Performance testing should be a major part of the upgrade test plan. Internal and configuration changes (for example, in query optimization and using OS threads) can cause query performance differences between Ingres versions.

At worst, a new release of Ingres should perform no slower than the previous version when run on the same hardware. At best, there should be a performance benefit when upgrading to a newer release.

Performance testing should always be done against data volumes that would be found on the production system.

If performance is found to be worse than the previous version, compare the table structures and indexes and QEPs from the slow queries. If there is no apparent difference, report the problem to technical support.

For more information on QEPs, optimizer statistics, and performance tuning, see the Database Administrator Guide.