enforce max series for metrics queries

CHANGELOG.md

@@ -17,6 +17,7 @@
 * [CHANGE] **BREAKING CHANGE** Enforce max attribute size at event, link, and instrumentation scope. Make config per-tenant.
   Renamed max_span_attr_byte to max_attribute_bytes
   [#4633](https://github.com/grafana/tempo/pull/4633) (@ie-pham)
+* [CHANGE] Enforce max series in response for metrics queries [#4525](https://github.com/grafana/tempo/pull/4525) (@ie-pham)
 * [ENHANCEMENT] Update minio to version [#4341](https://github.com/grafana/tempo/pull/4568) (@javiermolinar)
 * [ENHANCEMENT] Prevent queries in the ingester from blocking flushing traces to disk and memory spikes. [#4483](https://github.com/grafana/tempo/pull/4483) (@joe-elliott)
 * [ENHANCEMENT] Update tempo operational dashboard for new block-builder and v2 traces api [#4559](https://github.com/grafana/tempo/pull/4559) (@mdisibio)

docs/sources/tempo/configuration/_index.md

@@ -743,6 +743,9 @@ query_frontend:
         # Maximun number of exemplars per range query. Limited to 100.
         [max_exemplars: <int> | default = 100 ]
 
+        # Maximum number of time series returned for a metrics query.
+        [max_response_series: <int> | default = 1000]
+
         # query_backend_after controls where the query-frontend searches for traces.
         # Time ranges older than query_backend_after will be searched in the backend/object storage only.
         # Time ranges between query_backend_after and now will be queried from the metrics-generators.
@@ -838,6 +841,10 @@ querier:
         # the address of the query frontend to connect to, and process queries
         # Example: "frontend_address: query-frontend-discovery.default.svc.cluster.local:9095"
         [frontend_address: <string>]
+
+    metrics:
+        # Maximum number of time series returned for a metrics query.
+        [max_response_series: <int> | default = 1000]
 ```
 
 It also queries compacted blocks that fall within the (2 * BlocklistPoll) range where the value of Blocklist poll duration

docs/sources/tempo/configuration/manifest.md

@@ -274,6 +274,7 @@ querier:
     metrics:
         concurrent_blocks: 2
         time_overlap_cutoff: 0.2
+        max_response_series: 1000
     max_concurrent_queries: 20
     frontend_worker:
         frontend_address: ""
@@ -332,6 +333,7 @@ query_frontend:
         query_backend_after: 30m0s
         interval: 5m0s
         max_exemplars: 100
+        max_response_series: 1000
     multi_tenant_queries_enabled: true
     response_consumers: 10
     weights:

integration/e2e/config-query-range-max-series.yaml

@@ -0,0 +1,81 @@
+target: all
+stream_over_http_enabled: true
+
+server:
+  http_listen_port: 3200
+  log_level: debug
+
+query_frontend:
+  search:
+    query_backend_after: 0 # setting these both to 0 will force all range searches to hit the backend
+    query_ingesters_until: 0
+  metrics:
+    max_response_series: 3
+
+
+distributor:
+  receivers:
+    jaeger:
+      protocols:
+        grpc:
+          endpoint: "tempo:14250"
+    otlp:
+      protocols:
+        grpc:
+          endpoint: "tempo:4317"
+    zipkin:
+      endpoint: "tempo:9411"
+  log_received_spans:
+    enabled: true
+
+metrics_generator:
+  processor:
+    local_blocks:
+      flush_check_period: 1s
+      max_block_duration: 10s
+      flush_to_storage: true
+  storage:
+    path: /var/tempo
+    remote_write:
+      - url: http://tempo_e2e-prometheus:9090/api/v1/write
+        send_exemplars: true
+  traces_storage:
+    path: /var/tempo/generator/traces
+
+ingester:
+  lifecycler:
+    address: 127.0.0.1
+    ring:
+      kvstore:
+        store: inmemory
+      replication_factor: 1
+    final_sleep: 0s
+  trace_idle_period: 1s
+  max_block_bytes: 1
+  max_block_duration: 2s
+  complete_block_timeout: 20s
+  flush_check_period: 1s
+
+storage:
+  trace:
+    backend: local
+    local:
+      path: /var/tempo
+    pool:
+      max_workers: 10
+      queue_depth: 100
+    block:
+      version: vParquet4
+    blocklist_poll: 1s
+
+overrides:
+  defaults:
+    metrics_generator:
+      processors: [ local-blocks ]
+  user_configurable_overrides:
+    enabled: true
+    poll_interval: 10s
+    client:
+      backend: local
+      local:
+        path: /var/tempo/overrides

integration/e2e/query_range_test.go

@@ -7,16 +7,22 @@ import (
 	"io"
 	"net/http"
 	"net/url"
+	"strings"
 	"testing"
 	"time"
 
+	"github.com/gogo/protobuf/jsonpb"
+
 	"github.com/grafana/e2e"
 	"github.com/grafana/tempo/integration/util"
 	"github.com/grafana/tempo/pkg/tempopb"
 	"github.com/stretchr/testify/require"
 )
 
-const configQueryRange = "config-query-range.yaml"
+const (
+	configQueryRange          = "config-query-range.yaml"
+	configQueryRangeMaxSeries = "config-query-range-max-series.yaml"
+)
 
 // Set debugMode to true to print the response body
 var debugMode = false
@@ -65,6 +71,69 @@ sendLoop:
 	require.Equal(t, 400, res.StatusCode)
 }
 
+func TestQueryRangeMaxSeries(t *testing.T) {
+	s, err := e2e.NewScenario("tempo_e2e")
+	require.NoError(t, err)
+	defer s.Close()
+
+	require.NoError(t, util.CopyFileToSharedDir(s, configQueryRangeMaxSeries, "config.yaml"))
+	tempo := util.NewTempoAllInOne()
+	require.NoError(t, s.StartAndWaitReady(tempo))
+
+	jaegerClient, err := util.NewJaegerGRPCClient(tempo.Endpoint(14250))
+	require.NoError(t, err)
+	require.NotNil(t, jaegerClient)
+
+	ticker := time.NewTicker(500 * time.Millisecond)
+	defer ticker.Stop()
+	timer := time.NewTimer(5 * time.Second)
+	defer timer.Stop()
+sendLoop:
+	for {
+		select {
+		case <-ticker.C:
+			require.NoError(t, jaegerClient.EmitBatch(context.Background(), util.MakeThriftBatch()))
+		case <-timer.C:
+			break sendLoop
+		}
+	}
+
+	// Wait for traces to be flushed to blocks
+	require.NoError(t, tempo.WaitSumMetricsWithOptions(e2e.GreaterOrEqual(1), []string{"tempo_metrics_generator_processor_local_blocks_spans_total"}, e2e.WaitMissingMetrics))
+	require.NoError(t, tempo.WaitSumMetricsWithOptions(e2e.GreaterOrEqual(1), []string{"tempo_metrics_generator_processor_local_blocks_cut_blocks"}, e2e.WaitMissingMetrics))
+
+	query := "{} | rate() by (span:id)"
+	url := fmt.Sprintf(
+		"http://%s/api/metrics/query_range?q=%s&start=%d&end=%d&step=%s",
+		tempo.Endpoint(3200),
+		url.QueryEscape(query),
+		time.Now().Add(-5*time.Minute).UnixNano(),
+		time.Now().Add(time.Minute).UnixNano(),
+		"5s",
+	)
+
+	req, err := http.NewRequest(http.MethodGet, url, nil)
+	require.NoError(t, err)
+
+	res, err := http.DefaultClient.Do(req)
+	require.NoError(t, err)
+
+	// Read body and print it
+	body, err := io.ReadAll(res.Body)
+	require.NoError(t, err)
+	fmt.Println(string(body))
+
+	queryRangeRes := &tempopb.QueryRangeResponse{}
+	readBody := strings.NewReader(string(body))
+	err = new(jsonpb.Unmarshaler).Unmarshal(readBody, queryRangeRes)
+	require.NotNil(t, queryRangeRes)
+
+	// max series is 3 so we should get a partial response with 3 series
+	require.Equal(t, tempopb.PartialStatus_PARTIAL, queryRangeRes.GetStatus())
+	require.Equal(t, "Response exceeds maximum series of 3, a partial response is returned", queryRangeRes.GetMessage())
+	require.Equal(t, 3, len(queryRangeRes.GetSeries()))
+}
+
 func callQueryRange(t *testing.T, endpoint, query string, printBody bool) {
 	res := doRequest(t, endpoint, query)
 	require.Equal(t, http.StatusOK, res.StatusCode)

modules/frontend/combiner/metrics_query_range.go

@@ -1,6 +1,7 @@
 package combiner
 
 import (
+	"fmt"
 	"math"
 	"slices"
 	"sort"
@@ -14,8 +15,8 @@ import (
 var _ GRPCCombiner[*tempopb.QueryRangeResponse] = (*genericCombiner[*tempopb.QueryRangeResponse])(nil)
 
 // NewQueryRange returns a query range combiner.
-func NewQueryRange(req *tempopb.QueryRangeRequest) (Combiner, error) {
-	combiner, err := traceql.QueryRangeCombinerFor(req, traceql.AggregateModeFinal)
+func NewQueryRange(req *tempopb.QueryRangeRequest, maxSeries int) (Combiner, error) {
+	combiner, err := traceql.QueryRangeCombinerFor(req, traceql.AggregateModeFinal, maxSeries)
 	if err != nil {
 		return nil, err
 	}
@@ -45,6 +46,13 @@ func NewQueryRange(req *tempopb.QueryRangeRequest) (Combiner, error) {
 			if resp == nil {
 				resp = &tempopb.QueryRangeResponse{}
 			}
+			if maxSeries > 0 && len(resp.Series) >= maxSeries {
+				// Truncating the final response because even if we bail as soon as len(resp.Series) >= maxSeries
+				// it's possible that the last response pushed us over the max series limit.
+				resp.Series = resp.Series[:maxSeries]
+				resp.Status = tempopb.PartialStatus_PARTIAL
+				resp.Message = fmt.Sprintf("Response exceeds maximum series of %d, a partial response is returned", maxSeries)
+			}
 			sortResponse(resp)
 			attachExemplars(req, resp)
 
@@ -65,15 +73,18 @@ func NewQueryRange(req *tempopb.QueryRangeRequest) (Combiner, error) {
 
 			return diff, nil
 		},
+		quit: func(resp *tempopb.QueryRangeResponse) bool {
+			return combiner.MaxSeriesReached()
+		},
 	}
 
 	initHTTPCombiner(c, api.HeaderAcceptJSON)
 
 	return c, nil
 }
 
-func NewTypedQueryRange(req *tempopb.QueryRangeRequest) (GRPCCombiner[*tempopb.QueryRangeResponse], error) {
-	c, err := NewQueryRange(req)
+func NewTypedQueryRange(req *tempopb.QueryRangeRequest, maxSeries int) (GRPCCombiner[*tempopb.QueryRangeResponse], error) {
+	c, err := NewQueryRange(req, maxSeries)
 	if err != nil {
 		return nil, err
 	}

modules/frontend/combiner/metrics_query_range_test.go

@@ -514,6 +514,109 @@ func TestDiffExemplars(t *testing.T) {
 	}
 }
 
+func TestQueryRangemaxSeriesShouldQuit(t *testing.T) {
+	start := uint64(1100 * time.Second)
+	end := uint64(1300 * time.Second)
+	step := traceql.DefaultQueryRangeStep(start, end)
+
+	req := &tempopb.QueryRangeRequest{
+		Query: "{} | rate()",
+		Start: start,
+		End:   end,
+		Step:  step,
+	}
+
+	maxSeries := 4
+	queryRangeCombiner, err := NewQueryRange(req, maxSeries)
+	require.NoError(t, err)
+
+	// add 3 series, should not quit
+	resp := &tempopb.QueryRangeResponse{
+		Metrics: &tempopb.SearchMetrics{
+			InspectedTraces: 1,
+			InspectedBytes:  1,
+		},
+		Series: []*tempopb.TimeSeries{
+			{
+				PromLabels: "foo",
+				Labels: []v1.KeyValue{
+					{Key: "foo", Value: &v1.AnyValue{Value: &v1.AnyValue_StringValue{StringValue: "bar"}}},
+				},
+				Samples: []tempopb.Sample{
+					{
+						TimestampMs: 1200_000,
+						Value:       2,
+					},
+				},
+			},
+			{
+				PromLabels: "boo",
+				Labels: []v1.KeyValue{
+					{Key: "boo", Value: &v1.AnyValue{Value: &v1.AnyValue_StringValue{StringValue: "bar"}}},
+				},
+				Samples: []tempopb.Sample{
+					{
+						TimestampMs: 1200_000,
+						Value:       2,
+					},
+				},
+			},
+			{
+				PromLabels: "moo",
+				Labels: []v1.KeyValue{
+					{Key: "moo", Value: &v1.AnyValue{Value: &v1.AnyValue_StringValue{StringValue: "bar"}}},
+				},
+				Samples: []tempopb.Sample{
+					{
+						TimestampMs: 1200_000,
+						Value:       2,
+					},
+				},
+			},
+		},
+	}
+
+	queryRangeCombiner.AddResponse(toHTTPResponse(t, resp, 200))
+	require.False(t, queryRangeCombiner.ShouldQuit())
+
+	// add 4th & 5th series, should quit
+	secondResp := &tempopb.QueryRangeResponse{
+		Metrics: &tempopb.SearchMetrics{
+			InspectedTraces: 1,
+			InspectedBytes:  1,
+		},
+		Series: []*tempopb.TimeSeries{
+			{
+				PromLabels: "goo",
+				Labels: []v1.KeyValue{
+					{Key: "foo", Value: &v1.AnyValue{Value: &v1.AnyValue_StringValue{StringValue: "bar"}}},
+				},
+				Samples: []tempopb.Sample{
+					{
+						TimestampMs: 1200_000,
+						Value:       2,
+					},
+				},
+			},
+			{
+				PromLabels: "poo",
+				Labels: []v1.KeyValue{
+					{Key: "foo", Value: &v1.AnyValue{Value: &v1.AnyValue_StringValue{StringValue: "bar"}}},
+				},
+				Samples: []tempopb.Sample{
+					{
+						TimestampMs: 1200_000,
+						Value:       2,
+					},
+				},
+			},
+		},
+	}
+
+	queryRangeCombiner.AddResponse(toHTTPResponse(t, secondResp, 200))
+	require.True(t, queryRangeCombiner.ShouldQuit())
+}
+
 func BenchmarkDiffSeriesAndMarshal(b *testing.B) {
 	prev, curr := seriesWithTenPercentDiff()