wikimedia/mediawiki-extensions-Wikibase

<?php

namespace Wikibase\Lib\Store\Sql\Terms;

use Job;
use MediaWiki\Logger\LoggerFactory;
use MediaWiki\MediaWikiServices;
use MediaWiki\Title\Title;

/**
 * A job to cleanup the wbt_* terms table rows when they may not be needed any more.
 * This job currently executes in a single transaction.
 *
 * Callers can choose to supply a single termInLang id to clean per job or multiple.
 * Supplying multiple ids will naturally mean the Job and the transaction take longer
 * and therefor locks will also be held for a longer period of time possibly causing lock contention.
 * This started to show on wikidata.org in https://phabricator.wikimedia.org/T246898
 * and thus the default was switched for create a single job per termInLang id.
 * For smaller Wikibase installs with a lower edit rate it might make sense to instead optimize
 * for fewer jobs, where lock contention is less of an issue.
 *
 * @todo Execute the cleanup of each table in its own transaction to further reduce lock contention
 *
 * @see @ref docs_storage_terms
 * @author Addshore
 * @license GPL-2.0-or-later
 */
class CleanTermsIfUnusedJob extends Job {

    /** @var TermStoreCleaner */
    private $termInLangIdsCleaner;

    public const JOB_NAME = 'CleanTermsIfUnused';
    public const TERM_IN_LANG_IDS = 'termInLangIds';

    /**
     * @param Title $unused But required due to the code in Job::factory currently.
     * @param array $params
     * @return CleanTermsIfUnusedJob
     */
    public static function getJobSpecification( Title $unused, array $params ): CleanTermsIfUnusedJob {
        return self::getJobSpecificationNoTitle( $params );
    }

    public static function getJobSpecificationNoTitle( array $params ): CleanTermsIfUnusedJob {
        $repoDomainDb = MediaWikiServices::getInstance()
            ->get( 'WikibaseRepo.RepoDomainDbFactory' )
            ->newRepoDb();

        $logger = LoggerFactory::getInstance( 'Wikibase' );
        $innerTermStoreCleaner = new DatabaseInnerTermStoreCleaner( $logger );
        $cleaner = new DatabaseUsageCheckingTermStoreCleaner( $repoDomainDb, $innerTermStoreCleaner );
        return new self( $cleaner, $params );
    }

    public function __construct( TermStoreCleaner $cleaner, $params ) {
        parent::__construct( self::JOB_NAME, $params );
        $this->termInLangIdsCleaner = $cleaner;
    }

    /**
     * Of the given term in lang IDs, delete those that are not used by any other items or properties.
     *
     * @return bool
     */
    public function run() {
        $termInLangIds = $this->params[self::TERM_IN_LANG_IDS];
        $this->termInLangIdsCleaner->cleanTermInLangIds( $termInLangIds );
        return true;
    }
}