fix: complete DS_UNSAFE_FAST_FSYNC rename; drop concluded contention-investigation doc#4690
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balegas wants to merge 3 commits into
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fix: complete DS_UNSAFE_FAST_FSYNC rename; drop concluded contention-investigation doc#4690balegas wants to merge 3 commits into
balegas wants to merge 3 commits into
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The rename in #4675 missed segment.rs's copy of fast_fsync_enabled() — the fsync that actually gates WAL append acks — so the documented DS_UNSAFE_FAST_FSYNC name only affected store/checkpoint fsyncs. Verified with the bench-latency harness: WAL acks now drop ~3.2ms -> ~0.3ms under the new name on macOS. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Investigation is concluded (fixes landed in #4675); drop the tracking doc and its dangling cross-reference in CARDINALITY_1M.md. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
balegas
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samwillis
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Jul 6, 2026
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Summary
Two follow-ups to #4675:
1. Complete the
DS_BENCH_FAST_FSYNC→DS_UNSAFE_FAST_FSYNCrename. The rename in #4675 missedsrc/wal/segment.rs, which has its own copy offast_fsync_enabled()— and that one gates the WAL group-commit fsync, i.e. the fsync that actually determines append-ack latency. As merged, the documentedDS_UNSAFE_FAST_FSYNCname only affected the store/checkpoint fsyncs, so setting it would not speed up WAL-mode acks as the README describes. Includes a changeset.2. Remove the WAL contention investigation tracking doc. The investigation is concluded (fixes landed in #4675); drops
CONTENTION_INVESTIGATION.mdand its dangling cross-reference inCARDINALITY_1M.md.Verification
Re-ran the
bench-latencyharness on macOS against this branch: withDS_UNSAFE_FAST_FSYNC=1, WAL write acks drop from ~3.2 ms (F_FULLFSYNC) to ~0.3 ms, matching the documented behavior.grep -rn DS_BENCH_FAST_FSYNCover the repo is clean, as isCONTENTION_INVESTIGATION.🤖 Generated with Claude Code
https://claude.ai/code/session_0196ak7AuMa8we6DXbzv4zUE