app/vmselect/promql: add missing label filters to binary operands before query execution

This implements the optimization described at https://utcc.utoronto.ca/~cks/space/blog/sysadmin/PrometheusLabelNonOptimization

See also https://github.com/cortexproject/cortex/issues/3253

app/vmselect/promql/exec.go

@@ -175,6 +175,7 @@ func parsePromQLWithCache(q string) (metricsql.Expr, error) {
 	if pcv == nil {
 		e, err := metricsql.Parse(q)
 		if err == nil {
+			e = metricsql.Optimize(e)
 			e = adjustCmpOps(e)
 		}
 		pcv = &parseCacheValue{

go.mod

@@ -9,7 +9,7 @@ require (
 	// like https://github.com/valyala/fasthttp/commit/996610f021ff45fdc98c2ce7884d5fa4e7f9199b
 	github.com/VictoriaMetrics/fasthttp v1.0.7
 	github.com/VictoriaMetrics/metrics v1.12.3
-	github.com/VictoriaMetrics/metricsql v0.6.0
+	github.com/VictoriaMetrics/metricsql v0.7.0
 	github.com/aws/aws-sdk-go v1.35.3
 	github.com/cespare/xxhash/v2 v2.1.1
 	github.com/golang/snappy v0.0.2

go.sum

@@ -61,8 +61,8 @@ github.com/VictoriaMetrics/metrics v1.12.2 h1:SG8iAmqavDNuh7GIdHPoGHUhDL23KeKfvS
 github.com/VictoriaMetrics/metrics v1.12.2/go.mod h1:Z1tSfPfngDn12bTfZSCqArT3OPY3u88J12hSoOhuiRE=
 github.com/VictoriaMetrics/metrics v1.12.3 h1:Fe6JHC6MSEKa+BtLhPN8WIvS+HKPzMc2evEpNeCGy7I=
 github.com/VictoriaMetrics/metrics v1.12.3/go.mod h1:Z1tSfPfngDn12bTfZSCqArT3OPY3u88J12hSoOhuiRE=
-github.com/VictoriaMetrics/metricsql v0.6.0 h1:JnHUmifuA3fdy1GQrmkZJFO+CwFrhLxKwzMv89wNgJ4=
+github.com/VictoriaMetrics/metricsql v0.7.0 h1:YR/OvbsCH0dwUuc3r5GayTcuTdgWHJZo+4bqbaGl7WM=
-github.com/VictoriaMetrics/metricsql v0.6.0/go.mod h1:ylO7YITho/Iw6P71oEaGyHbO94bGoGtzWfLGqFhMIg8=
+github.com/VictoriaMetrics/metricsql v0.7.0/go.mod h1:ylO7YITho/Iw6P71oEaGyHbO94bGoGtzWfLGqFhMIg8=
 github.com/allegro/bigcache v1.2.1-0.20190218064605-e24eb225f156 h1:eMwmnE/GDgah4HI848JfFxHt+iPb26b4zyfspmqY0/8=
 github.com/allegro/bigcache v1.2.1-0.20190218064605-e24eb225f156/go.mod h1:Cb/ax3seSYIx7SuZdm2G2xzfwmv3TPSk2ucNfQESPXM=
 github.com/andybalholm/brotli v1.0.0/go.mod h1:loMXtMfwqflxFJPmdbJO0a3KNoPuLBgiu3qAvBg8x/Y=

vendor/github.com/VictoriaMetrics/metricsql/optimizer.go

@@ -0,0 +1,83 @@
+package metricsql
+
+import (
+	"sort"
+)
+
+// Optimize optimizes e in order to improve its performance.
+func Optimize(e Expr) Expr {
+	switch t := e.(type) {
+	case *BinaryOpExpr:
+		// Convert `foo{filters1} op bar{filters2}` to `foo{filters1, filters2} op bar{filters1, filters2}`.
+		// This should reduce the number of operations
+		// See https://utcc.utoronto.ca/~cks/space/blog/sysadmin/PrometheusLabelNonOptimization
+		// for details.
+		switch t.Op {
+		case "+", "-", "*", "/", "%", "^",
+			"==", "!=", ">", "<", ">=", "<=",
+			"if", "ifnot", "default":
+			// The optimization can be applied only to these operations.
+		default:
+			return optimizeBinaryOpArgs(t)
+		}
+		if t.JoinModifier.Op != "" {
+			return optimizeBinaryOpArgs(t)
+		}
+		if t.GroupModifier.Op != "" {
+			return optimizeBinaryOpArgs(t)
+		}
+		meLeft, ok := t.Left.(*MetricExpr)
+		if !ok || !meLeft.hasNonEmptyMetricGroup() {
+			return optimizeBinaryOpArgs(t)
+		}
+		meRight, ok := t.Right.(*MetricExpr)
+		if !ok || !meRight.hasNonEmptyMetricGroup() {
+			return optimizeBinaryOpArgs(t)
+		}
+		lfs := intersectLabelFilters(meLeft.LabelFilters[1:], meRight.LabelFilters[1:])
+		meLeft.LabelFilters = append(meLeft.LabelFilters[:1], lfs...)
+		meRight.LabelFilters = append(meRight.LabelFilters[:1], lfs...)
+		return t
+	case *FuncExpr:
+		for i := range t.Args {
+			t.Args[i] = Optimize(t.Args[i])
+		}
+		return t
+	case *AggrFuncExpr:
+		for i := range t.Args {
+			t.Args[i] = Optimize(t.Args[i])
+		}
+		return t
+	default:
+		return e
+	}
+}
+
+func optimizeBinaryOpArgs(be *BinaryOpExpr) *BinaryOpExpr {
+	be.Left = Optimize(be.Left)
+	be.Right = Optimize(be.Right)
+	return be
+}
+
+func intersectLabelFilters(a, b []LabelFilter) []LabelFilter {
+	m := make(map[string]LabelFilter, len(a)+len(b))
+	var buf []byte
+	for _, lf := range a {
+		buf = lf.AppendString(buf[:0])
+		m[string(buf)] = lf
+	}
+	for _, lf := range b {
+		buf = lf.AppendString(buf[:0])
+		m[string(buf)] = lf
+	}
+	ss := make([]string, 0, len(m))
+	for s := range m {
+		ss = append(ss, s)
+	}
+	sort.Strings(ss)
+	lfs := make([]LabelFilter, 0, len(ss))
+	for _, s := range ss {
+		lfs = append(lfs, m[s])
+	}
+	return lfs
+}

vendor/modules.txt

@@ -16,7 +16,7 @@ github.com/VictoriaMetrics/fasthttp/fasthttputil
 github.com/VictoriaMetrics/fasthttp/stackless
 # github.com/VictoriaMetrics/metrics v1.12.3
 github.com/VictoriaMetrics/metrics
-# github.com/VictoriaMetrics/metricsql v0.6.0
+# github.com/VictoriaMetrics/metricsql v0.7.0
 github.com/VictoriaMetrics/metricsql
 github.com/VictoriaMetrics/metricsql/binaryop
 # github.com/aws/aws-sdk-go v1.35.3