When Stars Implode

I've learned one important and somewhat humbling lesson during my four years of presenting my data warehousing papers at shows and conferences: Even DBAs are not infallible! I've always assumed that if a feature existed in Oracle, the typical DBA would use it correctly. But, I've run into hundreds of people who claim that their data warehouse must be special because they cannot get star schema techniques to work for them. Even more disturbing , they just assume they've hit the "brick wall" since their data warehouses are so big. The problem is that 99% of the time, they're not yet even a terabyte in size when they throw in the towel. So how and why does this happen?

The only explanation I can find is that most of these DBAs often take issue with one or two concepts presented in this book and choose not to implement them. They wrongly assume that doing 95% of these techniques will yield almost the same great results. It definitely will not. If you skip even what you consider to be the most trivial step, you will never reap the big rewards. I've seen and heard of these same techniques working on star schema data warehouses approaching 100 terabytes in size. So they can and do work. But you must have faith and implement the whole package.

I've found that it helps on those occasions when a DBA has issues with some of my advice to show him or her other references offering similar or the same advice. So here are a few Oracle white papers I strongly recommend (with the most important ones in bold):

• " Star Queries in Oracle 8 ", June 1997

• "Data Warehouse Performance Enhancements with Oracle 9i", April 2001

• "Oracle 9i Performance and Scalability in DSS Environments", April 2001

• " Key Data Warehousing Features in Oracle 9i: A comparative Performance Analysis ", September 2001

• " Query Optimization in Oracle 9i ", February 2002

You can download all these papers from either Oracle's Metalink Support (www.oracle.com/support/ metalink ) or Oracle's Technology Network (technet.oracle.com).