diff --git a/internal/querynode/collection_replica.go b/internal/querynode/collection_replica.go
index 79f850f204..1c6dfc1613 100644
--- a/internal/querynode/collection_replica.go
+++ b/internal/querynode/collection_replica.go
@@ -141,6 +141,7 @@ func (colReplica *collectionReplica) queryUnlock() {
 	colReplica.queryMu.Unlock()
 }
 
+// queryRLock guards query and delete segment operations
 func (colReplica *collectionReplica) queryRLock() {
 	colReplica.queryMu.RLock()
 }