diff --git a/common/config.go b/common/config.go
index 8f2b451d528eeb7235148667df805669760de7b5..a8a78bba1ce34c8f5e4074ed0bab74814b279dcf 100644
--- a/common/config.go
+++ b/common/config.go
@@ -257,7 +257,7 @@ func parseDSN(odbc string, d *dsn) *dsn {
 
 	if d != nil {
 		// 原来有个判断，后来判断条件被删除了就导致第一次addr无论如何都会被修改。所以这边先注释掉
-		//addr = d.Addr
+		// addr = d.Addr
 		user = d.User
 		password = d.Password
 		schema = d.Schema
@@ -273,27 +273,24 @@ func parseDSN(odbc string, d *dsn) *dsn {
 	var userInfo, hostInfo, query string
 
 	// DSN 格式匹配
-	// userInfo@hostInfo/database
-	if res := regexp.MustCompile( `^(.*)@(.*?)/(.*?)($|\?)(.*)`).FindStringSubmatch(odbc); len(res)  > 5 {
+	if res := regexp.MustCompile(`^(.*)@(.*?)/(.*?)($|\?)(.*)`).FindStringSubmatch(odbc); len(res) > 5 {
+		// userInfo@hostInfo/database
 		userInfo = res[1]
 		hostInfo = res[2]
 		schema = res[3]
 		query = res[5]
-
-	// hostInfo/database
 	} else if res := regexp.MustCompile(`^(.*)/(.*?)($|\?)(.*)`).FindStringSubmatch(odbc); len(res) > 4 {
+		// hostInfo/database
 		hostInfo = res[1]
 		schema = res[2]
 		query = res[4]
-
-	// userInfo@hostInfo
 	} else if res := regexp.MustCompile(`^(.*)@(.*?)($|\?)(.*)`).FindStringSubmatch(odbc); len(res) > 4 {
+		// userInfo@hostInfo
 		userInfo = res[1]
 		hostInfo = res[2]
 		query = res[4]
-		
-	// hostInfo
 	} else {
+		// hostInfo
 		hostInfo = odbc
 	}
 
@@ -301,7 +298,7 @@ func parseDSN(odbc string, d *dsn) *dsn {
 	if userInfo != "" {
 		user = strings.Split(userInfo, ":")[0]
 		// 防止密码中含有与用户名相同的字符, 所以用正则替换, 剩下的就是密码
-		password = strings.TrimLeft(regexp.MustCompile("^" + user).ReplaceAllString(userInfo, ""), ":")
+		password = strings.TrimLeft(regexp.MustCompile("^"+user).ReplaceAllString(userInfo, ""), ":")
 	}
 
 	// 解析主机信息
@@ -310,13 +307,13 @@ func parseDSN(odbc string, d *dsn) *dsn {
 	if host == "" {
 		host = "127.0.0.1"
 	}
-	if port == ""{
+	if port == "" {
 		port = "3306"
 	}
 	addr = host + ":" + port
 
 	// 解析查询字符串
-	if (query != "") {
+	if query != "" {
 		params := strings.Split(query, "&")
 		for _, f := range params {
 			attr := strings.Split(f, "=")
diff --git a/vendor/github.com/pingcap/parser/ast/ast.go b/vendor/github.com/pingcap/parser/ast/ast.go
index c80a7ad8bc586dfc292292fc0d796da1d1612d72..c13e592c2948c4d3832aed5c62ddb1308ed4125e 100644
--- a/vendor/github.com/pingcap/parser/ast/ast.go
+++ b/vendor/github.com/pingcap/parser/ast/ast.go
@@ -17,7 +17,6 @@ package ast
 
 import (
 	"io"
-	"strings"
 
 	"github.com/pingcap/parser/model"
 	"github.com/pingcap/parser/types"
@@ -27,7 +26,7 @@ import (
 // Interfaces embed Node should have 'Node' name suffix.
 type Node interface {
 	// Restore returns the sql text from ast tree
-	Restore(sb *strings.Builder) error
+	Restore(ctx *RestoreCtx) error
 	// Accept accepts Visitor to visit itself.
 	// The returned node should replace original node.
 	// ok returns false to stop visiting.
diff --git a/vendor/github.com/pingcap/parser/ast/ddl.go b/vendor/github.com/pingcap/parser/ast/ddl.go
index e4ac1f16145c289c84bf1dccc1da69159e99554e..4ce72d1097339d05751108714395032c9384b867 100644
--- a/vendor/github.com/pingcap/parser/ast/ddl.go
+++ b/vendor/github.com/pingcap/parser/ast/ddl.go
@@ -14,8 +14,6 @@
 package ast
 
 import (
-	"strings"
-
 	"github.com/pingcap/errors"
 	"github.com/pingcap/parser/auth"
 	"github.com/pingcap/parser/model"
@@ -65,15 +63,17 @@ type DatabaseOption struct {
 	Value string
 }
 
-// Restore implements Recoverable interface.
-func (n *DatabaseOption) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *DatabaseOption) Restore(ctx *RestoreCtx) error {
 	switch n.Tp {
 	case DatabaseOptionCharset:
-		sb.WriteString("CHARACTER SET = ")
-		sb.WriteString(n.Value)
+		ctx.WriteKeyWord("CHARACTER SET")
+		ctx.WritePlain(" = ")
+		ctx.WritePlain(n.Value)
 	case DatabaseOptionCollate:
-		sb.WriteString("COLLATE = ")
-		sb.WriteString(n.Value)
+		ctx.WriteKeyWord("COLLATE")
+		ctx.WritePlain(" = ")
+		ctx.WritePlain(n.Value)
 	default:
 		return errors.Errorf("invalid DatabaseOptionType: %d", n.Tp)
 	}
@@ -90,16 +90,16 @@ type CreateDatabaseStmt struct {
 	Options     []*DatabaseOption
 }
 
-// Restore implements Recoverable interface.
-func (n *CreateDatabaseStmt) Restore(sb *strings.Builder) error {
-	sb.WriteString("CREATE DATABASE ")
+// Restore implements Node interface.
+func (n *CreateDatabaseStmt) Restore(ctx *RestoreCtx) error {
+	ctx.WriteKeyWord("CREATE DATABASE ")
 	if n.IfNotExists {
-		sb.WriteString("IF NOT EXISTS ")
+		ctx.WriteKeyWord("IF NOT EXISTS ")
 	}
-	WriteName(sb, n.Name)
+	ctx.WriteName(n.Name)
 	for _, option := range n.Options {
-		sb.WriteString(" ")
-		err := option.Restore(sb)
+		ctx.WritePlain(" ")
+		err := option.Restore(ctx)
 		if err != nil {
 			return errors.Trace(err)
 		}
@@ -126,13 +126,13 @@ type DropDatabaseStmt struct {
 	Name     string
 }
 
-// Restore implements Recoverable interface.
-func (n *DropDatabaseStmt) Restore(sb *strings.Builder) error {
-	sb.WriteString("DROP DATABASE ")
+// Restore implements Node interface.
+func (n *DropDatabaseStmt) Restore(ctx *RestoreCtx) error {
+	ctx.WriteKeyWord("DROP DATABASE ")
 	if n.IfExists {
-		sb.WriteString("IF EXISTS ")
+		ctx.WriteKeyWord("IF EXISTS ")
 	}
-	WriteName(sb, n.Name)
+	ctx.WriteName(n.Name)
 	return nil
 }
 
@@ -154,8 +154,8 @@ type IndexColName struct {
 	Length int
 }
 
-// Restore implements Recoverable interface.
-func (n *IndexColName) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *IndexColName) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -185,8 +185,8 @@ type ReferenceDef struct {
 	OnUpdate      *OnUpdateOpt
 }
 
-// Restore implements Recoverable interface.
-func (n *ReferenceDef) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *ReferenceDef) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -255,8 +255,8 @@ type OnDeleteOpt struct {
 	ReferOpt ReferOptionType
 }
 
-// Restore implements Recoverable interface.
-func (n *OnDeleteOpt) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *OnDeleteOpt) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -276,8 +276,8 @@ type OnUpdateOpt struct {
 	ReferOpt ReferOptionType
 }
 
-// Restore implements Recoverable interface.
-func (n *OnUpdateOpt) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *OnUpdateOpt) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -325,8 +325,8 @@ type ColumnOption struct {
 	Refer *ReferenceDef
 }
 
-// Restore implements Recoverable interface.
-func (n *ColumnOption) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *ColumnOption) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -361,8 +361,8 @@ type IndexOption struct {
 	Comment      string
 }
 
-// Restore implements Recoverable interface.
-func (n *IndexOption) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *IndexOption) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -406,8 +406,8 @@ type Constraint struct {
 	Option *IndexOption // Index Options
 }
 
-// Restore implements Recoverable interface.
-func (n *Constraint) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *Constraint) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -451,8 +451,8 @@ type ColumnDef struct {
 	Options []*ColumnOption
 }
 
-// Restore implements Recoverable interface.
-func (n *ColumnDef) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *ColumnDef) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -494,8 +494,8 @@ type CreateTableStmt struct {
 	Select      ResultSetNode
 }
 
-// Restore implements Recoverable interface.
-func (n *CreateTableStmt) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *CreateTableStmt) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -553,8 +553,8 @@ type DropTableStmt struct {
 	IsView   bool
 }
 
-// Restore implements Recoverable interface.
-func (n *DropTableStmt) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *DropTableStmt) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -588,8 +588,8 @@ type RenameTableStmt struct {
 	TableToTables []*TableToTable
 }
 
-// Restore implements Recoverable interface.
-func (n *RenameTableStmt) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *RenameTableStmt) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -629,8 +629,8 @@ type TableToTable struct {
 	NewTable *TableName
 }
 
-// Restore implements Recoverable interface.
-func (n *TableToTable) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *TableToTable) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -669,8 +669,8 @@ type CreateViewStmt struct {
 	CheckOption model.ViewCheckOption
 }
 
-// Restore implements Recoverable interface.
-func (n *CreateViewStmt) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *CreateViewStmt) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -706,8 +706,8 @@ type CreateIndexStmt struct {
 	IndexOption   *IndexOption
 }
 
-// Restore implements Recoverable interface.
-func (n *CreateIndexStmt) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *CreateIndexStmt) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -750,8 +750,8 @@ type DropIndexStmt struct {
 	Table     *TableName
 }
 
-// Restore implements Recoverable interface.
-func (n *DropIndexStmt) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *DropIndexStmt) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -843,8 +843,8 @@ type ColumnPosition struct {
 	RelativeColumn *ColumnName
 }
 
-// Restore implements Recoverable interface.
-func (n *ColumnPosition) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *ColumnPosition) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -925,8 +925,8 @@ type AlterTableSpec struct {
 	Num             uint64
 }
 
-// Restore implements Recoverable interface.
-func (n *AlterTableSpec) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *AlterTableSpec) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -984,8 +984,8 @@ type AlterTableStmt struct {
 	Specs []*AlterTableSpec
 }
 
-// Restore implements Recoverable interface.
-func (n *AlterTableStmt) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *AlterTableStmt) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -1019,8 +1019,8 @@ type TruncateTableStmt struct {
 	Table *TableName
 }
 
-// Restore implements Recoverable interface.
-func (n *TruncateTableStmt) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *TruncateTableStmt) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
diff --git a/vendor/github.com/pingcap/parser/ast/dml.go b/vendor/github.com/pingcap/parser/ast/dml.go
index 088eb74446a5935dcf2afb905601ec413d3dfe0b..504b6270f32a58fd2dbb71e88127ab46209b0b12 100644
--- a/vendor/github.com/pingcap/parser/ast/dml.go
+++ b/vendor/github.com/pingcap/parser/ast/dml.go
@@ -14,8 +14,6 @@
 package ast
 
 import (
-	"strings"
-
 	"github.com/pingcap/errors"
 	"github.com/pingcap/parser/auth"
 	"github.com/pingcap/parser/model"
@@ -85,8 +83,8 @@ type Join struct {
 	StraightJoin bool
 }
 
-// Restore implements Recoverable interface.
-func (n *Join) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *Join) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -133,16 +131,16 @@ type TableName struct {
 	IndexHints []*IndexHint
 }
 
-// Restore implements Recoverable interface.
-func (n *TableName) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *TableName) Restore(ctx *RestoreCtx) error {
 	if n.Schema.String() != "" {
-		WriteName(sb, n.Schema.String())
-		sb.WriteString(".")
+		ctx.WriteName(n.Schema.String())
+		ctx.WritePlain(".")
 	}
-	WriteName(sb, n.Name.String())
+	ctx.WriteName(n.Name.String())
 	for _, value := range n.IndexHints {
-		sb.WriteString(" ")
-		if err := value.Restore(sb); err != nil {
+		ctx.WritePlain(" ")
+		if err := value.Restore(ctx); err != nil {
 			return errors.Annotate(err, "An error occurred while splicing IndexHints")
 		}
 	}
@@ -178,7 +176,7 @@ type IndexHint struct {
 }
 
 // IndexHint Restore (The const field uses switch to facilitate understanding)
-func (n *IndexHint) Restore(sb *strings.Builder) error {
+func (n *IndexHint) Restore(ctx *RestoreCtx) error {
 	indexHintType := ""
 	switch n.HintType {
 	case 1:
@@ -204,17 +202,16 @@ func (n *IndexHint) Restore(sb *strings.Builder) error {
 	default: // Prevent accidents
 		return errors.New("IndexHintScope has an error while matching")
 	}
-
-	sb.WriteString(indexHintType)
-	sb.WriteString(indexHintScope)
-	sb.WriteString(" (")
+	ctx.WriteKeyWord(indexHintType)
+	ctx.WriteKeyWord(indexHintScope)
+	ctx.WritePlain(" (")
 	for i, value := range n.IndexNames {
 		if i > 0 {
-			sb.WriteString(", ")
+			ctx.WritePlain(", ")
 		}
-		WriteName(sb, value.O)
+		ctx.WriteName(value.O)
 	}
-	sb.WriteString(")")
+	ctx.WritePlain(")")
 
 	return nil
 }
@@ -235,8 +232,8 @@ type DeleteTableList struct {
 	Tables []*TableName
 }
 
-// Restore implements Recoverable interface.
-func (n *DeleteTableList) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *DeleteTableList) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -266,8 +263,8 @@ type OnCondition struct {
 	Expr ExprNode
 }
 
-// Restore implements Recoverable interface.
-func (n *OnCondition) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *OnCondition) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -298,8 +295,8 @@ type TableSource struct {
 	AsName model.CIStr
 }
 
-// Restore implements Recoverable interface.
-func (n *TableSource) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *TableSource) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -349,8 +346,8 @@ type WildCardField struct {
 	Schema model.CIStr
 }
 
-// Restore implements Recoverable interface.
-func (n *WildCardField) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *WildCardField) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -384,8 +381,8 @@ type SelectField struct {
 	Auxiliary bool
 }
 
-// Restore implements Recoverable interface.
-func (n *SelectField) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *SelectField) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -413,8 +410,8 @@ type FieldList struct {
 	Fields []*SelectField
 }
 
-// Restore implements Recoverable interface.
-func (n *FieldList) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *FieldList) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -442,8 +439,8 @@ type TableRefsClause struct {
 	TableRefs *Join
 }
 
-// Restore implements Recoverable interface.
-func (n *TableRefsClause) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *TableRefsClause) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -470,8 +467,8 @@ type ByItem struct {
 	Desc bool
 }
 
-// Restore implements Recoverable interface.
-func (n *ByItem) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *ByItem) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -496,8 +493,8 @@ type GroupByClause struct {
 	Items []*ByItem
 }
 
-// Restore implements Recoverable interface.
-func (n *GroupByClause) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *GroupByClause) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -524,8 +521,8 @@ type HavingClause struct {
 	Expr ExprNode
 }
 
-// Restore implements Recoverable interface.
-func (n *HavingClause) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *HavingClause) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -551,8 +548,8 @@ type OrderByClause struct {
 	ForUnion bool
 }
 
-// Restore implements Recoverable interface.
-func (n *OrderByClause) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *OrderByClause) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -609,8 +606,8 @@ type SelectStmt struct {
 	IsInBraces bool
 }
 
-// Restore implements Recoverable interface.
-func (n *SelectStmt) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *SelectStmt) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -708,8 +705,8 @@ type UnionSelectList struct {
 	Selects []*SelectStmt
 }
 
-// Restore implements Recoverable interface.
-func (n *UnionSelectList) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *UnionSelectList) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -741,8 +738,8 @@ type UnionStmt struct {
 	Limit      *Limit
 }
 
-// Restore implements Recoverable interface.
-func (n *UnionStmt) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *UnionStmt) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -786,8 +783,8 @@ type Assignment struct {
 	Expr ExprNode
 }
 
-// Restore implements Recoverable interface.
-func (n *Assignment) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *Assignment) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -825,8 +822,8 @@ type LoadDataStmt struct {
 	IgnoreLines uint64
 }
 
-// Restore implements Recoverable interface.
-func (n *LoadDataStmt) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *LoadDataStmt) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -883,8 +880,8 @@ type InsertStmt struct {
 	Select      ResultSetNode
 }
 
-// Restore implements Recoverable interface.
-func (n *InsertStmt) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *InsertStmt) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -964,8 +961,8 @@ type DeleteStmt struct {
 	TableHints []*TableOptimizerHint
 }
 
-// Restore implements Recoverable interface.
-func (n *DeleteStmt) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *DeleteStmt) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -1029,8 +1026,8 @@ type UpdateStmt struct {
 	TableHints    []*TableOptimizerHint
 }
 
-// Restore implements Recoverable interface.
-func (n *UpdateStmt) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *UpdateStmt) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -1085,8 +1082,8 @@ type Limit struct {
 	Offset ExprNode
 }
 
-// Restore implements Recoverable interface.
-func (n *Limit) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *Limit) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -1170,8 +1167,8 @@ type ShowStmt struct {
 	Where       ExprNode
 }
 
-// Restore implements Recoverable interface.
-func (n *ShowStmt) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *ShowStmt) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -1235,8 +1232,8 @@ type WindowSpec struct {
 	Frame       *FrameClause
 }
 
-// Restore implements Recoverable interface.
-func (n *WindowSpec) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *WindowSpec) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -1278,8 +1275,8 @@ type PartitionByClause struct {
 	Items []*ByItem
 }
 
-// Restore implements Recoverable interface.
-func (n *PartitionByClause) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *PartitionByClause) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -1319,8 +1316,8 @@ type FrameClause struct {
 	Extent FrameExtent
 }
 
-// Restore implements Recoverable interface.
-func (n *FrameClause) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *FrameClause) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -1372,8 +1369,8 @@ type FrameBound struct {
 	Unit ExprNode
 }
 
-// Restore implements Recoverable interface.
-func (n *FrameBound) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *FrameBound) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
diff --git a/vendor/github.com/pingcap/parser/ast/expressions.go b/vendor/github.com/pingcap/parser/ast/expressions.go
index 4e7224b249ee26a3c3875fc9d5539172004660e3..dd0302a18ee2370201a638086ba12ba290c14dd2 100644
--- a/vendor/github.com/pingcap/parser/ast/expressions.go
+++ b/vendor/github.com/pingcap/parser/ast/expressions.go
@@ -79,9 +79,24 @@ type BetweenExpr struct {
 	Not bool
 }
 
-// Restore implements Recoverable interface.
-func (n *BetweenExpr) Restore(sb *strings.Builder) error {
-	return errors.New("Not implemented")
+// Restore implements Node interface.
+func (n *BetweenExpr) Restore(ctx *RestoreCtx) error {
+	if err := n.Expr.Restore(ctx); err != nil {
+		return errors.Annotate(err, "An error occurred while restore BetweenExpr.Expr")
+	}
+	if n.Not {
+		ctx.WriteKeyWord(" NOT BETWEEN ")
+	} else {
+		ctx.WriteKeyWord(" BETWEEN ")
+	}
+	if err := n.Left.Restore(ctx); err != nil {
+		return errors.Annotate(err, "An error occurred while restore BetweenExpr.Left")
+	}
+	ctx.WriteKeyWord(" AND ")
+	if err := n.Right.Restore(ctx); err != nil {
+		return errors.Annotate(err, "An error occurred while restore BetweenExpr.Right ")
+	}
+	return nil
 }
 
 // Format the ExprNode into a Writer.
@@ -137,8 +152,8 @@ type BinaryOperationExpr struct {
 	R ExprNode
 }
 
-// Restore implements Recoverable interface.
-func (n *BinaryOperationExpr) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *BinaryOperationExpr) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -183,8 +198,8 @@ type WhenClause struct {
 	Result ExprNode
 }
 
-// Restore implements Recoverable interface.
-func (n *WhenClause) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *WhenClause) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -221,8 +236,8 @@ type CaseExpr struct {
 	ElseClause ExprNode
 }
 
-// Restore implements Recoverable interface.
-func (n *CaseExpr) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *CaseExpr) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -290,8 +305,8 @@ type SubqueryExpr struct {
 	Exists     bool
 }
 
-// Restore implements Recoverable interface.
-func (n *SubqueryExpr) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *SubqueryExpr) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -331,8 +346,8 @@ type CompareSubqueryExpr struct {
 	All bool
 }
 
-// Restore implements Recoverable interface.
-func (n *CompareSubqueryExpr) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *CompareSubqueryExpr) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -369,17 +384,17 @@ type ColumnName struct {
 	Name   model.CIStr
 }
 
-// Restore implements Recoverable interface.
-func (n *ColumnName) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *ColumnName) Restore(ctx *RestoreCtx) error {
 	if n.Schema.O != "" {
-		WriteName(sb, n.Schema.O)
-		sb.WriteString(".")
+		ctx.WriteName(n.Schema.O)
+		ctx.WritePlain(".")
 	}
 	if n.Table.O != "" {
-		WriteName(sb, n.Table.O)
-		sb.WriteString(".")
+		ctx.WriteName(n.Table.O)
+		ctx.WritePlain(".")
 	}
-	WriteName(sb, n.Name.O)
+	ctx.WriteName(n.Name.O)
 	return nil
 }
 
@@ -431,10 +446,9 @@ type ColumnNameExpr struct {
 	Refer *ResultField
 }
 
-// Restore implements Recoverable interface.
-func (n *ColumnNameExpr) Restore(sb *strings.Builder) error {
-	err := n.Name.Restore(sb)
-	if err != nil {
+// Restore implements Node interface.
+func (n *ColumnNameExpr) Restore(ctx *RestoreCtx) error {
+	if err := n.Name.Restore(ctx); err != nil {
 		return errors.Trace(err)
 	}
 	return nil
@@ -468,8 +482,8 @@ type DefaultExpr struct {
 	Name *ColumnName
 }
 
-// Restore implements Recoverable interface.
-func (n *DefaultExpr) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *DefaultExpr) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -505,8 +519,8 @@ type ExistsSubqueryExpr struct {
 	Not bool
 }
 
-// Restore implements Recoverable interface.
-func (n *ExistsSubqueryExpr) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *ExistsSubqueryExpr) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -543,8 +557,8 @@ type PatternInExpr struct {
 	Sel ExprNode
 }
 
-// Restore implements Recoverable interface.
-func (n *PatternInExpr) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *PatternInExpr) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -603,9 +617,16 @@ type IsNullExpr struct {
 	Not bool
 }
 
-// Restore implements Recoverable interface.
-func (n *IsNullExpr) Restore(sb *strings.Builder) error {
-	n.Format(sb)
+// Restore implements Node interface.
+func (n *IsNullExpr) Restore(ctx *RestoreCtx) error {
+	if err := n.Expr.Restore(ctx); err != nil {
+		return errors.Trace(err)
+	}
+	if n.Not {
+		ctx.WriteKeyWord(" IS NOT NULL")
+	} else {
+		ctx.WriteKeyWord(" IS NULL")
+	}
 	return nil
 }
 
@@ -645,8 +666,8 @@ type IsTruthExpr struct {
 	True int64
 }
 
-// Restore implements Recoverable interface.
-func (n *IsTruthExpr) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *IsTruthExpr) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -696,8 +717,8 @@ type PatternLikeExpr struct {
 	PatTypes []byte
 }
 
-// Restore implements Recoverable interface.
-func (n *PatternLikeExpr) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *PatternLikeExpr) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -754,8 +775,8 @@ type ParenthesesExpr struct {
 	Expr ExprNode
 }
 
-// Restore implements Recoverable interface.
-func (n *ParenthesesExpr) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *ParenthesesExpr) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -796,8 +817,8 @@ type PositionExpr struct {
 	Refer *ResultField
 }
 
-// Restore implements Recoverable interface.
-func (n *PositionExpr) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *PositionExpr) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -839,8 +860,8 @@ type PatternRegexpExpr struct {
 	Sexpr *string
 }
 
-// Restore implements Recoverable interface.
-func (n *PatternRegexpExpr) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *PatternRegexpExpr) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -883,8 +904,8 @@ type RowExpr struct {
 	Values []ExprNode
 }
 
-// Restore implements Recoverable interface.
-func (n *RowExpr) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *RowExpr) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -919,9 +940,14 @@ type UnaryOperationExpr struct {
 	V ExprNode
 }
 
-// Restore implements Recoverable interface.
-func (n *UnaryOperationExpr) Restore(sb *strings.Builder) error {
-	n.Format(sb)
+// Restore implements Node interface.
+func (n *UnaryOperationExpr) Restore(ctx *RestoreCtx) error {
+	if err := n.Op.Restore(ctx.In); err != nil {
+		return errors.Trace(err)
+	}
+	if err := n.V.Restore(ctx); err != nil {
+		return errors.Trace(err)
+	}
 	return nil
 }
 
@@ -953,8 +979,8 @@ type ValuesExpr struct {
 	Column *ColumnNameExpr
 }
 
-// Restore implements Recoverable interface.
-func (n *ValuesExpr) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *ValuesExpr) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -995,8 +1021,8 @@ type VariableExpr struct {
 	Value ExprNode
 }
 
-// Restore implements Recoverable interface.
-func (n *VariableExpr) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *VariableExpr) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -1029,8 +1055,8 @@ type MaxValueExpr struct {
 	exprNode
 }
 
-// Restore implements Recoverable interface.
-func (n *MaxValueExpr) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *MaxValueExpr) Restore(ctx *RestoreCtx) error {
 	panic("Not implemented")
 }
 
diff --git a/vendor/github.com/pingcap/parser/ast/functions.go b/vendor/github.com/pingcap/parser/ast/functions.go
index 6de8d586604629f332209678f3ade538bdd83db0..e3500c67e5f8c9b4236a527b0c360b1090652229 100644
--- a/vendor/github.com/pingcap/parser/ast/functions.go
+++ b/vendor/github.com/pingcap/parser/ast/functions.go
@@ -16,7 +16,6 @@ package ast
 import (
 	"fmt"
 	"io"
-	"strings"
 
 	"github.com/pingcap/errors"
 	"github.com/pingcap/parser/model"
@@ -329,8 +328,8 @@ type FuncCallExpr struct {
 	Args []ExprNode
 }
 
-// Restore implements Recoverable interface.
-func (n *FuncCallExpr) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *FuncCallExpr) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -406,8 +405,8 @@ type FuncCastExpr struct {
 	FunctionType CastFunctionType
 }
 
-// Restore implements Recoverable interface.
-func (n *FuncCastExpr) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *FuncCastExpr) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -519,8 +518,8 @@ type AggregateFuncExpr struct {
 	Distinct bool
 }
 
-// Restore implements Recoverable interface.
-func (n *AggregateFuncExpr) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *AggregateFuncExpr) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -592,8 +591,8 @@ type WindowFuncExpr struct {
 	Spec WindowSpec
 }
 
-// Restore implements Recoverable interface.
-func (n *WindowFuncExpr) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *WindowFuncExpr) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
diff --git a/vendor/github.com/pingcap/parser/ast/misc.go b/vendor/github.com/pingcap/parser/ast/misc.go
index 20d7120c740449b15d734ffa2c0632af9abe0b5e..b96210789ffcc6eaa86cc6097406487c398aef05 100644
--- a/vendor/github.com/pingcap/parser/ast/misc.go
+++ b/vendor/github.com/pingcap/parser/ast/misc.go
@@ -98,8 +98,8 @@ type TraceStmt struct {
 	Format string
 }
 
-// Restore implements Recoverable interface.
-func (n *TraceStmt) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *TraceStmt) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -129,8 +129,8 @@ type ExplainStmt struct {
 	Analyze bool
 }
 
-// Restore implements Recoverable interface.
-func (n *ExplainStmt) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *ExplainStmt) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -160,8 +160,8 @@ type PrepareStmt struct {
 	SQLVar  *VariableExpr
 }
 
-// Restore implements Recoverable interface.
-func (n *PrepareStmt) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *PrepareStmt) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -190,8 +190,8 @@ type DeallocateStmt struct {
 	Name string
 }
 
-// Restore implements Recoverable interface.
-func (n *DeallocateStmt) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *DeallocateStmt) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -223,8 +223,8 @@ type ExecuteStmt struct {
 	ExecID    uint32
 }
 
-// Restore implements Recoverable interface.
-func (n *ExecuteStmt) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *ExecuteStmt) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -251,8 +251,8 @@ type BeginStmt struct {
 	stmtNode
 }
 
-// Restore implements Recoverable interface.
-func (n *BeginStmt) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *BeginStmt) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -274,8 +274,8 @@ type BinlogStmt struct {
 	Str string
 }
 
-// Restore implements Recoverable interface.
-func (n *BinlogStmt) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *BinlogStmt) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -295,8 +295,8 @@ type CommitStmt struct {
 	stmtNode
 }
 
-// Restore implements Recoverable interface.
-func (n *CommitStmt) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *CommitStmt) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -316,8 +316,8 @@ type RollbackStmt struct {
 	stmtNode
 }
 
-// Restore implements Recoverable interface.
-func (n *RollbackStmt) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *RollbackStmt) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -339,10 +339,10 @@ type UseStmt struct {
 	DBName string
 }
 
-// Restore implements Recoverable interface.
-func (n *UseStmt) Restore(sb *strings.Builder) error {
-	sb.WriteString("USE ")
-	WriteName(sb, n.DBName)
+// Restore implements Node interface.
+func (n *UseStmt) Restore(ctx *RestoreCtx) error {
+	ctx.WriteKeyWord("USE ")
+	ctx.WriteName(n.DBName)
 	return nil
 }
 
@@ -377,8 +377,8 @@ type VariableAssignment struct {
 	ExtendValue ValueExpr
 }
 
-// Restore implements Recoverable interface.
-func (n *VariableAssignment) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *VariableAssignment) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -418,8 +418,8 @@ type FlushStmt struct {
 	ReadLock        bool
 }
 
-// Restore implements Recoverable interface.
-func (n *FlushStmt) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *FlushStmt) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -453,8 +453,8 @@ type KillStmt struct {
 	TiDBExtension bool
 }
 
-// Restore implements Recoverable interface.
-func (n *KillStmt) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *KillStmt) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -475,8 +475,8 @@ type SetStmt struct {
 	Variables []*VariableAssignment
 }
 
-// Restore implements Recoverable interface.
-func (n *SetStmt) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *SetStmt) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -527,8 +527,8 @@ type SetPwdStmt struct {
 	Password string
 }
 
-// Restore implements Recoverable interface.
-func (n *SetPwdStmt) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *SetPwdStmt) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -595,8 +595,8 @@ type CreateUserStmt struct {
 	Specs       []*UserSpec
 }
 
-// Restore implements Recoverable interface.
-func (n *CreateUserStmt) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *CreateUserStmt) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -631,8 +631,8 @@ type AlterUserStmt struct {
 	Specs       []*UserSpec
 }
 
-// Restore implements Recoverable interface.
-func (n *AlterUserStmt) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *AlterUserStmt) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -666,8 +666,8 @@ type DropUserStmt struct {
 	UserList []*auth.UserIdentity
 }
 
-// Restore implements Recoverable interface.
-func (n *DropUserStmt) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *DropUserStmt) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -688,8 +688,8 @@ type DoStmt struct {
 	Exprs []ExprNode
 }
 
-// Restore implements Recoverable interface.
-func (n *DoStmt) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *DoStmt) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -780,8 +780,8 @@ type AdminStmt struct {
 	ShowSlow     *ShowSlow
 }
 
-// Restore implements Recoverable interface.
-func (n *AdminStmt) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *AdminStmt) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -812,8 +812,8 @@ type PrivElem struct {
 	Cols []*ColumnName
 }
 
-// Restore implements Recoverable interface.
-func (n *PrivElem) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *PrivElem) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -875,8 +875,8 @@ type RevokeStmt struct {
 	Users      []*UserSpec
 }
 
-// Restore implements Recoverable interface.
-func (n *RevokeStmt) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *RevokeStmt) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -908,8 +908,8 @@ type GrantStmt struct {
 	WithGrant  bool
 }
 
-// Restore implements Recoverable interface.
-func (n *GrantStmt) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *GrantStmt) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -978,8 +978,8 @@ type TableOptimizerHint struct {
 	MaxExecutionTime uint64
 }
 
-// Restore implements Recoverable interface.
-func (n *TableOptimizerHint) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *TableOptimizerHint) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
diff --git a/vendor/github.com/pingcap/parser/ast/stats.go b/vendor/github.com/pingcap/parser/ast/stats.go
index aad6a84037eba34abf6b140d86d742849c84b706..2a26cb919ba9d266ec1aed44e6e0eef4638f0464 100644
--- a/vendor/github.com/pingcap/parser/ast/stats.go
+++ b/vendor/github.com/pingcap/parser/ast/stats.go
@@ -14,8 +14,6 @@
 package ast
 
 import (
-	"strings"
-
 	"github.com/pingcap/errors"
 	"github.com/pingcap/parser/model"
 )
@@ -39,8 +37,8 @@ type AnalyzeTableStmt struct {
 	IndexFlag bool
 }
 
-// Restore implements Recoverable interface.
-func (n *AnalyzeTableStmt) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *AnalyzeTableStmt) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -68,8 +66,8 @@ type DropStatsStmt struct {
 	Table *TableName
 }
 
-// Restore implements Recoverable interface.
-func (n *DropStatsStmt) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *DropStatsStmt) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
@@ -95,8 +93,8 @@ type LoadStatsStmt struct {
 	Path string
 }
 
-// Restore implements Recoverable interface.
-func (n *LoadStatsStmt) Restore(sb *strings.Builder) error {
+// Restore implements Node interface.
+func (n *LoadStatsStmt) Restore(ctx *RestoreCtx) error {
 	return errors.New("Not implemented")
 }
 
diff --git a/vendor/github.com/pingcap/parser/ast/util.go b/vendor/github.com/pingcap/parser/ast/util.go
index b2bd5468901daaa465826a31678a5af5d015a374..1569d2462bffc62bbfb305d7649421599edd7047 100644
--- a/vendor/github.com/pingcap/parser/ast/util.go
+++ b/vendor/github.com/pingcap/parser/ast/util.go
@@ -13,7 +13,11 @@
 
 package ast
 
-import "strings"
+import (
+	"fmt"
+	"io"
+	"strings"
+)
 
 // IsReadOnly checks whether the input ast is readOnly.
 func IsReadOnly(node Node) bool {
@@ -62,14 +66,150 @@ func (checker *readOnlyChecker) Leave(in Node) (out Node, ok bool) {
 	return in, checker.readOnly
 }
 
-// WriteName append escaped `name` with back quote to `sb`.
-func WriteName(sb *strings.Builder, name string) {
-	sb.WriteString("`")
-	sb.WriteString(EscapeName(name))
-	sb.WriteString("`")
+//RestoreFlag mark the Restore format
+type RestoreFlags uint64
+
+// Mutually exclusive group of `RestoreFlags`:
+// [RestoreStringSingleQuotes, RestoreStringDoubleQuotes]
+// [RestoreKeyWordUppercase, RestoreKeyWordLowercase]
+// [RestoreNameUppercase, RestoreNameLowercase]
+// [RestoreNameDoubleQuotes, RestoreNameBackQuotes]
+// The flag with the left position in each group has a higher priority.
+const (
+	RestoreStringSingleQuotes RestoreFlags = 1 << iota
+	RestoreStringDoubleQuotes
+	RestoreStringEscapeBackslash
+
+	RestoreKeyWordUppercase
+	RestoreKeyWordLowercase
+
+	RestoreNameUppercase
+	RestoreNameLowercase
+	RestoreNameDoubleQuotes
+	RestoreNameBackQuotes
+)
+
+const (
+	DefaultRestoreFlags = RestoreStringSingleQuotes | RestoreKeyWordUppercase | RestoreNameBackQuotes
+)
+
+func (rf RestoreFlags) has(flag RestoreFlags) bool {
+	return rf&flag != 0
+}
+
+// HasStringSingleQuotesFlag returns a boolean indicating when `rf` has `RestoreStringSingleQuotes` flag.
+func (rf RestoreFlags) HasStringSingleQuotesFlag() bool {
+	return rf.has(RestoreStringSingleQuotes)
+}
+
+// HasStringDoubleQuotesFlag returns a boolean indicating whether `rf` has `RestoreStringDoubleQuotes` flag.
+func (rf RestoreFlags) HasStringDoubleQuotesFlag() bool {
+	return rf.has(RestoreStringDoubleQuotes)
+}
+
+// HasStringEscapeBackslashFlag returns a boolean indicating whether `rf` has `RestoreStringEscapeBackslash` flag.
+func (rf RestoreFlags) HasStringEscapeBackslashFlag() bool {
+	return rf.has(RestoreStringEscapeBackslash)
+}
+
+// HasKeyWordUppercaseFlag returns a boolean indicating whether `rf` has `RestoreKeyWordUppercase` flag.
+func (rf RestoreFlags) HasKeyWordUppercaseFlag() bool {
+	return rf.has(RestoreKeyWordUppercase)
+}
+
+// HasKeyWordLowercaseFlag returns a boolean indicating whether `rf` has `RestoreKeyWordLowercase` flag.
+func (rf RestoreFlags) HasKeyWordLowercaseFlag() bool {
+	return rf.has(RestoreKeyWordLowercase)
+}
+
+// HasNameUppercaseFlag returns a boolean indicating whether `rf` has `RestoreNameUppercase` flag.
+func (rf RestoreFlags) HasNameUppercaseFlag() bool {
+	return rf.has(RestoreNameUppercase)
+}
+
+// HasNameLowercaseFlag returns a boolean indicating whether `rf` has `RestoreNameLowercase` flag.
+func (rf RestoreFlags) HasNameLowercaseFlag() bool {
+	return rf.has(RestoreNameLowercase)
+}
+
+// HasNameDoubleQuotesFlag returns a boolean indicating whether `rf` has `RestoreNameDoubleQuotes` flag.
+func (rf RestoreFlags) HasNameDoubleQuotesFlag() bool {
+	return rf.has(RestoreNameDoubleQuotes)
+}
+
+// HasNameBackQuotesFlag returns a boolean indicating whether `rf` has `RestoreNameBackQuotes` flag.
+func (rf RestoreFlags) HasNameBackQuotesFlag() bool {
+	return rf.has(RestoreNameBackQuotes)
+}
+
+// RestoreCtx is `Restore` context to hold flags and writer.
+type RestoreCtx struct {
+	Flags RestoreFlags
+	In    io.Writer
+}
+
+// NewRestoreCtx returns a new `RestoreCtx`.
+func NewRestoreCtx(flags RestoreFlags, in io.Writer) *RestoreCtx {
+	return &RestoreCtx{flags, in}
+}
+
+// WriteKeyWord writes the `keyWord` into writer.
+// `keyWord` will be converted format(uppercase and lowercase for now) according to `RestoreFlags`.
+func (ctx *RestoreCtx) WriteKeyWord(keyWord string) {
+	switch {
+	case ctx.Flags.HasKeyWordUppercaseFlag():
+		keyWord = strings.ToUpper(keyWord)
+	case ctx.Flags.HasKeyWordLowercaseFlag():
+		keyWord = strings.ToLower(keyWord)
+	}
+	fmt.Fprint(ctx.In, keyWord)
+}
+
+// WriteString writes the string into writer
+// `str` may be wrapped in quotes and escaped according to RestoreFlags.
+func (ctx *RestoreCtx) WriteString(str string) {
+	if ctx.Flags.HasStringEscapeBackslashFlag() {
+		str = strings.Replace(str, `\`, `\\`, -1)
+	}
+	quotes := ""
+	switch {
+	case ctx.Flags.HasStringSingleQuotesFlag():
+		str = strings.Replace(str, `'`, `''`, -1)
+		quotes = `'`
+	case ctx.Flags.HasStringDoubleQuotesFlag():
+		str = strings.Replace(str, `"`, `""`, -1)
+		quotes = `"`
+	}
+	fmt.Fprint(ctx.In, quotes, str, quotes)
+}
+
+// WriteName writes the name into writer
+// `name` maybe wrapped in quotes and escaped according to RestoreFlags.
+func (ctx *RestoreCtx) WriteName(name string) {
+	switch {
+	case ctx.Flags.HasNameUppercaseFlag():
+		name = strings.ToUpper(name)
+	case ctx.Flags.HasNameLowercaseFlag():
+		name = strings.ToLower(name)
+	}
+	quotes := ""
+	switch {
+	case ctx.Flags.HasNameDoubleQuotesFlag():
+		name = strings.Replace(name, `"`, `""`, -1)
+		quotes = `"`
+	case ctx.Flags.HasNameBackQuotesFlag():
+		name = strings.Replace(name, "`", "``", -1)
+		quotes = "`"
+	}
+	fmt.Fprint(ctx.In, quotes, name, quotes)
+}
+
+// WritePlain writes the plain text into writer without any handling.
+func (ctx *RestoreCtx) WritePlain(plainText string) {
+	fmt.Fprint(ctx.In, plainText)
 }
 
-// EscapeName escape the `name`
-func EscapeName(name string) string {
-	return strings.Replace(name, "`", "``", -1)
+// WritePlainf write the plain text into writer without any handling.
+func (ctx *RestoreCtx) WritePlainf(format string, a ...interface{}) {
+	fmt.Fprintf(ctx.In, format, a...)
 }
diff --git a/vendor/github.com/pingcap/parser/go.mod1 b/vendor/github.com/pingcap/parser/go.mod1
index 9b6f5fdf8d70091bf5cd28614ba71561ed325dbc..cfc68ae2e2375e699107ec5c1ea17e46cab73788 100644
--- a/vendor/github.com/pingcap/parser/go.mod1
+++ b/vendor/github.com/pingcap/parser/go.mod1
@@ -7,11 +7,10 @@ require (
 	github.com/cznic/sortutil v0.0.0-20150617083342-4c7342852e65
 	github.com/cznic/strutil v0.0.0-20171016134553-529a34b1c186
 	github.com/cznic/y v0.0.0-20170802143616-045f81c6662a
-	github.com/pingcap/check v0.0.0-20171206051426-1c287c953996
+	github.com/pingcap/check v0.0.0-20181213055612-5c2b07721bdb
 	github.com/pingcap/errors v0.11.0
-	github.com/pingcap/tidb v0.0.0-20181203021530-741adcee43e2
+	github.com/pingcap/tidb v0.0.0-20181217070741-096bb68e6bef
 	github.com/pingcap/tipb v0.0.0-20181012112600-11e33c750323
 	github.com/sirupsen/logrus v1.2.0
-	golang.org/x/net v0.0.0-20181029044818-c44066c5c816
 	golang.org/x/text v0.3.0
 )
diff --git a/vendor/github.com/pingcap/parser/go.sum1 b/vendor/github.com/pingcap/parser/go.sum1
index 24313c746a0cb35c7994608bdf8d109ba5bff709..02668a3f0423d05c8251c9f8819ee7c91e2b1f4e 100644
--- a/vendor/github.com/pingcap/parser/go.sum1
+++ b/vendor/github.com/pingcap/parser/go.sum1
@@ -1,23 +1,18 @@
 cloud.google.com/go v0.26.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
-cloud.google.com/go v0.31.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
 github.com/BurntSushi/toml v0.3.1 h1:WXkYYl6Yr3qBf1K79EBnL4mak0OimBfB0XUf9Vl28OQ=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
-github.com/Shopify/sarama v1.19.0/go.mod h1:FVkBWblsNy7DGZRfXLU0O9RCGt5g3g3yEuWXgklEdEo=
-github.com/Shopify/toxiproxy v2.1.3+incompatible/go.mod h1:OXgGpZ6Cli1/URJOF1DMxUHB2q5Ap20/P/eIdh4G0pI=
+github.com/StackExchange/wmi v0.0.0-20180725035823-b12b22c5341f h1:5ZfJxyXo8KyX8DgGXC5B7ILL8y51fci/qYz2B4j8iLY=
 github.com/StackExchange/wmi v0.0.0-20180725035823-b12b22c5341f/go.mod h1:3eOhrUMpNV+6aFIbp5/iudMxNCF27Vw2OZgy4xEx0Fg=
-github.com/apache/thrift v0.0.0-20161221203622-b2a4d4ae21c7/go.mod h1:cp2SuWMxlEZw2r+iP2GNCdIi4C1qmUzdZFSVb+bacwQ=
 github.com/beorn7/perks v0.0.0-20180321164747-3a771d992973 h1:xJ4a3vCFaGF/jqvzLMYoU8P317H5OQ+Via4RmuPwCS0=
 github.com/beorn7/perks v0.0.0-20180321164747-3a771d992973/go.mod h1:Dwedo/Wpr24TaqPxmxbtue+5NUziq4I4S80YR8gNf3Q=
 github.com/blacktear23/go-proxyprotocol v0.0.0-20171102103907-62e368e1c470/go.mod h1:VKt7CNAQxpFpSDz3sXyj9hY/GbVsQCr0sB3w59nE7lU=
+github.com/boltdb/bolt v1.3.1 h1:JQmyP4ZBrce+ZQu0dY660FMfatumYDLun9hBCUVIkF4=
 github.com/boltdb/bolt v1.3.1/go.mod h1:clJnj/oiGkjum5o1McbSZDSLxVThjynRyGBgiAx27Ps=
-github.com/chzyer/readline v0.0.0-20171208011716-f6d7a1f6fbf3/go.mod h1:nSuG5e5PlCu98SY8svDHJxuZscDgtXS6KTTbou5AhLI=
 github.com/client9/misspell v0.3.4/go.mod h1:qj6jICC3Q7zFZvVWo7KLAzC3yx5G7kyvSDkc90ppPyw=
-github.com/cockroachdb/cmux v0.0.0-20170110192607-30d10be49292/go.mod h1:qRiX68mZX1lGBkTWyp3CLcenw9I94W2dLeRvMzcn9N4=
 github.com/codahale/hdrhistogram v0.0.0-20161010025455-3a0bb77429bd h1:qMd81Ts1T2OTKmB4acZcyKaMtRnY5Y44NuXGX2GFJ1w=
 github.com/codahale/hdrhistogram v0.0.0-20161010025455-3a0bb77429bd/go.mod h1:sE/e/2PUdi/liOCUjSTXgM1o87ZssimdTWN964YiIeI=
+github.com/coreos/bbolt v1.3.0 h1:HIgH5xUWXT914HCI671AxuTTqjj64UOFr7pHn48LUTI=
 github.com/coreos/bbolt v1.3.0/go.mod h1:iRUV2dpdMOn7Bo10OQBFzIJO9kkE559Wcmn+qkEiiKk=
-github.com/coreos/bbolt v1.3.1-coreos.6 h1:uTXKg9gY70s9jMAKdfljFQcuh4e/BXOM+V+d00KFj3A=
-github.com/coreos/bbolt v1.3.1-coreos.6/go.mod h1:iRUV2dpdMOn7Bo10OQBFzIJO9kkE559Wcmn+qkEiiKk=
 github.com/coreos/etcd v3.3.10+incompatible h1:KjVWqrZ5U0wa3CxY2AxlH6/UcB+PK2td1DcsYhA+HRs=
 github.com/coreos/etcd v3.3.10+incompatible/go.mod h1:uF7uidLiAD3TWHmW31ZFd/JWoc32PjwdhPthX9715RE=
 github.com/coreos/go-semver v0.2.0 h1:3Jm3tLmsgAYcjC+4Up7hJrFBPr+n7rAqYeSw/SZazuY=
@@ -26,8 +21,6 @@ github.com/coreos/go-systemd v0.0.0-20181031085051-9002847aa142 h1:3jFq2xL4ZajGK
 github.com/coreos/go-systemd v0.0.0-20181031085051-9002847aa142/go.mod h1:F5haX7vjVVG0kc13fIWeqUViNPyEJxv/OmvnBo0Yme4=
 github.com/coreos/pkg v0.0.0-20180928190104-399ea9e2e55f h1:lBNOc5arjvs8E5mO2tbpBpLoyyu8B6e44T7hJy6potg=
 github.com/coreos/pkg v0.0.0-20180928190104-399ea9e2e55f/go.mod h1:E3G3o1h8I7cfcXa63jLwjI0eiQQMgzzUDFVpN/nH/eA=
-github.com/cznic/golex v0.0.0-20170803123110-4ab7c5e190e4 h1:CVAqftqbj+exlab+8KJQrE+kNIVlQfJt58j4GxCMF1s=
-github.com/cznic/golex v0.0.0-20170803123110-4ab7c5e190e4/go.mod h1:+bmmJDNmKlhWNG+gwWCkaBoTy39Fs+bzRxVBzoTQbIc=
 github.com/cznic/golex v0.0.0-20181122101858-9c343928389c h1:G8zTsaqyVfIHpgMFcGgdbhHSFhlNc77rAKkhVbQ9kQg=
 github.com/cznic/golex v0.0.0-20181122101858-9c343928389c/go.mod h1:+bmmJDNmKlhWNG+gwWCkaBoTy39Fs+bzRxVBzoTQbIc=
 github.com/cznic/mathutil v0.0.0-20181021201202-eba54fb065b7 h1:y+DH9ARrWiiNBV+6waYP2IPcsRbxdU1qsnycPfShF4c=
@@ -46,9 +39,6 @@ github.com/dgrijalva/jwt-go v3.2.0+incompatible h1:7qlOGliEKZXTDg6OTjfoBKDXWrumC
 github.com/dgrijalva/jwt-go v3.2.0+incompatible/go.mod h1:E3ru+11k8xSBh+hMPgOLZmtrrCbhqsmaPHjLKYnJCaQ=
 github.com/dustin/go-humanize v1.0.0 h1:VSnTsYCnlFHaM2/igO1h6X3HA71jcobQuxemgkq4zYo=
 github.com/dustin/go-humanize v1.0.0/go.mod h1:HtrtbFcZ19U5GC7JDqmcUSB87Iq5E25KnS6fMYU6eOk=
-github.com/eapache/go-resiliency v1.1.0/go.mod h1:kFI+JgMyC7bLPUVY133qvEBtVayf5mFgVsvEsIPBvNs=
-github.com/eapache/go-xerial-snappy v0.0.0-20180814174437-776d5712da21/go.mod h1:+020luEh2TKB4/GOp8oxxtq0Daoen/Cii55CzbTV6DU=
-github.com/eapache/queue v0.0.0-20180227141424-093482f3f8ce/go.mod h1:6eCeP0CKFpHLu8blIFXhExK/dRa7WDZfr6jVFPTqq+I=
 github.com/eknkc/amber v0.0.0-20171010120322-cdade1c07385 h1:clC1lXBpe2kTj2VHdaIu9ajZQe4kcEY9j0NsnDDBZ3o=
 github.com/eknkc/amber v0.0.0-20171010120322-cdade1c07385/go.mod h1:0vRUJqYpeSZifjYj7uP3BG/gKcuzL9xWVV/Y+cK33KM=
 github.com/etcd-io/gofail v0.0.0-20180808172546-51ce9a71510a h1:QNEenQIsGDEEfFNSnN+h6hE1OwnHqTg7Dl9gEk1Cko4=
@@ -57,6 +47,7 @@ github.com/fsnotify/fsnotify v1.4.7 h1:IXs+QLmnXW2CcXuY+8Mzv/fWEsPGWxqefPtCP5CnV
 github.com/fsnotify/fsnotify v1.4.7/go.mod h1:jwhsz4b93w/PPRr/qN1Yymfu8t87LnFCMoQvtojpjFo=
 github.com/ghodss/yaml v1.0.0 h1:wQHKEahhL6wmXdzwWG11gIVCkOv05bNOh+Rxn0yngAk=
 github.com/ghodss/yaml v1.0.0/go.mod h1:4dBDuWmgqj2HViK6kFavaiC9ZROes6MMH2rRYeMEF04=
+github.com/go-ole/go-ole v1.2.1 h1:2lOsA72HgjxAuMlKpFiCbHTvu44PIVkZ5hqm3RSdI/E=
 github.com/go-ole/go-ole v1.2.1/go.mod h1:7FAglXiTm7HKlQRDeOQ6ZNUHidzCWXuZWq/1dTyBNF8=
 github.com/go-sql-driver/mysql v0.0.0-20170715192408-3955978caca4/go.mod h1:zAC/RDZ24gD3HViQzih4MyKcchzm+sOG5ZlKdlhCg5w=
 github.com/gogo/protobuf v1.1.1 h1:72R+M5VuhED/KujmZVcIquuo8mBgX4oVda//DQb3PXo=
@@ -66,7 +57,6 @@ github.com/golang/glog v0.0.0-20160126235308-23def4e6c14b/go.mod h1:SBH7ygxi8pfU
 github.com/golang/groupcache v0.0.0-20181024230925-c65c006176ff h1:kOkM9whyQYodu09SJ6W3NCsHG7crFaJILQ22Gozp3lg=
 github.com/golang/groupcache v0.0.0-20181024230925-c65c006176ff/go.mod h1:cIg4eruTrX1D+g88fzRXU5OdNfaM+9IcxsU14FzY7Hc=
 github.com/golang/lint v0.0.0-20180702182130-06c8688daad7/go.mod h1:tluoj9z5200jBnyusfRPU2LqT6J+DAorxEvtC7LHB+E=
-github.com/golang/lint v0.0.0-20181026193005-c67002cb31c3/go.mod h1:tluoj9z5200jBnyusfRPU2LqT6J+DAorxEvtC7LHB+E=
 github.com/golang/mock v1.1.1/go.mod h1:oTYuIxOrZwtPieC+H1uAHpcLFnEyAGVDL/k47Jfbm0A=
 github.com/golang/protobuf v1.2.0 h1:P3YflyNX/ehuJFLhxviNdFxQPkGK5cDcApsge1SqnvM=
 github.com/golang/protobuf v1.2.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
@@ -78,8 +68,7 @@ github.com/gorilla/context v1.1.1 h1:AWwleXJkX/nhcU9bZSnZoi3h/qGYqQAGhq6zZe/aQW8
 github.com/gorilla/context v1.1.1/go.mod h1:kBGZzfjB9CEq2AlWe17Uuf7NDRt0dE0s8S51q0aT7Yg=
 github.com/gorilla/mux v1.6.2 h1:Pgr17XVTNXAk3q/r4CpKzC5xBM/qW1uVLV+IhRZpIIk=
 github.com/gorilla/mux v1.6.2/go.mod h1:1lud6UwP+6orDFRuTfBEV8e9/aOM/c4fVVCaMa2zaAs=
-github.com/gorilla/websocket v1.2.0 h1:VJtLvh6VQym50czpZzx07z/kw9EgAxI3x1ZB8taTMQQ=
-github.com/gorilla/websocket v1.2.0/go.mod h1:E7qHFY5m1UJ88s3WnNqhKjPHQ0heANvMoAMk2YaljkQ=
+github.com/gorilla/websocket v1.4.0 h1:WDFjx/TMzVgy9VdMMQi2K2Emtwi2QcUQsztZ/zLaH/Q=
 github.com/gorilla/websocket v1.4.0/go.mod h1:E7qHFY5m1UJ88s3WnNqhKjPHQ0heANvMoAMk2YaljkQ=
 github.com/grpc-ecosystem/go-grpc-middleware v1.0.0 h1:BWIsLfhgKhV5g/oF34aRjniBHLTZe5DNekSjbAjIS6c=
 github.com/grpc-ecosystem/go-grpc-middleware v1.0.0/go.mod h1:FiyG127CGDf3tlThmgyCl78X/SZQqEOJBCDaAfeWzPs=
@@ -89,88 +78,47 @@ github.com/grpc-ecosystem/grpc-gateway v1.5.1 h1:3scN4iuXkNOyP98jF55Lv8a9j1o/Iwv
 github.com/grpc-ecosystem/grpc-gateway v1.5.1/go.mod h1:RSKVYQBd5MCa4OVpNdGskqpgL2+G+NZTnrVHpWWfpdw=
 github.com/hpcloud/tail v1.0.0 h1:nfCOvKYfkgYP8hkirhJocXT2+zOD8yUNjXaWfTlyFKI=
 github.com/hpcloud/tail v1.0.0/go.mod h1:ab1qPbhIpdTxEkNHXyeSf5vhxWSCs/tWer42PpOxQnU=
-github.com/inconshreveable/mousetrap v1.0.0/go.mod h1:PxqpIevigyE2G7u3NXJIT2ANytuPF1OarO4DADm73n8=
 github.com/jonboulle/clockwork v0.1.0 h1:VKV+ZcuP6l3yW9doeqz6ziZGgcynBVQO+obU0+0hcPo=
 github.com/jonboulle/clockwork v0.1.0/go.mod h1:Ii8DK3G1RaLaWxj9trq07+26W01tbo22gdxWY5EU2bo=
-github.com/juju/errors v0.0.0-20181012004132-a4583d0a56ea h1:g2k+8WR7cHch4g0tBDhfiEvAp7fXxTNBiD1oC1Oxj3E=
-github.com/juju/errors v0.0.0-20181012004132-a4583d0a56ea/go.mod h1:W54LbzXuIE0boCoNJfwqpmkKJ1O4TCTZMetAt6jGk7Q=
-github.com/juju/loggo v0.0.0-20180524022052-584905176618 h1:MK144iBQF9hTSwBW/9eJm034bVoG30IshVm688T2hi8=
-github.com/juju/loggo v0.0.0-20180524022052-584905176618/go.mod h1:vgyd7OREkbtVEN/8IXZe5Ooef3LQePvuBm9UWj6ZL8U=
-github.com/juju/testing v0.0.0-20180920084828-472a3e8b2073 h1:WQM1NildKThwdP7qWrNAFGzp4ijNLw8RlgENkaI4MJs=
-github.com/juju/testing v0.0.0-20180920084828-472a3e8b2073/go.mod h1:63prj8cnj0tU0S9OHjGJn+b1h0ZghCndfnbQolrYTwA=
 github.com/kisielk/gotool v1.0.0/go.mod h1:XhKaO+MFFWcvkIS/tQcRk01m1F5IRFswLeQ+oQHNcck=
 github.com/klauspost/cpuid v0.0.0-20170728055534-ae7887de9fa5 h1:2U0HzY8BJ8hVwDKIzp7y4voR9CX/nvcfymLmg2UiOio=
 github.com/klauspost/cpuid v0.0.0-20170728055534-ae7887de9fa5/go.mod h1:Pj4uuM528wm8OyEC2QMXAi2YiTZ96dNQPGgoMS4s3ek=
 github.com/konsorten/go-windows-terminal-sequences v1.0.1 h1:mweAR1A6xJ3oS2pRaGiHgQ4OO8tzTaLawm8vnODuwDk=
 github.com/konsorten/go-windows-terminal-sequences v1.0.1/go.mod h1:T0+1ngSBFLxvqU3pZ+m/2kptfBszLMUkC4ZK/EgS/cQ=
-github.com/kr/pretty v0.1.0 h1:L/CwN0zerZDmRFUapSPitk6f+Q3+0za1rQkzVuMiMFI=
-github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORNo=
-github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
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-go.uber.org/zap v1.8.0 h1:r6Za1Rii8+EGOYRDLvpooNOF6kP3iyDnkpzbw67gCQ8=
-go.uber.org/zap v1.8.0/go.mod h1:vwi/ZaCAaUcBkycHslxD9B2zi4UTXhF60s6SWpuDF0Q=
+go.uber.org/zap v1.9.1 h1:XCJQEf3W6eZaVwhRBof6ImoYGJSITeKWsyeh3HFu/5o=
 go.uber.org/zap v1.9.1/go.mod h1:vwi/ZaCAaUcBkycHslxD9B2zi4UTXhF60s6SWpuDF0Q=
 golang.org/x/crypto v0.0.0-20180904163835-0709b304e793 h1:u+LnwYTOOW7Ukr/fppxEb1Nwz0AtPflrblfvUudpo+I=
 golang.org/x/crypto v0.0.0-20180904163835-0709b304e793/go.mod h1:6SG95UA2DQfeDnfUPMdvaQW0Q7yPrPDi9nlGo2tz2b4=
-golang.org/x/crypto v0.0.0-20181030102418-4d3f4d9ffa16 h1:y6ce7gCWtnH+m3dCjzQ1PCuwl28DDIc3VNnvY29DlIA=
-golang.org/x/crypto v0.0.0-20181030102418-4d3f4d9ffa16/go.mod h1:6SG95UA2DQfeDnfUPMdvaQW0Q7yPrPDi9nlGo2tz2b4=
 golang.org/x/lint v0.0.0-20180702182130-06c8688daad7/go.mod h1:UVdnD1Gm6xHRNCYTkRU2/jEulfH38KcIWyp/GAMgvoE=
-golang.org/x/lint v0.0.0-20181026193005-c67002cb31c3/go.mod h1:UVdnD1Gm6xHRNCYTkRU2/jEulfH38KcIWyp/GAMgvoE=
-golang.org/x/net v0.0.0-20180724234803-3673e40ba225/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20180826012351-8a410e7b638d/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20180906233101-161cd47e91fd/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20181029044818-c44066c5c816 h1:mVFkLpejdFLXVUv9E42f3XJVfMdqd0IVLVIVLjZWn5o=
 golang.org/x/net v0.0.0-20181029044818-c44066c5c816/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
-golang.org/x/oauth2 v0.0.0-20181031022657-8527f56f7107/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
 golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f h1:wMNYb4v58l5UBM7MYRLPG6ZhfOqbKu7X5eyFl8ZhKvA=
 golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sys v0.0.0-20180830151530-49385e6e1522/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
@@ -253,31 +188,20 @@ golang.org/x/sys v0.0.0-20180905080454-ebe1bf3edb33 h1:I6FyU15t786LL7oL/hn43zqTu
 golang.org/x/sys v0.0.0-20180905080454-ebe1bf3edb33/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20180909124046-d0be0721c37e h1:o3PsSEY8E4eXWkXrIP9YJALUkVZqzHJT5DOasTyn8Vs=
 golang.org/x/sys v0.0.0-20180909124046-d0be0721c37e/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
-golang.org/x/sys v0.0.0-20181031143558-9b800f95dbbc h1:SdCq5U4J+PpbSDIl9bM0V1e1Ug1jsnBkAFvTs1htn7U=
-golang.org/x/sys v0.0.0-20181031143558-9b800f95dbbc/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/text v0.3.0 h1:g61tztE5qeGQ89tm6NTjjM9VPIm088od1l6aSorWRWg=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
-golang.org/x/time v0.0.0-20180412165947-fbb02b2291d2 h1:+DCIGbF/swA92ohVg0//6X2IVY3KZs6p9mix0ziNYJM=
-golang.org/x/time v0.0.0-20180412165947-fbb02b2291d2/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
+golang.org/x/time v0.0.0-20181108054448-85acf8d2951c h1:fqgJT0MGcGpPgpWU7VRdRjuArfcOvC4AoJmILihzhDg=
 golang.org/x/time v0.0.0-20181108054448-85acf8d2951c/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
 golang.org/x/tools v0.0.0-20180828015842-6cd1fcedba52/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
-golang.org/x/tools v0.0.0-20181030221726-6c7e314b6563/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 google.golang.org/appengine v1.1.0/go.mod h1:EbEs0AVv82hx2wNQdGPgUI5lhzA/G0D9YwlJXL52JkM=
-google.golang.org/appengine v1.2.0/go.mod h1:xpcJRLb0r/rnEns0DIKYYv+WjYCduHsrkT7/EB5XEv4=
+google.golang.org/genproto v0.0.0-20180817151627-c66870c02cf8 h1:Nw54tB0rB7hY/N0NQvRW8DG4Yk3Q6T9cu9RcFQDu1tc=
 google.golang.org/genproto v0.0.0-20180817151627-c66870c02cf8/go.mod h1:JiN7NxoALGmiZfu7CAH4rXhgtRTLTxftemlI0sWmxmc=
-google.golang.org/genproto v0.0.0-20181029155118-b69ba1387ce2 h1:67iHsV9djwGdZpdZNbLuQj6FOzCaZe3w+vhLjn5AcFA=
-google.golang.org/genproto v0.0.0-20181029155118-b69ba1387ce2/go.mod h1:JiN7NxoALGmiZfu7CAH4rXhgtRTLTxftemlI0sWmxmc=
 google.golang.org/grpc v1.16.0 h1:dz5IJGuC2BB7qXR5AyHNwAUBhZscK2xVez7mznh72sY=
 google.golang.org/grpc v1.16.0/go.mod h1:0JHn/cJsOMiMfNA9+DeHDlAU7KAAB5GDlYFpa9MZMio=
-gopkg.in/airbrake/gobrake.v2 v2.0.9/go.mod h1:/h5ZAUhDkGaJfjzjKLSjv6zCL6O0LLBxU4K+aSYdM/U=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127 h1:qIbj1fsPNlZgppZ+VLlY7N33q108Sa+fhmuc+sWQYwY=
-gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/fsnotify.v1 v1.4.7 h1:xOHLXZwVvI9hhs+cLKq5+I5onOuwQLhQwiu63xxlHs4=
 gopkg.in/fsnotify.v1 v1.4.7/go.mod h1:Tz8NjZHkW78fSQdbUxIjBTcgA1z1m8ZHf0WmKUhAMys=
-gopkg.in/gemnasium/logrus-airbrake-hook.v2 v2.1.2/go.mod h1:Xk6kEKp8OKb+X14hQBKWaSkCsqBpgog8nAV2xsGOxlo=
-gopkg.in/mgo.v2 v2.0.0-20180705113604-9856a29383ce h1:xcEWjVhvbDy+nHP67nPDDpbYrY+ILlfndk4bRioVHaU=
-gopkg.in/mgo.v2 v2.0.0-20180705113604-9856a29383ce/go.mod h1:yeKp02qBN3iKW1OzL3MGk2IdtZzaj7SFntXj72NppTA=
 gopkg.in/natefinch/lumberjack.v2 v2.0.0 h1:1Lc07Kr7qY4U2YPouBjpCLxpiyxIVoxqXgkXLknAOE8=
 gopkg.in/natefinch/lumberjack.v2 v2.0.0/go.mod h1:l0ndWWf7gzL7RNwBG7wST/UCcT4T24xpD6X8LsfU/+k=
 gopkg.in/stretchr/testify.v1 v1.2.2 h1:yhQC6Uy5CqibAIlk1wlusa/MJ3iAN49/BsR/dCCKz3M=
@@ -287,6 +211,6 @@ gopkg.in/tomb.v1 v1.0.0-20141024135613-dd632973f1e7/go.mod h1:dt/ZhP58zS4L8KSrWD
 gopkg.in/yaml.v2 v2.2.1 h1:mUhvW9EsL+naU5Q3cakzfE91YhliOondGd6ZrsDBHQE=
 gopkg.in/yaml.v2 v2.2.1/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 honnef.co/go/tools v0.0.0-20180728063816-88497007e858/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
-honnef.co/go/tools v0.0.0-20180920025451-e3ad64cb4ed3/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
+sourcegraph.com/sourcegraph/appdash v0.0.0-20180531100431-4c381bd170b4 h1:VO9oZbbkvTwqLimlQt15QNdOOBArT2dw/bvzsMZBiqQ=
 sourcegraph.com/sourcegraph/appdash v0.0.0-20180531100431-4c381bd170b4/go.mod h1:hI742Nqp5OhwiqlzhgfbWU4mW4yO10fP+LoT9WOswdU=
 sourcegraph.com/sourcegraph/appdash-data v0.0.0-20151005221446-73f23eafcf67/go.mod h1:L5q+DGLGOQFpo1snNEkLOJT2d1YTW66rWNzatr3He1k=
diff --git a/vendor/github.com/pingcap/parser/model/model.go b/vendor/github.com/pingcap/parser/model/model.go
index 958a29f83278f4058e69fbe6b4c795904afb0655..a5ebab0ebb98d37575f001783befa4bb5358f5b6 100644
--- a/vendor/github.com/pingcap/parser/model/model.go
+++ b/vendor/github.com/pingcap/parser/model/model.go
@@ -250,6 +250,14 @@ func (t *TableInfo) GetAutoIncrementColInfo() *ColumnInfo {
 	return nil
 }
 
+func (t *TableInfo) IsAutoIncColUnsigned() bool {
+	col := t.GetAutoIncrementColInfo()
+	if col == nil {
+		return false
+	}
+	return mysql.HasUnsignedFlag(col.Flag)
+}
+
 // Cols returns the columns of the table in public state.
 func (t *TableInfo) Cols() []*ColumnInfo {
 	publicColumns := make([]*ColumnInfo, len(t.Columns))
diff --git a/vendor/github.com/pingcap/parser/opcode/opcode.go b/vendor/github.com/pingcap/parser/opcode/opcode.go
index 670fb2b883bd14afd87ded2fb3c21ad3d4348d17..0b2a1936df67318268ce3d3def32a632dfa6cf36 100644
--- a/vendor/github.com/pingcap/parser/opcode/opcode.go
+++ b/vendor/github.com/pingcap/parser/opcode/opcode.go
@@ -16,6 +16,8 @@ package opcode
 import (
 	"fmt"
 	"io"
+
+	"github.com/pingcap/errors"
 )
 
 // Op is opcode type.
@@ -136,3 +138,12 @@ var opsLiteral = map[Op]string{
 func (o Op) Format(w io.Writer) {
 	fmt.Fprintf(w, "%s", opsLiteral[o])
 }
+
+// Restore the Op into a Writer
+func (o Op) Restore(w io.Writer) error {
+	if v, ok := opsLiteral[o]; ok {
+		fmt.Fprint(w, v)
+		return nil
+	}
+	return errors.Errorf("Invalid opcode type %d during restoring AST to SQL text", o)
+}
diff --git a/vendor/github.com/pingcap/tidb/types/field_type.go b/vendor/github.com/pingcap/tidb/types/field_type.go
index 602c27ca9a34f895ad9b17b793ca48a79f677e3f..2178f6ed9a7230a4acb1da668998971f85156221 100644
--- a/vendor/github.com/pingcap/tidb/types/field_type.go
+++ b/vendor/github.com/pingcap/tidb/types/field_type.go
@@ -128,12 +128,24 @@ func DefaultParamTypeForValue(value interface{}, tp *FieldType) {
 		tp.Decimal = UnspecifiedLength
 	default:
 		DefaultTypeForValue(value, tp)
+		if hasVariantFieldLength(tp) {
+			tp.Flen = UnspecifiedLength
+		}
 		if tp.Tp == mysql.TypeUnspecified {
 			tp.Tp = mysql.TypeVarString
 		}
 	}
 }
 
+func hasVariantFieldLength(tp *FieldType) bool {
+	switch tp.Tp {
+	case mysql.TypeLonglong, mysql.TypeVarString, mysql.TypeDouble, mysql.TypeBlob,
+		mysql.TypeBit, mysql.TypeDuration, mysql.TypeNewDecimal, mysql.TypeEnum, mysql.TypeSet:
+		return true
+	}
+	return false
+}
+
 // DefaultTypeForValue returns the default FieldType for the value.
 func DefaultTypeForValue(value interface{}, tp *FieldType) {
 	switch x := value.(type) {
diff --git a/vendor/github.com/pingcap/tidb/types/parser_driver/value_expr.go b/vendor/github.com/pingcap/tidb/types/parser_driver/value_expr.go
index 0e83711912ceb4c420b7a3696a286927214127fc..08b6872ce2f21cac8ae2a7ca1bd58d0b94ed2e97 100644
--- a/vendor/github.com/pingcap/tidb/types/parser_driver/value_expr.go
+++ b/vendor/github.com/pingcap/tidb/types/parser_driver/value_expr.go
@@ -17,7 +17,6 @@ import (
 	"fmt"
 	"io"
 	"strconv"
-	"strings"
 
 	"github.com/pingcap/errors"
 	"github.com/pingcap/parser/ast"
@@ -69,11 +68,45 @@ type ValueExpr struct {
 	projectionOffset int
 }
 
-// Restore implements Recoverable interface.
-func (n *ValueExpr) Restore(sb *strings.Builder) error {
-	err := n.format(sb)
-	if err != nil {
-		return errors.Trace(err)
+// Restore implements Node interface.
+func (n *ValueExpr) Restore(ctx *ast.RestoreCtx) error {
+	switch n.Kind() {
+	case types.KindNull:
+		ctx.WriteKeyWord("NULL")
+	case types.KindInt64:
+		if n.Type.Flag&mysql.IsBooleanFlag != 0 {
+			if n.GetInt64() > 0 {
+				ctx.WriteKeyWord("TRUE")
+			} else {
+				ctx.WriteKeyWord("FALSE")
+			}
+		} else {
+			ctx.WritePlain(strconv.FormatInt(n.GetInt64(), 10))
+		}
+	case types.KindUint64:
+		ctx.WritePlain(strconv.FormatUint(n.GetUint64(), 10))
+	case types.KindFloat32:
+		ctx.WritePlain(strconv.FormatFloat(n.GetFloat64(), 'e', -1, 32))
+	case types.KindFloat64:
+		ctx.WritePlain(strconv.FormatFloat(n.GetFloat64(), 'e', -1, 64))
+	case types.KindString, types.KindBytes:
+		ctx.WriteString(n.GetString())
+	case types.KindMysqlDecimal:
+		ctx.WritePlain(n.GetMysqlDecimal().String())
+	case types.KindBinaryLiteral:
+		if n.Type.Flag&mysql.UnsignedFlag != 0 {
+			ctx.WritePlainf("x'%x'", n.GetBytes())
+		} else {
+			ctx.WritePlain(n.GetBinaryLiteral().ToBitLiteralString(true))
+		}
+	case types.KindMysqlDuration, types.KindMysqlEnum,
+		types.KindMysqlBit, types.KindMysqlSet, types.KindMysqlTime,
+		types.KindInterface, types.KindMinNotNull, types.KindMaxValue,
+		types.KindRaw, types.KindMysqlJSON:
+		// TODO implement Restore function
+		return errors.New("Not implemented")
+	default:
+		return errors.New("can't format to string")
 	}
 	return nil
 }
@@ -84,7 +117,7 @@ func (n *ValueExpr) GetDatumString() string {
 }
 
 // Format the ExprNode into a Writer.
-func (n *ValueExpr) format(w io.Writer) error {
+func (n *ValueExpr) Format(w io.Writer) {
 	var s string
 	switch n.Kind() {
 	case types.KindNull:
@@ -116,18 +149,9 @@ func (n *ValueExpr) format(w io.Writer) error {
 			s = n.GetBinaryLiteral().ToBitLiteralString(true)
 		}
 	default:
-		return errors.New("can't format to string")
-	}
-	fmt.Fprint(w, s)
-	return nil
-}
-
-// Format the ExprNode into a Writer.
-func (n *ValueExpr) Format(w io.Writer) {
-	err := n.format(w)
-	if err != nil {
 		panic("Can't format to string")
 	}
+	fmt.Fprint(w, s)
 }
 
 // newValueExpr creates a ValueExpr with value, and sets default field type.
@@ -170,9 +194,9 @@ type ParamMarkerExpr struct {
 	Order  int
 }
 
-// Restore implements Recoverable interface.
-func (n *ParamMarkerExpr) Restore(sb *strings.Builder) error {
-	sb.WriteString("?")
+// Restore implements Node interface.
+func (n *ParamMarkerExpr) Restore(ctx *ast.RestoreCtx) error {
+	ctx.WritePlain("?")
 	return nil
 }
 
diff --git a/vendor/vendor.json b/vendor/vendor.json
index d8fbea1f3a49162f3585cdee9769f5cf8ed45096..f60b573026894719126ab1cf70a60d90384b61e4 100644
--- a/vendor/vendor.json
+++ b/vendor/vendor.json
@@ -105,106 +105,106 @@
 			"revisionTime": "2018-10-24T15:10:47Z"
 		},
 		{
-			"checksumSHA1": "xbV0lm0Qw8rFC82Dttxbf5ypBjA=",
+			"checksumSHA1": "fjZ4hf54cBBlV260wsAMZJ5T3po=",
 			"path": "github.com/pingcap/parser",
-			"revision": "f20218bc290343c2752c4926c1bf4264343bbef4",
-			"revisionTime": "2018-12-12T04:21:31Z"
+			"revision": "b7f4816358997259f649a06fd126db3542b644c8",
+			"revisionTime": "2018-12-17T08:17:10Z"
 		},
 		{
-			"checksumSHA1": "RosqMriA/39ZEtqGgNU+bOfRBVc=",
+			"checksumSHA1": "nRo2Z/Gyb1ziK+CKQi1OAOMa4hc=",
 			"path": "github.com/pingcap/parser/ast",
-			"revision": "f20218bc290343c2752c4926c1bf4264343bbef4",
-			"revisionTime": "2018-12-12T04:21:31Z"
+			"revision": "b7f4816358997259f649a06fd126db3542b644c8",
+			"revisionTime": "2018-12-17T08:17:10Z"
 		},
 		{
 			"checksumSHA1": "skWGV4FNvD3vr+5olepaPPnylUw=",
 			"path": "github.com/pingcap/parser/auth",
-			"revision": "f20218bc290343c2752c4926c1bf4264343bbef4",
-			"revisionTime": "2018-12-12T04:21:31Z"
+			"revision": "b7f4816358997259f649a06fd126db3542b644c8",
+			"revisionTime": "2018-12-17T08:17:10Z"
 		},
 		{
 			"checksumSHA1": "t4UHo966WzU9Z0IJkyGHRp0loOk=",
 			"path": "github.com/pingcap/parser/charset",
-			"revision": "f20218bc290343c2752c4926c1bf4264343bbef4",
-			"revisionTime": "2018-12-12T04:21:31Z"
+			"revision": "b7f4816358997259f649a06fd126db3542b644c8",
+			"revisionTime": "2018-12-17T08:17:10Z"
 		},
 		{
 			"checksumSHA1": "SInoXbsRe0tnBwmatmtZYfSFbdk=",
 			"path": "github.com/pingcap/parser/format",
-			"revision": "f20218bc290343c2752c4926c1bf4264343bbef4",
-			"revisionTime": "2018-12-12T04:21:31Z"
+			"revision": "b7f4816358997259f649a06fd126db3542b644c8",
+			"revisionTime": "2018-12-17T08:17:10Z"
 		},
 		{
-			"checksumSHA1": "reRV2qecd6NpB7tIW3JeK46K/sk=",
+			"checksumSHA1": "WZYTGDMnc1UfTdjdZoBbISsnpRY=",
 			"path": "github.com/pingcap/parser/model",
-			"revision": "f20218bc290343c2752c4926c1bf4264343bbef4",
-			"revisionTime": "2018-12-12T04:21:31Z"
+			"revision": "b7f4816358997259f649a06fd126db3542b644c8",
+			"revisionTime": "2018-12-17T08:17:10Z"
 		},
 		{
 			"checksumSHA1": "QBa9yiMDQNl2cLLwqlRoNTpCPNg=",
 			"path": "github.com/pingcap/parser/mysql",
-			"revision": "f20218bc290343c2752c4926c1bf4264343bbef4",
-			"revisionTime": "2018-12-12T04:21:31Z"
+			"revision": "b7f4816358997259f649a06fd126db3542b644c8",
+			"revisionTime": "2018-12-17T08:17:10Z"
 		},
 		{
-			"checksumSHA1": "oNBCSwJRykKuzIKgPCttatB9hAo=",
+			"checksumSHA1": "+O6CYIE0jT8pIDxWRP9FtKwFZjI=",
 			"path": "github.com/pingcap/parser/opcode",
-			"revision": "f20218bc290343c2752c4926c1bf4264343bbef4",
-			"revisionTime": "2018-12-12T04:21:31Z"
+			"revision": "b7f4816358997259f649a06fd126db3542b644c8",
+			"revisionTime": "2018-12-17T08:17:10Z"
 		},
 		{
 			"checksumSHA1": "XvnUllvwMYd6HrMvMiKnn4cGN2M=",
 			"path": "github.com/pingcap/parser/terror",
-			"revision": "f20218bc290343c2752c4926c1bf4264343bbef4",
-			"revisionTime": "2018-12-12T04:21:31Z"
+			"revision": "b7f4816358997259f649a06fd126db3542b644c8",
+			"revisionTime": "2018-12-17T08:17:10Z"
 		},
 		{
 			"checksumSHA1": "YoDiJ3sniNqxkP5X/BDkx6efteA=",
 			"path": "github.com/pingcap/parser/types",
-			"revision": "f20218bc290343c2752c4926c1bf4264343bbef4",
-			"revisionTime": "2018-12-12T04:21:31Z"
+			"revision": "b7f4816358997259f649a06fd126db3542b644c8",
+			"revisionTime": "2018-12-17T08:17:10Z"
 		},
 		{
 			"checksumSHA1": "fWqL/7jTYOiqDNmiUcQi3u45Hw0=",
 			"path": "github.com/pingcap/tidb/sessionctx/stmtctx",
-			"revision": "4ccd7456fcdc5e62e68f49a0a542cbcf88e38343",
-			"revisionTime": "2018-12-13T09:52:39Z"
+			"revision": "ab88f0b1c3b6db829f3e553963673a9bf7752899",
+			"revisionTime": "2018-12-17T12:08:05Z"
 		},
 		{
-			"checksumSHA1": "0CCq+3fAyaXs9XU+xWaRvbbtSOQ=",
+			"checksumSHA1": "kXyszfR2fQ6bHvuCCFlHRkt1mF0=",
 			"path": "github.com/pingcap/tidb/types",
-			"revision": "4ccd7456fcdc5e62e68f49a0a542cbcf88e38343",
-			"revisionTime": "2018-12-13T09:52:39Z"
+			"revision": "ab88f0b1c3b6db829f3e553963673a9bf7752899",
+			"revisionTime": "2018-12-17T12:08:05Z"
 		},
 		{
 			"checksumSHA1": "DWVD7+ygtT66IQ+cqXmMJ5OVqUk=",
 			"path": "github.com/pingcap/tidb/types/json",
-			"revision": "4ccd7456fcdc5e62e68f49a0a542cbcf88e38343",
-			"revisionTime": "2018-12-13T09:52:39Z"
+			"revision": "ab88f0b1c3b6db829f3e553963673a9bf7752899",
+			"revisionTime": "2018-12-17T12:08:05Z"
 		},
 		{
-			"checksumSHA1": "Zp5ME8OXNTmHnYTwJJUZlydN4/U=",
+			"checksumSHA1": "6vi/eCZXqNTa5eAUpxDZet4LPlY=",
 			"path": "github.com/pingcap/tidb/types/parser_driver",
-			"revision": "4ccd7456fcdc5e62e68f49a0a542cbcf88e38343",
-			"revisionTime": "2018-12-13T09:52:39Z"
+			"revision": "ab88f0b1c3b6db829f3e553963673a9bf7752899",
+			"revisionTime": "2018-12-17T12:08:05Z"
 		},
 		{
 			"checksumSHA1": "s709bhSrG2Ec35406mGtrySid4s=",
 			"path": "github.com/pingcap/tidb/util/execdetails",
-			"revision": "4ccd7456fcdc5e62e68f49a0a542cbcf88e38343",
-			"revisionTime": "2018-12-13T09:52:39Z"
+			"revision": "ab88f0b1c3b6db829f3e553963673a9bf7752899",
+			"revisionTime": "2018-12-17T12:08:05Z"
 		},
 		{
 			"checksumSHA1": "nUC7zVoAMNR2a+z2iGqHoN2AkFE=",
 			"path": "github.com/pingcap/tidb/util/hack",
-			"revision": "4ccd7456fcdc5e62e68f49a0a542cbcf88e38343",
-			"revisionTime": "2018-12-13T09:52:39Z"
+			"revision": "ab88f0b1c3b6db829f3e553963673a9bf7752899",
+			"revisionTime": "2018-12-17T12:08:05Z"
 		},
 		{
 			"checksumSHA1": "xSyepiuqsoaaeDch7cXeumvVHKM=",
 			"path": "github.com/pingcap/tidb/util/memory",
-			"revision": "4ccd7456fcdc5e62e68f49a0a542cbcf88e38343",
-			"revisionTime": "2018-12-13T09:52:39Z"
+			"revision": "ab88f0b1c3b6db829f3e553963673a9bf7752899",
+			"revisionTime": "2018-12-17T12:08:05Z"
 		},
 		{
 			"checksumSHA1": "SmYeIK/fIYXNu8IKxD6HOVQVTuU=",
@@ -401,62 +401,62 @@
 		{
 			"checksumSHA1": "aKn1oKcY74N8TRLm3Ayt7Q4bbI4=",
 			"path": "vitess.io/vitess/go/bytes2",
-			"revision": "eb5a5e0e435db30856600b794d8cff235fdf24b7",
-			"revisionTime": "2018-12-13T22:28:01Z"
+			"revision": "935bf8ac1ad1e75bc8fd26a74fbfc906f15aa7d0",
+			"revisionTime": "2018-12-17T04:01:44Z"
 		},
 		{
 			"checksumSHA1": "JVCEN4UGRmg3TofIBdzZMZ3G0Ww=",
 			"path": "vitess.io/vitess/go/hack",
-			"revision": "eb5a5e0e435db30856600b794d8cff235fdf24b7",
-			"revisionTime": "2018-12-13T22:28:01Z"
+			"revision": "935bf8ac1ad1e75bc8fd26a74fbfc906f15aa7d0",
+			"revisionTime": "2018-12-17T04:01:44Z"
 		},
 		{
-			"checksumSHA1": "e1WJ7vCnVrlQQQlc6n/FewCDMso=",
+			"checksumSHA1": "F5pcGq+2W1FHEjgktTdKOE6W8mk=",
 			"path": "vitess.io/vitess/go/sqltypes",
-			"revision": "eb5a5e0e435db30856600b794d8cff235fdf24b7",
-			"revisionTime": "2018-12-13T22:28:01Z"
+			"revision": "935bf8ac1ad1e75bc8fd26a74fbfc906f15aa7d0",
+			"revisionTime": "2018-12-17T04:01:44Z"
 		},
 		{
 			"checksumSHA1": "ntFIQYkBS51G6y+FEkjFW40+HOU=",
 			"path": "vitess.io/vitess/go/vt/log",
-			"revision": "eb5a5e0e435db30856600b794d8cff235fdf24b7",
-			"revisionTime": "2018-12-13T22:28:01Z"
+			"revision": "935bf8ac1ad1e75bc8fd26a74fbfc906f15aa7d0",
+			"revisionTime": "2018-12-17T04:01:44Z"
 		},
 		{
 			"checksumSHA1": "tPQFPwbMdjuX0qjNl4Zl8zc37JQ=",
 			"path": "vitess.io/vitess/go/vt/proto/query",
-			"revision": "eb5a5e0e435db30856600b794d8cff235fdf24b7",
-			"revisionTime": "2018-12-13T22:28:01Z"
+			"revision": "935bf8ac1ad1e75bc8fd26a74fbfc906f15aa7d0",
+			"revisionTime": "2018-12-17T04:01:44Z"
 		},
 		{
 			"checksumSHA1": "o0tR/c7lgr0pLkxk7CdvjiNDAKU=",
 			"path": "vitess.io/vitess/go/vt/proto/topodata",
-			"revision": "eb5a5e0e435db30856600b794d8cff235fdf24b7",
-			"revisionTime": "2018-12-13T22:28:01Z"
+			"revision": "935bf8ac1ad1e75bc8fd26a74fbfc906f15aa7d0",
+			"revisionTime": "2018-12-17T04:01:44Z"
 		},
 		{
 			"checksumSHA1": "77UojBqi0yyeQvR70j7C3kcKclQ=",
 			"path": "vitess.io/vitess/go/vt/proto/vtgate",
-			"revision": "eb5a5e0e435db30856600b794d8cff235fdf24b7",
-			"revisionTime": "2018-12-13T22:28:01Z"
+			"revision": "935bf8ac1ad1e75bc8fd26a74fbfc906f15aa7d0",
+			"revisionTime": "2018-12-17T04:01:44Z"
 		},
 		{
 			"checksumSHA1": "QpWGhoVDwM+8+sgYLI/YU+95iGU=",
 			"path": "vitess.io/vitess/go/vt/proto/vtrpc",
-			"revision": "eb5a5e0e435db30856600b794d8cff235fdf24b7",
-			"revisionTime": "2018-12-13T22:28:01Z"
+			"revision": "935bf8ac1ad1e75bc8fd26a74fbfc906f15aa7d0",
+			"revisionTime": "2018-12-17T04:01:44Z"
 		},
 		{
 			"checksumSHA1": "lENrUY/YyxwYFHYN+21TBH92P3U=",
 			"path": "vitess.io/vitess/go/vt/sqlparser",
-			"revision": "eb5a5e0e435db30856600b794d8cff235fdf24b7",
-			"revisionTime": "2018-12-13T22:28:01Z"
+			"revision": "935bf8ac1ad1e75bc8fd26a74fbfc906f15aa7d0",
+			"revisionTime": "2018-12-17T04:01:44Z"
 		},
 		{
-			"checksumSHA1": "oF4XzuOzwvj1iduX/lYqNSyY/HM=",
+			"checksumSHA1": "Jx+gOh/kiBDSZxEIWHyYn9brjdo=",
 			"path": "vitess.io/vitess/go/vt/vterrors",
-			"revision": "eb5a5e0e435db30856600b794d8cff235fdf24b7",
-			"revisionTime": "2018-12-13T22:28:01Z"
+			"revision": "935bf8ac1ad1e75bc8fd26a74fbfc906f15aa7d0",
+			"revisionTime": "2018-12-17T04:01:44Z"
 		}
 	],
 	"rootPath": "github.com/XiaoMi/soar"
diff --git a/vendor/vitess.io/vitess/go/sqltypes/query_response.go b/vendor/vitess.io/vitess/go/sqltypes/query_response.go
index eeca6cd6c55f58033087535ca85f640ab0a1ad99..5ce8e58b7653a35ca4fa301c57fcc0b7b4f2911e 100644
--- a/vendor/vitess.io/vitess/go/sqltypes/query_response.go
+++ b/vendor/vitess.io/vitess/go/sqltypes/query_response.go
@@ -16,7 +16,9 @@ limitations under the License.
 
 package sqltypes
 
-import "reflect"
+import (
+	"vitess.io/vitess/go/vt/vterrors"
+)
 
 // QueryResponse represents a query response for ExecuteBatch.
 type QueryResponse struct {
@@ -34,7 +36,7 @@ func QueryResponsesEqual(r1, r2 []QueryResponse) bool {
 		if !r.QueryResult.Equal(r2[i].QueryResult) {
 			return false
 		}
-		if !reflect.DeepEqual(r.QueryError, r2[i].QueryError) {
+		if !vterrors.Equals(r.QueryError, r2[i].QueryError) {
 			return false
 		}
 	}
diff --git a/vendor/vitess.io/vitess/go/vt/vterrors/LICENSE b/vendor/vitess.io/vitess/go/vt/vterrors/LICENSE
new file mode 100644
index 0000000000000000000000000000000000000000..835ba3e755cef8c0dde475f1ebfd41e4ba0c79bf
--- /dev/null
+++ b/vendor/vitess.io/vitess/go/vt/vterrors/LICENSE
@@ -0,0 +1,23 @@
+Copyright (c) 2015, Dave Cheney <dave@cheney.net>
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+* Redistributions of source code must retain the above copyright notice, this
+  list of conditions and the following disclaimer.
+
+* Redistributions in binary form must reproduce the above copyright notice,
+  this list of conditions and the following disclaimer in the documentation
+  and/or other materials provided with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/vendor/vitess.io/vitess/go/vt/vterrors/doc.go b/vendor/vitess.io/vitess/go/vt/vterrors/doc.go
deleted file mode 100644
index a704cc6568b60baf0ff0ab06c439735a5055b8bc..0000000000000000000000000000000000000000
--- a/vendor/vitess.io/vitess/go/vt/vterrors/doc.go
+++ /dev/null
@@ -1,44 +0,0 @@
-/*
-Copyright 2017 Google Inc.
-
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-Unless required by applicable law or agreedto in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
-*/
-
-// Package vterrors provides helpers for propagating internal errors
-// through the Vitess system (including across RPC boundaries) in a
-// structured way.
-package vterrors
-
-/*
-
-Vitess uses canonical error codes for error reporting. This is based
-on years of industry experience with error reporting. This idea is
-that errors should be classified into a small set of errors (10 or so)
-with very specific meaning. Each error has a code, and a message. When
-errors are passed around (even through RPCs), the code is
-propagated. To handle errors, only the code should be looked at (and
-not string-matching on the error message).
-
-Vitess defines the error codes in /proto/vtrpc.proto. Along with an
-RPCError message that can be used to transmit errors through RPCs, in
-the message payloads. These codes match the names and numbers defined
-by gRPC.
-
-Vitess also defines a standardized error implementation that allows
-you to build an error with an associated canonical code.
-
-While sending an error through gRPC, these codes are transmitted
-using gRPC's error propagation mechanism and decoded back to
-the original code on the other end.
-
-*/
diff --git a/vendor/vitess.io/vitess/go/vt/vterrors/stack.go b/vendor/vitess.io/vitess/go/vt/vterrors/stack.go
new file mode 100644
index 0000000000000000000000000000000000000000..2ba717ad3f0489116f646a08cfdcdeecf347c5b9
--- /dev/null
+++ b/vendor/vitess.io/vitess/go/vt/vterrors/stack.go
@@ -0,0 +1,191 @@
+package vterrors
+
+/* This file is copied from https://github.com/pkg/errors/blob/v0.8.0/stack.go */
+
+import (
+	"fmt"
+	"io"
+	"path"
+	"runtime"
+	"strings"
+)
+
+// Frame represents a program counter inside a stack frame.
+type Frame uintptr
+
+// pc returns the program counter for this frame;
+// multiple frames may have the same PC value.
+func (f Frame) pc() uintptr { return uintptr(f) - 1 }
+
+// file returns the full path to the file that contains the
+// function for this Frame's pc.
+func (f Frame) file() string {
+	fn := runtime.FuncForPC(f.pc())
+	if fn == nil {
+		return "unknown"
+	}
+	file, _ := fn.FileLine(f.pc())
+	return file
+}
+
+// line returns the line number of source code of the
+// function for this Frame's pc.
+func (f Frame) line() int {
+	fn := runtime.FuncForPC(f.pc())
+	if fn == nil {
+		return 0
+	}
+	_, line := fn.FileLine(f.pc())
+	return line
+}
+
+// Format formats the frame according to the fmt.Formatter interface.
+//
+//    %s    source file
+//    %d    source line
+//    %n    function name
+//    %v    equivalent to %s:%d
+//
+// Format accepts flags that alter the printing of some verbs, as follows:
+//
+//    %+s   path of source file relative to the compile time GOPATH
+//    %+v   equivalent to %+s:%d
+func (f Frame) Format(s fmt.State, verb rune) {
+	switch verb {
+	case 's':
+		switch {
+		case s.Flag('+'):
+			pc := f.pc()
+			fn := runtime.FuncForPC(pc)
+			if fn == nil {
+				io.WriteString(s, "unknown")
+			} else {
+				file, _ := fn.FileLine(pc)
+				fmt.Fprintf(s, "%s\n\t%s", fn.Name(), file)
+			}
+		default:
+			io.WriteString(s, path.Base(f.file()))
+		}
+	case 'd':
+		fmt.Fprintf(s, "%d", f.line())
+	case 'n':
+		name := runtime.FuncForPC(f.pc()).Name()
+		io.WriteString(s, funcname(name))
+	case 'v':
+		f.Format(s, 's')
+		io.WriteString(s, ":")
+		f.Format(s, 'd')
+	}
+}
+
+// StackTrace is stack of Frames from innermost (newest) to outermost (oldest).
+type StackTrace []Frame
+
+// Format format the stacktrace according to the fmt.Formatter interface.
+//
+//    %s    source file
+//    %d    source line
+//    %n    function name
+//    %v    equivalent to %s:%d
+//
+// Format accepts flags that alter the printing of some verbs, as follows:
+//
+//    %+s   path of source file relative to the compile time GOPATH
+//    %+v   equivalent to %+s:%d
+func (st StackTrace) Format(s fmt.State, verb rune) {
+	switch verb {
+	case 'v':
+		switch {
+		case s.Flag('+'):
+			for _, f := range st {
+				fmt.Fprintf(s, "\n%+v", f)
+			}
+		case s.Flag('#'):
+			fmt.Fprintf(s, "%#v", []Frame(st))
+		default:
+			fmt.Fprintf(s, "%v", []Frame(st))
+		}
+	case 's':
+		fmt.Fprintf(s, "%s", []Frame(st))
+	}
+}
+
+// stack represents a stack of program counters.
+type stack []uintptr
+
+func (s *stack) Format(st fmt.State, verb rune) {
+	switch verb {
+	case 'v':
+		switch {
+		case st.Flag('+'):
+			for _, pc := range *s {
+				f := Frame(pc)
+				fmt.Fprintf(st, "\n%+v", f)
+			}
+		}
+	}
+}
+
+func (s *stack) StackTrace() StackTrace {
+	f := make([]Frame, len(*s))
+	for i := 0; i < len(f); i++ {
+		f[i] = Frame((*s)[i])
+	}
+	return f
+}
+
+func callers() *stack {
+	const depth = 32
+	var pcs [depth]uintptr
+	n := runtime.Callers(3, pcs[:])
+	var st stack = pcs[0:n]
+	return &st
+}
+
+// funcname removes the path prefix component of a function's name reported by func.Name().
+func funcname(name string) string {
+	i := strings.LastIndex(name, "/")
+	name = name[i+1:]
+	i = strings.Index(name, ".")
+	return name[i+1:]
+}
+
+func trimGOPATH(name, file string) string {
+	// Here we want to get the source file path relative to the compile time
+	// GOPATH. As of Go 1.6.x there is no direct way to know the compiled
+	// GOPATH at runtime, but we can infer the number of path segments in the
+	// GOPATH. We note that fn.Name() returns the function name qualified by
+	// the import path, which does not include the GOPATH. Thus we can trim
+	// segments from the beginning of the file path until the number of path
+	// separators remaining is one more than the number of path separators in
+	// the function name. For example, given:
+	//
+	//    GOPATH     /home/user
+	//    file       /home/user/src/pkg/sub/file.go
+	//    fn.Name()  pkg/sub.Type.Method
+	//
+	// We want to produce:
+	//
+	//    pkg/sub/file.go
+	//
+	// From this we can easily see that fn.Name() has one less path separator
+	// than our desired output. We count separators from the end of the file
+	// path until it finds two more than in the function name and then move
+	// one character forward to preserve the initial path segment without a
+	// leading separator.
+	const sep = "/"
+	goal := strings.Count(name, sep) + 2
+	i := len(file)
+	for n := 0; n < goal; n++ {
+		i = strings.LastIndex(file[:i], sep)
+		if i == -1 {
+			// not enough separators found, set i so that the slice expression
+			// below leaves file unmodified
+			i = -len(sep)
+			break
+		}
+	}
+	// get back to 0 or trim the leading separator
+	file = file[i+len(sep):]
+	return file
+}
diff --git a/vendor/vitess.io/vitess/go/vt/vterrors/vterrors.go b/vendor/vitess.io/vitess/go/vt/vterrors/vterrors.go
index 2ce2416041017aa5792904aa7d025246336dfdc6..6e85542cb101dbba81c400208e02dca984869c96 100644
--- a/vendor/vitess.io/vitess/go/vt/vterrors/vterrors.go
+++ b/vendor/vitess.io/vitess/go/vt/vterrors/vterrors.go
@@ -1,73 +1,153 @@
-/*
-Copyright 2017 Google Inc.
-
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-Unless required by applicable law or agreedto in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
-*/
-
+// Package vterrors provides simple error handling primitives for Vitess
+//
+// In all Vitess code, errors should be propagated using vterrors.Wrapf()
+// and not fmt.Errorf().
+//
+// New errors should be created using vterrors.New
+//
+// Vitess uses canonical error codes for error reporting. This is based
+// on years of industry experience with error reporting. This idea is
+// that errors should be classified into a small set of errors (10 or so)
+// with very specific meaning. Each error has a code, and a message. When
+// errors are passed around (even through RPCs), the code is
+// propagated. To handle errors, only the code should be looked at (and
+// not string-matching on the error message).
+//
+// Error codes are defined in /proto/vtrpc.proto. Along with an
+// RPCError message that can be used to transmit errors through RPCs, in
+// the message payloads. These codes match the names and numbers defined
+// by gRPC.
+//
+// A standardized error implementation that allows you to build an error
+// with an associated canonical code is also defined.
+// While sending an error through gRPC, these codes are transmitted
+// using gRPC's error propagation mechanism and decoded back to
+// the original code on the other end.
+//
+// Retrieving the cause of an error
+//
+// Using vterrors.Wrap constructs a stack of errors, adding context to the
+// preceding error. Depending on the nature of the error it may be necessary
+// to reverse the operation of errors.Wrap to retrieve the original error
+// for inspection. Any error value which implements this interface
+//
+//     type causer interface {
+//             Cause() error
+//     }
+//
+// can be inspected by vterrors.Cause and vterrors.RootCause.
+//
+// * vterrors.Cause will find the immediate cause if one is available, or nil
+//   if the error is not a `causer` or if no cause is available.
+// * vterrors.RootCause will recursively retrieve
+//   the topmost error which does not implement causer, which is assumed to be
+//   the original cause. For example:
+//
+//     switch err := errors.RootCause(err).(type) {
+//     case *MyError:
+//             // handle specifically
+//     default:
+//             // unknown error
+//     }
+//
+// causer interface is not exported by this package, but is considered a part
+// of stable public API.
+//
+// Formatted printing of errors
+//
+// All error values returned from this package implement fmt.Formatter and can
+// be formatted by the fmt package. The following verbs are supported
+//
+//     %s    print the error. If the error has a Cause it will be
+//           printed recursively
+//     %v    see %s
+//     %+v   extended format. Each Frame of the error's StackTrace will
+//           be printed in detail.
+//
+// Most but not all of the code in this file was originally copied from
+// https://github.com/pkg/errors/blob/v0.8.0/errors.go
 package vterrors
 
 import (
 	"fmt"
-
 	"golang.org/x/net/context"
-
+	"io"
 	vtrpcpb "vitess.io/vitess/go/vt/proto/vtrpc"
 )
 
-type vtError struct {
-	code vtrpcpb.Code
-	err  string
+// New returns an error with the supplied message.
+// New also records the stack trace at the point it was called.
+func New(code vtrpcpb.Code, message string) error {
+	return &fundamental{
+		msg:   message,
+		code:  code,
+		stack: callers(),
+	}
 }
 
-// New creates a new error using the code and input string.
-func New(code vtrpcpb.Code, in string) error {
-	if code == vtrpcpb.Code_OK {
-		panic("OK is an invalid error code; use INTERNAL instead")
-	}
-	return &vtError{
-		code: code,
-		err:  in,
+// NewWithoutCode returns an error when no applicable error code is available
+// It will record the stack trace when creating the error
+func NewWithoutCode(message string) error {
+	return &fundamental{
+		msg:   message,
+		code:  vtrpcpb.Code_UNKNOWN,
+		stack: callers(),
 	}
 }
 
-// Wrap wraps the given error, returning a new error with the given message as a prefix but with the same error code (if err was a vterror) and message of the passed error.
-func Wrap(err error, message string) error {
-	return New(Code(err), fmt.Sprintf("%v: %v", message, err.Error()))
+// Errorf formats according to a format specifier and returns the string
+// as a value that satisfies error.
+// Errorf also records the stack trace at the point it was called.
+func Errorf(code vtrpcpb.Code, format string, args ...interface{}) error {
+	return &fundamental{
+		msg:   fmt.Sprintf(format, args...),
+		code:  code,
+		stack: callers(),
+	}
 }
 
-// Wrapf wraps the given error, returning a new error with the given format string as a prefix but with the same error code (if err was a vterror) and message of the passed error.
-func Wrapf(err error, format string, args ...interface{}) error {
-	return Wrap(err, fmt.Sprintf(format, args...))
+// fundamental is an error that has a message and a stack, but no caller.
+type fundamental struct {
+	msg  string
+	code vtrpcpb.Code
+	*stack
 }
 
-// Errorf returns a new error built using Printf style arguments.
-func Errorf(code vtrpcpb.Code, format string, args ...interface{}) error {
-	return New(code, fmt.Sprintf(format, args...))
-}
+func (f *fundamental) Error() string { return f.msg }
 
-func (e *vtError) Error() string {
-	return e.err
+func (f *fundamental) Format(s fmt.State, verb rune) {
+	switch verb {
+	case 'v':
+		if s.Flag('+') {
+			io.WriteString(s, "Code: "+f.code.String()+"\n")
+			io.WriteString(s, f.msg+"\n")
+			f.stack.Format(s, verb)
+			return
+		}
+		fallthrough
+	case 's':
+		io.WriteString(s, f.msg)
+	case 'q':
+		fmt.Fprintf(s, "%q", f.msg)
+	}
 }
 
 // Code returns the error code if it's a vtError.
-// If err is nil, it returns ok. Otherwise, it returns unknown.
+// If err is nil, it returns ok.
 func Code(err error) vtrpcpb.Code {
 	if err == nil {
 		return vtrpcpb.Code_OK
 	}
-	if err, ok := err.(*vtError); ok {
+	if err, ok := err.(*fundamental); ok {
 		return err.code
 	}
+
+	cause := Cause(err)
+	if cause != err && cause != nil {
+		// If we did not find an error code at the outer level, let's find the cause and check it's code
+		return Code(cause)
+	}
+
 	// Handle some special cases.
 	switch err {
 	case context.Canceled:
@@ -78,16 +158,111 @@ func Code(err error) vtrpcpb.Code {
 	return vtrpcpb.Code_UNKNOWN
 }
 
+// Wrap returns an error annotating err with a stack trace
+// at the point Wrap is called, and the supplied message.
+// If err is nil, Wrap returns nil.
+func Wrap(err error, message string) error {
+	if err == nil {
+		return nil
+	}
+	return &wrapping{
+		cause: err,
+		msg:   message,
+		stack: callers(),
+	}
+}
+
+// Wrapf returns an error annotating err with a stack trace
+// at the point Wrapf is call, and the format specifier.
+// If err is nil, Wrapf returns nil.
+func Wrapf(err error, format string, args ...interface{}) error {
+	if err == nil {
+		return nil
+	}
+	return &wrapping{
+		cause: err,
+		msg:   fmt.Sprintf(format, args...),
+		stack: callers(),
+	}
+}
+
+type wrapping struct {
+	cause error
+	msg   string
+	stack *stack
+}
+
+func (w *wrapping) Error() string { return w.msg + ": " + w.cause.Error() }
+func (w *wrapping) Cause() error  { return w.cause }
+
+func (w *wrapping) Format(s fmt.State, verb rune) {
+	switch verb {
+	case 'v':
+		if s.Flag('+') {
+			fmt.Fprintf(s, "%+v\n", w.Cause())
+			io.WriteString(s, w.msg)
+			w.stack.Format(s, verb)
+			return
+		}
+		fallthrough
+	case 's', 'q':
+		io.WriteString(s, w.Error())
+	}
+}
+
+// RootCause returns the underlying cause of the error, if possible.
+// An error value has a cause if it implements the following
+// interface:
+//
+//     type causer interface {
+//            Cause() error
+//     }
+//
+// If the error does not implement Cause, the original error will
+// be returned. If the error is nil, nil will be returned without further
+// investigation.
+func RootCause(err error) error {
+	for {
+		cause := Cause(err)
+		if cause == nil {
+			return err
+		}
+		err = cause
+	}
+}
+
+//
+// Cause will return the immediate cause, if possible.
+// An error value has a cause if it implements the following
+// interface:
+//
+//     type causer interface {
+//            Cause() error
+//     }
+// If the error does not implement Cause, nil will be returned
+func Cause(err error) error {
+	type causer interface {
+		Cause() error
+	}
+
+	causerObj, ok := err.(causer)
+	if !ok {
+		return nil
+	}
+
+	return causerObj.Cause()
+}
+
 // Equals returns true iff the error message and the code returned by Code()
-// is equal.
+// are equal.
 func Equals(a, b error) bool {
 	if a == nil && b == nil {
 		// Both are nil.
 		return true
 	}
 
-	if a == nil && b != nil || a != nil && b == nil {
-		// One of the two is nil.
+	if a == nil || b == nil {
+		// One of the two is nil, since we know both are not nil.
 		return false
 	}
 
@@ -97,5 +272,5 @@ func Equals(a, b error) bool {
 // Print is meant to print the vtError object in test failures.
 // For comparing two vterrors, use Equals() instead.
 func Print(err error) string {
-	return fmt.Sprintf("%v: %v", Code(err), err.Error())
+	return fmt.Sprintf("%v: %v\n", Code(err), err.Error())
 }