diff --git a/session-dealer/mysql/config.go b/session-dealer/mysql/config.go
index a12eeed..6215386 100644
--- a/session-dealer/mysql/config.go
+++ b/session-dealer/mysql/config.go
@@ -16,7 +16,8 @@ var (
 	strictMode bool
 	adminUser string
 	adminPasswd string
-
+	// MaxMysqlPacketLen is the max packet payload length.
+	MaxMysqlPacketLen int
 	coverRangePool = NewCoveragePool()
 	localStmtCache = util.NewSliceBufferPool("statement cache", MaxMysqlPacketLen)
 
@@ -27,6 +28,7 @@ func init() {
 	flag.BoolVar(&strictMode,"strict_mode", false, "strict mode. Default is false")
 	flag.StringVar(&adminUser,"admin_user", "", "admin user name. When set strict mode, must set admin user to query session info")
 	flag.StringVar(&adminPasswd,"admin_passwd", "", "admin user passwd. When use strict mode, must set admin user to query session info")
+	flag.IntVar(&MaxMysqlPacketLen, "max_packet_length", 128 * 1024, "max mysql packet length. Default is 128 * 1024")
 }
 
 func CheckParams()  {
diff --git a/session-dealer/mysql/const.go b/session-dealer/mysql/const.go
index adc4780..6bd5a29 100644
--- a/session-dealer/mysql/const.go
+++ b/session-dealer/mysql/const.go
@@ -91,13 +91,6 @@ const (
 	GlobalStatusTable = "GLOBAL_STATUS"
 )
 
-
-// Identifier length limitations.
-const (
-	// MaxMysqlPacketLen is the max packet payload length.
-	MaxMysqlPacketLen = 128 * 1024
-)
-
 const (
 	millSecondUnit = int64(time.Millisecond)
 )