diff --git a/internal/util/mqclient/rmq_id.go b/internal/util/mqclient/rmq_id.go
index 0857fbe1ed..b21690c7b9 100644
--- a/internal/util/mqclient/rmq_id.go
+++ b/internal/util/mqclient/rmq_id.go
@@ -17,6 +17,7 @@ import (
 	"github.com/milvus-io/milvus/internal/util/rocksmq/server/rocksmq"
 )
 
+// rmqID wraps message ID for rocksmq
 type rmqID struct {
 	messageID rocksmq.UniqueID
 }