wikimedia / mediawiki

maintenance/populateRevisionLength.php

<?php

For compatibility and reusability of your code, PSR1 recommends that a file should introduce either new symbols (like classes, functions, etc.) or have side-effects (like outputting something, or including other files), but not both at the same time. The first symbol is defined on line 33 and the first side effect is on line 24.

/**
 * Populates the rev_len and ar_len fields when they are NULL.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 * http://www.gnu.org/copyleft/gpl.html
 *
 * @file
 * @ingroup Maintenance
 */

require_once __DIR__ . '/Maintenance.php';

/**
 * Maintenance script that populates the rev_len and ar_len fields when they are NULL.
 * This is the case for all revisions created before MW 1.10, as well as those affected
 * by T18748 (MW 1.10-1.13) and those affected by T135414 (MW 1.21-1.24).
 *
 * @ingroup Maintenance
 */
class PopulateRevisionLength extends LoggedUpdateMaintenance {
	public function __construct() {
		parent::__construct();
		$this->addDescription( 'Populates the rev_len and ar_len fields' );
		$this->setBatchSize( 200 );
	}

	protected function getUpdateKey() {
		return 'populate rev_len and ar_len';
	}

	public function doDBUpdates() {
		$dbw = $this->getDB( DB_MASTER );
		if ( !$dbw->tableExists( 'revision' ) ) {
			$this->error( "revision table does not exist", true );
		} elseif ( !$dbw->tableExists( 'archive' ) ) {
			$this->error( "archive table does not exist", true );
		} elseif ( !$dbw->fieldExists( 'revision', 'rev_len', __METHOD__ ) ) {
			$this->output( "rev_len column does not exist\n\n", true );

			return false;
		}

		$this->output( "Populating rev_len column\n" );
		$rev = $this->doLenUpdates( 'revision', 'rev_id', 'rev', Revision::selectFields() );

		$this->output( "Populating ar_len column\n" );
		$ar = $this->doLenUpdates( 'archive', 'ar_id', 'ar', Revision::selectArchiveFields() );

		$this->output( "rev_len and ar_len population complete "
			. "[$rev revision rows, $ar archive rows].\n" );

		return true;
	}

	/**
	 * @param string $table
	 * @param string $idCol
	 * @param string $prefix
	 * @param array $fields
	 * @return int
	 */
	protected function doLenUpdates( $table, $idCol, $prefix, $fields ) {
		$dbr = $this->getDB( DB_REPLICA );
		$dbw = $this->getDB( DB_MASTER );
		$start = $dbw->selectField( $table, "MIN($idCol)", false, __METHOD__ );
		$end = $dbw->selectField( $table, "MAX($idCol)", false, __METHOD__ );
		if ( !$start || !$end ) {
			$this->output( "...$table table seems to be empty.\n" );

			return 0;
		}

		# Do remaining chunks
		$blockStart = intval( $start );
		$blockEnd = intval( $start ) + $this->mBatchSize - 1;
		$count = 0;

		while ( $blockStart <= $end ) {
			$this->output( "...doing $idCol from $blockStart to $blockEnd\n" );
			$res = $dbr->select(
				$table,
				$fields,
				[
					"$idCol >= $blockStart",
					"$idCol <= $blockEnd",
					"{$prefix}_len IS NULL"
				],
				__METHOD__
			);

			if ( $res->numRows() > 0 ) {
				$this->beginTransaction( $dbw, __METHOD__ );
				# Go through and update rev_len from these rows.
				foreach ( $res as $row ) {
					if ( $this->upgradeRow( $row, $table, $idCol, $prefix ) ) {
						$count++;
					}
				}
				$this->commitTransaction( $dbw, __METHOD__ );
			}

			$blockStart += $this->mBatchSize;
			$blockEnd += $this->mBatchSize;
			wfWaitForSlaves();
		}

		return $count;
	}

	/**
	 * @param stdClass $row
	 * @param string $table
	 * @param string $idCol
	 * @param string $prefix
	 * @return bool
	 */
	protected function upgradeRow( $row, $table, $idCol, $prefix ) {
		$dbw = $this->getDB( DB_MASTER );

		$rev = ( $table === 'archive' )
			? Revision::newFromArchiveRow( $row )
			: new Revision( $row );

		$content = $rev->getContent();
		if ( !$content ) {
			# This should not happen, but sometimes does (bug 20757)
			$id = $row->$idCol;
			$this->output( "Content of $table $id unavailable!\n" );

			return false;
		}

		# Update the row...
		$dbw->update( $table,
			[ "{$prefix}_len" => $content->getSize() ],
			[ $idCol => $row->$idCol ],
			__METHOD__
		);

		return true;
	}
}

$maintClass = "PopulateRevisionLength";
require_once RUN_MAINTENANCE_IF_MAIN;