A message point is associated with a messaging engine and
holds messages for a bus destination.
A message point is the general term for the location on a messaging
engine where messages are held for a bus destination. A message point
can be:
- A queue point
- A publication point
- A mediation point (which is a specialized message point)
For point-to-point messaging, the administrator selects one bus
member, which can be an application server
or
server cluster, to hold the messages of the queue destination.
This action automatically defines a queue point for each messaging
engine in the assigned bus member.
- For a queue destination assigned to an application server, all
messages sent to that destination are handled by the messaging engine
of that server, and message order is preserved.

- For a queue destination assigned to
a server cluster, there is a separate message point for each messaging
engine in the cluster. The message points partition the destination
in the same way that a WebSphere® MQ
cluster partitions a clustered queue. Multiple messages addressed
to a such a partitioned destination are handled by any messaging engine
in the cluster, but an individual message is handled by only one
engine.

The messages
of the destination are split between the separate message stores for
the messaging engines. This configuration has the disadvantage that
message order cannot be preserved, but has advantages:
- Multiple producers or consumers can be deployed across the same
server cluster and messaging operations are handled locally by the
messaging engine of a cluster member.
- Cluster monitoring can detect the failure of a messaging engine,
and the surviving engines within the cluster can take over the message
stores containing the permanent state for the failed engine.
If message ordering must be preserved, follow the rules described
in Message ordering.
For publish/subscribe messaging, the administrator configures a
topic space destination, but does not need to assign a bus member
for the topic space. A topic space has a publication point defined
automatically for each messaging engine in the bus.
Message points can be remote from the application
which is producing to or consuming from the bus destination. In other
words, message points can reside on a messaging engine other than
the messaging engine to which the application is connected. In this
situation the message point is represented at runtime by a remote
message point on the remote messaging engine.
By monitoring message points and remote message
points, you can fully analyze and resolve problems arising from distributed
application messaging. For example, you can:
- Determine the state of a specific message request.
- Determine the location of a specific message.
- Examine message queues to determine if messages have been sent
or received.
- Free or delete message requests that have become locked.
- Delete or move messages from remote message points.