[rabbitmq-discuss] Message presence notification

Marek Majkowski majek04 at gmail.com
Thu Feb 23 11:21:16 GMT 2012

On Thu, Feb 23, 2012 at 09:51, Cermak, Marek <Marek.Cermak at honeywell.com> wrote:
> in our scenario we use two different connections to rabbitmq server – one is
> using a slow and permanently open link the second is very fast but opens
> only on demand and should be closed once it is not in use.
> These two connection we want to use for consuming messages from many (tens,
> hundreds) queues in the following way
> 1.       open the connection on a slow link and "watch" the queues;
> 2.       once there is a message in one of the watched queues, the client
> receives a notification (no message) from rabbit;
> 3.       client opens the fast link, consumes available messages from queues
> and closes  the link;
> 4.       back to #2.
> How can we achieve this with AMQP (0.9.1 or 1.0) ? Can we do it with no
> RabbitMQ protocol extension?

Why not just send two messages? One to a real queue, and another
one, with no payload, to a queue called 'notifications'.

In this case, whenever there is a new message coming to 'notifications' queue,
the consumer will know that there should be another, big, message in some
other queue.

Does it make sense?

> I was thinking about channel.basicQoS(0) but what would I get in that case?

Spec says:

> May be set to zero, meaning "no specific limit", although other
> prefetch limits may still apply.


More information about the rabbitmq-discuss mailing list