populateContentTables.php

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<?php
use MediaWiki\MediaWikiServices;
use MediaWiki\Revision\SlotRecord;
use MediaWiki\Storage\BlobStore;
use MediaWiki\Storage\NameTableStore;
use MediaWiki\Storage\SqlBlobStore;
use Wikimedia\Assert\Assert;
use Wikimedia\Rdbms\IDatabase;
use Wikimedia\Rdbms\IResultWrapper;
 
require_once __DIR__ . '/Maintenance.php';
 
class PopulateContentTables extends Maintenance {
 
    private $dbw;
 
    private $contentModelStore;
 
    private $slotRoleStore;
 
    private $blobStore;
 
    private $mainRoleId;
 
    private $contentRowMap = null;
 
    private $count = 0, $totalCount = 0;
 
    public function __construct() {
        parent::__construct();
 
        $this->addDescription( 'Populate content and slot tables' );
        $this->addOption( 'table', 'revision or archive table, or `all` to populate both', false,
            true );
        $this->addOption( 'reuse-content',
            'Reuse content table rows when the address and model are the same. '
            . 'This will increase the script\'s time and memory usage, perhaps significantly.',
            false, false );
        $this->addOption( 'start-revision', 'The rev_id to start at', false, true );
        $this->addOption( 'start-archive', 'The ar_rev_id to start at', false, true );
        $this->setBatchSize( 500 );
    }
 
    private function initServices() {
        $this->dbw = $this->getDB( DB_MASTER );
        $this->contentModelStore = MediaWikiServices::getInstance()->getContentModelStore();
        $this->slotRoleStore = MediaWikiServices::getInstance()->getSlotRoleStore();
        $this->blobStore = MediaWikiServices::getInstance()->getBlobStore();
 
        // Don't trust the cache for the NameTableStores, in case something went
        // wrong during a previous run (see T224949#5325895).
        $this->contentModelStore->reloadMap();
        $this->slotRoleStore->reloadMap();
        $this->mainRoleId = $this->slotRoleStore->acquireId( SlotRecord::MAIN );
    }
 
    public function execute() {
        $multiContentRevisionSchemaMigrationStage =
            $this->getConfig()->get( 'MultiContentRevisionSchemaMigrationStage' );
 
        $t0 = microtime( true );
 
        if ( ( $multiContentRevisionSchemaMigrationStage & SCHEMA_COMPAT_WRITE_NEW ) === 0 ) {
            $this->writeln(
                '...cannot update while \$wgMultiContentRevisionSchemaMigrationStage '
                . 'does not have the SCHEMA_COMPAT_WRITE_NEW bit set.'
            );
            return false;
        }
 
        $this->initServices();
 
        if ( $this->getOption( 'reuse-content', false ) ) {
            $this->loadContentMap();
        }
 
        foreach ( $this->getTables() as $table ) {
            $this->populateTable( $table );
        }
 
        $elapsed = microtime( true ) - $t0;
        $this->writeln( "Done. Processed $this->totalCount rows in $elapsed seconds" );
        return true;
    }
 
    private function getTables() {
        $table = $this->getOption( 'table', 'all' );
        $validTableOptions = [ 'all', 'revision', 'archive' ];
 
        if ( !in_array( $table, $validTableOptions ) ) {
            $this->fatalError( 'Invalid table. Must be either `revision` or `archive` or `all`' );
        }
 
        if ( $table === 'all' ) {
            $tables = [ 'revision', 'archive' ];
        } else {
            $tables = [ $table ];
        }
 
        return $tables;
    }
 
    private function loadContentMap() {
        $t0 = microtime( true );
        $this->writeln( "Loading existing content table rows..." );
        $this->contentRowMap = [];
        $dbr = $this->getDB( DB_REPLICA );
        $from = false;
        while ( true ) {
            $res = $dbr->select(
                'content',
                [ 'content_id', 'content_address', 'content_model' ],
                $from ? "content_id > $from" : '',
                __METHOD__,
                [ 'ORDER BY' => 'content_id', 'LIMIT' => $this->getBatchSize() ]
            );
            if ( !$res || !$res->numRows() ) {
                break;
            }
            foreach ( $res as $row ) {
                $from = $row->content_id;
                $this->contentRowMap["{$row->content_model}:{$row->content_address}"] = $row->content_id;
            }
        }
        $elapsed = microtime( true ) - $t0;
        $this->writeln( "Loaded " . count( $this->contentRowMap ) . " rows in $elapsed seconds" );
    }
 
    private function populateTable( $table ) {
        $t0 = microtime( true );
        $this->count = 0;
        $this->writeln( "Populating $table..." );
 
        if ( $table === 'revision' ) {
            $idField = 'rev_id';
            $tables = [ 'revision', 'slots', 'page' ];
            $fields = [
                'rev_id',
                'len' => 'rev_len',
                'sha1' => 'rev_sha1',
                'text_id' => 'rev_text_id',
                'content_model' => 'rev_content_model',
                'namespace' => 'page_namespace',
                'title' => 'page_title',
            ];
            $joins = [
                'slots' => [ 'LEFT JOIN', 'rev_id=slot_revision_id' ],
                'page' => [ 'LEFT JOIN', 'rev_page=page_id' ],
            ];
            $startOption = 'start-revision';
        } else {
            $idField = 'ar_rev_id';
            $tables = [ 'archive', 'slots' ];
            $fields = [
                'rev_id' => 'ar_rev_id',
                'len' => 'ar_len',
                'sha1' => 'ar_sha1',
                'text_id' => 'ar_text_id',
                'content_model' => 'ar_content_model',
                'namespace' => 'ar_namespace',
                'title' => 'ar_title',
            ];
            $joins = [
                'slots' => [ 'LEFT JOIN', 'ar_rev_id=slot_revision_id' ],
            ];
            $startOption = 'start-archive';
        }
 
        if ( !$this->dbw->fieldExists( $table, $fields['text_id'], __METHOD__ ) ) {
            $this->writeln( "No need to populate, $table.{$fields['text_id']} field does not exist" );
            return;
        }
 
        $minmax = $this->dbw->selectRow(
            $table,
            [ 'min' => "MIN( $idField )", 'max' => "MAX( $idField )" ],
            '',
            __METHOD__
        );
        if ( $this->hasOption( $startOption ) ) {
            $minmax->min = (int)$this->getOption( $startOption );
        }
        if ( !$minmax || !is_numeric( $minmax->min ) || !is_numeric( $minmax->max ) ) {
            // No rows?
            $minmax = (object)[ 'min' => 1, 'max' => 0 ];
        }
 
        $batchSize = $this->getBatchSize();
 
        for ( $startId = $minmax->min; $startId <= $minmax->max; $startId += $batchSize ) {
            $endId = min( $startId + $batchSize - 1, $minmax->max );
            $rows = $this->dbw->select(
                $tables,
                $fields,
                [
                    "$idField >= $startId",
                    "$idField <= $endId",
                    'slot_revision_id IS NULL',
                ],
                __METHOD__,
                [ 'ORDER BY' => 'rev_id' ],
                $joins
            );
            if ( $rows->numRows() !== 0 ) {
                $this->populateContentTablesForRowBatch( $rows, $startId, $table );
            }
 
            $elapsed = microtime( true ) - $t0;
            $this->writeln(
                "... $table processed up to revision id $endId of {$minmax->max}"
                . " ($this->count rows in $elapsed seconds)"
            );
        }
 
        $elapsed = microtime( true ) - $t0;
        $this->writeln( "Done populating $table table. Processed $this->count rows in $elapsed seconds" );
    }
 
    private function populateContentTablesForRowBatch( IResultWrapper $rows, $startId, $table ) {
        $this->beginTransaction( $this->dbw, __METHOD__ );
 
        if ( $this->contentRowMap === null ) {
            $map = [];
        } else {
            $map = &$this->contentRowMap;
        }
        $contentKeys = [];
 
        try {
            // Step 1: Figure out content rows needing insertion.
            $contentRows = [];
            foreach ( $rows as $row ) {
                $revisionId = $row->rev_id;
 
                Assert::invariant( $revisionId !== null, 'rev_id must not be null' );
 
                $model = $this->getContentModel( $row );
                $modelId = $this->contentModelStore->acquireId( $model );
                $address = SqlBlobStore::makeAddressFromTextId( $row->text_id );
 
                $key = "{$modelId}:{$address}";
                $contentKeys[$revisionId] = $key;
 
                if ( !isset( $map[$key] ) ) {
                    $this->fillMissingFields( $row, $model, $address );
 
                    $map[$key] = false;
                    $contentRows[] = [
                        'content_size' => (int)$row->len,
                        'content_sha1' => $row->sha1,
                        'content_model' => $modelId,
                        'content_address' => $address,
                    ];
                }
            }
 
            // Step 2: Insert them, then read them back in for use in the next step.
            if ( $contentRows ) {
                $id = $this->dbw->selectField( 'content', 'MAX(content_id)', '', __METHOD__ );
                $this->dbw->insert( 'content', $contentRows, __METHOD__ );
                $res = $this->dbw->select(
                    'content',
                    [ 'content_id', 'content_model', 'content_address' ],
                    'content_id > ' . (int)$id,
                    __METHOD__
                );
                foreach ( $res as $row ) {
                    $key = $row->content_model . ':' . $row->content_address;
                    $map[$key] = $row->content_id;
                }
            }
 
            // Step 3: Insert the slot rows.
            $slotRows = [];
            foreach ( $rows as $row ) {
                $revisionId = $row->rev_id;
                $contentId = $map[$contentKeys[$revisionId]] ?? false;
                if ( $contentId === false ) {
                    throw new \RuntimeException( "Content row for $revisionId not found after content insert" );
                }
                $slotRows[] = [
                    'slot_revision_id' => $revisionId,
                    'slot_role_id' => $this->mainRoleId,
                    'slot_content_id' => $contentId,
                    // There's no way to really know the previous revision, so assume no inheriting.
                    // rev_parent_id can get changed on undeletions, and deletions can screw up
                    // rev_timestamp ordering.
                    'slot_origin' => $revisionId,
                ];
            }
            $this->dbw->insert( 'slots', $slotRows, __METHOD__ );
            $this->count += count( $slotRows );
            $this->totalCount += count( $slotRows );
        } catch ( \Exception $e ) {
            $this->rollbackTransaction( $this->dbw, __METHOD__ );
            $this->fatalError( "Failed to populate content table $table row batch starting at $startId "
                . "due to exception: " . $e->__toString() );
        }
 
        $this->commitTransaction( $this->dbw, __METHOD__ );
    }
 
    private function getContentModel( $row ) {
        if ( isset( $row->content_model ) ) {
            return $row->content_model;
        }
 
        $title = Title::makeTitle( $row->namespace, $row->title );
 
        return ContentHandler::getDefaultModelFor( $title );
    }
 
    private function writeln( $msg ) {
        $this->output( "$msg\n" );
    }
 
    private function fillMissingFields( $row, $model, $address ) {
        if ( !isset( $row->content_model ) ) {
            // just for completeness
            $row->content_model = $model;
        }
 
        if ( isset( $row->len ) && isset( $row->sha1 ) && $row->sha1 !== '' ) {
            // No need to load the content, quite now.
            return;
        }
 
        $blob = $this->blobStore->getBlob( $address );
 
        if ( !isset( $row->len ) ) {
            // NOTE: The nominal size of the content may not be the length of the raw blob.
            $handler = ContentHandler::getForModelID( $model );
            $content = $handler->unserializeContent( $blob );
 
            $row->len = $content->getSize();
        }
 
        if ( !isset( $row->sha1 ) || $row->sha1 === '' ) {
            $row->sha1 = SlotRecord::base36Sha1( $blob );
        }
    }
}
 
$maintClass = 'PopulateContentTables';
require_once RUN_MAINTENANCE_IF_MAIN;