/**
  * Initialises the database connection for the 'otherdb' cache type.
  * @return moodle_database the DB connection to use.
  */
 protected static function get_other_db()
 {
     if (!is_null(self::$otherdb)) {
         return self::$otherdb;
     }
     $dboptions = array();
     if (!empty(self::$config->cascachedbsocket)) {
         $dboptions['dbsocket'] = true;
     }
     self::$otherdb = moodle_database::get_driver_instance(self::$config->cascachedbtype, self::$config->cascachedblibrary);
     self::$otherdb->connect(self::$config->cascachedbhost, self::$config->cascachedbuser, self::$config->cascachedbpass, self::$config->cascachedbname, self::$config->cascachedbprefix, $dboptions);
     return self::$otherdb;
 }