Suppose that the host server and operating system are running smoothly at your site, and you have configured and tuned Oracle to run at the peak of perfection, but performance on your critical application is still poor. Unfortunately, this is not an uncommon occurrence. The solution is to tune the application by examining and tuning the SQL statements being executed.

SQL tuning is a subject that deserves a book of its own. In fact, there are several good books on the market that address tuning in much more detail than is available here. We urge you to check the sources listed in the appendix, Resources for the DBA. In this section, we’ll offer some brief advice and guidelines for tuning your SQL statements.