As good as the OWI is, it has a few issues and limitations. We would do you a disservice if we left them out of our discussion because being aware of them will help you better understand how OWI works and how to use it. In the next few sections are some of the issues and limitations of OWI not discussed elsewhere.
No CPU Statistics
We introduced response time tuning methodology in Chapter 1, which takes into account the service time. Service time is the CPU time, but OWI does not offer the CPU time information. However, this information can be obtained from the V$SESSTAT view.
No End-to-End Visibility
One thing you may hear a lot from software vendors that sell proprietary performance monitoring tools is that OWI is limited to ...