Physical Data Warehouse Design

Abstract

The physical design of data warehouses is crucial to ensure adequate query response time. There are typically three common techniques for improving performance in data warehouse systems: materialized views, indexing, and partitioning. A materialized view is a view that is physically stored in a database, which enhances query performance by precalculating costly operations such as joins and aggregations. With respect to indexing, traditional techniques used in OLTP systems are not appropriate for multidimensional data. Thus, alternative indexing mechanisms are used in data warehouses, typically bitmap and join indexes. Finally, partitioning or fragmentation divides the contents of a relation into several files, typically based on a range of values of an attribute.