tidb serializable 源码
tidb serializable 代码
文件路径：/sessiontxn/isolation/serializable.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 isolation
import (
"github.com/pingcap/tidb/kv"
"github.com/pingcap/tidb/parser/ast"
"github.com/pingcap/tidb/sessionctx"
"github.com/pingcap/tidb/sessionctx/variable"
"github.com/pingcap/tidb/sessiontxn"
)
// PessimisticSerializableTxnContextProvider provides txn context for isolation level oracle-like serializable
type PessimisticSerializableTxnContextProvider struct {
baseTxnContextProvider
}
// NewPessimisticSerializableTxnContextProvider returns a new PessimisticSerializableTxnContextProvider
func NewPessimisticSerializableTxnContextProvider(sctx sessionctx.Context,
causalConsistencyOnly bool) *PessimisticSerializableTxnContextProvider {
provider := &PessimisticSerializableTxnContextProvider{
baseTxnContextProvider{
sctx: sctx,
causalConsistencyOnly: causalConsistencyOnly,
onInitializeTxnCtx: func(txnCtx *variable.TransactionContext) {
txnCtx.IsPessimistic = true
txnCtx.Isolation = ast.Serializable
},
onTxnActiveFunc: func(txn kv.Transaction, _ sessiontxn.EnterNewTxnType) {
txn.SetOption(kv.Pessimistic, true)
},
},
}
provider.getStmtForUpdateTSFunc = provider.getTxnStartTS
provider.getStmtReadTSFunc = provider.getTxnStartTS
return provider
}
// OnStmtErrorForNextAction is the hook that should be called when a new statement get an error
func (p *PessimisticSerializableTxnContextProvider) OnStmtErrorForNextAction(
point sessiontxn.StmtErrorHandlePoint, err error) (sessiontxn.StmtErrorAction, error) {
switch point {
case sessiontxn.StmtErrAfterPessimisticLock:
// In oracle-like serializable isolation, we do not retry encountering pessimistic lock error.
return sessiontxn.ErrorAction(err)
default:
return sessiontxn.NoIdea()
}
}
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