diff --git a/internal/proxy/impl.go b/internal/proxy/impl.go
index 67c4b57b84..538de821e8 100644
--- a/internal/proxy/impl.go
+++ b/internal/proxy/impl.go
@@ -1557,6 +1557,7 @@ func (node *Proxy) Search(ctx context.Context, request *milvuspb.SearchRequest)
 	return qt.result, nil
 }
 
+// Flush notify data nodes to persist the data of collection.
 func (node *Proxy) Flush(ctx context.Context, request *milvuspb.FlushRequest) (*milvuspb.FlushResponse, error) {
 	resp := &milvuspb.FlushResponse{
 		Status: &commonpb.Status{