Ranjan Banerjee 4b44c2b4ba Fix WBM worker retirement and flush test accounting (#15373) ...

Summary:
Pull Request resolved: https://github.com/facebook/rocksdb/pull/15373

Fix worker retirement when changing `WriteBufferManager` from `kFlushLargestAcrossDBs` to `kFlushOldest`. The coordinator could pass its active-policy check, consume the policy-change notification during refresh, and enter a one-second idle wait. This delayed retirement beyond the 300 ms deadline in `WriteBufferManagerTest.FlushPolicyRetiresAndRestartsHandoffWorkers`. Recheck the policy under `sorter_wait_mu` before waiting so the coordinator promptly enters the retirement path. The setter remains non-blocking, and retirement still waits for executor callbacks to finish.

Also fix startup pressure-wait accounting in `BackgroundFlushCycleTest.FastRejectedCandidateDoesNotAddPressureDelay`. Registering the healthy candidate can invalidate the coordinator's initial ranking snapshot and cause a legitimate pressure wait before either handoff runs. The old assertion counted waits from startup and incorrectly attributed that wait to the rejected candidate. Record the counts at rejected and healthy dispatch and require them to match, preserving the check that rejection adds no pressure interval.

Include both fixes in this diff so its `write_buffer_manager_test` target covers both corrected behaviors. Replace worker retirement and restart polling with sync-point synchronization. The rejection test deterministically invalidates the first snapshot during healthy-candidate registration, verifies that a startup wait occurred, and checks that advancing to the healthy candidate adds no further pressure wait. Retain the clang-format 21 line wrapping required by CI.

Reviewed By: pdillinger

Differential Revision: D124377137

fbshipit-source-id: 1420196e47ccba0268d0427c4ed623925aa3ad5b

2026-10-09 16:50:24 -07:00

47 KiB

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