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gitea/vendor/github.com/pingcap/tidb/ddl/reorg.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,
// See the License for the specific language governing permissions and
// limitations under the License.
package ddl
import (
"fmt"
"time"
"github.com/juju/errors"
"github.com/pingcap/tidb/context"
"github.com/pingcap/tidb/kv"
"github.com/pingcap/tidb/meta"
"github.com/pingcap/tidb/model"
"github.com/pingcap/tidb/terror"
)
var _ context.Context = &reorgContext{}
// reorgContext implements context.Context interface for reorganization use.
type reorgContext struct {
store kv.Storage
m map[fmt.Stringer]interface{}
txn kv.Transaction
}
func (c *reorgContext) GetTxn(forceNew bool) (kv.Transaction, error) {
if forceNew {
if c.txn != nil {
if err := c.txn.Commit(); err != nil {
return nil, errors.Trace(err)
}
c.txn = nil
}
}
if c.txn != nil {
return c.txn, nil
}
txn, err := c.store.Begin()
if err != nil {
return nil, errors.Trace(err)
}
c.txn = txn
return c.txn, nil
}
func (c *reorgContext) FinishTxn(rollback bool) error {
if c.txn == nil {
return nil
}
var err error
if rollback {
err = c.txn.Rollback()
} else {
err = c.txn.Commit()
}
c.txn = nil
return errors.Trace(err)
}
func (c *reorgContext) SetValue(key fmt.Stringer, value interface{}) {
c.m[key] = value
}
func (c *reorgContext) Value(key fmt.Stringer) interface{} {
return c.m[key]
}
func (c *reorgContext) ClearValue(key fmt.Stringer) {
delete(c.m, key)
}
func (d *ddl) newReorgContext() context.Context {
c := &reorgContext{
store: d.store,
m: make(map[fmt.Stringer]interface{}),
}
return c
}
const waitReorgTimeout = 10 * time.Second
var errWaitReorgTimeout = errors.New("wait for reorganization timeout")
func (d *ddl) runReorgJob(f func() error) error {
if d.reorgDoneCh == nil {
// start a reorganization job
d.wait.Add(1)
d.reorgDoneCh = make(chan error, 1)
go func() {
defer d.wait.Done()
d.reorgDoneCh <- f()
}()
}
waitTimeout := waitReorgTimeout
// if d.lease is 0, we are using a local storage,
// and we can wait the reorganization to be done here.
// if d.lease > 0, we don't need to wait here because
// we will wait 2 * lease outer and try checking again,
// so we use a very little timeout here.
if d.lease > 0 {
waitTimeout = 1 * time.Millisecond
}
// wait reorganization job done or timeout
select {
case err := <-d.reorgDoneCh:
d.reorgDoneCh = nil
return errors.Trace(err)
case <-d.quitCh:
// we return errWaitReorgTimeout here too, so that outer loop will break.
return errWaitReorgTimeout
case <-time.After(waitTimeout):
// if timeout, we will return, check the owner and retry to wait job done again.
return errWaitReorgTimeout
}
}
func (d *ddl) isReorgRunnable(txn kv.Transaction) error {
if d.isClosed() {
// worker is closed, can't run reorganization.
return errors.Trace(ErrWorkerClosed)
}
t := meta.NewMeta(txn)
owner, err := t.GetDDLJobOwner()
if err != nil {
return errors.Trace(err)
} else if owner == nil || owner.OwnerID != d.uuid {
// if no owner, we will try later, so here just return error.
// or another server is owner, return error too.
return errors.Trace(ErrNotOwner)
}
return nil
}
func (d *ddl) delKeysWithPrefix(prefix kv.Key) error {
for {
keys := make([]kv.Key, 0, maxBatchSize)
err := kv.RunInNewTxn(d.store, true, func(txn kv.Transaction) error {
if err1 := d.isReorgRunnable(txn); err1 != nil {
return errors.Trace(err1)
}
iter, err := txn.Seek(prefix)
if err != nil {
return errors.Trace(err)
}
defer iter.Close()
for i := 0; i < maxBatchSize; i++ {
if iter.Valid() && iter.Key().HasPrefix(prefix) {
keys = append(keys, iter.Key().Clone())
err = iter.Next()
if err != nil {
return errors.Trace(err)
}
} else {
break
}
}
for _, key := range keys {
err := txn.Delete(key)
// must skip ErrNotExist
// if key doesn't exist, skip this error.
if err != nil && !terror.ErrorEqual(err, kv.ErrNotExist) {
return errors.Trace(err)
}
}
return nil
})
if err != nil {
return errors.Trace(err)
}
// delete no keys, return.
if len(keys) == 0 {
return nil
}
}
}
type reorgInfo struct {
*model.Job
Handle int64
d *ddl
first bool
}
func (d *ddl) getReorgInfo(t *meta.Meta, job *model.Job) (*reorgInfo, error) {
var err error
info := &reorgInfo{
Job: job,
d: d,
first: job.SnapshotVer == 0,
}
if info.first {
// get the current version for reorganization if we don't have
var ver kv.Version
ver, err = d.store.CurrentVersion()
if err != nil {
return nil, errors.Trace(err)
} else if ver.Ver <= 0 {
return nil, errors.Errorf("invalid storage current version %d", ver.Ver)
}
job.SnapshotVer = ver.Ver
} else {
info.Handle, err = t.GetDDLReorgHandle(job)
if err != nil {
return nil, errors.Trace(err)
}
}
if info.Handle > 0 {
// we have already handled this handle, so use next
info.Handle++
}
return info, errors.Trace(err)
}
func (r *reorgInfo) UpdateHandle(txn kv.Transaction, handle int64) error {
t := meta.NewMeta(txn)
return errors.Trace(t.UpdateDDLReorgHandle(r.Job, handle))
}