From 9c37399a32bd5ed919e7dcd05af796bf18de9205 Mon Sep 17 00:00:00 2001
From: Weizhen Wang <wangweizhen@pingcap.com>
Date: Thu, 23 Jan 2025 09:52:56 +0800
Subject: [PATCH] types: avoid slicegrow in the FieldName.String() (#59136)

close pingcap/tidb#59135
---
 pkg/types/field_name.go | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/pkg/types/field_name.go b/pkg/types/field_name.go
index 74f90607a7a13..dcd1fef048de3 100644
--- a/pkg/types/field_name.go
+++ b/pkg/types/field_name.go
@@ -15,7 +15,7 @@
 package types
 
 import (
-	"strings"
+	"bytes"
 
 	"github.com/pingcap/tidb/pkg/parser/ast"
 	"github.com/pingcap/tidb/pkg/util/size"
@@ -43,10 +43,11 @@ const emptyName = "EMPTY_NAME"
 
 // String implements Stringer interface.
 func (name *FieldName) String() string {
-	builder := strings.Builder{}
 	if name.Hidden {
 		return emptyName
 	}
+	bs := make([]byte, 0, len(name.DBName.L)+1+len(name.TblName.L)+1+len(name.ColName.L))
+	builder := bytes.NewBuffer(bs)
 	if name.DBName.L != "" {
 		builder.WriteString(name.DBName.L + ".")
 	}