As described in Chapter 46, performance tuning begins with design. In many cases, the core performance problem in a database application has been designed into the system. You may be able to identify the most resource-intensive parts of the application, focusing future tuning efforts on specific database parameters or SQL statements. This chapter, you will read case studies related to different performance problems and their resolutions. The case studies present three common problem areas—environmental issues, problem queries, and application architecture—from an application tuner’s perspective.