期刊名称：International Journal of Computer Applications and Information Technology
印刷版ISSN：2278-7720
出版年度：2014
卷号：5
期号：2
页码：70-76
出版社：Mahadev Educational Society
摘要：In distributed database query optimization, one of the main factors affecting the performance of an execution strategy is the intermediate fragment sizes produced during the execution of the sub query operations. This paper analyses static vs. dynamic calculation for selectivity of intermediate relations generated in query processing. A Dynamic model for selectivity evaluation (DSET) has been proposed to simulate sub-query allocation and cost optimization for a distributed database query processing environment. Experiments have shown that dynamic evaluation of selectivity factor of sub query operation has significantly reduced the total query cost than its static estimation.
