do {
$res = $dbw->select( 'text', array( 'old_id','old_flags','old_text' ),
"old_id>=$start", __METHOD__, array( 'ORDER BY' => 'old_id', 'LIMIT' => $chunksize, 'FOR UPDATE' ) );
do {
$res = $dbw->select( 'text', array( 'old_id','old_flags','old_text' ),
"old_id>=$start", __METHOD__, array( 'ORDER BY' => 'old_id', 'LIMIT' => $chunksize, 'FOR UPDATE' ) );