Hi Gordon, Curious question ... would a message from an exchange configured as "Initial Value Exchange" get propagated through the topic when a new subscription is created (assuming the routing key and binding keys are a match)?
Thanks & Regards Jakub On Thu, Aug 15, 2013 at 10:44 AM, Gordon Sim <[email protected]> wrote: > On 08/14/2013 07:55 PM, Rajesh Khan wrote: > >> It seems like we are running into a requirement and I wanted to know if >> there was a way for TOPICS to preserve the last message Initially I was >> using LVQ which was really great however due to acknowledging messages and >> the delay we get because of that I moved to using QPID topics instead of >> queues. Now I want to know if there is a way of preserving the last >> message >> in a topic or if there is a way of disabling receive acknowledgment in >> Queues. >> > > The distinction between queue and topic is a slightly fuzzy one. In JMS of > course they represent two distinct messaging patterns. In pre 1.0 AMQP, > there is no concept of a 'topic' - generally the topic pattern as > understood in JMS is implemented by binding a queue per subscription to an > exchange. > > However, another way of getting a similar pattern is using a queue to > which subscribers connect as 'browsers' (non-destructive, non-competing > consumers of the messages). Used in this mode the LVQ is essentially a > topic that retains the last message for a given key value. > > For browsers on a queue, the acknowledgement isn't actually needed in that > case. > > For competing, i.e. destructive consumers, the acknowledgement can be > implied meaning no explicit acknowledgement needs to be issued. To do this > you would put 'reliability: unreliable' in your link options in the address > with which the receiver was created. > > I am however curious also as to the delay you were observing. If > acknowledging every n messages, and doing so asynchronously, I would not > expect a very large impact on throughput and certainly no 'delay' (as I > understand the term). > > > ------------------------------**------------------------------**--------- > To unsubscribe, e-mail: > [email protected].**org<[email protected]> > For additional commands, e-mail: [email protected] > >
