[openamq-dev] round-robin queues

[Esteve Fernandez]

Hi all, is there way to dispatch messages only once if two queues are bound to 
the same exchange with similar arguments? I guess it's easier to develop this 
question with an example scenario:

- a headers exchange "library"
- A, B and C are different boxes, each having a consumer and a queue bound 
to "library" with similar (but different) arguments:

* A has a queue bound to "library" twice with the following headers:
o type: magazine
o type: book

* B has a queue bound to "library" twice with the following headers:
o type: book
o type: dvd

* C has a queue bound to "library" twice with the following headers:
o type: dvd
o type: magazine

when, for example, a message with "type: magazine" is sent to "library", both 
A and C receive them, as expected. Is there a routing scheme that allows to 
do round-robin at the queue level, not at the consumer level? That is, if 
such message is sent, either A or C receives it, but not both.

The other approach that I came up with is to have a queue for each type 
(magazine, book and dvd), the problem is that I might end up having a lot of 
queues if I add more types. When Pieter responded to Terry, he said that 
queue creation is cheap, but that creating so many queues might be slower 
than having one queue per client.

Cheers.