%0 Journal Article
%T An Aggregation Algorithm Based on Group Numbers<br>基于分组序号的聚集算法
%A FENG Jian-Hu
%A JIANG Xu-Dong
%A MENG Xian-Hu
%A <br>冯建华
%A 蒋旭东
%A 孟宪虎
%J 软件学报
%D 2003
%I 
%X OLAP (online analytical processing) queries are complex. When implemented in SQL (structured query language), they usually involve multi-table join and aggregate operations. As a result, how to improve the performance of the multi-table join and aggregate operations becomes a key issue for ROLAP (relational OLAP) query evaluation. To solve this problem, an aggregation algorithm based on group numbers named MuGA (group number based aggregation with multi-table join) is proposed in this paper. By taking the characteristics of star schema into consideration, the algorithm combines the aggregation operation with the novel multi-table join algorithm, Mjoin (multi-table join), and replaces the sorting and hashing method by computed group numbers in aggregation computing. As a result, the algorithm can not only reduce the CPU time, but also reduce the disk I/Os for OLAP queries. As illustrated by the experiments, the performance of the algorithm MuGA is superior to original aggregation methods and the new sorting based method for aggregation.
%K data warehouse
%K OLAP(online analytical processing)
%K multi-table join
%K aggregation query<br>数据仓库
%K 联机分析处理
%K 多表连接
%K 聚集查询
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=5B3AB970F71A803DEACDC0559115BFCF0A068CD97DD29835&cid=8240383F08CE46C8B05036380D75B607&jid=7735F413D429542E610B3D6AC0D5EC59&aid=5B2B6EC69EFBE336&yid=D43C4A19B2EE3C0A&vid=F3583C8E78166B9E&iid=0B39A22176CE99FB&sid=8B59EA573021D671&eid=F8035C8B7D8A4264&journal_id=1000-9825&journal_name=软件学报&referenced_num=3&reference_num=17