一种改进的多关系半连接数据库查询算法研究

Research on Query Optimization Algorithm of Distributed Data Base Based on Relation Semi Join

由于普通多关系半连接优化算法，分布式数据库系统的缓冲区不能作为查询的中间结果的最后装配站点，文章提出了改进普通多关系半连接的数据库查询优化算法，实验结果表明改进的多关系半连接的查询优化算法明显地减少了中间结果数据量，有效地降低了网络通信总代价。

This paper design a new algorithm named the query optimization algorithm based on multiple relations semi join, this new algorithm can be applied to the circumstance in which the cache of DDBS is the final assembly site of temporary query result. The algorithm reduces the temporary result data number distinctly and reduce the network communication total cost efficiently through experiment