includes/deferred/LinksDeletionUpdate.php

   1 <?php
   2 /**
   3  * Updater for link tracking tables after a page edit.
   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  */
  22 use MediaWiki\MediaWikiServices;
  23 use Wikimedia\ScopedCallback;
  24 use Wikimedia\Rdbms\IDatabase;
  25
  26 /**
  27  * Update object handling the cleanup of links tables after a page was deleted.
  28  */
  29 class LinksDeletionUpdate extends DataUpdate implements EnqueueableDataUpdate {
  30         /** @var WikiPage */
  31         protected $page;
  32         /** @var int */
  33         protected $pageId;
  34         /** @var string */
  35         protected $timestamp;
  36
  37         /** @var IDatabase */
  38         private $db;
  39
  40         /**
  41          * @param WikiPage $page Page we are updating
  42          * @param int|null $pageId ID of the page we are updating [optional]
  43          * @param string|null $timestamp TS_MW timestamp of deletion
  44          * @throws MWException
  45          */
  46         function __construct( WikiPage $page, $pageId = null, $timestamp = null ) {
  47                 parent::__construct();
  48
  49                 $this->page = $page;
  50                 if ( $pageId ) {
  51                         $this->pageId = $pageId; // page ID at time of deletion
  52                 } elseif ( $page->exists() ) {
  53                         $this->pageId = $page->getId();
  54                 } else {
  55                         throw new InvalidArgumentException( "Page ID not known. Page doesn't exist?" );
  56                 }
  57
  58                 $this->timestamp = $timestamp ?: wfTimestampNow();
  59         }
  60
  61         public function doUpdate() {
  62                 $services = MediaWikiServices::getInstance();
  63                 $config = $services->getMainConfig();
  64                 $lbFactory = $services->getDBLoadBalancerFactory();
  65                 $batchSize = $config->get( 'UpdateRowsPerQuery' );
  66
  67                 // Page may already be deleted, so don't just getId()
  68                 $id = $this->pageId;
  69
  70                 if ( $this->ticket ) {
  71                         // Make sure all links update threads see the changes of each other.
  72                         // This handles the case when updates have to batched into several COMMITs.
  73                         $scopedLock = LinksUpdate::acquirePageLock( $this->getDB(), $id );
  74                         if ( !$scopedLock ) {
  75                                 throw new RuntimeException( "Could not acquire lock for page ID '{$id}'." );
  76                         }
  77                 }
  78
  79                 $title = $this->page->getTitle();
  80                 $dbw = $this->getDB(); // convenience
  81
  82                 // Delete restrictions for it
  83                 $dbw->delete( 'page_restrictions', [ 'pr_page' => $id ], __METHOD__ );
  84
  85                 // Fix category table counts
  86                 $cats = $dbw->selectFieldValues(
  87                         'categorylinks',
  88                         'cl_to',
  89                         [ 'cl_from' => $id ],
  90                         __METHOD__
  91                 );
  92                 $catBatches = array_chunk( $cats, $batchSize );
  93                 foreach ( $catBatches as $catBatch ) {
  94                         $this->page->updateCategoryCounts( [], $catBatch, $id );
  95                         if ( count( $catBatches ) > 1 ) {
  96                                 // Only sacrifice atomicity if necessary due to size
  97                                 $lbFactory->commitAndWaitForReplication(
  98                                         __METHOD__, $this->ticket, [ 'domain' => $dbw->getDomainID() ]
  99                                 );
 100                         }
 101                 }
 102
 103                 // Refresh counts on categories that should be empty now
 104                 if ( $title->getNamespace() === NS_CATEGORY ) {
 105                         // T166757: do the update after the main job DB commit
 106                         DeferredUpdates::addCallableUpdate( function () use ( $title ) {
 107                                 $cat = Category::newFromName( $title->getDBkey() );
 108                                 $cat->refreshCountsIfEmpty();
 109                         } );
 110                 }
 111
 112                 $this->batchDeleteByPK(
 113                         'pagelinks',
 114                         [ 'pl_from' => $id ],
 115                         [ 'pl_from', 'pl_namespace', 'pl_title' ],
 116                         $batchSize
 117                 );
 118                 $this->batchDeleteByPK(
 119                         'imagelinks',
 120                         [ 'il_from' => $id ],
 121                         [ 'il_from', 'il_to' ],
 122                         $batchSize
 123                 );
 124                 $this->batchDeleteByPK(
 125                         'categorylinks',
 126                         [ 'cl_from' => $id ],
 127                         [ 'cl_from', 'cl_to' ],
 128                         $batchSize
 129                 );
 130                 $this->batchDeleteByPK(
 131                         'templatelinks',
 132                         [ 'tl_from' => $id ],
 133                         [ 'tl_from', 'tl_namespace', 'tl_title' ],
 134                         $batchSize
 135                 );
 136                 $this->batchDeleteByPK(
 137                         'externallinks',
 138                         [ 'el_from' => $id ],
 139                         [ 'el_id' ],
 140                         $batchSize
 141                 );
 142                 $this->batchDeleteByPK(
 143                         'langlinks',
 144                         [ 'll_from' => $id ],
 145                         [ 'll_from', 'll_lang' ],
 146                         $batchSize
 147                 );
 148                 $this->batchDeleteByPK(
 149                         'iwlinks',
 150                         [ 'iwl_from' => $id ],
 151                         [ 'iwl_from', 'iwl_prefix', 'iwl_title' ],
 152                         $batchSize
 153                 );
 154
 155                 // Delete any redirect entry or page props entries
 156                 $dbw->delete( 'redirect', [ 'rd_from' => $id ], __METHOD__ );
 157                 $dbw->delete( 'page_props', [ 'pp_page' => $id ], __METHOD__ );
 158
 159                 // Find recentchanges entries to clean up...
 160                 $rcIdsForTitle = $dbw->selectFieldValues(
 161                         'recentchanges',
 162                         'rc_id',
 163                         [
 164                                 'rc_type != ' . RC_LOG,
 165                                 'rc_namespace' => $title->getNamespace(),
 166                                 'rc_title' => $title->getDBkey(),
 167                                 'rc_timestamp < ' .
 168                                         $dbw->addQuotes( $dbw->timestamp( $this->timestamp ) )
 169                         ],
 170                         __METHOD__
 171                 );
 172                 $rcIdsForPage = $dbw->selectFieldValues(
 173                         'recentchanges',
 174                         'rc_id',
 175                         [ 'rc_type != ' . RC_LOG, 'rc_cur_id' => $id ],
 176                         __METHOD__
 177                 );
 178
 179                 // T98706: delete by PK to avoid lock contention with RC delete log insertions
 180                 $rcIdBatches = array_chunk( array_merge( $rcIdsForTitle, $rcIdsForPage ), $batchSize );
 181                 foreach ( $rcIdBatches as $rcIdBatch ) {
 182                         $dbw->delete( 'recentchanges', [ 'rc_id' => $rcIdBatch ], __METHOD__ );
 183                         if ( count( $rcIdBatches ) > 1 ) {
 184                                 $lbFactory->commitAndWaitForReplication(
 185                                         __METHOD__, $this->ticket, [ 'domain' => $dbw->getDomainID() ]
 186                                 );
 187                         }
 188                 }
 189
 190                 // Commit and release the lock (if set)
 191                 ScopedCallback::consume( $scopedLock );
 192         }
 193
 194         private function batchDeleteByPK( $table, array $conds, array $pk, $bSize ) {
 195                 $services = MediaWikiServices::getInstance();
 196                 $lbFactory = $services->getDBLoadBalancerFactory();
 197                 $dbw = $this->getDB(); // convenience
 198
 199                 $res = $dbw->select( $table, $pk, $conds, __METHOD__ );
 200
 201                 $pkDeleteConds = [];
 202                 foreach ( $res as $row ) {
 203                         $pkDeleteConds[] = $dbw->makeList( (array)$row, LIST_AND );
 204                         if ( count( $pkDeleteConds ) >= $bSize ) {
 205                                 $dbw->delete( $table, $dbw->makeList( $pkDeleteConds, LIST_OR ), __METHOD__ );
 206                                 $lbFactory->commitAndWaitForReplication(
 207                                         __METHOD__, $this->ticket, [ 'domain' => $dbw->getDomainID() ]
 208                                 );
 209                                 $pkDeleteConds = [];
 210                         }
 211                 }
 212
 213                 if ( $pkDeleteConds ) {
 214                         $dbw->delete( $table, $dbw->makeList( $pkDeleteConds, LIST_OR ), __METHOD__ );
 215                 }
 216         }
 217
 218         protected function getDB() {
 219                 if ( !$this->db ) {
 220                         $this->db = wfGetDB( DB_MASTER );
 221                 }
 222
 223                 return $this->db;
 224         }
 225
 226         public function getAsJobSpecification() {
 227                 return [
 228                         'wiki' => WikiMap::getWikiIdFromDbDomain( $this->getDB()->getDomainID() ),
 229                         'job'  => new JobSpecification(
 230                                 'deleteLinks',
 231                                 [ 'pageId' => $this->pageId, 'timestamp' => $this->timestamp ],
 232                                 [ 'removeDuplicates' => true ],
 233                                 $this->page->getTitle()
 234                         )
 235                 ];
 236         }
 237 }