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gitea/vendor/github.com/pingcap/tidb/kv/txn.go

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2.1 KiB
Go

// 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 kv
import (
"math"
"math/rand"
"time"
"github.com/juju/errors"
"github.com/ngaut/log"
)
// RunInNewTxn will run the f in a new transaction environment.
func RunInNewTxn(store Storage, retryable bool, f func(txn Transaction) error) error {
for i := 0; i < maxRetryCnt; i++ {
txn, err := store.Begin()
if err != nil {
log.Errorf("[kv] RunInNewTxn error - %v", err)
return errors.Trace(err)
}
err = f(txn)
if retryable && IsRetryableError(err) {
log.Warnf("[kv] Retry txn %v", txn)
txn.Rollback()
continue
}
if err != nil {
txn.Rollback()
return errors.Trace(err)
}
err = txn.Commit()
if retryable && IsRetryableError(err) {
log.Warnf("[kv] Retry txn %v", txn)
txn.Rollback()
BackOff(i)
continue
}
if err != nil {
return errors.Trace(err)
}
break
}
return nil
}
var (
// Max retry count in RunInNewTxn
maxRetryCnt = 100
// retryBackOffBase is the initial duration, in microsecond, a failed transaction stays dormancy before it retries
retryBackOffBase = 1
// retryBackOffCap is the max amount of duration, in microsecond, a failed transaction stays dormancy before it retries
retryBackOffCap = 100
)
// BackOff Implements exponential backoff with full jitter.
// Returns real back off time in microsecond.
// See: http://www.awsarchitectureblog.com/2015/03/backoff.html.
func BackOff(attempts int) int {
upper := int(math.Min(float64(retryBackOffCap), float64(retryBackOffBase)*math.Pow(2.0, float64(attempts))))
sleep := time.Duration(rand.Intn(upper)) * time.Millisecond
time.Sleep(sleep)
return int(sleep)
}