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