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// Copyright 2016 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,
// See the License for the specific language governing permissions and
// limitations under the License.
package tablecodec
import (
"bytes"
"encoding/binary"
"math"
"time"
"unicode/utf8"
"github.com/pingcap/errors"
"github.com/pingcap/parser/charset"
"github.com/pingcap/parser/model"
"github.com/pingcap/parser/mysql"
"github.com/pingcap/parser/terror"
"github.com/pingcap/tidb/errno"
"github.com/pingcap/tidb/kv"
"github.com/pingcap/tidb/sessionctx/stmtctx"
"github.com/pingcap/tidb/structure"
"github.com/pingcap/tidb/types"
"github.com/pingcap/tidb/util/codec"
"github.com/pingcap/tidb/util/collate"
"github.com/pingcap/tidb/util/dbterror"
"github.com/pingcap/tidb/util/rowcodec"
)
var (
errInvalidKey = dbterror.ClassXEval.NewStd(errno.ErrInvalidKey)
errInvalidRecordKey = dbterror.ClassXEval.NewStd(errno.ErrInvalidRecordKey)
errInvalidIndexKey = dbterror.ClassXEval.NewStd(errno.ErrInvalidIndexKey)
)
var (
tablePrefix = []byte{'t'}
recordPrefixSep = []byte("_r")
indexPrefixSep = []byte("_i")
metaPrefix = []byte{'m'}
)
const (
idLen = 8
prefixLen = 1 + idLen /*tableID*/ + 2
// RecordRowKeyLen is public for calculating avgerage row size.
RecordRowKeyLen = prefixLen + idLen /*handle*/
tablePrefixLength = 1
recordPrefixSepLength = 2
metaPrefixLength = 1
// MaxOldEncodeValueLen is the maximum len of the old encoding of index value.
MaxOldEncodeValueLen = 9
)
// TableSplitKeyLen is the length of key 't{table_id}' which is used for table split.
const TableSplitKeyLen = 1 + idLen
// TablePrefix returns table's prefix 't'.
func TablePrefix() []byte {
return tablePrefix
}
// EncodeRowKey encodes the table id and record handle into a kv.Key
func EncodeRowKey(tableID int64, encodedHandle []byte) kv.Key {
buf := make([]byte, 0, RecordRowKeyLen)
buf = appendTableRecordPrefix(buf, tableID)
buf = append(buf, encodedHandle...)
return buf
}
// EncodeRowKeyWithHandle encodes the table id, row handle into a kv.Key
func EncodeRowKeyWithHandle(tableID int64, handle int64) kv.Key {
buf := make([]byte, 0, RecordRowKeyLen)
buf = appendTableRecordPrefix(buf, tableID)
buf = codec.EncodeInt(buf, handle)
return buf
}
// CutRowKeyPrefix cuts the row key prefix.
func CutRowKeyPrefix(key kv.Key) []byte {
return key[prefixLen:]
}
// EncodeRecordKey encodes the recordPrefix, row handle into a kv.Key.
func EncodeRecordKey(recordPrefix kv.Key, h int64) kv.Key {
buf := make([]byte, 0, len(recordPrefix)+idLen)
buf = append(buf, recordPrefix...)
buf = codec.EncodeInt(buf, h)
return buf
}
func hasTablePrefix(key kv.Key) bool {
return key[0] == tablePrefix[0]
}
func hasRecordPrefixSep(key kv.Key) bool {
return key[0] == recordPrefixSep[0] && key[1] == recordPrefixSep[1]
}
// DecodeRecordKey decodes the key and gets the tableID, handle.
func DecodeRecordKey(key kv.Key) (tableID int64, handle int64, err error) {
if len(key) <= prefixLen {
return 0, 0, errInvalidRecordKey.GenWithStack("invalid record key - %q", key)
}
k := key
if !hasTablePrefix(key) {
return 0, 0, errInvalidRecordKey.GenWithStack("invalid record key - %q", k)
}
key = key[tablePrefixLength:]
key, tableID, err = codec.DecodeInt(key)
if err != nil {
return 0, 0, errors.Trace(err)
}
if !hasRecordPrefixSep(key) {
return 0, 0, errInvalidRecordKey.GenWithStack("invalid record key - %q", k)
}
key = key[recordPrefixSepLength:]
key, handle, err = codec.DecodeInt(key)
if err != nil {
return 0, 0, errors.Trace(err)
}
return
}
// DecodeIndexKey decodes the key and gets the tableID, indexID, indexValues.
func DecodeIndexKey(key kv.Key) (tableID int64, indexID int64, indexValues []string, err error) {
k := key
tableID, indexID, key, err = DecodeIndexKeyPrefix(key)
if err != nil {
return 0, 0, nil, errors.Trace(err)
}
for len(key) > 0 {
// FIXME: Without the schema information, we can only decode the raw kind of
// the column. For instance, MysqlTime is internally saved as uint64.
remain, d, e := codec.DecodeOne(key)
if e != nil {
return 0, 0, nil, errInvalidIndexKey.GenWithStack("invalid index key - %q %v", k, e)
}
str, e1 := d.ToString()
if e1 != nil {
return 0, 0, nil, errInvalidIndexKey.GenWithStack("invalid index key - %q %v", k, e1)
}
indexValues = append(indexValues, str)
key = remain
}
return
}
// DecodeMetaKey decodes the key and get the meta key and meta field.
func DecodeMetaKey(ek kv.Key) (key []byte, field []byte, err error) {
var tp uint64
if !bytes.HasPrefix(ek, metaPrefix) {
return nil, nil, errors.New("invalid encoded hash data key prefix")
}
ek = ek[metaPrefixLength:]
ek, key, err = codec.DecodeBytes(ek, nil)
if err != nil {
return nil, nil, errors.Trace(err)
}
ek, tp, err = codec.DecodeUint(ek)
if err != nil {
return nil, nil, errors.Trace(err)
} else if structure.TypeFlag(tp) != structure.HashData {
return nil, nil, errors.Errorf("invalid encoded hash data key flag %c", byte(tp))
}
_, field, err = codec.DecodeBytes(ek, nil)
return key, field, errors.Trace(err)
}
// DecodeIndexKeyPrefix decodes the key and gets the tableID, indexID, indexValues.
func DecodeIndexKeyPrefix(key kv.Key) (tableID int64, indexID int64, indexValues []byte, err error) {
k := key
tableID, indexID, isRecord, err := DecodeKeyHead(key)
if err != nil {
return 0, 0, nil, errors.Trace(err)
}
if isRecord {
return 0, 0, nil, errInvalidIndexKey.GenWithStack("invalid index key - %q", k)
}
indexValues = key[prefixLen+idLen:]
return tableID, indexID, indexValues, nil
}
// DecodeKeyHead decodes the key's head and gets the tableID, indexID. isRecordKey is true when is a record key.
func DecodeKeyHead(key kv.Key) (tableID int64, indexID int64, isRecordKey bool, err error) {
isRecordKey = false
k := key
if !key.HasPrefix(tablePrefix) {
err = errInvalidKey.GenWithStack("invalid key - %q", k)
return
}
key = key[len(tablePrefix):]
key, tableID, err = codec.DecodeInt(key)
if err != nil {
err = errors.Trace(err)
return
}
if key.HasPrefix(recordPrefixSep) {
isRecordKey = true
return
}
if !key.HasPrefix(indexPrefixSep) {
err = errInvalidKey.GenWithStack("invalid key - %q", k)
return
}
key = key[len(indexPrefixSep):]
key, indexID, err = codec.DecodeInt(key)
if err != nil {
err = errors.Trace(err)
return
}
return
}
// DecodeTableID decodes the table ID of the key, if the key is not table key, returns 0.
func DecodeTableID(key kv.Key) int64 {
if !key.HasPrefix(tablePrefix) {
return 0
}
key = key[len(tablePrefix):]
_, tableID, err := codec.DecodeInt(key)
// TODO: return error.
terror.Log(errors.Trace(err))
return tableID
}
// DecodeRowKey decodes the key and gets the handle.
func DecodeRowKey(key kv.Key) (int64, error) {
if len(key) != RecordRowKeyLen || !hasTablePrefix(key) || !hasRecordPrefixSep(key[prefixLen-2:]) {
return 0, errInvalidKey.GenWithStack("invalid key - %q", key)
}
u := binary.BigEndian.Uint64(key[prefixLen:])
return codec.DecodeCmpUintToInt(u), nil
}
// EncodeValue encodes a go value to bytes.
func EncodeValue(sc *stmtctx.StatementContext, b []byte, raw types.Datum) ([]byte, error) {
var v types.Datum
err := flatten(sc, raw, &v)
if err != nil {
return nil, err
}
return codec.EncodeValue(sc, b, v)
}
// EncodeRow encode row data and column ids into a slice of byte.
// valBuf and values pass by caller, for reducing EncodeRow allocates temporary bufs. If you pass valBuf and values as nil,
// EncodeRow will allocate it.
func EncodeRow(sc *stmtctx.StatementContext, row []types.Datum, colIDs []int64, valBuf []byte, values []types.Datum, e *rowcodec.Encoder) ([]byte, error) {
if len(row) != len(colIDs) {
return nil, errors.Errorf("EncodeRow error: data and columnID count not match %d vs %d", len(row), len(colIDs))
}
if e.Enable {
return e.Encode(sc, colIDs, row, valBuf)
}
return EncodeOldRow(sc, row, colIDs, valBuf, values)
}
// EncodeOldRow encode row data and column ids into a slice of byte.
// Row layout: colID1, value1, colID2, value2, .....
// valBuf and values pass by caller, for reducing EncodeOldRow allocates temporary bufs. If you pass valBuf and values as nil,
// EncodeOldRow will allocate it.
func EncodeOldRow(sc *stmtctx.StatementContext, row []types.Datum, colIDs []int64, valBuf []byte, values []types.Datum) ([]byte, error) {
if len(row) != len(colIDs) {
return nil, errors.Errorf("EncodeRow error: data and columnID count not match %d vs %d", len(row), len(colIDs))
}
valBuf = valBuf[:0]
if values == nil {
values = make([]types.Datum, len(row)*2)
}
for i, c := range row {
id := colIDs[i]
values[2*i].SetInt64(id)
err := flatten(sc, c, &values[2*i+1])
if err != nil {
return valBuf, errors.Trace(err)
}
}
if len(values) == 0 {
// We could not set nil value into kv.
return append(valBuf, codec.NilFlag), nil
}
return codec.EncodeValue(sc, valBuf, values...)
}
func flatten(sc *stmtctx.StatementContext, data types.Datum, ret *types.Datum) error {
switch data.Kind() {
case types.KindMysqlTime:
// for mysql datetime, timestamp and date type
t := data.GetMysqlTime()
if t.Type() == mysql.TypeTimestamp && sc.TimeZone != time.UTC {
err := t.ConvertTimeZone(sc.TimeZone, time.UTC)
if err != nil {
return errors.Trace(err)
}
}
v, err := t.ToPackedUint()
ret.SetUint64(v)
return errors.Trace(err)
case types.KindMysqlDuration:
// for mysql time type
ret.SetInt64(int64(data.GetMysqlDuration().Duration))
return nil
case types.KindMysqlEnum:
ret.SetUint64(data.GetMysqlEnum().Value)
return nil
case types.KindMysqlSet:
ret.SetUint64(data.GetMysqlSet().Value)
return nil
case types.KindBinaryLiteral, types.KindMysqlBit:
// We don't need to handle errors here since the literal is ensured to be able to store in uint64 in convertToMysqlBit.
val, err := data.GetBinaryLiteral().ToInt(sc)
if err != nil {
return errors.Trace(err)
}
ret.SetUint64(val)
return nil
default:
*ret = data
return nil
}
}
// DecodeColumnValue decodes data to a Datum according to the column info.
func DecodeColumnValue(data []byte, ft *types.FieldType, loc *time.Location) (types.Datum, error) {
_, d, err := codec.DecodeOne(data)
if err != nil {
return types.Datum{}, errors.Trace(err)
}
colDatum, err := unflatten(d, ft, loc)
if err != nil {
return types.Datum{}, errors.Trace(err)
}
return colDatum, nil
}
// DecodeRowWithMapNew decode a row to datum map.
func DecodeRowWithMapNew(b []byte, cols map[int64]*types.FieldType, loc *time.Location, row map[int64]types.Datum) (map[int64]types.Datum, error) {
if row == nil {
row = make(map[int64]types.Datum, len(cols))
}
if b == nil {
return row, nil
}
if len(b) == 1 && b[0] == codec.NilFlag {
return row, nil
}
reqCols := make([]rowcodec.ColInfo, len(cols))
var idx int
for id, tp := range cols {
reqCols[idx] = rowcodec.ColInfo{
ID: id,
Tp: int32(tp.Tp),
Flag: int32(tp.Flag),
Flen: tp.Flen,
Decimal: tp.Decimal,
Elems: tp.Elems,
Collate: tp.Collate,
}
idx++
}
// for decodeToMap:
// - no need handle
// - no need get default value
rd := rowcodec.NewDatumMapDecoder(reqCols, -1, loc)
return rd.DecodeToDatumMap(b, -1, row)
}
// DecodeRowWithMap decodes a byte slice into datums with a existing row map.
// Row layout: colID1, value1, colID2, value2, .....
func DecodeRowWithMap(b []byte, cols map[int64]*types.FieldType, loc *time.Location, row map[int64]types.Datum) (map[int64]types.Datum, error) {
if row == nil {
row = make(map[int64]types.Datum, len(cols))
}
if b == nil {
return row, nil
}
if len(b) == 1 && b[0] == codec.NilFlag {
return row, nil
}
cnt := 0
var (
data []byte
err error
)
for len(b) > 0 {
// Get col id.
data, b, err = codec.CutOne(b)
if err != nil {
return nil, errors.Trace(err)
}
_, cid, err := codec.DecodeOne(data)
if err != nil {
return nil, errors.Trace(err)
}
// Get col value.
data, b, err = codec.CutOne(b)
if err != nil {
return nil, errors.Trace(err)
}
id := cid.GetInt64()
ft, ok := cols[id]
if ok {
_, v, err := codec.DecodeOne(data)
if err != nil {
return nil, errors.Trace(err)
}
v, err = unflatten(v, ft, loc)
if err != nil {
return nil, errors.Trace(err)
}
row[id] = v
cnt++
if cnt == len(cols) {
// Get enough data.
break
}
}
}
return row, nil
}
// DecodeRow decodes a byte slice into datums.
// Row layout: colID1, value1, colID2, value2, .....
func DecodeRow(b []byte, cols map[int64]*types.FieldType, loc *time.Location) (map[int64]types.Datum, error) {
if !rowcodec.IsNewFormat(b) {
return DecodeRowWithMap(b, cols, loc, nil)
}
return DecodeRowWithMapNew(b, cols, loc, nil)
}
// CutRowNew cuts encoded row into byte slices and return columns' byte slice.
// Row layout: colID1, value1, colID2, value2, .....
func CutRowNew(data []byte, colIDs map[int64]int) ([][]byte, error) {
if data == nil {
return nil, nil
}
if len(data) == 1 && data[0] == codec.NilFlag {
return nil, nil
}
var (
cnt int
b []byte
err error
cid int64
)
row := make([][]byte, len(colIDs))
for len(data) > 0 && cnt < len(colIDs) {
// Get col id.
data, cid, err = codec.CutColumnID(data)
if err != nil {
return nil, errors.Trace(err)
}
// Get col value.
b, data, err = codec.CutOne(data)
if err != nil {
return nil, errors.Trace(err)
}
offset, ok := colIDs[cid]
if ok {
row[offset] = b
cnt++
}
}
return row, nil
}
// UnflattenDatums converts raw datums to column datums.
func UnflattenDatums(datums []types.Datum, fts []*types.FieldType, loc *time.Location) ([]types.Datum, error) {
for i, datum := range datums {
ft := fts[i]
uDatum, err := unflatten(datum, ft, loc)
if err != nil {
return datums, errors.Trace(err)
}
datums[i] = uDatum
}
return datums, nil
}
// unflatten converts a raw datum to a column datum.
func unflatten(datum types.Datum, ft *types.FieldType, loc *time.Location) (types.Datum, error) {
if datum.IsNull() {
return datum, nil
}
switch ft.Tp {
case mysql.TypeFloat:
datum.SetFloat32(float32(datum.GetFloat64()))
return datum, nil
case mysql.TypeVarchar, mysql.TypeString, mysql.TypeVarString:
datum.SetString(datum.GetString(), ft.Collate)
case mysql.TypeTiny, mysql.TypeShort, mysql.TypeYear, mysql.TypeInt24,
mysql.TypeLong, mysql.TypeLonglong, mysql.TypeDouble, mysql.TypeTinyBlob,
mysql.TypeMediumBlob, mysql.TypeBlob, mysql.TypeLongBlob:
return datum, nil
case mysql.TypeDate, mysql.TypeDatetime, mysql.TypeTimestamp:
t := types.NewTime(types.ZeroCoreTime, ft.Tp, int8(ft.Decimal))
var err error
err = t.FromPackedUint(datum.GetUint64())
if err != nil {
return datum, errors.Trace(err)
}
if ft.Tp == mysql.TypeTimestamp && !t.IsZero() {
err = t.ConvertTimeZone(time.UTC, loc)
if err != nil {
return datum, errors.Trace(err)
}
}
datum.SetUint64(0)
datum.SetMysqlTime(t)
return datum, nil
case mysql.TypeDuration: //duration should read fsp from column meta data
dur := types.Duration{Duration: time.Duration(datum.GetInt64()), Fsp: int8(ft.Decimal)}
datum.SetMysqlDuration(dur)
return datum, nil
case mysql.TypeEnum:
// ignore error deliberately, to read empty enum value.
enum, err := types.ParseEnumValue(ft.Elems, datum.GetUint64())
if err != nil {
enum = types.Enum{}
}
datum.SetMysqlEnum(enum, ft.Collate)
return datum, nil
case mysql.TypeSet:
set, err := types.ParseSetValue(ft.Elems, datum.GetUint64())
if err != nil {
return datum, errors.Trace(err)
}
datum.SetMysqlSet(set, ft.Collate)
return datum, nil
case mysql.TypeBit:
val := datum.GetUint64()
byteSize := (ft.Flen + 7) >> 3
datum.SetUint64(0)
datum.SetMysqlBit(types.NewBinaryLiteralFromUint(val, byteSize))
}
return datum, nil
}
// EncodeIndexSeekKey encodes an index value to kv.Key.
func EncodeIndexSeekKey(tableID int64, idxID int64, encodedValue []byte) kv.Key {
key := make([]byte, 0, prefixLen+len(encodedValue))
key = appendTableIndexPrefix(key, tableID)
key = codec.EncodeInt(key, idxID)
key = append(key, encodedValue...)
return key
}
// CutIndexKey cuts encoded index key into colIDs to bytes slices map.
// The returned value b is the remaining bytes of the key which would be empty if it is unique index or handle data
// if it is non-unique index.
func CutIndexKey(key kv.Key, colIDs []int64) (values map[int64][]byte, b []byte, err error) {
b = key[prefixLen+idLen:]
values = make(map[int64][]byte, len(colIDs))
for _, id := range colIDs {
var val []byte
val, b, err = codec.CutOne(b)
if err != nil {
return nil, nil, errors.Trace(err)
}
values[id] = val
}
return
}
// CutIndexPrefix cuts the index prefix.
func CutIndexPrefix(key kv.Key) []byte {
return key[prefixLen+idLen:]
}
// CutIndexKeyNew cuts encoded index key into colIDs to bytes slices.
// The returned value b is the remaining bytes of the key which would be empty if it is unique index or handle data
// if it is non-unique index.
func CutIndexKeyNew(key kv.Key, length int) (values [][]byte, b []byte, err error) {
b = key[prefixLen+idLen:]
values = make([][]byte, 0, length)
for i := 0; i < length; i++ {
var val []byte
val, b, err = codec.CutOne(b)
if err != nil {
return nil, nil, errors.Trace(err)
}
values = append(values, val)
}
return
}
// HandleStatus is the handle status in index.
type HandleStatus int
const (
// HandleNotExists means no need to decode handle value when DecodeIndexKV.
HandleNotExists HandleStatus = iota
// HandleIsSigned means decode handle value as int64 when DecodeIndexKV.
HandleIsSigned
// HandleIsUnsigned means decode handle value as uint64 when DecodeIndexKV.
HandleIsUnsigned
)
func handleExists(hdStatus HandleStatus) bool {
return hdStatus != HandleNotExists
}
// reEncodeHandleByStatus first decode the value into a int or uint decided by the hdStatus, then encode it so that it can
// be properly decoded.
func reEncodeHandleByStatus(value []byte, hdStatus HandleStatus) ([]byte, error) {
handle, err := DecodeIndexValueAsHandle(value)
if err != nil {
return nil, errors.Trace(err)
}
var handleDatum types.Datum
if hdStatus == HandleIsUnsigned {
handleDatum = types.NewUintDatum(uint64(handle))
} else {
handleDatum = types.NewIntDatum(handle)
}
handleBytes := make([]byte, 0, 8)
handleBytes, err = codec.EncodeValue(nil, handleBytes, handleDatum)
if err != nil {
return nil, errors.Trace(err)
}
return handleBytes, nil
}
func decodeIndexKvNewCollation(key, value []byte, colsLen int, hdStatus HandleStatus, columns []rowcodec.ColInfo) ([][]byte, error) {
colIDs := make(map[int64]int, len(columns))
for i, col := range columns {
colIDs[col.ID] = i
}
// We don't need to decode handle here, and colIDs >= 0 always.
rd := rowcodec.NewByteDecoder(columns, -1, nil, nil)
vLen := len(value)
tailLen := int(value[0])
resultValues, err := rd.DecodeToBytesNoHandle(colIDs, value[1:vLen-tailLen])
if err != nil {
return nil, errors.Trace(err)
}
if tailLen < 8 {
// In non-unique index.
if handleExists(hdStatus) {
resultValues = append(resultValues, key[len(key)-9:])
}
} else {
// In unique index.
if handleExists(hdStatus) {
handleBytes, err := reEncodeHandleByStatus(value[vLen-tailLen:], hdStatus)
if err != nil {
return nil, errors.Trace(err)
}
resultValues = append(resultValues, handleBytes)
}
}
return resultValues, nil
}
func decodeIndexKvOldCollation(key, value []byte, colsLen int, hdStatus HandleStatus) ([][]byte, error) {
resultValues, b, err := CutIndexKeyNew(key, colsLen)
if err != nil {
return nil, errors.Trace(err)
}
if len(b) > 0 {
// non-unique index
if handleExists(hdStatus) {
resultValues = append(resultValues, b)
}
} else if handleExists(hdStatus) {
// unique index
handleBytes, err := reEncodeHandleByStatus(value, hdStatus)
if err != nil {
return nil, errors.Trace(err)
}
resultValues = append(resultValues, handleBytes)
}
return resultValues, nil
}
// DecodeIndexKV uses to decode index key values.
func DecodeIndexKV(key, value []byte, colsLen int, hdStatus HandleStatus, columns []rowcodec.ColInfo) ([][]byte, error) {
if len(value) > MaxOldEncodeValueLen {
return decodeIndexKvNewCollation(key, value, colsLen, hdStatus, columns)
}
return decodeIndexKvOldCollation(key, value, colsLen, hdStatus)
}
// DecodeIndexHandle uses to decode the handle from index key/value.
func DecodeIndexHandle(key, value []byte, colsLen int, pkTp *types.FieldType) (int64, error) {
_, b, err := CutIndexKeyNew(key, colsLen)
if err != nil {
return 0, errors.Trace(err)
}
if len(b) > 0 {
d, err := DecodeColumnValue(b, pkTp, nil)
if err != nil {
return 0, errors.Trace(err)
}
return d.GetInt64(), nil
} else if len(value) >= 8 {
return decodeHandleInIndexValue(value)
}
// Should never execute to here.
return 0, errors.Errorf("no handle in index key: %v, value: %v", key, value)
}
func decodeHandleInIndexValue(value []byte) (int64, error) {
if len(value) > MaxOldEncodeValueLen {
tailLen := value[0]
if tailLen >= 8 {
return DecodeIndexValueAsHandle(value[len(value)-int(tailLen):])
}
// Should never executed to here, since the handle is encoded in IndexKey.
return 0, errors.Errorf("no handle in index value: %v", value)
}
return DecodeIndexValueAsHandle(value)
}
// DecodeIndexValueAsHandle uses to decode index value as handle id.
func DecodeIndexValueAsHandle(data []byte) (int64, error) {
var h int64
buf := bytes.NewBuffer(data)
err := binary.Read(buf, binary.BigEndian, &h)
return h, errors.Trace(err)
}
// EncodeTableIndexPrefix encodes index prefix with tableID and idxID.
func EncodeTableIndexPrefix(tableID, idxID int64) kv.Key {
key := make([]byte, 0, prefixLen)
key = appendTableIndexPrefix(key, tableID)
key = codec.EncodeInt(key, idxID)
return key
}
// EncodeTablePrefix encodes table prefix with table ID.
func EncodeTablePrefix(tableID int64) kv.Key {
var key kv.Key
key = append(key, tablePrefix...)
key = codec.EncodeInt(key, tableID)
return key
}
// appendTableRecordPrefix appends table record prefix "t[tableID]_r".
func appendTableRecordPrefix(buf []byte, tableID int64) []byte {
buf = append(buf, tablePrefix...)
buf = codec.EncodeInt(buf, tableID)
buf = append(buf, recordPrefixSep...)
return buf
}
// appendTableIndexPrefix appends table index prefix "t[tableID]_i".
func appendTableIndexPrefix(buf []byte, tableID int64) []byte {
buf = append(buf, tablePrefix...)
buf = codec.EncodeInt(buf, tableID)
buf = append(buf, indexPrefixSep...)
return buf
}
// ReplaceRecordKeyTableID replace the tableID in the recordKey buf.
func ReplaceRecordKeyTableID(buf []byte, tableID int64) []byte {
if len(buf) < len(tablePrefix)+8 {
return buf
}
u := codec.EncodeIntToCmpUint(tableID)
binary.BigEndian.PutUint64(buf[len(tablePrefix):], u)
return buf
}
// GenTableRecordPrefix composes record prefix with tableID: "t[tableID]_r".
func GenTableRecordPrefix(tableID int64) kv.Key {
buf := make([]byte, 0, len(tablePrefix)+8+len(recordPrefixSep))
return appendTableRecordPrefix(buf, tableID)
}
// GenTableIndexPrefix composes index prefix with tableID: "t[tableID]_i".
func GenTableIndexPrefix(tableID int64) kv.Key {
buf := make([]byte, 0, len(tablePrefix)+8+len(indexPrefixSep))
return appendTableIndexPrefix(buf, tableID)
}
// IsIndexKey is used to check whether the key is an index key.
func IsIndexKey(k []byte) bool {
return len(k) > 11 && k[0] == 't' && k[10] == 'i'
}
// IsUntouchedIndexKValue uses to check whether the key is index key, and the value is untouched,
// since the untouched index key/value is no need to commit.
func IsUntouchedIndexKValue(k, v []byte) bool {
if !IsIndexKey(k) {
return false
}
vLen := len(v)
if vLen <= MaxOldEncodeValueLen {
return (vLen == 1 || vLen == 9) && v[vLen-1] == kv.UnCommitIndexKVFlag
}
// New index value format
tailLen := int(v[0])
if tailLen < 8 {
// Non-unique index.
return tailLen >= 1 && v[vLen-1] == kv.UnCommitIndexKVFlag
}
// Unique index
return tailLen == 9
}
// GenTablePrefix composes table record and index prefix: "t[tableID]".
func GenTablePrefix(tableID int64) kv.Key {
buf := make([]byte, 0, len(tablePrefix)+8)
buf = append(buf, tablePrefix...)
buf = codec.EncodeInt(buf, tableID)
return buf
}
// TruncateToRowKeyLen truncates the key to row key length if the key is longer than row key.
func TruncateToRowKeyLen(key kv.Key) kv.Key {
if len(key) > RecordRowKeyLen {
return key[:RecordRowKeyLen]
}
return key
}
// GetTableHandleKeyRange returns table handle's key range with tableID.
func GetTableHandleKeyRange(tableID int64) (startKey, endKey []byte) {
startKey = EncodeRowKeyWithHandle(tableID, math.MinInt64)
endKey = EncodeRowKeyWithHandle(tableID, math.MaxInt64)
return
}
// GetTableIndexKeyRange returns table index's key range with tableID and indexID.
func GetTableIndexKeyRange(tableID, indexID int64) (startKey, endKey []byte) {
startKey = EncodeIndexSeekKey(tableID, indexID, nil)
endKey = EncodeIndexSeekKey(tableID, indexID, []byte{255})
return
}
// GetIndexKeyBuf reuse or allocate buffer.
func GetIndexKeyBuf(buf []byte, defaultCap int) []byte {
if buf != nil {
return buf[:0]
}
return make([]byte, 0, defaultCap)
}
// GenIndexKey generates index key using input physical table id.
func GenIndexKey(sc *stmtctx.StatementContext, tblInfo *model.TableInfo, idxInfo *model.IndexInfo,
phyTblID int64, indexedValues []types.Datum, h int64, buf []byte) (key []byte, distinct bool, err error) {
if idxInfo.Unique {
// See https://dev.mysql.com/doc/refman/5.7/en/create-index.html
// A UNIQUE index creates a constraint such that all values in the index must be distinct.
// An error occurs if you try to add a new row with a key value that matches an existing row.
// For all engines, a UNIQUE index permits multiple NULL values for columns that can contain NULL.
distinct = true
for _, cv := range indexedValues {
if cv.IsNull() {
distinct = false
break
}
}
}
// For string columns, indexes can be created using only the leading part of column values,
// using col_name(length) syntax to specify an index prefix length.
indexedValues = TruncateIndexValuesIfNeeded(tblInfo, idxInfo, indexedValues)
key = GetIndexKeyBuf(buf, RecordRowKeyLen+len(indexedValues)*9+9)
key = appendTableIndexPrefix(key, phyTblID)
key = codec.EncodeInt(key, idxInfo.ID)
key, err = codec.EncodeKey(sc, key, indexedValues...)
if err != nil {
return nil, false, err
}
if !distinct {
key, err = codec.EncodeKey(sc, key, types.NewDatum(h))
if err != nil {
return nil, false, err
}
}
return
}
// GenIndexValue creates encoded index value and returns the result.
func GenIndexValue(sc *stmtctx.StatementContext, tblInfo *model.TableInfo, idxInfo *model.IndexInfo,
containNonBinaryString bool, distinct bool, untouched bool, indexedValues []types.Datum, h int64) ([]byte, error) {
var idxVal []byte
if collate.NewCollationEnabled() && containNonBinaryString {
colIds := make([]int64, len(idxInfo.Columns))
for i, col := range idxInfo.Columns {
colIds[i] = tblInfo.Columns[col.Offset].ID
}
rd := rowcodec.Encoder{Enable: true}
rowRestoredValue, err := rd.Encode(sc, colIds, indexedValues, nil)
if err != nil {
return nil, err
}
idxVal = make([]byte, 1+len(rowRestoredValue))
copy(idxVal[1:], rowRestoredValue)
tailLen := 0
if distinct {
// The len of the idxVal is always >= 10 since len (restoredValue) > 0.
tailLen += 8
idxVal = append(idxVal, EncodeHandle(h)...)
} else if len(idxVal) < 10 {
// Padding the len to 10
paddingLen := 10 - len(idxVal)
tailLen += paddingLen
idxVal = append(idxVal, bytes.Repeat([]byte{0x0}, paddingLen)...)
}
if untouched {
// If index is untouched and fetch here means the key is exists in TiKV, but not in txn mem-buffer,
// then should also write the untouched index key/value to mem-buffer to make sure the data
// is consistent with the index in txn mem-buffer.
tailLen += 1
idxVal = append(idxVal, kv.UnCommitIndexKVFlag)
}
idxVal[0] = byte(tailLen)
} else {
idxVal = make([]byte, 0)
if distinct {
idxVal = EncodeHandle(h)
}
if untouched {
// If index is untouched and fetch here means the key is exists in TiKV, but not in txn mem-buffer,
// then should also write the untouched index key/value to mem-buffer to make sure the data
// is consistent with the index in txn mem-buffer.
idxVal = append(idxVal, kv.UnCommitIndexKVFlag)
}
if len(idxVal) == 0 {
idxVal = []byte{'0'}
}
}
return idxVal, nil
}
// TruncateIndexValuesIfNeeded truncates the index values created using only the leading part of column values.
func TruncateIndexValuesIfNeeded(tblInfo *model.TableInfo, idxInfo *model.IndexInfo, indexedValues []types.Datum) []types.Datum {
for i := 0; i < len(indexedValues); i++ {
v := &indexedValues[i]
if v.Kind() == types.KindString || v.Kind() == types.KindBytes {
ic := idxInfo.Columns[i]
colCharset := tblInfo.Columns[ic.Offset].Charset
colValue := v.GetBytes()
isUTF8Charset := colCharset == charset.CharsetUTF8 || colCharset == charset.CharsetUTF8MB4
origKind := v.Kind()
if isUTF8Charset {
if ic.Length != types.UnspecifiedLength && utf8.RuneCount(colValue) > ic.Length {
rs := bytes.Runes(colValue)
truncateStr := string(rs[:ic.Length])
// truncate value and limit its length
v.SetString(truncateStr, tblInfo.Columns[ic.Offset].Collate)
if origKind == types.KindBytes {
v.SetBytes(v.GetBytes())
}
}
} else if ic.Length != types.UnspecifiedLength && len(colValue) > ic.Length {
// truncate value and limit its length
v.SetBytes(colValue[:ic.Length])
if origKind == types.KindString {
v.SetString(v.GetString(), tblInfo.Columns[ic.Offset].Collate)
}
}
}
}
return indexedValues
}
// EncodeHandle encodes handle in data.
func EncodeHandle(h int64) []byte {
var data [8]byte
binary.BigEndian.PutUint64(data[:], uint64(h))
return data[:]
}
// DecodeHandle decodes handle in data.
func DecodeHandle(data []byte) (int64, error) {
dLen := len(data)
if dLen <= MaxOldEncodeValueLen {
return int64(binary.BigEndian.Uint64(data)), nil
}
return int64(binary.BigEndian.Uint64(data[dLen-int(data[0]):])), nil
}