3 * Updater for link tracking tables after a page edit.
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
22 use MediaWiki\MediaWikiServices
;
23 use Wikimedia\Rdbms\LBFactory
;
26 * Job to add recent change entries mentioning category membership changes
28 * This allows users to easily scan categories for recent page membership changes
32 * - revTimestamp : timestamp of the triggering revision
34 * Category changes will be mentioned for revisions at/after the timestamp for this page
38 class CategoryMembershipChangeJob
extends Job
{
42 const ENQUEUE_FUDGE_SEC
= 60;
50 * @param Title $title The title of the page for which to update category emmbership.
51 * @param string $revisionTimestamp The timestamp of the new revision that triggered the job.
52 * @return JobSpecification
54 public static function newSpec( Title
$title, $revisionTimestamp ) {
55 return new JobSpecification(
56 'categoryMembershipChange',
58 'pageId' => $title->getArticleID(),
59 'revTimestamp' => $revisionTimestamp,
67 * Constructor for use by the Job Queue infrastructure.
68 * @note Don't call this when queueing a new instance, use newSpec() instead.
70 public function __construct( ParserCache
$parserCache, Title
$title, array $params ) {
71 parent
::__construct( 'categoryMembershipChange', $title, $params );
72 // Only need one job per page. Note that ENQUEUE_FUDGE_SEC handles races where an
73 // older revision job gets inserted while the newer revision job is de-duplicated.
74 $this->removeDuplicates
= true;
75 $this->parserCache
= $parserCache;
78 public function run() {
79 $lbFactory = MediaWikiServices
::getInstance()->getDBLoadBalancerFactory();
80 $lb = $lbFactory->getMainLB();
81 $dbw = $lb->getConnection( DB_MASTER
);
83 $this->ticket
= $lbFactory->getEmptyTransactionTicket( __METHOD__
);
85 $page = WikiPage
::newFromID( $this->params
['pageId'], WikiPage
::READ_LATEST
);
87 $this->setLastError( "Could not find page #{$this->params['pageId']}" );
88 return false; // deleted?
91 // Cut down on the time spent in safeWaitForMasterPos() in the critical section
92 $dbr = $lb->getConnection( DB_REPLICA
, [ 'recentchanges' ] );
93 if ( !$lb->safeWaitForMasterPos( $dbr ) ) {
94 $this->setLastError( "Timed out while pre-waiting for replica DB to catch up" );
98 // Use a named lock so that jobs for this page see each others' changes
99 $lockKey = "CategoryMembershipUpdates:{$page->getId()}";
100 $scopedLock = $dbw->getScopedLockAndFlush( $lockKey, __METHOD__
, 3 );
101 if ( !$scopedLock ) {
102 $this->setLastError( "Could not acquire lock '$lockKey'" );
106 // Wait till replica DB is caught up so that jobs for this page see each others' changes
107 if ( !$lb->safeWaitForMasterPos( $dbr ) ) {
108 $this->setLastError( "Timed out while waiting for replica DB to catch up" );
111 // Clear any stale REPEATABLE-READ snapshot
112 $dbr->flushSnapshot( __METHOD__
);
114 $cutoffUnix = wfTimestamp( TS_UNIX
, $this->params
['revTimestamp'] );
115 // Using ENQUEUE_FUDGE_SEC handles jobs inserted out of revision order due to the delay
116 // between COMMIT and actual enqueueing of the CategoryMembershipChangeJob job.
117 $cutoffUnix -= self
::ENQUEUE_FUDGE_SEC
;
119 // Get the newest page revision that has a SRC_CATEGORIZE row.
120 // Assume that category changes before it were already handled.
121 $row = $dbr->selectRow(
123 [ 'rev_timestamp', 'rev_id' ],
125 'rev_page' => $page->getId(),
126 'rev_timestamp >= ' . $dbr->addQuotes( $dbr->timestamp( $cutoffUnix ) ),
127 'EXISTS (' . $dbr->selectSQLText(
131 'rc_this_oldid = rev_id',
132 'rc_source' => RecentChange
::SRC_CATEGORIZE
,
133 // Allow rc_cur_id or rc_timestamp index usage
134 'rc_cur_id = rev_page',
135 'rc_timestamp = rev_timestamp'
140 [ 'ORDER BY' => 'rev_timestamp DESC, rev_id DESC' ]
142 // Only consider revisions newer than any such revision
144 $cutoffUnix = wfTimestamp( TS_UNIX
, $row->rev_timestamp
);
145 $lastRevId = (int)$row->rev_id
;
150 // Find revisions to this page made around and after this revision which lack category
151 // notifications in recent changes. This lets jobs pick up were the last one left off.
152 $encCutoff = $dbr->addQuotes( $dbr->timestamp( $cutoffUnix ) );
153 $revQuery = Revision
::getQueryInfo();
158 'rev_page' => $page->getId(),
159 "rev_timestamp > $encCutoff" .
160 " OR (rev_timestamp = $encCutoff AND rev_id > $lastRevId)"
163 [ 'ORDER BY' => 'rev_timestamp ASC, rev_id ASC' ],
167 // Apply all category updates in revision timestamp order
168 foreach ( $res as $row ) {
169 $this->notifyUpdatesForRevision( $lbFactory, $page, Revision
::newFromRow( $row ) );
176 * @param LBFactory $lbFactory
177 * @param WikiPage $page
178 * @param Revision $newRev
179 * @throws MWException
181 protected function notifyUpdatesForRevision(
182 LBFactory
$lbFactory, WikiPage
$page, Revision
$newRev
184 $config = RequestContext
::getMain()->getConfig();
185 $title = $page->getTitle();
187 // Get the new revision
188 if ( !$newRev->getContent() ) {
192 // Get the prior revision (the same for null edits)
193 if ( $newRev->getParentId() ) {
194 $oldRev = Revision
::newFromId( $newRev->getParentId(), Revision
::READ_LATEST
);
195 if ( !$oldRev->getContent() ) {
202 // Parse the new revision and get the categories
203 $categoryChanges = $this->getExplicitCategoriesChanges( $page, $newRev, $oldRev );
204 list( $categoryInserts, $categoryDeletes ) = $categoryChanges;
205 if ( !$categoryInserts && !$categoryDeletes ) {
206 return; // nothing to do
209 $catMembChange = new CategoryMembershipChange( $title, $newRev );
210 $catMembChange->checkTemplateLinks();
212 $batchSize = $config->get( 'UpdateRowsPerQuery' );
215 foreach ( $categoryInserts as $categoryName ) {
216 $categoryTitle = Title
::makeTitle( NS_CATEGORY
, $categoryName );
217 $catMembChange->triggerCategoryAddedNotification( $categoryTitle );
218 if ( $insertCount++
&& ( $insertCount %
$batchSize ) == 0 ) {
219 $lbFactory->commitAndWaitForReplication( __METHOD__
, $this->ticket
);
223 foreach ( $categoryDeletes as $categoryName ) {
224 $categoryTitle = Title
::makeTitle( NS_CATEGORY
, $categoryName );
225 $catMembChange->triggerCategoryRemovedNotification( $categoryTitle );
226 if ( $insertCount++
&& ( $insertCount++ %
$batchSize ) == 0 ) {
227 $lbFactory->commitAndWaitForReplication( __METHOD__
, $this->ticket
);
232 private function getExplicitCategoriesChanges(
233 WikiPage
$page, Revision
$newRev, Revision
$oldRev = null
235 // Inject the same timestamp for both revision parses to avoid seeing category changes
236 // due to time-based parser functions. Inject the same page title for the parses too.
237 // Note that REPEATABLE-READ makes template/file pages appear unchanged between parses.
238 $parseTimestamp = $newRev->getTimestamp();
239 // Parse the old rev and get the categories. Do not use link tables as that
240 // assumes these updates are perfectly FIFO and that link tables are always
241 // up to date, neither of which are true.
242 $oldCategories = $oldRev
243 ?
$this->getCategoriesAtRev( $page, $oldRev, $parseTimestamp )
245 // Parse the new revision and get the categories
246 $newCategories = $this->getCategoriesAtRev( $page, $newRev, $parseTimestamp );
248 $categoryInserts = array_values( array_diff( $newCategories, $oldCategories ) );
249 $categoryDeletes = array_values( array_diff( $oldCategories, $newCategories ) );
251 return [ $categoryInserts, $categoryDeletes ];
255 * @param WikiPage $page
256 * @param Revision $rev
257 * @param string $parseTimestamp TS_MW
259 * @return string[] category names
261 private function getCategoriesAtRev( WikiPage
$page, Revision
$rev, $parseTimestamp ) {
262 $renderer = MediaWikiServices
::getInstance()->getRevisionRenderer();
263 $options = $page->makeParserOptions( 'canonical' );
264 $options->setTimestamp( $parseTimestamp );
266 $output = $rev->isCurrent() ?
$this->parserCache
->get( $page, $options ) : null;
268 if ( !$output ||
$output->getCacheRevisionId() !== $rev->getId() ) {
269 $output = $renderer->getRenderedRevision( $rev->getRevisionRecord(), $options )
270 ->getRevisionParserOutput();
273 // array keys will cast numeric category names to ints
274 // so we need to cast them back to strings to avoid breaking things!
275 return array_map( 'strval', array_keys( $output->getCategories() ) );
278 public function getDeduplicationInfo() {
279 $info = parent
::getDeduplicationInfo();
280 unset( $info['params']['revTimestamp'] ); // first job wins