How should an application be set up to subscribe to multiple topics?
If you want to listen to N topics, using N subscribers and N sessions gives you concurrency up to N simultaneous threads of execution provided you have that many threads to work with. N subscribers and 1 session serializes all subscribers through that one session. If the load is heavy they may not be able to keep up without the extra threads. Also, if you are using CLIENT_ACKNOWLEDGE, N sessions gives you N separate message streams that can be individually recovered. Having 1 session crosses the streams giving you less control. Note that unlike earlier versions of WebLogic JMS, version 6.1 on the server side efficiently uses a small, fixed number of threads independent of how many client sessions there are.
A. If you want to listen to N topics, using N subscribers and N sessions gives you concurrency up to N simultaneous threads of execution provided you have that many threads to work with. N subscribers and 1 session serializes all subscribers through that one session. If the load is heavy they may not be able to keep up without the extra threads. Also, if you are using CLIENT_ACKNOWLEDGE, N sessions gives you N separate message streams that can be individually recovered. Having 1 session crosses the streams giving you less control. As of version 6.x or later, WebLogic JMS on the server side efficiently uses a small, fixed number of threads independent of how many client sessions there are.
