Algorithms for data warehouse design to enhance decision-making

On-line analytical processing (OLAP) queries are strongly affected by the amount data needed to be accessed from the disk. Therefore, there is a need to employ techniques that can facilitate efficient execution of these queries. There has been a lot of work to optimize the performance of relational data warehouses. Among the two fragmentation techniques, vertical fragmentation is often considered more complicated than horizontal, it nearly impossible to obtain an optimal solution. Data partitioning concept that has been studied in the context of relational databases aims to reduce query execution time and facilitate the parallel execution of queries. In this paper, we develop a new framework based on genetic algorithm for applying the partitioning technique on relational DW schema (star schema) to minimize the total query execution cost. We develop an analytical cost model for executing a set of OLAP queries on a partitioned star schema. We conduct experiments to evaluate the utility of partitioning in efficiently executing OLAP queries. Finally, we show how partitioning can be used to facilitate parallel execution of OLAP queries. Key-Words: Partitioning, warehouse, OLAP queries, Genetic algorithm, penalty function, query optimization.