Track number of optimised regexp label matchers

CHANGELOG.md

@@ -44,6 +44,7 @@
 * [ENHANCEMENT] Add native histogram support for `cortex_request_duration_seconds` metric family. #4987
 * [ENHANCEMENT] Ruler: do not list rule groups in the object storage for disabled tenants. #5004
 * [ENHANCEMENT] Query-frontend and querier: add HTTP API endpoint `<prometheus-http-prefix>/api/v1/format_query` to format a PromQL query. #4373
+* [ENHANCEMENT] Query-frontend: Add `cortex_query_frontend_regexp_matcher_count` and `cortex_query_frontend_regexp_matcher_optimized_count` metrics to track optimization of regular expression label matchers. #4813
 * [ENHANCEMENT] Alertmanager: Add configuration option to enable or disable the deletion of alertmanager state from object storage. This is useful when migrating alertmanager tenants from one cluster to another, because it avoids a condition where the state object is copied but then deleted before the configuration object is copied. #4989
 * [ENHANCEMENT] Querier: only use the minimum set of chunks from ingesters when querying, and cancel unnecessary requests to ingesters sooner if we know their results won't be used. #5016
 * [ENHANCEMENT] Add `-enable-go-runtime-metrics` flag to expose all go runtime metrics as Prometheus metrics. #5009

pkg/frontend/querymiddleware/stats.go

@@ -7,23 +7,37 @@ import (
 
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promauto"
+	"github.com/prometheus/prometheus/model/labels"
+	"github.com/prometheus/prometheus/promql/parser"
 )
 
 type queryStatsMiddleware struct {
-	nonAlignedQueries prometheus.Counter
-	next              Handler
+	nonAlignedQueries           prometheus.Counter
+	regexpMatcherCount          prometheus.Counter
+	regexpMatcherOptimizedCount prometheus.Counter
+	next                        Handler
 }
 
 func newQueryStatsMiddleware(reg prometheus.Registerer) Middleware {
 	nonAlignedQueries := promauto.With(reg).NewCounter(prometheus.CounterOpts{
 		Name: "cortex_query_frontend_non_step_aligned_queries_total",
 		Help: "Total queries sent that are not step aligned.",
 	})
+	regexpMatcherCount := promauto.With(reg).NewCounter(prometheus.CounterOpts{
+		Name: "cortex_query_frontend_regexp_matcher_count",
+		Help: "Total number of regexp matchers",
+	})
+	regexpMatcherOptimizedCount := promauto.With(reg).NewCounter(prometheus.CounterOpts{
+		Name: "cortex_query_frontend_regexp_matcher_optimized_count",
+		Help: "Total number of optimized regexp matchers",
+	})
 
 	return MiddlewareFunc(func(next Handler) Handler {
 		return &queryStatsMiddleware{
-			nonAlignedQueries: nonAlignedQueries,
-			next:              next,
+			nonAlignedQueries:           nonAlignedQueries,
+			regexpMatcherCount:          regexpMatcherCount,
+			regexpMatcherOptimizedCount: regexpMatcherOptimizedCount,
+			next:                        next,
 		}
 	})
 }
@@ -33,5 +47,20 @@ func (s queryStatsMiddleware) Do(ctx context.Context, req Request) (Response, er
 		s.nonAlignedQueries.Inc()
 	}
 
+	if expr, err := parser.ParseExpr(req.GetQuery()); err == nil {
+		for _, selectors := range parser.ExtractSelectors(expr) {
+			for _, matcher := range selectors {
+				if matcher.Type != labels.MatchRegexp && matcher.Type != labels.MatchNotRegexp {
+					continue
+				}
+
+				s.regexpMatcherCount.Inc()
+				if matcher.IsRegexOptimized() {
+					s.regexpMatcherOptimizedCount.Inc()
+				}
+			}
+		}
+	}
+
 	return s.next.Do(ctx, req)
 }

pkg/frontend/querymiddleware/stats_test.go

@@ -0,0 +1,84 @@
+// SPDX-License-Identifier: AGPL-3.0-only
+
+package querymiddleware
+
+import (
+	"context"
+	"strings"
+	"testing"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/testutil"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"github.com/weaveworks/common/user"
+
+	"github.com/grafana/mimir/pkg/util"
+)
+
+func Test_queryStatsMiddleware_Do(t *testing.T) {
+	type args struct {
+		req Request
+	}
+	tests := []struct {
+		name            string
+		args            args
+		expectedMetrics *strings.Reader
+	}{
+		{
+			name: "happy path",
+			args: args{
+				req: &PrometheusRangeQueryRequest{
+					Path:  "/query_range",
+					Start: util.TimeToMillis(start),
+					End:   util.TimeToMillis(end),
+					Step:  step.Milliseconds(),
+					Query: `sum(sum_over_time(metric{app="test",namespace=~"short"}[5m]))`,
+				},
+			},
+			expectedMetrics: strings.NewReader(`
+			# HELP cortex_query_frontend_non_step_aligned_queries_total Total queries sent that are not step aligned.
+			# TYPE cortex_query_frontend_non_step_aligned_queries_total counter
+			cortex_query_frontend_non_step_aligned_queries_total 1
+			# HELP cortex_query_frontend_regexp_matcher_count Total number of regexp matchers
+			# TYPE cortex_query_frontend_regexp_matcher_count counter
+			cortex_query_frontend_regexp_matcher_count 1
+			# HELP cortex_query_frontend_regexp_matcher_optimized_count Total number of optimized regexp matchers
+			# TYPE cortex_query_frontend_regexp_matcher_optimized_count counter
+			cortex_query_frontend_regexp_matcher_optimized_count 1
+			`),
+		},
+		{
+			name: "parseExpr failed",
+			args: args{
+				req: &PrometheusRangeQueryRequest{
+					Path:  "/query_range",
+					Start: util.TimeToMillis(start),
+					End:   util.TimeToMillis(end),
+					Step:  step.Milliseconds(),
+					Query: `?`,
+				},
+			},
+			expectedMetrics: strings.NewReader(`
+			# HELP cortex_query_frontend_non_step_aligned_queries_total Total queries sent that are not step aligned.
+			# TYPE cortex_query_frontend_non_step_aligned_queries_total counter
+			cortex_query_frontend_non_step_aligned_queries_total 1
+			# HELP cortex_query_frontend_regexp_matcher_count Total number of regexp matchers
+			# TYPE cortex_query_frontend_regexp_matcher_count counter
+			cortex_query_frontend_regexp_matcher_count 0
+			# HELP cortex_query_frontend_regexp_matcher_optimized_count Total number of optimized regexp matchers
+			# TYPE cortex_query_frontend_regexp_matcher_optimized_count counter
+			cortex_query_frontend_regexp_matcher_optimized_count 0
+			`),
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			reg := prometheus.NewPedanticRegistry()
+			mw := newQueryStatsMiddleware(reg)
+			_, err := mw.Wrap(mockHandlerWith(nil, nil)).Do(user.InjectOrgID(context.Background(), "test"), tt.args.req)
+			require.NoError(t, err)
+			assert.NoError(t, testutil.GatherAndCompare(reg, tt.expectedMetrics))
+		})
+	}
+}