In this paper, we discuss common optimization method of join queries within DDB system, and then give an intensive description of join optimization based on pre-test technology we applied, we make final analyses and conclusions of this paper at last.

• 本文介绍了在分布式数据库系统中对联接查询的一般处理方法；详细论述了笔者提出的一种在分布式数据库中基于事先测试的优化联接查询技术；并进行了分析与总结.