[rabbitmq-discuss] RabbitMQ Consistent Hashing Exchange
john.turner at thoughtforge.net
Thu Jul 4 11:48:53 BST 2013
I've added some comments inline. I'm very happy to help you with
requirements here so if a call would help let me know and I'll set it up.
Do you have a timeline for this feature?
On Wednesday, 3 July 2013 21:24:26 UTC+1, hyperthunk wrote:
> We've got an open bug to provide a 'message groups' feature like this and
> are hoping to get it ready for a feature release ASAP.
> Just out of interest, for your use-case, how would you expect failover to
> Do you want all future messages delivered to another random consumer?
> What about un-acked messages that were already delivered - we plan on
> redelivering these (Agree) - and how do you plan on explicitly
> terminating a group? (This is not a requirement. Groups should only be
> terminated by a connection closing either explicitly or due to failure)
> Would a special message (or header) given by the producer suit that
> purpose? (If people want this functionality I would suggest this is the
> best way. You might also consider giving the consumer the ability to
> terminate a message group but we don't have a specific use case for this.
> It might be something for future releases.)
> What about consumers that don't disconnect but indicate they'd like to
> stop processing that group of messages? (I referred to this above. I'd
> suggest you add this to a future release as it really is not a must have).Do you have consumers that want to recieve more than one group in parallel?
> (Absolutely) And what about producers that go away - do you close the
> group when they disconnect or keep it open indefinitely, or use a timeout? (I
> would keep it open indefinitely because multiple producers may be
> contributing messages to a single group. You have some challenges around
> clean up here though. It could be reasonable to say that when all messages
> in a group have been processed that the group closes after a timeout. When
> subsequent messages arrive the group is recreated.)
> None of those things are very clear to me from the activemq docs, so
> hearing from a real world user would be nice! :)
> > Hi All,
> > I'm very familiar with JMS and have used the GroupID extension to
> provide processing affinity to a single consumer. For further information
> on how this works see this ActiveMQ documentation:
> > This solves the following requirement:
> > * Messages are distributed to a queue with a GroupID header.
> > * The broker guarantees that messages with a specific GroupID (say
> '1234') will only be processed by a single consumer.
> > * If the consumer fails (i.e. the connection is broken or closed), the
> broker will allow another consumer to process messages with that GroupID
> > Using RabbitMQ and the Consistent Hashing Plugin does not not appear to
> solve the problem because if we are using static (durable) queues, the
> consumer failover mechanism needs to be implemented outside the server.
> Does anyone have any insight into this problem they could share?
> > An alternative would be to extend the queue to ensure apply the same
> consistent hashing mechanism to the actual queue rather than the broker.
> Does anyone know if it si possible to extend the queue implementation?
> > _______________________________________________
> > rabbitmq-discuss mailing list
> > https://lists.rabbitmq.com/cgi-bin/mailman/listinfo/rabbitmq-discuss
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