Convert string to bytes once only when doing string filtering. (#1405)

This makes it slightly faster: name old time/op new time/op delta ContainsFilter-4 18.2ns ± 2% 9.8ns ± 1% -46.20% (p=0.000 n=10+8) name old alloc/op new alloc/op delta ContainsFilter-4 0.00B 0.00B ~ (all equal) name old allocs/op new allocs/op delta ContainsFilter-4 0.00 0.00 ~ (all equal) Signed-off-by: Peter Štibraný <peter.stibrany@grafana.com>
grafana · Dec 12, 2019 · 7bb77ec · 7bb77ec
1 parent 7b834c5
commit 7bb77ec
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Showing 2 changed files with 26 additions and 2 deletions.
diff --git a/pkg/logql/ast.go b/pkg/logql/ast.go
@@ -138,13 +138,15 @@ func (e *filterExpr) Filter() (Filter, error) {
 		}
 
 	case labels.MatchEqual:
+		mb := []byte(e.match)
 		f = func(line []byte) bool {
-			return bytes.Contains(line, []byte(e.match))
+			return bytes.Contains(line, mb)
 		}
 
 	case labels.MatchNotEqual:
+		mb := []byte(e.match)
 		f = func(line []byte) bool {
-			return !bytes.Contains(line, []byte(e.match))
+			return !bytes.Contains(line, mb)
 		}
 
 	default:

diff --git a/pkg/logql/ast_test.go b/pkg/logql/ast_test.go
@@ -111,3 +111,25 @@ func Test_FilterMatcher(t *testing.T) {
 		})
 	}
 }
+
+func BenchmarkContainsFilter(b *testing.B) {
+	expr, err := ParseLogSelector(`{app="foo"} |= "foo"`)
+	if err != nil {
+		b.Fatal(err)
+	}
+
+	f, err := expr.Filter()
+	if err != nil {
+		b.Fatal(err)
+	}
+
+	line := []byte("hello world foo bar")
+
+	b.ResetTimer()
+
+	for i := 0; i < b.N; i++ {
+		if !f(line) {
+			b.Fatal("doesn't match")
+		}
+	}
+}