shard: skip hashmapStats allocation when stats are disabled#423
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c-tonneslan wants to merge 1 commit into
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shard: skip hashmapStats allocation when stats are disabled#423c-tonneslan wants to merge 1 commit into
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initNewShard always built a hashmapStats map even when StatsEnabled was false. allegro#420 cut the capacity hint to 0 for that case, but make still returned a real empty map per shard, so the default Config still paid for an unused map header on every shard. All hashmapStats writes (hit, hitWithoutLock, del) are already guarded by s.statsEnabled, and the reads in getKeyMetadata{,WithLock} return the zero value of uint32 for a nil map, which is what they'd return for a missing key anyway. Leaving hashmapStats nil when stats are off is behaviour-preserving. Closes allegro#422 Signed-off-by: Charlie Tonneslan <cst0520@gmail.com>
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`initNewShard` always built a `hashmapStats` map even when `StatsEnabled` was false. #420 dropped the capacity hint to 0 for that case, but `make` still returns a real empty map per shard, so the default `Config` still pays for an unused map header on every shard.
All `hashmapStats` writes (`hit`, `hitWithoutLock`, `del`) are already guarded by `s.statsEnabled`, and the reads in `getKeyMetadata{,WithLock}` return the zero value of `uint32` for a nil map, which is what they'd return for a missing key anyway. Leaving `hashmapStats` nil when stats are off is behaviour-preserving. `go test ./...` passes.
fixes #422