Ускорение минимального/максимального значения свойства

public function addMinMaxProperty()
   {
      $iCurrentShopGroup = intval($this->group);
   
      $linkedObject = Core_Entity::factory('Shop_Item_Property_List', 3);
      $aProperties = $linkedObject->getPropertiesForGroup($iCurrentShopGroup);

      $oShop = $this->getEntity();
  
      foreach($aProperties as $current_property)
      {
      $aPropertyValues = '';
      $oProperty = Core_Entity::factory('Property', $current_property->id);

      $oShop_Items = $oShop->Shop_Items;
      $this->_applyItemConditionsQueryBuilder($oShop_Items->queryBuilder());

      $aShop_Items = $oShop_Items->getAllByShop_Group_Id($iCurrentShopGroup);            

      foreach($aShop_Items as $oShop_Item)
      {
         $oPropertyValue = $oProperty->getValues($oShop_Item->id, FALSE);

         if(isset($oPropertyValue[0]) and isset($oPropertyValue[0]->value))
         {
               $aPropertyValues[] = $oPropertyValue[0]->value;
         }
      }

      if(is_array($aPropertyValues))
      {
         $minPropertyValue = min($aPropertyValues);
         $maxPropertyValue = max($aPropertyValues);

         $this->addEntity(
               Core::factory('Core_Xml_Entity')
                        ->name('minPropertyValue')
                        ->value($minPropertyValue)
                        ->addAttribute('id', $current_property->id)
                  )
               ->addEntity(
                  Core::factory('Core_Xml_Entity')
                        ->name('maxPropertyValue')
                        ->value($maxPropertyValue)
                        ->addAttribute('id', $current_property->id)
               );
      }
               
      }

      return $this;
   }