[rabbitmq-discuss] Help defining appropriate queue model

Fri Mar 18 16:31:50 GMT 2011

Fabio,

> I've worked a bit more on my tests by now and another doubt has come
> up. Is there any way to make messages exchanged through x-lvc
> persistent? The scenario I'm exercising is: the publisher sends a
> message to the broker, it is consumed a few times, the broker dies
> and starts up again, then a few new consumers try to receive the
> message. I can't get this to work yet.

Right, at the minute the last values are transient. It probably wouldn't 
take much coding to make it save things to disk for durable exchanges.

> From what I've seen in my tests, the exchange only works with
> exclusive queues, is that correct? I've tried creating a named,
> durable queue for all consumers to read from, but in this case the
> message can only be consumed once. On Thu, Mar 10, 2011 at 10:36,
> Fabio Margarido <fabiomargarido at gmail.com
> <mailto:fabiomargarido at gmail.com>> wrote:

It will work with any queue.   However, if you have many consumers to a 
queue, each message will be delivered to one consumer only -- that's the 
semantics of AMQP queues.  So, in your case, I think you want a queue 
for each consumer anyway.

Michael

> I've worked a bit more on my tests by now and another doubt has come
> up. Is there any way to make messages exchanged through x-lvc
> persistent? The scenario I'm exercising is: the publisher sends a
> message to the broker, it is consumed a few times, the broker dies
> and starts up again, then a few new consumers try to receive the
> message. I can't get this to work yet.
>
> From what I've seen in my tests, the exchange only works with
> exclusive queues, is that correct? I've tried creating a named,
> durable queue for all consumers to read from, but in this case the
> message can only be consumed once.
>
> Is there something I'm missing?
>
> Thank you.
>
> On Thu, Mar 3, 2011 at 22:07, Michael Bridgen <mikeb at rabbitmq.com
> <mailto:mikeb at rabbitmq.com>> wrote:
>> Fabio,
>>
>> Aces, glad to hear it's working for you thus far.
>>
>> On this:
>>
>>> Just a final question: the previous README file on github said
>>> something about including the plugin on the main RabbitMQ code,
> but I
>>> figured this had been written some time ago because it mentioned
>>> version 1.7.1. Is this still in your (and RabbitMQ developers)
> plans?
>>> Best regards.
>>
>> -- I was referring to the exchange plugin mechanism overall, on
> which I was
>> finishing (largely other people's!) work at the time.  That
> mechanism has
>> been in mainstream rabbitmq since then, and has changed a bit,
> but is pretty
>> stable.
>>
>> The Last Value Caching exchange will likely stay a plugin for the
>> foreseeable future, rather than being baked into rabbitmq-server.
> But if
>> you follow this list you'll know this is not the last word ..
>>
>> Michael
>>
>>>> Oh.  Looks like github's upload and download system is totally
> broken.
>>>> (I've now tried to upload it a few times).
>>>>
>>>> I've attached the ez so it can be stopped by mail filters
>>>> instead.
>>>
>>> Hi Michael. Sorry for the extra trouble.
>>>
>>> I've now rebooted my RabbitMQ server and run a few basic tests
>>> and everything seems to be working as expected. Thank you again
>>> for all your help and your work on the plugin. I'll keep building
>>> my test scenarios and I'll let you know if something else comes
>>> up.
>>>
>>> Just a final question: the previous README file on github said
>>> something about including the plugin on the main RabbitMQ code,
> but I
>>> figured this had been written some time ago because it mentioned
>>> version 1.7.1. Is this still in your (and RabbitMQ developers)
> plans?
>>> Best regards.
>>
>>
>
>