migrateArchiveText.php

Go to the documentation of this file.

<?php
use MediaWiki\MainConfigNames;
use MediaWiki\MediaWikiServices;
 
require_once __DIR__ . '/Maintenance.php';
 
class MigrateArchiveText extends LoggedUpdateMaintenance {
    public function __construct() {
        parent::__construct();
        $this->addDescription(
            'Migrates content from pre-1.5 ar_text and ar_flags columns to text storage'
        );
        $this->addOption(
            'replace-missing',
            "For rows with missing or unloadable data, throw away whatever is there and\n"
            . "mark them as \"error\" in the database."
        );
    }
 
    protected function getUpdateKey() {
        return __CLASS__;
    }
 
    protected function doDBUpdates() {
        $replaceMissing = $this->hasOption( 'replace-missing' );
        $defaultExternalStore = $this->getConfig()->get( MainConfigNames::DefaultExternalStore );
        $blobStore = MediaWikiServices::getInstance()
            ->getBlobStoreFactory()
            ->newSqlBlobStore();
        $batchSize = $this->getBatchSize();
 
        $dbr = $this->getDB( DB_REPLICA, [ 'vslow' ] );
        $dbw = $this->getDB( DB_PRIMARY );
        if ( !$dbr->fieldExists( 'archive', 'ar_text', __METHOD__ ) ||
            !$dbw->fieldExists( 'archive', 'ar_text', __METHOD__ )
        ) {
            $this->output( "No ar_text field, so nothing to migrate.\n" );
            return true;
        }
 
        $this->output( "Migrating ar_text to modern storage...\n" );
        $last = 0;
        $count = 0;
        $errors = 0;
        while ( true ) {
            $res = $dbr->select(
                'archive',
                [ 'ar_id', 'ar_text', 'ar_flags' ],
                [
                    'ar_text_id' => null,
                    "ar_id > $last",
                ],
                __METHOD__,
                [ 'LIMIT' => $batchSize, 'ORDER BY' => [ 'ar_id' ] ]
            );
            $numRows = $res->numRows();
 
            foreach ( $res as $row ) {
                $last = $row->ar_id;
 
                // Recompress the text (and store in external storage, if
                // applicable) if it's not already in external storage.
                $arFlags = explode( ',', $row->ar_flags );
                if ( !in_array( 'external', $arFlags, true ) ) {
                    $data = $blobStore->decompressData( $row->ar_text, $arFlags );
                    if ( $data !== false ) {
                        $flags = $blobStore->compressData( $data );
 
                        if ( $defaultExternalStore ) {
                            $data = ExternalStore::insertToDefault( $data );
                            if ( $flags ) {
                                $flags .= ',';
                            }
                            $flags .= 'external';
                        }
                    } elseif ( $replaceMissing ) {
                        $this->error( "Replacing missing data for row ar_id=$row->ar_id" );
                        $data = 'Missing data in migrateArchiveText.php on ' . date( 'c' );
                        $flags = 'error';
                    } else {
                        $this->error( "No data for row ar_id=$row->ar_id" );
                        $errors++;
                        continue;
                    }
                } else {
                    $flags = $row->ar_flags;
                    $data = $row->ar_text;
                }
 
                $this->beginTransaction( $dbw, __METHOD__ );
                $dbw->insert(
                    'text',
                    [ 'old_text' => $data, 'old_flags' => $flags ],
                    __METHOD__
                );
                $id = $dbw->insertId();
                $dbw->update(
                    'archive',
                    [ 'ar_text_id' => $id, 'ar_text' => '', 'ar_flags' => '' ],
                    [ 'ar_id' => $row->ar_id, 'ar_text_id' => null ],
                    __METHOD__
                );
                $count += $dbw->affectedRows();
                $this->commitTransaction( $dbw, __METHOD__ );
            }
 
            if ( $numRows < $batchSize ) {
                // We must have reached the end
                break;
            }
 
            $this->output( "... $last\n" );
            // $this->commitTransaction() already waited for replication; no need to re-wait here
        }
 
        $this->output( "Completed ar_text migration, $count rows updated, $errors missing data.\n" );
        if ( $errors ) {
            $this->output( "Run with --replace-missing to overwrite missing data with an error message.\n" );
        }
 
        return $errors === 0;
    }
}
 
$maintClass = MigrateArchiveText::class;
require_once RUN_MAINTENANCE_IF_MAIN;