diff --git a/internal/querynode/index_loader.go b/internal/querynode/index_loader.go
index d75b782161..5d58aeaf7c 100644
--- a/internal/querynode/index_loader.go
+++ b/internal/querynode/index_loader.go
@@ -34,6 +34,7 @@ import (
 
 type indexParam = map[string]string
 
+// indexLoader is in charge of loading index in query node
 type indexLoader struct {
 	replica ReplicaInterface