[rabbitmq-discuss] Non-supported arguments in Queue.Declare

Simon MacMullen simon at rabbitmq.com
Fri Apr 15 16:45:50 BST 2011

On 15/04/11 15:44, Gavin M. Roy wrote:
> I wanted to check if there are any potential adverse effects of using
> custom arguments in a queue declaration. Specifically I am looking at
> adding three arguments to our queues:
> x-monitor: bit
> x-monitor-warn: int
> x-monitor-critical: int
> I've tested this on a non-production box and didn't notice any adverse
> effects but wanted to make sure I wasn't missing something. Will this do
> anything bad under-the-covers in Rabbit?

No. Arguments that are not recognised are ignored.

For the record, unrecognised arguments do not count towards exchange 
equivalence, so if you issue two otherwise identical queue.declares with 

x-monitor: true


x-monitor: false

then the second will go through and return the first queue, whereas if 
you do the same thing with arguments:

x-expires: 1000


x-expires: 2000

then the second queue.declare will fail.

Of course, you may not care about this.

> I did notice that the values show up in the Parameters section in the
> Management plugin Web UI in an less than ideal fashion.

What don't you like about it? :) It does wrap a bit much in the listings 
I suppose.

> Also, Is there a way to update arguments without deleting/redefining the
> queue?

No, afraid not.

Cheers, Simon

Simon MacMullen
Staff Engineer, RabbitMQ
SpringSource, a division of VMware

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