Ok I understand that. But my another question is when I'm putting massages in smaller transactions (e.g. 50 000 at once) the problem is the same. JBoss messaging allocates memory and doesn't free it until last message is delivered to recipient. In other words when I put 600 000 messages in separate transactions (50 000 messages each) the problem is the same. Only solution would be committing next next transaction only when those committed in previous one were all delivered (which means that whole allocated memory was released). View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4255245#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...