[rabbitmq-discuss] RabbitMQ as a reliable message queue

Tue Jun 14 17:08:07 BST 2011

> Is it possible to use RabbitMQ as a reliable message queue? What I
> mean is to make it preserve the order of messages in queues even for
> non ack'ed durable messages.
> Putting non acked messages into the end of the queue just doesn't make sence.

Actually, it would be difficult to preserve the order in the case of
non-ack. Let's say you've got M1, M2, M3, M4 in the queue (like the
FAQ describes). If you have two consumers, and C1 is consuming M1 and
C2 is consuming M2. C1 finishes, acks M1 and starts consuming M3.
However, C2 fails and disconnects without acking M2, where should M2
go in the order? M3 is already being consumed. The only sane approach
is to treat M2 as a new submission and append it to the end of the
queue.

-J