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