The document discusses data warehouse architecture and decision support systems. It explains that data warehouses typically use a relational database as the warehouse database server, while OLAP servers can be either relational OLAP or multidimensional OLAP. It also outlines the three tiers of a complete decision support system including the data warehouse server, OLAP servers, and clients. Finally, it provides information on why Hyperion Essbase is a leader in business intelligence software.