Here’s a good way to test performance of your database and the machine it’s running on, especially if there is lot of business logic in the database itself – use Apache JMeter. It’s an open source Java desktop application that allows you to simulate load on server.
What you need to do is prepare a test system, a stack of SQL statements each JMeter thread (session) will execute and a set of variable values to use in those statements, when needed. After that, you should download and install the JMeter, create a new test plan and start testing. There is a good explanation with screen shots on how to do that at this blog post, so I won’t explain this in more detail. We followed the instructions and set up the tests with no problem, just replaced MySQL with Informix.
Remember, there’s no rollback implemented whatsoever, so if your test changes data, you should execute some code manually that’ll take the database in original state, or restore it from previous backup.