feat: increase Drain tree depth from 4 to 30 (#24)

STRRL · web-flow · commit 7cebba5b15fa · 2026-03-10T22:34:58.000-07:00
Matches Loki's default. Higher depth means the prefix tree routes more
precisely, reducing the number of candidate clusters that need similarity
comparison at leaf nodes. This improves both accuracy and performance for
pattern detection.
diff --git a/pkg/pattern/drain.go b/pkg/pattern/drain.go
@@ -23,7 +23,7 @@ type DrainParser struct {
 // NewDrainParser creates a DrainParser with default Drain parameters.
 func NewDrainParser() (*DrainParser, error) {
 	d, err := drain3.NewDrain(
-		drain3.WithDepth(4),
+		drain3.WithDepth(30),
 		drain3.WithSimTh(0.4),
 		drain3.WithExtraDelimiter([]string{"|", "=", ","}),
 	)

Original file line number	Diff line number	Diff line change
`@@ -23,7 +23,7 @@ type DrainParser struct {`
`23`	`23`	`// NewDrainParser creates a DrainParser with default Drain parameters.`
`24`	`24`	`func NewDrainParser() (*DrainParser, error) {`
`25`	`25`	`d, err := drain3.NewDrain(`
`26`		`- drain3.WithDepth(4),`
	`26`	`+ drain3.WithDepth(30),`
`27`	`27`	`drain3.WithSimTh(0.4),`
`28`	`28`	`drain3.WithExtraDelimiter([]string{"\|", "=", ","}),`
`29`	`29`	`)`