diff --git a/docs/developer_guides/chap04_message_stream.md b/docs/developer_guides/chap04_message_stream.md
index a63396e3ec..c6fdf17256 100644
--- a/docs/developer_guides/chap04_message_stream.md
+++ b/docs/developer_guides/chap04_message_stream.md
@@ -121,6 +121,7 @@ const (
 	MsgType_RemoveQueryChannels     MsgType = 511
 	// DATA SERVICE
 	MsgType_SegmentInfo MsgType = 600
+	MsgType_SystemInfo  MsgType = 601
 	// SYSTEM CONTROL
 	MsgType_TimeTick          MsgType = 1200
 	MsgType_QueryNodeStats    MsgType = 1201