数据集成系统中多查询优化的研究

Multiple-query Optimizations in Data Integration

多查询优化的主要目的就是为了消除多个查询间存在的冗余。基于扩展查询头部变量算法,提出一种多查询优化算法。其主要思想是:通过构造一棵查询集合的伪包含树,建立查询间的联系。然后通过解析这棵树,来构造全局优化的查询计划。

The main target of multiple-query optimization is to eliminate the redundancies in multiple queries. Based on the extended query of head variable algorithm, a multiple query optimization algorithm is presented. The main idea is to build the relation among queries with constructing a pseudo containment tree of the query set. Then by resolving this tree, the query plan of global optimization is construct.