Files
tidb/session/txnmanager.go

137 lines
3.8 KiB
Go

// Copyright 2021 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 session
import (
"context"
"github.com/pingcap/errors"
"github.com/pingcap/tidb/executor"
"github.com/pingcap/tidb/infoschema"
"github.com/pingcap/tidb/parser/ast"
"github.com/pingcap/tidb/sessionctx"
"github.com/pingcap/tidb/sessiontxn"
"github.com/pingcap/tidb/sessiontxn/legacy"
"github.com/pingcap/tidb/sessiontxn/staleread"
)
func init() {
sessiontxn.GetTxnManager = getTxnManager
}
func getTxnManager(sctx sessionctx.Context) sessiontxn.TxnManager {
if manager, ok := sctx.GetSessionVars().TxnManager.(sessiontxn.TxnManager); ok {
return manager
}
manager := newTxnManager(sctx)
sctx.GetSessionVars().TxnManager = manager
return manager
}
// txnManager implements sessiontxn.TxnManager
type txnManager struct {
sctx sessionctx.Context
ctxProvider sessiontxn.TxnContextProvider
}
func newTxnManager(sctx sessionctx.Context) *txnManager {
return &txnManager{sctx: sctx}
}
func (m *txnManager) GetTxnInfoSchema() infoschema.InfoSchema {
if m.ctxProvider == nil {
return nil
}
return m.ctxProvider.GetTxnInfoSchema()
}
func (m *txnManager) GetStmtReadTS() (uint64, error) {
if m.ctxProvider == nil {
return 0, errors.New("context provider not set")
}
return m.ctxProvider.GetStmtReadTS()
}
func (m *txnManager) GetStmtForUpdateTS() (uint64, error) {
if m.ctxProvider == nil {
return 0, errors.New("context provider not set")
}
return m.ctxProvider.GetStmtForUpdateTS()
}
func (m *txnManager) GetContextProvider() sessiontxn.TxnContextProvider {
return m.ctxProvider
}
func (m *txnManager) EnterNewTxn(ctx context.Context, r *sessiontxn.EnterNewTxnRequest) error {
m.ctxProvider = m.newProviderWithRequest(r)
if err := m.ctxProvider.OnInitialize(ctx, r.Type); err != nil {
return err
}
if r.Type == sessiontxn.EnterNewTxnWithBeginStmt {
m.sctx.GetSessionVars().SetInTxn(true)
}
return nil
}
// OnStmtStart is the hook that should be called when a new statement started
func (m *txnManager) OnStmtStart(ctx context.Context) error {
if m.ctxProvider == nil {
return errors.New("context provider not set")
}
return m.ctxProvider.OnStmtStart(ctx)
}
// OnStmtErrorForNextAction is the hook that should be called when a new statement get an error
func (m *txnManager) OnStmtErrorForNextAction(point sessiontxn.StmtErrorHandlePoint, err error) (sessiontxn.StmtErrorAction, error) {
if m.ctxProvider == nil {
return sessiontxn.NoIdea()
}
return m.ctxProvider.OnStmtErrorForNextAction(point, err)
}
// OnStmtRetry is the hook that should be called when a statement retry
func (m *txnManager) OnStmtRetry(ctx context.Context) error {
if m.ctxProvider == nil {
return errors.New("context provider not set")
}
return m.ctxProvider.OnStmtRetry(ctx)
}
func (m *txnManager) newProviderWithRequest(r *sessiontxn.EnterNewTxnRequest) sessiontxn.TxnContextProvider {
if r.Provider != nil {
return r.Provider
}
txnMode := r.TxnMode
if txnMode == "" {
txnMode = m.sctx.GetSessionVars().TxnMode
}
if r.StaleReadTS > 0 {
return staleread.NewStalenessTxnContextProvider(m.sctx, r.StaleReadTS, nil)
}
return &legacy.SimpleTxnContextProvider{
Sctx: m.sctx,
Pessimistic: txnMode == ast.Pessimistic,
CausalConsistencyOnly: r.CausalConsistencyOnly,
UpdateForUpdateTS: executor.UpdateForUpdateTS,
}
}