Queues
A WebSphere MQ queue is a named object on which applications can put messages, and from which applications can get messages. Messages are stored on a queue, so that if the putting application is expecting a reply to its message, it is free to do other work while waiting for that reply. Applications access a queue by using the Message Queue Interface (MQI), described in Introducing the Message Queue Interface.
Before a message can be put on a queue, the queue must have already been created. A queue is owned by a queue manager, and that queue manager can own many queues. However, each queue must have a name that is unique within that queue manager.
A queue is maintained through a queue manager. In most cases, each queue is physically managed by its queue manager but this is transparent to an application program. WebSphere MQ for z/OS shared queues can be managed by any queue manager in the queue-sharing group.
To create a queue we can use WebSphere MQ commands (MQSC), PCF commands, or platform-specific interfaces such as the WebSphere MQ for z/OS operations and control panels.
We can create local queues for temporary jobs dynamically from your application. For example, we can create reply-to queues (which are not needed after an application ends). For more information, see Dynamic queues.
Before using a queue, open the queue, specifying what you want to do with it. For example, we can open a queue for:
- Browsing messages only (not retrieving them)
- Retrieving messages (and either sharing the access with other programs, or with exclusive access)
- Putting messages on the queue
- Inquiring about the attributes of the queue
- Set the attributes of the queue
For a complete list of the options that we can specify when you open a queue, see the description of the MQOPEN call in the Application Programming Reference.
- Types of queue
- Attributes of queues
- Remote queues
- Alias queues
- Model queues
- Dynamic queues
- Transmission queues
- Initiation queues
- Dead-letter (undelivered message) queues
- System command queues
- System default queues
Parent topic:
WebSphere MQ objects
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