It was back in late 2005 or early 2006 when I was prompted by an Oracle magazine issue to buy the then best Oracle seller book of the year: Oracle Cost Based Fundamentals. When Amazon shipped me this book, I was really disappointed when I started browsing its content. The first question that came to my mind was: is this book speaking about an Oracle technology? You can imagine how much this question revealed my degree of Oracle ignorance by that time. To my defense I was working for a customer as a PL/SQL developer under Oracle 8i. My tasks were to faithfully transform business requirements into a technical requirements and then into a set of stored procedures. Oracle 8i was under Rule Based model while the book I bought explains fundamentals of Oracle Cost Based Optimizer. I was in such a situation that inevitably the content of this new book was not matching my interests. So I put it on hold.
Several years after, I started a new job where trouble shooting performance issues was a crucial part. The application was upgraded from 8i (Rule Based) to 10gR2 (Cost Based) and was suffering terrible performance problems. It was time for me to wake up both the book and my head from their hibernation. Degustation of the book content begins.
More than 4 years after I have started trouble shooting performance problems and particularly bad query execution time, I am still using and savoring the content of this unrivalled and unequalled book.
There are 14 chapters in this book; I am not going to tell you what chapter is must to read or what has most retained my attention. This is not a book to only read and re-read. This is a book to learn by heart. This is a book you should always have with you when trouble shooting queries bad execution time. This is a Swiss knife allowing a CBO dissection.
Simply put, this book is so that if, when speaking with an experienced Oracle tuning DBA-Developer, I came to realize that he still has not read this book then I immediately measure the gap he has to fill before he will start doing correctly his job (unless he has read the Performance Guide itself 
).
