fix(ha_tracker): track when there is a change during merge of Replica…

…Desc Components (#10185)

* fix(ha_tracker): track when there is a change during merge of ReplicaDesc Components

Signed-off-by: Nikos Angelopoulos <nikolaos.angelopoulos@grafana.com>

* update changelog

Signed-off-by: Nikos Angelopoulos <nikolaos.angelopoulos@grafana.com>

---------

Signed-off-by: Nikos Angelopoulos <nikolaos.angelopoulos@grafana.com>

CHANGELOG.md

@@ -123,6 +123,7 @@
 * [BUGFIX] Querier: Fix stddev+stdvar aggregations to treat Infinity consistently. #9844
 * [BUGFIX] Ingester: Chunks could have one unnecessary zero byte at the end. #9844
 * [BUGFIX] OTLP receiver: Preserve colons and combine multiple consecutive underscores into one when generating metric names in suffix adding mode (`-distributor.otel-metric-suffixes-enabled`). #10075
+* [BUGFIX] Distributor: Use a boolean to track changes while merging the ReplicaDesc components, rather than comparing the objects directly. #10185
 
 ### Mixin
 

pkg/distributor/ha_tracker.go

@@ -82,27 +82,32 @@ func (r *ReplicaDesc) mergeWithTime(mergeable memberlist.Mergeable) (memberlist.
 		return nil, nil
 	}
 
+	changed := false
 	if other.Replica == r.Replica {
 		// Keeping the one with the most recent receivedAt timestamp
 		if other.ReceivedAt > r.ReceivedAt {
 			*r = *other
+			changed = true
 		} else if r.ReceivedAt == other.ReceivedAt && r.DeletedAt == 0 && other.DeletedAt != 0 {
 			*r = *other
+			changed = true
 		}
 	} else {
 		// keep the most recent ElectedAt to reach consistency
 		if other.ElectedAt > r.ElectedAt {
 			*r = *other
+			changed = true
 		} else if other.ElectedAt == r.ElectedAt {
 			// if the timestamps are equal we compare ReceivedAt
 			if other.ReceivedAt > r.ReceivedAt {
 				*r = *other
+				changed = true
 			}
 		}
 	}
 
 	// No changes
-	if *r != *other {
+	if !changed {
 		return nil, nil
 	}
 

pkg/distributor/ha_tracker_test.go

@@ -223,6 +223,13 @@ func TestReplicaDescMerge(t *testing.T) {
 			}(),
 			expectedChange: nil,
 		},
+		{
+			name:           "Merge should return no change when replica is the same",
+			rDesc1:         firstReplica(),
+			rDesc2:         firstReplica(),
+			expectedRDesc:  firstReplica(),
+			expectedChange: nil,
+		},
 	}
 
 	for _, tt := range testsMerge {