/**
  * 判断是否向db读取数据
  * 返回值为true表示从db中获得,否则从cache中获得
  * @param int $deviceId
  * @return boolean 
  */
 public function check2Db($userId, $deviceId, $eventId)
 {
     $cacheUserId = $this->get($this->getUserKey($userId));
     $cacheEventId = $this->get($this->getDeviceEventKey($deviceId));
     if ($cacheUserId == false || $cacheEventId == false) {
         //当3者之一都不存在记录,
         return true;
     }
     $userMaxId = MiniEvent2::getInstance()->getMaxIdByUser2($userId);
     if ($cacheUserId != $userMaxId || $cacheEventId != $eventId) {
         return true;
     }
     return false;
 }