diff --git a/internal/querynode/collection_replica.go b/internal/querynode/collection_replica.go
index daef6731f01b8127ec5c558d6a564bb300bdaf59..79f850f204d5d872f87e49d07b5512c063d593f8 100644
--- a/internal/querynode/collection_replica.go
+++ b/internal/querynode/collection_replica.go
@@ -136,6 +136,7 @@ func (colReplica *collectionReplica) queryLock() {
 	colReplica.queryMu.Lock()
 }
 
+// queryUnlock guards query and delete segment operations
 func (colReplica *collectionReplica) queryUnlock() {
 	colReplica.queryMu.Unlock()
 }