Cost-Based Oracle Fundamentals (Expert's Voice in Oracle) at Dominant Systems Book Store

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</a> </blockquote> — Thomas Kyte, VP (Public Sector), Oracle Corporation</div>

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&emdash;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&emdash;one of the foremost authorities in this field&emdash;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.

Customer Reviews & Comments
This is the book for you. This book is, well, in a word amazing. If you have ever been baffled or bemused by why the heck did the optimizer do that, or as Jonathan wrote on page 299: "I am reluctant to call something a bug unless I can work out what Oracle is doing and can prove that its doing something irrational. Too many people say, Its a bug when they really mean I dont know why this happened." You will absolutely love this book. In it you will discover the hows and whys of the optimizer. Why statistics matter, how they matter. Whats up with histograms when and where do we need them, what affect do they have. Sprinkled throughout the book are random insights like this one: "There are many ways to implement Oracle systems badly, and as a general rule, anything that hides useful information from the optimizer is a bad idea. One of the simple, and highly popular, strategies for doing this is to stick all of your reference data into a single table with a type column. The results can be catastrophic as far as the optimizer is concerned." And then is goes on to say why. That is what I really really like it goes on to say why. I hate it when statements are made and no reasoning is made why. You will find none of that in this book. Jonathan did one thing in this book that Ill definitely be stealing myself. One neat thing is every chapter ends with a list of script names and descriptions. In the text, he references these script names as well. That way, when you download the code you have a straight reference to the sample you should be running. Ive used the (extremely poor) naming convention of demo001.sql, demo002.sql and so on. Next book theyll all have names and Ill be referencing exactly like he did. Very nice. The attention to detail, the simplicity of presentation (I dont care what level of Oracle user you are you will be able to read this book and get it). If you are advanced (ok, Ill put myself into that category), youll learn things you did not know before. If you are beginner, youll know lots more than some advanced people after reading it. The surprising thing? It isnt that hard. Well, it wasnt to me anyway maybe the math background I have helped. You do not need 10 years of experience with Oracle to get this stuff, and if you have 10 years of experience with Oracle you will get new knowledge you never had. Im on my second scan of it re-reading things that I didnt fully absorb. What Ill be doing lots in the future is referring to it. I got the gist of everything, I know where to go when I need to explain why. Or maybe Ill just post the link to the book. And remember, this is I of III, two more to come

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