When streams have high arrival rates, we propose an approach incorporating front-shedding and rear-shedding, and find an optimal trade-off between them . as for the scenarios of variable speed ratio, we develop a plan reallocating cpu resources and dynamically resizing the windows 例如在数据流上作连接操作时,因为流数据的在线无界速度可变等特性,通常采用的做法是改变连接的语义,将参与连接的元组集合限制在滑动窗口上进行。