Remove unused variable in ProfilerMwprof
[mediawiki.git] / includes / jobqueue / JobQueueDB.php
blob056e5a83def8def7d41596be41713c48384b8b06
1 <?php
2 /**
3 * Database-backed job queue code.
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License along
16 * with this program; if not, write to the Free Software Foundation, Inc.,
17 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
18 * http://www.gnu.org/copyleft/gpl.html
20 * @file
21 * @author Aaron Schulz
24 /**
25 * Class to handle job queues stored in the DB
27 * @ingroup JobQueue
28 * @since 1.21
30 class JobQueueDB extends JobQueue {
31 const CACHE_TTL_SHORT = 30; // integer; seconds to cache info without re-validating
32 const CACHE_TTL_LONG = 300; // integer; seconds to cache info that is kept up to date
33 const MAX_AGE_PRUNE = 604800; // integer; seconds a job can live once claimed
34 const MAX_JOB_RANDOM = 2147483647; // integer; 2^31 - 1, used for job_random
35 const MAX_OFFSET = 255; // integer; maximum number of rows to skip
37 /** @var BagOStuff */
38 protected $cache;
40 /** @var bool|string Name of an external DB cluster. False if not set */
41 protected $cluster = false;
43 /**
44 * Additional parameters include:
45 * - cluster : The name of an external cluster registered via LBFactory.
46 * If not specified, the primary DB cluster for the wiki will be used.
47 * This can be overridden with a custom cluster so that DB handles will
48 * be retrieved via LBFactory::getExternalLB() and getConnection().
49 * @param array $params
51 protected function __construct( array $params ) {
52 global $wgMemc;
54 parent::__construct( $params );
56 $this->cluster = isset( $params['cluster'] ) ? $params['cluster'] : false;
57 // Make sure that we don't use the SQL cache, which would be harmful
58 $this->cache = ( $wgMemc instanceof SqlBagOStuff ) ? new EmptyBagOStuff() : $wgMemc;
61 protected function supportedOrders() {
62 return array( 'random', 'timestamp', 'fifo' );
65 protected function optimalOrder() {
66 return 'random';
69 /**
70 * @see JobQueue::doIsEmpty()
71 * @return bool
73 protected function doIsEmpty() {
74 $key = $this->getCacheKey( 'empty' );
76 $isEmpty = $this->cache->get( $key );
77 if ( $isEmpty === 'true' ) {
78 return true;
79 } elseif ( $isEmpty === 'false' ) {
80 return false;
83 $dbr = $this->getSlaveDB();
84 try {
85 $found = $dbr->selectField( // unclaimed job
86 'job', '1', array( 'job_cmd' => $this->type, 'job_token' => '' ), __METHOD__
88 } catch ( DBError $e ) {
89 $this->throwDBException( $e );
91 $this->cache->add( $key, $found ? 'false' : 'true', self::CACHE_TTL_LONG );
93 return !$found;
96 /**
97 * @see JobQueue::doGetSize()
98 * @return int
100 protected function doGetSize() {
101 $key = $this->getCacheKey( 'size' );
103 $size = $this->cache->get( $key );
104 if ( is_int( $size ) ) {
105 return $size;
108 try {
109 $dbr = $this->getSlaveDB();
110 $size = (int)$dbr->selectField( 'job', 'COUNT(*)',
111 array( 'job_cmd' => $this->type, 'job_token' => '' ),
112 __METHOD__
114 } catch ( DBError $e ) {
115 $this->throwDBException( $e );
117 $this->cache->set( $key, $size, self::CACHE_TTL_SHORT );
119 return $size;
123 * @see JobQueue::doGetAcquiredCount()
124 * @return int
126 protected function doGetAcquiredCount() {
127 if ( $this->claimTTL <= 0 ) {
128 return 0; // no acknowledgements
131 $key = $this->getCacheKey( 'acquiredcount' );
133 $count = $this->cache->get( $key );
134 if ( is_int( $count ) ) {
135 return $count;
138 $dbr = $this->getSlaveDB();
139 try {
140 $count = (int)$dbr->selectField( 'job', 'COUNT(*)',
141 array( 'job_cmd' => $this->type, "job_token != {$dbr->addQuotes( '' )}" ),
142 __METHOD__
144 } catch ( DBError $e ) {
145 $this->throwDBException( $e );
147 $this->cache->set( $key, $count, self::CACHE_TTL_SHORT );
149 return $count;
153 * @see JobQueue::doGetAbandonedCount()
154 * @return int
155 * @throws MWException
157 protected function doGetAbandonedCount() {
158 global $wgMemc;
160 if ( $this->claimTTL <= 0 ) {
161 return 0; // no acknowledgements
164 $key = $this->getCacheKey( 'abandonedcount' );
166 $count = $wgMemc->get( $key );
167 if ( is_int( $count ) ) {
168 return $count;
171 $dbr = $this->getSlaveDB();
172 try {
173 $count = (int)$dbr->selectField( 'job', 'COUNT(*)',
174 array(
175 'job_cmd' => $this->type,
176 "job_token != {$dbr->addQuotes( '' )}",
177 "job_attempts >= " . $dbr->addQuotes( $this->maxTries )
179 __METHOD__
181 } catch ( DBError $e ) {
182 $this->throwDBException( $e );
184 $wgMemc->set( $key, $count, self::CACHE_TTL_SHORT );
186 return $count;
190 * @see JobQueue::doBatchPush()
191 * @param array $jobs
192 * @param int $flags
193 * @throws DBError|Exception
194 * @return void
196 protected function doBatchPush( array $jobs, $flags ) {
197 $dbw = $this->getMasterDB();
199 $that = $this;
200 $method = __METHOD__;
201 $dbw->onTransactionIdle(
202 function () use ( $dbw, $that, $jobs, $flags, $method ) {
203 $that->doBatchPushInternal( $dbw, $jobs, $flags, $method );
209 * This function should *not* be called outside of JobQueueDB
211 * @param IDatabase $dbw
212 * @param array $jobs
213 * @param int $flags
214 * @param string $method
215 * @throws DBError
216 * @return void
218 public function doBatchPushInternal( IDatabase $dbw, array $jobs, $flags, $method ) {
219 if ( !count( $jobs ) ) {
220 return;
223 $rowSet = array(); // (sha1 => job) map for jobs that are de-duplicated
224 $rowList = array(); // list of jobs for jobs that are are not de-duplicated
225 foreach ( $jobs as $job ) {
226 $row = $this->insertFields( $job );
227 if ( $job->ignoreDuplicates() ) {
228 $rowSet[$row['job_sha1']] = $row;
229 } else {
230 $rowList[] = $row;
234 if ( $flags & self::QOS_ATOMIC ) {
235 $dbw->begin( $method ); // wrap all the job additions in one transaction
237 try {
238 // Strip out any duplicate jobs that are already in the queue...
239 if ( count( $rowSet ) ) {
240 $res = $dbw->select( 'job', 'job_sha1',
241 array(
242 // No job_type condition since it's part of the job_sha1 hash
243 'job_sha1' => array_keys( $rowSet ),
244 'job_token' => '' // unclaimed
246 $method
248 foreach ( $res as $row ) {
249 wfDebug( "Job with hash '{$row->job_sha1}' is a duplicate.\n" );
250 unset( $rowSet[$row->job_sha1] ); // already enqueued
253 // Build the full list of job rows to insert
254 $rows = array_merge( $rowList, array_values( $rowSet ) );
255 // Insert the job rows in chunks to avoid slave lag...
256 foreach ( array_chunk( $rows, 50 ) as $rowBatch ) {
257 $dbw->insert( 'job', $rowBatch, $method );
259 JobQueue::incrStats( 'job-insert', $this->type, count( $rows ), $this->wiki );
260 JobQueue::incrStats(
261 'job-insert-duplicate',
262 $this->type,
263 count( $rowSet ) + count( $rowList ) - count( $rows ),
264 $this->wiki
266 } catch ( DBError $e ) {
267 if ( $flags & self::QOS_ATOMIC ) {
268 $dbw->rollback( $method );
270 throw $e;
272 if ( $flags & self::QOS_ATOMIC ) {
273 $dbw->commit( $method );
276 $this->cache->set( $this->getCacheKey( 'empty' ), 'false', JobQueueDB::CACHE_TTL_LONG );
278 return;
282 * @see JobQueue::doPop()
283 * @return Job|bool
285 protected function doPop() {
286 if ( $this->cache->get( $this->getCacheKey( 'empty' ) ) === 'true' ) {
287 return false; // queue is empty
290 $dbw = $this->getMasterDB();
291 try {
292 $dbw->commit( __METHOD__, 'flush' ); // flush existing transaction
293 $autoTrx = $dbw->getFlag( DBO_TRX ); // get current setting
294 $dbw->clearFlag( DBO_TRX ); // make each query its own transaction
295 $scopedReset = new ScopedCallback( function () use ( $dbw, $autoTrx ) {
296 $dbw->setFlag( $autoTrx ? DBO_TRX : 0 ); // restore old setting
297 } );
299 $uuid = wfRandomString( 32 ); // pop attempt
300 $job = false; // job popped off
301 do { // retry when our row is invalid or deleted as a duplicate
302 // Try to reserve a row in the DB...
303 if ( in_array( $this->order, array( 'fifo', 'timestamp' ) ) ) {
304 $row = $this->claimOldest( $uuid );
305 } else { // random first
306 $rand = mt_rand( 0, self::MAX_JOB_RANDOM ); // encourage concurrent UPDATEs
307 $gte = (bool)mt_rand( 0, 1 ); // find rows with rand before/after $rand
308 $row = $this->claimRandom( $uuid, $rand, $gte );
310 // Check if we found a row to reserve...
311 if ( !$row ) {
312 $this->cache->set( $this->getCacheKey( 'empty' ), 'true', self::CACHE_TTL_LONG );
313 break; // nothing to do
315 JobQueue::incrStats( 'job-pop', $this->type, 1, $this->wiki );
316 // Get the job object from the row...
317 $title = Title::makeTitleSafe( $row->job_namespace, $row->job_title );
318 if ( !$title ) {
319 $dbw->delete( 'job', array( 'job_id' => $row->job_id ), __METHOD__ );
320 wfDebug( "Row has invalid title '{$row->job_title}'.\n" );
321 continue; // try again
323 $job = Job::factory( $row->job_cmd, $title,
324 self::extractBlob( $row->job_params ), $row->job_id );
325 $job->metadata['id'] = $row->job_id;
326 break; // done
327 } while ( true );
328 } catch ( DBError $e ) {
329 $this->throwDBException( $e );
332 return $job;
336 * Reserve a row with a single UPDATE without holding row locks over RTTs...
338 * @param string $uuid 32 char hex string
339 * @param int $rand Random unsigned integer (31 bits)
340 * @param bool $gte Search for job_random >= $random (otherwise job_random <= $random)
341 * @return stdClass|bool Row|false
343 protected function claimRandom( $uuid, $rand, $gte ) {
344 $dbw = $this->getMasterDB();
345 // Check cache to see if the queue has <= OFFSET items
346 $tinyQueue = $this->cache->get( $this->getCacheKey( 'small' ) );
348 $row = false; // the row acquired
349 $invertedDirection = false; // whether one job_random direction was already scanned
350 // This uses a replication safe method for acquiring jobs. One could use UPDATE+LIMIT
351 // instead, but that either uses ORDER BY (in which case it deadlocks in MySQL) or is
352 // not replication safe. Due to http://bugs.mysql.com/bug.php?id=6980, subqueries cannot
353 // be used here with MySQL.
354 do {
355 if ( $tinyQueue ) { // queue has <= MAX_OFFSET rows
356 // For small queues, using OFFSET will overshoot and return no rows more often.
357 // Instead, this uses job_random to pick a row (possibly checking both directions).
358 $ineq = $gte ? '>=' : '<=';
359 $dir = $gte ? 'ASC' : 'DESC';
360 $row = $dbw->selectRow( 'job', self::selectFields(), // find a random job
361 array(
362 'job_cmd' => $this->type,
363 'job_token' => '', // unclaimed
364 "job_random {$ineq} {$dbw->addQuotes( $rand )}" ),
365 __METHOD__,
366 array( 'ORDER BY' => "job_random {$dir}" )
368 if ( !$row && !$invertedDirection ) {
369 $gte = !$gte;
370 $invertedDirection = true;
371 continue; // try the other direction
373 } else { // table *may* have >= MAX_OFFSET rows
374 // Bug 42614: "ORDER BY job_random" with a job_random inequality causes high CPU
375 // in MySQL if there are many rows for some reason. This uses a small OFFSET
376 // instead of job_random for reducing excess claim retries.
377 $row = $dbw->selectRow( 'job', self::selectFields(), // find a random job
378 array(
379 'job_cmd' => $this->type,
380 'job_token' => '', // unclaimed
382 __METHOD__,
383 array( 'OFFSET' => mt_rand( 0, self::MAX_OFFSET ) )
385 if ( !$row ) {
386 $tinyQueue = true; // we know the queue must have <= MAX_OFFSET rows
387 $this->cache->set( $this->getCacheKey( 'small' ), 1, 30 );
388 continue; // use job_random
392 if ( $row ) { // claim the job
393 $dbw->update( 'job', // update by PK
394 array(
395 'job_token' => $uuid,
396 'job_token_timestamp' => $dbw->timestamp(),
397 'job_attempts = job_attempts+1' ),
398 array( 'job_cmd' => $this->type, 'job_id' => $row->job_id, 'job_token' => '' ),
399 __METHOD__
401 // This might get raced out by another runner when claiming the previously
402 // selected row. The use of job_random should minimize this problem, however.
403 if ( !$dbw->affectedRows() ) {
404 $row = false; // raced out
406 } else {
407 break; // nothing to do
409 } while ( !$row );
411 return $row;
415 * Reserve a row with a single UPDATE without holding row locks over RTTs...
417 * @param string $uuid 32 char hex string
418 * @return stdClass|bool Row|false
420 protected function claimOldest( $uuid ) {
421 $dbw = $this->getMasterDB();
423 $row = false; // the row acquired
424 do {
425 if ( $dbw->getType() === 'mysql' ) {
426 // Per http://bugs.mysql.com/bug.php?id=6980, we can't use subqueries on the
427 // same table being changed in an UPDATE query in MySQL (gives Error: 1093).
428 // Oracle and Postgre have no such limitation. However, MySQL offers an
429 // alternative here by supporting ORDER BY + LIMIT for UPDATE queries.
430 $dbw->query( "UPDATE {$dbw->tableName( 'job' )} " .
431 "SET " .
432 "job_token = {$dbw->addQuotes( $uuid ) }, " .
433 "job_token_timestamp = {$dbw->addQuotes( $dbw->timestamp() )}, " .
434 "job_attempts = job_attempts+1 " .
435 "WHERE ( " .
436 "job_cmd = {$dbw->addQuotes( $this->type )} " .
437 "AND job_token = {$dbw->addQuotes( '' )} " .
438 ") ORDER BY job_id ASC LIMIT 1",
439 __METHOD__
441 } else {
442 // Use a subquery to find the job, within an UPDATE to claim it.
443 // This uses as much of the DB wrapper functions as possible.
444 $dbw->update( 'job',
445 array(
446 'job_token' => $uuid,
447 'job_token_timestamp' => $dbw->timestamp(),
448 'job_attempts = job_attempts+1' ),
449 array( 'job_id = (' .
450 $dbw->selectSQLText( 'job', 'job_id',
451 array( 'job_cmd' => $this->type, 'job_token' => '' ),
452 __METHOD__,
453 array( 'ORDER BY' => 'job_id ASC', 'LIMIT' => 1 ) ) .
456 __METHOD__
459 // Fetch any row that we just reserved...
460 if ( $dbw->affectedRows() ) {
461 $row = $dbw->selectRow( 'job', self::selectFields(),
462 array( 'job_cmd' => $this->type, 'job_token' => $uuid ), __METHOD__
464 if ( !$row ) { // raced out by duplicate job removal
465 wfDebug( "Row deleted as duplicate by another process.\n" );
467 } else {
468 break; // nothing to do
470 } while ( !$row );
472 return $row;
476 * @see JobQueue::doAck()
477 * @param Job $job
478 * @throws MWException
479 * @return Job|bool
481 protected function doAck( Job $job ) {
482 if ( !isset( $job->metadata['id'] ) ) {
483 throw new MWException( "Job of type '{$job->getType()}' has no ID." );
486 $dbw = $this->getMasterDB();
487 try {
488 $dbw->commit( __METHOD__, 'flush' ); // flush existing transaction
489 $autoTrx = $dbw->getFlag( DBO_TRX ); // get current setting
490 $dbw->clearFlag( DBO_TRX ); // make each query its own transaction
491 $scopedReset = new ScopedCallback( function () use ( $dbw, $autoTrx ) {
492 $dbw->setFlag( $autoTrx ? DBO_TRX : 0 ); // restore old setting
493 } );
495 // Delete a row with a single DELETE without holding row locks over RTTs...
496 $dbw->delete( 'job',
497 array( 'job_cmd' => $this->type, 'job_id' => $job->metadata['id'] ), __METHOD__ );
498 } catch ( DBError $e ) {
499 $this->throwDBException( $e );
502 return true;
506 * @see JobQueue::doDeduplicateRootJob()
507 * @param Job $job
508 * @throws MWException
509 * @return bool
511 protected function doDeduplicateRootJob( Job $job ) {
512 $params = $job->getParams();
513 if ( !isset( $params['rootJobSignature'] ) ) {
514 throw new MWException( "Cannot register root job; missing 'rootJobSignature'." );
515 } elseif ( !isset( $params['rootJobTimestamp'] ) ) {
516 throw new MWException( "Cannot register root job; missing 'rootJobTimestamp'." );
518 $key = $this->getRootJobCacheKey( $params['rootJobSignature'] );
519 // Callers should call batchInsert() and then this function so that if the insert
520 // fails, the de-duplication registration will be aborted. Since the insert is
521 // deferred till "transaction idle", do the same here, so that the ordering is
522 // maintained. Having only the de-duplication registration succeed would cause
523 // jobs to become no-ops without any actual jobs that made them redundant.
524 $dbw = $this->getMasterDB();
525 $cache = $this->dupCache;
526 $dbw->onTransactionIdle( function () use ( $cache, $params, $key, $dbw ) {
527 $timestamp = $cache->get( $key ); // current last timestamp of this job
528 if ( $timestamp && $timestamp >= $params['rootJobTimestamp'] ) {
529 return true; // a newer version of this root job was enqueued
532 // Update the timestamp of the last root job started at the location...
533 return $cache->set( $key, $params['rootJobTimestamp'], JobQueueDB::ROOTJOB_TTL );
534 } );
536 return true;
540 * @see JobQueue::doDelete()
541 * @return bool
543 protected function doDelete() {
544 $dbw = $this->getMasterDB();
545 try {
546 $dbw->delete( 'job', array( 'job_cmd' => $this->type ) );
547 } catch ( DBError $e ) {
548 $this->throwDBException( $e );
551 return true;
555 * @see JobQueue::doWaitForBackups()
556 * @return void
558 protected function doWaitForBackups() {
559 wfWaitForSlaves( false, $this->wiki, $this->cluster ?: false );
563 * @return array
565 protected function doGetPeriodicTasks() {
566 return array(
567 'recycleAndDeleteStaleJobs' => array(
568 'callback' => array( $this, 'recycleAndDeleteStaleJobs' ),
569 'period' => ceil( $this->claimTTL / 2 )
575 * @return void
577 protected function doFlushCaches() {
578 foreach ( array( 'empty', 'size', 'acquiredcount' ) as $type ) {
579 $this->cache->delete( $this->getCacheKey( $type ) );
584 * @see JobQueue::getAllQueuedJobs()
585 * @return Iterator
587 public function getAllQueuedJobs() {
588 $dbr = $this->getSlaveDB();
589 try {
590 return new MappedIterator(
591 $dbr->select( 'job', self::selectFields(),
592 array( 'job_cmd' => $this->getType(), 'job_token' => '' ) ),
593 function ( $row ) use ( $dbr ) {
594 $job = Job::factory(
595 $row->job_cmd,
596 Title::makeTitle( $row->job_namespace, $row->job_title ),
597 strlen( $row->job_params ) ? unserialize( $row->job_params ) : false
599 $job->metadata['id'] = $row->job_id;
600 return $job;
603 } catch ( DBError $e ) {
604 $this->throwDBException( $e );
608 public function getCoalesceLocationInternal() {
609 return $this->cluster
610 ? "DBCluster:{$this->cluster}:{$this->wiki}"
611 : "LBFactory:{$this->wiki}";
614 protected function doGetSiblingQueuesWithJobs( array $types ) {
615 $dbr = $this->getSlaveDB();
616 $res = $dbr->select( 'job', 'DISTINCT job_cmd',
617 array( 'job_cmd' => $types ), __METHOD__ );
619 $types = array();
620 foreach ( $res as $row ) {
621 $types[] = $row->job_cmd;
624 return $types;
627 protected function doGetSiblingQueueSizes( array $types ) {
628 $dbr = $this->getSlaveDB();
629 $res = $dbr->select( 'job', array( 'job_cmd', 'COUNT(*) AS count' ),
630 array( 'job_cmd' => $types ), __METHOD__, array( 'GROUP BY' => 'job_cmd' ) );
632 $sizes = array();
633 foreach ( $res as $row ) {
634 $sizes[$row->job_cmd] = (int)$row->count;
637 return $sizes;
641 * Recycle or destroy any jobs that have been claimed for too long
643 * @return int Number of jobs recycled/deleted
645 public function recycleAndDeleteStaleJobs() {
646 $now = time();
647 $count = 0; // affected rows
648 $dbw = $this->getMasterDB();
650 try {
651 if ( !$dbw->lock( "jobqueue-recycle-{$this->type}", __METHOD__, 1 ) ) {
652 return $count; // already in progress
655 // Remove claims on jobs acquired for too long if enabled...
656 if ( $this->claimTTL > 0 ) {
657 $claimCutoff = $dbw->timestamp( $now - $this->claimTTL );
658 // Get the IDs of jobs that have be claimed but not finished after too long.
659 // These jobs can be recycled into the queue by expiring the claim. Selecting
660 // the IDs first means that the UPDATE can be done by primary key (less deadlocks).
661 $res = $dbw->select( 'job', 'job_id',
662 array(
663 'job_cmd' => $this->type,
664 "job_token != {$dbw->addQuotes( '' )}", // was acquired
665 "job_token_timestamp < {$dbw->addQuotes( $claimCutoff )}", // stale
666 "job_attempts < {$dbw->addQuotes( $this->maxTries )}" ), // retries left
667 __METHOD__
669 $ids = array_map(
670 function ( $o ) {
671 return $o->job_id;
672 }, iterator_to_array( $res )
674 if ( count( $ids ) ) {
675 // Reset job_token for these jobs so that other runners will pick them up.
676 // Set the timestamp to the current time, as it is useful to now that the job
677 // was already tried before (the timestamp becomes the "released" time).
678 $dbw->update( 'job',
679 array(
680 'job_token' => '',
681 'job_token_timestamp' => $dbw->timestamp( $now ) ), // time of release
682 array(
683 'job_id' => $ids ),
684 __METHOD__
686 $affected = $dbw->affectedRows();
687 $count += $affected;
688 JobQueue::incrStats( 'job-recycle', $this->type, $affected, $this->wiki );
689 $this->cache->set( $this->getCacheKey( 'empty' ), 'false', self::CACHE_TTL_LONG );
693 // Just destroy any stale jobs...
694 $pruneCutoff = $dbw->timestamp( $now - self::MAX_AGE_PRUNE );
695 $conds = array(
696 'job_cmd' => $this->type,
697 "job_token != {$dbw->addQuotes( '' )}", // was acquired
698 "job_token_timestamp < {$dbw->addQuotes( $pruneCutoff )}" // stale
700 if ( $this->claimTTL > 0 ) { // only prune jobs attempted too many times...
701 $conds[] = "job_attempts >= {$dbw->addQuotes( $this->maxTries )}";
703 // Get the IDs of jobs that are considered stale and should be removed. Selecting
704 // the IDs first means that the UPDATE can be done by primary key (less deadlocks).
705 $res = $dbw->select( 'job', 'job_id', $conds, __METHOD__ );
706 $ids = array_map(
707 function ( $o ) {
708 return $o->job_id;
709 }, iterator_to_array( $res )
711 if ( count( $ids ) ) {
712 $dbw->delete( 'job', array( 'job_id' => $ids ), __METHOD__ );
713 $affected = $dbw->affectedRows();
714 $count += $affected;
715 JobQueue::incrStats( 'job-abandon', $this->type, $affected, $this->wiki );
718 $dbw->unlock( "jobqueue-recycle-{$this->type}", __METHOD__ );
719 } catch ( DBError $e ) {
720 $this->throwDBException( $e );
723 return $count;
727 * @param IJobSpecification $job
728 * @return array
730 protected function insertFields( IJobSpecification $job ) {
731 $dbw = $this->getMasterDB();
733 return array(
734 // Fields that describe the nature of the job
735 'job_cmd' => $job->getType(),
736 'job_namespace' => $job->getTitle()->getNamespace(),
737 'job_title' => $job->getTitle()->getDBkey(),
738 'job_params' => self::makeBlob( $job->getParams() ),
739 // Additional job metadata
740 'job_id' => $dbw->nextSequenceValue( 'job_job_id_seq' ),
741 'job_timestamp' => $dbw->timestamp(),
742 'job_sha1' => wfBaseConvert(
743 sha1( serialize( $job->getDeduplicationInfo() ) ),
744 16, 36, 31
746 'job_random' => mt_rand( 0, self::MAX_JOB_RANDOM )
751 * @throws JobQueueConnectionError
752 * @return DBConnRef
754 protected function getSlaveDB() {
755 try {
756 return $this->getDB( DB_SLAVE );
757 } catch ( DBConnectionError $e ) {
758 throw new JobQueueConnectionError( "DBConnectionError:" . $e->getMessage() );
763 * @throws JobQueueConnectionError
764 * @return DBConnRef
766 protected function getMasterDB() {
767 try {
768 return $this->getDB( DB_MASTER );
769 } catch ( DBConnectionError $e ) {
770 throw new JobQueueConnectionError( "DBConnectionError:" . $e->getMessage() );
775 * @param int $index (DB_SLAVE/DB_MASTER)
776 * @return DBConnRef
778 protected function getDB( $index ) {
779 $lb = ( $this->cluster !== false )
780 ? wfGetLBFactory()->getExternalLB( $this->cluster, $this->wiki )
781 : wfGetLB( $this->wiki );
783 return $lb->getConnectionRef( $index, array(), $this->wiki );
787 * @param string $property
788 * @return string
790 private function getCacheKey( $property ) {
791 list( $db, $prefix ) = wfSplitWikiID( $this->wiki );
792 $cluster = is_string( $this->cluster ) ? $this->cluster : 'main';
794 return wfForeignMemcKey( $db, $prefix, 'jobqueue', $cluster, $this->type, $property );
798 * @param array|bool $params
799 * @return string
801 protected static function makeBlob( $params ) {
802 if ( $params !== false ) {
803 return serialize( $params );
804 } else {
805 return '';
810 * @param string $blob
811 * @return bool|mixed
813 protected static function extractBlob( $blob ) {
814 if ( (string)$blob !== '' ) {
815 return unserialize( $blob );
816 } else {
817 return false;
822 * @param DBError $e
823 * @throws JobQueueError
825 protected function throwDBException( DBError $e ) {
826 throw new JobQueueError( get_class( $e ) . ": " . $e->getMessage() );
830 * Return the list of job fields that should be selected.
831 * @since 1.23
832 * @return array
834 public static function selectFields() {
835 return array(
836 'job_id',
837 'job_cmd',
838 'job_namespace',
839 'job_title',
840 'job_timestamp',
841 'job_params',
842 'job_random',
843 'job_attempts',
844 'job_token',
845 'job_token_timestamp',
846 'job_sha1',