I first wrote about my 3-circle analysis method back in 1994 on a flight from Los Angeles to Sydney. I actually remember writing the paper, entitled "Total Performance Management,"6 in which I called it the holistic problem isolation method. It seemed so natural to the way I approached firefighting that, at the time, I didn't grasp its simple power. Over the years, many of my students have written me about how this one method revolutionized their performance analysis. Strangely, of all my work, this is the very least technical, but perhaps that's the genius of the method.

Take a close look at Figure 1-1, which illustrates the 3-circle analysis technique. In a nutshell, the database server is divided into three subsystems: Oracle, application, and operating system. Each subsystem is diagnosed separately and then in combination. There will be a clear overlap in resource consumption and contention. If the problem resides with the database server, the overlap is the current performance problem. It's that simple.

Figure 1-1. As unbelievable as it may seem, OraPub's 3-circle analysis method will guide you toward pinpoint diagnosis, reduce your chances of making a mistake, help you determine multiple solutions, help you structure your analysis, and help you effectively communicate your findings.