Figure 2-14 illustrates various levels of Oracle-focused time classification. This information could represent the results of an entire Oracle system over a one-hour period. It could also represent the results of profiling a single transaction, a single session, or perhaps a group of sessions. Regardless, the diagnostic and communication aid provided by such time classification are significant. The benefit increases when combined with a little information, such as available CPU capacity, workload activity, and a response-time graph.

Notice there are a number of classification levels, allowing you to pick the most appropriate for the given occasion. When combined with Oracle's percentage of the operating system CPU consumption, level 2 provides insights into the CPU subsystem utilization, without running a single operating system command! You'll learn more about this in Chapter 5. When talking with management, I usually work at level 3, and if the managers can grasp more detail, I'll go to level 4. When talking with DBAs and devising solutions, I'll be working at level 5.

The ability to summarize complexity to enable a broader understanding is very desirable. The more senior the DBA, the more he tends to realize this challenge and value this skill. Acquiring technical prowess is required, but if you want to continue moving forward in your career, you must be able to transform very complex topics into seemingly very simple concepts. This is where ORTA and, more specifically, time classification shine.