Phat is just a tool. A hammer in your hand will not make you a carpenter. So a tool alone will not bring you very far in solving and analyzing performance problems. You need some logic thinking, and a method will be nice. That last one is the most easy:
The thirst thing to read is YAPP (at http://www.oraperf.com); ‘Yet Another Performance Profiler’ by Anjo Kolk, Shari Yamaguchiand and Jim Viscusi. It tells a bit how to look into the database, and how to act on certain findings. This paper is today’s standard for Oracle performance analysis.
Yapp is still not enough as a method. You need a little more, some kind of non technical procedure to avoid you will keep tuning forever. Method-R looks like a suitable one. But there are others also.
Oracle’s approach to tuning
This looks a bit like Method-R. It tells you what to focus on, preventing you will be tuning forever. Things are never perfect, but there should be a point where you have to stop analyzing and tuning because it’s acceptable.
Yapp & timing
Reading Ora9iR1_timing_anjokolk is the next thing to do, when are have gotten a bit familiar with Yapp. When you really get deep into timing it’s important to know a few limitations. (also to be found at http://www.oraperf.com)