yes, but the consumers all have to be present, they already content for the lock.
imagine an app that has a hot standby, both the primary and hot standby have started consumers. The broker delivers messages to the first consumer, the primary (because it got there first) and when/if it fails, it will deliver messages to the second consumer (the hot standby). So the broker chooses but only from among the current active consumers. On 22 April 2010 09:09, TonyTobin <cavanaght...@hotmail.com> wrote: > > Thank you for your reply Gary, > > In the documentation for exclusive Consumer, it states > > "The broker will pick a single MessageConsumer to get all the messages for > a > queue to ensure ordering. If that consumer fails, the broker will auto > failover and choose another consumer" > > Doesnt this mean that the broker selects the next consumer, rather than the > consumer going for the lock. > > Thanks again for your reply. > > > > Gary Tully wrote: > > > > exclusive consumer is a simple solution to the case where there are many > > consumers but only one should be active at any time. Rather than some > > application logic keeping track of which one should be active, they all > > have > > a go and the broker ensures exclusive access. > > > > So each consumer connects but only one of them gets the exclusive lock > and > > gets the messages. When it dies, the next consumer in line gets the > > messages. If effectively allows consumers to stack waiting for the > current > > consumer to die. > > > > On 21 April 2010 16:35, TonyTobin <cavanaght...@hotmail.com> wrote: > > > >> > >> In the ActiveMQ doc http://activemq.apache.org/exclusive-consumer.htmlit > >> states > >> > >> The broker will pick a single MessageConsumer to get all the messages > for > >> a > >> queue to ensure ordering. If that consumer fails, the broker will auto > >> failover and choose another consumer. > >> > >> Is this a consumer master slave relationship, the broker will send all > >> messages to the designated consumer, and the consumer passes the > messages > >> onto the other consumers. Or does the broker send the messages to all > the > >> consumers, but only one consumer acknowledges them, so if that consumer > >> dies the other consumer can then pick up where the first consumer died. > >> > >> If there is a link that covers Queue consumer clusters in more depth, I > >> would be grateful if you could post it. > >> > >> Thanks Tony > >> > >> Thanks Tony > >> > >> > >> -- > >> View this message in context: > >> > http://old.nabble.com/Understanding-the-Exclusive-Consumer-tp28288049p28288049.html > >> Sent from the ActiveMQ - User mailing list archive at Nabble.com. > >> > >> > > > > > > -- > > http://blog.garytully.com > > > > Open Source Integration > > http://fusesource.com > > > > > > -- > View this message in context: > http://old.nabble.com/Understanding-the-Exclusive-Consumer-tp28288049p28325468.html > Sent from the ActiveMQ - User mailing list archive at Nabble.com. > > -- http://blog.garytully.com Open Source Integration http://fusesource.com
