Hi:
I am in the process of evaluating the use of Hibernate for a call center application that would have close to 250 concurrent users doing mainly select operations (quering information) on close to 100 tables.

The expected no. of records in the db is likely to be 100 Million.

We have decided to use Struts for the Presentation layer of our application.

We've developed a small PoC for Hibernate on some of the most complicated scenarios we envision in the application and are convinced that it works well. However, there is no way for us to validate whether Hibernate is scalable enough to support 250 odd concurrent users and if so what is the performance impact it would have. Our biggest requirement is on the Performance front considering it's a call center application.

An early response and help from all of you who have used this would be of utmost importance.

Thanks.

Why can't you simulate 250 users with 100 million test records to find out? This should be a straightforward task for something like JMeter or Mercury Interactive tools, and you'd be well served to run a full PoC load test before taking anyone else's word for it.

There simply are too many variables to guess at otherwise (these questions are rhetorical):
* What are the details of your server and network architecture?
* What do your top 10 queries look like and how long do they take to run?
* What kinds of business logic must execute between the requests and responses?
* Do you have any syncronized or locking operations?
* Are you interfacing with any other systems? If so, in what part of the request process are they accessed?
* What's your user load profile look like?

And this is just scraping the surface. Seriously, set up some load tests and judge for yourself end-to-end, and bring in JBoss if you really want to cover your bases.

Scott