The Progress OpenEdge JMS Adapter supports a DISCARDABLE message delivery mode. For non-transacted Pub/Sub sessions, DISCARDABLE delivers all messages to subscribers that are keeping up with the flow of messages, but drops the oldest messages waiting for lagging subscribers when new messages arrive, under any of the following conditions:

• When the message server's internal buffers for that subscriber session are full
• When a neighbor cluster member containing a Topic subscription is unavailable and a subscriber is located on the other cluster member
• When an intended durable subscriber is unavailable

An application controls message delivery mode using the publish procedure and the setDefaultPersistency procedure.