benchmarks.yml

# Write-path regression gate — §2.4 of docs/performance/INSERT_UPDATE_PERFORMANCE_PLAN.md.
#
# The plan asks for the benchmark to be runnable as a non-gating (nightly/manual) job, "so future work
# cannot silently regress INSERT/UPDATE the way UPDATE did between 2.0 and 2.1". The need is not
# theoretical: during the v2.1 deferred-DELETE work, a reconcile placed at Table.Flush() made random-key
# DELETE 4x slower (294,185 -> 70,248 ops/sec) and every one of the 2,321 tests stayed green — only a
# hand-run of the harness caught it.
#
# This workflow never blocks a pull request: it is its own workflow, so no branch-protection rule
# requires it. It exists to make a regression visible, not to fail a merge.
#
# What it compares against:
#   tests/benchmarks/SharpCoreDB.Benchmarks.Comparative/baselines/dual-mode-baseline.json
# That baseline was recorded on the maintainer's machine. GitHub-hosted runners get a different CPU on
# every run, so on this runner the comparison is TREND evidence only. Run the same command on a stable
# self-hosted runner (or the dev box) when the answer has to mean something; re-record with
# `--write-baseline` after an intentional change in performance.
#
# Exit codes from the gate: 0 = within tolerance, 1 = a metric regressed beyond the factor,
# 2 = the run was too noisy to conclude anything (the reps disagreed by more than the spread limit).

name: Benchmarks (non-gating)

on:
  workflow_dispatch:
    inputs:
      factor:
        description: 'Regression tolerance — current must be within baseline/factor'
        required: false
        default: '1.5'
  schedule:
    # 03:17 UTC nightly. Off the hour so it does not queue behind the every-hour jobs.
    - cron: '17 3 * * *'

permissions:
  contents: read

env:
  DOTNET_SKIP_FIRST_TIME_EXPERIENCE: true
  DOTNET_CLI_TELEMETRY_OPTOUT: true
  DOTNET_NOLOGO: true
  BENCH_PROJECT: tests/benchmarks/SharpCoreDB.Benchmarks.Comparative/SharpCoreDB.Benchmarks.Comparative.csproj

jobs:
  regression-gate:
    name: Write-path regression gate (§2.4)
    runs-on: ubuntu-latest
    timeout-minutes: 30

    steps:
    - name: Checkout
      uses: actions/checkout@v7
      with:
        fetch-depth: 0

    # The branch's global.json pins the .NET 11 RC SDK (net11.0 + C# 15 preview only).
    - name: Setup .NET 11 (RC)
      uses: actions/setup-dotnet@v6
      with:
        dotnet-version: '11.0.100-rc.1.26425.128'
        include-prerelease: true

    - name: Build the comparative benchmark (Release)
      run: dotnet build "$BENCH_PROJECT" --configuration Release --framework net11.0

    # pipefail + tee: the step goes red when the gate exits non-zero, and the log survives for upload.
    - name: Run the gate
      run: |
        set -o pipefail
        dotnet run --project "$BENCH_PROJECT" \
          --configuration Release --framework net11.0 \
          -- --gate "--gate-factor=${{ github.event.inputs.factor || '1.5' }}" \
          | tee gate-output.txt

    - name: Upload the run log
      if: always()
      uses: actions/upload-artifact@v4
      with:
        name: regression-gate-log
        path: gate-output.txt
        retention-days: 14