Query Optimization Techniques for OLAP Applications: An ORACLE versus MS-SQL Server Comparative Study

Abstract

Query optimization in OLAP applications is a novel problem. A lot of research was introduced in the area of optimizing query performance, however great deal of research focused on OLTP applications rather than OLAP. In order to reach the output results OLAP queries extensively asks the database, inefficient processing of those queries will have its negative impact on the performance and may make the results useless. Techniques for optimizing queries include memory caching, indexing, hardware solutions, and physical database storage. Oracle and MS SQL Server both offer OLAP optimization techniques, the paper will review both packages’ approaches and then proposes a query optimization strategy for OLAP applications. The proposed strategy is based on use of the following four ingredients: 1- intermediate queries; 2- indexes both BTrees and Bitmaps; 3- memory cache (for the syntax of the query) and secondary storage cache (for the result data set); and 4- the physical database storage (i.e. binary storage model) accompanied by its hardware solution