分布式数据库系统中基于半连接的查询处理

QUERY PROCESSING BASED ON THE SEMI-JOIN IN THE DISTRIBUTED DB SYSTEM

本文较全面地总结了分布式数据库系统的查询处理,并提出用HASHING 方法减少半连接通讯的开销是有利的。本文引进了带序号的半连接关系操作,用它总可以求得有回路查询的全缩减S。

The query processing in the distributed database systems is compre-hensively summarized.This paper shows that using HASHING method for thereduction of semi-join communication cost is beneficial.It also introduces arelational operator semi-join with ordinal numbers.By means of it,the fullreduction S~* of cyclic queries can be always obtained.