/**
  * Class constructor
  *
  * @param MySqlDatabase db
  * @param Logger $logger
  * @param bool $memcahe_on
  *
  */
 public function __construct(MySqlDatabase $db, Logger $logger = null)
 {
     parent::__construct($db, $logger);
     $this->memcacheConfig = ConfigManager::getConfig("Db", "Memcache")->AuxConfig;
     if (strpos($this->memcacheConfig->keyPrefix, ":")) {
         throw new RuntimeException("Memcache key prefix can't contain colon \":\"!");
     }
     if ($this->memcacheConfig->enabled) {
         $this->memcache = new MemcacheWrapper($this->memcacheConfig->host, $this->memcacheConfig->port);
     }
 }