Doctrine_Pager bug with Oracle. getNumResults doesn't return the correct number of records

class ReviewListTable extends Doctrine_Table
{
 public function getAvailable()
 {
   return $this->createQuery()
   ->select('DISTINCT(to_char(file_date, \'YYYY-MM-DD\')) fdate')
   ->orderBy('fdate DESC');
 }
}

$this->pager = new Doctrine_Pager(
                           Doctrine_Core::getTable('ReviewList')->getAvailable(),
                           $request->getParameter('page', 1),
                           20);

$rs = $this->pager->execute();
echo $pager->getNumResults();