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column.go
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// Copyright 2015 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 ddl
import (
"bytes"
"context"
"fmt"
"math/bits"
"strings"
"sync/atomic"
"time"
"github.com/pingcap/errors"
"github.com/pingcap/failpoint"
"github.com/pingcap/tidb/config"
ddlutil "github.com/pingcap/tidb/ddl/util"
"github.com/pingcap/tidb/expression"
"github.com/pingcap/tidb/infoschema"
"github.com/pingcap/tidb/kv"
"github.com/pingcap/tidb/meta"
"github.com/pingcap/tidb/meta/autoid"
"github.com/pingcap/tidb/metrics"
"github.com/pingcap/tidb/parser/ast"
"github.com/pingcap/tidb/parser/model"
"github.com/pingcap/tidb/parser/mysql"
"github.com/pingcap/tidb/parser/terror"
"github.com/pingcap/tidb/sessionctx"
"github.com/pingcap/tidb/sessionctx/stmtctx"
"github.com/pingcap/tidb/table"
"github.com/pingcap/tidb/tablecodec"
"github.com/pingcap/tidb/types"
"github.com/pingcap/tidb/util"
"github.com/pingcap/tidb/util/dbterror"
"github.com/pingcap/tidb/util/logutil"
decoder "github.com/pingcap/tidb/util/rowDecoder"
"github.com/pingcap/tidb/util/sqlexec"
"github.com/prometheus/client_golang/prometheus"
"go.uber.org/zap"
)
// InitAndAddColumnToTable initializes the ColumnInfo in-place and adds it to the table.
func InitAndAddColumnToTable(tblInfo *model.TableInfo, colInfo *model.ColumnInfo) *model.ColumnInfo {
cols := tblInfo.Columns
colInfo.ID = AllocateColumnID(tblInfo)
colInfo.State = model.StateNone
// To support add column asynchronous, we should mark its offset as the last column.
// So that we can use origin column offset to get value from row.
colInfo.Offset = len(cols)
// Append the column info to the end of the tblInfo.Columns.
// It will reorder to the right offset in "Columns" when it state change to public.
tblInfo.Columns = append(cols, colInfo)
return colInfo
}
func checkAddColumn(t *meta.Meta, job *model.Job) (*model.TableInfo, *model.ColumnInfo, *model.ColumnInfo,
*ast.ColumnPosition, bool /* ifNotExists */, error) {
schemaID := job.SchemaID
tblInfo, err := GetTableInfoAndCancelFaultJob(t, job, schemaID)
if err != nil {
return nil, nil, nil, nil, false, errors.Trace(err)
}
col := &model.ColumnInfo{}
pos := &ast.ColumnPosition{}
offset := 0
ifNotExists := false
err = job.DecodeArgs(col, pos, &offset, &ifNotExists)
if err != nil {
job.State = model.JobStateCancelled
return nil, nil, nil, nil, false, errors.Trace(err)
}
columnInfo := model.FindColumnInfo(tblInfo.Columns, col.Name.L)
if columnInfo != nil {
if columnInfo.State == model.StatePublic {
// We already have a column with the same column name.
job.State = model.JobStateCancelled
return nil, nil, nil, nil, ifNotExists, infoschema.ErrColumnExists.GenWithStackByArgs(col.Name)
}
}
err = CheckAfterPositionExists(tblInfo, pos)
if err != nil {
job.State = model.JobStateCancelled
return nil, nil, nil, nil, false, infoschema.ErrColumnExists.GenWithStackByArgs(col.Name)
}
return tblInfo, columnInfo, col, pos, false, nil
}
func onAddColumn(d *ddlCtx, t *meta.Meta, job *model.Job) (ver int64, err error) {
// Handle the rolling back job.
if job.IsRollingback() {
ver, err = onDropColumn(d, t, job)
if err != nil {
return ver, errors.Trace(err)
}
return ver, nil
}
failpoint.Inject("errorBeforeDecodeArgs", func(val failpoint.Value) {
//nolint:forcetypeassert
if val.(bool) {
failpoint.Return(ver, errors.New("occur an error before decode args"))
}
})
tblInfo, columnInfo, colFromArgs, pos, ifNotExists, err := checkAddColumn(t, job)
if err != nil {
if ifNotExists && infoschema.ErrColumnExists.Equal(err) {
job.Warning = toTError(err)
job.State = model.JobStateDone
return ver, nil
}
return ver, errors.Trace(err)
}
if columnInfo == nil {
columnInfo = InitAndAddColumnToTable(tblInfo, colFromArgs)
logutil.BgLogger().Info("[ddl] run add column job", zap.String("job", job.String()), zap.Reflect("columnInfo", *columnInfo))
if err = checkAddColumnTooManyColumns(len(tblInfo.Columns)); err != nil {
job.State = model.JobStateCancelled
return ver, errors.Trace(err)
}
}
originalState := columnInfo.State
switch columnInfo.State {
case model.StateNone:
// none -> delete only
columnInfo.State = model.StateDeleteOnly
ver, err = updateVersionAndTableInfoWithCheck(d, t, job, tblInfo, originalState != columnInfo.State)
if err != nil {
return ver, errors.Trace(err)
}
job.SchemaState = model.StateDeleteOnly
case model.StateDeleteOnly:
// delete only -> write only
columnInfo.State = model.StateWriteOnly
ver, err = updateVersionAndTableInfo(d, t, job, tblInfo, originalState != columnInfo.State)
if err != nil {
return ver, errors.Trace(err)
}
// Update the job state when all affairs done.
job.SchemaState = model.StateWriteOnly
case model.StateWriteOnly:
// write only -> reorganization
columnInfo.State = model.StateWriteReorganization
ver, err = updateVersionAndTableInfo(d, t, job, tblInfo, originalState != columnInfo.State)
if err != nil {
return ver, errors.Trace(err)
}
// Update the job state when all affairs done.
job.SchemaState = model.StateWriteReorganization
job.MarkNonRevertible()
case model.StateWriteReorganization:
// reorganization -> public
// Adjust table column offset.
offset, err := LocateOffsetToMove(columnInfo.Offset, pos, tblInfo)
if err != nil {
return ver, errors.Trace(err)
}
tblInfo.MoveColumnInfo(columnInfo.Offset, offset)
columnInfo.State = model.StatePublic
ver, err = updateVersionAndTableInfo(d, t, job, tblInfo, originalState != columnInfo.State)
if err != nil {
return ver, errors.Trace(err)
}
// Finish this job.
job.FinishTableJob(model.JobStateDone, model.StatePublic, ver, tblInfo)
asyncNotifyEvent(d, &ddlutil.Event{Tp: model.ActionAddColumn, TableInfo: tblInfo, ColumnInfos: []*model.ColumnInfo{columnInfo}})
default:
err = dbterror.ErrInvalidDDLState.GenWithStackByArgs("column", columnInfo.State)
}
return ver, errors.Trace(err)
}
// CheckAfterPositionExists makes sure the column specified in AFTER clause is exists.
// For example, ALTER TABLE t ADD COLUMN c3 INT AFTER c1.
func CheckAfterPositionExists(tblInfo *model.TableInfo, pos *ast.ColumnPosition) error {
if pos != nil && pos.Tp == ast.ColumnPositionAfter {
c := model.FindColumnInfo(tblInfo.Columns, pos.RelativeColumn.Name.L)
if c == nil {
return infoschema.ErrColumnNotExists.GenWithStackByArgs(pos.RelativeColumn, tblInfo.Name)
}
}
return nil
}
func setIndicesState(indexInfos []*model.IndexInfo, state model.SchemaState) {
for _, indexInfo := range indexInfos {
indexInfo.State = state
}
}
func checkDropColumnForStatePublic(colInfo *model.ColumnInfo) (err error) {
// When the dropping column has not-null flag and it hasn't the default value, we can backfill the column value like "add column".
// NOTE: If the state of StateWriteOnly can be rollbacked, we'd better reconsider the original default value.
// And we need consider the column without not-null flag.
if colInfo.GetOriginDefaultValue() == nil && mysql.HasNotNullFlag(colInfo.GetFlag()) {
// If the column is timestamp default current_timestamp, and DDL owner is new version TiDB that set column.Version to 1,
// then old TiDB update record in the column write only stage will uses the wrong default value of the dropping column.
// Because new version of the column default value is UTC time, but old version TiDB will think the default value is the time in system timezone.
// But currently will be ok, because we can't cancel the drop column job when the job is running,
// so the column will be dropped succeed and client will never see the wrong default value of the dropped column.
// More info about this problem, see PR#9115.
originDefVal, err := generateOriginDefaultValue(colInfo, nil)
if err != nil {
return err
}
return colInfo.SetOriginDefaultValue(originDefVal)
}
return nil
}
func onDropColumn(d *ddlCtx, t *meta.Meta, job *model.Job) (ver int64, _ error) {
tblInfo, colInfo, idxInfos, ifExists, err := checkDropColumn(t, job)
if err != nil {
if ifExists && dbterror.ErrCantDropFieldOrKey.Equal(err) {
// Convert the "not exists" error to a warning.
job.Warning = toTError(err)
job.State = model.JobStateDone
return ver, nil
}
return ver, errors.Trace(err)
}
if job.MultiSchemaInfo != nil && !job.IsRollingback() && job.MultiSchemaInfo.Revertible {
job.MarkNonRevertible()
job.SchemaState = colInfo.State
// Store the mark and enter the next DDL handling loop.
return updateVersionAndTableInfoWithCheck(d, t, job, tblInfo, false)
}
originalState := colInfo.State
switch colInfo.State {
case model.StatePublic:
// public -> write only
colInfo.State = model.StateWriteOnly
setIndicesState(idxInfos, model.StateWriteOnly)
tblInfo.MoveColumnInfo(colInfo.Offset, len(tblInfo.Columns)-1)
err = checkDropColumnForStatePublic(colInfo)
if err != nil {
return ver, errors.Trace(err)
}
ver, err = updateVersionAndTableInfoWithCheck(d, t, job, tblInfo, originalState != colInfo.State)
if err != nil {
return ver, errors.Trace(err)
}
case model.StateWriteOnly:
// write only -> delete only
colInfo.State = model.StateDeleteOnly
tblInfo.MoveColumnInfo(colInfo.Offset, len(tblInfo.Columns)-1)
if len(idxInfos) > 0 {
newIndices := make([]*model.IndexInfo, 0, len(tblInfo.Indices))
for _, idx := range tblInfo.Indices {
if !indexInfoContains(idx.ID, idxInfos) {
newIndices = append(newIndices, idx)
}
}
tblInfo.Indices = newIndices
}
ver, err = updateVersionAndTableInfo(d, t, job, tblInfo, originalState != colInfo.State)
if err != nil {
return ver, errors.Trace(err)
}
job.Args = append(job.Args, indexInfosToIDList(idxInfos))
case model.StateDeleteOnly:
// delete only -> reorganization
colInfo.State = model.StateDeleteReorganization
tblInfo.MoveColumnInfo(colInfo.Offset, len(tblInfo.Columns)-1)
ver, err = updateVersionAndTableInfo(d, t, job, tblInfo, originalState != colInfo.State)
if err != nil {
return ver, errors.Trace(err)
}
case model.StateDeleteReorganization:
// reorganization -> absent
// All reorganization jobs are done, drop this column.
tblInfo.MoveColumnInfo(colInfo.Offset, len(tblInfo.Columns)-1)
tblInfo.Columns = tblInfo.Columns[:len(tblInfo.Columns)-1]
colInfo.State = model.StateNone
ver, err = updateVersionAndTableInfo(d, t, job, tblInfo, originalState != colInfo.State)
if err != nil {
return ver, errors.Trace(err)
}
// Finish this job.
if job.IsRollingback() {
job.FinishTableJob(model.JobStateRollbackDone, model.StateNone, ver, tblInfo)
} else {
// We should set related index IDs for job
job.FinishTableJob(model.JobStateDone, model.StateNone, ver, tblInfo)
job.Args = append(job.Args, getPartitionIDs(tblInfo))
}
default:
return ver, errors.Trace(dbterror.ErrInvalidDDLJob.GenWithStackByArgs("table", tblInfo.State))
}
job.SchemaState = colInfo.State
return ver, errors.Trace(err)
}
func checkDropColumn(t *meta.Meta, job *model.Job) (*model.TableInfo, *model.ColumnInfo, []*model.IndexInfo, bool /* ifExists */, error) {
schemaID := job.SchemaID
tblInfo, err := GetTableInfoAndCancelFaultJob(t, job, schemaID)
if err != nil {
return nil, nil, nil, false, errors.Trace(err)
}
var colName model.CIStr
var ifExists bool
// indexIds is used to make sure we don't truncate args when decoding the rawArgs.
var indexIds []int64
err = job.DecodeArgs(&colName, &ifExists, &indexIds)
if err != nil {
job.State = model.JobStateCancelled
return nil, nil, nil, false, errors.Trace(err)
}
colInfo := model.FindColumnInfo(tblInfo.Columns, colName.L)
if colInfo == nil || colInfo.Hidden {
job.State = model.JobStateCancelled
return nil, nil, nil, ifExists, dbterror.ErrCantDropFieldOrKey.GenWithStack("column %s doesn't exist", colName)
}
if err = isDroppableColumn(tblInfo, colName); err != nil {
job.State = model.JobStateCancelled
return nil, nil, nil, false, errors.Trace(err)
}
idxInfos := listIndicesWithColumn(colName.L, tblInfo.Indices)
return tblInfo, colInfo, idxInfos, false, nil
}
func onSetDefaultValue(d *ddlCtx, t *meta.Meta, job *model.Job) (ver int64, _ error) {
newCol := &model.ColumnInfo{}
err := job.DecodeArgs(newCol)
if err != nil {
job.State = model.JobStateCancelled
return ver, errors.Trace(err)
}
return updateColumnDefaultValue(d, t, job, newCol, &newCol.Name)
}
func needChangeColumnData(oldCol, newCol *model.ColumnInfo) bool {
toUnsigned := mysql.HasUnsignedFlag(newCol.GetFlag())
originUnsigned := mysql.HasUnsignedFlag(oldCol.GetFlag())
needTruncationOrToggleSign := func() bool {
return (newCol.GetFlen() > 0 && newCol.GetFlen() < oldCol.GetFlen()) || (toUnsigned != originUnsigned)
}
// Ignore the potential max display length represented by integer's flen, use default flen instead.
defaultOldColFlen, _ := mysql.GetDefaultFieldLengthAndDecimal(oldCol.GetType())
defaultNewColFlen, _ := mysql.GetDefaultFieldLengthAndDecimal(newCol.GetType())
needTruncationOrToggleSignForInteger := func() bool {
return (defaultNewColFlen > 0 && defaultNewColFlen < defaultOldColFlen) || (toUnsigned != originUnsigned)
}
// Deal with the same type.
if oldCol.GetType() == newCol.GetType() {
switch oldCol.GetType() {
case mysql.TypeNewDecimal:
// Since type decimal will encode the precision, frac, negative(signed) and wordBuf into storage together, there is no short
// cut to eliminate data reorg change for column type change between decimal.
return oldCol.GetFlen() != newCol.GetFlen() || oldCol.GetDecimal() != newCol.GetDecimal() || toUnsigned != originUnsigned
case mysql.TypeEnum, mysql.TypeSet:
return isElemsChangedToModifyColumn(oldCol.GetElems(), newCol.GetElems())
case mysql.TypeTiny, mysql.TypeShort, mysql.TypeInt24, mysql.TypeLong, mysql.TypeLonglong:
return toUnsigned != originUnsigned
case mysql.TypeString:
// Due to the behavior of padding \x00 at binary type, always change column data when binary length changed
if types.IsBinaryStr(&oldCol.FieldType) {
return newCol.GetFlen() != oldCol.GetFlen()
}
}
return needTruncationOrToggleSign()
}
if convertBetweenCharAndVarchar(oldCol.GetType(), newCol.GetType()) {
return true
}
// Deal with the different type.
switch oldCol.GetType() {
case mysql.TypeVarchar, mysql.TypeString, mysql.TypeVarString, mysql.TypeBlob, mysql.TypeTinyBlob, mysql.TypeMediumBlob, mysql.TypeLongBlob:
switch newCol.GetType() {
case mysql.TypeVarchar, mysql.TypeString, mysql.TypeVarString, mysql.TypeBlob, mysql.TypeTinyBlob, mysql.TypeMediumBlob, mysql.TypeLongBlob:
return needTruncationOrToggleSign()
}
case mysql.TypeTiny, mysql.TypeShort, mysql.TypeInt24, mysql.TypeLong, mysql.TypeLonglong:
switch newCol.GetType() {
case mysql.TypeTiny, mysql.TypeShort, mysql.TypeInt24, mysql.TypeLong, mysql.TypeLonglong:
return needTruncationOrToggleSignForInteger()
}
// conversion between float and double needs reorganization, see issue #31372
}
return true
}
// TODO: it is used for plugins. so change plugin's using and remove it.
func convertBetweenCharAndVarchar(oldCol, newCol byte) bool {
return types.ConvertBetweenCharAndVarchar(oldCol, newCol)
}
func isElemsChangedToModifyColumn(oldElems, newElems []string) bool {
if len(newElems) < len(oldElems) {
return true
}
for index, oldElem := range oldElems {
newElem := newElems[index]
if oldElem != newElem {
return true
}
}
return false
}
type modifyingColInfo struct {
newCol *model.ColumnInfo
oldColName *model.CIStr
modifyColumnTp byte
updatedAutoRandomBits uint64
changingCol *model.ColumnInfo
changingIdxs []*model.IndexInfo
pos *ast.ColumnPosition
removedIdxs []int64
}
func getModifyColumnInfo(t *meta.Meta, job *model.Job) (*model.DBInfo, *model.TableInfo, *model.ColumnInfo, *modifyingColInfo, error) {
modifyInfo := &modifyingColInfo{pos: &ast.ColumnPosition{}}
err := job.DecodeArgs(&modifyInfo.newCol, &modifyInfo.oldColName, modifyInfo.pos, &modifyInfo.modifyColumnTp,
&modifyInfo.updatedAutoRandomBits, &modifyInfo.changingCol, &modifyInfo.changingIdxs, &modifyInfo.removedIdxs)
if err != nil {
job.State = model.JobStateCancelled
return nil, nil, nil, modifyInfo, errors.Trace(err)
}
dbInfo, err := checkSchemaExistAndCancelNotExistJob(t, job)
if err != nil {
return nil, nil, nil, modifyInfo, errors.Trace(err)
}
tblInfo, err := GetTableInfoAndCancelFaultJob(t, job, job.SchemaID)
if err != nil {
return nil, nil, nil, modifyInfo, errors.Trace(err)
}
oldCol := model.FindColumnInfo(tblInfo.Columns, modifyInfo.oldColName.L)
if oldCol == nil || oldCol.State != model.StatePublic {
job.State = model.JobStateCancelled
return nil, nil, nil, modifyInfo, errors.Trace(infoschema.ErrColumnNotExists.GenWithStackByArgs(*(modifyInfo.oldColName), tblInfo.Name))
}
return dbInfo, tblInfo, oldCol, modifyInfo, errors.Trace(err)
}
// GetOriginDefaultValueForModifyColumn gets the original default value for modifying column.
// Since column type change is implemented as adding a new column then substituting the old one.
// Case exists when update-where statement fetch a NULL for not-null column without any default data,
// it will errors.
// So we set original default value here to prevent this error. If the oldCol has the original default value, we use it.
// Otherwise we set the zero value as original default value.
// Besides, in insert & update records, we have already implement using the casted value of relative column to insert
// rather than the original default value.
func GetOriginDefaultValueForModifyColumn(sessCtx sessionctx.Context, changingCol, oldCol *model.ColumnInfo) (interface{}, error) {
var err error
originDefVal := oldCol.GetOriginDefaultValue()
if originDefVal != nil {
odv, err := table.CastValue(sessCtx, types.NewDatum(originDefVal), changingCol, false, false)
if err != nil {
logutil.BgLogger().Info("[ddl] cast origin default value failed", zap.Error(err))
}
if !odv.IsNull() {
if originDefVal, err = odv.ToString(); err != nil {
originDefVal = nil
logutil.BgLogger().Info("[ddl] convert default value to string failed", zap.Error(err))
}
}
}
if originDefVal == nil {
originDefVal, err = generateOriginDefaultValue(changingCol, nil)
if err != nil {
return nil, errors.Trace(err)
}
}
return originDefVal, nil
}
func (w *worker) onModifyColumn(d *ddlCtx, t *meta.Meta, job *model.Job) (ver int64, _ error) {
dbInfo, tblInfo, oldCol, modifyInfo, err := getModifyColumnInfo(t, job)
if err != nil {
return ver, err
}
if job.IsRollingback() {
// For those column-type-change jobs which don't reorg the data.
if !needChangeColumnData(oldCol, modifyInfo.newCol) {
return rollbackModifyColumnJob(d, t, tblInfo, job, modifyInfo.newCol, oldCol, modifyInfo.modifyColumnTp)
}
// For those column-type-change jobs which reorg the data.
return rollbackModifyColumnJobWithData(d, t, tblInfo, job, oldCol, modifyInfo)
}
// If we want to rename the column name, we need to check whether it already exists.
if modifyInfo.newCol.Name.L != modifyInfo.oldColName.L {
c := model.FindColumnInfo(tblInfo.Columns, modifyInfo.newCol.Name.L)
if c != nil {
job.State = model.JobStateCancelled
return ver, errors.Trace(infoschema.ErrColumnExists.GenWithStackByArgs(modifyInfo.newCol.Name))
}
}
failpoint.Inject("uninitializedOffsetAndState", func(val failpoint.Value) {
//nolint:forcetypeassert
if val.(bool) {
if modifyInfo.newCol.State != model.StatePublic {
failpoint.Return(ver, errors.New("the column state is wrong"))
}
}
})
err = checkAndApplyAutoRandomBits(d, t, dbInfo, tblInfo, oldCol, modifyInfo.newCol, modifyInfo.updatedAutoRandomBits)
if err != nil {
job.State = model.JobStateCancelled
return ver, errors.Trace(err)
}
if !needChangeColumnData(oldCol, modifyInfo.newCol) {
return w.doModifyColumn(d, t, job, dbInfo, tblInfo, modifyInfo.newCol, oldCol, modifyInfo.pos)
}
if err = isGeneratedRelatedColumn(tblInfo, modifyInfo.newCol, oldCol); err != nil {
job.State = model.JobStateCancelled
return ver, errors.Trace(err)
}
changingCol := modifyInfo.changingCol
if changingCol == nil {
newColName := model.NewCIStr(genChangingColumnUniqueName(tblInfo, oldCol))
if mysql.HasPriKeyFlag(oldCol.GetFlag()) {
job.State = model.JobStateCancelled
msg := "this column has primary key flag"
return ver, dbterror.ErrUnsupportedModifyColumn.GenWithStackByArgs(msg)
}
changingCol = modifyInfo.newCol.Clone()
changingCol.Name = newColName
changingCol.ChangeStateInfo = &model.ChangeStateInfo{DependencyColumnOffset: oldCol.Offset}
originDefVal, err := GetOriginDefaultValueForModifyColumn(newContext(d.store), changingCol, oldCol)
if err != nil {
return ver, errors.Trace(err)
}
if err = changingCol.SetOriginDefaultValue(originDefVal); err != nil {
return ver, errors.Trace(err)
}
InitAndAddColumnToTable(tblInfo, changingCol)
indexesToChange := FindRelatedIndexesToChange(tblInfo, oldCol.Name)
for _, info := range indexesToChange {
newIdxID := AllocateIndexID(tblInfo)
if !info.isTemp {
// We create a temp index for each normal index.
tmpIdx := info.IndexInfo.Clone()
tmpIdxName := genChangingIndexUniqueName(tblInfo, info.IndexInfo)
setIdxIDName(tmpIdx, newIdxID, model.NewCIStr(tmpIdxName))
SetIdxColNameOffset(tmpIdx.Columns[info.Offset], changingCol)
tblInfo.Indices = append(tblInfo.Indices, tmpIdx)
} else {
// The index is a temp index created by previous modify column job(s).
// We can overwrite it to reduce reorg cost, because it will be dropped eventually.
tmpIdx := info.IndexInfo
oldTempIdxID := tmpIdx.ID
setIdxIDName(tmpIdx, newIdxID, tmpIdx.Name /* unchanged */)
SetIdxColNameOffset(tmpIdx.Columns[info.Offset], changingCol)
modifyInfo.removedIdxs = append(modifyInfo.removedIdxs, oldTempIdxID)
}
}
} else {
changingCol = model.FindColumnInfoByID(tblInfo.Columns, modifyInfo.changingCol.ID)
if changingCol == nil {
logutil.BgLogger().Error("[ddl] the changing column has been removed", zap.Error(err))
job.State = model.JobStateCancelled
return ver, errors.Trace(infoschema.ErrColumnNotExists.GenWithStackByArgs(oldCol.Name, tblInfo.Name))
}
}
return w.doModifyColumnTypeWithData(d, t, job, dbInfo, tblInfo, changingCol, oldCol, modifyInfo.newCol.Name, modifyInfo.pos, modifyInfo.removedIdxs)
}
func setIdxIDName(idxInfo *model.IndexInfo, newID int64, newName model.CIStr) {
idxInfo.ID = newID
idxInfo.Name = newName
}
// SetIdxColNameOffset sets index column name and offset from changing ColumnInfo.
func SetIdxColNameOffset(idxCol *model.IndexColumn, changingCol *model.ColumnInfo) {
idxCol.Name = changingCol.Name
idxCol.Offset = changingCol.Offset
canPrefix := types.IsTypePrefixable(changingCol.GetType())
if !canPrefix || (changingCol.GetFlen() < idxCol.Length) {
idxCol.Length = types.UnspecifiedLength
}
}
// rollbackModifyColumnJobWithData is used to rollback modify-column job which need to reorg the data.
func rollbackModifyColumnJobWithData(d *ddlCtx, t *meta.Meta, tblInfo *model.TableInfo, job *model.Job, oldCol *model.ColumnInfo, modifyInfo *modifyingColInfo) (ver int64, err error) {
// If the not-null change is included, we should clean the flag info in oldCol.
if modifyInfo.modifyColumnTp == mysql.TypeNull {
// Reset NotNullFlag flag.
tblInfo.Columns[oldCol.Offset].SetFlag(oldCol.GetFlag() &^ mysql.NotNullFlag)
// Reset PreventNullInsertFlag flag.
tblInfo.Columns[oldCol.Offset].SetFlag(oldCol.GetFlag() &^ mysql.PreventNullInsertFlag)
}
var changingIdxIDs []int64
if modifyInfo.changingCol != nil {
changingIdxIDs = buildRelatedIndexIDs(tblInfo, modifyInfo.changingCol.ID)
// The job is in the middle state. The appended changingCol and changingIndex should
// be removed from the tableInfo as well.
removeChangingColAndIdxs(tblInfo, modifyInfo.changingCol.ID)
}
ver, err = updateVersionAndTableInfoWithCheck(d, t, job, tblInfo, true)
if err != nil {
return ver, errors.Trace(err)
}
job.FinishTableJob(model.JobStateRollbackDone, model.StateNone, ver, tblInfo)
// Reconstruct the job args to add the temporary index ids into delete range table.
job.Args = []interface{}{changingIdxIDs, getPartitionIDs(tblInfo)}
return ver, nil
}
func removeChangingColAndIdxs(tblInfo *model.TableInfo, changingColID int64) {
restIdx := tblInfo.Indices[:0]
for _, idx := range tblInfo.Indices {
if !idx.HasColumnInIndexColumns(tblInfo, changingColID) {
restIdx = append(restIdx, idx)
}
}
tblInfo.Indices = restIdx
restCols := tblInfo.Columns[:0]
for _, c := range tblInfo.Columns {
if c.ID != changingColID {
restCols = append(restCols, c)
}
}
tblInfo.Columns = restCols
}
func (w *worker) doModifyColumnTypeWithData(
d *ddlCtx, t *meta.Meta, job *model.Job,
dbInfo *model.DBInfo, tblInfo *model.TableInfo, changingCol, oldCol *model.ColumnInfo,
colName model.CIStr, pos *ast.ColumnPosition, rmIdxIDs []int64) (ver int64, _ error) {
var err error
originalState := changingCol.State
targetCol := changingCol.Clone()
targetCol.Name = colName
changingIdxs := buildRelatedIndexInfos(tblInfo, changingCol.ID)
switch changingCol.State {
case model.StateNone:
// Column from null to not null.
if !mysql.HasNotNullFlag(oldCol.GetFlag()) && mysql.HasNotNullFlag(changingCol.GetFlag()) {
// Introduce the `mysql.PreventNullInsertFlag` flag to prevent users from inserting or updating null values.
err := modifyColsFromNull2NotNull(w, dbInfo, tblInfo, []*model.ColumnInfo{oldCol}, targetCol, oldCol.GetType() != changingCol.GetType())
if err != nil {
if dbterror.ErrWarnDataTruncated.Equal(err) || dbterror.ErrInvalidUseOfNull.Equal(err) {
job.State = model.JobStateRollingback
}
return ver, err
}
}
// none -> delete only
updateChangingObjState(changingCol, changingIdxs, model.StateDeleteOnly)
failpoint.Inject("mockInsertValueAfterCheckNull", func(val failpoint.Value) {
if valStr, ok := val.(string); ok {
var sctx sessionctx.Context
sctx, err := w.sessPool.get()
if err != nil {
failpoint.Return(ver, err)
}
defer w.sessPool.put(sctx)
ctx := kv.WithInternalSourceType(context.Background(), kv.InternalTxnDDL)
//nolint:forcetypeassert
_, _, err = sctx.(sqlexec.RestrictedSQLExecutor).ExecRestrictedSQL(ctx, nil, valStr)
if err != nil {
job.State = model.JobStateCancelled
failpoint.Return(ver, err)
}
}
})
ver, err = updateVersionAndTableInfoWithCheck(d, t, job, tblInfo, originalState != changingCol.State)
if err != nil {
return ver, errors.Trace(err)
}
// Make sure job args change after `updateVersionAndTableInfoWithCheck`, otherwise, the job args will
// be updated in `updateDDLJob` even if it meets an error in `updateVersionAndTableInfoWithCheck`.
job.SchemaState = model.StateDeleteOnly
metrics.GetBackfillProgressByLabel(metrics.LblModifyColumn, job.SchemaName, tblInfo.Name.String()).Set(0)
job.Args = append(job.Args, changingCol, changingIdxs, rmIdxIDs)
case model.StateDeleteOnly:
// Column from null to not null.
if !mysql.HasNotNullFlag(oldCol.GetFlag()) && mysql.HasNotNullFlag(changingCol.GetFlag()) {
// Introduce the `mysql.PreventNullInsertFlag` flag to prevent users from inserting or updating null values.
err := modifyColsFromNull2NotNull(w, dbInfo, tblInfo, []*model.ColumnInfo{oldCol}, targetCol, oldCol.GetType() != changingCol.GetType())
if err != nil {
if dbterror.ErrWarnDataTruncated.Equal(err) || dbterror.ErrInvalidUseOfNull.Equal(err) {
job.State = model.JobStateRollingback
}
return ver, err
}
}
// delete only -> write only
updateChangingObjState(changingCol, changingIdxs, model.StateWriteOnly)
ver, err = updateVersionAndTableInfo(d, t, job, tblInfo, originalState != changingCol.State)
if err != nil {
return ver, errors.Trace(err)
}
job.SchemaState = model.StateWriteOnly
case model.StateWriteOnly:
// write only -> reorganization
updateChangingObjState(changingCol, changingIdxs, model.StateWriteReorganization)
ver, err = updateVersionAndTableInfo(d, t, job, tblInfo, originalState != changingCol.State)
if err != nil {
return ver, errors.Trace(err)
}
// Initialize SnapshotVer to 0 for later reorganization check.
job.SnapshotVer = 0
job.SchemaState = model.StateWriteReorganization
case model.StateWriteReorganization:
tbl, err := getTable(d.store, dbInfo.ID, tblInfo)
if err != nil {
return ver, errors.Trace(err)
}
var done bool
if job.MultiSchemaInfo != nil {
done, ver, err = doReorgWorkForModifyColumnMultiSchema(w, d, t, job, tbl, oldCol, changingCol, changingIdxs)
} else {
done, ver, err = doReorgWorkForModifyColumn(w, d, t, job, tbl, oldCol, changingCol, changingIdxs)
}
if !done {
return ver, err
}
rmIdxIDs = append(buildRelatedIndexIDs(tblInfo, oldCol.ID), rmIdxIDs...)
err = adjustTableInfoAfterModifyColumnWithData(tblInfo, pos, oldCol, changingCol, colName, changingIdxs)
if err != nil {
job.State = model.JobStateRollingback
return ver, errors.Trace(err)
}
updateChangingObjState(changingCol, changingIdxs, model.StatePublic)
ver, err = updateVersionAndTableInfo(d, t, job, tblInfo, originalState != changingCol.State)
if err != nil {
return ver, errors.Trace(err)
}
// Finish this job.
job.FinishTableJob(model.JobStateDone, model.StatePublic, ver, tblInfo)
// Refactor the job args to add the old index ids into delete range table.
job.Args = []interface{}{rmIdxIDs, getPartitionIDs(tblInfo)}
asyncNotifyEvent(d, &ddlutil.Event{Tp: model.ActionModifyColumn, TableInfo: tblInfo, ColumnInfos: []*model.ColumnInfo{changingCol}})
default:
err = dbterror.ErrInvalidDDLState.GenWithStackByArgs("column", changingCol.State)
}
return ver, errors.Trace(err)
}
func doReorgWorkForModifyColumnMultiSchema(w *worker, d *ddlCtx, t *meta.Meta, job *model.Job, tbl table.Table,
oldCol, changingCol *model.ColumnInfo, changingIdxs []*model.IndexInfo) (done bool, ver int64, err error) {
if job.MultiSchemaInfo.Revertible {
done, ver, err = doReorgWorkForModifyColumn(w, d, t, job, tbl, oldCol, changingCol, changingIdxs)
if done {
// We need another round to wait for all the others sub-jobs to finish.
job.MarkNonRevertible()
}
// We need another round to run the reorg process.
return false, ver, err
}
// Non-revertible means all the sub jobs finished.
return true, ver, err
}
func doReorgWorkForModifyColumn(w *worker, d *ddlCtx, t *meta.Meta, job *model.Job, tbl table.Table,
oldCol, changingCol *model.ColumnInfo, changingIdxs []*model.IndexInfo) (done bool, ver int64, err error) {
job.ReorgMeta.ReorgTp = model.ReorgTypeTxn
rh := newReorgHandler(t, w.sess, w.concurrentDDL)
reorgInfo, err := getReorgInfo(d.jobContext(job), d, rh, job, tbl, BuildElements(changingCol, changingIdxs), false)
if err != nil || reorgInfo.first {
// If we run reorg firstly, we should update the job snapshot version
// and then run the reorg next time.
return false, ver, errors.Trace(err)
}
// Inject a failpoint so that we can pause here and do verification on other components.
// With a failpoint-enabled version of TiDB, you can trigger this failpoint by the following command:
// enable: curl -X PUT -d "pause" "http://127.0.0.1:10080/fail/github.com/pingcap/tidb/ddl/mockDelayInModifyColumnTypeWithData".
// disable: curl -X DELETE "http://127.0.0.1:10080/fail/github.com/pingcap/tidb/ddl/mockDelayInModifyColumnTypeWithData"
failpoint.Inject("mockDelayInModifyColumnTypeWithData", func() {})
err = w.runReorgJob(rh, reorgInfo, tbl.Meta(), d.lease, func() (addIndexErr error) {
defer util.Recover(metrics.LabelDDL, "onModifyColumn",
func() {
addIndexErr = dbterror.ErrCancelledDDLJob.GenWithStack("modify table `%v` column `%v` panic", tbl.Meta().Name, oldCol.Name)
}, false)
// Use old column name to generate less confusing error messages.
changingColCpy := changingCol.Clone()
changingColCpy.Name = oldCol.Name
return w.updateCurrentElement(tbl, reorgInfo)
})
if err != nil {
if dbterror.ErrWaitReorgTimeout.Equal(err) {
// If timeout, we should return, check for the owner and re-wait job done.
return false, ver, nil
}
if kv.IsTxnRetryableError(err) {
return false, ver, errors.Trace(err)
}
if err1 := rh.RemoveDDLReorgHandle(job, reorgInfo.elements); err1 != nil {
logutil.BgLogger().Warn("[ddl] run modify column job failed, RemoveDDLReorgHandle failed, can't convert job to rollback",
zap.String("job", job.String()), zap.Error(err1))
}
logutil.BgLogger().Warn("[ddl] run modify column job failed, convert job to rollback", zap.String("job", job.String()), zap.Error(err))
job.State = model.JobStateRollingback
return false, ver, errors.Trace(err)
}
return true, ver, nil
}
func adjustTableInfoAfterModifyColumnWithData(tblInfo *model.TableInfo, pos *ast.ColumnPosition,
oldCol, changingCol *model.ColumnInfo, newName model.CIStr, changingIdxs []*model.IndexInfo) (err error) {
if pos != nil && pos.RelativeColumn != nil && oldCol.Name.L == pos.RelativeColumn.Name.L {
// For cases like `modify column b after b`, it should report this error.
return errors.Trace(infoschema.ErrColumnNotExists.GenWithStackByArgs(oldCol.Name, tblInfo.Name))
}
internalColName := changingCol.Name
changingCol = replaceOldColumn(tblInfo, oldCol, changingCol, newName)
if len(changingIdxs) > 0 {
updateNewIdxColsNameOffset(changingIdxs, internalColName, changingCol)
indexesToRemove := filterIndexesToRemove(changingIdxs, newName, tblInfo)
replaceOldIndexes(tblInfo, indexesToRemove)
}
// Move the new column to a correct offset.
destOffset, err := LocateOffsetToMove(changingCol.Offset, pos, tblInfo)
if err != nil {
return errors.Trace(err)
}
tblInfo.MoveColumnInfo(changingCol.Offset, destOffset)
return nil
}
func replaceOldColumn(tblInfo *model.TableInfo, oldCol, changingCol *model.ColumnInfo,
newName model.CIStr) *model.ColumnInfo {
tblInfo.MoveColumnInfo(changingCol.Offset, len(tblInfo.Columns)-1)
changingCol = updateChangingCol(changingCol, newName, oldCol.Offset)
tblInfo.Columns[oldCol.Offset] = changingCol
tblInfo.Columns = tblInfo.Columns[:len(tblInfo.Columns)-1]
return changingCol
}
func replaceOldIndexes(tblInfo *model.TableInfo, changingIdxs []*model.IndexInfo) {
// Remove the changing indexes.
for i, idx := range tblInfo.Indices {
for _, cIdx := range changingIdxs {
if cIdx.ID == idx.ID {
tblInfo.Indices[i] = nil
break
}
}
}
tmp := tblInfo.Indices[:0]
for _, idx := range tblInfo.Indices {
if idx != nil {
tmp = append(tmp, idx)
}
}
tblInfo.Indices = tmp
// Replace the old indexes with changing indexes.
for _, cIdx := range changingIdxs {
// The index name should be changed from '_Idx$_name' to 'name'.
idxName := getChangingIndexOriginName(cIdx)
for i, idx := range tblInfo.Indices {
if strings.EqualFold(idxName, idx.Name.O) {
cIdx.Name = model.NewCIStr(idxName)
tblInfo.Indices[i] = cIdx
break
}
}
}
}
// updateNewIdxColsNameOffset updates the name&offset of the index column.
func updateNewIdxColsNameOffset(changingIdxs []*model.IndexInfo,
oldName model.CIStr, changingCol *model.ColumnInfo) {
for _, idx := range changingIdxs {
for _, col := range idx.Columns {
if col.Name.L == oldName.L {
SetIdxColNameOffset(col, changingCol)
}
}
}
}
// filterIndexesToRemove filters out the indexes that can be removed.
func filterIndexesToRemove(changingIdxs []*model.IndexInfo, colName model.CIStr, tblInfo *model.TableInfo) []*model.IndexInfo {
indexesToRemove := make([]*model.IndexInfo, 0, len(changingIdxs))
for _, idx := range changingIdxs {
var hasOtherChangingCol bool
for _, col := range idx.Columns {
if col.Name.L == colName.L {
continue // ignore the current modifying column.
}
if !hasOtherChangingCol {
hasOtherChangingCol = tblInfo.Columns[col.Offset].ChangeStateInfo != nil
}
}
// For the indexes that still contains other changing column, skip removing it now.
// We leave the removal work to the last modify column job.
if !hasOtherChangingCol {
indexesToRemove = append(indexesToRemove, idx)
}
}
return indexesToRemove
}
func updateChangingCol(col *model.ColumnInfo, newName model.CIStr, newOffset int) *model.ColumnInfo {
col.Name = newName
col.ChangeStateInfo = nil
col.Offset = newOffset
// After changing the column, the column's type is change, so it needs to set OriginDefaultValue back
// so that there is no error in getting the default value from OriginDefaultValue.
// Besides, nil data that was not backfilled in the "add column" is backfilled after the column is changed.
// So it can set OriginDefaultValue to nil.
col.OriginDefaultValue = nil
return col
}
func buildRelatedIndexInfos(tblInfo *model.TableInfo, colID int64) []*model.IndexInfo {
var indexInfos []*model.IndexInfo
for _, idx := range tblInfo.Indices {
if idx.HasColumnInIndexColumns(tblInfo, colID) {
indexInfos = append(indexInfos, idx)
}
}
return indexInfos
}
func buildRelatedIndexIDs(tblInfo *model.TableInfo, colID int64) []int64 {
var oldIdxIDs []int64
for _, idx := range tblInfo.Indices {
if idx.HasColumnInIndexColumns(tblInfo, colID) {
oldIdxIDs = append(oldIdxIDs, idx.ID)
}
}
return oldIdxIDs
}
// LocateOffsetToMove returns the offset of the column to move.
func LocateOffsetToMove(currentOffset int, pos *ast.ColumnPosition, tblInfo *model.TableInfo) (destOffset int, err error) {
if pos == nil {
return currentOffset, nil
}
// Get column offset.
switch pos.Tp {
case ast.ColumnPositionFirst:
return 0, nil
case ast.ColumnPositionAfter:
c := model.FindColumnInfo(tblInfo.Columns, pos.RelativeColumn.Name.L)
if c == nil || c.State != model.StatePublic {
return 0, infoschema.ErrColumnNotExists.GenWithStackByArgs(pos.RelativeColumn, tblInfo.Name)
}
if currentOffset <= c.Offset {
return c.Offset, nil
}
return c.Offset + 1, nil
case ast.ColumnPositionNone:
return currentOffset, nil
default:
return 0, errors.Errorf("unknown column position type")
}
}
// BuildElements is exported for testing.
func BuildElements(changingCol *model.ColumnInfo, changingIdxs []*model.IndexInfo) []*meta.Element {
elements := make([]*meta.Element, 0, len(changingIdxs)+1)
elements = append(elements, &meta.Element{ID: changingCol.ID, TypeKey: meta.ColumnElementKey})
for _, idx := range changingIdxs {