perf(decode): replace goroutine-per-type value pool with sync.Pool#53
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perf(decode): replace goroutine-per-type value pool with sync.Pool#53
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Replaces the cachedValues mechanism (unbounded goroutine per type + channel with buffer of 256) with sync.Pool per type stored in a sync.Map. Eliminates goroutine leak — the old approach spawned a goroutine for every unique decoded type that ran forever in an infinite loop. No performance regression in benchmarks.
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Summary
cachedValues(unbounded goroutine per type + channel buffer of 256) withsync.Poolper type stored insync.Mapfor { ch <- reflect.New(t) }loop foreverDetails
The old mechanism used
sync.RWMutex+map[reflect.Type]chan reflect.Valuewith a goroutine per type that pre-generated values into a buffered channel. This leaked goroutines (one per unique type, never cleaned up) and used channel synchronization on the hot path.The new approach uses
sync.Map+sync.Poolper type. Since decoded values are mutated by the caller and not returned to the pool,sync.Pooldegrades topool.New()after GC — but this is equivalent toreflect.New(t)which is what the non-preallocate path already does.Test plan
go test -short -race)