diff --git a/internal/querynode/collection_replica.go b/internal/querynode/collection_replica.go
index 89a8a22ebb..c873f440ee 100644
--- a/internal/querynode/collection_replica.go
+++ b/internal/querynode/collection_replica.go
@@ -55,6 +55,7 @@ type ReplicaInterface interface {
 	hasCollection(collectionID UniqueID) bool
 	// getCollectionNum returns num of collections in collectionReplica
 	getCollectionNum() int
+	// getPartitionIDs returns partition ids of collection
 	getPartitionIDs(collectionID UniqueID) ([]UniqueID, error)
 	getVecFieldIDsByCollectionID(collectionID UniqueID) ([]FieldID, error)
 	getPKFieldIDByCollectionID(collectionID UniqueID) (FieldID, error)