Chapter 14. Troubleshooting

When trouble strikes in your Oracle database, there are many places to turn for clues about what is causing the problem. The approach you take to troubleshooting the database will depend, in part, on whether a few users complain or you get hundreds of phone calls and e-mail messages from irate users.

The alert log file can give you clues about global database errors, and the system trace files can tell you about problems with the background processes. When individual users are having problems with their sessions, and the error messages they are receiving in their SQL*Plus session aren't very descriptive, the user trace files may provide additional clues to the problem.

For Oracle9i, you can also use the Event Manager in Oracle Enterprise Manager (OEM) to automatically notify you of problems or potential problems, such as when disk space is close to running out. In Oracle 10g, the Advisory infrastructure in conjunction with the web-based Enterprise Manager Database Control provides similar functionality.