diff --git a/internal/querynode/flow_graph_filter_dm_node.go b/internal/querynode/flow_graph_filter_dm_node.go
index 52e736a680..44a9f55e34 100644
--- a/internal/querynode/flow_graph_filter_dm_node.go
+++ b/internal/querynode/flow_graph_filter_dm_node.go
@@ -29,6 +29,7 @@ import (
 	"github.com/milvus-io/milvus/internal/util/trace"
 )
 
+// filterDmNode is one of the nodes in query node flow graph
 type filterDmNode struct {
 	baseNode
 	loadType     loadType // load collection or load partition