We have an application deployed in WL5.1SP9 that posts a large number of messages to a topic very regularly. These messages are only of interest for about 10 seconds, and are thus, non-persistent.

Because of the large number of messages, the server is running low on memory, and no further messages are being produced.

How long does a non-persistent message exist for before being cleared/deleted. Is there anyway of changing this to a user defined figure, ie. 10 seconds? Or do we just have to throw more memory at it!

I assume that once a message has been consumed by all the subscribers, it will be marked for deletion, but what happens if there are no subscribers?

I know there is a JMSExpiration on the header file, but I believe this is only applicable to persistent messages.