sel ect * fr om b_xml_tree wh ere id=(select max(id) fr om b_xml_tree);

         if(file_exists($ABS_FILE_NAME) && is_file($ABS_FILE_NAME) && ($fp = fopen($ABS_FILE_NAME, "rb"))
         {
            if($obXMLFile->ReadXMLToDat abase($fp, $NS, $INTERVAL))
               $NS["STEP"]++;
            fclose($fp);
         }

CIBlockXMLFile::ReadXMLToDat abase( resource fp, array &NS,
 int time_limit = 0,
 int read_size = 1024,
);

TRUNCATE TABLE `b_xml_tree`;