forked from tikv/client-go
/
txn_committer.go
596 lines (545 loc) · 17.8 KB
/
txn_committer.go
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// Copyright 2016 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 store
import (
"bytes"
"context"
"math"
"sync"
"sync/atomic"
"time"
"github.com/journeymidnight/client-go/config"
"github.com/journeymidnight/client-go/metrics"
"github.com/journeymidnight/client-go/retry"
"github.com/journeymidnight/client-go/rpc"
"github.com/journeymidnight/client-go/txnkv/kv"
pb "github.com/pingcap/kvproto/pkg/kvrpcpb"
"github.com/pkg/errors"
log "github.com/sirupsen/logrus"
)
type commitAction int
const (
actionPrewrite commitAction = 1
actionCommit commitAction = 2
actionCleanup commitAction = 3
)
func (ca commitAction) String() string {
switch ca {
case actionPrewrite:
return "prewrite"
case actionCommit:
return "commit"
case actionCleanup:
return "cleanup"
}
return "unknown"
}
// MetricsTag returns detail tag for metrics.
func (ca commitAction) MetricsTag() string {
return "2pc_" + ca.String()
}
// TxnCommitter executes a two-phase commit protocol.
type TxnCommitter struct {
Priority pb.CommandPri
SyncLog bool
ConnID uint64 // ConnID is used for log.
store *TiKVStore
conf *config.Config
startTS uint64
keys [][]byte
mutations map[string]*pb.Mutation
lockTTL uint64
commitTS uint64
mu struct {
sync.RWMutex
committed bool
undeterminedErr error // undeterminedErr saves the rpc error we encounter when commit primary key.
}
cleanWg sync.WaitGroup
// maxTxnTimeUse represents max time a Txn may use (in ms) from its startTS to commitTS.
// We use it to guarantee GC worker will not influence any active txn. The value
// should be less than GC life time.
maxTxnTimeUse uint64
detail CommitDetails
}
// NewTxnCommitter creates a TxnCommitter.
func NewTxnCommitter(store *TiKVStore, startTS uint64, startTime time.Time, mutations map[string]*pb.Mutation) (*TxnCommitter, error) {
var (
keys [][]byte
size int
putCnt int
delCnt int
lockCnt int
)
conf := store.GetConfig()
for key, mut := range mutations {
switch mut.Op {
case pb.Op_Put, pb.Op_Insert:
putCnt++
case pb.Op_Del:
delCnt++
case pb.Op_Lock:
lockCnt++
}
keys = append(keys, []byte(key))
entrySize := len(mut.Key) + len(mut.Value)
if entrySize > conf.Txn.EntrySizeLimit {
return nil, kv.ErrEntryTooLarge
}
size += entrySize
}
if putCnt == 0 && delCnt == 0 {
return nil, nil
}
if len(keys) > int(conf.Txn.EntryCountLimit) || size > conf.Txn.TotalSizeLimit {
return nil, kv.ErrTxnTooLarge
}
// Convert from sec to ms
maxTxnTimeUse := uint64(conf.Txn.MaxTimeUse) * 1000
metrics.TxnWriteKVCountHistogram.Observe(float64(len(keys)))
metrics.TxnWriteSizeHistogram.Observe(float64(size))
return &TxnCommitter{
store: store,
conf: conf,
startTS: startTS,
keys: keys,
mutations: mutations,
lockTTL: txnLockTTL(conf, startTime, size),
maxTxnTimeUse: maxTxnTimeUse,
detail: CommitDetails{WriteSize: size, WriteKeys: len(keys)},
}, nil
}
func (c *TxnCommitter) primary() []byte {
return c.keys[0]
}
const bytesPerMiB = 1024 * 1024
func txnLockTTL(conf *config.Config, startTime time.Time, txnSize int) uint64 {
// Increase lockTTL for large transactions.
// The formula is `ttl = ttlFactor * sqrt(sizeInMiB)`.
// When writeSize is less than 256KB, the base ttl is defaultTTL (3s);
// When writeSize is 1MiB, 100MiB, or 400MiB, ttl is 6s, 60s, 120s correspondingly;
lockTTL := conf.Txn.DefaultLockTTL
if txnSize >= conf.Txn.CommitBatchSize {
sizeMiB := float64(txnSize) / bytesPerMiB
lockTTL = uint64(float64(conf.Txn.TTLFactor) * math.Sqrt(sizeMiB))
if lockTTL < conf.Txn.DefaultLockTTL {
lockTTL = conf.Txn.DefaultLockTTL
}
if lockTTL > conf.Txn.MaxLockTTL {
lockTTL = conf.Txn.MaxLockTTL
}
}
// Increase lockTTL by the transaction's read time.
// When resolving a lock, we compare current ts and startTS+lockTTL to decide whether to clean up. If a txn
// takes a long time to read, increasing its TTL will help to prevent it from been aborted soon after prewrite.
elapsed := time.Since(startTime) / time.Millisecond
return lockTTL + uint64(elapsed)
}
// doActionOnKeys groups keys into primary batch and secondary batches, if primary batch exists in the key,
// it does action on primary batch first, then on secondary batches. If action is commit, secondary batches
// is done in background goroutine.
func (c *TxnCommitter) doActionOnKeys(bo *retry.Backoffer, action commitAction, keys [][]byte) error {
if len(keys) == 0 {
return nil
}
groups, firstRegion, err := c.store.GetRegionCache().GroupKeysByRegion(bo, keys)
if err != nil {
return err
}
metrics.TxnRegionsNumHistogram.WithLabelValues(action.MetricsTag()).Observe(float64(len(groups)))
var batches []batchKeys
var sizeFunc = c.keySize
if action == actionPrewrite {
sizeFunc = c.keyValueSize
atomic.AddInt32(&c.detail.PrewriteRegionNum, int32(len(groups)))
}
// Make sure the group that contains primary key goes first.
commitBatchSize := c.conf.Txn.CommitBatchSize
batches = appendBatchBySize(batches, firstRegion, groups[firstRegion], sizeFunc, commitBatchSize)
delete(groups, firstRegion)
for id, g := range groups {
batches = appendBatchBySize(batches, id, g, sizeFunc, commitBatchSize)
}
firstIsPrimary := bytes.Equal(keys[0], c.primary())
if firstIsPrimary && (action == actionCommit || action == actionCleanup) {
// primary should be committed/cleanup first
err = c.doActionOnBatches(bo, action, batches[:1])
if err != nil {
return err
}
batches = batches[1:]
}
if action == actionCommit {
// Commit secondary batches in background goroutine to reduce latency.
// The backoffer instance is created outside of the goroutine to avoid
// potencial data race in unit test since `CommitMaxBackoff` will be updated
// by test suites.
secondaryBo := retry.NewBackoffer(context.Background(), retry.CommitMaxBackoff)
go func() {
e := c.doActionOnBatches(secondaryBo, action, batches)
if e != nil {
log.Debugf("con:%d 2PC async doActionOnBatches %s err: %v", c.ConnID, action, e)
metrics.SecondaryLockCleanupFailureCounter.WithLabelValues("commit").Inc()
}
}()
} else {
err = c.doActionOnBatches(bo, action, batches)
}
return err
}
// doActionOnBatches does action to batches in parallel.
func (c *TxnCommitter) doActionOnBatches(bo *retry.Backoffer, action commitAction, batches []batchKeys) error {
if len(batches) == 0 {
return nil
}
var singleBatchActionFunc func(bo *retry.Backoffer, batch batchKeys) error
switch action {
case actionPrewrite:
singleBatchActionFunc = c.prewriteSingleBatch
case actionCommit:
singleBatchActionFunc = c.commitSingleBatch
case actionCleanup:
singleBatchActionFunc = c.cleanupSingleBatch
}
if len(batches) == 1 {
e := singleBatchActionFunc(bo, batches[0])
if e != nil {
log.Debugf("con:%d 2PC doActionOnBatches %s failed: %v, tid: %d", c.ConnID, action, e, c.startTS)
}
return e
}
// For prewrite, stop sending other requests after receiving first error.
backoffer := bo
var cancel context.CancelFunc
if action == actionPrewrite {
backoffer, cancel = bo.Fork()
defer cancel()
}
// Concurrently do the work for each batch.
ch := make(chan error, len(batches))
for _, batch1 := range batches {
batch := batch1
go func() {
if action == actionCommit {
// Because the secondary batches of the commit actions are implemented to be
// committed asynchronously in background goroutines, we should not
// fork a child context and call cancel() while the foreground goroutine exits.
// Otherwise the background goroutines will be canceled exceptionally.
// Here we makes a new clone of the original backoffer for this goroutine
// exclusively to avoid the data race when using the same backoffer
// in concurrent goroutines.
singleBatchBackoffer := backoffer.Clone()
ch <- singleBatchActionFunc(singleBatchBackoffer, batch)
} else {
singleBatchBackoffer, singleBatchCancel := backoffer.Fork()
defer singleBatchCancel()
ch <- singleBatchActionFunc(singleBatchBackoffer, batch)
}
}()
}
var err error
for i := 0; i < len(batches); i++ {
if e := <-ch; e != nil {
log.Debugf("con:%d 2PC doActionOnBatches %s failed: %v, tid: %d", c.ConnID, action, e, c.startTS)
// Cancel other requests and return the first error.
if cancel != nil {
log.Debugf("con:%d 2PC doActionOnBatches %s to cancel other actions, tid: %d", c.ConnID, action, c.startTS)
cancel()
}
if err == nil {
err = e
}
}
}
return err
}
func (c *TxnCommitter) keyValueSize(key []byte) int {
size := len(key)
if mutation := c.mutations[string(key)]; mutation != nil {
size += len(mutation.Value)
}
return size
}
func (c *TxnCommitter) keySize(key []byte) int {
return len(key)
}
func (c *TxnCommitter) prewriteSingleBatch(bo *retry.Backoffer, batch batchKeys) error {
mutations := make([]*pb.Mutation, len(batch.keys))
for i, k := range batch.keys {
mutations[i] = c.mutations[string(k)]
}
req := &rpc.Request{
Type: rpc.CmdPrewrite,
Prewrite: &pb.PrewriteRequest{
Mutations: mutations,
PrimaryLock: c.primary(),
StartVersion: c.startTS,
LockTtl: c.lockTTL,
},
Context: pb.Context{
Priority: c.Priority,
SyncLog: c.SyncLog,
},
}
for {
resp, err := c.store.SendReq(bo, req, batch.region, c.conf.RPC.ReadTimeoutShort)
if err != nil {
return err
}
regionErr, err := resp.GetRegionError()
if err != nil {
return err
}
if regionErr != nil {
err = bo.Backoff(retry.BoRegionMiss, errors.New(regionErr.String()))
if err != nil {
return err
}
return c.prewriteKeys(bo, batch.keys)
}
prewriteResp := resp.Prewrite
if prewriteResp == nil {
return errors.WithStack(rpc.ErrBodyMissing)
}
keyErrs := prewriteResp.GetErrors()
if len(keyErrs) == 0 {
return nil
}
var locks []*Lock
for _, keyErr := range keyErrs {
// Check already exists error
if alreadyExist := keyErr.GetAlreadyExist(); alreadyExist != nil {
return errors.WithStack(ErrKeyAlreadyExist(alreadyExist.GetKey()))
}
// Extract lock from key error
lock, err1 := extractLockFromKeyErr(keyErr, c.conf.Txn.DefaultLockTTL)
if err1 != nil {
return err1
}
log.Debugf("con:%d 2PC prewrite encounters lock: %v", c.ConnID, lock)
locks = append(locks, lock)
}
start := time.Now()
ok, err := c.store.GetLockResolver().ResolveLocks(bo, locks)
if err != nil {
return err
}
atomic.AddInt64(&c.detail.ResolveLockTime, int64(time.Since(start)))
if !ok {
err = bo.Backoff(retry.BoTxnLock, errors.Errorf("2PC prewrite lockedKeys: %d", len(locks)))
if err != nil {
return err
}
}
}
}
func (c *TxnCommitter) setUndeterminedErr(err error) {
c.mu.Lock()
defer c.mu.Unlock()
c.mu.undeterminedErr = err
}
func (c *TxnCommitter) getUndeterminedErr() error {
c.mu.RLock()
defer c.mu.RUnlock()
return c.mu.undeterminedErr
}
func (c *TxnCommitter) commitSingleBatch(bo *retry.Backoffer, batch batchKeys) error {
req := &rpc.Request{
Type: rpc.CmdCommit,
Commit: &pb.CommitRequest{
StartVersion: c.startTS,
Keys: batch.keys,
CommitVersion: c.commitTS,
},
Context: pb.Context{
Priority: c.Priority,
SyncLog: c.SyncLog,
},
}
req.Context.Priority = c.Priority
sender := rpc.NewRegionRequestSender(c.store.GetRegionCache(), c.store.GetRPCClient())
resp, err := sender.SendReq(bo, req, batch.region, c.conf.RPC.ReadTimeoutShort)
// If we fail to receive response for the request that commits primary key, it will be undetermined whether this
// transaction has been successfully committed.
// Under this circumstance, we can not declare the commit is complete (may lead to data lost), nor can we throw
// an error (may lead to the duplicated key error when upper level restarts the transaction). Currently the best
// solution is to populate this error and let upper layer drop the connection to the corresponding mysql client.
isPrimary := bytes.Equal(batch.keys[0], c.primary())
if isPrimary && sender.RPCError() != nil {
c.setUndeterminedErr(sender.RPCError())
}
if err != nil {
return err
}
regionErr, err := resp.GetRegionError()
if err != nil {
return err
}
if regionErr != nil {
err = bo.Backoff(retry.BoRegionMiss, errors.New(regionErr.String()))
if err != nil {
return err
}
// re-split keys and commit again.
return c.commitKeys(bo, batch.keys)
}
commitResp := resp.Commit
if commitResp == nil {
return errors.WithStack(rpc.ErrBodyMissing)
}
// Here we can make sure tikv has processed the commit primary key request. So
// we can clean undetermined error.
if isPrimary {
c.setUndeterminedErr(nil)
}
if keyErr := commitResp.GetError(); keyErr != nil {
c.mu.RLock()
defer c.mu.RUnlock()
err = errors.Errorf("con:%d 2PC commit failed: %v", c.ConnID, keyErr.String())
if c.mu.committed {
// No secondary key could be rolled back after it's primary key is committed.
// There must be a serious bug somewhere.
log.Errorf("2PC failed commit key after primary key committed: %v, tid: %d", err, c.startTS)
return err
}
// The transaction maybe rolled back by concurrent transactions.
log.Debugf("2PC failed commit primary key: %v, retry later, tid: %d", err, c.startTS)
return errors.WithMessage(err, TxnRetryableMark)
}
c.mu.Lock()
defer c.mu.Unlock()
// Group that contains primary key is always the first.
// We mark transaction's status committed when we receive the first success response.
c.mu.committed = true
return nil
}
func (c *TxnCommitter) cleanupSingleBatch(bo *retry.Backoffer, batch batchKeys) error {
req := &rpc.Request{
Type: rpc.CmdBatchRollback,
BatchRollback: &pb.BatchRollbackRequest{
Keys: batch.keys,
StartVersion: c.startTS,
},
Context: pb.Context{
Priority: c.Priority,
SyncLog: c.SyncLog,
},
}
resp, err := c.store.SendReq(bo, req, batch.region, c.conf.RPC.ReadTimeoutShort)
if err != nil {
return err
}
regionErr, err := resp.GetRegionError()
if err != nil {
return err
}
if regionErr != nil {
err = bo.Backoff(retry.BoRegionMiss, errors.New(regionErr.String()))
if err != nil {
return err
}
return c.cleanupKeys(bo, batch.keys)
}
if keyErr := resp.BatchRollback.GetError(); keyErr != nil {
err = errors.Errorf("con:%d 2PC cleanup failed: %s", c.ConnID, keyErr)
log.Debugf("2PC failed cleanup key: %v, tid: %d", err, c.startTS)
return err
}
return nil
}
func (c *TxnCommitter) prewriteKeys(bo *retry.Backoffer, keys [][]byte) error {
return c.doActionOnKeys(bo, actionPrewrite, keys)
}
func (c *TxnCommitter) commitKeys(bo *retry.Backoffer, keys [][]byte) error {
return c.doActionOnKeys(bo, actionCommit, keys)
}
func (c *TxnCommitter) cleanupKeys(bo *retry.Backoffer, keys [][]byte) error {
return c.doActionOnKeys(bo, actionCleanup, keys)
}
// Execute executes the two-phase commit protocol.
func (c *TxnCommitter) Execute(ctx context.Context) error {
defer func() {
// Always clean up all written keys if the txn does not commit.
c.mu.RLock()
committed := c.mu.committed
undetermined := c.mu.undeterminedErr != nil
c.mu.RUnlock()
if !committed && !undetermined {
c.cleanWg.Add(1)
go func() {
err := c.cleanupKeys(retry.NewBackoffer(context.Background(), retry.CleanupMaxBackoff), c.keys)
if err != nil {
metrics.SecondaryLockCleanupFailureCounter.WithLabelValues("rollback").Inc()
log.Infof("con:%d 2PC cleanup err: %v, tid: %d", c.ConnID, err, c.startTS)
} else {
log.Infof("con:%d 2PC clean up done, tid: %d", c.ConnID, c.startTS)
}
c.cleanWg.Done()
}()
}
}()
prewriteBo := retry.NewBackoffer(ctx, retry.PrewriteMaxBackoff)
start := time.Now()
err := c.prewriteKeys(prewriteBo, c.keys)
c.detail.PrewriteTime = time.Since(start)
c.detail.TotalBackoffTime += prewriteBo.TotalSleep()
if err != nil {
log.Debugf("con:%d 2PC failed on prewrite: %v, tid: %d", c.ConnID, err, c.startTS)
return err
}
start = time.Now()
commitTS, err := c.store.GetTimestampWithRetry(retry.NewBackoffer(ctx, retry.TsoMaxBackoff))
if err != nil {
log.Warnf("con:%d 2PC get commitTS failed: %v, tid: %d", c.ConnID, err, c.startTS)
return err
}
c.detail.GetCommitTsTime = time.Since(start)
// check commitTS
if commitTS <= c.startTS {
err = errors.Errorf("con:%d Invalid transaction tso with start_ts=%v while commit_ts=%v",
c.ConnID, c.startTS, commitTS)
log.Error(err)
return err
}
c.commitTS = commitTS
if c.store.GetOracle().IsExpired(c.startTS, c.maxTxnTimeUse) {
err = errors.Errorf("con:%d txn takes too much time, start: %d, commit: %d", c.ConnID, c.startTS, c.commitTS)
return errors.WithMessage(err, TxnRetryableMark)
}
start = time.Now()
commitBo := retry.NewBackoffer(ctx, retry.CommitMaxBackoff)
err = c.commitKeys(commitBo, c.keys)
c.detail.CommitTime = time.Since(start)
c.detail.TotalBackoffTime += commitBo.TotalSleep()
if err != nil {
if undeterminedErr := c.getUndeterminedErr(); undeterminedErr != nil {
log.Warnf("con:%d 2PC commit result undetermined, err: %v, rpcErr: %v, tid: %v", c.ConnID, err, undeterminedErr, c.startTS)
log.Error(err)
err = errors.WithStack(ErrResultUndetermined)
}
if !c.mu.committed {
log.Debugf("con:%d 2PC failed on commit: %v, tid: %d", c.ConnID, err, c.startTS)
return err
}
log.Debugf("con:%d 2PC succeed with error: %v, tid: %d", c.ConnID, err, c.startTS)
}
return nil
}
// GetKeys returns all keys of the committer.
func (c *TxnCommitter) GetKeys() [][]byte {
return c.keys
}
// GetCommitTS returns the commit timestamp of the transaction.
func (c *TxnCommitter) GetCommitTS() uint64 {
return c.commitTS
}