The application designer needs to set performance expectations of the application at the design phase. Then during design and development, the application designers should consider which Oracle features can benefit the system. This manual describes some of the performance implications of the various Oracle features, and you can use this information to determine if a particular feature will enhance the performance of your application.
By designing a system to perform well, you can eliminate cost and frustration later in the life of the application. Figure 1 - 1 and Figure 1 - 2 illustrate the relative cost and benefits of tuning during the life of an application. As you can see, the most effective time to tune is during the design phase. Tuning during design gives you the maximum benefit at the lowest cost.
Figure 1 - 1. Cost of Tuning During the Life of an Application
Figure 1 - 2. Benefit of Tuning During the Life of an Application
Chapter 2, "Effective Application Design", describes some of the performance enhancing features you can use to ensure your application meets its designed performance goals. Of course, even the performance of well designed systems can degrade with use. This manual also describes a strategy for identifying and dealing with various performance bottlenecks.