moveToExternal.php

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<?php
define( 'REPORTING_INTERVAL', 1 );

if ( !defined( 'MEDIAWIKI' ) ) {
    $optionsWithArgs = [ 'e', 's' ];
    require_once __DIR__ . '/../commandLine.inc';
    require_once 'resolveStubs.php';

    $fname = 'moveToExternal';

    if ( !isset( $args[0] ) ) {
        print "Usage: php moveToExternal.php [-s <startid>] [-e <endid>] <cluster>\n";
        exit;
    }

    $cluster = $args[0];
    $dbw = wfGetDB( DB_MASTER );

    if ( isset( $options['e'] ) ) {
        $maxID = $options['e'];
    } else {
        $maxID = $dbw->selectField( 'text', 'MAX(old_id)', false, $fname );
    }
    $minID = isset( $options['s'] ) ? $options['s'] : 1;

    moveToExternal( $cluster, $maxID, $minID );
}

function moveToExternal( $cluster, $maxID, $minID = 1 ) {
    $fname = 'moveToExternal';
    $dbw = wfGetDB( DB_MASTER );
    $dbr = wfGetDB( DB_REPLICA );

    $count = $maxID - $minID + 1;
    $blockSize = 1000;
    $numBlocks = ceil( $count / $blockSize );
    print "Moving text rows from $minID to $maxID to external storage\n";
    $ext = new ExternalStoreDB;
    $numMoved = 0;

    for ( $block = 0; $block < $numBlocks; $block++ ) {
        $blockStart = $block * $blockSize + $minID;
        $blockEnd = $blockStart + $blockSize - 1;

        if ( !( $block % REPORTING_INTERVAL ) ) {
            print "oldid=$blockStart, moved=$numMoved\n";
            wfWaitForSlaves();
        }

        $res = $dbr->select( 'text', [ 'old_id', 'old_flags', 'old_text' ],
            [
                "old_id BETWEEN $blockStart AND $blockEnd",
                'old_flags NOT ' . $dbr->buildLike( $dbr->anyString(), 'external', $dbr->anyString() ),
            ], $fname );
        foreach ( $res as $row ) {
            # Resolve stubs
            $text = $row->old_text;
            $id = $row->old_id;
            if ( $row->old_flags === '' ) {
                $flags = 'external';
            } else {
                $flags = "{$row->old_flags},external";
            }

            if ( strpos( $flags, 'object' ) !== false ) {
                $obj = unserialize( $text );
                $className = strtolower( get_class( $obj ) );
                if ( $className == 'historyblobstub' ) {
                    # resolveStub( $id, $row->old_text, $row->old_flags );
                    # $numStubs++;
                    continue;
                } elseif ( $className == 'historyblobcurstub' ) {
                    $text = gzdeflate( $obj->getText() );
                    $flags = 'utf-8,gzip,external';
                } elseif ( $className == 'concatenatedgziphistoryblob' ) {
                    // Do nothing
                } else {
                    print "Warning: unrecognised object class \"$className\"\n";
                    continue;
                }
            } else {
                $className = false;
            }

            if ( strlen( $text ) < 100 && $className === false ) {
                // Don't move tiny revisions
                continue;
            }

            # print "Storing "  . strlen( $text ) . " bytes to $url\n";
            # print "old_id=$id\n";

            $url = $ext->store( $cluster, $text );
            if ( !$url ) {
                print "Error writing to external storage\n";
                exit;
            }
            $dbw->update( 'text',
                [ 'old_flags' => $flags, 'old_text' => $url ],
                [ 'old_id' => $id ], $fname );
            $numMoved++;
        }
    }
}