anonymous wrote : Still interesting that the heap size doubles just because i have a different ISOLATION level. If you are using 'NONE' then no lock object is being created for each node. I think there won't be significant differences between other isolation levels (except serialiable, which I should be quite memory-efficient due to same reasons as NONE) View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4166345#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...