855 lines
17 KiB
Go
855 lines
17 KiB
Go
// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
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// All rights reserved.
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//
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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package leveldb
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import (
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"sync"
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"time"
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"github.com/syndtr/goleveldb/leveldb/errors"
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"github.com/syndtr/goleveldb/leveldb/opt"
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"github.com/syndtr/goleveldb/leveldb/storage"
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)
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var (
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errCompactionTransactExiting = errors.New("leveldb: compaction transact exiting")
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)
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type cStat struct {
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duration time.Duration
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read int64
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write int64
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}
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func (p *cStat) add(n *cStatStaging) {
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p.duration += n.duration
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p.read += n.read
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p.write += n.write
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}
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func (p *cStat) get() (duration time.Duration, read, write int64) {
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return p.duration, p.read, p.write
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}
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type cStatStaging struct {
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start time.Time
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duration time.Duration
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on bool
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read int64
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write int64
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}
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func (p *cStatStaging) startTimer() {
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if !p.on {
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p.start = time.Now()
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p.on = true
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}
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}
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func (p *cStatStaging) stopTimer() {
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if p.on {
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p.duration += time.Since(p.start)
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p.on = false
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}
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}
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type cStats struct {
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lk sync.Mutex
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stats []cStat
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}
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func (p *cStats) addStat(level int, n *cStatStaging) {
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p.lk.Lock()
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if level >= len(p.stats) {
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newStats := make([]cStat, level+1)
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copy(newStats, p.stats)
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p.stats = newStats
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}
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p.stats[level].add(n)
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p.lk.Unlock()
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}
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func (p *cStats) getStat(level int) (duration time.Duration, read, write int64) {
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p.lk.Lock()
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defer p.lk.Unlock()
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if level < len(p.stats) {
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return p.stats[level].get()
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}
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return
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}
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func (db *DB) compactionError() {
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var err error
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noerr:
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// No error.
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for {
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select {
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case err = <-db.compErrSetC:
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switch {
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case err == nil:
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case err == ErrReadOnly, errors.IsCorrupted(err):
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goto hasperr
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default:
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goto haserr
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}
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case <-db.closeC:
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return
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}
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}
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haserr:
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// Transient error.
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for {
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select {
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case db.compErrC <- err:
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case err = <-db.compErrSetC:
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switch {
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case err == nil:
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goto noerr
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case err == ErrReadOnly, errors.IsCorrupted(err):
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goto hasperr
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default:
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}
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case <-db.closeC:
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return
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}
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}
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hasperr:
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// Persistent error.
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for {
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select {
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case db.compErrC <- err:
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case db.compPerErrC <- err:
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case db.writeLockC <- struct{}{}:
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// Hold write lock, so that write won't pass-through.
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db.compWriteLocking = true
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case <-db.closeC:
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if db.compWriteLocking {
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// We should release the lock or Close will hang.
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<-db.writeLockC
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}
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return
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}
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}
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}
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type compactionTransactCounter int
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func (cnt *compactionTransactCounter) incr() {
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*cnt++
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}
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type compactionTransactInterface interface {
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run(cnt *compactionTransactCounter) error
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revert() error
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}
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func (db *DB) compactionTransact(name string, t compactionTransactInterface) {
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defer func() {
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if x := recover(); x != nil {
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if x == errCompactionTransactExiting {
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if err := t.revert(); err != nil {
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db.logf("%s revert error %q", name, err)
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}
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}
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panic(x)
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}
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}()
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const (
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backoffMin = 1 * time.Second
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backoffMax = 8 * time.Second
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backoffMul = 2 * time.Second
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)
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var (
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backoff = backoffMin
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backoffT = time.NewTimer(backoff)
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lastCnt = compactionTransactCounter(0)
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disableBackoff = db.s.o.GetDisableCompactionBackoff()
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)
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for n := 0; ; n++ {
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// Check whether the DB is closed.
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if db.isClosed() {
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db.logf("%s exiting", name)
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db.compactionExitTransact()
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} else if n > 0 {
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db.logf("%s retrying N·%d", name, n)
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}
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// Execute.
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cnt := compactionTransactCounter(0)
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err := t.run(&cnt)
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if err != nil {
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db.logf("%s error I·%d %q", name, cnt, err)
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}
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// Set compaction error status.
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select {
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case db.compErrSetC <- err:
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case perr := <-db.compPerErrC:
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if err != nil {
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db.logf("%s exiting (persistent error %q)", name, perr)
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db.compactionExitTransact()
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}
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case <-db.closeC:
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db.logf("%s exiting", name)
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db.compactionExitTransact()
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}
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if err == nil {
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return
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}
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if errors.IsCorrupted(err) {
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db.logf("%s exiting (corruption detected)", name)
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db.compactionExitTransact()
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}
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if !disableBackoff {
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// Reset backoff duration if counter is advancing.
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if cnt > lastCnt {
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backoff = backoffMin
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lastCnt = cnt
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}
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// Backoff.
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backoffT.Reset(backoff)
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if backoff < backoffMax {
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backoff *= backoffMul
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if backoff > backoffMax {
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backoff = backoffMax
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}
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}
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select {
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case <-backoffT.C:
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case <-db.closeC:
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db.logf("%s exiting", name)
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db.compactionExitTransact()
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}
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}
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}
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}
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type compactionTransactFunc struct {
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runFunc func(cnt *compactionTransactCounter) error
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revertFunc func() error
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}
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func (t *compactionTransactFunc) run(cnt *compactionTransactCounter) error {
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return t.runFunc(cnt)
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}
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func (t *compactionTransactFunc) revert() error {
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if t.revertFunc != nil {
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return t.revertFunc()
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}
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return nil
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}
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func (db *DB) compactionTransactFunc(name string, run func(cnt *compactionTransactCounter) error, revert func() error) {
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db.compactionTransact(name, &compactionTransactFunc{run, revert})
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}
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func (db *DB) compactionExitTransact() {
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panic(errCompactionTransactExiting)
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}
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func (db *DB) compactionCommit(name string, rec *sessionRecord) {
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db.compCommitLk.Lock()
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defer db.compCommitLk.Unlock() // Defer is necessary.
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db.compactionTransactFunc(name+"@commit", func(cnt *compactionTransactCounter) error {
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return db.s.commit(rec)
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}, nil)
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}
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func (db *DB) memCompaction() {
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mdb := db.getFrozenMem()
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if mdb == nil {
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return
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}
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defer mdb.decref()
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db.logf("memdb@flush N·%d S·%s", mdb.Len(), shortenb(mdb.Size()))
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// Don't compact empty memdb.
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if mdb.Len() == 0 {
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db.logf("memdb@flush skipping")
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// drop frozen memdb
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db.dropFrozenMem()
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return
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}
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// Pause table compaction.
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resumeC := make(chan struct{})
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select {
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case db.tcompPauseC <- (chan<- struct{})(resumeC):
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case <-db.compPerErrC:
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close(resumeC)
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resumeC = nil
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case <-db.closeC:
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db.compactionExitTransact()
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}
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var (
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rec = &sessionRecord{}
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stats = &cStatStaging{}
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flushLevel int
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)
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// Generate tables.
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db.compactionTransactFunc("memdb@flush", func(cnt *compactionTransactCounter) (err error) {
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stats.startTimer()
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flushLevel, err = db.s.flushMemdb(rec, mdb.DB, db.memdbMaxLevel)
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stats.stopTimer()
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return
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}, func() error {
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for _, r := range rec.addedTables {
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db.logf("memdb@flush revert @%d", r.num)
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if err := db.s.stor.Remove(storage.FileDesc{Type: storage.TypeTable, Num: r.num}); err != nil {
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return err
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}
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}
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return nil
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})
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rec.setJournalNum(db.journalFd.Num)
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rec.setSeqNum(db.frozenSeq)
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// Commit.
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stats.startTimer()
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db.compactionCommit("memdb", rec)
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stats.stopTimer()
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db.logf("memdb@flush committed F·%d T·%v", len(rec.addedTables), stats.duration)
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for _, r := range rec.addedTables {
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stats.write += r.size
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}
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db.compStats.addStat(flushLevel, stats)
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// Drop frozen memdb.
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db.dropFrozenMem()
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// Resume table compaction.
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if resumeC != nil {
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select {
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case <-resumeC:
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close(resumeC)
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case <-db.closeC:
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db.compactionExitTransact()
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}
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}
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// Trigger table compaction.
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db.compTrigger(db.tcompCmdC)
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}
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type tableCompactionBuilder struct {
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db *DB
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s *session
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c *compaction
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rec *sessionRecord
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stat0, stat1 *cStatStaging
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snapHasLastUkey bool
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snapLastUkey []byte
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snapLastSeq uint64
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snapIter int
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snapKerrCnt int
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snapDropCnt int
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kerrCnt int
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dropCnt int
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minSeq uint64
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strict bool
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tableSize int
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tw *tWriter
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}
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func (b *tableCompactionBuilder) appendKV(key, value []byte) error {
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// Create new table if not already.
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if b.tw == nil {
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// Check for pause event.
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if b.db != nil {
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select {
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case ch := <-b.db.tcompPauseC:
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b.db.pauseCompaction(ch)
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case <-b.db.closeC:
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b.db.compactionExitTransact()
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default:
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}
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}
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// Create new table.
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var err error
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b.tw, err = b.s.tops.create()
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if err != nil {
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return err
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}
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}
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// Write key/value into table.
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return b.tw.append(key, value)
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}
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func (b *tableCompactionBuilder) needFlush() bool {
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return b.tw.tw.BytesLen() >= b.tableSize
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}
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func (b *tableCompactionBuilder) flush() error {
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t, err := b.tw.finish()
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if err != nil {
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return err
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}
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b.rec.addTableFile(b.c.sourceLevel+1, t)
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b.stat1.write += t.size
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b.s.logf("table@build created L%d@%d N·%d S·%s %q:%q", b.c.sourceLevel+1, t.fd.Num, b.tw.tw.EntriesLen(), shortenb(int(t.size)), t.imin, t.imax)
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b.tw = nil
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return nil
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}
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func (b *tableCompactionBuilder) cleanup() {
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if b.tw != nil {
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b.tw.drop()
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b.tw = nil
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}
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}
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func (b *tableCompactionBuilder) run(cnt *compactionTransactCounter) error {
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snapResumed := b.snapIter > 0
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hasLastUkey := b.snapHasLastUkey // The key might has zero length, so this is necessary.
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lastUkey := append([]byte{}, b.snapLastUkey...)
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lastSeq := b.snapLastSeq
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b.kerrCnt = b.snapKerrCnt
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b.dropCnt = b.snapDropCnt
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// Restore compaction state.
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b.c.restore()
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defer b.cleanup()
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b.stat1.startTimer()
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defer b.stat1.stopTimer()
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iter := b.c.newIterator()
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defer iter.Release()
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for i := 0; iter.Next(); i++ {
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// Incr transact counter.
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cnt.incr()
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// Skip until last state.
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if i < b.snapIter {
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continue
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}
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resumed := false
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if snapResumed {
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resumed = true
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snapResumed = false
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}
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ikey := iter.Key()
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ukey, seq, kt, kerr := parseInternalKey(ikey)
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if kerr == nil {
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shouldStop := !resumed && b.c.shouldStopBefore(ikey)
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if !hasLastUkey || b.s.icmp.uCompare(lastUkey, ukey) != 0 {
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// First occurrence of this user key.
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// Only rotate tables if ukey doesn't hop across.
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if b.tw != nil && (shouldStop || b.needFlush()) {
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if err := b.flush(); err != nil {
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return err
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}
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// Creates snapshot of the state.
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b.c.save()
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b.snapHasLastUkey = hasLastUkey
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b.snapLastUkey = append(b.snapLastUkey[:0], lastUkey...)
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b.snapLastSeq = lastSeq
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b.snapIter = i
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b.snapKerrCnt = b.kerrCnt
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b.snapDropCnt = b.dropCnt
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}
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hasLastUkey = true
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lastUkey = append(lastUkey[:0], ukey...)
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lastSeq = keyMaxSeq
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}
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switch {
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case lastSeq <= b.minSeq:
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// Dropped because newer entry for same user key exist
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fallthrough // (A)
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case kt == keyTypeDel && seq <= b.minSeq && b.c.baseLevelForKey(lastUkey):
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// For this user key:
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// (1) there is no data in higher levels
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// (2) data in lower levels will have larger seq numbers
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// (3) data in layers that are being compacted here and have
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// smaller seq numbers will be dropped in the next
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// few iterations of this loop (by rule (A) above).
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// Therefore this deletion marker is obsolete and can be dropped.
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lastSeq = seq
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b.dropCnt++
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continue
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default:
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lastSeq = seq
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}
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} else {
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if b.strict {
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return kerr
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}
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// Don't drop corrupted keys.
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hasLastUkey = false
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lastUkey = lastUkey[:0]
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lastSeq = keyMaxSeq
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b.kerrCnt++
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}
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if err := b.appendKV(ikey, iter.Value()); err != nil {
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return err
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}
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}
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if err := iter.Error(); err != nil {
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return err
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}
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// Finish last table.
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if b.tw != nil && !b.tw.empty() {
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return b.flush()
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}
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return nil
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}
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func (b *tableCompactionBuilder) revert() error {
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for _, at := range b.rec.addedTables {
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b.s.logf("table@build revert @%d", at.num)
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if err := b.s.stor.Remove(storage.FileDesc{Type: storage.TypeTable, Num: at.num}); err != nil {
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return err
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}
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}
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return nil
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}
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|
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func (db *DB) tableCompaction(c *compaction, noTrivial bool) {
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defer c.release()
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rec := &sessionRecord{}
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rec.addCompPtr(c.sourceLevel, c.imax)
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if !noTrivial && c.trivial() {
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t := c.levels[0][0]
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db.logf("table@move L%d@%d -> L%d", c.sourceLevel, t.fd.Num, c.sourceLevel+1)
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rec.delTable(c.sourceLevel, t.fd.Num)
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rec.addTableFile(c.sourceLevel+1, t)
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db.compactionCommit("table-move", rec)
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return
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}
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|
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var stats [2]cStatStaging
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for i, tables := range c.levels {
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for _, t := range tables {
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stats[i].read += t.size
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// Insert deleted tables into record
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rec.delTable(c.sourceLevel+i, t.fd.Num)
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}
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}
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sourceSize := int(stats[0].read + stats[1].read)
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minSeq := db.minSeq()
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db.logf("table@compaction L%d·%d -> L%d·%d S·%s Q·%d", c.sourceLevel, len(c.levels[0]), c.sourceLevel+1, len(c.levels[1]), shortenb(sourceSize), minSeq)
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b := &tableCompactionBuilder{
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db: db,
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s: db.s,
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c: c,
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rec: rec,
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stat1: &stats[1],
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minSeq: minSeq,
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|
strict: db.s.o.GetStrict(opt.StrictCompaction),
|
|
tableSize: db.s.o.GetCompactionTableSize(c.sourceLevel + 1),
|
|
}
|
|
db.compactionTransact("table@build", b)
|
|
|
|
// Commit.
|
|
stats[1].startTimer()
|
|
db.compactionCommit("table", rec)
|
|
stats[1].stopTimer()
|
|
|
|
resultSize := int(stats[1].write)
|
|
db.logf("table@compaction committed F%s S%s Ke·%d D·%d T·%v", sint(len(rec.addedTables)-len(rec.deletedTables)), sshortenb(resultSize-sourceSize), b.kerrCnt, b.dropCnt, stats[1].duration)
|
|
|
|
// Save compaction stats
|
|
for i := range stats {
|
|
db.compStats.addStat(c.sourceLevel+1, &stats[i])
|
|
}
|
|
}
|
|
|
|
func (db *DB) tableRangeCompaction(level int, umin, umax []byte) error {
|
|
db.logf("table@compaction range L%d %q:%q", level, umin, umax)
|
|
if level >= 0 {
|
|
if c := db.s.getCompactionRange(level, umin, umax, true); c != nil {
|
|
db.tableCompaction(c, true)
|
|
}
|
|
} else {
|
|
// Retry until nothing to compact.
|
|
for {
|
|
compacted := false
|
|
|
|
// Scan for maximum level with overlapped tables.
|
|
v := db.s.version()
|
|
m := 1
|
|
for i := m; i < len(v.levels); i++ {
|
|
tables := v.levels[i]
|
|
if tables.overlaps(db.s.icmp, umin, umax, false) {
|
|
m = i
|
|
}
|
|
}
|
|
v.release()
|
|
|
|
for level := 0; level < m; level++ {
|
|
if c := db.s.getCompactionRange(level, umin, umax, false); c != nil {
|
|
db.tableCompaction(c, true)
|
|
compacted = true
|
|
}
|
|
}
|
|
|
|
if !compacted {
|
|
break
|
|
}
|
|
}
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
func (db *DB) tableAutoCompaction() {
|
|
if c := db.s.pickCompaction(); c != nil {
|
|
db.tableCompaction(c, false)
|
|
}
|
|
}
|
|
|
|
func (db *DB) tableNeedCompaction() bool {
|
|
v := db.s.version()
|
|
defer v.release()
|
|
return v.needCompaction()
|
|
}
|
|
|
|
// resumeWrite returns an indicator whether we should resume write operation if enough level0 files are compacted.
|
|
func (db *DB) resumeWrite() bool {
|
|
v := db.s.version()
|
|
defer v.release()
|
|
if v.tLen(0) < db.s.o.GetWriteL0PauseTrigger() {
|
|
return true
|
|
}
|
|
return false
|
|
}
|
|
|
|
func (db *DB) pauseCompaction(ch chan<- struct{}) {
|
|
select {
|
|
case ch <- struct{}{}:
|
|
case <-db.closeC:
|
|
db.compactionExitTransact()
|
|
}
|
|
}
|
|
|
|
type cCmd interface {
|
|
ack(err error)
|
|
}
|
|
|
|
type cAuto struct {
|
|
// Note for table compaction, an non-empty ackC represents it's a compaction waiting command.
|
|
ackC chan<- error
|
|
}
|
|
|
|
func (r cAuto) ack(err error) {
|
|
if r.ackC != nil {
|
|
defer func() {
|
|
recover()
|
|
}()
|
|
r.ackC <- err
|
|
}
|
|
}
|
|
|
|
type cRange struct {
|
|
level int
|
|
min, max []byte
|
|
ackC chan<- error
|
|
}
|
|
|
|
func (r cRange) ack(err error) {
|
|
if r.ackC != nil {
|
|
defer func() {
|
|
recover()
|
|
}()
|
|
r.ackC <- err
|
|
}
|
|
}
|
|
|
|
// This will trigger auto compaction but will not wait for it.
|
|
func (db *DB) compTrigger(compC chan<- cCmd) {
|
|
select {
|
|
case compC <- cAuto{}:
|
|
default:
|
|
}
|
|
}
|
|
|
|
// This will trigger auto compaction and/or wait for all compaction to be done.
|
|
func (db *DB) compTriggerWait(compC chan<- cCmd) (err error) {
|
|
ch := make(chan error)
|
|
defer close(ch)
|
|
// Send cmd.
|
|
select {
|
|
case compC <- cAuto{ch}:
|
|
case err = <-db.compErrC:
|
|
return
|
|
case <-db.closeC:
|
|
return ErrClosed
|
|
}
|
|
// Wait cmd.
|
|
select {
|
|
case err = <-ch:
|
|
case err = <-db.compErrC:
|
|
case <-db.closeC:
|
|
return ErrClosed
|
|
}
|
|
return err
|
|
}
|
|
|
|
// Send range compaction request.
|
|
func (db *DB) compTriggerRange(compC chan<- cCmd, level int, min, max []byte) (err error) {
|
|
ch := make(chan error)
|
|
defer close(ch)
|
|
// Send cmd.
|
|
select {
|
|
case compC <- cRange{level, min, max, ch}:
|
|
case err := <-db.compErrC:
|
|
return err
|
|
case <-db.closeC:
|
|
return ErrClosed
|
|
}
|
|
// Wait cmd.
|
|
select {
|
|
case err = <-ch:
|
|
case err = <-db.compErrC:
|
|
case <-db.closeC:
|
|
return ErrClosed
|
|
}
|
|
return err
|
|
}
|
|
|
|
func (db *DB) mCompaction() {
|
|
var x cCmd
|
|
|
|
defer func() {
|
|
if x := recover(); x != nil {
|
|
if x != errCompactionTransactExiting {
|
|
panic(x)
|
|
}
|
|
}
|
|
if x != nil {
|
|
x.ack(ErrClosed)
|
|
}
|
|
db.closeW.Done()
|
|
}()
|
|
|
|
for {
|
|
select {
|
|
case x = <-db.mcompCmdC:
|
|
switch x.(type) {
|
|
case cAuto:
|
|
db.memCompaction()
|
|
x.ack(nil)
|
|
x = nil
|
|
default:
|
|
panic("leveldb: unknown command")
|
|
}
|
|
case <-db.closeC:
|
|
return
|
|
}
|
|
}
|
|
}
|
|
|
|
func (db *DB) tCompaction() {
|
|
var (
|
|
x cCmd
|
|
waitQ []cCmd
|
|
)
|
|
|
|
defer func() {
|
|
if x := recover(); x != nil {
|
|
if x != errCompactionTransactExiting {
|
|
panic(x)
|
|
}
|
|
}
|
|
for i := range waitQ {
|
|
waitQ[i].ack(ErrClosed)
|
|
waitQ[i] = nil
|
|
}
|
|
if x != nil {
|
|
x.ack(ErrClosed)
|
|
}
|
|
db.closeW.Done()
|
|
}()
|
|
|
|
for {
|
|
if db.tableNeedCompaction() {
|
|
select {
|
|
case x = <-db.tcompCmdC:
|
|
case ch := <-db.tcompPauseC:
|
|
db.pauseCompaction(ch)
|
|
continue
|
|
case <-db.closeC:
|
|
return
|
|
default:
|
|
}
|
|
// Resume write operation as soon as possible.
|
|
if len(waitQ) > 0 && db.resumeWrite() {
|
|
for i := range waitQ {
|
|
waitQ[i].ack(nil)
|
|
waitQ[i] = nil
|
|
}
|
|
waitQ = waitQ[:0]
|
|
}
|
|
} else {
|
|
for i := range waitQ {
|
|
waitQ[i].ack(nil)
|
|
waitQ[i] = nil
|
|
}
|
|
waitQ = waitQ[:0]
|
|
select {
|
|
case x = <-db.tcompCmdC:
|
|
case ch := <-db.tcompPauseC:
|
|
db.pauseCompaction(ch)
|
|
continue
|
|
case <-db.closeC:
|
|
return
|
|
}
|
|
}
|
|
if x != nil {
|
|
switch cmd := x.(type) {
|
|
case cAuto:
|
|
if cmd.ackC != nil {
|
|
// Check the write pause state before caching it.
|
|
if db.resumeWrite() {
|
|
x.ack(nil)
|
|
} else {
|
|
waitQ = append(waitQ, x)
|
|
}
|
|
}
|
|
case cRange:
|
|
x.ack(db.tableRangeCompaction(cmd.level, cmd.min, cmd.max))
|
|
default:
|
|
panic("leveldb: unknown command")
|
|
}
|
|
x = nil
|
|
}
|
|
db.tableAutoCompaction()
|
|
}
|
|
}
|