runBatchedQuery.php

Go to the documentation of this file.

<?php
// @codeCoverageIgnoreStart
require_once __DIR__ . '/Maintenance.php';
// @codeCoverageIgnoreEnd
 
use MediaWiki\Maintenance\Maintenance;
use MediaWiki\Utils\BatchRowIterator;
 
class RunBatchedQuery extends Maintenance {
    public function __construct() {
        parent::__construct();
        $this->addDescription(
            "Run an update query on all rows of a table. " .
            "Waits for replicas at appropriate intervals." );
        $this->addOption( 'table', 'The table name', true, true );
        $this->addOption( 'set', 'The SET clause', true, true );
        $this->addOption( 'where', 'The WHERE clause', false, true );
        $this->addOption( 'key', 'A column name, the values of which are unique', true, true );
        $this->addOption( 'batch-size', 'The batch size (default 1000)', false, true );
        $this->addOption( 'db', 'The database name, or omit to use the current wiki.', false, true );
    }
 
    public function execute() {
        $table = $this->getOption( 'table' );
        $key = $this->getOption( 'key' );
        $set = $this->getOption( 'set' );
        $where = $this->getOption( 'where', null );
        $where = $where === null ? [] : [ $where ];
        $batchSize = $this->getOption( 'batch-size', 1000 );
 
        $dbName = $this->getOption( 'db', null );
        if ( $dbName === null ) {
            $dbw = $this->getPrimaryDB();
        } else {
            $dbw = $this->getServiceContainer()->getConnectionProvider()->getPrimaryDatabase( $dbName );
        }
 
        $queryBuilder = $dbw->newSelectQueryBuilder()
            ->select( $key )
            ->from( $table )
            ->where( $where )
            ->caller( __METHOD__ );
 
        $iterator = new BatchRowIterator( $dbw, $queryBuilder, $key, $batchSize );
        foreach ( $iterator as $n => $batch ) {
            $this->output( "Batch $n: " );
 
            // Note that the update conditions do not rely on the atomicity of the
            // SELECT query in order to guarantee that all rows are updated. The
            // results of the SELECT are merely a partitioning hint. Simultaneous
            // updates merely result in the wrong number of rows being updated
            // in a batch.
 
            $firstRow = reset( $batch );
            $lastRow = end( $batch );
 
            $dbw->newUpdateQueryBuilder()
                ->table( $table )
                ->set( $set )
                ->where( $where )
                ->andWhere( $dbw->expr( $key, '>=', $firstRow->$key ) )
                ->andWhere( $dbw->expr( $key, '<=', $lastRow->$key ) )
                ->caller( __METHOD__ )
                ->execute();
 
            $affected = $dbw->affectedRows();
            $this->output( "$affected rows affected\n" );
            $this->waitForReplication();
        }
    }
 
    public function getDbType() {
        return Maintenance::DB_ADMIN;
    }
}
 
// @codeCoverageIgnoreStart
$maintClass = RunBatchedQuery::class;
require_once RUN_MAINTENANCE_IF_MAIN;
// @codeCoverageIgnoreEnd