一种改进的半连接查询优化算法

An Improved Semi-join Query Optimization Algorithm

查询优化是分布式数据库研究和关注的核心问题之一,为提高分布式数据库的查询效率,通过分析分布式数据库管理系统的特点,找出了影响分布式数据库管理系统查询效率的关键因素,并讨论了直接连接查询的常见策略和半连接查询的原理、实现方法以及所花费的传输代价,同时针对分布式数据库应用中存在大量重复查询操作的特点,提出了一种改进的半连接查询策略。最后结合应用实例对比传统半连接算法与改进后的算法,表明改进后的算法降低了数据传输量,缩短了查询处理时间,提高了查询效率。

Query optimization is one of the core issues of the distributed database. In order to improve the query efficiency of the distribu- ted database, the characteristics of the distributed data management system are analyzed and the key factors which influence the query efficiency of the distributed data management are found out, then the strategies of direct connection query and the principle and realization of semi-join query and the transmission costs are discussed. For the amount of repeat queries existing in the distributed database applica- tions, an improved strategy for the semi-join queries was put forward. With an application example in contrast to traditional semi-join al- gorithm and the improved algorithm,the improved algorithm reduces the amount of data transmission,shortens the query processing time and improves the efficiency of the query.