Create rewriting map with maximum capacity

inkel · inkel · commit e79cbc355eb1 · 2025-03-21T11:19:23.000-03:00
By doing this we avoid having to regrow the map, which improves CPU
and memory consumption.
diff --git a/pkg/phlaredb/symdb/dedup_slice.go b/pkg/phlaredb/symdb/dedup_slice.go
@@ -254,7 +254,7 @@ func (s *deduplicatingSlice[M, K, H]) Size() uint64 {
 
 func (s *deduplicatingSlice[M, K, H]) ingest(elems []M, rewriter *rewriter) {
 	var (
-		rewritingMap = make(map[int64]int64)
+		rewritingMap = make(map[int64]int64, len(elems))
 		missing      = int64SlicePool.Get()
 	)
 	missing = missing[:0]

Original file line number	Diff line number	Diff line change
`@@ -254,7 +254,7 @@ func (s *deduplicatingSlice[M, K, H]) Size() uint64 {`
`254`	`254`
`255`	`255`	`func (s deduplicatingSlice[M, K, H]) ingest(elems []M, rewriter rewriter) {`
`256`	`256`	`var (`
`257`		`- rewritingMap = make(map[int64]int64)`
	`257`	`+ rewritingMap = make(map[int64]int64, len(elems))`
`258`	`258`	`missing = int64SlicePool.Get()`
`259`	`259`	`)`
`260`	`260`	`missing = missing[:0]`