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/*
* Copyright 2015 Manish R Jain <manishrjain@gmail.com>
*
* 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 posting
import (
"sync"
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"time"
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"github.com/Sirupsen/logrus"
"github.com/dgraph-io/dgraph/commit"
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type entry struct {
l *List
}
var lmutex sync.RWMutex
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var lcache map[uint64]*entry
var pstore *store.Store
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var ch chan uint64
func Init(posting *store.Store, log *commit.Logger) {
lmutex.Lock()
defer lmutex.Unlock()
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lcache = make(map[uint64]*entry)
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ch = make(chan uint64, 1000)
go queueForProcessing()
go process()
}
func get(k uint64) *List {
lmutex.RLock()
defer lmutex.RUnlock()
if e, ok := lcache[k]; ok {
return e.l
}
return nil
}
func Get(key []byte) *List {
// Acquire read lock and check if list is available.
lmutex.RLock()
uid := farm.Fingerprint64(key)
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if e, ok := lcache[uid]; ok {
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return e.l
}
lmutex.RUnlock()
// Couldn't find it. Acquire write lock.
lmutex.Lock()
defer lmutex.Unlock()
// Check again after acquiring write lock.
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if e, ok := lcache[uid]; ok {
return e.l
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e := new(entry)
e.l = new(List)
e.l.init(key, pstore, clog)
lcache[uid] = e
return e.l
}
func queueForProcessing() {
ticker := time.NewTicker(time.Minute)
for _ = range ticker.C {
count := 0
skipped := 0
lmutex.RLock()
now := time.Now()
for eid, e := range lcache {
if len(ch) >= cap(ch) {
break
}
if len(ch) < int(0.3*float32(cap(ch))) && e.l.IsDirty() {
// Let's add some work here.
ch <- eid
count += 1
} else if now.Sub(e.l.LastCompactionTs()) > 10*time.Minute {
// Only queue lists which haven't been processed for a while.
ch <- eid
count += 1
} else {
skipped += 1
}
}
lmutex.RUnlock()
glog.WithFields(logrus.Fields{
"added": count,
"skipped": skipped,
"pending": len(ch),
}).Info("Added for compaction")
}
}
func process() {
ticker := time.NewTicker(100 * time.Millisecond)
for _ = range ticker.C {
eid := <-ch // blocking.
l := get(eid)
if l == nil {
continue
}
glog.WithField("eid", eid).WithField("pending", len(ch)).
Info("Commiting list")
if err := l.CompactIfDirty(); err != nil {
glog.WithError(err).Error("While commiting dirty list.")
}
}