exclusive
The exclusive property is available for queues only (not for topics), and cannot be used with global queues.
When exclusive is set for a queue, the server sends all messages on that queue to one consumer. No other consumers can receive messages from the queue. Instead, these additional consumers act in a standby role; if the primary consumer fails, the server selects one of the standby consumers as the new primary, and begins delivering messages to it.
You can set exclusive using the form:
exclusive
Non-Exclusive Queues & Round-Robin Delivery
By default, exclusive is not set for queues and the server distributes messages in a round-robin—one to each receiver that is ready. If any receivers are still ready to accept additional messages, the server distributes another round of messages—one to each receiver that is still ready. When none of the receivers are ready to receive more messages, the server waits until a queue receiver reports that it can accept a message.
This arrangement prevents a large buildup of messages at one receiver and balances the load of incoming messages across a set of queue receivers.