forked from blevesearch/bleve
/
garbage.go
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/
garbage.go
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// Copyright (c) 2015 Couchbase, 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, 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 firestorm
import (
"math"
"sync"
"time"
)
const DefaultGarbageThreshold = 10
const DefaultMaxDocsPerPass = 1000
var DefaultGarbageSleep = 15 * time.Second
type GarbageCollector struct {
f *Firestorm
garbageThreshold int
garbageSleep time.Duration
maxDocsPerPass int
quit chan struct{}
mutex sync.RWMutex
workingSet map[uint64][]byte
closeWait sync.WaitGroup
}
func NewGarbageCollector(f *Firestorm) *GarbageCollector {
rv := GarbageCollector{
f: f,
garbageThreshold: DefaultGarbageThreshold,
garbageSleep: DefaultGarbageSleep,
maxDocsPerPass: DefaultMaxDocsPerPass,
quit: make(chan struct{}),
workingSet: make(map[uint64][]byte),
}
return &rv
}
func (gc *GarbageCollector) Notify(docNum uint64, docId []byte) {
gc.mutex.Lock()
defer gc.mutex.Unlock()
gc.workingSet[docNum] = docId
}
func (gc *GarbageCollector) Start() {
gc.closeWait.Add(1)
go gc.run()
}
func (gc *GarbageCollector) Stop() {
close(gc.quit)
gc.closeWait.Wait()
}
func (gc *GarbageCollector) run() {
tick := time.Tick(gc.garbageSleep)
for {
select {
case <-gc.quit:
logger.Printf("garbage collector asked to quit")
gc.closeWait.Done()
return
case <-tick:
logger.Printf("garbage collector ticked")
garbageSize := gc.f.compensator.GarbageCount()
docSize, err := gc.f.DocCount()
if err != nil {
logger.Printf("garbage collector error getting doc count: %v", err)
continue
}
if docSize == 0 {
continue
}
garbageRatio := int(uint64(garbageSize) / docSize)
if garbageRatio > gc.garbageThreshold {
gc.cleanup()
} else {
logger.Printf("garbage ratio only %d, waiting", garbageRatio)
}
}
}
}
func (gc *GarbageCollector) NextBatch(n int) []uint64 {
gc.mutex.RLock()
defer gc.mutex.RUnlock()
rv := make([]uint64, 0, n)
i := 0
for k := range gc.workingSet {
rv = append(rv, k)
i++
if i > n {
break
}
}
return rv
}
func (gc *GarbageCollector) cleanup() {
logger.Printf("garbage collector starting")
// get list of deleted doc numbers to work on this pass
deletedDocNumsList := gc.NextBatch(gc.maxDocsPerPass) //gc.f.deletedDocNumbers.Keys(gc.maxDocsPerPass)
logger.Printf("found %d doc numbers to cleanup", len(deletedDocNumsList))
// put these documents numbers in a map, for faster checking
// and for organized keys to be deleted
deletedDocNums := make(map[uint64][][]byte)
for _, deletedDocNum := range deletedDocNumsList {
deletedDocNums[deletedDocNum] = make([][]byte, 0)
}
reader, err := gc.f.store.Reader()
if err != nil {
logger.Printf("garbage collector fatal: %v", err)
return
}
defer func() {
if cerr := reader.Close(); err == nil && cerr != nil {
err = cerr
}
}()
// walk all the term freq rows (where field > 0)
termFreqStart := TermFreqIteratorStart(0, []byte{ByteSeparator})
termFreqEnd := TermFreqIteratorStart(math.MaxUint16, []byte{ByteSeparator})
var tfr TermFreqRow
dictionaryDeltas := make(map[string]int64)
err = visitRange(reader, termFreqStart, termFreqEnd, func(key, val []byte) (bool, error) {
err := tfr.ParseKey(key)
if err != nil {
return false, err
}
docNum := tfr.DocNum()
if docNumKeys, deleted := deletedDocNums[docNum]; deleted {
// this doc number has been deleted, place key into map
deletedDocNums[docNum] = append(docNumKeys, key)
if tfr.Field() != 0 {
drk := tfr.DictionaryRowKey()
dictionaryDeltas[string(drk)] -= 1
}
}
return true, nil
})
if err != nil {
logger.Printf("garbage collector fatal: %v", err)
return
}
// walk all the stored rows
var sr StoredRow
err = visitPrefix(reader, StoredKeyPrefix, func(key, val []byte) (bool, error) {
err := sr.ParseKey(key)
if err != nil {
return false, err
}
docNum := sr.DocNum()
if docNumKeys, deleted := deletedDocNums[docNum]; deleted {
// this doc number has been deleted, place key into map
deletedDocNums[docNum] = append(docNumKeys, key)
}
return true, nil
})
if err != nil {
logger.Printf("garbage collector fatal: %v", err)
return
}
// now process each doc one at a time
for docNum, docKeys := range deletedDocNums {
// delete keys for a doc number
logger.Printf("deleting keys for %d", docNum)
// open a writer
writer, err := gc.f.store.Writer()
if err != nil {
_ = writer.Close()
logger.Printf("garbage collector fatal: %v", err)
return
}
// prepare batch
wb := writer.NewBatch()
for _, k := range docKeys {
wb.Delete(k)
}
err = writer.ExecuteBatch(wb)
if err != nil {
_ = writer.Close()
logger.Printf("garbage collector fatal: %v", err)
return
}
logger.Printf("deleted %d keys", len(docKeys))
// remove it from delete keys list
docID := gc.workingSet[docNum]
delete(gc.workingSet, docNum)
gc.f.compensator.GarbageCollect([]uint64{docNum})
// now delete the original marker row (field 0)
tfidrow := NewTermFreqRow(0, nil, docID, docNum, 0, 0, nil)
markerRowKey := tfidrow.Key()
markerBatch := writer.NewBatch()
markerBatch.Delete(markerRowKey)
err = writer.ExecuteBatch(markerBatch)
if err != nil {
logger.Printf("garbage collector fatal: %v", err)
return
}
err = writer.Close()
if err != nil {
logger.Printf("garbage collector fatal: %v", err)
return
}
}
// updating dictionary in one batch
gc.f.dictUpdater.NotifyBatch(dictionaryDeltas)
logger.Printf("garbage collector finished")
}