chore: add last seen info in err message

pkg/querier/querier.go

@@ -20,6 +20,7 @@ import (
 	"github.com/SigNoz/signoz/pkg/types/instrumentationtypes"
 	"github.com/SigNoz/signoz/pkg/types/metrictypes"
 	"github.com/SigNoz/signoz/pkg/types/telemetrytypes"
+	"github.com/dustin/go-humanize"
 	"golang.org/x/exp/maps"
 
 	qbtypes "github.com/SigNoz/signoz/pkg/types/querybuildertypes/querybuildertypesv5"
@@ -279,6 +280,7 @@ func (q *querier) QueryRange(ctx context.Context, orgID valuer.UUID, req *qbtype
 
 	queries := make(map[string]qbtypes.Query)
 	steps := make(map[string]qbtypes.Step)
+	missingMetrics := []string{}
 
 	for _, query := range req.CompositeQuery.Queries {
 		var queryName string
@@ -371,7 +373,6 @@ func (q *querier) QueryRange(ctx context.Context, orgID valuer.UUID, req *qbtype
 					}
 					q.logger.DebugContext(ctx, "fetched metric temporalities and types", "metric_temporality", metricTemporality, "metric_types", metricTypes)
 				}
-				missingMetrics := []string{}
 				for i := range spec.Aggregations {
 					if spec.Aggregations[i].MetricName != "" && spec.Aggregations[i].Temporality == metrictypes.Unknown {
 						if temp, ok := metricTemporality[spec.Aggregations[i].MetricName]; ok && temp != metrictypes.Unknown {
@@ -389,11 +390,6 @@ func (q *querier) QueryRange(ctx context.Context, orgID valuer.UUID, req *qbtype
 						}
 					}
 				}
-				if len(missingMetrics) == 1 {
-					return nil, errors.NewNotFoundf(errors.CodeNotFound, "no data found for the metric %s in the query time range", missingMetrics[0])
-				} else if len(missingMetrics) > 1 {
-					return nil, errors.NewNotFoundf(errors.CodeNotFound, "no data found for the following metrics in the query time range: %s", strings.Join(missingMetrics, ", "))
-				}
 				spec.ShiftBy = extractShiftFromBuilderQuery(spec)
 				timeRange := adjustTimeRangeForShift(spec, qbtypes.TimeRange{From: req.Start, To: req.End}, req.RequestType)
 				var bq *builderQuery[qbtypes.MetricAggregation]
@@ -412,6 +408,24 @@ func (q *querier) QueryRange(ctx context.Context, orgID valuer.UUID, req *qbtype
 			}
 		}
 	}
+	if len(missingMetrics) > 0 {
+		lastSeenInfo, _ := q.metadataStore.FetchLastSeenInfoMulti(ctx, missingMetrics...)
+		lastSeenStr := func(name string) string {
+			if ts, ok := lastSeenInfo[name]; ok && ts > 0 {
+				ago := humanize.RelTime(time.UnixMilli(ts), time.Now(), "ago", "from now")
+				return fmt.Sprintf("%s (last seen %s)", name, ago)
+			}
+			return name
+		}
+		if len(missingMetrics) == 1 {
+			return nil, errors.NewNotFoundf(errors.CodeNotFound, "no data found for the metric %s in the query time range", lastSeenStr(missingMetrics[0]))
+		}
+		parts := make([]string, len(missingMetrics))
+		for i, m := range missingMetrics {
+			parts[i] = lastSeenStr(m)
+		}
+		return nil, errors.NewNotFoundf(errors.CodeNotFound, "no data found for the following metrics in the query time range: %s", strings.Join(parts, ", "))
+	}
 	qbResp, qbErr := q.run(ctx, orgID, queries, req, steps, event)
 	if qbResp != nil {
 		qbResp.QBEvent = event

pkg/telemetrymetadata/metadata.go

@@ -1928,3 +1928,37 @@ func (t *telemetryMetaStore) GetFirstSeenFromMetricMetadata(ctx context.Context,
 
 	return result, nil
 }
+
+func (t *telemetryMetaStore) FetchLastSeenInfoMulti(ctx context.Context, metricNames ...string) (map[string]int64, error) {
+	sb := sqlbuilder.Select(
+		"metric_name",
+		"max(unix_milli)",
+	).
+		From(t.metricsDBName + "." + telemetrymetrics.TimeseriesV4TableName)
+	sb.Where(sb.In("metric_name", metricNames))
+	sb.GroupBy("metric_name")
+
+	query, args := sb.BuildWithFlavor(sqlbuilder.ClickHouse)
+
+	t.logger.DebugContext(ctx, "fetching metric last seen timestamp", "query", query, "args", args)
+
+	rows, err := t.telemetrystore.ClickhouseDB().Query(ctx, query, args...)
+	if err != nil {
+		return nil, errors.Wrapf(err, errors.TypeInternal, errors.CodeInternal, "failed to fetch metric last seen info")
+	}
+	defer rows.Close()
+
+	lastSeenInfo := make(map[string]int64)
+	for rows.Next() {
+		var metricName string
+		var unix_milli int64
+		if err := rows.Scan(&metricName, &unix_milli); err != nil {
+			return nil, errors.Wrapf(err, errors.TypeInternal, errors.CodeInternal, "failed to scan last seen info result")
+		}
+		lastSeenInfo[metricName] = unix_milli
+	}
+	if err := rows.Err(); err != nil {
+		return nil, errors.Wrapf(err, errors.TypeInternal, errors.CodeInternal, "error iterating over metrics temporality rows")
+	}
+	return lastSeenInfo, nil
+}

pkg/types/telemetrytypes/store.go

@@ -45,6 +45,8 @@ type MetadataStore interface {
 
 	// GetFirstSeenFromMetricMetadata gets the first seen timestamp for a metric metadata lookup key.
 	GetFirstSeenFromMetricMetadata(ctx context.Context, lookupKeys []MetricMetadataLookupKey) (map[MetricMetadataLookupKey]int64, error)
+
+	FetchLastSeenInfoMulti(ctx context.Context, metricNames ...string) (map[string]int64, error)
 }
 
 type MetricMetadataLookupKey struct {

pkg/types/telemetrytypes/telemetrytypestest/metadata_store.go

@@ -342,3 +342,7 @@ func (m *MockMetadataStore) SetFirstSeenFromMetricMetadata(firstSeenMap map[tele
 		m.LookupKeysMap[key] = value
 	}
 }
+
+func (m *MockMetadataStore) FetchLastSeenInfoMulti(ctx context.Context, metricNames ...string) (map[string]int64, error) {
+	return make(map[string]int64), nil
+}