pfSense

		if($rowcountdiff < 0){

			/* remove excess rows */

			$r = - $rowcountdiff;

			$rrdoldxml['rra'][$i]['database']['row'] = array_slice($rrdoldxml['rra'][$i]['database']['row'],$r);

			$rowcountold = count($rrdoldxml['rra'][$i]['database']['row']);

			if($rowcountold == $rowcountnew){

				log_error(sprintf("Row count successfully reduced by $r to $rowcountold\n"));

			}

		}

		elseif($rowcountdiff > 0) {

			/* save old rows for a bit before we put the required empty rows before it */

			$rowsdata = $rows;

			$rowsempty = array();

			$r = 0;

			while($r < $rowcountdiff) {

				$rowsempty[] = $rrdnewxml['rra'][$i]['database']['row'][$r];

				$r++;

			}

			$rows = $rowsempty + $rowsdata;