRelation reln)
 		neon_log(ERROR, "cannot perform unlogged index build, index is not empty ");
 #endif

-	unlogged_build_rel = reln;
+	unlogged_build_rel_info = InfoFromSMgrRel(reln);
 	unlogged_build_phase = UNLOGGED_BUILD_PHASE_1;

-	/* Make the relation look like it's unlogged */
-	reln->smgr_relpersistence = RELPERSISTENCE_UNLOGGED;
-
 	/*
 	 * Create the local file. In a parallel build, the leader is expected to
 	 * call this first and do it.
@@ -1983,17 +2043,16 @@ neon_start_unlogged_build(SMgrRelation reln)
 static void
 neon_finish_unlogged_build_phase_1(SMgrRelation reln)
 {
-	Assert(unlogged_build_rel == reln);
+	Assert(RelFileInfoEquals(unlogged_build_rel_info, InfoFromSMgrRel(reln)));

 	ereport(SmgrTrace,
 			(errmsg(NEON_TAG "finishing phase 1 of unlogged build of relation %u/%u/%u",
-					RelFileInfoFmt(InfoFromSMgrRel(reln)))));
+					RelFileInfoFmt((unlogged_build_rel_info)))));

 	if (unlogged_build_phase == UNLOGGED_BUILD_NOT_PERMANENT)
 		return;

 	Assert(unlogged_build_phase == UNLOGGED_BUILD_PHASE_1);
-	Assert(reln->smgr_relpersistence == RELPERSISTENCE_UNLOGGED);

 	/*
 	 * In a parallel build, (only) the leader process performs the 2nd
@@ -2001,7 +2060,7 @@ neon_finish_unlogged_build_phase_1(SMgrRelation reln)
 	 */
 	if (IsParallelWorker())
 	{
-		unlogged_build_rel = NULL;
+		NRelFileInfoInvalidate(unlogged_build_rel_info);
 		unlogged_build_phase = UNLOGGED_BUILD_NOT_IN_PROGRESS;
 	}
 	else
@@ -2022,11 +2081,11 @@ neon_end_unlogged_build(SMgrRelation reln)
 {
 	NRelFileInfoBackend rinfob = InfoBFromSMgrRel(reln);

-	Assert(unlogged_build_rel == reln);
+	Assert(RelFileInfoEquals(unlogged_build_rel_info, InfoFromSMgrRel(reln)));

 	ereport(SmgrTrace,
 			(errmsg(NEON_TAG "ending unlogged build of relation %u/%u/%u",
-					RelFileInfoFmt(InfoFromNInfoB(rinfob)))));
+					RelFileInfoFmt(unlogged_build_rel_info))));

 	if (unlogged_build_phase != UNLOGGED_BUILD_NOT_PERMANENT)
 	{
@@ -2034,7 +2093,6 @@ neon_end_unlogged_build(SMgrRelation reln)
 		BlockNumber nblocks;

 		Assert(unlogged_build_phase == UNLOGGED_BUILD_PHASE_2);
-		Assert(reln->smgr_relpersistence == RELPERSISTENCE_UNLOGGED);

 		/*
 		 * Update the last-written LSN cache.
@@ -2055,9 +2113,6 @@ neon_end_unlogged_build(SMgrRelation reln)
 								InfoFromNInfoB(rinfob),
 								MAIN_FORKNUM);

-		/* Make the relation look permanent again */
-		reln->smgr_relpersistence = RELPERSISTENCE_PERMANENT;
-
 		/* Remove local copy */
 		for (int forknum = 0; forknum <= MAX_FORKNUM; forknum++)
 		{
@@ -2078,7 +2133,7 @@ neon_end_unlogged_build(SMgrRelation reln)
 		mdunlink(rinfob, INIT_FORKNUM, true);
 #endif
 	}
-	unlogged_build_rel = NULL;
+	NRelFileInfoInvalidate(unlogged_build_rel_info);
 	unlogged_build_phase = UNLOGGED_BUILD_NOT_IN_PROGRESS;
 }

@@ -2151,7 +2206,7 @@ AtEOXact_neon(XactEvent event, void *arg)
 			 * Forget about any build we might have had in progress. The local
 			 * file will be unlinked by smgrDoPendingDeletes()
 			 */
-			unlogged_build_rel = NULL;
+			NRelFileInfoInvalidate(unlogged_build_rel_info);
 			unlogged_build_phase = UNLOGGED_BUILD_NOT_IN_PROGRESS;
 			break;

@@ -2163,7 +2218,7 @@ AtEOXact_neon(XactEvent event, void *arg)
 		case XACT_EVENT_PRE_PREPARE:
 			if (unlogged_build_phase != UNLOGGED_BUILD_NOT_IN_PROGRESS)
 			{
-				unlogged_build_rel = NULL;
+				NRelFileInfoInvalidate(unlogged_build_rel_info);
 				unlogged_build_phase = UNLOGGED_BUILD_NOT_IN_PROGRESS;
 				ereport(ERROR,
 						(errcode(ERRCODE_INTERNAL_ERROR),
--- a/pgxn/neon/walproposer.c
+++ b/pgxn/neon/walproposer.c
@@ -155,8 +155,9 @@ WalProposerCreate(WalProposerConfig *config, walproposer_api api)
 			int			written = 0;

 			written = snprintf((char *) &sk->conninfo, MAXCONNINFO,
-							   "host=%s port=%s dbname=replication options='-c timeline_id=%s tenant_id=%s'",
-							   sk->host, sk->port, wp->config->neon_timeline, wp->config->neon_tenant);
+							   "%s host=%s port=%s dbname=replication options='-c timeline_id=%s tenant_id=%s'",
+							   wp->config->safekeeper_conninfo_options, sk->host, sk->port,
+							   wp->config->neon_timeline, wp->config->neon_tenant);
 			if (written > MAXCONNINFO || written < 0)
 				wp_log(FATAL, "could not create connection string for safekeeper %s:%s", sk->host, sk->port);
 		}
--- a/pgxn/neon/walproposer.h
+++ b/pgxn/neon/walproposer.h
@@ -714,6 +714,9 @@ typedef struct WalProposerConfig
 	 */
 	char	   *safekeepers_list;

+	/* libpq connection info options. */
+	char	   *safekeeper_conninfo_options;
+
 	/*
 	 * WalProposer reconnects to offline safekeepers once in this interval.
 	 * Time is in milliseconds.
--- a/pgxn/neon/walproposer_pg.c
+++ b/pgxn/neon/walproposer_pg.c
@@ -64,6 +64,7 @@ char	   *wal_acceptors_list = "";
 int			wal_acceptor_reconnect_timeout = 1000;
 int			wal_acceptor_connection_timeout = 10000;
 int			safekeeper_proto_version = 3;
+char	   *safekeeper_conninfo_options = "";

 /* Set to true in the walproposer bgw. */
 static bool am_walproposer;
@@ -119,6 +120,7 @@ init_walprop_config(bool syncSafekeepers)
 	walprop_config.neon_timeline = neon_timeline;
 	/* WalProposerCreate scribbles directly on it, so pstrdup */
 	walprop_config.safekeepers_list = pstrdup(wal_acceptors_list);
+	walprop_config.safekeeper_conninfo_options = pstrdup(safekeeper_conninfo_options);
 	walprop_config.safekeeper_reconnect_timeout = wal_acceptor_reconnect_timeout;
 	walprop_config.safekeeper_connection_timeout = wal_acceptor_connection_timeout;
 	walprop_config.wal_segment_size = wal_segment_size;
@@ -203,6 +205,16 @@ nwp_register_gucs(void)
 												 * GUC_LIST_QUOTE */
 							   NULL, assign_neon_safekeepers, NULL);

+	DefineCustomStringVariable(
+							   "neon.safekeeper_conninfo_options",
+							   "libpq keyword parameters and values to apply to safekeeper connections",
+							   NULL,
+							   &safekeeper_conninfo_options,
+							   "",
+							   PGC_POSTMASTER,
+							   0,
+							   NULL, NULL, NULL);
+
 	DefineCustomIntVariable(
 							"neon.safekeeper_reconnect_timeout",
 							"Walproposer reconnects to offline safekeepers once in this interval.",
--- a/poetry.lock
+++ b/poetry.lock
@@ -1,4 +1,4 @@
-# This file is automatically @generated by Poetry 2.1.2 and should not be changed by hand.
+# This file is automatically @generated by Poetry 2.1.1 and should not be changed by hand.

 [[package]]
 name = "aiohappyeyeballs"
@@ -1145,18 +1145,19 @@ dotenv = ["python-dotenv"]

 [[package]]
 name = "flask-cors"
-version = "5.0.0"
-description = "A Flask extension adding a decorator for CORS support"
+version = "6.0.0"
+description = "A Flask extension simplifying CORS support"
 optional = false
-python-versions = "*"
+python-versions = "<4.0,>=3.9"
 groups = ["main"]
 files = [
-    {file = "Flask_Cors-5.0.0-py2.py3-none-any.whl", hash = "sha256:b9e307d082a9261c100d8fb0ba909eec6a228ed1b60a8315fd85f783d61910bc"},
-    {file = "flask_cors-5.0.0.tar.gz", hash = "sha256:5aadb4b950c4e93745034594d9f3ea6591f734bb3662e16e255ffbf5e89c88ef"},
+    {file = "flask_cors-6.0.0-py3-none-any.whl", hash = "sha256:6332073356452343a8ccddbfec7befdc3fdd040141fe776ec9b94c262f058657"},
+    {file = "flask_cors-6.0.0.tar.gz", hash = "sha256:4592c1570246bf7beee96b74bc0adbbfcb1b0318f6ba05c412e8909eceec3393"},
 ]

 [package.dependencies]
-Flask = ">=0.9"
+flask = ">=0.9"
+Werkzeug = ">=0.7"

 [[package]]
 name = "frozenlist"
@@ -3169,19 +3170,24 @@ pbr = "*"

 [[package]]
 name = "setuptools"
-version = "70.0.0"
+version = "78.1.1"
 description = "Easily download, build, install, upgrade, and uninstall Python packages"
 optional = false
-python-versions = ">=3.8"
+python-versions = ">=3.9"
 groups = ["main"]
 files = [
-    {file = "setuptools-70.0.0-py3-none-any.whl", hash = "sha256:54faa7f2e8d2d11bcd2c07bed282eef1046b5c080d1c32add737d7b5817b1ad4"},
-    {file = "setuptools-70.0.0.tar.gz", hash = "sha256:f211a66637b8fa059bb28183da127d4e86396c991a942b028c6650d4319c3fd0"},
+    {file = "setuptools-78.1.1-py3-none-any.whl", hash = "sha256:c3a9c4211ff4c309edb8b8c4f1cbfa7ae324c4ba9f91ff254e3d305b9fd54561"},
+    {file = "setuptools-78.1.1.tar.gz", hash = "sha256:fcc17fd9cd898242f6b4adfaca46137a9edef687f43e6f78469692a5e70d851d"},
 ]

 [package.extras]
-docs = ["furo", "jaraco.packaging (>=9.3)", "jaraco.tidelift (>=1.4)", "pygments-github-lexers (==0.0.5)", "pyproject-hooks (!=1.1)", "rst.linker (>=1.9)", "sphinx (>=3.5)", "sphinx-favicon", "sphinx-inline-tabs", "sphinx-lint", "sphinx-notfound-page (>=1,<2)", "sphinx-reredirects", "sphinxcontrib-towncrier"]
-testing = ["build[virtualenv] (>=1.0.3)", "filelock (>=3.4.0)", "importlib-metadata", "ini2toml[lite] (>=0.14)", "jaraco.develop (>=7.21) ; python_version >= \"3.9\" and sys_platform != \"cygwin\"", "jaraco.envs (>=2.2)", "jaraco.path (>=3.2.0)", "mypy (==1.9)", "packaging (>=23.2)", "pip (>=19.1)", "pyproject-hooks (!=1.1)", "pytest (>=6,!=8.1.1)", "pytest-checkdocs (>=2.4)", "pytest-cov ; platform_python_implementation != \"PyPy\"", "pytest-enabler (>=2.2)", "pytest-home (>=0.5)", "pytest-mypy", "pytest-perf ; sys_platform != \"cygwin\"", "pytest-ruff (>=0.2.1) ; sys_platform != \"cygwin\"", "pytest-subprocess", "pytest-timeout", "pytest-xdist (>=3)", "tomli", "tomli-w (>=1.0.0)", "virtualenv (>=13.0.0)", "wheel"]
+check = ["pytest-checkdocs (>=2.4)", "pytest-ruff (>=0.2.1) ; sys_platform != \"cygwin\"", "ruff (>=0.8.0) ; sys_platform != \"cygwin\""]
+core = ["importlib_metadata (>=6) ; python_version < \"3.10\"", "jaraco.functools (>=4)", "jaraco.text (>=3.7)", "more_itertools", "more_itertools (>=8.8)", "packaging (>=24.2)", "platformdirs (>=4.2.2)", "tomli (>=2.0.1) ; python_version < \"3.11\"", "wheel (>=0.43.0)"]
+cover = ["pytest-cov"]
+doc = ["furo", "jaraco.packaging (>=9.3)", "jaraco.tidelift (>=1.4)", "pygments-github-lexers (==0.0.5)", "pyproject-hooks (!=1.1)", "rst.linker (>=1.9)", "sphinx (>=3.5)", "sphinx-favicon", "sphinx-inline-tabs", "sphinx-lint", "sphinx-notfound-page (>=1,<2)", "sphinx-reredirects", "sphinxcontrib-towncrier", "towncrier (<24.7)"]
+enabler = ["pytest-enabler (>=2.2)"]
+test = ["build[virtualenv] (>=1.0.3)", "filelock (>=3.4.0)", "ini2toml[lite] (>=0.14)", "jaraco.develop (>=7.21) ; python_version >= \"3.9\" and sys_platform != \"cygwin\"", "jaraco.envs (>=2.2)", "jaraco.path (>=3.7.2)", "jaraco.test (>=5.5)", "packaging (>=24.2)", "pip (>=19.1)", "pyproject-hooks (!=1.1)", "pytest (>=6,!=8.1.*)", "pytest-home (>=0.5)", "pytest-perf ; sys_platform != \"cygwin\"", "pytest-subprocess", "pytest-timeout", "pytest-xdist (>=3)", "tomli-w (>=1.0.0)", "virtualenv (>=13.0.0)", "wheel (>=0.44.0)"]
+type = ["importlib_metadata (>=7.0.2) ; python_version < \"3.10\"", "jaraco.develop (>=7.21) ; sys_platform != \"cygwin\"", "mypy (==1.14.*)", "pytest-mypy"]

 [[package]]
 name = "six"
--- a/proxy/Cargo.toml
+++ b/proxy/Cargo.toml
@@ -73,7 +73,6 @@ rustc-hash.workspace = true
 rustls.workspace = true
 rustls-native-certs.workspace = true
 rustls-pemfile.workspace = true
-ryu = "1"
 scopeguard.workspace = true
 serde.workspace = true
 serde_json.workspace = true
@@ -128,3 +127,4 @@ rstest.workspace = true
 walkdir.workspace = true
 rand_distr = "0.4"
 tokio-postgres.workspace = true
+tracing-test = "0.2"
--- a/proxy/src/auth/backend/mod.rs
+++ b/proxy/src/auth/backend/mod.rs
@@ -80,10 +80,22 @@ impl std::fmt::Display for Backend<'_, ()> {
                    .field(&endpoint.url())
                    .finish(),
                #[cfg(any(test, feature = "testing"))]
-                ControlPlaneClient::PostgresMock(endpoint) => fmt
-                    .debug_tuple("ControlPlane::PostgresMock")
-                    .field(&endpoint.url())
-                    .finish(),
+                ControlPlaneClient::PostgresMock(endpoint) => {
+                    let url = endpoint.url();
+                    match url::Url::parse(url) {
+                        Ok(mut url) => {
+                            let _ = url.set_password(Some("_redacted_"));
+                            let url = url.as_str();
+                            fmt.debug_tuple("ControlPlane::PostgresMock")
+                                .field(&url)
+                                .finish()
+                        }
+                        Err(_) => fmt
+                            .debug_tuple("ControlPlane::PostgresMock")
+                            .field(&url)
+                            .finish(),
+                    }
+                }
                #[cfg(test)]
                ControlPlaneClient::Test(_) => fmt.debug_tuple("ControlPlane::Test").finish(),
            },
--- a/proxy/src/binary/proxy.rs
+++ b/proxy/src/binary/proxy.rs
@@ -1,9 +1,13 @@
+#[cfg(any(test, feature = "testing"))]
+use std::env;
 use std::net::SocketAddr;
 use std::path::PathBuf;
 use std::pin::pin;
 use std::sync::Arc;
 use std::time::Duration;

+#[cfg(any(test, feature = "testing"))]
+use anyhow::Context;
 use anyhow::{bail, ensure};
 use arc_swap::ArcSwapOption;
 use futures::future::Either;
@@ -35,6 +39,8 @@ use crate::scram::threadpool::ThreadPool;
 use crate::serverless::GlobalConnPoolOptions;
 use crate::serverless::cancel_set::CancelSet;
 use crate::tls::client_config::compute_client_config_with_root_certs;
+#[cfg(any(test, feature = "testing"))]
+use crate::url::ApiUrl;
 use crate::{auth, control_plane, http, serverless, usage_metrics};

 project_git_version!(GIT_VERSION);
@@ -161,8 +167,11 @@ struct ProxyCliArgs {
    #[clap(long, default_values_t = RateBucketInfo::DEFAULT_REDIS_SET)]
    redis_rps_limit: Vec<RateBucketInfo>,
    /// Cancellation channel size (max queue size for redis kv client)
-    #[clap(long, default_value = "1024")]
+    #[clap(long, default_value_t = 1024)]
    cancellation_ch_size: usize,
+    /// Cancellation ops batch size for redis
+    #[clap(long, default_value_t = 8)]
+    cancellation_batch_size: usize,
    /// cache for `allowed_ips` (use `size=0` to disable)
    #[clap(long, default_value = config::CacheOptions::CACHE_DEFAULT_OPTIONS)]
    allowed_ips_cache: String,
@@ -542,7 +551,12 @@ pub async fn run() -> anyhow::Result<()> {
            if let Some(mut redis_kv_client) = redis_kv_client {
                maintenance_tasks.spawn(async move {
                    redis_kv_client.try_connect().await?;
-                    handle_cancel_messages(&mut redis_kv_client, rx_cancel).await?;
+                    handle_cancel_messages(
+                        &mut redis_kv_client,
+                        rx_cancel,
+                        args.cancellation_batch_size,
+                    )
+                    .await?;

                    drop(redis_kv_client);

@@ -769,7 +783,13 @@ fn build_auth_backend(

        #[cfg(any(test, feature = "testing"))]
        AuthBackendType::Postgres => {
-            let url = args.auth_endpoint.parse()?;
+            let mut url: ApiUrl = args.auth_endpoint.parse()?;
+            if url.password().is_none() {
+                let password = env::var("PGPASSWORD")
+                    .with_context(|| "auth-endpoint does not contain a password and environment variable `PGPASSWORD` is not set")?;
+                url.set_password(Some(&password))
+                    .expect("Failed to set password");
+            }
            let api = control_plane::client::mock::MockControlPlane::new(
                url,
                !args.is_private_access_proxy,
--- a/proxy/src/cancellation.rs
+++ b/proxy/src/cancellation.rs
@@ -30,8 +30,6 @@ use crate::tls::postgres_rustls::MakeRustlsConnect;
 type IpSubnetKey = IpNet;

 const CANCEL_KEY_TTL: i64 = 1_209_600; // 2 weeks cancellation key expire time
-const REDIS_SEND_TIMEOUT: std::time::Duration = std::time::Duration::from_millis(10);
-const BATCH_SIZE: usize = 8;

 // Message types for sending through mpsc channel
 pub enum CancelKeyOp {
@@ -231,12 +229,13 @@ impl CancelReplyOp {
 pub async fn handle_cancel_messages(
    client: &mut RedisKVClient,
    mut rx: mpsc::Receiver<CancelKeyOp>,
+    batch_size: usize,
 ) -> anyhow::Result<()> {
-    let mut batch = Vec::with_capacity(BATCH_SIZE);
-    let mut pipeline = Pipeline::with_capacity(BATCH_SIZE);
+    let mut batch = Vec::with_capacity(batch_size);
+    let mut pipeline = Pipeline::with_capacity(batch_size);

    loop {
-        if rx.recv_many(&mut batch, BATCH_SIZE).await == 0 {
+        if rx.recv_many(&mut batch, batch_size).await == 0 {
            warn!("shutting down cancellation queue");
            break Ok(());
        }
@@ -367,8 +366,7 @@ impl CancellationHandler {
            return Err(CancelError::InternalError);
        };

-        tx.send_timeout(op, REDIS_SEND_TIMEOUT)
-            .await
+        tx.try_send(op)
            .map_err(|e| {
                tracing::warn!("failed to send GetCancelData for {key}: {e}");
            })
@@ -570,7 +568,7 @@ impl Session {
    }

    // Send the store key op to the cancellation handler and set TTL for the key
-    pub(crate) async fn write_cancel_key(
+    pub(crate) fn write_cancel_key(
        &self,
        cancel_closure: CancelClosure,
    ) -> Result<(), CancelError> {
@@ -596,14 +594,14 @@ impl Session {
            expire: CANCEL_KEY_TTL,
        };

-        let _ = tx.send_timeout(op, REDIS_SEND_TIMEOUT).await.map_err(|e| {
+        let _ = tx.try_send(op).map_err(|e| {
            let key = self.key;
            tracing::warn!("failed to send StoreCancelKey for {key}: {e}");
        });
        Ok(())
    }

-    pub(crate) async fn remove_cancel_key(&self) -> Result<(), CancelError> {
+    pub(crate) fn remove_cancel_key(&self) -> Result<(), CancelError> {
        let Some(tx) = &self.cancellation_handler.tx else {
            tracing::warn!("cancellation handler is not available");
            return Err(CancelError::InternalError);
@@ -619,7 +617,7 @@ impl Session {
                .guard(RedisMsgKind::HDel),
        };

-        let _ = tx.send_timeout(op, REDIS_SEND_TIMEOUT).await.map_err(|e| {
+        let _ = tx.try_send(op).map_err(|e| {
            let key = self.key;
            tracing::warn!("failed to send RemoveCancelKey for {key}: {e}");
        });
--- a/proxy/src/console_redirect_proxy.rs
+++ b/proxy/src/console_redirect_proxy.rs
@@ -244,9 +244,7 @@ pub(crate) async fn handle_client<S: AsyncRead + AsyncWrite + Unpin>(
    let cancellation_handler_clone = Arc::clone(&cancellation_handler);
    let session = cancellation_handler_clone.get_key();

-    session
-        .write_cancel_key(node.cancel_closure.clone())
-        .await?;
+    session.write_cancel_key(node.cancel_closure.clone())?;

    prepare_client_connection(&node, *session.key(), &mut stream).await?;

--- a/proxy/src/logging/mod.rs
+++ b/proxy/src/logging/mod.rs
--- a/Show More
+++ b/Show More