Cost-Based Oracle Fundamentals

by Jonathan Lewis, Thomas Kyte

The insights that Jonathan provides into the workings of the cost-based optimizer will make a DBA a better designer, and a Developer a better SQL coder. Both groups will become better troubleshooters.

— Thomas Kyte, VP (Public Sector), Oracle Corporation

The question, "Why isn't Oracle using my index?" must be one of the most popular (or perhaps unpopular) questions ever asked on the Oracle help forums. You've picked exactly the right columns, you've got them in the ideal order, you've computed statistics, you've checked for null columns--and the optimizer flatly refuses to use your index unless you hint it. What could possibly be going wrong?

If you've suffered the frustration of watching the optimizer do something completely bizarre when the best execution plan is totally obvious, or spent hours or days trying to make the optimizer do what you want it to do, then this is the book you need. You'll come to know how the optimizer "thinks," understand why it makes mistakes, and recognize the data patterns that make it go awry. With this information at your fingertips, you will save an enormous amount of time on designing and trouble-shooting your SQL.

The cost-based optimizer is simply a piece of code that contains a model of how Oracle databases work. By applying this model to the statistics about your data, the optimizer tries to efficiently convert your query into an executable plan. Unfortunately, the model can't be perfect, your statistics can't be perfect, and the resulting execution plan may be far from perfect.

In Cost-Based Oracle Fundamentals, the first book in a series of three, Jonathan Lewis--one of the foremost authorities in this field--describes the most commonly used parts of the model, what the optimizer does with your statistics, and why things go wrong. With this information, you'll be in a position to fix entire problem areas, not just single SQL statements, by adjusting the model or creating more truthful statistics.

560 pages, Paperback

First published November 1, 2005

Reviews

[Michael Finocchiaro · Rating 5 out of 5]

Hands-down, the BEST book about how Oracle's complex optimiser works. The title says "volume 1" and I met Lewis at Oracle OpenWorld a few years back and he confirmed my suspicions that writing this book was so hard, he was too exhausted to write a sequel. It is difficult but an excellent source of information. When you realize that Oracle has as many patents and programmers for their optimiser as Microsoft has for their Windows operating system, you get an idea of the titanic work it required to write this extraordinary book!

[Colin Hoad · Rating 5 out of 5]

Nobody (including those who programmed it themselves) understands the Oracle CBO better than Jonathan Lewis. If you want to make sense out of how and why Oracle chooses to execute queries in the way that it does, read this book. It is dense, complicated material but Lewis nevertheless does his utmost to make it both clear and comprehensive.

[Daniel Galassi · Rating 4 out of 5]

After asking myself why some of the data models were performing so badly I realised I had to read this book (sure, among others). But this was the first book about cost-based optimisation I was able to read from cover to cover... and understand how to use the myriad of features Oracle databases have to offer.
The authors know CBO extremely well and the book is written in a way that a good developer (doesn't need to be a seasoned or expert) will take huge advantage of.

[Neil · Rating 4 out of 5]

Currently reading for work. I wish there was a good place to get reviews of technical manuals hopefully my review will help.

[Corrado Piola · Rating 5 out of 5]

I read it a lot of time ago. Really a must! Optimizer internals in great detail.