Mastering Data Warehouse Aggregates: Solutions for Star Schema Performance

Chapter 1. Fundamentals of Aggregates

A decade ago, Ralph Kimball described aggregate tables as "the single most dramatic way to improve performance in a large data warehouse." Writing in DBMS Magazine ("Aggregate Navigation with (Almost) No Metadata," August 1996), Kimball continued:

Aggregates can have a very significant effect on performance, in some cases speeding queries by a factor of one hundred or even one thousand. No other means exist to harvest such spectacular gains.

This statement rings as true today as it did ten years ago. Since then, advances in hardware and software have dramatically improved the capacity and performance of the data warehouse. Aggregates compound the effect of these improvements, providing performance gains that fully harness capabilities of the underlying technologies.

And the pressure to improve data warehouse performance is as strong as ever. As the baseline performance of underlying technologies has improved, warehouse developers have responded by storing and analyzing larger and more granular volumes of data. At the same time, warehouse systems have been opened to larger numbers of users, internal and external, who have come to expect instantaneous access to information.

This book empowers you to address these pressures. Using aggregate tables, you can achieve an extraordinary improvement in the speed of your data warehouse. And you can do it today, without making expensive upgrades to hardware, converting to a new database platform, or ...