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Working with alias queues

 

An alias queue provides a way of referring indirectly to another queue. The other queue can be either:

• A local queue (see Defining a local queue).

• A local definition of a remote queue (see Creating a local definition of a remote queue).

An alias queue is not a real queue, but a definition that resolves to a real (or target) queue at run time. The alias queue definition specifies the target queue. When an application makes an MQOPEN call to an alias queue, the queue manager resolves the alias to the target queue name. An alias queue cannot resolve to another alias queue.

Alias queues are useful for:

• Giving different applications different levels of access authorities to the target queue.

• Allowing different applications to work with the same queue in different ways. (Perhaps you want to assign different default priorities or different default persistence values.)

• Simplifying maintenance, migration, and workload balancing. (Perhaps you want to change the target queue name without having to change your application, which continues to use the alias.)

For example, assume that an application has been developed to put messages on a queue called MY.ALIAS.QUEUE. It specifies the name of this queue when it makes an MQOPEN request and, indirectly, if it puts a message on this queue. The application is not aware that the queue is an alias queue. For each MQI call using this alias, the queue manager resolves the real queue name, which could be either a local queue or a remote queue defined at this queue manager.

By changing the value of the TARGQ attribute, we can redirect MQI calls to another queue, possibly on another queue manager. This is useful for maintenance, migration, and load-balancing.

• Defining an alias queue
  

• Using other commands with alias queues
  

 

Parent topic:

Administering local WebSphere MQ objects

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