Add metric for number of series with discarded samples

CHANGELOG.md

@@ -77,6 +77,7 @@
 * [ENHANCEMENT] Upgrade build image and Go version to 1.24.6. #6970 #6976
 * [ENHANCEMENT] Implement versioned transactions for writes to DynamoDB ring. #6986
 * [ENHANCEMENT] Add source metadata to requests(api vs ruler) #6947
+* [ENHANCEMENT] Add new metric `cortex_discarded_series` and `cortex_discarded_series_per_labelset` to track number of series that have a discarded sample. #6995
 * [BUGFIX] Ingester: Avoid error or early throttling when READONLY ingesters are present in the ring #6517
 * [BUGFIX] Ingester: Fix labelset data race condition. #6573
 * [BUGFIX] Compactor: Cleaner should not put deletion marker for blocks with no-compact marker. #6576

pkg/ingester/ingester.go

@@ -1259,22 +1259,27 @@ func (i *Ingester) Push(ctx context.Context, req *cortexpb.WriteRequest) (*corte
 			switch cause := errors.Cause(err); {
 			case errors.Is(cause, storage.ErrOutOfBounds):
 				sampleOutOfBoundsCount++
+				i.validateMetrics.DiscardedSeriesTracker.Track(sampleOutOfBounds, userID, copiedLabels.Hash())
 				updateFirstPartial(func() error { return wrappedTSDBIngestErr(err, model.Time(timestampMs), lbls) })
 
 			case errors.Is(cause, storage.ErrOutOfOrderSample):
 				sampleOutOfOrderCount++
+				i.validateMetrics.DiscardedSeriesTracker.Track(sampleOutOfOrder, userID, copiedLabels.Hash())
 				updateFirstPartial(func() error { return wrappedTSDBIngestErr(err, model.Time(timestampMs), lbls) })
 
 			case errors.Is(cause, storage.ErrDuplicateSampleForTimestamp):
 				newValueForTimestampCount++
+				i.validateMetrics.DiscardedSeriesTracker.Track(newValueForTimestamp, userID, copiedLabels.Hash())
 				updateFirstPartial(func() error { return wrappedTSDBIngestErr(err, model.Time(timestampMs), lbls) })
 
 			case errors.Is(cause, storage.ErrTooOldSample):
 				sampleTooOldCount++
+				i.validateMetrics.DiscardedSeriesTracker.Track(sampleTooOld, userID, copiedLabels.Hash())
 				updateFirstPartial(func() error { return wrappedTSDBIngestErr(err, model.Time(timestampMs), lbls) })
 
 			case errors.Is(cause, errMaxSeriesPerUserLimitExceeded):
 				perUserSeriesLimitCount++
+				i.validateMetrics.DiscardedSeriesTracker.Track(perUserSeriesLimit, userID, copiedLabels.Hash())
 				updateFirstPartial(func() error {
 					return makeLimitError(perUserSeriesLimit, i.limiter.FormatError(userID, cause, copiedLabels))
 				})
@@ -1287,12 +1292,17 @@ func (i *Ingester) Push(ctx context.Context, req *cortexpb.WriteRequest) (*corte
 
 			case errors.Is(cause, errMaxSeriesPerMetricLimitExceeded):
 				perMetricSeriesLimitCount++
+				i.validateMetrics.DiscardedSeriesTracker.Track(perMetricSeriesLimit, userID, copiedLabels.Hash())
 				updateFirstPartial(func() error {
 					return makeMetricLimitError(perMetricSeriesLimit, copiedLabels, i.limiter.FormatError(userID, cause, copiedLabels))
 				})
 
 			case errors.As(cause, &errMaxSeriesPerLabelSetLimitExceeded{}):
 				perLabelSetSeriesLimitCount++
+				i.validateMetrics.DiscardedSeriesTracker.Track(perLabelsetSeriesLimit, userID, copiedLabels.Hash())
+				for _, matchedLabelset := range matchedLabelSetLimits {
+					i.validateMetrics.DiscardedSeriesPerLabelsetTracker.Track(userID, copiedLabels.Hash(), matchedLabelset.Hash, matchedLabelset.Id)
+				}
 				// We only track per labelset discarded samples for throttling by labelset limit.
 				reasonCounter.increment(matchedLabelSetLimits, perLabelsetSeriesLimit)
 				updateFirstPartial(func() error {

pkg/util/discardedseries/perlabelset_tracker.go

@@ -0,0 +1,141 @@
+package discardedseries
+
+import (
+	"sync"
+	"time"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+// TODO: if we change per labelset series limit from one reasoning to many, we can remove the hardcoded reasoning and add an extra reasoning map
+const (
+	perLabelsetSeriesLimit = "per_labelset_series_limit"
+)
+
+type labelsetCounterStruct struct {
+	*sync.RWMutex
+	labelsetSeriesMap map[uint64]*seriesCounterStruct
+}
+
+type DiscardedSeriesPerLabelsetTracker struct {
+	*sync.RWMutex
+	userLabelsetMap                 map[string]*labelsetCounterStruct
+	discardedSeriesPerLabelsetGauge *prometheus.GaugeVec
+}
+
+func NewDiscardedSeriesPerLabelsetTracker(discardedSeriesPerLabelsetGauge *prometheus.GaugeVec) *DiscardedSeriesPerLabelsetTracker {
+	tracker := &DiscardedSeriesPerLabelsetTracker{
+		RWMutex:                         &sync.RWMutex{},
+		userLabelsetMap:                 make(map[string]*labelsetCounterStruct),
+		discardedSeriesPerLabelsetGauge: discardedSeriesPerLabelsetGauge,
+	}
+	return tracker
+}
+
+func (t *DiscardedSeriesPerLabelsetTracker) Track(user string, series uint64, matchedLabelsetHash uint64, matchedLabelsetId string) {
+	t.RLock()
+	labelsetCounter, ok := t.userLabelsetMap[user]
+	t.RUnlock()
+	if !ok {
+		t.Lock()
+		labelsetCounter, ok = t.userLabelsetMap[user]
+		if !ok {
+			labelsetCounter = &labelsetCounterStruct{
+				RWMutex:           &sync.RWMutex{},
+				labelsetSeriesMap: make(map[uint64]*seriesCounterStruct),
+			}
+			t.userLabelsetMap[user] = labelsetCounter
+		}
+		t.Unlock()
+	}
+
+	labelsetCounter.RLock()
+	seriesCounter, ok := labelsetCounter.labelsetSeriesMap[matchedLabelsetHash]
+	labelsetCounter.RUnlock()
+	if !ok {
+		labelsetCounter.Lock()
+		seriesCounter, ok = labelsetCounter.labelsetSeriesMap[matchedLabelsetHash]
+		if !ok {
+			seriesCounter = &seriesCounterStruct{
+				RWMutex:        &sync.RWMutex{},
+				seriesCountMap: make(map[uint64]struct{}),
+				labelsetId:     matchedLabelsetId,
+			}
+			labelsetCounter.labelsetSeriesMap[matchedLabelsetHash] = seriesCounter
+		}
+		labelsetCounter.Unlock()
+	}
+
+	seriesCounter.RLock()
+	_, ok = seriesCounter.seriesCountMap[series]
+	seriesCounter.RUnlock()
+	if !ok {
+		seriesCounter.Lock()
+		_, ok = seriesCounter.seriesCountMap[series]
+		if !ok {
+			seriesCounter.seriesCountMap[series] = struct{}{}
+		}
+		seriesCounter.Unlock()
+	}
+}
+
+func (t *DiscardedSeriesPerLabelsetTracker) UpdateMetrics() {
+	usersToDelete := make([]string, 0)
+	labelsetsToDelete := make([]uint64, 0)
+	t.RLock()
+	for user, labelsetCounter := range t.userLabelsetMap {
+		labelsetCounter.RLock()
+		if len(labelsetCounter.labelsetSeriesMap) == 0 {
+			usersToDelete = append(usersToDelete, user)
+		}
+		for labelsetHash, seriesCounter := range labelsetCounter.labelsetSeriesMap {
+			seriesCounter.Lock()
+			count := len(seriesCounter.seriesCountMap)
+			t.discardedSeriesPerLabelsetGauge.WithLabelValues(perLabelsetSeriesLimit, user, seriesCounter.labelsetId).Set(float64(count))
+			clear(seriesCounter.seriesCountMap)
+			if count == 0 {
+				labelsetsToDelete = append(labelsetsToDelete, labelsetHash)
+			}
+			seriesCounter.Unlock()
+		}
+		labelsetCounter.RUnlock()
+		if len(labelsetsToDelete) > 0 {
+			labelsetCounter.Lock()
+			for _, labelsetHash := range labelsetsToDelete {
+				if _, ok := labelsetCounter.labelsetSeriesMap[labelsetHash]; ok {
+					labelsetId := labelsetCounter.labelsetSeriesMap[labelsetHash].labelsetId
+					t.discardedSeriesPerLabelsetGauge.DeleteLabelValues(perLabelsetSeriesLimit, user, labelsetId)
+					delete(labelsetCounter.labelsetSeriesMap, labelsetHash)
+				}
+			}
+			labelsetCounter.Unlock()
+		}
+	}
+	t.RUnlock()
+	if len(usersToDelete) > 0 {
+		t.Lock()
+		for _, user := range usersToDelete {
+			delete(t.userLabelsetMap, user)
+		}
+		t.Unlock()
+	}
+}
+
+func (t *DiscardedSeriesPerLabelsetTracker) StartVendDiscardedSeriesMetricGoroutine() {
+	go func() {
+		ticker := time.NewTicker(vendMetricsInterval)
+		for range ticker.C {
+			t.UpdateMetrics()
+		}
+	}()
+}
+
+// only used in testing
+func (t *DiscardedSeriesPerLabelsetTracker) getSeriesCount(user string, labelsetLimitHash uint64) int {
+	if labelsetCounter, ok := t.userLabelsetMap[user]; ok {
+		if seriesCounter, ok := labelsetCounter.labelsetSeriesMap[labelsetLimitHash]; ok {
+			return len(seriesCounter.seriesCountMap)
+		}
+	}
+	return 0
+}

pkg/util/discardedseries/perlabelset_tracker_test.go

@@ -0,0 +1,118 @@
+package discardedseries
+
+import (
+	"testing"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/testutil"
+	"github.com/prometheus/prometheus/model/labels"
+	"github.com/stretchr/testify/require"
+)
+
+func TestPerLabelsetDiscardedSeriesTracker(t *testing.T) {
+	gauge := prometheus.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Name: "cortex_discarded_series_per_labelset",
+			Help: "The number of series that include discarded samples for each labelset.",
+		},
+		[]string{"reason", "user", "labelset"},
+	)
+
+	tracker := NewDiscardedSeriesPerLabelsetTracker(gauge)
+	user1 := "user1"
+	user2 := "user2"
+	series1 := labels.FromStrings("__name__", "1")
+	series2 := labels.FromStrings("__name__", "2")
+	labelset1 := uint64(10)
+	labelset2 := uint64(20)
+	labelset3 := uint64(30)
+	labelsetId1 := "ten"
+	labelsetId2 := "twenty"
+	labelsetId3 := "thirty"
+
+	tracker.Track(user1, series1.Hash(), labelset1, labelsetId1)
+	tracker.Track(user1, series1.Hash(), labelset2, labelsetId2)
+
+	tracker.Track(user2, series1.Hash(), labelset1, labelsetId1)
+	tracker.Track(user2, series1.Hash(), labelset1, labelsetId1)
+	tracker.Track(user2, series1.Hash(), labelset1, labelsetId1)
+	tracker.Track(user2, series2.Hash(), labelset1, labelsetId1)
+
+	require.Equal(t, tracker.getSeriesCount(user1, labelset1), 1)
+	require.Equal(t, tracker.getSeriesCount(user1, labelset2), 1)
+	require.Equal(t, tracker.getSeriesCount(user1, labelset3), 0)
+
+	comparePerLabelsetSeriesVendedCount(t, gauge, user1, labelsetId1, 0)
+	comparePerLabelsetSeriesVendedCount(t, gauge, user1, labelsetId2, 0)
+	comparePerLabelsetSeriesVendedCount(t, gauge, user1, labelsetId3, 0)
+
+	require.Equal(t, tracker.getSeriesCount(user2, labelset1), 2)
+	require.Equal(t, tracker.getSeriesCount(user2, labelset2), 0)
+	require.Equal(t, tracker.getSeriesCount(user2, labelset3), 0)
+
+	comparePerLabelsetSeriesVendedCount(t, gauge, user2, labelsetId1, 0)
+	comparePerLabelsetSeriesVendedCount(t, gauge, user2, labelsetId2, 0)
+	comparePerLabelsetSeriesVendedCount(t, gauge, user2, labelsetId3, 0)
+
+	tracker.UpdateMetrics()
+
+	tracker.Track(user1, series1.Hash(), labelset1, labelsetId1)
+	tracker.Track(user1, series1.Hash(), labelset1, labelsetId1)
+
+	require.Equal(t, tracker.getSeriesCount(user1, labelset1), 1)
+	require.Equal(t, tracker.getSeriesCount(user1, labelset2), 0)
+	require.Equal(t, tracker.getSeriesCount(user1, labelset3), 0)
+
+	comparePerLabelsetSeriesVendedCount(t, gauge, user1, labelsetId1, 1)
+	comparePerLabelsetSeriesVendedCount(t, gauge, user1, labelsetId2, 1)
+	comparePerLabelsetSeriesVendedCount(t, gauge, user1, labelsetId3, 0)
+
+	require.Equal(t, tracker.getSeriesCount(user2, labelset1), 0)
+	require.Equal(t, tracker.getSeriesCount(user2, labelset2), 0)
+	require.Equal(t, tracker.getSeriesCount(user2, labelset3), 0)
+
+	comparePerLabelsetSeriesVendedCount(t, gauge, user2, labelsetId1, 2)
+	comparePerLabelsetSeriesVendedCount(t, gauge, user2, labelsetId2, 0)
+	comparePerLabelsetSeriesVendedCount(t, gauge, user2, labelsetId3, 0)
+
+	tracker.UpdateMetrics()
+
+	require.Equal(t, tracker.getSeriesCount(user1, labelset1), 0)
+	require.Equal(t, tracker.getSeriesCount(user1, labelset2), 0)
+	require.Equal(t, tracker.getSeriesCount(user1, labelset3), 0)
+
+	comparePerLabelsetSeriesVendedCount(t, gauge, user1, labelsetId1, 1)
+	comparePerLabelsetSeriesVendedCount(t, gauge, user1, labelsetId2, 0)
+	comparePerLabelsetSeriesVendedCount(t, gauge, user1, labelsetId3, 0)
+
+	require.Equal(t, tracker.getSeriesCount(user2, labelset1), 0)
+	require.Equal(t, tracker.getSeriesCount(user2, labelset2), 0)
+	require.Equal(t, tracker.getSeriesCount(user2, labelset3), 0)
+
+	comparePerLabelsetSeriesVendedCount(t, gauge, user2, labelsetId1, 0)
+	comparePerLabelsetSeriesVendedCount(t, gauge, user2, labelsetId2, 0)
+	comparePerLabelsetSeriesVendedCount(t, gauge, user2, labelsetId3, 0)
+
+	tracker.UpdateMetrics()
+
+	require.Equal(t, tracker.getSeriesCount(user1, labelset1), 0)
+	require.Equal(t, tracker.getSeriesCount(user1, labelset2), 0)
+	require.Equal(t, tracker.getSeriesCount(user1, labelset3), 0)
+
+	comparePerLabelsetSeriesVendedCount(t, gauge, user1, labelsetId1, 0)
+	comparePerLabelsetSeriesVendedCount(t, gauge, user1, labelsetId2, 0)
+	comparePerLabelsetSeriesVendedCount(t, gauge, user1, labelsetId3, 0)
+
+	require.Equal(t, tracker.getSeriesCount(user2, labelset1), 0)
+	require.Equal(t, tracker.getSeriesCount(user2, labelset2), 0)
+	require.Equal(t, tracker.getSeriesCount(user2, labelset3), 0)
+
+	comparePerLabelsetSeriesVendedCount(t, gauge, user2, labelsetId1, 0)
+	comparePerLabelsetSeriesVendedCount(t, gauge, user2, labelsetId2, 0)
+	comparePerLabelsetSeriesVendedCount(t, gauge, user2, labelsetId3, 0)
+}
+
+func comparePerLabelsetSeriesVendedCount(t *testing.T, gaugeVec *prometheus.GaugeVec, user string, labelsetLimitId string, val int) {
+	gauge, _ := gaugeVec.GetMetricWithLabelValues("per_labelset_series_limit", user, labelsetLimitId)
+	require.Equal(t, testutil.ToFloat64(gauge), float64(val))
+}