Question

We have a basic Java EE app that runs under tomcat and maintains a connection pool to a SQL server database. We were having some data issues showing up only in production, so I created a testing tool that would simulate different numbers of users going through the system on different paths.

I’ve worked on this a bit and so the problem’s evolved as I chased it. Now the problem is this.

Ten user threads works perfectly. Twenty user threads and the log record that gets created when the user logs into the system never gets inserted for any of the 20 users. In fact, Hibernate 3.3 goes through the motions of inserting the record, but when I use the show_sql setting, the insert statement never shows up in the dump. Again this works perfectly with 10 users. And more puzzling, every once in a while it will work for one of the 20 users. 🙁

I’m using the JTDS driver, btw, to avoid the problems we kept finding with the MS one.

I am running SQL Server Express 2008 R2 on my local box with tomcat and running my test app in my eclipse IDE. Has anyone seen anything like this? Any ideas as to why hibernate might be locking after 10 users?

Answer 1

I believe the problem is that you cannot open enough sessions as you need (Because they are pooled)

• How do you open the session ?
• What size does your connection pool have?
• Do you always close the sessions?