期刊名称：International Journal of Computer Science & Information Technology (IJCSIT)
印刷版ISSN：0975-4660
电子版ISSN：0975-3826
出版年度：2012
卷号：4
期号：1
页码：259
出版社：Academy & Industry Research Collaboration Center (AIRCC)
摘要：Cost based query optimizers have seen numerous changes and up gradations since their birth in the formof System R query optimizer. Query Optimization is a process of selecting an optimal Query ExecutionPlan from a number of plans available for execution of query and this selection of best plan is verycritical to the performance of a relational database. Picasso is a Query Optimizer analysis tooldeveloped by the Database lab of Indian Institute of Science, Bangalore [24]. It provides graphicalinsights into the Query Optimization Process. With so many Database systems available in the marketand each one having its own secret recipe of Query Optimization it becomes difficult to know whatactually happens during query optimization. Picasso enables users to explore the world of queryoptimization. In this paper we briefly introduce the query optimization concept and then describe aspecial technique known as Plan Diagram Reduction which improves the efficiency of QueryOptimization Process and makes it more Robust.
关键词：Query Optimization; Selectivity; Plan Cardinality; Plan Diagrams; Checkpoints; TPCH
