More efficient way to sort \Phalcon\Mvc\Model\Resultset

Hi, since subqueries hasn't been supported in phql, I need to sort my pagination items in PHP. I've done like this code below. It worked, but it uses iteratortoarray which dumps the Resultset to array. Is there more efficient, less memory usage other than this approach?

namespace BI;

class PradSorter {
    public static function cmp($a, $b){
        if($a->row_count == $b->row_count)
            return 0;
        return $a->row_count > $b->row_count ? +1 : -1;

    public static function sort(\Phalcon\Mvc\Model\Resultset $x){
        $x = iterator_to_array($x);
        usort($x, ['\BI\PradSorter', 'cmp']);
        return $x;


You can order the resultset in the database rather than doing it in PHP:

$robots = Robots::find(['order' => 'row_count']);
$robots = Robots::find(['order' => 'row_count DESC']);

@Phalcon, of course I know the 'order' option, I've been using it since ver 0.7.0 :) What I'm trying to achieve is this:

SELECT `prad`.* 
FROM `prad` AS `prad`
ORDER BY `prad`.`publish_dt` DESC LIMIT 25
) as x
ORDER BY x.row_count

Since, PHQL not support subquery I fetch prad sorted by publishdt using query builder pagination, And then I have to sort the Resultset by rowcount in PHP