A number of excellent white papers and books detail the wait event views, so there is no need to repeat that information here. But I will summarize the views with some actual sample script output to highlight important details.

You may also want to take a look at the v$event_name view, which lists all the wait events available for a specific Oracle release. It is also a great quick reference for the parameter values and the event classifications.

I like to start my 3-circle analysis by focusing on the Oracle system. Central to the Oracle response-time analysis is a good understanding of what Oracle processes are waiting for, such as a block, a buffer, a latch, or an enqueue. From an all-session or a system-level perspective, the central wait event view is v$system_event. When looking at v$system_event over an interval of time, you get a broad understanding of the Oracle wait situation.