diff --git a/internal/querynode/flow_graph_delete_node.go b/internal/querynode/flow_graph_delete_node.go
index 786a411f80..ae9d9769ed 100644
--- a/internal/querynode/flow_graph_delete_node.go
+++ b/internal/querynode/flow_graph_delete_node.go
@@ -21,6 +21,7 @@ func (dNode *deleteNode) Name() string {
 	return "dNode"
 }
 
+// Operate handles input messages, do delete operations
 func (dNode *deleteNode) Operate(in []flowgraph.Msg) []flowgraph.Msg {
 	if len(in) != 1 {
 		log.Error("Invalid operate message input in deleteNode", zap.Int("input length", len(in)))