Fix a bug in MetricsForLabelMatchersStream (#4745)

Signed-off-by: 🌲 Harry 🌊 John 🏔 <[email protected]>

Author: harry671003

CHANGELOG.md

@@ -40,6 +40,7 @@
 * [BUGFIX] Distributor: Fix a memory leak in distributor due to the cluster label. #4739
 * [ENHANCEMENT] Compactor: uploading blocks no compaction marks to the global location and introduce a new metric #4729
   * `cortex_bucket_blocks_marked_for_no_compaction_count`: Total number of blocks marked for no compaction in the bucket.
+* [ENHANCEMENT] Querier: Reduce the number of series that are kept in memory while streaming from ingesters. #4745
 
 ## 1.11.0 2021-11-25
 

pkg/cortexpb/compat.go

@@ -102,6 +102,12 @@ func FromLabelAdaptersToMetric(ls []LabelAdapter) model.Metric {
 	return util.LabelsToMetric(FromLabelAdaptersToLabels(ls))
 }
 
+// FromLabelAdaptersToMetric converts []LabelAdapter to a model.Metric with copy.
+// Don't do this on any performance sensitive paths.
+func FromLabelAdaptersToMetricWithCopy(ls []LabelAdapter) model.Metric {
+	return util.LabelsToMetric(FromLabelAdaptersToLabelsWithCopy(ls))
+}
+
 // FromMetricsToLabelAdapters converts model.Metric to []LabelAdapter.
 // Don't do this on any performance sensitive paths.
 // The result is sorted.

pkg/distributor/distributor.go

@@ -1058,7 +1058,7 @@ func (d *Distributor) MetricsForLabelMatchersStream(ctx context.Context, from, t
 				}
 
 				for _, metric := range resp.Metric {
-					m := cortexpb.FromLabelAdaptersToMetric(metric.Labels)
+					m := cortexpb.FromLabelAdaptersToMetricWithCopy(metric.Labels)
 
 					if err := queryLimiter.AddSeries(cortexpb.FromMetricsToLabelAdapters(m)); err != nil {
 						return nil, err