摘要： 数据流中的查询计划需要不断进行适应性优化，针对该特征提出一种查询计划的并行迁移策略。该策略能确保在输出过程中不丢失元组或产生冗余元组，维持正确的元组输出时序。实验结果证明，该策略可以使查询计划平滑过渡，避免迁移过程出现无元组输出的空白期，在系统资源紧张和数据流流速过大时，维持较少的中间元组数和较大输出速率。

关键词: 数据流, 查询计划, 并行迁移策略

Abstract: This paper presents a new parallel migration strategy for a query plan in order to adapt the continuity of queries and variability of system environment and date itself. This strategy can ensure output results correctness and time sequence. Experimental results show that this strategy can insure smooth migration between query plans, avoid the silence that without output tuple of migration process, maintain a low intermediate tuple count and high output rate when the system resource is lacking and the speed of data stream is too fast.

Key words: data stream, query plan, parallel migration strategy

中图分类号: 

• TP391