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Merge pull request #12680 from bboreham/faster-has

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labels: improve Has() method for stringlabels build
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Bryan Boreham 2023-08-14 15:47:47 +01:00 committed by GitHub
parent d7293ea8b5 b5c6807fea
commit 5007fa305d
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GPG key ID: 4AEE18F83AFDEB23
2 changed files with 32 additions and 13 deletions
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19
model/labels/labels_stringlabels.go
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@ -300,13 +300,26 @@ func (ls Labels) Get(name string) string {
// Has returns true if the label with the given name is present. // Has returns true if the label with the given name is present.
func (ls Labels) Has(name string) bool { func (ls Labels) Has(name string) bool {
if name == "" { // Avoid crash in loop if someone asks for "".
return false // Prometheus does not store blank label names.
}
for i := 0; i < len(ls.data); { for i := 0; i < len(ls.data); {
var lName string var size int
lName, i = decodeString(ls.data, i) size, i = decodeSize(ls.data, i)
_, i = decodeString(ls.data, i) if ls.data[i] == name[0] {
lName := ls.data[i : i+size]
i += size
if lName == name { if lName == name {
return true return true
} }
} else {
if ls.data[i] > name[0] { // Stop looking if we've gone past.
break
}
i += size
}
size, i = decodeSize(ls.data, i)
i += size
} }
return false return false
} }

16
model/labels/labels_test.go
View file

@ -472,17 +472,23 @@ func BenchmarkLabels_Get(b *testing.B) {
for _, scenario := range []struct { for _, scenario := range []struct {
desc, label string desc, label string
}{ }{
{"get first label", allLabels[0].Name}, {"first label", allLabels[0].Name},
{"get middle label", allLabels[size/2].Name}, {"middle label", allLabels[size/2].Name},
{"get last label", allLabels[size-1].Name}, {"last label", allLabels[size-1].Name},
{"get not-found label", "benchmark"}, {"not-found label", "benchmark"},
} { } {
b.Run(scenario.desc, func(b *testing.B) { b.Run(scenario.desc, func(b *testing.B) {
b.ResetTimer() b.Run("get", func(b *testing.B) {
for i := 0; i < b.N; i++ { for i := 0; i < b.N; i++ {
_ = labels.Get(scenario.label) _ = labels.Get(scenario.label)
} }
}) })
b.Run("has", func(b *testing.B) {
for i := 0; i < b.N; i++ {
_ = labels.Has(scenario.label)
}
})
})
} }
}) })
} }