populateArchiveRevId.php

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<?php
use MediaWiki\MediaWikiServices;
use Wikimedia\Rdbms\DBQueryError;
use Wikimedia\Rdbms\IDatabase;
 
require_once __DIR__ . '/Maintenance.php';
 
class PopulateArchiveRevId extends LoggedUpdateMaintenance {
 
    private static $dummyRev = null;
 
    public function __construct() {
        parent::__construct();
        $this->addDescription( 'Populate ar_rev_id in pre-1.5 rows' );
        $this->setBatchSize( 100 );
    }
 
    public static function isNewInstall( IDatabase $dbw ) {
        return $dbw->selectRowCount( 'archive', '*', [], __METHOD__ ) === 0 &&
            $dbw->selectRowCount( 'revision', '*', [], __METHOD__ ) === 1;
    }
 
    protected function getUpdateKey() {
        return __CLASS__;
    }
 
    protected function doDBUpdates() {
        $this->output( "Populating ar_rev_id...\n" );
        $dbw = $this->getDB( DB_MASTER );
        self::checkMysqlAutoIncrementBug( $dbw );
 
        // Quick exit if there are no rows needing updates.
        $any = $dbw->selectField(
            'archive',
            'ar_id',
            [ 'ar_rev_id' => null ],
            __METHOD__
        );
        if ( !$any ) {
            $this->output( "Completed ar_rev_id population, 0 rows updated.\n" );
            return true;
        }
 
        $lbFactory = MediaWikiServices::getInstance()->getDBLoadBalancerFactory();
        $count = 0;
        while ( true ) {
            $lbFactory->waitForReplication();
 
            $arIds = $dbw->selectFieldValues(
                'archive',
                'ar_id',
                [ 'ar_rev_id' => null ],
                __METHOD__,
                [ 'LIMIT' => $this->getBatchSize(), 'ORDER BY' => [ 'ar_id' ] ]
            );
            if ( !$arIds ) {
                $this->output( "Completed ar_rev_id population, $count rows updated.\n" );
                return true;
            }
 
            $count += self::reassignArRevIds( $dbw, $arIds, [ 'ar_rev_id' => null ] );
 
            $min = min( $arIds );
            $max = max( $arIds );
            $this->output( " ... $min-$max\n" );
        }
    }
 
    public static function checkMysqlAutoIncrementBug( IDatabase $dbw ) {
        if ( $dbw->getType() !== 'mysql' ) {
            return;
        }
 
        if ( !self::$dummyRev ) {
            self::$dummyRev = self::makeDummyRevisionRow( $dbw );
        }
 
        $ok = false;
        while ( !$ok ) {
            try {
                $dbw->doAtomicSection( __METHOD__, function ( IDatabase $dbw, $fname ) {
                    $dbw->insert( 'revision', self::$dummyRev, $fname );
                    $id = $dbw->insertId();
                    $toDelete = [ $id ];
 
                    $maxId = max(
                        (int)$dbw->selectField( 'archive', 'MAX(ar_rev_id)', [], $fname ),
                        (int)$dbw->selectField( 'slots', 'MAX(slot_revision_id)', [], $fname )
                    );
                    if ( $id <= $maxId ) {
                        $dbw->insert( 'revision', [ 'rev_id' => $maxId + 1 ] + self::$dummyRev, $fname );
                        $toDelete[] = $maxId + 1;
                    }
 
                    $dbw->delete( 'revision', [ 'rev_id' => $toDelete ], $fname );
                } );
                $ok = true;
            } catch ( DBQueryError $e ) {
                if ( $e->errno != 1062 ) {
                    // 1062 is "duplicate entry", ignore it and retry
                    throw $e;
                }
            }
        }
    }
 
    public static function reassignArRevIds( IDatabase $dbw, array $arIds, array $conds = [] ) {
        if ( !self::$dummyRev ) {
            self::$dummyRev = self::makeDummyRevisionRow( $dbw );
        }
 
        $updates = $dbw->doAtomicSection( __METHOD__, function ( IDatabase $dbw, $fname ) use ( $arIds ) {
            // Create new rev_ids by inserting dummy rows into revision and then deleting them.
            $dbw->insert( 'revision', array_fill( 0, count( $arIds ), self::$dummyRev ), $fname );
            $revIds = $dbw->selectFieldValues(
                'revision',
                'rev_id',
                // @phan-suppress-next-line PhanTypeArraySuspiciousNullable
                [ 'rev_timestamp' => self::$dummyRev['rev_timestamp'] ],
                $fname
            );
            if ( !is_array( $revIds ) ) {
                throw new UnexpectedValueException( 'Failed to insert dummy revisions' );
            }
            if ( count( $revIds ) !== count( $arIds ) ) {
                throw new UnexpectedValueException(
                    'Tried to insert ' . count( $arIds ) . ' dummy revisions, but found '
                    . count( $revIds ) . ' matching rows.'
                );
            }
            $dbw->delete( 'revision', [ 'rev_id' => $revIds ], $fname );
 
            return array_combine( $arIds, $revIds );
        } );
 
        $count = 0;
        foreach ( $updates as $arId => $revId ) {
            $dbw->update(
                'archive',
                [ 'ar_rev_id' => $revId ],
                [ 'ar_id' => $arId ] + $conds,
                __METHOD__
            );
            $count += $dbw->affectedRows();
        }
        return $count;
    }
 
    private static function makeDummyRevisionRow( IDatabase $dbw ) {
        $ts = $dbw->timestamp( '11111111111111' );
        $rev = null;
 
        $mainPage = Title::newMainPage();
        $pageId = $mainPage ? $mainPage->getArticleID() : null;
        if ( $pageId ) {
            $rev = $dbw->selectRow(
                'revision',
                '*',
                [ 'rev_page' => $pageId ],
                __METHOD__,
                [ 'ORDER BY' => 'rev_timestamp ASC' ]
            );
        }
 
        if ( !$rev ) {
            // No main page? Let's see if there are any revisions at all
            $rev = $dbw->selectRow(
                'revision',
                '*',
                [],
                __METHOD__,
                [ 'ORDER BY' => 'rev_timestamp ASC' ]
            );
        }
        if ( !$rev ) {
            // Since no revisions are available to copy, generate a dummy
            // revision to a dummy page, then rollback the commit
            wfDebug( __METHOD__ . ": No revisions are available to copy" );
 
            $dbw->begin( __METHOD__ );
 
            // Make a title and revision and insert them
            $title = Title::newFromText( "PopulateArchiveRevId_4b05b46a81e29" );
            $page = WikiPage::factory( $title );
            $updater = $page->newPageUpdater(
                User::newSystemUser( 'Maintenance script', [ 'steal' => true ] )
            );
            $updater->setContent(
                'main',
                ContentHandler::makeContent( "Content for dummy rev", $title )
            );
            $updater->saveRevision(
                CommentStoreComment::newUnsavedComment( 'dummy rev summary' ),
                EDIT_NEW | EDIT_SUPPRESS_RC
            );
 
            // get the revision row just inserted
            $rev = $dbw->selectRow(
                'revision',
                '*',
                [],
                __METHOD__,
                [ 'ORDER BY' => 'rev_timestamp ASC' ]
            );
 
            $dbw->rollback( __METHOD__ );
        }
        if ( !$rev ) {
            // This should never happen.
            throw new UnexpectedValueException(
                'No revisions are available to copy, and one couldn\'t be created'
            );
        }
 
        unset( $rev->rev_id );
        $rev = (array)$rev;
        $rev['rev_timestamp'] = $ts;
        if ( isset( $rev['rev_user'] ) ) {
            $rev['rev_user'] = 0;
            $rev['rev_user_text'] = '0.0.0.0';
        }
        if ( isset( $rev['rev_comment'] ) ) {
            $rev['rev_comment'] = 'Dummy row';
        }
 
        $any = $dbw->selectField(
            'revision',
            'rev_id',
            [ 'rev_timestamp' => $ts ],
            __METHOD__
        );
        if ( $any ) {
            throw new UnexpectedValueException( "... Why does your database contain a revision dated $ts?" );
        }
 
        return $rev;
    }
}
 
$maintClass = PopulateArchiveRevId::class;
require_once RUN_MAINTENANCE_IF_MAIN;