Oracle 10g slow performance on first query We have an application which we recently upgraded and is having bad performance issues. Any ideas would be much appreciated.

The main issue is windows taking ages (minutes) to open because the initial query to fill their list boxes is taking so long. The second time a user opens the window its fine.

We would expect this to be application cacheing but we don't think so. We see similar problems using Crystal Reports and using command line SQL queries.

We have increased the RAM available to the database.

Another part of our business has a slightly different version of the same application and database and doesn't get this problem.

The time to complete a query can be 30 minutes for the first time in a session and 30 seconds for subsequent executions.
The usual reason for such issues is that the first execution of the query requires physical reads to fetch the required blocks from disk, and the second and subsequent executions find that they are already cached.

You can test this by running the queries from SQL*Plus (and timing them) prior to first opening these windows of which you speak, to see if that affects performance.

If you can come back with comparison of the timings when running the queries through SQL*Plus and then through the application it would help further analysis.