I looked through the documentation and some of the discussions, but didn't see an answer for this question:
Does HornetQ implement Message Selectors on the server side or client side? I have a topic which spews lots of realtime data, but various clients are usually only interested in a subset of that data. It seems that using a message selector would be helpful to reduce network traffic, but only if the HornetQ server performed the filtering before sending the data. Otherwise, it might be best to use multiple topics.
Filter is done at the server's side. We wouldn't do a network trip to the client and decide the client didn't want the data. As you said that would waste network resources.