WAS v8.5 > WebSphere applications > Service integration > Bus destinations
Message points
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
- An alias destination
- 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, 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.
Applications can use an alias destination to route messages to a target destination in the same bus or to another (foreign) bus (including across a WebSphere MQ link to a queue provided by WebSphere MQ). By assigning an alias destination to a subset of the queue points of a partitioned queue destination, alias destinations can be used to restrict the queue points used by producing and consuming applications.
For publish/subscribe messaging, the administrator configures a topic space destination, but does not have 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 be 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, we can fully analyze and resolve problems arising from distributed application messaging. For example, we 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.
Subtopics
- Remote message points
A remote message point is a messaging engine runtime view of any message point associated with a remote messaging engine. Remote message points are dynamically created and destroyed when they are required by the bus; we do not have to configure them explicitly.
Related concepts:
Publish/subscribe messaging and topic spaces
Message ordering
Mediation points
Mediation handlers and mediation handler lists
Queue destinations
Related
Configure message points
Configure a message point
List message points for a bus destination
List message points for a messaging engine
List messages on a message point