Files
tidb/pkg/ddl/multi_schema_change.go
2025-01-07 10:20:04 +00:00

457 lines
15 KiB
Go

// Copyright 2022 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 (
"github.com/pingcap/tidb/pkg/meta"
"github.com/pingcap/tidb/pkg/meta/model"
"github.com/pingcap/tidb/pkg/parser/ast"
"github.com/pingcap/tidb/pkg/parser/terror"
"github.com/pingcap/tidb/pkg/sessionctx"
"github.com/pingcap/tidb/pkg/table"
"github.com/pingcap/tidb/pkg/util/dbterror"
"github.com/pingcap/tidb/pkg/util/intest"
)
func onMultiSchemaChange(w *worker, jobCtx *jobContext, job *model.Job) (ver int64, err error) {
metaMut := jobCtx.metaMut
if job.MultiSchemaInfo.Revertible {
// Handle the rolling back job.
if job.IsRollingback() {
// Rollback/cancel the sub-jobs in reverse order.
for i := len(job.MultiSchemaInfo.SubJobs) - 1; i >= 0; i-- {
sub := job.MultiSchemaInfo.SubJobs[i]
if sub.IsFinished() {
continue
}
proxyJob := sub.ToProxyJob(job, i)
ver, _, err = w.runOneJobStep(jobCtx, &proxyJob, nil)
err = handleRollbackException(err, proxyJob.Error)
if err != nil {
return ver, err
}
sub.FromProxyJob(&proxyJob, ver)
return ver, nil
}
// The last rollback/cancelling sub-job is done.
job.State = model.JobStateRollbackDone
return ver, nil
}
// The sub-jobs are normally running.
// Run the first executable sub-job.
for i, sub := range job.MultiSchemaInfo.SubJobs {
if !sub.Revertible || sub.IsFinished() {
// Skip the sub-jobs which related schema states
// are in the last revertible point.
// If a sub job is finished here, it should be a noop job.
continue
}
proxyJob := sub.ToProxyJob(job, i)
ver, _, err = w.runOneJobStep(jobCtx, &proxyJob, nil)
sub.FromProxyJob(&proxyJob, ver)
handleRevertibleException(job, sub, proxyJob.Error)
return ver, err
}
// Save table info and sub-jobs for rolling back.
var tblInfo *model.TableInfo
tblInfo, err = metaMut.GetTable(job.SchemaID, job.TableID)
if err != nil {
return ver, err
}
var schemaVersionGenerated = false
subJobs := make([]model.SubJob, len(job.MultiSchemaInfo.SubJobs))
// Step the sub-jobs to the non-revertible states all at once.
// We only generate 1 schema version for these sub-job.
actionTypes := make([]model.ActionType, 0, len(job.MultiSchemaInfo.SubJobs))
for i, sub := range job.MultiSchemaInfo.SubJobs {
if sub.IsFinished() {
continue
}
subJobs[i] = *sub
proxyJob := sub.ToProxyJob(job, i)
if schemaVersionGenerated {
proxyJob.MultiSchemaInfo.SkipVersion = true
}
proxyJobVer, _, err := w.runOneJobStep(jobCtx, &proxyJob, nil)
if !schemaVersionGenerated && proxyJobVer != 0 {
schemaVersionGenerated = true
ver = proxyJobVer
}
sub.FromProxyJob(&proxyJob, proxyJobVer)
if err != nil || proxyJob.Error != nil {
for j := i - 1; j >= 0; j-- {
// TODO if some sub-job is finished, this will empty them
// also some sub-job cannot be rollback completely, maybe keep them?
job.MultiSchemaInfo.SubJobs[j] = &subJobs[j]
}
handleRevertibleException(job, sub, proxyJob.Error)
// The TableInfo and sub-jobs should be restored
// because some schema changes update the transaction aggressively.
// TODO this error handling cannot handle below case:
// suppose the job is for "alter table t auto_increment = 100, add column c int".
// if we fail on "add column c int", the allocator is rebased to 100
// which cannot be rollback, but it's table-info.AutoIncID is rollback by below call.
// TODO we should also change schema diff of 'ver' if len(actionTypes) > 1.
return updateVersionAndTableInfo(jobCtx, job, tblInfo, true)
}
actionTypes = append(actionTypes, sub.Type)
}
if len(actionTypes) > 1 {
// only single table schema changes can be put into a multi-schema-change
// job except AddForeignKey which is handled separately in the first loop.
// so this diff is enough, but it wound be better to accumulate all the diffs,
// and then merge them into a single diff.
if err = metaMut.SetSchemaDiff(&model.SchemaDiff{
Version: ver,
Type: job.Type,
TableID: job.TableID,
SchemaID: job.SchemaID,
SubActionTypes: actionTypes,
}); err != nil {
return ver, err
}
}
// All the sub-jobs are non-revertible.
job.MarkNonRevertible()
return ver, err
}
// Run the rest non-revertible sub-jobs one by one.
for i, sub := range job.MultiSchemaInfo.SubJobs {
if sub.IsFinished() {
continue
}
proxyJob := sub.ToProxyJob(job, i)
ver, _, err = w.runOneJobStep(jobCtx, &proxyJob, nil)
sub.FromProxyJob(&proxyJob, ver)
return ver, err
}
return finishMultiSchemaJob(job, metaMut)
}
func handleRevertibleException(job *model.Job, subJob *model.SubJob, err *terror.Error) {
if subJob.IsNormal() {
return
}
job.State = model.JobStateRollingback
job.Error = err
// Flush the cancelling state and cancelled state to sub-jobs.
for _, sub := range job.MultiSchemaInfo.SubJobs {
switch sub.State {
case model.JobStateRunning:
sub.State = model.JobStateCancelling
case model.JobStateNone, model.JobStateQueueing:
sub.State = model.JobStateCancelled
}
}
}
func handleRollbackException(runJobErr error, proxyJobErr *terror.Error) error {
if runJobErr != nil {
// The physical errors are not recoverable during rolling back.
// We keep retrying it.
return runJobErr
}
if proxyJobErr != nil {
if proxyJobErr.Equal(dbterror.ErrCancelledDDLJob) {
// A cancelled DDL error is normal during rolling back.
return nil
}
return proxyJobErr
}
return nil
}
func appendToSubJobs(m *model.MultiSchemaInfo, jobW *JobWrapper) error {
err := fillMultiSchemaInfo(m, jobW)
if err != nil {
return err
}
var reorgTp model.ReorgType
if jobW.ReorgMeta != nil {
reorgTp = jobW.ReorgMeta.ReorgTp
}
m.SubJobs = append(m.SubJobs, &model.SubJob{
Type: jobW.Type,
JobArgs: jobW.JobArgs,
RawArgs: jobW.RawArgs,
SchemaState: jobW.SchemaState,
SnapshotVer: jobW.SnapshotVer,
Revertible: true,
CtxVars: jobW.CtxVars,
ReorgTp: reorgTp,
})
return nil
}
func fillMultiSchemaInfo(info *model.MultiSchemaInfo, job *JobWrapper) error {
switch job.Type {
case model.ActionAddColumn:
args := job.JobArgs.(*model.TableColumnArgs)
col, pos := args.Col, args.Pos
info.AddColumns = append(info.AddColumns, col.Name)
for colName := range col.Dependences {
info.RelativeColumns = append(info.RelativeColumns, ast.CIStr{L: colName, O: colName})
}
if pos != nil && pos.Tp == ast.ColumnPositionAfter {
info.PositionColumns = append(info.PositionColumns, pos.RelativeColumn.Name)
}
case model.ActionDropColumn:
colName := job.JobArgs.(*model.TableColumnArgs).Col.Name
info.DropColumns = append(info.DropColumns, colName)
case model.ActionDropIndex, model.ActionDropPrimaryKey:
args := job.JobArgs.(*model.ModifyIndexArgs)
info.DropIndexes = append(info.DropIndexes, args.IndexArgs[0].IndexName)
case model.ActionAddIndex, model.ActionAddPrimaryKey:
args := job.JobArgs.(*model.ModifyIndexArgs)
// This job has not been merged, len(args) should be one.
intest.Assert(len(args.IndexArgs) == 1, "len(args.IndexArgs) != 1")
indexArg := args.IndexArgs[0]
info.AddIndexes = append(info.AddIndexes, indexArg.IndexName)
for _, indexPartSpecification := range indexArg.IndexPartSpecifications {
info.RelativeColumns = append(info.RelativeColumns, indexPartSpecification.Column.Name)
}
for _, c := range indexArg.HiddenCols {
for depColName := range c.Dependences {
info.RelativeColumns = append(info.RelativeColumns, ast.NewCIStr(depColName))
}
}
case model.ActionRenameIndex:
args := job.JobArgs.(*model.ModifyIndexArgs)
from, to := args.GetRenameIndexes()
info.AddIndexes = append(info.AddIndexes, from)
info.DropIndexes = append(info.DropIndexes, to)
case model.ActionModifyColumn:
args := job.JobArgs.(*model.ModifyColumnArgs)
newCol, oldColName, pos := args.Column, args.OldColumnName, args.Position
if newCol.Name.L != oldColName.L {
info.AddColumns = append(info.AddColumns, newCol.Name)
info.DropColumns = append(info.DropColumns, oldColName)
} else {
info.ModifyColumns = append(info.ModifyColumns, newCol.Name)
}
if pos != nil && pos.Tp == ast.ColumnPositionAfter {
info.PositionColumns = append(info.PositionColumns, pos.RelativeColumn.Name)
}
case model.ActionSetDefaultValue:
args := job.JobArgs.(*model.SetDefaultValueArgs)
col := args.Col
info.ModifyColumns = append(info.ModifyColumns, col.Name)
case model.ActionAlterIndexVisibility:
idxName := job.JobArgs.(*model.AlterIndexVisibilityArgs).IndexName
info.AlterIndexes = append(info.AlterIndexes, idxName)
case model.ActionRebaseAutoID, model.ActionModifyTableComment, model.ActionModifyTableCharsetAndCollate:
case model.ActionAddForeignKey:
fkInfo := job.JobArgs.(*model.AddForeignKeyArgs).FkInfo
info.AddForeignKeys = append(info.AddForeignKeys, model.AddForeignKeyInfo{
Name: fkInfo.Name,
Cols: fkInfo.Cols,
})
case model.ActionDropForeignKey:
// there is nothing to verify for `DROP FOREIGN KEY`
default:
return dbterror.ErrRunMultiSchemaChanges.FastGenByArgs(job.Type.String())
}
return nil
}
func checkOperateSameColAndIdx(info *model.MultiSchemaInfo) error {
modifyCols := make(map[string]struct{})
modifyIdx := make(map[string]struct{})
checkColumns := func(colNames []ast.CIStr, addToModifyCols bool) error {
for _, colName := range colNames {
name := colName.L
if _, ok := modifyCols[name]; ok {
return dbterror.ErrOperateSameColumn.GenWithStackByArgs(name)
}
if addToModifyCols {
modifyCols[name] = struct{}{}
}
}
return nil
}
checkIndexes := func(idxNames []ast.CIStr, addToModifyIdx bool) error {
for _, idxName := range idxNames {
name := idxName.L
if _, ok := modifyIdx[name]; ok {
return dbterror.ErrOperateSameIndex.GenWithStackByArgs(name)
}
if addToModifyIdx {
modifyIdx[name] = struct{}{}
}
}
return nil
}
if err := checkColumns(info.AddColumns, true); err != nil {
return err
}
if err := checkColumns(info.DropColumns, true); err != nil {
return err
}
if err := checkColumns(info.PositionColumns, false); err != nil {
return err
}
if err := checkColumns(info.ModifyColumns, true); err != nil {
return err
}
if err := checkColumns(info.RelativeColumns, false); err != nil {
return err
}
if err := checkIndexes(info.AddIndexes, true); err != nil {
return err
}
if err := checkIndexes(info.DropIndexes, true); err != nil {
return err
}
return checkIndexes(info.AlterIndexes, true)
}
func mergeAddIndex(info *model.MultiSchemaInfo) {
var mergedSubJob *model.SubJob
var mergeCnt int
for _, subJob := range info.SubJobs {
if subJob.Type == model.ActionAddForeignKey {
// Foreign key requires the order of adding indexes is unchanged.
return
}
if subJob.Type == model.ActionAddIndex {
mergeCnt++
if mergedSubJob == nil {
mergedSubJob = subJob.Clone()
mergedSubJob.RawArgs = nil
}
}
}
if mergeCnt <= 1 {
// No multiple add index jobs in this multi-schema change.
return
}
newSubJobs := make([]*model.SubJob, 0, len(info.SubJobs))
newAddIndexesArgs := &model.ModifyIndexArgs{OpType: model.OpAddIndex}
for _, subJob := range info.SubJobs {
if subJob.Type == model.ActionAddIndex {
args := subJob.JobArgs.(*model.ModifyIndexArgs)
newAddIndexesArgs.IndexArgs = append(newAddIndexesArgs.IndexArgs, args.IndexArgs...)
} else {
newSubJobs = append(newSubJobs, subJob)
}
}
// place the merged add index job at the end of the sub-jobs.
mergedSubJob.JobArgs = newAddIndexesArgs
newSubJobs = append(newSubJobs, mergedSubJob)
info.SubJobs = newSubJobs
}
func checkOperateDropIndexUseByForeignKey(info *model.MultiSchemaInfo, t table.Table) error {
var remainIndexes, droppingIndexes []*model.IndexInfo
tbInfo := t.Meta()
for _, idx := range tbInfo.Indices {
dropping := false
for _, name := range info.DropIndexes {
if name.L == idx.Name.L {
dropping = true
break
}
}
if dropping {
droppingIndexes = append(droppingIndexes, idx)
} else {
remainIndexes = append(remainIndexes, idx)
}
}
for _, fk := range info.AddForeignKeys {
if droppingIdx := model.FindIndexByColumns(tbInfo, droppingIndexes, fk.Cols...); droppingIdx != nil && model.FindIndexByColumns(tbInfo, remainIndexes, fk.Cols...) == nil {
return dbterror.ErrDropIndexNeededInForeignKey.GenWithStackByArgs(droppingIdx.Name)
}
}
return nil
}
func checkMultiSchemaInfo(info *model.MultiSchemaInfo, t table.Table) error {
err := checkOperateSameColAndIdx(info)
if err != nil {
return err
}
err = checkVisibleColumnCnt(t, len(info.AddColumns), len(info.DropColumns))
if err != nil {
return err
}
err = checkOperateDropIndexUseByForeignKey(info, t)
if err != nil {
return err
}
return checkAddColumnTooManyColumns(len(t.Cols()) + len(info.AddColumns) - len(info.DropColumns))
}
func appendMultiChangeWarningsToOwnerCtx(ctx sessionctx.Context, job *model.Job) {
if job.MultiSchemaInfo == nil || job.Type != model.ActionMultiSchemaChange {
return
}
for _, sub := range job.MultiSchemaInfo.SubJobs {
if sub.Warning != nil {
ctx.GetSessionVars().StmtCtx.AppendNote(sub.Warning)
}
}
}
// rollingBackMultiSchemaChange updates a multi-schema change job
// from cancelling state to rollingback state.
func rollingBackMultiSchemaChange(job *model.Job) error {
if !job.MultiSchemaInfo.Revertible {
// Cannot rolling back because the jobs are non-revertible.
// Resume the job state to running.
job.State = model.JobStateRunning
return nil
}
// Mark all the jobs to cancelling.
for _, sub := range job.MultiSchemaInfo.SubJobs {
switch sub.State {
case model.JobStateRunning:
sub.State = model.JobStateCancelling
case model.JobStateNone, model.JobStateQueueing:
sub.State = model.JobStateCancelled
}
}
job.State = model.JobStateRollingback
return dbterror.ErrCancelledDDLJob
}
func finishMultiSchemaJob(job *model.Job, t *meta.Mutator) (ver int64, err error) {
for _, sub := range job.MultiSchemaInfo.SubJobs {
if ver < sub.SchemaVer {
ver = sub.SchemaVer
}
}
tblInfo, err := t.GetTable(job.SchemaID, job.TableID)
if err != nil {
return 0, err
}
job.FinishTableJob(model.JobStateDone, model.StateNone, ver, tblInfo)
return 0, err
}