[rabbitmq-discuss] Problems installing LVC exchange

Rob Woolfson rob at bsdsoftware.co.il
Thu Jul 5 14:27:55 BST 2012


Is the issue the number of messages that could be sent, because with a
large number of bindings I will receive a large number of messages to
the queue in a direct exchange too?

If I understand you correctly the problem is a new routing key could
match one or more messages stored, as opposed to in a direct exchange
where once it finds a match it can stop searching as it will match one
and only one message.

This is a problem if there are many potential routing keys especially
if they are segmented (not sure what to call it) x.y.z.a.b.c then
there is a lot more checking todo.  How much of a problem is this

My problem is that I want to use this to track the status of a number
of different things.  With a topic style routing key I can send all
status message to a single exchange and have all process requiring to
know the status of a particular other process consume only the
relevant messages.  This is easiest with a topic exchange, anything I
do with a direct exchange will require more and possibly many more
exchanges and or parsing of complex routing keys.

On Thu, Jul 5, 2012 at 3:58 PM, Simon MacMullen <simon at rabbitmq.com> wrote:
> Not at the moment, I think because it's not completely obvious what it
> should do.
> The direct-exchange case is obvious: store a last message for every routing
> key that is ever published, and then look up the routing key when a new
> queue is bound.
> But in the topic case if we do that then we would have to check each stored
> message and send it to the new queue if it matches the new routing key. So
> the queue could conceptually get a whole load of messages sent. Does this
> seem like a reasonable thing for it to do?
> Cheers, Simon
> On 05/07/12 11:20, Rob Woolfson wrote:
>> Is there a way to change it to a topic exchange instead of a direct
>> exchange?
>> On Wed, Jul 4, 2012 at 5:11 PM, Simon MacMullen<simon at rabbitmq.com>
>>  wrote:
>>> On 04/07/12 15:08, Rob Woolfson wrote:
>>>> You need to change this in the readme:
>>> Good point; done.
>>> Cheers, Simon
>>> --
>>> Simon MacMullen
>>> RabbitMQ, VMware
> --
> Simon MacMullen
> RabbitMQ, VMware

Rob Woolfson - CTO

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