XMS supports
two modes of message delivery.
- Persistent messages are delivered once and once only. A messaging
server takes special precautions, such as logging the messages, to ensure
that persistent messages are not lost in transit, even in the event of a failure.
- Nonpersistent messages are delivered no more than once.
Nonpersistent messages are less reliable than persistent messages because
they can be lost in transit in the event of a failure.
The choice of delivery mode is a trade-off between reliability and performance.
Nonpersistent messages are typically transported more quickly than persistent
messages.