mudhorn/prometheus
1
0
Fork 0
mirror of https://github.com/prometheus/prometheus.git synced 2025-03-05 20:59:13 -08:00
Code Issues Actions 4 Packages Projects Releases Wiki Activity

[PERF] TSDB: Grow postings by doubling

Browse source 
Go's built-in append() grows larger slices with factor 1.3, which means we do a lot more allocating and copying for larger postings.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
This commit is contained in:
Bryan Boreham 2024-08-23 09:30:22 +01:00
parent 1435c8ae4a
commit 33adbe47b1
1 changed files with 10 additions and 1 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

11
tsdb/index/postings.go
View file

@ -345,13 +345,22 @@ func (p *MemPostings) Add(id storage.SeriesRef, lset labels.Labels) {
p.mtx.Unlock() p.mtx.Unlock()
} }
func appendWithExponentialGrowth[T any](a []T, v T) []T {
if cap(a) < len(a)+1 {
newList := make([]T, len(a), len(a)*2+1)
copy(newList, a)
a = newList
}
return append(a, v)
}
func (p *MemPostings) addFor(id storage.SeriesRef, l labels.Label) { func (p *MemPostings) addFor(id storage.SeriesRef, l labels.Label) {
nm, ok := p.m[l.Name] nm, ok := p.m[l.Name]
if !ok { if !ok {
nm = map[string][]storage.SeriesRef{} nm = map[string][]storage.SeriesRef{}
p.m[l.Name] = nm p.m[l.Name] = nm
} }
list := append(nm[l.Value], id) list := appendWithExponentialGrowth(nm[l.Value], id)
nm[l.Value] = list nm[l.Value] = list
if !p.ordered { if !p.ordered {