PHP独立Session数据库存储操作类分享(7)

$result = $this->_mysqli->query($sql);
            $row = $result->fetch_array(MYSQLI_ASSOC);
                return $row[‘cnt'];
        }

private function _gc()
        {
                $rand_num = rand(); # randow integer between 0 and getrandmax()
                if ($rand_num < 100)
                {
                        $sql = ‘DELETE FROM ‘ . $this->_config[‘tablename'] . ‘
                                WHERE heartbeat < '‘ . date(‘Y-m-d H:i:s' ,TIMENOW – $this->_config[‘cookie_timeout']) . ‘'‘;

$this->_mysqli->query($sql);
                }
        }

public function __destruct()
        {
            $this->_save();
            $this->_gc();
            $this->_mysqli->close();
        }

}