Non-durable subscribers

A non-durable subscriber is a message consumer that only receives messages that are published while the subscriber is active. Messages delivered while the subscriber is inactive are lost.

The information in this topic is relevant only when we are using publish/subscribe messaging over a IBM WebSphere MQ Version 6.0 queue manager.

If consumer objects are not deleted before or during the closing of the connection, messages can remain on the broker queues for subscribers that are no longer active.

In this situation, the queues can be cleared of these messages using the Cleanup utility provided with IBM WebSphere MQ classes for JMS Classes for JMS. Details of how to use this utility are provided in IBM WebSphere MQ Using Java. You may also need to increase the queue depth of the subscriber queue if there are large numbers of messages remaining on this queue.