After upgrading to a new version of the database server and backing up the new server, you can tune the server to maximize performance. If your queries are slower after the upgrade, find out what changed that affects your configuration and adjust your configuration and queries as necessary:
- Compare the default values in the new onconfig.std file to values in your previous installation, and make any necessary adjustments (For information about new and changed configuration parameters, see New configuration parameters and Configuration parameters that have been changed or removed in the IBM Informix Migration Guide.
- If you created sample queries for comparison, use them to analyze the performance differences between the old and new database servers and to determine if you need to adjust any configuration parameters or the layout of databases, tables, and chunks.
- If you changed your applications, check to see if the changes led to slower performance.
- If you changed your hardware, operating system, or network settings, determine if you need to adjust any related settings or environment variables.
- Make sure that you ran necessary update statistics after upgrading. For more information, see Completing required post-migration tasks in the IBM Informix Migration Guide.
More tips and answers to frequently asked questions are in the Frequently asked questions (FAQs) about IBM Informix section of the Version 11.70 Information Center.