You need to remember that these are not hard real-time deadlines. All the specification says is that if the transaction hasn't rolled back by the time the time-out goes off, it'll be rolled back automatically. But it doesn't say that a transaction will be rolled back immediately. There are trade-offs to be made: immediacy can imply more overhead, whereas "sometime afterwards" may mean you don't see the timeout happen for a while, but there's less overhead. That's why we support a couple of modes, to give flexibility. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4055697#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...