Queue destinations
A queue destination represents a message queue and is used for point-to-point messaging. A service integration queue destination is localized in a particular bus member (application server or cluster of application servers). When a producer sends a message to the queue destination, the service integration bus delivers the message to a messaging engine in that bus member. The messaging engine then delivers the message to a consumer. If necessary, the messaging engine queues the message until a consumer is ready to receive it..
The term "queue" is used, as an abbreviation for "queue destination", to refer to a bus destination configured for point-to-point messaging.
Applications use API-specific artifacts such as a JMS queue, which encapsulates the name of a queue destination, but are unaware of the existence of the service integration destination or of the bus it is configured on. For more information, see How JMS destinations relate to service integration destinations.
The administrator assigns a queue destination to only one member (an application server or server cluster) of the service integration bus, or an IBM MQ server. The messaging engine in the bus member hosts the message point for the queue, known as a queue point. The queue point is the location where messages for the queue are stored and processed.
If the bus member has more than one messaging engine, the queue destination is partitioned across the messaging engines. Each messaging engine has a separate queue point. Each message sent to a queue destination is held on only one of the destination queue points: the message is not duplicated across queue points. Each messaging engine handles a share of the messages arriving at the destination so that the messaging workload is balanced across all messaging engines in the cluster bus member.
When a queue is partitioned across messaging engines, to avoid orphaning messages, each queue point must have an associated consumer. By default a consumer is associated with one queue point per session but a consumer can be configured to consume from more than one queue point.
An application can also create its own temporary queues, which appear temporarily in the list of queue points for the messaging engine, but usually need no administrative intervention.
When a destination is configured on a bus member that is an IBM MQ server, the destination has a single queue point called an IBM MQ queue point. This IBM MQ queue point is an IBM MQ queue on the IBM MQ queue manager or queue-sharing group that the IBM MQ Server represents. For more information about IBM MQ queue points, see related concepts.
Related:
JMS queue resources and service integration Workload sharing with queue destinations Permanent bus destinations Create a queue for point-to-point messaging Configure bus destination properties