Specifying Queues

The queue element has several configuration parameters that control the following:

• A queue can be enabled or disabled. If it is enabled, it can be active or inactive.

When a queue is enabled, it can accept transaction requests. However, it can only allow the Queued Transaction Scheduler to execute transactions when it is active.

When a queue is disabled, it can still accept transaction requests. However, no transactions can be executed by the Queued Transaction Scheduler, even if the queue is active. A disabled queue must be enabled to make its requests available for execution; however, those transactions can only be processed during an active period.

The queue’s startup state can be configured (see The initial-state Attribute). However, an administrator can explicitly enable or disable a queue from the Queue List web page (see Requesting the Queue Reports).

• A queue can be configured to be active only during specified periods (see The active-interval Attribute). An active queue supplies transactions to the Queued Transaction Scheduler. An inactive queue only accepts transactions, but it does not allow Queued Transaction Scheduler to execute them until it becomes active. An active queue must also be enabled to process its transactions.

• A queue can be required to wait until other queues have either started or finished their transactions (see The previous-queues Attribute).

• A transaction can have a priority assigned to it within a queue (see the queue-priority parameter in Queuing Query Parameters).

Transaction priorities are 1 through 5, highest to lowest, which can be designated by the incoming request. Transactions assigned the same priority within a queue are processed first in, first out. If no priority is assigned, it defaults to 3.

• A transaction can be executed when the previous transaction is completed, after all previous transactions have started, or must execute even if previous transactions are not able to run. Execution criteria is applied to each priority group (see The scheduling-option Attribute).

• A hold can be placed on individual transactions within a queue or on every transaction in the queue. A hold will persist each time Arbortext Publishing Engine starts. Refer to The Transaction List Page and The hold-all Attribute for information.

• A transaction can be executed ahead of all other transactions in the system, overriding any other configuration settings that might prevent it.

• The number of queued transactions allowed to execute simultaneously overall is controlled by a global parameter maxConcurrentQueuedTransactions (described in The Global Active Transaction Parameters) and by the max-concurrent-transactions queue attribute for individual queues (described in The max-concurrent-transactions Attribute).

• The number of Arbortext PE sub-processes allocated simultaneously for processing queued transactions within a pool is controlled by the maxConcurrentQueuedTransactions parameter, described in The maxConcurrentQueuedTransactions Attribute.

• An Arbortext PE sub-process pool can be configured to be a dedicated queuing pool, meaning it only accepts queued requests. See Specifying a Dedicated Queuing Pool.

Refer to The e3config.xml Configuration File for more information on how to change attributes.