Shift queue is extended from Drupal system queue with two new features:
Disable the processing of a particular queue
This feature allows to stop the processing a queue.
Set maximum failed processing attempts
Originally in Drupal system queue, when a queue item is processed with exception, it will be processed again until it is processed completely.
This feature allows to retry in a limited configurable times and if it still get problem, this item will be moved to a separate queue called: 'ORIGINAL_QUEUE_NAME:failed'.