includes/jobqueue/jobs/ClearUserWatchlistJob.php

   1 <?php
   2
   3 use MediaWiki\MediaWikiServices;
   4
   5 /**
   6  * Job to clear a users watchlist in batches.
   7  *
   8  * @author Addshore
   9  *
  10  * @ingroup JobQueue
  11  * @since 1.31
  12  */
  13 class ClearUserWatchlistJob extends Job implements GenericParameterJob {
  14         /**
  15          * @param array $params
  16          *  - userId,         The ID for the user whose watchlist is being cleared.
  17          *  - maxWatchlistId, The maximum wl_id at the time the job was first created,
  18          */
  19         public function __construct( array $params ) {
  20                 parent::__construct( 'clearUserWatchlist', $params );
  21
  22                 $this->removeDuplicates = true;
  23         }
  24
  25         /**
  26          * @param User $user User to clear the watchlist for.
  27          * @param int $maxWatchlistId The maximum wl_id at the time the job was first created.
  28          *
  29          * @return ClearUserWatchlistJob
  30          */
  31         public static function newForUser( User $user, $maxWatchlistId ) {
  32                 return new self( [ 'userId' => $user->getId(), 'maxWatchlistId' => $maxWatchlistId ] );
  33         }
  34
  35         public function run() {
  36                 global $wgUpdateRowsPerQuery;
  37                 $userId = $this->params['userId'];
  38                 $maxWatchlistId = $this->params['maxWatchlistId'];
  39                 $batchSize = $wgUpdateRowsPerQuery;
  40
  41                 $loadBalancer = MediaWikiServices::getInstance()->getDBLoadBalancer();
  42                 $dbw = $loadBalancer->getConnection( DB_MASTER );
  43                 $dbr = $loadBalancer->getConnection( DB_REPLICA, [ 'watchlist' ] );
  44
  45                 // Wait before lock to try to reduce time waiting in the lock.
  46                 if ( !$loadBalancer->safeWaitForMasterPos( $dbr ) ) {
  47                         $this->setLastError( 'Timed out waiting for replica to catch up before lock' );
  48                         return false;
  49                 }
  50
  51                 // Use a named lock so that jobs for this user see each others' changes
  52                 $lockKey = "ClearUserWatchlistJob:$userId";
  53                 $scopedLock = $dbw->getScopedLockAndFlush( $lockKey, __METHOD__, 10 );
  54                 if ( !$scopedLock ) {
  55                         $this->setLastError( "Could not acquire lock '$lockKey'" );
  56                         return false;
  57                 }
  58
  59                 if ( !$loadBalancer->safeWaitForMasterPos( $dbr ) ) {
  60                         $this->setLastError( 'Timed out waiting for replica to catch up within lock' );
  61                         return false;
  62                 }
  63
  64                 // Clear any stale REPEATABLE-READ snapshot
  65                 $dbr->flushSnapshot( __METHOD__ );
  66
  67                 $watchlistIds = $dbr->selectFieldValues(
  68                         'watchlist',
  69                         'wl_id',
  70                         [
  71                                 'wl_user' => $userId,
  72                                 'wl_id <= ' . $maxWatchlistId
  73                         ],
  74                         __METHOD__,
  75                         [
  76                                 'ORDER BY' => 'wl_id ASC',
  77                                 'LIMIT' => $batchSize,
  78                         ]
  79                 );
  80
  81                 if ( count( $watchlistIds ) == 0 ) {
  82                         return true;
  83                 }
  84
  85                 $dbw->delete( 'watchlist', [ 'wl_id' => $watchlistIds ], __METHOD__ );
  86
  87                 // Commit changes and remove lock before inserting next job.
  88                 $lbf = MediaWikiServices::getInstance()->getDBLoadBalancerFactory();
  89                 $lbf->commitMasterChanges( __METHOD__ );
  90                 unset( $scopedLock );
  91
  92                 if ( count( $watchlistIds ) === (int)$batchSize ) {
  93                         // Until we get less results than the limit, recursively push
  94                         // the same job again.
  95                         JobQueueGroup::singleton()->push( new self( $this->getParams() ) );
  96                 }
  97
  98                 return true;
  99         }
 100
 101         public function getDeduplicationInfo() {
 102                 $info = parent::getDeduplicationInfo();
 103                 // This job never has a namespace or title so we can't use it for deduplication
 104                 unset( $info['namespace'] );
 105                 unset( $info['title'] );
 106                 return $info;
 107         }
 108
 109 }