diff --git a/internal/rootcoord/meta_table.go b/internal/rootcoord/meta_table.go
index 6e6246cf3d..b775386cc3 100644
--- a/internal/rootcoord/meta_table.go
+++ b/internal/rootcoord/meta_table.go
@@ -1283,6 +1283,7 @@ func (mt *MetaTable) AlterAlias(collectionAlias string, collectionName string, t
 	return nil
 }
 
+// IsAlias returns true if specific `collectionAlias` is an alias of collection.
 func (mt *MetaTable) IsAlias(collectionAlias string) bool {
 	mt.ddLock.RLock()
 	defer mt.ddLock.RUnlock()