static function isCacheUpToDate($class, $name)
 {
     /** @var self $instance */
     $instance = new $class();
     $spec = $instance->_spec;
     $status_result = $instance->getDS()->loadHash("SHOW TABLE STATUS LIKE '{$spec->table}'");
     $data_date = $status_result["Update_time"];
     $cache_date = SHM::modDate($name);
     return $cache_date > $data_date;
 }