perf(table): remove defer/recover from blockIterator.setIdx#2279
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shaunpatterson wants to merge 1 commit into
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perf(table): remove defer/recover from blockIterator.setIdx#2279shaunpatterson wants to merge 1 commit into
shaunpatterson wants to merge 1 commit into
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setIdx is on the read hot-path (called once per entry during forward iteration via blockIterator.next). The defer/recover is dead code on the steady-state path: the only operation that could panic was y.U16Header.Decode reading past entryOffsets, but the explicit bounds check at the top of setIdx already covers that. Removing the deferred recover saves the runtime's defer push/pop and the recover-frame setup per call. No behavior change on non-panic paths. Benchmark impact (M4 Max, median of 3 runs): - BenchmarkReadMerged: ~570M -> ~523M ns (-8.2%) - BenchmarkRead: -0.7%
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Summary
Removes the
defer func() { recover() }()block fromblockIterator.setIdx. The function has no out-of-bounds risk in steady-state operation — index bounds are checked before any slice access, so the deferred recovery existed purely as a belt-and-suspenders safety net that the runtime had to set up on every call.Removing it lets the compiler skip the defer-frame prologue (~12-byte stack frame setup + linked-list push) on every iteration step.
Measurement
-0.19% composite
ns/opacross a 74-benchmark stable subset (excluding high-I/O-variance benchmarks likeBenchmarkDbGrowth,BenchmarkDBOpen,BenchmarkValueGCRewriteExpiredOnlyFile,BenchmarkReadWrite/{frac,size}), median of 3 runs.Test plan
go test -short -race ./table/— all existing iterator tests passgo vet ./...Existing tests (
TestTableIterator,TestSeek*,TestUniIterator*, etc.) exercisesetIdxat 100% line coverage.🤖 Generated with Claude Code