Performance tuning approach
Cary Millsap, in his book Optimizing Oracle Performance, describes a performance tuning methodology called "Method R". The following are the steps that Method R proposes:
1. Select the user actions for which the business needs improved performance.
2. Collect diagnostic data that will identify the cause of performance degradation.
3. Implement the change and measure the impact. If there is no performance gain then suspend performance improvement activity.
4. Go to step 1.
Performance improvement activity is not only related to the database but could be related to any of these areas — application tuning, operating system tuning, network tuning, I/O tuning, SQL tuning, and database tuning.