vmsingle: return an error for the /status/metric_names_stats endpoints if the feature is not enabled with the -storage.trackMetricNamesStats flag

app/vmselect/netstorage/netstorage.go

@@ -1379,6 +1379,5 @@ func GetMetricNamesStats(qt *querytracer.Tracer, limit, le int, matchPattern str
 func ResetMetricNamesStats(qt *querytracer.Tracer) error {
 	qt = qt.NewChild("reset metric names usage stats")
 	defer qt.Done()
-	vmstorage.ResetMetricNamesStats(qt)
-	return nil
+	return vmstorage.ResetMetricNamesStats(qt)
 }

app/vmstorage/main.go

@@ -201,6 +201,9 @@ func DeleteSeries(qt *querytracer.Tracer, tfss []*storage.TagFilters, maxMetrics
 
 // GetMetricNamesStats returns metric names usage stats with give limit and lte predicate
 func GetMetricNamesStats(qt *querytracer.Tracer, limit, le int, matchPattern string) (storage.MetricNamesStatsResponse, error) {
+	if !*trackMetricNamesStats {
+		return storage.MetricNamesStatsResponse{}, fmt.Errorf("metrics usage feature must be enabled specifically using the `-storage.trackMetricNamesStats` flag")
+	}
 	WG.Add(1)
 	r := Storage.GetMetricNamesStats(qt, limit, le, matchPattern)
 	WG.Done()
@@ -208,10 +211,14 @@ func GetMetricNamesStats(qt *querytracer.Tracer, limit, le int, matchPattern str
 }
 
 // ResetMetricNamesStats resets state for metric names usage tracker
-func ResetMetricNamesStats(qt *querytracer.Tracer) {
+func ResetMetricNamesStats(qt *querytracer.Tracer) error {
+	if !*trackMetricNamesStats {
+		return fmt.Errorf("metrics usage feature must be enabled specifically using the `-storage.trackMetricNamesStats` flag")
+	}
 	WG.Add(1)
 	Storage.ResetMetricNamesStats(qt)
 	WG.Done()
+	return nil
 }
 
 // SearchMetricNames returns metric names for the given tfss on the given tr.

docs/victoriametrics/changelog/CHANGELOG.md

@@ -34,6 +34,7 @@ See also [LTS releases](https://docs.victoriametrics.com/lts-releases/).
 * BUGFIX: [vmsingle](https://docs.victoriametrics.com/single-server-victoriametrics/), `vminsert` in [VictoriaMetrics cluster](https://docs.victoriametrics.com/cluster-victoriametrics/) and [vmagent](https://docs.victoriametrics.com/vmagent/): support `identity` value in `Content-Encoding` HTTP header. See [this issue](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/8649).
 * BUGFIX: [vmsingle](https://docs.victoriametrics.com/single-server-victoriametrics/), `vminsert` in [VictoriaMetrics cluster](https://docs.victoriametrics.com/cluster-victoriametrics/) and [vmagent](https://docs.victoriametrics.com/vmagent/): fix timeseries with empty timestamp and value in Datadog sketches API. See [this issue](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/8649).
 * BUGFIX: [vmsingle](https://docs.victoriametrics.com/single-server-victoriametrics/), [vmagent](https://docs.victoriametrics.com/vmagent/), `vminsert` in [VictoriaMetrics cluster](https://docs.victoriametrics.com/cluster-victoriametrics/): restore write concurrency limiter for data ingestion. The limiter was unintentionally removed in [v1.115.0](https://github.com/VictoriaMetrics/VictoriaMetrics/releases/tag/v1.115.0) and potentially could lead to increased memory usage in certain scenarios. See [this issue](https://github.com/VictoriaMetrics/VictoriaMetrics/pull/8742).
+* BUGFIX: [vmsingle](https://docs.victoriametrics.com/single-server-victoriametrics/): return an error for the `/status/metric_names_stats` endpoints if the feature is not enabled with the `-storage.trackMetricNamesStats` flag.
 
 ## [v1.115.0](https://github.com/VictoriaMetrics/VictoriaMetrics/releases/tag/v1.115.0)