Application developers should tune applications prior to production use. Tuning applications often produces dramatic performance improvements. System administrators perform the remaining steps in the following list after tuning the application, or when application tuning has to wait and you want to improve performance as much as possible in the meantime.
Ideally, follow this sequence of steps when you are tuning performance:
Tune your application, described in Chapter 2, Tuning Your Application
Tune the high availability database, described in Chapter 6, Tuning for High-Availability
Tune the Java runtime system, described in Chapter 4, Tuning the Java Runtime System
Tune the operating system, described in Chapter 5, Tuning the Operating System and Platform