Advanced Ad Hoc Star Query Processing
Nikos Karayannidis (National Technical University of Athens, Greece), Aris Tsois (National Technical University of Athens, Greece) and Timos Sellis (National Technical University of Athens, Greece)
Copyright: © 2007
Star queries are the most prevalent kind of queries in data warehousing, OLAP and business intelligence applications. Thus, there is an imperative need for efficiently processing star queries. To this end, a new class of fact table organizations has emerged that exploits path-based surrogate keys in order to hierarchically cluster the fact table data of a star schema. In the context of these new organizations, star query processing changes radically. In this chapter, we present a complete abstract processing plan that captures all the necessary steps in evaluating such queries over hierarchically clustered fact tables. Furthermore, we realize the abstract operations in terms of physical operations over the CUBE File data structure. Finally we discuss star query optimization issues over the presented abstract plan.