Thanks for the reply. I used the kit from this page: http://www.jboss.org/community/docs/DOC-11980 This way I was able to make the benchmark run. I spend a lot time in playing with the connections pools. My latest configuration was 2000 connections on the mysql-server site and about 1000 connections on the jboss site. But I always had the problems I described. Why do I need a connection for every request? Perhaps this problem only occurs when combining JBoss, MySQL and Windows ;) View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4224164#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...