tidb select_into 源码
tidb select_into 代码
文件路径：/executor/select_into.go
// Copyright 2020 PingCAP, 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 agreed to 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 executor
import (
"bufio"
"bytes"
"context"
"math"
"os"
"strconv"
"github.com/pingcap/errors"
"github.com/pingcap/tidb/parser/ast"
"github.com/pingcap/tidb/parser/mysql"
"github.com/pingcap/tidb/types"
"github.com/pingcap/tidb/util/chunk"
)
// SelectIntoExec represents a SelectInto executor.
type SelectIntoExec struct {
baseExecutor
intoOpt *ast.SelectIntoOption
lineBuf []byte
realBuf []byte
fieldBuf []byte
escapeBuf []byte
enclosed bool
writer *bufio.Writer
dstFile *os.File
chk *chunk.Chunk
started bool
}
// Open implements the Executor Open interface.
func (s *SelectIntoExec) Open(ctx context.Context) error {
// only 'select ... into outfile' is supported now
if s.intoOpt.Tp != ast.SelectIntoOutfile {
return errors.New("unsupported SelectInto type")
}
// MySQL-compatible behavior: allow files to be group-readable
f, err := os.OpenFile(s.intoOpt.FileName, os.O_RDWR|os.O_CREATE|os.O_EXCL, 0640) // #nosec G302
if err != nil {
return errors.Trace(err)
}
s.started = true
s.dstFile = f
s.writer = bufio.NewWriter(s.dstFile)
s.chk = newFirstChunk(s.children[0])
s.lineBuf = make([]byte, 0, 1024)
s.fieldBuf = make([]byte, 0, 64)
s.escapeBuf = make([]byte, 0, 64)
return s.baseExecutor.Open(ctx)
}
// Next implements the Executor Next interface.
func (s *SelectIntoExec) Next(ctx context.Context, req *chunk.Chunk) error {
for {
if err := Next(ctx, s.children[0], s.chk); err != nil {
return err
}
if s.chk.NumRows() == 0 {
break
}
if err := s.dumpToOutfile(); err != nil {
return err
}
}
return nil
}
func (s *SelectIntoExec) considerEncloseOpt(et types.EvalType) bool {
return et == types.ETString || et == types.ETDuration ||
et == types.ETTimestamp || et == types.ETDatetime ||
et == types.ETJson
}
func (s *SelectIntoExec) escapeField(f []byte) []byte {
if s.intoOpt.FieldsInfo.Escaped == 0 {
return f
}
s.escapeBuf = s.escapeBuf[:0]
for _, b := range f {
escape := false
switch {
case b == 0:
// we always escape 0
escape = true
b = '0'
case b == s.intoOpt.FieldsInfo.Escaped || b == s.intoOpt.FieldsInfo.Enclosed:
escape = true
case !s.enclosed && len(s.intoOpt.FieldsInfo.Terminated) > 0 && b == s.intoOpt.FieldsInfo.Terminated[0]:
// if field is enclosed, we only escape line terminator, otherwise both field and line terminator will be escaped
escape = true
case len(s.intoOpt.LinesInfo.Terminated) > 0 && b == s.intoOpt.LinesInfo.Terminated[0]:
// we always escape line terminator
escape = true
}
if escape {
s.escapeBuf = append(s.escapeBuf, s.intoOpt.FieldsInfo.Escaped)
}
s.escapeBuf = append(s.escapeBuf, b)
}
return s.escapeBuf
}
func (s *SelectIntoExec) dumpToOutfile() error {
lineTerm := "\n"
if s.intoOpt.LinesInfo.Terminated != "" {
lineTerm = s.intoOpt.LinesInfo.Terminated
}
fieldTerm := "\t"
if s.intoOpt.FieldsInfo.Terminated != "" {
fieldTerm = s.intoOpt.FieldsInfo.Terminated
}
encloseFlag := false
var encloseByte byte
encloseOpt := false
if s.intoOpt.FieldsInfo.Enclosed != byte(0) {
encloseByte = s.intoOpt.FieldsInfo.Enclosed
encloseFlag = true
encloseOpt = s.intoOpt.FieldsInfo.OptEnclosed
}
nullTerm := []byte("\\N")
if s.intoOpt.FieldsInfo.Escaped != byte(0) {
nullTerm[0] = s.intoOpt.FieldsInfo.Escaped
} else {
nullTerm = []byte("NULL")
}
cols := s.children[0].Schema().Columns
for i := 0; i < s.chk.NumRows(); i++ {
row := s.chk.GetRow(i)
s.lineBuf = s.lineBuf[:0]
for j, col := range cols {
if j != 0 {
s.lineBuf = append(s.lineBuf, fieldTerm...)
}
if row.IsNull(j) {
s.lineBuf = append(s.lineBuf, nullTerm...)
continue
}
et := col.GetType().EvalType()
if (encloseFlag && !encloseOpt) ||
(encloseFlag && encloseOpt && s.considerEncloseOpt(et)) {
s.lineBuf = append(s.lineBuf, encloseByte)
s.enclosed = true
} else {
s.enclosed = false
}
s.fieldBuf = s.fieldBuf[:0]
switch col.GetType().GetType() {
case mysql.TypeTiny, mysql.TypeShort, mysql.TypeInt24, mysql.TypeLong, mysql.TypeYear:
s.fieldBuf = strconv.AppendInt(s.fieldBuf, row.GetInt64(j), 10)
case mysql.TypeLonglong:
if mysql.HasUnsignedFlag(col.GetType().GetFlag()) {
s.fieldBuf = strconv.AppendUint(s.fieldBuf, row.GetUint64(j), 10)
} else {
s.fieldBuf = strconv.AppendInt(s.fieldBuf, row.GetInt64(j), 10)
}
case mysql.TypeFloat:
s.realBuf, s.fieldBuf = DumpRealOutfile(s.realBuf, s.fieldBuf, float64(row.GetFloat32(j)), col.RetType)
case mysql.TypeDouble:
s.realBuf, s.fieldBuf = DumpRealOutfile(s.realBuf, s.fieldBuf, row.GetFloat64(j), col.RetType)
case mysql.TypeNewDecimal:
s.fieldBuf = append(s.fieldBuf, row.GetMyDecimal(j).String()...)
case mysql.TypeString, mysql.TypeVarString, mysql.TypeVarchar,
mysql.TypeTinyBlob, mysql.TypeMediumBlob, mysql.TypeLongBlob, mysql.TypeBlob:
s.fieldBuf = append(s.fieldBuf, row.GetBytes(j)...)
case mysql.TypeBit:
// bit value won't be escaped anyway (verified on MySQL, test case added)
s.lineBuf = append(s.lineBuf, row.GetBytes(j)...)
case mysql.TypeDate, mysql.TypeDatetime, mysql.TypeTimestamp:
s.fieldBuf = append(s.fieldBuf, row.GetTime(j).String()...)
case mysql.TypeDuration:
s.fieldBuf = append(s.fieldBuf, row.GetDuration(j, col.GetType().GetDecimal()).String()...)
case mysql.TypeEnum:
s.fieldBuf = append(s.fieldBuf, row.GetEnum(j).String()...)
case mysql.TypeSet:
s.fieldBuf = append(s.fieldBuf, row.GetSet(j).String()...)
case mysql.TypeJSON:
s.fieldBuf = append(s.fieldBuf, row.GetJSON(j).String()...)
}
switch col.GetType().EvalType() {
case types.ETString, types.ETJson:
s.lineBuf = append(s.lineBuf, s.escapeField(s.fieldBuf)...)
default:
s.lineBuf = append(s.lineBuf, s.fieldBuf...)
}
if (encloseFlag && !encloseOpt) ||
(encloseFlag && encloseOpt && s.considerEncloseOpt(et)) {
s.lineBuf = append(s.lineBuf, encloseByte)
}
}
s.lineBuf = append(s.lineBuf, lineTerm...)
if _, err := s.writer.Write(s.lineBuf); err != nil {
return errors.Trace(err)
}
}
s.ctx.GetSessionVars().StmtCtx.AddAffectedRows(uint64(s.chk.NumRows()))
return nil
}
// Close implements the Executor Close interface.
func (s *SelectIntoExec) Close() error {
if !s.started {
return nil
}
err1 := s.writer.Flush()
err2 := s.dstFile.Close()
err3 := s.baseExecutor.Close()
if err1 != nil {
return errors.Trace(err1)
} else if err2 != nil {
return errors.Trace(err2)
}
return err3
}
const (
expFormatBig = 1e15
expFormatSmall = 1e-15
)
// DumpRealOutfile dumps a real number to lineBuf.
func DumpRealOutfile(realBuf, lineBuf []byte, v float64, tp *types.FieldType) ([]byte, []byte) {
prec := types.UnspecifiedLength
if tp.GetDecimal() > 0 && tp.GetDecimal() != mysql.NotFixedDec {
prec = tp.GetDecimal()
}
absV := math.Abs(v)
if prec == types.UnspecifiedLength && (absV >= expFormatBig || (absV != 0 && absV < expFormatSmall)) {
realBuf = strconv.AppendFloat(realBuf[:0], v, 'e', prec, 64)
if idx := bytes.IndexByte(realBuf, '+'); idx != -1 {
lineBuf = append(lineBuf, realBuf[:idx]...)
lineBuf = append(lineBuf, realBuf[idx+1:]...)
} else {
lineBuf = append(lineBuf, realBuf...)
}
} else {
lineBuf = strconv.AppendFloat(lineBuf, v, 'f', prec, 64)
}
return realBuf, lineBuf
}
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