Make full microbenchmark execution local-only

.github/workflows/extended.yml

@@ -92,28 +92,6 @@ jobs:
           - name: Cleanup
             run: cargo clean
 
-  # Execute Criterion benchmarks once to catch panics without measuring performance.
-  linux-test-microbenchmarks:
-    name: microbenchmark tests (amd64)
-    # Long-running job: run in the merge queue, on release pushes, or manually.
-    if: github.event_name != 'pull_request'
-    runs-on: ${{ vars.USE_RUNS_ON == 'true' && format('runs-on={0},family=m8a+m7a+c8a,cpu=16,image=ubuntu24-full-x64,extras=s3-cache,disk=large,tag=datafusion', github.run_id) || 'ubuntu-latest' }}
-    container:
-      image: amd64/rust
-    steps:
-      - uses: runs-on/action@17b59092eb37ebfdbb034460892887c09100eaa3  # v2.5.0
-      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7.0.1
-        with:
-          ref: ${{ github.event.inputs.pr_head_sha }} # otherwise use the event's commit, including the merge group
-          submodules: true
-          fetch-depth: 1
-      - name: Setup Rust toolchain
-        uses: ./.github/actions/setup-builder
-        with:
-          rust-version: stable
-      - name: Test microbenchmarks
-        run: cargo xtask ci step test microbenchmarks
-
   # Check answers are correct when hash values collide
   hash-collisions:
     name: cargo test hash collisions (amd64)

docs/source/contributor-guide/testing.md

@@ -411,6 +411,19 @@ A full list of benchmarks can be found [here](https://github.com/apache/datafusi
 
 _[cargo-criterion](https://github.com/bheisler/cargo-criterion) may also be used for more advanced reporting._
 
+### Microbenchmark health checks (local-only)
+
+Runs each microbenchmark case once to catch runtime panics, without measuring performance:
+
+```shell
+cargo xtask ci step test microbenchmarks
+```
+
+The suite took about 10 minutes in CI, so execution is local-only, including on
+release branches; no hosted workflow or required check is provided. Runtime failures
+may go unnoticed until a local run. When changing benchmark fixtures, setup, or APIs,
+run the affected benchmarks and include the commands and results in your PR.
+
 ### Parquet SQL Benchmarks
 
 The parquet SQL benchmarks can be run with