tidb rollingback 源码
tidb rollingback 代码
文件路径：/ddl/rollingback.go
// Copyright 2018 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 (
"fmt"
"github.com/pingcap/errors"
"github.com/pingcap/failpoint"
"github.com/pingcap/tidb/meta"
"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/variable"
"github.com/pingcap/tidb/util/dbterror"
"github.com/pingcap/tidb/util/logutil"
"go.uber.org/zap"
)
// UpdateColsNull2NotNull changes the null option of columns of an index.
func UpdateColsNull2NotNull(tblInfo *model.TableInfo, indexInfo *model.IndexInfo) error {
nullCols, err := getNullColInfos(tblInfo, indexInfo)
if err != nil {
return errors.Trace(err)
}
for _, col := range nullCols {
col.AddFlag(mysql.NotNullFlag)
col.DelFlag(mysql.PreventNullInsertFlag)
}
return nil
}
func convertAddIdxJob2RollbackJob(d *ddlCtx, t *meta.Meta, job *model.Job, tblInfo *model.TableInfo, indexInfo *model.IndexInfo, err error) (int64, error) {
failpoint.Inject("mockConvertAddIdxJob2RollbackJobError", func(val failpoint.Value) {
if val.(bool) {
failpoint.Return(0, errors.New("mock convert add index job to rollback job error"))
}
})
if indexInfo.Primary {
nullCols, err := getNullColInfos(tblInfo, indexInfo)
if err != nil {
return 0, errors.Trace(err)
}
for _, col := range nullCols {
// Field PreventNullInsertFlag flag reset.
col.DelFlag(mysql.PreventNullInsertFlag)
}
}
// the second and the third args will be used in onDropIndex.
job.Args = []interface{}{indexInfo.Name, false /* ifExists */, getPartitionIDs(tblInfo)}
// If add index job rollbacks in write reorganization state, its need to delete all keys which has been added.
// Its work is the same as drop index job do.
// The write reorganization state in add index job that likes write only state in drop index job.
// So the next state is delete only state.
originalState := indexInfo.State
indexInfo.State = model.StateDeleteOnly
job.SchemaState = model.StateDeleteOnly
ver, err1 := updateVersionAndTableInfo(d, t, job, tblInfo, originalState != indexInfo.State)
if err1 != nil {
return ver, errors.Trace(err1)
}
job.State = model.JobStateRollingback
return ver, errors.Trace(err)
}
// convertNotReorgAddIdxJob2RollbackJob converts the add index job that are not started workers to rollingbackJob,
// to rollback add index operations. job.SnapshotVer == 0 indicates the workers are not started.
func convertNotReorgAddIdxJob2RollbackJob(d *ddlCtx, t *meta.Meta, job *model.Job, occuredErr error) (ver int64, err error) {
schemaID := job.SchemaID
tblInfo, err := GetTableInfoAndCancelFaultJob(t, job, schemaID)
if err != nil {
return ver, errors.Trace(err)
}
var (
unique bool
indexName model.CIStr
indexPartSpecifications []*ast.IndexPartSpecification
indexOption *ast.IndexOption
)
err = job.DecodeArgs(&unique, &indexName, &indexPartSpecifications, &indexOption)
if err != nil {
job.State = model.JobStateCancelled
return ver, errors.Trace(err)
}
indexInfo := tblInfo.FindIndexByName(indexName.L)
if indexInfo == nil {
job.State = model.JobStateCancelled
return ver, dbterror.ErrCancelledDDLJob
}
return convertAddIdxJob2RollbackJob(d, t, job, tblInfo, indexInfo, occuredErr)
}
// rollingbackModifyColumn change the modifying-column job into rolling back state.
// Since modifying column job has two types: normal-type and reorg-type, we should handle it respectively.
// normal-type has only two states: None -> Public
// reorg-type has five states: None -> Delete-only -> Write-only -> Write-org -> Public
func rollingbackModifyColumn(w *worker, d *ddlCtx, t *meta.Meta, job *model.Job) (ver int64, err error) {
if needNotifyAndStopReorgWorker(job) {
// column type change workers are started. we have to ask them to exit.
logutil.Logger(w.logCtx).Info("[ddl] run the cancelling DDL job", zap.String("job", job.String()))
d.notifyReorgCancel(job)
// Give the this kind of ddl one more round to run, the dbterror.ErrCancelledDDLJob should be fetched from the bottom up.
return w.onModifyColumn(d, t, job)
}
_, tblInfo, oldCol, jp, err := getModifyColumnInfo(t, job)
if err != nil {
return ver, err
}
if !needChangeColumnData(oldCol, jp.newCol) {
// Normal-type rolling back
if job.SchemaState == model.StateNone {
// When change null to not null, although state is unchanged with none, the oldCol flag's has been changed to preNullInsertFlag.
// To roll back this kind of normal job, it is necessary to mark the state as JobStateRollingback to restore the old col's flag.
if jp.modifyColumnTp == mysql.TypeNull && tblInfo.Columns[oldCol.Offset].GetFlag()|mysql.PreventNullInsertFlag != 0 {
job.State = model.JobStateRollingback
return ver, dbterror.ErrCancelledDDLJob
}
// Normal job with stateNone can be cancelled directly.
job.State = model.JobStateCancelled
return ver, dbterror.ErrCancelledDDLJob
}
// StatePublic couldn't be cancelled.
job.State = model.JobStateRunning
return ver, nil
}
// reorg-type rolling back
if jp.changingCol == nil {
// The job hasn't been handled and we cancel it directly.
job.State = model.JobStateCancelled
return ver, dbterror.ErrCancelledDDLJob
}
// The job has been in its middle state (but the reorg worker hasn't started) and we roll it back here.
job.State = model.JobStateRollingback
return ver, dbterror.ErrCancelledDDLJob
}
func rollingbackAddColumn(d *ddlCtx, t *meta.Meta, job *model.Job) (ver int64, err error) {
tblInfo, columnInfo, col, _, _, err := checkAddColumn(t, job)
if err != nil {
return ver, errors.Trace(err)
}
if columnInfo == nil {
job.State = model.JobStateCancelled
return ver, dbterror.ErrCancelledDDLJob
}
originalState := columnInfo.State
columnInfo.State = model.StateDeleteOnly
job.SchemaState = model.StateDeleteOnly
job.Args = []interface{}{col.Name}
ver, err = updateVersionAndTableInfo(d, t, job, tblInfo, originalState != columnInfo.State)
if err != nil {
return ver, errors.Trace(err)
}
job.State = model.JobStateRollingback
return ver, dbterror.ErrCancelledDDLJob
}
func rollingbackDropColumn(d *ddlCtx, t *meta.Meta, job *model.Job) (ver int64, err error) {
_, colInfo, idxInfos, _, err := checkDropColumn(d, t, job)
if err != nil {
return ver, errors.Trace(err)
}
for _, indexInfo := range idxInfos {
switch indexInfo.State {
case model.StateWriteOnly, model.StateDeleteOnly, model.StateDeleteReorganization, model.StateNone:
// We can not rollback now, so just continue to drop index.
// In function isJobRollbackable will let job rollback when state is StateNone.
// When there is no index related to the drop column job it is OK, but when there has indices, we should
// make sure the job is not rollback.
job.State = model.JobStateRunning
return ver, nil
case model.StatePublic:
default:
return ver, dbterror.ErrInvalidDDLState.GenWithStackByArgs("index", indexInfo.State)
}
}
// StatePublic means when the job is not running yet.
if colInfo.State == model.StatePublic {
job.State = model.JobStateCancelled
return ver, dbterror.ErrCancelledDDLJob
}
// In the state of drop column `write only -> delete only -> reorganization`,
// We can not rollback now, so just continue to drop column.
job.State = model.JobStateRunning
return ver, nil
}
func rollingbackDropIndex(d *ddlCtx, t *meta.Meta, job *model.Job) (ver int64, err error) {
_, indexInfo, _, err := checkDropIndex(d, t, job)
if err != nil {
return ver, errors.Trace(err)
}
switch indexInfo.State {
case model.StateWriteOnly, model.StateDeleteOnly, model.StateDeleteReorganization, model.StateNone:
// We can not rollback now, so just continue to drop index.
// Normally won't fetch here, because there is check when cancel ddl jobs. see function: isJobRollbackable.
job.State = model.JobStateRunning
return ver, nil
case model.StatePublic:
job.State = model.JobStateCancelled
return ver, dbterror.ErrCancelledDDLJob
default:
return ver, dbterror.ErrInvalidDDLState.GenWithStackByArgs("index", indexInfo.State)
}
}
func rollingbackAddIndex(w *worker, d *ddlCtx, t *meta.Meta, job *model.Job, isPK bool) (ver int64, err error) {
if needNotifyAndStopReorgWorker(job) {
// add index workers are started. need to ask them to exit.
logutil.Logger(w.logCtx).Info("[ddl] run the cancelling DDL job", zap.String("job", job.String()))
d.notifyReorgCancel(job)
ver, err = w.onCreateIndex(d, t, job, isPK)
} else {
// add index's reorg workers are not running, remove the indexInfo in tableInfo.
ver, err = convertNotReorgAddIdxJob2RollbackJob(d, t, job, dbterror.ErrCancelledDDLJob)
}
return
}
func needNotifyAndStopReorgWorker(job *model.Job) bool {
if job.SchemaState == model.StateWriteReorganization && job.SnapshotVer != 0 {
// If the value of SnapshotVer isn't zero, it means the reorg workers have been started.
if job.MultiSchemaInfo != nil {
// However, if the sub-job is non-revertible, it means the reorg process is finished.
// We don't need to start another round to notify reorg workers to exit.
return job.MultiSchemaInfo.Revertible
}
return true
}
return false
}
func convertAddTablePartitionJob2RollbackJob(d *ddlCtx, t *meta.Meta, job *model.Job, otherwiseErr error, tblInfo *model.TableInfo) (ver int64, err error) {
addingDefinitions := tblInfo.Partition.AddingDefinitions
partNames := make([]string, 0, len(addingDefinitions))
for _, pd := range addingDefinitions {
partNames = append(partNames, pd.Name.L)
}
job.Args = []interface{}{partNames}
ver, err = updateVersionAndTableInfo(d, t, job, tblInfo, true)
if err != nil {
return ver, errors.Trace(err)
}
job.State = model.JobStateRollingback
return ver, errors.Trace(otherwiseErr)
}
func rollingbackAddTablePartition(d *ddlCtx, t *meta.Meta, job *model.Job) (ver int64, err error) {
tblInfo, _, addingDefinitions, err := checkAddPartition(t, job)
if err != nil {
return ver, errors.Trace(err)
}
// addingDefinitions' len = 0 means the job hasn't reached the replica-only state.
if len(addingDefinitions) == 0 {
job.State = model.JobStateCancelled
return ver, errors.Trace(dbterror.ErrCancelledDDLJob)
}
// addingDefinitions is also in tblInfo, here pass the tblInfo as parameter directly.
return convertAddTablePartitionJob2RollbackJob(d, t, job, dbterror.ErrCancelledDDLJob, tblInfo)
}
func rollingbackDropTableOrView(t *meta.Meta, job *model.Job) error {
tblInfo, err := checkTableExistAndCancelNonExistJob(t, job, job.SchemaID)
if err != nil {
return errors.Trace(err)
}
// To simplify the rollback logic, cannot be canceled after job start to run.
// Normally won't fetch here, because there is check when cancel ddl jobs. see function: isJobRollbackable.
if tblInfo.State == model.StatePublic {
job.State = model.JobStateCancelled
return dbterror.ErrCancelledDDLJob
}
job.State = model.JobStateRunning
return nil
}
func rollingbackDropTablePartition(t *meta.Meta, job *model.Job) (ver int64, err error) {
_, err = GetTableInfoAndCancelFaultJob(t, job, job.SchemaID)
if err != nil {
return ver, errors.Trace(err)
}
return cancelOnlyNotHandledJob(job, model.StatePublic)
}
func rollingbackDropSchema(t *meta.Meta, job *model.Job) error {
dbInfo, err := checkSchemaExistAndCancelNotExistJob(t, job)
if err != nil {
return errors.Trace(err)
}
// To simplify the rollback logic, cannot be canceled after job start to run.
// Normally won't fetch here, because there is check when cancel ddl jobs. see function: isJobRollbackable.
if dbInfo.State == model.StatePublic {
job.State = model.JobStateCancelled
return dbterror.ErrCancelledDDLJob
}
job.State = model.JobStateRunning
return nil
}
func rollingbackRenameIndex(t *meta.Meta, job *model.Job) (ver int64, err error) {
tblInfo, from, _, err := checkRenameIndex(t, job)
if err != nil {
return ver, errors.Trace(err)
}
// Here rename index is done in a transaction, if the job is not completed, it can be canceled.
idx := tblInfo.FindIndexByName(from.L)
if idx.State == model.StatePublic {
job.State = model.JobStateCancelled
return ver, dbterror.ErrCancelledDDLJob
}
job.State = model.JobStateRunning
return ver, errors.Trace(err)
}
func cancelOnlyNotHandledJob(job *model.Job, initialState model.SchemaState) (ver int64, err error) {
// We can only cancel the not handled job.
if job.SchemaState == initialState {
job.State = model.JobStateCancelled
return ver, dbterror.ErrCancelledDDLJob
}
job.State = model.JobStateRunning
return ver, nil
}
func rollingbackTruncateTable(t *meta.Meta, job *model.Job) (ver int64, err error) {
_, err = GetTableInfoAndCancelFaultJob(t, job, job.SchemaID)
if err != nil {
return ver, errors.Trace(err)
}
return cancelOnlyNotHandledJob(job, model.StateNone)
}
func convertJob2RollbackJob(w *worker, d *ddlCtx, t *meta.Meta, job *model.Job) (ver int64, err error) {
switch job.Type {
case model.ActionAddColumn:
ver, err = rollingbackAddColumn(d, t, job)
case model.ActionAddIndex:
ver, err = rollingbackAddIndex(w, d, t, job, false)
case model.ActionAddPrimaryKey:
ver, err = rollingbackAddIndex(w, d, t, job, true)
case model.ActionAddTablePartition:
ver, err = rollingbackAddTablePartition(d, t, job)
case model.ActionDropColumn:
ver, err = rollingbackDropColumn(d, t, job)
case model.ActionDropIndex, model.ActionDropPrimaryKey:
ver, err = rollingbackDropIndex(d, t, job)
case model.ActionDropTable, model.ActionDropView, model.ActionDropSequence:
err = rollingbackDropTableOrView(t, job)
case model.ActionDropTablePartition:
ver, err = rollingbackDropTablePartition(t, job)
case model.ActionDropSchema:
err = rollingbackDropSchema(t, job)
case model.ActionRenameIndex:
ver, err = rollingbackRenameIndex(t, job)
case model.ActionTruncateTable:
ver, err = rollingbackTruncateTable(t, job)
case model.ActionModifyColumn:
ver, err = rollingbackModifyColumn(w, d, t, job)
case model.ActionDropForeignKey:
ver, err = cancelOnlyNotHandledJob(job, model.StatePublic)
case model.ActionRebaseAutoID, model.ActionShardRowID, model.ActionAddForeignKey,
model.ActionRenameTable, model.ActionRenameTables,
model.ActionModifyTableCharsetAndCollate, model.ActionTruncateTablePartition,
model.ActionModifySchemaCharsetAndCollate, model.ActionRepairTable,
model.ActionModifyTableAutoIdCache, model.ActionAlterIndexVisibility,
model.ActionExchangeTablePartition, model.ActionModifySchemaDefaultPlacement:
ver, err = cancelOnlyNotHandledJob(job, model.StateNone)
case model.ActionMultiSchemaChange:
err = rollingBackMultiSchemaChange(job)
default:
job.State = model.JobStateCancelled
err = dbterror.ErrCancelledDDLJob
}
if err != nil {
if job.Error == nil {
job.Error = toTError(err)
}
job.ErrorCount++
if dbterror.ErrCancelledDDLJob.Equal(err) {
// The job is normally cancelled.
if !job.Error.Equal(dbterror.ErrCancelledDDLJob) {
job.Error = terror.GetErrClass(job.Error).Synthesize(terror.ErrCode(job.Error.Code()),
fmt.Sprintf("DDL job rollback, error msg: %s", terror.ToSQLError(job.Error).Message))
}
} else {
// A job canceling meet other error.
//
// Once `convertJob2RollbackJob` meets an error, the job state can't be set as `JobStateRollingback` since
// job state and args may not be correctly overwritten. The job will be fetched to run with the cancelling
// state again. So we should check the error count here.
if err1 := loadDDLVars(w); err1 != nil {
logutil.Logger(w.logCtx).Error("[ddl] load DDL global variable failed", zap.Error(err1))
}
errorCount := variable.GetDDLErrorCountLimit()
if job.ErrorCount > errorCount {
logutil.Logger(w.logCtx).Warn("[ddl] rollback DDL job error count exceed the limit, cancelled it now", zap.Int64("jobID", job.ID), zap.Int64("errorCountLimit", errorCount))
job.Error = toTError(errors.Errorf("rollback DDL job error count exceed the limit %d, cancelled it now", errorCount))
job.State = model.JobStateCancelled
}
}
if job.State != model.JobStateRollingback && job.State != model.JobStateCancelled {
logutil.Logger(w.logCtx).Error("[ddl] run DDL job failed", zap.String("job", job.String()), zap.Error(err))
} else {
logutil.Logger(w.logCtx).Info("[ddl] the DDL job is cancelled normally", zap.String("job", job.String()), zap.Error(err))
// If job is cancelled, we shouldn't return an error.
return ver, nil
}
}
return
}
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