storage: improve label matching and allow unset matching.

Matching of empty labels now also matches metrics where the label
was not explicitly set to the empty string.

promql/analyzer.go

@@ -72,27 +72,24 @@ func (a *Analyzer) Analyze(ctx context.Context) error {
 	Inspect(a.Expr, func(node Node) bool {
 		switch n := node.(type) {
 		case *VectorSelector:
+			n.metrics = a.Storage.MetricsForLabelMatchers(n.LabelMatchers...)
+			n.iterators = make(map[clientmodel.Fingerprint]local.SeriesIterator, len(n.metrics))
+
 			pt := getPreloadTimes(n.Offset)
-			fpts := a.Storage.FingerprintsForLabelMatchers(n.LabelMatchers)
-			n.fingerprints = fpts
-			n.metrics = map[clientmodel.Fingerprint]clientmodel.COWMetric{}
-			n.iterators = map[clientmodel.Fingerprint]local.SeriesIterator{}
-			for _, fp := range fpts {
+			for fp := range n.metrics {
 				// Only add the fingerprint to the instants if not yet present in the
 				// ranges. Ranges always contain more points and span more time than
 				// instants for the same offset.
 				if _, alreadyInRanges := pt.ranges[fp]; !alreadyInRanges {
 					pt.instants[fp] = struct{}{}
 				}
-				n.metrics[fp] = a.Storage.MetricForFingerprint(fp)
 			}
 		case *MatrixSelector:
+			n.metrics = a.Storage.MetricsForLabelMatchers(n.LabelMatchers...)
+			n.iterators = make(map[clientmodel.Fingerprint]local.SeriesIterator, len(n.metrics))
+
 			pt := getPreloadTimes(n.Offset)
-			fpts := a.Storage.FingerprintsForLabelMatchers(n.LabelMatchers)
-			n.fingerprints = fpts
-			n.metrics = map[clientmodel.Fingerprint]clientmodel.COWMetric{}
-			n.iterators = map[clientmodel.Fingerprint]local.SeriesIterator{}
-			for _, fp := range fpts {
+			for fp := range n.metrics {
 				if pt.ranges[fp] < n.Range {
 					pt.ranges[fp] = n.Range
 					// Delete the fingerprint from the instants. Ranges always contain more
@@ -100,7 +97,6 @@ func (a *Analyzer) Analyze(ctx context.Context) error {
 					// an instant for the same fingerprint, should we have one.
 					delete(pt.instants, fp)
 				}
-				n.metrics[fp] = a.Storage.MetricForFingerprint(fp)
 			}
 		}
 		return true
@@ -157,11 +153,11 @@ func (a *Analyzer) Prepare(ctx context.Context) (local.Preloader, error) {
 	Inspect(a.Expr, func(node Node) bool {
 		switch n := node.(type) {
 		case *VectorSelector:
-			for _, fp := range n.fingerprints {
+			for fp := range n.metrics {
 				n.iterators[fp] = a.Storage.NewIterator(fp)
 			}
 		case *MatrixSelector:
-			for _, fp := range n.fingerprints {
+			for fp := range n.metrics {
 				n.iterators[fp] = a.Storage.NewIterator(fp)
 			}
 		}

promql/ast.go

@@ -161,8 +161,6 @@ type MatrixSelector struct {
 	// The series iterators are populated at query analysis time.
 	iterators map[clientmodel.Fingerprint]local.SeriesIterator
 	metrics   map[clientmodel.Fingerprint]clientmodel.COWMetric
-	// Fingerprints are populated from label matchers at query analysis time.
-	fingerprints clientmodel.Fingerprints
 }
 
 // NumberLiteral represents a number.
@@ -197,8 +195,6 @@ type VectorSelector struct {
 	// The series iterators are populated at query analysis time.
 	iterators map[clientmodel.Fingerprint]local.SeriesIterator
 	metrics   map[clientmodel.Fingerprint]clientmodel.COWMetric
-	// Fingerprints are populated from label matchers at query analysis time.
-	fingerprints clientmodel.Fingerprints
 }
 
 func (e *AggregateExpr) Type() ExprType  { return ExprVector }

storage/local/interface.go

@@ -36,9 +36,10 @@ type Storage interface {
 	// NewPreloader returns a new Preloader which allows preloading and pinning
 	// series data into memory for use within a query.
 	NewPreloader() Preloader
-	// Get all of the metric fingerprints that are associated with the
-	// provided label matchers.
-	FingerprintsForLabelMatchers(metric.LabelMatchers) clientmodel.Fingerprints
+	// MetricsForLabelMatchers returns the metrics from storage that satisfy the given
+	// label matchers. At least one label matcher must be specified that does not
+	// match the empty string.
+	MetricsForLabelMatchers(matchers ...*metric.LabelMatcher) map[clientmodel.Fingerprint]clientmodel.COWMetric
 	// Get all of the label values that are associated with a given label name.
 	LabelValuesForLabelName(clientmodel.LabelName) clientmodel.LabelValues
 	// Get the metric associated with the provided fingerprint.

storage/local/storage.go

@@ -336,54 +336,22 @@ func (s *memorySeriesStorage) NewPreloader() Preloader {
 	}
 }
 
-// FingerprintsForLabelMatchers implements Storage.
-func (s *memorySeriesStorage) FingerprintsForLabelMatchers(labelMatchers metric.LabelMatchers) clientmodel.Fingerprints {
+// fingerprintsForLabelPairs returns the set of fingerprints that have the given labels.
+// This does not work with empty label values.
+func (s *memorySeriesStorage) fingerprintsForLabelPairs(pairs ...metric.LabelPair) map[clientmodel.Fingerprint]struct{} {
 	var result map[clientmodel.Fingerprint]struct{}
-	for _, matcher := range labelMatchers {
+	for _, pair := range pairs {
 		intersection := map[clientmodel.Fingerprint]struct{}{}
-		switch matcher.Type {
-		case metric.Equal:
-			fps, err := s.persistence.fingerprintsForLabelPair(
-				metric.LabelPair{
-					Name:  matcher.Name,
-					Value: matcher.Value,
-				},
-			)
-			if err != nil {
-				log.Error("Error getting fingerprints for label pair: ", err)
-			}
-			if len(fps) == 0 {
-				return nil
-			}
-			for _, fp := range fps {
-				if _, ok := result[fp]; ok || result == nil {
-					intersection[fp] = struct{}{}
-				}
-			}
-		default:
-			values, err := s.persistence.labelValuesForLabelName(matcher.Name)
-			if err != nil {
-				log.Errorf("Error getting label values for label name %q: %v", matcher.Name, err)
-			}
-			matches := matcher.Filter(values)
-			if len(matches) == 0 {
-				return nil
-			}
-			for _, v := range matches {
-				fps, err := s.persistence.fingerprintsForLabelPair(
-					metric.LabelPair{
-						Name:  matcher.Name,
-						Value: v,
-					},
-				)
-				if err != nil {
-					log.Error("Error getting fingerprints for label pair: ", err)
-				}
-				for _, fp := range fps {
-					if _, ok := result[fp]; ok || result == nil {
-						intersection[fp] = struct{}{}
-					}
-				}
+		fps, err := s.persistence.fingerprintsForLabelPair(pair)
+		if err != nil {
+			log.Error("Error getting fingerprints for label pair: ", err)
+		}
+		if len(fps) == 0 {
+			return nil
+		}
+		for _, fp := range fps {
+			if _, ok := result[fp]; ok || result == nil {
+				intersection[fp] = struct{}{}
 			}
 		}
 		if len(intersection) == 0 {
@@ -391,12 +359,73 @@ func (s *memorySeriesStorage) FingerprintsForLabelMatchers(labelMatchers metric.
 		}
 		result = intersection
 	}
+	return result
+}
+
+// MetricsForLabelMatchers implements Storage.
+func (s *memorySeriesStorage) MetricsForLabelMatchers(matchers ...*metric.LabelMatcher) map[clientmodel.Fingerprint]clientmodel.COWMetric {
+	var (
+		equals  []metric.LabelPair
+		filters []*metric.LabelMatcher
+	)
+	for _, lm := range matchers {
+		if lm.Type == metric.Equal && lm.Value != "" {
+			equals = append(equals, metric.LabelPair{
+				Name:  lm.Name,
+				Value: lm.Value,
+			})
+		} else {
+			filters = append(filters, lm)
+		}
+	}
+
+	var resFPs map[clientmodel.Fingerprint]struct{}
+	// If we cannot make a preselection based on equality matchers, expanding the other matchers to labels
+	// and intersecting their fingerprints is still likely to be the best choice.
+	if len(equals) > 0 {
+		resFPs = s.fingerprintsForLabelPairs(equals...)
+	}
+	var remaining metric.LabelMatchers
+	for _, matcher := range filters {
+		// Equal matches are all empty values.
+		if matcher.Match("") {
+			remaining = append(remaining, matcher)
+			continue
+		}
+		intersection := map[clientmodel.Fingerprint]struct{}{}
 
-	fps := make(clientmodel.Fingerprints, 0, len(result))
-	for fp := range result {
-		fps = append(fps, fp)
+		matches := matcher.Filter(s.LabelValuesForLabelName(matcher.Name))
+		if len(matches) == 0 {
+			return nil
+		}
+		for _, v := range matches {
+			fps := s.fingerprintsForLabelPairs(metric.LabelPair{
+				Name:  matcher.Name,
+				Value: v,
+			})
+			for fp := range fps {
+				if _, ok := resFPs[fp]; ok || resFPs == nil {
+					intersection[fp] = struct{}{}
+				}
+			}
+		}
+		resFPs = intersection
+	}
+	// The intersected matchers no longer need to be compared against the actual metrics.
+	filters = remaining
+
+	result := make(map[clientmodel.Fingerprint]clientmodel.COWMetric, len(resFPs))
+	for fp := range resFPs {
+		result[fp] = s.MetricForFingerprint(fp)
+	}
+	for _, matcher := range filters {
+		for fp, met := range result {
+			if !matcher.Match(met.Metric[matcher.Name]) {
+				delete(result, fp)
+			}
+		}
 	}
-	return fps
+	return result
 }
 
 // LabelValuesForLabelName implements Storage.

storage/local/storage_test.go

@@ -29,7 +29,7 @@ import (
 	"github.com/prometheus/prometheus/util/testutil"
 )
 
-func TestFingerprintsForLabelMatchers(t *testing.T) {
+func TestMatches(t *testing.T) {
 	storage, closer := NewTestStorage(t, 1)
 	defer closer.Close()
 
@@ -41,6 +41,7 @@ func TestFingerprintsForLabelMatchers(t *testing.T) {
 			clientmodel.MetricNameLabel: clientmodel.LabelValue(fmt.Sprintf("test_metric_%d", i)),
 			"label1":                    clientmodel.LabelValue(fmt.Sprintf("test_%d", i/10)),
 			"label2":                    clientmodel.LabelValue(fmt.Sprintf("test_%d", (i+5)/10)),
+			"all":                       "const",
 		}
 		samples[i] = &clientmodel.Sample{
 			Metric:    metric,
@@ -82,15 +83,22 @@ func TestFingerprintsForLabelMatchers(t *testing.T) {
 			expected: fingerprints[5:10],
 		},
 		{
-			matchers: metric.LabelMatchers{newMatcher(metric.NotEqual, "label1", "x")},
+			matchers: metric.LabelMatchers{
+				newMatcher(metric.Equal, "all", "const"),
+				newMatcher(metric.NotEqual, "label1", "x"),
+			},
 			expected: fingerprints,
 		},
 		{
-			matchers: metric.LabelMatchers{newMatcher(metric.NotEqual, "label1", "test_0")},
+			matchers: metric.LabelMatchers{
+				newMatcher(metric.Equal, "all", "const"),
+				newMatcher(metric.NotEqual, "label1", "test_0"),
+			},
 			expected: fingerprints[10:],
 		},
 		{
 			matchers: metric.LabelMatchers{
+				newMatcher(metric.Equal, "all", "const"),
 				newMatcher(metric.NotEqual, "label1", "test_0"),
 				newMatcher(metric.NotEqual, "label1", "test_1"),
 				newMatcher(metric.NotEqual, "label1", "test_2"),
@@ -98,11 +106,44 @@ func TestFingerprintsForLabelMatchers(t *testing.T) {
 			expected: fingerprints[30:],
 		},
 		{
-			matchers: metric.LabelMatchers{newMatcher(metric.RegexMatch, "label1", `test_[3-5]`)},
+			matchers: metric.LabelMatchers{
+				newMatcher(metric.Equal, "label1", ""),
+			},
+			expected: fingerprints[:0],
+		},
+		{
+			matchers: metric.LabelMatchers{
+				newMatcher(metric.NotEqual, "label1", "test_0"),
+				newMatcher(metric.Equal, "label1", ""),
+			},
+			expected: fingerprints[:0],
+		},
+		{
+			matchers: metric.LabelMatchers{
+				newMatcher(metric.NotEqual, "label1", "test_0"),
+				newMatcher(metric.Equal, "label2", ""),
+			},
+			expected: fingerprints[:0],
+		},
+		{
+			matchers: metric.LabelMatchers{
+				newMatcher(metric.Equal, "all", "const"),
+				newMatcher(metric.NotEqual, "label1", "test_0"),
+				newMatcher(metric.Equal, "not_existant", ""),
+			},
+			expected: fingerprints[10:],
+		},
+		{
+			matchers: metric.LabelMatchers{
+				newMatcher(metric.RegexMatch, "label1", `test_[3-5]`),
+			},
 			expected: fingerprints[30:60],
 		},
 		{
-			matchers: metric.LabelMatchers{newMatcher(metric.RegexNoMatch, "label1", `test_[3-5]`)},
+			matchers: metric.LabelMatchers{
+				newMatcher(metric.Equal, "all", "const"),
+				newMatcher(metric.RegexNoMatch, "label1", `test_[3-5]`),
+			},
 			expected: append(append(clientmodel.Fingerprints{}, fingerprints[:30]...), fingerprints[60:]...),
 		},
 		{
@@ -122,11 +163,11 @@ func TestFingerprintsForLabelMatchers(t *testing.T) {
 	}
 
 	for _, mt := range matcherTests {
-		resfps := storage.FingerprintsForLabelMatchers(mt.matchers)
-		if len(mt.expected) != len(resfps) {
-			t.Fatalf("expected %d matches for %q, found %d", len(mt.expected), mt.matchers, len(resfps))
+		res := storage.MetricsForLabelMatchers(mt.matchers...)
+		if len(mt.expected) != len(res) {
+			t.Fatalf("expected %d matches for %q, found %d", len(mt.expected), mt.matchers, len(res))
 		}
-		for _, fp1 := range resfps {
+		for fp1 := range res {
 			found := false
 			for _, fp2 := range mt.expected {
 				if fp1 == fp2 {
@@ -141,6 +182,86 @@ func TestFingerprintsForLabelMatchers(t *testing.T) {
 	}
 }
 
+func TestFingerprintsForLabels(t *testing.T) {
+	storage, closer := NewTestStorage(t, 1)
+	defer closer.Close()
+
+	samples := make([]*clientmodel.Sample, 100)
+	fingerprints := make(clientmodel.Fingerprints, 100)
+
+	for i := range samples {
+		metric := clientmodel.Metric{
+			clientmodel.MetricNameLabel: clientmodel.LabelValue(fmt.Sprintf("test_metric_%d", i)),
+			"label1":                    clientmodel.LabelValue(fmt.Sprintf("test_%d", i/10)),
+			"label2":                    clientmodel.LabelValue(fmt.Sprintf("test_%d", (i+5)/10)),
+		}
+		samples[i] = &clientmodel.Sample{
+			Metric:    metric,
+			Timestamp: clientmodel.Timestamp(i),
+			Value:     clientmodel.SampleValue(i),
+		}
+		fingerprints[i] = metric.FastFingerprint()
+	}
+	for _, s := range samples {
+		storage.Append(s)
+	}
+	storage.WaitForIndexing()
+
+	var matcherTests = []struct {
+		pairs    []metric.LabelPair
+		expected clientmodel.Fingerprints
+	}{
+		{
+			pairs:    []metric.LabelPair{{"label1", "x"}},
+			expected: fingerprints[:0],
+		},
+		{
+			pairs:    []metric.LabelPair{{"label1", "test_0"}},
+			expected: fingerprints[:10],
+		},
+		{
+			pairs: []metric.LabelPair{
+				{"label1", "test_0"},
+				{"label1", "test_1"},
+			},
+			expected: fingerprints[:0],
+		},
+		{
+			pairs: []metric.LabelPair{
+				{"label1", "test_0"},
+				{"label2", "test_1"},
+			},
+			expected: fingerprints[5:10],
+		},
+		{
+			pairs: []metric.LabelPair{
+				{"label1", "test_1"},
+				{"label2", "test_2"},
+			},
+			expected: fingerprints[15:20],
+		},
+	}
+
+	for _, mt := range matcherTests {
+		resfps := storage.fingerprintsForLabelPairs(mt.pairs...)
+		if len(mt.expected) != len(resfps) {
+			t.Fatalf("expected %d matches for %q, found %d", len(mt.expected), mt.pairs, len(resfps))
+		}
+		for fp1 := range resfps {
+			found := false
+			for _, fp2 := range mt.expected {
+				if fp1 == fp2 {
+					found = true
+					break
+				}
+			}
+			if !found {
+				t.Errorf("expected fingerprint %s for %q not in result", fp1, mt.pairs)
+			}
+		}
+	}
+}
+
 var benchLabelMatchingRes map[clientmodel.Fingerprint]clientmodel.COWMetric
 
 func BenchmarkLabelMatching(b *testing.B) {
@@ -226,9 +347,7 @@ func BenchmarkLabelMatching(b *testing.B) {
 	for i := 0; i < b.N; i++ {
 		benchLabelMatchingRes = map[clientmodel.Fingerprint]clientmodel.COWMetric{}
 		for _, mt := range matcherTests {
-			for _, fp := range s.FingerprintsForLabelMatchers(mt) {
-				benchLabelMatchingRes[fp] = s.MetricForFingerprint(fp)
-			}
+			benchLabelMatchingRes = s.MetricsForLabelMatchers(mt...)
 		}
 	}
 	// Stop timer to not count the storage closing.
@@ -257,17 +376,17 @@ func TestRetentionCutoff(t *testing.T) {
 	}
 	s.WaitForIndexing()
 
-	lm, err := metric.NewLabelMatcher(metric.Equal, "job", "test")
-	if err != nil {
-		t.Fatalf("error creating label matcher: %s", err)
+	var fp clientmodel.Fingerprint
+	for f := range s.fingerprintsForLabelPairs(metric.LabelPair{"job", "test"}) {
+		fp = f
+		break
 	}
-	fp := s.FingerprintsForLabelMatchers(metric.LabelMatchers{lm})[0]
 
 	pl := s.NewPreloader()
 	defer pl.Close()
 
 	// Preload everything.
-	err = pl.PreloadRange(fp, insertStart, now, 5*time.Minute)
+	err := pl.PreloadRange(fp, insertStart, now, 5*time.Minute)
 	if err != nil {
 		t.Fatalf("Error preloading outdated chunks: %s", err)
 	}
@@ -322,56 +441,50 @@ func TestDropMetrics(t *testing.T) {
 	}
 	s.WaitForIndexing()
 
-	matcher := metric.LabelMatchers{{
-		Type:  metric.Equal,
-		Name:  clientmodel.MetricNameLabel,
-		Value: "test",
-	}}
-
-	fps := s.FingerprintsForLabelMatchers(matcher)
+	fps := s.fingerprintsForLabelPairs(metric.LabelPair{clientmodel.MetricNameLabel, "test"})
 	if len(fps) != 2 {
 		t.Fatalf("unexpected number of fingerprints: %d", len(fps))
 	}
 
-	it := s.NewIterator(fps[0])
-	if vals := it.RangeValues(metric.Interval{insertStart, now}); len(vals) != N {
-		t.Fatalf("unexpected number of samples: %d", len(vals))
-	}
-	it = s.NewIterator(fps[1])
-	if vals := it.RangeValues(metric.Interval{insertStart, now}); len(vals) != N {
-		t.Fatalf("unexpected number of samples: %d", len(vals))
+	var fpList clientmodel.Fingerprints
+	for fp := range fps {
+		it := s.NewIterator(fp)
+		if vals := it.RangeValues(metric.Interval{insertStart, now}); len(vals) != N {
+			t.Fatalf("unexpected number of samples: %d", len(vals))
+		}
+		fpList = append(fpList, fp)
 	}
 
-	s.DropMetricsForFingerprints(fps[0])
+	s.DropMetricsForFingerprints(fpList[0])
 	s.WaitForIndexing()
 
-	fps2 := s.FingerprintsForLabelMatchers(matcher)
+	fps2 := s.fingerprintsForLabelPairs(metric.LabelPair{clientmodel.MetricNameLabel, "test"})
 	if len(fps2) != 1 {
 		t.Fatalf("unexpected number of fingerprints: %d", len(fps2))
 	}
 
-	it = s.NewIterator(fps[0])
+	it := s.NewIterator(fpList[0])
 	if vals := it.RangeValues(metric.Interval{insertStart, now}); len(vals) != 0 {
 		t.Fatalf("unexpected number of samples: %d", len(vals))
 	}
-	it = s.NewIterator(fps[1])
+	it = s.NewIterator(fpList[1])
 	if vals := it.RangeValues(metric.Interval{insertStart, now}); len(vals) != N {
 		t.Fatalf("unexpected number of samples: %d", len(vals))
 	}
 
-	s.DropMetricsForFingerprints(fps...)
+	s.DropMetricsForFingerprints(fpList...)
 	s.WaitForIndexing()
 
-	fps3 := s.FingerprintsForLabelMatchers(matcher)
+	fps3 := s.fingerprintsForLabelPairs(metric.LabelPair{clientmodel.MetricNameLabel, "test"})
 	if len(fps3) != 0 {
 		t.Fatalf("unexpected number of fingerprints: %d", len(fps3))
 	}
 
-	it = s.NewIterator(fps[0])
+	it = s.NewIterator(fpList[0])
 	if vals := it.RangeValues(metric.Interval{insertStart, now}); len(vals) != 0 {
 		t.Fatalf("unexpected number of samples: %d", len(vals))
 	}
-	it = s.NewIterator(fps[1])
+	it = s.NewIterator(fpList[1])
 	if vals := it.RangeValues(metric.Interval{insertStart, now}); len(vals) != 0 {
 		t.Fatalf("unexpected number of samples: %d", len(vals))
 	}

web/api/v1/api.go

@@ -188,23 +188,21 @@ func (api *API) series(r *http.Request) (interface{}, *apiError) {
 	if len(r.Form["match[]"]) == 0 {
 		return nil, &apiError{errorBadData, fmt.Errorf("no match[] parameter provided")}
 	}
-	fps := map[clientmodel.Fingerprint]struct{}{}
+	res := map[clientmodel.Fingerprint]clientmodel.COWMetric{}
 
 	for _, lm := range r.Form["match[]"] {
 		matchers, err := promql.ParseMetricSelector(lm)
 		if err != nil {
 			return nil, &apiError{errorBadData, err}
 		}
-		for _, fp := range api.Storage.FingerprintsForLabelMatchers(matchers) {
-			fps[fp] = struct{}{}
+		for fp, met := range api.Storage.MetricsForLabelMatchers(matchers...) {
+			res[fp] = met
 		}
 	}
 
-	metrics := make([]clientmodel.Metric, 0, len(fps))
-	for fp := range fps {
-		if met := api.Storage.MetricForFingerprint(fp).Metric; met != nil {
-			metrics = append(metrics, met)
-		}
+	metrics := make([]clientmodel.Metric, 0, len(res))
+	for _, met := range res {
+		metrics = append(metrics, met.Metric)
 	}
 	return metrics, nil
 }
@@ -221,7 +219,7 @@ func (api *API) dropSeries(r *http.Request) (interface{}, *apiError) {
 		if err != nil {
 			return nil, &apiError{errorBadData, err}
 		}
-		for _, fp := range api.Storage.FingerprintsForLabelMatchers(matchers) {
+		for fp := range api.Storage.MetricsForLabelMatchers(matchers...) {
 			fps[fp] = struct{}{}
 		}
 	}