k3s/vendor/go.etcd.io/etcd/mvcc/backend/batch_tx.go
Darren Shepherd f4ff2bf3a8 Update vendor
2020-06-06 22:38:12 -07:00

340 lines
8.2 KiB
Go

// Copyright 2015 The etcd Authors
//
// 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 backend
import (
"bytes"
"math"
"sync"
"sync/atomic"
"time"
bolt "go.etcd.io/bbolt"
"go.uber.org/zap"
)
type BatchTx interface {
ReadTx
UnsafeCreateBucket(name []byte)
UnsafePut(bucketName []byte, key []byte, value []byte)
UnsafeSeqPut(bucketName []byte, key []byte, value []byte)
UnsafeDelete(bucketName []byte, key []byte)
// Commit commits a previous tx and begins a new writable one.
Commit()
// CommitAndStop commits the previous tx and does not create a new one.
CommitAndStop()
}
type batchTx struct {
sync.Mutex
tx *bolt.Tx
backend *backend
pending int
}
func (t *batchTx) Lock() {
t.Mutex.Lock()
}
func (t *batchTx) Unlock() {
if t.pending >= t.backend.batchLimit {
t.commit(false)
}
t.Mutex.Unlock()
}
// BatchTx interface embeds ReadTx interface. But RLock() and RUnlock() do not
// have appropriate semantics in BatchTx interface. Therefore should not be called.
// TODO: might want to decouple ReadTx and BatchTx
func (t *batchTx) RLock() {
panic("unexpected RLock")
}
func (t *batchTx) RUnlock() {
panic("unexpected RUnlock")
}
func (t *batchTx) UnsafeCreateBucket(name []byte) {
_, err := t.tx.CreateBucket(name)
if err != nil && err != bolt.ErrBucketExists {
if t.backend.lg != nil {
t.backend.lg.Fatal(
"failed to create a bucket",
zap.String("bucket-name", string(name)),
zap.Error(err),
)
} else {
plog.Fatalf("cannot create bucket %s (%v)", name, err)
}
}
t.pending++
}
// UnsafePut must be called holding the lock on the tx.
func (t *batchTx) UnsafePut(bucketName []byte, key []byte, value []byte) {
t.unsafePut(bucketName, key, value, false)
}
// UnsafeSeqPut must be called holding the lock on the tx.
func (t *batchTx) UnsafeSeqPut(bucketName []byte, key []byte, value []byte) {
t.unsafePut(bucketName, key, value, true)
}
func (t *batchTx) unsafePut(bucketName []byte, key []byte, value []byte, seq bool) {
bucket := t.tx.Bucket(bucketName)
if bucket == nil {
if t.backend.lg != nil {
t.backend.lg.Fatal(
"failed to find a bucket",
zap.String("bucket-name", string(bucketName)),
)
} else {
plog.Fatalf("bucket %s does not exist", bucketName)
}
}
if seq {
// it is useful to increase fill percent when the workloads are mostly append-only.
// this can delay the page split and reduce space usage.
bucket.FillPercent = 0.9
}
if err := bucket.Put(key, value); err != nil {
if t.backend.lg != nil {
t.backend.lg.Fatal(
"failed to write to a bucket",
zap.String("bucket-name", string(bucketName)),
zap.Error(err),
)
} else {
plog.Fatalf("cannot put key into bucket (%v)", err)
}
}
t.pending++
}
// UnsafeRange must be called holding the lock on the tx.
func (t *batchTx) UnsafeRange(bucketName, key, endKey []byte, limit int64) ([][]byte, [][]byte) {
bucket := t.tx.Bucket(bucketName)
if bucket == nil {
if t.backend.lg != nil {
t.backend.lg.Fatal(
"failed to find a bucket",
zap.String("bucket-name", string(bucketName)),
)
} else {
plog.Fatalf("bucket %s does not exist", bucketName)
}
}
return unsafeRange(bucket.Cursor(), key, endKey, limit)
}
func unsafeRange(c *bolt.Cursor, key, endKey []byte, limit int64) (keys [][]byte, vs [][]byte) {
if limit <= 0 {
limit = math.MaxInt64
}
var isMatch func(b []byte) bool
if len(endKey) > 0 {
isMatch = func(b []byte) bool { return bytes.Compare(b, endKey) < 0 }
} else {
isMatch = func(b []byte) bool { return bytes.Equal(b, key) }
limit = 1
}
for ck, cv := c.Seek(key); ck != nil && isMatch(ck); ck, cv = c.Next() {
vs = append(vs, cv)
keys = append(keys, ck)
if limit == int64(len(keys)) {
break
}
}
return keys, vs
}
// UnsafeDelete must be called holding the lock on the tx.
func (t *batchTx) UnsafeDelete(bucketName []byte, key []byte) {
bucket := t.tx.Bucket(bucketName)
if bucket == nil {
if t.backend.lg != nil {
t.backend.lg.Fatal(
"failed to find a bucket",
zap.String("bucket-name", string(bucketName)),
)
} else {
plog.Fatalf("bucket %s does not exist", bucketName)
}
}
err := bucket.Delete(key)
if err != nil {
if t.backend.lg != nil {
t.backend.lg.Fatal(
"failed to delete a key",
zap.String("bucket-name", string(bucketName)),
zap.Error(err),
)
} else {
plog.Fatalf("cannot delete key from bucket (%v)", err)
}
}
t.pending++
}
// UnsafeForEach must be called holding the lock on the tx.
func (t *batchTx) UnsafeForEach(bucketName []byte, visitor func(k, v []byte) error) error {
return unsafeForEach(t.tx, bucketName, visitor)
}
func unsafeForEach(tx *bolt.Tx, bucket []byte, visitor func(k, v []byte) error) error {
if b := tx.Bucket(bucket); b != nil {
return b.ForEach(visitor)
}
return nil
}
// Commit commits a previous tx and begins a new writable one.
func (t *batchTx) Commit() {
t.Lock()
t.commit(false)
t.Unlock()
}
// CommitAndStop commits the previous tx and does not create a new one.
func (t *batchTx) CommitAndStop() {
t.Lock()
t.commit(true)
t.Unlock()
}
func (t *batchTx) safePending() int {
t.Mutex.Lock()
defer t.Mutex.Unlock()
return t.pending
}
func (t *batchTx) commit(stop bool) {
// commit the last tx
if t.tx != nil {
if t.pending == 0 && !stop {
return
}
start := time.Now()
// gofail: var beforeCommit struct{}
err := t.tx.Commit()
// gofail: var afterCommit struct{}
rebalanceSec.Observe(t.tx.Stats().RebalanceTime.Seconds())
spillSec.Observe(t.tx.Stats().SpillTime.Seconds())
writeSec.Observe(t.tx.Stats().WriteTime.Seconds())
commitSec.Observe(time.Since(start).Seconds())
atomic.AddInt64(&t.backend.commits, 1)
t.pending = 0
if err != nil {
if t.backend.lg != nil {
t.backend.lg.Fatal("failed to commit tx", zap.Error(err))
} else {
plog.Fatalf("cannot commit tx (%s)", err)
}
}
}
if !stop {
t.tx = t.backend.begin(true)
}
}
type batchTxBuffered struct {
batchTx
buf txWriteBuffer
}
func newBatchTxBuffered(backend *backend) *batchTxBuffered {
tx := &batchTxBuffered{
batchTx: batchTx{backend: backend},
buf: txWriteBuffer{
txBuffer: txBuffer{make(map[string]*bucketBuffer)},
seq: true,
},
}
tx.Commit()
return tx
}
func (t *batchTxBuffered) Unlock() {
if t.pending != 0 {
t.backend.readTx.Lock() // blocks txReadBuffer for writing.
t.buf.writeback(&t.backend.readTx.buf)
t.backend.readTx.Unlock()
if t.pending >= t.backend.batchLimit {
t.commit(false)
}
}
t.batchTx.Unlock()
}
func (t *batchTxBuffered) Commit() {
t.Lock()
t.commit(false)
t.Unlock()
}
func (t *batchTxBuffered) CommitAndStop() {
t.Lock()
t.commit(true)
t.Unlock()
}
func (t *batchTxBuffered) commit(stop bool) {
// all read txs must be closed to acquire boltdb commit rwlock
t.backend.readTx.Lock()
t.unsafeCommit(stop)
t.backend.readTx.Unlock()
}
func (t *batchTxBuffered) unsafeCommit(stop bool) {
if t.backend.readTx.tx != nil {
// wait all store read transactions using the current boltdb tx to finish,
// then close the boltdb tx
go func(tx *bolt.Tx, wg *sync.WaitGroup) {
wg.Wait()
if err := tx.Rollback(); err != nil {
if t.backend.lg != nil {
t.backend.lg.Fatal("failed to rollback tx", zap.Error(err))
} else {
plog.Fatalf("cannot rollback tx (%s)", err)
}
}
}(t.backend.readTx.tx, t.backend.readTx.txWg)
t.backend.readTx.reset()
}
t.batchTx.commit(stop)
if !stop {
t.backend.readTx.tx = t.backend.begin(false)
}
}
func (t *batchTxBuffered) UnsafePut(bucketName []byte, key []byte, value []byte) {
t.batchTx.UnsafePut(bucketName, key, value)
t.buf.put(bucketName, key, value)
}
func (t *batchTxBuffered) UnsafeSeqPut(bucketName []byte, key []byte, value []byte) {
t.batchTx.UnsafeSeqPut(bucketName, key, value)
t.buf.putSeq(bucketName, key, value)
}