Each VU must record data on DB?
I can record a script logged as ONE user and record data over ONE of my customers. Executing this script using 20 VU just the first one perform the real operation (data on DB).
The question is: should the 20 VUs record data in the DB to obtain realistic results? Is it needed to parameterize any logged user and any 'customer' (item over I perform operations) in the application?
Re: Each VU must record data on DB?
You will probably have to model your applications session handling in SCL - by default the OpenSTA recording process makes an attempt to deal with very basic cookie based session handling, anything else is left up to the tester to program in SCL.
How you do this is highly dependent on your Web application, its environment and setup.