HoliAdapt—数据流中一种适应性查询处理策略

针对数据流上连续查询处理的特征，我们从选择率和执行时间的角度出发,考虑内存使用量和输出延迟适应性因素，提出一种适应性的查询处理策略—HoliAdapt。该策略基于查询窗口动态地收集统计信息，利用数学方法不断地优化查询计划，通过核心调度方法，对操作符进行适应性的调度,有效地减少时间延迟和内存使用量，提高系统查询的效率。

HoliAdapt - An adaptive query processing strategy over data stream

Continuous query has some special properties. With this motivation in mind, we think carefully about adaptive factors: run-time memory usage and time latency based on selectivity and processing time. Then we present an adaptive query processing strategy —HoliAdapt. First, we collect continuously statistical information over query windows, then we optimize dynamically query planning according to computing about statistical information. Thereafter, we adopt a scheduling strategy to schedule adaptively operators. Experiments have proved that this query processing strategy can availably minimize run-time memory usage and time latency, and ultimately improve performance of query.