wikimedia / mediawiki

maintenance/convertLinks.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 34 and the first side effect is on line 24.

/**
 * Convert from the old links schema (string->ID) to the new schema (ID->ID).
 *
 * 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 to convert from the old links schema (string->ID)
 * to the new schema (ID->ID).
 *
 * The wiki should be put into read-only mode while this script executes.
 *
 * @ingroup Maintenance
 */
class ConvertLinks extends Maintenance {
	private $logPerformance;

	public function __construct() {
		parent::__construct();
		$this->addDescription(
			'Convert from the old links schema (string->ID) to the new schema (ID->ID). '
				. 'The wiki should be put into read-only mode while this script executes' );

		$this->addArg( 'logperformance', "Log performance to perfLogFilename.", false );
		$this->addArg(
			'perfLogFilename',
			"Filename where performance is logged if --logperformance was set "
				. "(defaults to 'convLinksPerf.txt').",
			false
		);
		$this->addArg(
			'keep-links-table',
			"Don't overwrite the old links table with the new one, leave the new table at links_temp.",
			false
		);
		$this->addArg(
			'nokeys',
			/* (What about InnoDB?) */
			"Don't create keys, and so allow duplicates in the new links table.\n"
				. "This gives a huge speed improvement for very large links tables which are MyISAM.",
			false
		);
	}

	public function getDbType() {
		return Maintenance::DB_ADMIN;
	}

	public function execute() {
		$dbw = $this->getDB( DB_MASTER );

		$type = $dbw->getType();
		if ( $type != 'mysql' ) {
			$this->output( "Link table conversion not necessary for $type\n" );

			return;
		}

		global $wgContLang;

		# counters etc
		$numBadLinks = $curRowsRead = 0;

		# total tuples INSERTed into links_temp
		$totalTuplesInserted = 0;

		# whether or not to give progress reports while reading IDs from cur table
		$reportCurReadProgress = true;

		# number of rows between progress reports
		$curReadReportInterval = 1000;

		# whether or not to give progress reports during conversion
		$reportLinksConvProgress = true;

		# number of rows per INSERT
		$linksConvInsertInterval = 1000;

		$initialRowOffset = 0;

		# not used yet; highest row number from links table to process
		# $finalRowOffset = 0;

		$overwriteLinksTable = !$this->hasOption( 'keep-links-table' );
		$noKeys = $this->hasOption( 'noKeys' );
		$this->logPerformance = $this->hasOption( 'logperformance' );
		$perfLogFilename = $this->getArg( 'perfLogFilename', "convLinksPerf.txt" );

		# --------------------------------------------------------------------

		list( $cur, $links, $links_temp, $links_backup ) =
			$dbw->tableNamesN( 'cur', 'links', 'links_temp', 'links_backup' );

		if ( $dbw->tableExists( 'pagelinks' ) ) {
			$this->output( "...have pagelinks; skipping old links table updates\n" );

			return;
		}

		$res = $dbw->query( "SELECT l_from FROM $links LIMIT 1" );
		if ( $dbw->fieldType( $res, 0 ) == "int" ) {
			$this->output( "Schema already converted\n" );

			return;
		}

		$res = $dbw->query( "SELECT COUNT(*) AS count FROM $links" );
		$row = $dbw->fetchObject( $res );
		$numRows = $row->count;
		$dbw->freeResult( $res );

		if ( $numRows == 0 ) {
			$this->output( "Updating schema (no rows to convert)...\n" );
			$this->createTempTable();
		} else {
			$fh = false;
			if ( $this->logPerformance ) {
				$fh = fopen( $perfLogFilename, "w" );
				if ( !$fh ) {
					$this->error( "Couldn't open $perfLogFilename" );
					$this->logPerformance = false;
				}
			}
			$baseTime = $startTime = microtime( true );
			# Create a title -> cur_id map
			$this->output( "Loading IDs from $cur table...\n" );
			$this->performanceLog( $fh, "Reading $numRows rows from cur table...\n" );
			$this->performanceLog( $fh, "rows read vs seconds elapsed:\n" );

			$dbw->bufferResults( false );
			$res = $dbw->query( "SELECT cur_namespace,cur_title,cur_id FROM $cur" );
			$ids = [];

			foreach ( $res as $row ) {
				$title = $row->cur_title;
				if ( $row->cur_namespace ) {
					$title = $wgContLang->getNsText( $row->cur_namespace ) . ":$title";
				}
				$ids[$title] = $row->cur_id;
				$curRowsRead++;
				if ( $reportCurReadProgress ) {
					if ( ( $curRowsRead % $curReadReportInterval ) == 0 ) {
						$this->performanceLog(
							$fh,
							$curRowsRead . " " . ( microtime( true ) - $baseTime ) . "\n"
						);
						$this->output( "\t$curRowsRead rows of $cur table read.\n" );
					}
				}
			}
			$dbw->freeResult( $res );
			$dbw->bufferResults( true );
			$this->output( "Finished loading IDs.\n\n" );
			$this->performanceLog(
				$fh,
				"Took " . ( microtime( true ) - $baseTime ) . " seconds to load IDs.\n\n"
			);

			# --------------------------------------------------------------------

			# Now, step through the links table (in chunks of $linksConvInsertInterval rows),
			# convert, and write to the new table.
			$this->createTempTable();
			$this->performanceLog( $fh, "Resetting timer.\n\n" );
			$baseTime = microtime( true );
			$this->output( "Processing $numRows rows from $links table...\n" );
			$this->performanceLog( $fh, "Processing $numRows rows from $links table...\n" );
			$this->performanceLog( $fh, "rows inserted vs seconds elapsed:\n" );

			for ( $rowOffset = $initialRowOffset; $rowOffset < $numRows;
				$rowOffset += $linksConvInsertInterval
			) {
				$sqlRead = "SELECT * FROM $links ";
				$sqlRead = $dbw->limitResult( $sqlRead, $linksConvInsertInterval, $rowOffset );
				$res = $dbw->query( $sqlRead );
				if ( $noKeys ) {
					$sqlWrite = [ "INSERT INTO $links_temp (l_from,l_to) VALUES " ];
				} else {
					$sqlWrite = [ "INSERT IGNORE INTO $links_temp (l_from,l_to) VALUES " ];
				}

				$tuplesAdded = 0; # no tuples added to INSERT yet
				foreach ( $res as $row ) {
					$fromTitle = $row->l_from;
					if ( array_key_exists( $fromTitle, $ids ) ) { # valid title
						$from = $ids[$fromTitle];
						$to = $row->l_to;
						if ( $tuplesAdded != 0 ) {
							$sqlWrite[] = ",";
						}
						$sqlWrite[] = "($from,$to)";
						$tuplesAdded++;
					} else { # invalid title
						$numBadLinks++;
					}
				}
				$dbw->freeResult( $res );
				# $this->output( "rowOffset: $rowOffset\ttuplesAdded: "
				# 	. "$tuplesAdded\tnumBadLinks: $numBadLinks\n" );
				if ( $tuplesAdded != 0 ) {
					if ( $reportLinksConvProgress ) {
						$this->output( "Inserting $tuplesAdded tuples into $links_temp..." );
					}
					$dbw->query( implode( "", $sqlWrite ) );
					$totalTuplesInserted += $tuplesAdded;
					if ( $reportLinksConvProgress ) {
						$this->output( " done. Total $totalTuplesInserted tuples inserted.\n" );
						$this->performanceLog(
							$fh,
							$totalTuplesInserted . " " . ( microtime( true ) - $baseTime ) . "\n"
						);
					}
				}
			}
			$this->output( "$totalTuplesInserted valid titles and "
				. "$numBadLinks invalid titles were processed.\n\n" );
			$this->performanceLog(
				$fh,
				"$totalTuplesInserted valid titles and $numBadLinks invalid titles were processed.\n"
			);
			$this->performanceLog(
				$fh,
				"Total execution time: " . ( microtime( true ) - $startTime ) . " seconds.\n"
			);
			if ( $this->logPerformance ) {
				fclose( $fh );
			}
		}
		# --------------------------------------------------------------------

		if ( $overwriteLinksTable ) {
			# Check for existing links_backup, and delete it if it exists.
			$this->output( "Dropping backup links table if it exists..." );
			$dbw->query( "DROP TABLE IF EXISTS $links_backup", __METHOD__ );
			$this->output( " done.\n" );

			# Swap in the new table, and move old links table to links_backup
			$this->output( "Swapping tables '$links' to '$links_backup'; '$links_temp' to '$links'..." );
			$dbw->query( "RENAME TABLE links TO $links_backup, $links_temp TO $links", __METHOD__ );
			$this->output( " done.\n\n" );

			$this->output( "Conversion complete. The old table remains at $links_backup;\n" );
			$this->output( "delete at your leisure.\n" );
		} else {
			$this->output( "Conversion complete.  The converted table is at $links_temp;\n" );
			$this->output( "the original links table is unchanged.\n" );
		}
	}

	private function createTempTable() {
		$dbConn = $this->getDB( DB_MASTER );

		if ( !( $dbConn->isOpen() ) ) {
			$this->output( "Opening connection to database failed.\n" );

			return;
		}
		$links_temp = $dbConn->tableName( 'links_temp' );

		$this->output( "Dropping temporary links table if it exists..." );
		$dbConn->query( "DROP TABLE IF EXISTS $links_temp" );
		$this->output( " done.\n" );

		$this->output( "Creating temporary links table..." );
		if ( $this->hasOption( 'noKeys' ) ) {
			$dbConn->query( "CREATE TABLE $links_temp ( " .
				"l_from int(8) unsigned NOT NULL default '0', " .
				"l_to int(8) unsigned NOT NULL default '0')" );
		} else {
			$dbConn->query( "CREATE TABLE $links_temp ( " .
				"l_from int(8) unsigned NOT NULL default '0', " .
				"l_to int(8) unsigned NOT NULL default '0', " .
				"UNIQUE KEY l_from(l_from,l_to), " .
				"KEY (l_to))" );
		}
		$this->output( " done.\n\n" );
	}

	private function performanceLog( $fh, $text ) {
		if ( $this->logPerformance ) {
			fwrite( $fh, $text );
		}
	}
}

$maintClass = "ConvertLinks";
require_once RUN_MAINTENANCE_IF_MAIN;