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517 lines
17 KiB
517 lines
17 KiB
// Copyright 2017 PingCAP, Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package util
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import (
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"context"
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"fmt"
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"math"
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"strconv"
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"sync"
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"sync/atomic"
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"time"
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"unsafe"
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"github.com/pingcap/errors"
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"github.com/pingcap/failpoint"
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"github.com/pingcap/parser/terror"
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"github.com/pingcap/tidb/metrics"
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"github.com/pingcap/tidb/owner"
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tidbutil "github.com/pingcap/tidb/util"
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"github.com/pingcap/tidb/util/logutil"
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"go.etcd.io/etcd/clientv3"
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"go.etcd.io/etcd/clientv3/concurrency"
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"go.etcd.io/etcd/etcdserver/api/v3rpc/rpctypes"
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"go.uber.org/zap"
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)
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const (
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// DDLAllSchemaVersions is the path on etcd that is used to store all servers current schema versions.
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// It's exported for testing.
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DDLAllSchemaVersions = "/tidb/ddl/all_schema_versions"
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// DDLGlobalSchemaVersion is the path on etcd that is used to store the latest schema versions.
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// It's exported for testing.
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DDLGlobalSchemaVersion = "/tidb/ddl/global_schema_version"
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// InitialVersion is the initial schema version for every server.
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// It's exported for testing.
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InitialVersion = "0"
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putKeyNoRetry = 1
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keyOpDefaultRetryCnt = 3
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putKeyRetryUnlimited = math.MaxInt64
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keyOpDefaultTimeout = 2 * time.Second
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keyOpRetryInterval = 30 * time.Millisecond
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checkVersInterval = 20 * time.Millisecond
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ddlPrompt = "ddl-syncer"
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)
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var (
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// CheckVersFirstWaitTime is a waitting time before the owner checks all the servers of the schema version,
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// and it's an exported variable for testing.
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CheckVersFirstWaitTime = 50 * time.Millisecond
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// SyncerSessionTTL is the etcd session's TTL in seconds.
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// and it's an exported variable for testing.
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SyncerSessionTTL = 90
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)
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// SchemaSyncer is used to synchronize schema version between the DDL worker leader and followers through etcd.
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type SchemaSyncer interface {
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// Init sets the global schema version path to etcd if it isn't exist,
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// then watch this path, and initializes the self schema version to etcd.
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Init(ctx context.Context) error
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// UpdateSelfVersion updates the current version to the self path on etcd.
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UpdateSelfVersion(ctx context.Context, version int64) error
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// RemoveSelfVersionPath remove the self path from etcd.
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RemoveSelfVersionPath() error
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// OwnerUpdateGlobalVersion updates the latest version to the global path on etcd until updating is successful or the ctx is done.
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OwnerUpdateGlobalVersion(ctx context.Context, version int64) error
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// GlobalVersionCh gets the chan for watching global version.
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GlobalVersionCh() clientv3.WatchChan
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// WatchGlobalSchemaVer watches the global schema version.
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WatchGlobalSchemaVer(ctx context.Context)
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// MustGetGlobalVersion gets the global version. The only reason it fails is that ctx is done.
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MustGetGlobalVersion(ctx context.Context) (int64, error)
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// Done returns a channel that closes when the syncer is no longer being refreshed.
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Done() <-chan struct{}
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// Restart restarts the syncer when it's on longer being refreshed.
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Restart(ctx context.Context) error
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// OwnerCheckAllVersions checks whether all followers' schema version are equal to
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// the latest schema version. If the result is false, wait for a while and check again util the processing time reach 2 * lease.
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// It returns until all servers' versions are equal to the latest version or the ctx is done.
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OwnerCheckAllVersions(ctx context.Context, latestVer int64) error
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// NotifyCleanExpiredPaths informs to clean up expired paths.
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// The returned value is used for testing.
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NotifyCleanExpiredPaths() bool
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// StartCleanWork starts to clean up tasks.
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StartCleanWork()
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// CloseCleanWork ends cleanup tasks.
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CloseCleanWork()
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}
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type ownerChecker interface {
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IsOwner() bool
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}
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type schemaVersionSyncer struct {
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selfSchemaVerPath string
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etcdCli *clientv3.Client
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session unsafe.Pointer
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mu struct {
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sync.RWMutex
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globalVerCh clientv3.WatchChan
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}
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// for clean worker
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ownerChecker ownerChecker
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notifyCleanExpiredPathsCh chan struct{}
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quiteCh chan struct{}
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}
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// NewSchemaSyncer creates a new SchemaSyncer.
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func NewSchemaSyncer(etcdCli *clientv3.Client, id string, oc ownerChecker) SchemaSyncer {
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return &schemaVersionSyncer{
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etcdCli: etcdCli,
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selfSchemaVerPath: fmt.Sprintf("%s/%s", DDLAllSchemaVersions, id),
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ownerChecker: oc,
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notifyCleanExpiredPathsCh: make(chan struct{}, 1),
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quiteCh: make(chan struct{}),
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}
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}
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// PutKVToEtcd puts key value to etcd.
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// etcdCli is client of etcd.
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// retryCnt is retry time when an error occurs.
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// opts is configures of etcd Operations.
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func PutKVToEtcd(ctx context.Context, etcdCli *clientv3.Client, retryCnt int, key, val string,
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opts ...clientv3.OpOption) error {
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var err error
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for i := 0; i < retryCnt; i++ {
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if isContextDone(ctx) {
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return errors.Trace(ctx.Err())
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}
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childCtx, cancel := context.WithTimeout(ctx, keyOpDefaultTimeout)
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_, err = etcdCli.Put(childCtx, key, val, opts...)
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cancel()
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if err == nil {
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return nil
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}
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logutil.BgLogger().Warn("[ddl] etcd-cli put kv failed", zap.String("key", key), zap.String("value", val), zap.Error(err), zap.Int("retryCnt", i))
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time.Sleep(keyOpRetryInterval)
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}
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return errors.Trace(err)
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}
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// Init implements SchemaSyncer.Init interface.
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func (s *schemaVersionSyncer) Init(ctx context.Context) error {
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startTime := time.Now()
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var err error
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defer func() {
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metrics.DeploySyncerHistogram.WithLabelValues(metrics.SyncerInit, metrics.RetLabel(err)).Observe(time.Since(startTime).Seconds())
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}()
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_, err = s.etcdCli.Txn(ctx).
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If(clientv3.Compare(clientv3.CreateRevision(DDLGlobalSchemaVersion), "=", 0)).
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Then(clientv3.OpPut(DDLGlobalSchemaVersion, InitialVersion)).
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Commit()
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if err != nil {
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return errors.Trace(err)
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}
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logPrefix := fmt.Sprintf("[%s] %s", ddlPrompt, s.selfSchemaVerPath)
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session, err := owner.NewSession(ctx, logPrefix, s.etcdCli, owner.NewSessionDefaultRetryCnt, SyncerSessionTTL)
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if err != nil {
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return errors.Trace(err)
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}
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s.storeSession(session)
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s.mu.Lock()
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s.mu.globalVerCh = s.etcdCli.Watch(ctx, DDLGlobalSchemaVersion)
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s.mu.Unlock()
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err = PutKVToEtcd(ctx, s.etcdCli, keyOpDefaultRetryCnt, s.selfSchemaVerPath, InitialVersion,
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clientv3.WithLease(s.loadSession().Lease()))
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return errors.Trace(err)
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}
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func (s *schemaVersionSyncer) loadSession() *concurrency.Session {
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return (*concurrency.Session)(atomic.LoadPointer(&s.session))
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}
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func (s *schemaVersionSyncer) storeSession(session *concurrency.Session) {
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atomic.StorePointer(&s.session, (unsafe.Pointer)(session))
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}
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// Done implements SchemaSyncer.Done interface.
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func (s *schemaVersionSyncer) Done() <-chan struct{} {
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failpoint.Inject("ErrorMockSessionDone", func(val failpoint.Value) {
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if val.(bool) {
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err := s.loadSession().Close()
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logutil.BgLogger().Error("close session failed", zap.Error(err))
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}
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})
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return s.loadSession().Done()
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}
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// Restart implements SchemaSyncer.Restart interface.
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func (s *schemaVersionSyncer) Restart(ctx context.Context) error {
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startTime := time.Now()
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var err error
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defer func() {
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metrics.DeploySyncerHistogram.WithLabelValues(metrics.SyncerRestart, metrics.RetLabel(err)).Observe(time.Since(startTime).Seconds())
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}()
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logPrefix := fmt.Sprintf("[%s] %s", ddlPrompt, s.selfSchemaVerPath)
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// NewSession's context will affect the exit of the session.
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session, err := owner.NewSession(ctx, logPrefix, s.etcdCli, owner.NewSessionRetryUnlimited, SyncerSessionTTL)
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if err != nil {
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return errors.Trace(err)
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}
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s.storeSession(session)
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childCtx, cancel := context.WithTimeout(ctx, keyOpDefaultTimeout)
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defer cancel()
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err = PutKVToEtcd(childCtx, s.etcdCli, putKeyRetryUnlimited, s.selfSchemaVerPath, InitialVersion,
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clientv3.WithLease(s.loadSession().Lease()))
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return errors.Trace(err)
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}
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// GlobalVersionCh implements SchemaSyncer.GlobalVersionCh interface.
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func (s *schemaVersionSyncer) GlobalVersionCh() clientv3.WatchChan {
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s.mu.RLock()
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defer s.mu.RUnlock()
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return s.mu.globalVerCh
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}
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// WatchGlobalSchemaVer implements SchemaSyncer.WatchGlobalSchemaVer interface.
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func (s *schemaVersionSyncer) WatchGlobalSchemaVer(ctx context.Context) {
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startTime := time.Now()
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// Make sure the globalVerCh doesn't receive the information of 'close' before we finish the rewatch.
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s.mu.Lock()
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s.mu.globalVerCh = nil
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s.mu.Unlock()
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go func() {
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defer func() {
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metrics.DeploySyncerHistogram.WithLabelValues(metrics.SyncerRewatch, metrics.RetLabel(nil)).Observe(time.Since(startTime).Seconds())
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}()
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ch := s.etcdCli.Watch(ctx, DDLGlobalSchemaVersion)
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s.mu.Lock()
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s.mu.globalVerCh = ch
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s.mu.Unlock()
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logutil.BgLogger().Info("[ddl] syncer watch global schema finished")
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}()
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}
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// UpdateSelfVersion implements SchemaSyncer.UpdateSelfVersion interface.
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func (s *schemaVersionSyncer) UpdateSelfVersion(ctx context.Context, version int64) error {
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startTime := time.Now()
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ver := strconv.FormatInt(version, 10)
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err := PutKVToEtcd(ctx, s.etcdCli, putKeyNoRetry, s.selfSchemaVerPath, ver,
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clientv3.WithLease(s.loadSession().Lease()))
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metrics.UpdateSelfVersionHistogram.WithLabelValues(metrics.RetLabel(err)).Observe(time.Since(startTime).Seconds())
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return errors.Trace(err)
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}
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// OwnerUpdateGlobalVersion implements SchemaSyncer.OwnerUpdateGlobalVersion interface.
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func (s *schemaVersionSyncer) OwnerUpdateGlobalVersion(ctx context.Context, version int64) error {
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startTime := time.Now()
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ver := strconv.FormatInt(version, 10)
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// TODO: If the version is larger than the original global version, we need set the version.
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// Otherwise, we'd better set the original global version.
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err := PutKVToEtcd(ctx, s.etcdCli, putKeyRetryUnlimited, DDLGlobalSchemaVersion, ver)
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metrics.OwnerHandleSyncerHistogram.WithLabelValues(metrics.OwnerUpdateGlobalVersion, metrics.RetLabel(err)).Observe(time.Since(startTime).Seconds())
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return errors.Trace(err)
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}
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// RemoveSelfVersionPath implements SchemaSyncer.RemoveSelfVersionPath interface.
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func (s *schemaVersionSyncer) RemoveSelfVersionPath() error {
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startTime := time.Now()
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var err error
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defer func() {
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metrics.DeploySyncerHistogram.WithLabelValues(metrics.SyncerClear, metrics.RetLabel(err)).Observe(time.Since(startTime).Seconds())
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}()
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err = DeleteKeyFromEtcd(s.selfSchemaVerPath, s.etcdCli, keyOpDefaultRetryCnt, keyOpDefaultTimeout)
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return errors.Trace(err)
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}
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// DeleteKeyFromEtcd deletes key value from etcd.
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func DeleteKeyFromEtcd(key string, etcdCli *clientv3.Client, retryCnt int, timeout time.Duration) error {
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var err error
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ctx := context.Background()
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for i := 0; i < retryCnt; i++ {
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childCtx, cancel := context.WithTimeout(ctx, timeout)
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_, err = etcdCli.Delete(childCtx, key)
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cancel()
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if err == nil {
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return nil
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}
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logutil.BgLogger().Warn("[ddl] etcd-cli delete key failed", zap.String("key", key), zap.Error(err), zap.Int("retryCnt", i))
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}
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return errors.Trace(err)
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}
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// MustGetGlobalVersion implements SchemaSyncer.MustGetGlobalVersion interface.
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func (s *schemaVersionSyncer) MustGetGlobalVersion(ctx context.Context) (int64, error) {
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startTime := time.Now()
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var (
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err error
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ver int
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resp *clientv3.GetResponse
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)
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failedCnt := 0
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intervalCnt := int(time.Second / keyOpRetryInterval)
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defer func() {
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metrics.OwnerHandleSyncerHistogram.WithLabelValues(metrics.OwnerGetGlobalVersion, metrics.RetLabel(err)).Observe(time.Since(startTime).Seconds())
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}()
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for {
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if err != nil {
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if failedCnt%intervalCnt == 0 {
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logutil.BgLogger().Info("[ddl] syncer get global version failed", zap.Error(err))
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}
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time.Sleep(keyOpRetryInterval)
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failedCnt++
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}
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if isContextDone(ctx) {
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err = errors.Trace(ctx.Err())
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return 0, err
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}
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resp, err = s.etcdCli.Get(ctx, DDLGlobalSchemaVersion)
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if err != nil {
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continue
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}
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if len(resp.Kvs) > 0 {
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ver, err = strconv.Atoi(string(resp.Kvs[0].Value))
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if err == nil {
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return int64(ver), nil
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}
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}
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}
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}
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func isContextDone(ctx context.Context) bool {
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select {
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case <-ctx.Done():
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return true
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default:
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}
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return false
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}
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// OwnerCheckAllVersions implements SchemaSyncer.OwnerCheckAllVersions interface.
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func (s *schemaVersionSyncer) OwnerCheckAllVersions(ctx context.Context, latestVer int64) error {
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startTime := time.Now()
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time.Sleep(CheckVersFirstWaitTime)
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notMatchVerCnt := 0
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intervalCnt := int(time.Second / checkVersInterval)
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updatedMap := make(map[string]struct{})
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var err error
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defer func() {
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metrics.OwnerHandleSyncerHistogram.WithLabelValues(metrics.OwnerCheckAllVersions, metrics.RetLabel(err)).Observe(time.Since(startTime).Seconds())
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}()
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for {
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if isContextDone(ctx) {
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// ctx is canceled or timeout.
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err = errors.Trace(ctx.Err())
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return err
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}
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resp, err := s.etcdCli.Get(ctx, DDLAllSchemaVersions, clientv3.WithPrefix())
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if err != nil {
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logutil.BgLogger().Info("[ddl] syncer check all versions failed, continue checking.", zap.Error(err))
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continue
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}
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succ := true
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for _, kv := range resp.Kvs {
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if _, ok := updatedMap[string(kv.Key)]; ok {
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continue
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}
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ver, err := strconv.Atoi(string(kv.Value))
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if err != nil {
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logutil.BgLogger().Info("[ddl] syncer check all versions, convert value to int failed, continue checking.", zap.String("ddl", string(kv.Key)), zap.String("value", string(kv.Value)), zap.Error(err))
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succ = false
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break
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}
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if int64(ver) < latestVer {
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if notMatchVerCnt%intervalCnt == 0 {
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logutil.BgLogger().Info("[ddl] syncer check all versions, someone is not synced, continue checking",
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zap.String("ddl", string(kv.Key)), zap.Int("currentVer", ver), zap.Int64("latestVer", latestVer))
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}
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succ = false
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notMatchVerCnt++
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break
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}
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updatedMap[string(kv.Key)] = struct{}{}
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}
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if succ {
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return nil
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}
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time.Sleep(checkVersInterval)
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}
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}
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const (
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opDefaultRetryCnt = 10
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failedGetTTLLimit = 20
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opDefaultTimeout = 3 * time.Second
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opRetryInterval = 500 * time.Millisecond
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)
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// NeededCleanTTL is exported for testing.
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var NeededCleanTTL = int64(-60)
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func (s *schemaVersionSyncer) StartCleanWork() {
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defer tidbutil.Recover(metrics.LabelDDLSyncer, "StartCleanWorker", nil, false)
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for {
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select {
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case <-s.notifyCleanExpiredPathsCh:
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if !s.ownerChecker.IsOwner() {
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continue
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}
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for i := 0; i < opDefaultRetryCnt; i++ {
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childCtx, cancelFunc := context.WithTimeout(context.Background(), opDefaultTimeout)
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resp, err := s.etcdCli.Leases(childCtx)
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cancelFunc()
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if err != nil {
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logutil.BgLogger().Info("[ddl] syncer clean expired paths, failed to get leases.", zap.Error(err))
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continue
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}
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if isFinished := s.doCleanExpirePaths(resp.Leases); isFinished {
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break
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}
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time.Sleep(opRetryInterval)
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}
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case <-s.quiteCh:
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return
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}
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}
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}
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func (s *schemaVersionSyncer) CloseCleanWork() {
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close(s.quiteCh)
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}
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func (s *schemaVersionSyncer) NotifyCleanExpiredPaths() bool {
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var isNotified bool
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var err error
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startTime := time.Now()
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select {
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case s.notifyCleanExpiredPathsCh <- struct{}{}:
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isNotified = true
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default:
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err = errors.New("channel is full, failed to notify clean expired paths")
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}
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metrics.OwnerHandleSyncerHistogram.WithLabelValues(metrics.OwnerNotifyCleanExpirePaths, metrics.RetLabel(err)).Observe(time.Since(startTime).Seconds())
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return isNotified
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}
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func (s *schemaVersionSyncer) doCleanExpirePaths(leases []clientv3.LeaseStatus) bool {
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failedGetIDs := 0
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failedRevokeIDs := 0
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startTime := time.Now()
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defer func() {
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metrics.OwnerHandleSyncerHistogram.WithLabelValues(metrics.OwnerCleanExpirePaths, metrics.RetLabel(nil)).Observe(time.Since(startTime).Seconds())
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}()
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// TODO: Now LeaseStatus only has lease ID.
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for _, lease := range leases {
|
|
// The DDL owner key uses '%x', so here print it too.
|
|
leaseID := fmt.Sprintf("%x, %d", lease.ID, lease.ID)
|
|
childCtx, cancelFunc := context.WithTimeout(context.Background(), opDefaultTimeout)
|
|
ttlResp, err := s.etcdCli.TimeToLive(childCtx, lease.ID)
|
|
cancelFunc()
|
|
if err != nil {
|
|
logutil.BgLogger().Info("[ddl] syncer clean expired paths, failed to get one TTL.", zap.String("leaseID", leaseID), zap.Error(err))
|
|
failedGetIDs++
|
|
continue
|
|
}
|
|
|
|
if failedGetIDs > failedGetTTLLimit {
|
|
return false
|
|
}
|
|
if ttlResp.TTL >= NeededCleanTTL {
|
|
continue
|
|
}
|
|
|
|
st := time.Now()
|
|
childCtx, cancelFunc = context.WithTimeout(context.Background(), opDefaultTimeout)
|
|
_, err = s.etcdCli.Revoke(childCtx, lease.ID)
|
|
cancelFunc()
|
|
if err != nil && terror.ErrorEqual(err, rpctypes.ErrLeaseNotFound) {
|
|
logutil.BgLogger().Warn("[ddl] syncer clean expired paths, failed to revoke lease.", zap.String("leaseID", leaseID),
|
|
zap.Int64("TTL", ttlResp.TTL), zap.Error(err))
|
|
failedRevokeIDs++
|
|
}
|
|
logutil.BgLogger().Warn("[ddl] syncer clean expired paths,", zap.String("leaseID", leaseID), zap.Int64("TTL", ttlResp.TTL))
|
|
metrics.OwnerHandleSyncerHistogram.WithLabelValues(metrics.OwnerCleanOneExpirePath, metrics.RetLabel(err)).Observe(time.Since(st).Seconds())
|
|
}
|
|
|
|
if failedGetIDs == 0 && failedRevokeIDs == 0 {
|
|
return true
|
|
}
|
|
return false
|
|
}
|
|
|