includes/jobqueue/JobRunner.php

   1 <?php
   2 /**
   3  * Job queue runner utility methods
   4  *
   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.
   9  *
  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.
  14  *
  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
  19  *
  20  * @file
  21  * @ingroup JobQueue
  22  */
  23
  24 use MediaWiki\MediaWikiServices;
  25 use MediaWiki\Logger\LoggerFactory;
  26 use Liuggio\StatsdClient\Factory\StatsdDataFactory;
  27 use Psr\Log\LoggerAwareInterface;
  28 use Psr\Log\LoggerInterface;
  29 use Wikimedia\ScopedCallback;
  30 use Wikimedia\Rdbms\LBFactory;
  31 use Wikimedia\Rdbms\DBError;
  32 use Wikimedia\Rdbms\DBReplicationWaitError;
  33
  34 /**
  35  * Job queue runner utility methods
  36  *
  37  * @ingroup JobQueue
  38  * @since 1.24
  39  */
  40 class JobRunner implements LoggerAwareInterface {
  41         /** @var Config */
  42         protected $config;
  43         /** @var callable|null Debug output handler */
  44         protected $debug;
  45
  46         /**
  47          * @var LoggerInterface $logger
  48          */
  49         protected $logger;
  50
  51         const MAX_ALLOWED_LAG = 3; // abort if more than this much DB lag is present
  52         const LAG_CHECK_PERIOD = 1.0; // check replica DB lag this many seconds
  53         const ERROR_BACKOFF_TTL = 1; // seconds to back off a queue due to errors
  54         const READONLY_BACKOFF_TTL = 30; // seconds to back off a queue due to read-only errors
  55
  56         /**
  57          * @param callable $debug Optional debug output handler
  58          */
  59         public function setDebugHandler( $debug ) {
  60                 $this->debug = $debug;
  61         }
  62
  63         /**
  64          * @param LoggerInterface $logger
  65          * @return void
  66          */
  67         public function setLogger( LoggerInterface $logger ) {
  68                 $this->logger = $logger;
  69         }
  70
  71         /**
  72          * @param LoggerInterface $logger
  73          */
  74         public function __construct( LoggerInterface $logger = null ) {
  75                 if ( $logger === null ) {
  76                         $logger = LoggerFactory::getInstance( 'runJobs' );
  77                 }
  78                 $this->setLogger( $logger );
  79                 $this->config = MediaWikiServices::getInstance()->getMainConfig();
  80         }
  81
  82         /**
  83          * Run jobs of the specified number/type for the specified time
  84          *
  85          * The response map has a 'job' field that lists status of each job, including:
  86          *   - type   : the job type
  87          *   - status : ok/failed
  88          *   - error  : any error message string
  89          *   - time   : the job run time in ms
  90          * The response map also has:
  91          *   - backoffs : the (job type => seconds) map of backoff times
  92          *   - elapsed  : the total time spent running tasks in ms
  93          *   - reached  : the reason the script finished, one of (none-ready, job-limit, time-limit,
  94          *  memory-limit)
  95          *
  96          * This method outputs status information only if a debug handler was set.
  97          * Any exceptions are caught and logged, but are not reported as output.
  98          *
  99          * @param array $options Map of parameters:
 100          *    - type     : the job type (or false for the default types)
 101          *    - maxJobs  : maximum number of jobs to run
 102          *    - maxTime  : maximum time in seconds before stopping
 103          *    - throttle : whether to respect job backoff configuration
 104          * @return array Summary response that can easily be JSON serialized
 105          */
 106         public function run( array $options ) {
 107                 $jobClasses = $this->config->get( 'JobClasses' );
 108                 $profilerLimits = $this->config->get( 'TrxProfilerLimits' );
 109
 110                 $response = [ 'jobs' => [], 'reached' => 'none-ready' ];
 111
 112                 $type = isset( $options['type'] ) ? $options['type'] : false;
 113                 $maxJobs = isset( $options['maxJobs'] ) ? $options['maxJobs'] : false;
 114                 $maxTime = isset( $options['maxTime'] ) ? $options['maxTime'] : false;
 115                 $noThrottle = isset( $options['throttle'] ) && !$options['throttle'];
 116
 117                 // Bail if job type is invalid
 118                 if ( $type !== false && !isset( $jobClasses[$type] ) ) {
 119                         $response['reached'] = 'none-possible';
 120                         return $response;
 121                 }
 122                 // Bail out if DB is in read-only mode
 123                 if ( wfReadOnly() ) {
 124                         $response['reached'] = 'read-only';
 125                         return $response;
 126                 }
 127
 128                 $lbFactory = MediaWikiServices::getInstance()->getDBLoadBalancerFactory();
 129                 // Bail out if there is too much DB lag.
 130                 // This check should not block as we want to try other wiki queues.
 131                 list( , $maxLag ) = $lbFactory->getMainLB( wfWikiID() )->getMaxLag();
 132                 if ( $maxLag >= self::MAX_ALLOWED_LAG ) {
 133                         $response['reached'] = 'replica-lag-limit';
 134                         return $response;
 135                 }
 136
 137                 // Flush any pending DB writes for sanity
 138                 $lbFactory->commitAll( __METHOD__ );
 139
 140                 // Catch huge single updates that lead to replica DB lag
 141                 $trxProfiler = Profiler::instance()->getTransactionProfiler();
 142                 $trxProfiler->setLogger( LoggerFactory::getInstance( 'DBPerformance' ) );
 143                 $trxProfiler->setExpectations( $profilerLimits['JobRunner'], __METHOD__ );
 144
 145                 // Some jobs types should not run until a certain timestamp
 146                 $backoffs = []; // map of (type => UNIX expiry)
 147                 $backoffDeltas = []; // map of (type => seconds)
 148                 $wait = 'wait'; // block to read backoffs the first time
 149
 150                 $group = JobQueueGroup::singleton();
 151                 $stats = MediaWikiServices::getInstance()->getStatsdDataFactory();
 152                 $jobsPopped = 0;
 153                 $timeMsTotal = 0;
 154                 $startTime = microtime( true ); // time since jobs started running
 155                 $lastCheckTime = 1; // timestamp of last replica DB check
 156                 do {
 157                         // Sync the persistent backoffs with concurrent runners
 158                         $backoffs = $this->syncBackoffDeltas( $backoffs, $backoffDeltas, $wait );
 159                         $blacklist = $noThrottle ? [] : array_keys( $backoffs );
 160                         $wait = 'nowait'; // less important now
 161
 162                         if ( $type === false ) {
 163                                 $job = $group->pop(
 164                                         JobQueueGroup::TYPE_DEFAULT,
 165                                         JobQueueGroup::USE_CACHE,
 166                                         $blacklist
 167                                 );
 168                         } elseif ( in_array( $type, $blacklist ) ) {
 169                                 $job = false; // requested queue in backoff state
 170                         } else {
 171                                 $job = $group->pop( $type ); // job from a single queue
 172                         }
 173                         $lbFactory->commitMasterChanges( __METHOD__ ); // flush any JobQueueDB writes
 174
 175                         if ( $job ) { // found a job
 176                                 ++$jobsPopped;
 177                                 $popTime = time();
 178                                 $jType = $job->getType();
 179
 180                                 WebRequest::overrideRequestId( $job->getRequestId() );
 181
 182                                 // Back off of certain jobs for a while (for throttling and for errors)
 183                                 $ttw = $this->getBackoffTimeToWait( $job );
 184                                 if ( $ttw > 0 ) {
 185                                         // Always add the delta for other runners in case the time running the
 186                                         // job negated the backoff for each individually but not collectively.
 187                                         $backoffDeltas[$jType] = isset( $backoffDeltas[$jType] )
 188                                                 ? $backoffDeltas[$jType] + $ttw
 189                                                 : $ttw;
 190                                         $backoffs = $this->syncBackoffDeltas( $backoffs, $backoffDeltas, $wait );
 191                                 }
 192
 193                                 $info = $this->executeJob( $job, $lbFactory, $stats, $popTime );
 194                                 if ( $info['status'] !== false || !$job->allowRetries() ) {
 195                                         $group->ack( $job ); // succeeded or job cannot be retried
 196                                         $lbFactory->commitMasterChanges( __METHOD__ ); // flush any JobQueueDB writes
 197                                 }
 198
 199                                 // Back off of certain jobs for a while (for throttling and for errors)
 200                                 if ( $info['status'] === false && mt_rand( 0, 49 ) == 0 ) {
 201                                         $ttw = max( $ttw, $this->getErrorBackoffTTL( $info['error'] ) );
 202                                         $backoffDeltas[$jType] = isset( $backoffDeltas[$jType] )
 203                                                 ? $backoffDeltas[$jType] + $ttw
 204                                                 : $ttw;
 205                                 }
 206
 207                                 $response['jobs'][] = [
 208                                         'type'   => $jType,
 209                                         'status' => ( $info['status'] === false ) ? 'failed' : 'ok',
 210                                         'error'  => $info['error'],
 211                                         'time'   => $info['timeMs']
 212                                 ];
 213                                 $timeMsTotal += $info['timeMs'];
 214
 215                                 // Break out if we hit the job count or wall time limits...
 216                                 if ( $maxJobs && $jobsPopped >= $maxJobs ) {
 217                                         $response['reached'] = 'job-limit';
 218                                         break;
 219                                 } elseif ( $maxTime && ( microtime( true ) - $startTime ) > $maxTime ) {
 220                                         $response['reached'] = 'time-limit';
 221                                         break;
 222                                 }
 223
 224                                 // Don't let any of the main DB replica DBs get backed up.
 225                                 // This only waits for so long before exiting and letting
 226                                 // other wikis in the farm (on different masters) get a chance.
 227                                 $timePassed = microtime( true ) - $lastCheckTime;
 228                                 if ( $timePassed >= self::LAG_CHECK_PERIOD || $timePassed < 0 ) {
 229                                         try {
 230                                                 $lbFactory->waitForReplication( [
 231                                                         'ifWritesSince' => $lastCheckTime,
 232                                                         'timeout' => self::MAX_ALLOWED_LAG
 233                                                 ] );
 234                                         } catch ( DBReplicationWaitError $e ) {
 235                                                 $response['reached'] = 'replica-lag-limit';
 236                                                 break;
 237                                         }
 238                                         $lastCheckTime = microtime( true );
 239                                 }
 240                                 // Don't let any queue replica DBs/backups fall behind
 241                                 if ( $jobsPopped > 0 && ( $jobsPopped % 100 ) == 0 ) {
 242                                         $group->waitForBackups();
 243                                 }
 244
 245                                 // Bail if near-OOM instead of in a job
 246                                 if ( !$this->checkMemoryOK() ) {
 247                                         $response['reached'] = 'memory-limit';
 248                                         break;
 249                                 }
 250                         }
 251                 } while ( $job ); // stop when there are no jobs
 252
 253                 // Sync the persistent backoffs for the next runJobs.php pass
 254                 if ( $backoffDeltas ) {
 255                         $this->syncBackoffDeltas( $backoffs, $backoffDeltas, 'wait' );
 256                 }
 257
 258                 $response['backoffs'] = $backoffs;
 259                 $response['elapsed'] = $timeMsTotal;
 260
 261                 return $response;
 262         }
 263
 264         /**
 265          * @param string $error
 266          * @return int TTL in seconds
 267          */
 268         private function getErrorBackoffTTL( $error ) {
 269                 return strpos( $error, 'DBReadOnlyError' ) !== false
 270                         ? self::READONLY_BACKOFF_TTL
 271                         : self::ERROR_BACKOFF_TTL;
 272         }
 273
 274         /**
 275          * @param Job $job
 276          * @param LBFactory $lbFactory
 277          * @param StatsdDataFactory $stats
 278          * @param float $popTime
 279          * @return array Map of status/error/timeMs
 280          */
 281         private function executeJob( Job $job, LBFactory $lbFactory, $stats, $popTime ) {
 282                 $jType = $job->getType();
 283                 $msg = $job->toString() . " STARTING";
 284                 $this->logger->debug( $msg, [
 285                         'job_type' => $job->getType(),
 286                 ] );
 287                 $this->debugCallback( $msg );
 288
 289                 // Run the job...
 290                 $rssStart = $this->getMaxRssKb();
 291                 $jobStartTime = microtime( true );
 292                 try {
 293                         $fnameTrxOwner = get_class( $job ) . '::run'; // give run() outer scope
 294                         $lbFactory->beginMasterChanges( $fnameTrxOwner );
 295                         $status = $job->run();
 296                         $error = $job->getLastError();
 297                         $this->commitMasterChanges( $lbFactory, $job, $fnameTrxOwner );
 298                         // Important: this must be the last deferred update added (T100085, T154425)
 299                         DeferredUpdates::addCallableUpdate( [ JobQueueGroup::class, 'pushLazyJobs' ] );
 300                         // Run any deferred update tasks; doUpdates() manages transactions itself
 301                         DeferredUpdates::doUpdates();
 302                 } catch ( Exception $e ) {
 303                         MWExceptionHandler::rollbackMasterChangesAndLog( $e );
 304                         $status = false;
 305                         $error = get_class( $e ) . ': ' . $e->getMessage();
 306                 }
 307                 // Always attempt to call teardown() even if Job throws exception.
 308                 try {
 309                         $job->teardown( $status );
 310                 } catch ( Exception $e ) {
 311                         MWExceptionHandler::logException( $e );
 312                 }
 313
 314                 // Commit all outstanding connections that are in a transaction
 315                 // to get a fresh repeatable read snapshot on every connection.
 316                 // Note that jobs are still responsible for handling replica DB lag.
 317                 $lbFactory->flushReplicaSnapshots( __METHOD__ );
 318                 // Clear out title cache data from prior snapshots
 319                 MediaWikiServices::getInstance()->getLinkCache()->clear();
 320                 $timeMs = intval( ( microtime( true ) - $jobStartTime ) * 1000 );
 321                 $rssEnd = $this->getMaxRssKb();
 322
 323                 // Record how long jobs wait before getting popped
 324                 $readyTs = $job->getReadyTimestamp();
 325                 if ( $readyTs ) {
 326                         $pickupDelay = max( 0, $popTime - $readyTs );
 327                         $stats->timing( 'jobqueue.pickup_delay.all', 1000 * $pickupDelay );
 328                         $stats->timing( "jobqueue.pickup_delay.$jType", 1000 * $pickupDelay );
 329                 }
 330                 // Record root job age for jobs being run
 331                 $rootTimestamp = $job->getRootJobParams()['rootJobTimestamp'];
 332                 if ( $rootTimestamp ) {
 333                         $age = max( 0, $popTime - wfTimestamp( TS_UNIX, $rootTimestamp ) );
 334                         $stats->timing( "jobqueue.pickup_root_age.$jType", 1000 * $age );
 335                 }
 336                 // Track the execution time for jobs
 337                 $stats->timing( "jobqueue.run.$jType", $timeMs );
 338                 // Track RSS increases for jobs (in case of memory leaks)
 339                 if ( $rssStart && $rssEnd ) {
 340                         $stats->updateCount( "jobqueue.rss_delta.$jType", $rssEnd - $rssStart );
 341                 }
 342
 343                 if ( $status === false ) {
 344                         $msg = $job->toString() . " t={job_duration} error={job_error}";
 345                         $this->logger->error( $msg, [
 346                                 'job_type' => $job->getType(),
 347                                 'job_duration' => $timeMs,
 348                                 'job_error' => $error,
 349                         ] );
 350
 351                         $msg = $job->toString() . " t=$timeMs error={$error}";
 352                         $this->debugCallback( $msg );
 353                 } else {
 354                         $msg = $job->toString() . " t={job_duration} good";
 355                         $this->logger->info( $msg, [
 356                                 'job_type' => $job->getType(),
 357                                 'job_duration' => $timeMs,
 358                         ] );
 359
 360                         $msg = $job->toString() . " t=$timeMs good";
 361                         $this->debugCallback( $msg );
 362                 }
 363
 364                 return [ 'status' => $status, 'error' => $error, 'timeMs' => $timeMs ];
 365         }
 366
 367         /**
 368          * @return int|null Max memory RSS in kilobytes
 369          */
 370         private function getMaxRssKb() {
 371                 $info = wfGetRusage() ?: [];
 372                 // see https://linux.die.net/man/2/getrusage
 373                 return isset( $info['ru_maxrss'] ) ? (int)$info['ru_maxrss'] : null;
 374         }
 375
 376         /**
 377          * @param Job $job
 378          * @return int Seconds for this runner to avoid doing more jobs of this type
 379          * @see $wgJobBackoffThrottling
 380          */
 381         private function getBackoffTimeToWait( Job $job ) {
 382                 $throttling = $this->config->get( 'JobBackoffThrottling' );
 383
 384                 if ( !isset( $throttling[$job->getType()] ) || $job instanceof DuplicateJob ) {
 385                         return 0; // not throttled
 386                 }
 387
 388                 $itemsPerSecond = $throttling[$job->getType()];
 389                 if ( $itemsPerSecond <= 0 ) {
 390                         return 0; // not throttled
 391                 }
 392
 393                 $seconds = 0;
 394                 if ( $job->workItemCount() > 0 ) {
 395                         $exactSeconds = $job->workItemCount() / $itemsPerSecond;
 396                         // use randomized rounding
 397                         $seconds = floor( $exactSeconds );
 398                         $remainder = $exactSeconds - $seconds;
 399                         $seconds += ( mt_rand() / mt_getrandmax() < $remainder ) ? 1 : 0;
 400                 }
 401
 402                 return (int)$seconds;
 403         }
 404
 405         /**
 406          * Get the previous backoff expiries from persistent storage
 407          * On I/O or lock acquisition failure this returns the original $backoffs.
 408          *
 409          * @param array $backoffs Map of (job type => UNIX timestamp)
 410          * @param string $mode Lock wait mode - "wait" or "nowait"
 411          * @return array Map of (job type => backoff expiry timestamp)
 412          */
 413         private function loadBackoffs( array $backoffs, $mode = 'wait' ) {
 414                 $file = wfTempDir() . '/mw-runJobs-backoffs.json';
 415                 if ( is_file( $file ) ) {
 416                         $noblock = ( $mode === 'nowait' ) ? LOCK_NB : 0;
 417                         $handle = fopen( $file, 'rb' );
 418                         if ( !flock( $handle, LOCK_SH | $noblock ) ) {
 419                                 fclose( $handle );
 420                                 return $backoffs; // don't wait on lock
 421                         }
 422                         $content = stream_get_contents( $handle );
 423                         flock( $handle, LOCK_UN );
 424                         fclose( $handle );
 425                         $ctime = microtime( true );
 426                         $cBackoffs = json_decode( $content, true ) ?: [];
 427                         foreach ( $cBackoffs as $type => $timestamp ) {
 428                                 if ( $timestamp < $ctime ) {
 429                                         unset( $cBackoffs[$type] );
 430                                 }
 431                         }
 432                 } else {
 433                         $cBackoffs = [];
 434                 }
 435
 436                 return $cBackoffs;
 437         }
 438
 439         /**
 440          * Merge the current backoff expiries from persistent storage
 441          *
 442          * The $deltas map is set to an empty array on success.
 443          * On I/O or lock acquisition failure this returns the original $backoffs.
 444          *
 445          * @param array $backoffs Map of (job type => UNIX timestamp)
 446          * @param array $deltas Map of (job type => seconds)
 447          * @param string $mode Lock wait mode - "wait" or "nowait"
 448          * @return array The new backoffs account for $backoffs and the latest file data
 449          */
 450         private function syncBackoffDeltas( array $backoffs, array &$deltas, $mode = 'wait' ) {
 451                 if ( !$deltas ) {
 452                         return $this->loadBackoffs( $backoffs, $mode );
 453                 }
 454
 455                 $noblock = ( $mode === 'nowait' ) ? LOCK_NB : 0;
 456                 $file = wfTempDir() . '/mw-runJobs-backoffs.json';
 457                 $handle = fopen( $file, 'wb+' );
 458                 if ( !flock( $handle, LOCK_EX | $noblock ) ) {
 459                         fclose( $handle );
 460                         return $backoffs; // don't wait on lock
 461                 }
 462                 $ctime = microtime( true );
 463                 $content = stream_get_contents( $handle );
 464                 $cBackoffs = json_decode( $content, true ) ?: [];
 465                 foreach ( $deltas as $type => $seconds ) {
 466                         $cBackoffs[$type] = isset( $cBackoffs[$type] ) && $cBackoffs[$type] >= $ctime
 467                                 ? $cBackoffs[$type] + $seconds
 468                                 : $ctime + $seconds;
 469                 }
 470                 foreach ( $cBackoffs as $type => $timestamp ) {
 471                         if ( $timestamp < $ctime ) {
 472                                 unset( $cBackoffs[$type] );
 473                         }
 474                 }
 475                 ftruncate( $handle, 0 );
 476                 fwrite( $handle, json_encode( $cBackoffs ) );
 477                 flock( $handle, LOCK_UN );
 478                 fclose( $handle );
 479
 480                 $deltas = [];
 481
 482                 return $cBackoffs;
 483         }
 484
 485         /**
 486          * Make sure that this script is not too close to the memory usage limit.
 487          * It is better to die in between jobs than OOM right in the middle of one.
 488          * @return bool
 489          */
 490         private function checkMemoryOK() {
 491                 static $maxBytes = null;
 492                 if ( $maxBytes === null ) {
 493                         $m = [];
 494                         if ( preg_match( '!^(\d+)(k|m|g|)$!i', ini_get( 'memory_limit' ), $m ) ) {
 495                                 list( , $num, $unit ) = $m;
 496                                 $conv = [ 'g' => 1073741824, 'm' => 1048576, 'k' => 1024, '' => 1 ];
 497                                 $maxBytes = $num * $conv[strtolower( $unit )];
 498                         } else {
 499                                 $maxBytes = 0;
 500                         }
 501                 }
 502                 $usedBytes = memory_get_usage();
 503                 if ( $maxBytes && $usedBytes >= 0.95 * $maxBytes ) {
 504                         $msg = "Detected excessive memory usage ({used_bytes}/{max_bytes}).";
 505                         $this->logger->error( $msg, [
 506                                 'used_bytes' => $usedBytes,
 507                                 'max_bytes' => $maxBytes,
 508                         ] );
 509
 510                         $msg = "Detected excessive memory usage ($usedBytes/$maxBytes).";
 511                         $this->debugCallback( $msg );
 512
 513                         return false;
 514                 }
 515
 516                 return true;
 517         }
 518
 519         /**
 520          * Log the job message
 521          * @param string $msg The message to log
 522          */
 523         private function debugCallback( $msg ) {
 524                 if ( $this->debug ) {
 525                         call_user_func_array( $this->debug, [ wfTimestamp( TS_DB ) . " $msg\n" ] );
 526                 }
 527         }
 528
 529         /**
 530          * Issue a commit on all masters who are currently in a transaction and have
 531          * made changes to the database. It also supports sometimes waiting for the
 532          * local wiki's replica DBs to catch up. See the documentation for
 533          * $wgJobSerialCommitThreshold for more.
 534          *
 535          * @param LBFactory $lbFactory
 536          * @param Job $job
 537          * @param string $fnameTrxOwner
 538          * @throws DBError
 539          */
 540         private function commitMasterChanges( LBFactory $lbFactory, Job $job, $fnameTrxOwner ) {
 541                 $syncThreshold = $this->config->get( 'JobSerialCommitThreshold' );
 542
 543                 $time = false;
 544                 $lb = $lbFactory->getMainLB( wfWikiID() );
 545                 if ( $syncThreshold !== false && $lb->getServerCount() > 1 ) {
 546                         // Generally, there is one master connection to the local DB
 547                         $dbwSerial = $lb->getAnyOpenConnection( $lb->getWriterIndex() );
 548                         // We need natively blocking fast locks
 549                         if ( $dbwSerial && $dbwSerial->namedLocksEnqueue() ) {
 550                                 $time = $dbwSerial->pendingWriteQueryDuration( $dbwSerial::ESTIMATE_DB_APPLY );
 551                                 if ( $time < $syncThreshold ) {
 552                                         $dbwSerial = false;
 553                                 }
 554                         } else {
 555                                 $dbwSerial = false;
 556                         }
 557                 } else {
 558                         // There are no replica DBs or writes are all to foreign DB (we don't handle that)
 559                         $dbwSerial = false;
 560                 }
 561
 562                 if ( !$dbwSerial ) {
 563                         $lbFactory->commitMasterChanges(
 564                                 $fnameTrxOwner,
 565                                 // Abort if any transaction was too big
 566                                 [ 'maxWriteDuration' => $this->config->get( 'MaxJobDBWriteDuration' ) ]
 567                         );
 568
 569                         return;
 570                 }
 571
 572                 $ms = intval( 1000 * $time );
 573
 574                 $msg = $job->toString() . " COMMIT ENQUEUED [{job_commit_write_ms}ms of writes]";
 575                 $this->logger->info( $msg, [
 576                         'job_type' => $job->getType(),
 577                         'job_commit_write_ms' => $ms,
 578                 ] );
 579
 580                 $msg = $job->toString() . " COMMIT ENQUEUED [{$ms}ms of writes]";
 581                 $this->debugCallback( $msg );
 582
 583                 // Wait for an exclusive lock to commit
 584                 if ( !$dbwSerial->lock( 'jobrunner-serial-commit', __METHOD__, 30 ) ) {
 585                         // This will trigger a rollback in the main loop
 586                         throw new DBError( $dbwSerial, "Timed out waiting on commit queue." );
 587                 }
 588                 $unlocker = new ScopedCallback( function () use ( $dbwSerial ) {
 589                         $dbwSerial->unlock( 'jobrunner-serial-commit', __METHOD__ );
 590                 } );
 591
 592                 // Wait for the replica DBs to catch up
 593                 $pos = $lb->getMasterPos();
 594                 if ( $pos ) {
 595                         $lb->waitForAll( $pos );
 596                 }
 597
 598                 // Actually commit the DB master changes
 599                 $lbFactory->commitMasterChanges(
 600                         $fnameTrxOwner,
 601                         // Abort if any transaction was too big
 602                         [ 'maxWriteDuration' => $this->config->get( 'MaxJobDBWriteDuration' ) ]
 603                 );
 604                 ScopedCallback::consume( $unlocker );
 605         }
 606 }