docs(design): close ABW-3 as N/A pending per-file Mutex refactor#4685
Merged
Conversation
The ABW-3 implementation (pipelined verify/write overlap on apply_batch_parallel) cannot ship a meaningful throughput improvement while the per-file Mutex<FileSlot> in ParallelDeltaApplier serialises the write critical section. The closure note formalises that structural blocker as the re-open precondition, in addition to the BR-3j.f bench-evidence gate inherited from the sibling ABW-2 closure. ABW-4 (bench) is also N/A since there is nothing to measure until ABW-3 has a real artifact.
github-actions
Bot
added
the
documentation
5 tasks
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Summary
docs/design/abw-3-closure-2026-05-21.md, a closure note for the ABW-3 implementation track.apply_batch_parallel) as N/A pending per-file Mutex refactor inParallelDeltaApplier, with ABW-4 (bench) inheriting the same status because there is nothing to measure.Mutex<FileSlot>refactor as a re-open precondition in addition to the BR-3j.f bench-evidence gate inherited from the siblingabw-2-pipelined-verify-write-deferred-2026-05-21.md. Cross-referencesproject_apply_batch_write_serial.mdandproject_parallel_delta_apply_outer_mutex.md, which keep tracking the larger refactor initiative.Docs-only. No source changes. No design surface beyond the closure note.
Test plan
cargo fmt --allclean (docs-only change; no formattable edits).