do {
$res = $dbr->select( 'image', '*', array( 'img_name > ' . $dbr->addQuotes( $start ) ),
__METHOD__, array( 'LIMIT' => $this->mBatchSize ) );
do {
$res = $dbr->select( 'image', '*', array( 'img_name > ' . $dbr->addQuotes( $start ) ),
__METHOD__, array( 'LIMIT' => $this->mBatchSize ) );