Thank you for the quick reply. Two followup questions (one from the original post): - "if all of the data in a node ages out of the cache due to LRU, is the data removed from the cache and the node left in place, or is the node also removed"? - "but you do introduce the possibility of phantom reads (but this is allowed in R_R semantics anyway)." We're using READ_COMMITTED. That should prevent phantom reads, shouldn't it? View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4220955#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...