Hi, What is the expected behaviour of JBoss Messaging (JBM 1.0.1.SP4 on AS 4.0.5.GA) when one of several topic subscribers is very slow in processing messages? We are using non-persistent messages and non-durable subscribers with DUPS_OK_ACKNOWLEDGE. Messages are generated in this scenario at a rate of about 2000 msgs/sec. At first, other subscribers are not affected. But when after some time messages begin to be persisted into external store (Sybase), all clients get delayed messages at a very slow rate. After some time the database tables get cleaned out and the cycle begins again. Can someone please explain, how internal and external message store are used in this scenario? Is there a way to isolate other subscribers against a very slow or blocking one? Thanks for any suggestions. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4029372#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...