diff --git a/internal/distributed/querynode/service.go b/internal/distributed/querynode/service.go
index 75edb9b2e4..4f232f0b59 100644
--- a/internal/distributed/querynode/service.go
+++ b/internal/distributed/querynode/service.go
@@ -259,6 +259,7 @@ func (s *Server) Stop() error {
 	return nil
 }
 
+// SetRootCoord sets the RootCoord's client for QueryNode component.
 func (s *Server) SetRootCoord(rootCoord types.RootCoord) error {
 	return s.querynode.SetRootCoord(rootCoord)
 }