Thanks for the quick reply. Yes sorry I do mean selectors and I am only considering non durable consumers.
So to clarify, say we have 3 brokers A,B and C. Messages are being published to A and the other brokers have active consumers with different selectors. Is it the case that broker A does not know the selectors being used so will forward the message to both B and C where the selector will be dealt with? rajdavies wrote: > > > Some background - which may help. > Information about subscriptions are passed dynamically using advisory > messages. Information about the current, active subscriptions are > forwarded - to the remote broker - as are arrivals of new > subscriptions and departures of old. By default information about > Queues and durable subscribers (even if not active) are also > forwarded. More info here: > http://activemq.apache.org/networks-of-brokers.html > Bit confused by filters - there are network filters - which filter out > destinations on a network - but I think you mean selectors ? Selectors > are part of the JMS spec and can be optionally applied to a > MessageConsumer > Rest in-lined: > On 4 Jan 2010, at 20:42, user9876 wrote: > >> >> Hi could someone please explain at a relatively low level how the >> Network of >> Brokers works. I currently have quite a simple understanding that >> once a >> network is set up, a client can publish to any broker in the network >> and >> that message will be forwarded to any subscriptions present on any >> other >> broker. I also believe these subscriptions can have filters. >> I know this is quite a broad question so the particular questions I >> have >> are: >> >> When a client subscribes to a topic on one broker, how are the other >> brokers >> in the network made aware of this new subscription and how do they >> store the >> subscriptions and the individual filters (predicates)? > Subscriptions are dynamic - so information is cached in memory. > However on re-start of a broker - it will query its message store for > queues and durable subscribers - creating a proxy active subscriber > for each. > Filters are defined in the local configuration of the broker. > Selectors on subscriptions are generally ignored. >> >> Does each broker in the network hold replicated information of the >> subscriptions present on the network? > Yes it does. >> >> If two subscriptions exist on one broker with different filters, >> will a >> message be sent once only across the network? And generally how are >> the >> messages routed? > The message will be sent once - and the selector applied locally >> >> >> >> -- >> View this message in context: >> http://old.nabble.com/network-of-brokers-internals-tp27019011p27019011.html >> Sent from the ActiveMQ - Dev mailing list archive at Nabble.com. >> > > cheers, > > Rob > > Rob Davies > http://twitter.com/rajdavies > I work here: http://fusesource.com > My Blog: http://rajdavies.blogspot.com/ > I'm writing this: http://www.manning.com/snyder/ > > > > > > > -- View this message in context: http://old.nabble.com/network-of-brokers-internals-tp27019011p27026333.html Sent from the ActiveMQ - Dev mailing list archive at Nabble.com.
