diff --git a/model/query_piece.go b/model/query_piece.go
index 6f39677..e0a71dd 100644
--- a/model/query_piece.go
+++ b/model/query_piece.go
@@ -3,14 +3,14 @@ package model
 import (
 	"bytes"
 
-	"encoding/json"
-	// "github.com/json-iterator/go"
+	// "encoding/json"
+	"github.com/json-iterator/go"
 	"time"
 
 	"github.com/pingcap/tidb/util/hack"
 )
 
-// var json = jsoniter.ConfigCompatibleWithStandardLibrary
+var json = jsoniter.ConfigCompatibleWithStandardLibrary
 
 type QueryPiece interface {
 	String() *string