perf(posting): avoid redundant proto.Clone in setMutationAfterCommit#9717
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shaunpatterson wants to merge 1 commit into
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perf(posting): avoid redundant proto.Clone in setMutationAfterCommit#9717shaunpatterson wants to merge 1 commit into
shaunpatterson wants to merge 1 commit into
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When rebuilding committedEntries, copy the *pb.PostingList values by reference instead of proto.Clone. Per MutableLayer's documented invariant, committed entries are immutable once inserted and MutableLayer.clone() already shares the map by reference, so the deep clone was redundant. Only the map itself must be freshly allocated. BenchmarkSetMutationAfterCommit (priorEntries 1..256): sec/op 825µs -> 174µs (-78.9%, p=0.002) B/op 1.65Mi -> 304Ki (-82.0%, p=0.002) allocs/op 15.26k -> 40 (-99.74%, p=0.002)
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When rebuilding
committedEntries, copy the*pb.PostingListvalues by reference instead ofproto.Clone. PerMutableLayer's documented invariant, committed entries are immutable once inserted andMutableLayer.clone()already shares the map by reference, so the deep clone was redundant. Only the map itself must be freshly allocated.BenchmarkSetMutationAfterCommit: sec/op -79%, B/op -82%, allocs/op 15.26k→40 (-99.7%). Full posting unit suite passes.Independent change; branched from
4b9b399d(no dependency on the other PRs in this set). Verified: package unit tests pass + Go benchmark (benchstat, p<0.01). Numbers are single-thread microbenchmarks; not yet run through the Docker integration suite.