mirror of https://github.com/tikv/client-go.git
122 lines
3.6 KiB
Go
122 lines
3.6 KiB
Go
// Copyright 2021 TiKV Authors
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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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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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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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// NOTE: The code in this file is based on code from the
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// TiDB project, licensed under the Apache License v 2.0
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//
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// https://github.com/pingcap/tidb/tree/cc5e161ac06827589c4966674597c137cc9e809c/store/tikv/kv/kv.go
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//
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package kv
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import (
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"math"
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"sync"
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"time"
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"github.com/pingcap/kvproto/pkg/kvrpcpb"
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tikverr "github.com/tikv/client-go/v2/error"
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"github.com/tikv/client-go/v2/util"
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)
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// ReturnedValue pairs the Value and AlreadyLocked flag for PessimisticLock return values result.
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type ReturnedValue struct {
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Value []byte
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AlreadyLocked bool
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}
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// Used for pessimistic lock wait time
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// these two constants are special for lock protocol with tikv
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// math.MaxInt64 means always wait, 0 means nowait, others meaning lock wait in milliseconds
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const (
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LockAlwaysWait = int64(math.MaxInt64)
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LockNoWait = int64(0)
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)
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type lockWaitTimeInMs struct {
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value int64
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}
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func defaultLockWaitTime() *lockWaitTimeInMs {
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return &lockWaitTimeInMs{value: LockAlwaysWait}
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}
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// LockCtx contains information for LockKeys method.
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type LockCtx struct {
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Killed *uint32
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ForUpdateTS uint64
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lockWaitTime *lockWaitTimeInMs
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WaitStartTime time.Time
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PessimisticLockWaited *int32
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LockKeysDuration *int64
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LockKeysCount *int32
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ReturnValues bool
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Values map[string]ReturnedValue
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ValuesLock sync.Mutex
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LockExpired *uint32
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Stats *util.LockKeysDetails
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ResourceGroupTag []byte
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// ResourceGroupTagger is a special tagger used only for PessimisticLockRequest.
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// We did not use tikvrpc.ResourceGroupTagger here because the kv package is a
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// more basic component, and we cannot rely on tikvrpc.Request here, so we treat
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// LockCtx specially.
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ResourceGroupTagger func(*kvrpcpb.PessimisticLockRequest) []byte
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OnDeadlock func(*tikverr.ErrDeadlock)
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}
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// LockWaitTime returns lockWaitTimeInMs
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func (ctx *LockCtx) LockWaitTime() int64 {
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if ctx.lockWaitTime == nil {
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ctx.lockWaitTime = defaultLockWaitTime()
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}
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return ctx.lockWaitTime.value
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}
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// NewLockCtx creates a LockCtx.
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func NewLockCtx(forUpdateTS uint64, lockWaitTime int64, waitStartTime time.Time) *LockCtx {
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return &LockCtx{
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ForUpdateTS: forUpdateTS,
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lockWaitTime: &lockWaitTimeInMs{value: lockWaitTime},
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WaitStartTime: waitStartTime,
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}
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}
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// InitReturnValues creates the map to store returned value.
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func (ctx *LockCtx) InitReturnValues(valueLen int) {
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ctx.ReturnValues = true
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ctx.Values = make(map[string]ReturnedValue, valueLen)
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}
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// GetValueNotLocked returns a value if the key is not already locked.
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// (nil, false) means already locked.
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func (ctx *LockCtx) GetValueNotLocked(key []byte) ([]byte, bool) {
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rv := ctx.Values[string(key)]
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if !rv.AlreadyLocked {
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return rv.Value, true
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}
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return nil, false
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}
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// IterateValuesNotLocked applies f to all key-values that are not already
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// locked.
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func (ctx *LockCtx) IterateValuesNotLocked(f func([]byte, []byte)) {
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ctx.ValuesLock.Lock()
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defer ctx.ValuesLock.Unlock()
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for key, val := range ctx.Values {
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if !val.AlreadyLocked {
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f([]byte(key), val.Value)
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}
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}
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}
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