[rabbitmq-discuss] Exchange performance

[Marek Majkowski]

On Fri, Jun 17, 2011 at 12:41, Max C <maxence.cordier at gmail.com> wrote:
> I have two questions I'd like to ask about exchanges.
>
> What happen to a message published to an exchange if no queue is
> suscribed to that exchange ?

Usually it's discarded.
There are two exceptions.
 a) look at the immediate/mandatory message flags:
    http://www.rabbitmq.com/amqp-0-9-1-quickref.html#basic.publish
 b) look at 'alternate exchange' feature:
    http://www.rabbitmq.com/extensions.html#alternate-exchange

> In my application, I have a bunch of devices sendind data to a
> rabbitMQ broker. I'm wondering if I should use 1 exchange for all my
> devices, tagging messages with the name of the device which send
> them ? Or if I should use 1 exchange per device.

It all depends on how you want to use the messages. But 1 exchange
usually should do.
(and uses less resources than many exchanges :P)

Cheers,
  Marek