Guideline for Configuring the Delivery Mode (JMS Only)

Delivery mode indicates the mode in which messages are delivered. It is only supported for JMS connections.

For a JMS transport session, delivery modes vary according to different service types:

Regarding Publication Service, the following delivery modes are supported:
- Persistent: in general, a message marked persistent is available to a JMS client even if the EMS server goes down. Persistent messages are held in secondary storage in the server and have guaranteed delivery when they are sent to a topic that has durable subscribers.
- Non-persistent: a message marked non-persistent is not available to a JMS client if the EMS server goes down. These messages are never written to persistent storage.
For Subscription Service and Request-Response Service, the Delivery Mode option is available only when the Connection Factory Type is Topic. For details about connection factory types, see "JMS Sessions" in Session Reference.
The following delivery modes are supported:
- Durable: The JMS server stores messages sent to the service even when the service is down. When the service recovers, the service receives the stored messages.
  If a topic has no durable subscribers, no subscribers require messages to be resent in the event of a server failure and therefore messages do not have to be saved. Performance is improved because disk I/O is not required.
- Non-durable: The service is not registered with the JMS server. The JMS server does not hold messages sent to a non-durable service when the service is down.

For more information about delivery modes, see TIBCO Enterprise Message Service User’s Guide.