Also check out: http://zguide.zeromq.org/page:all#A-Shared-Key-Value-Cache-Clone-Pattern
-Michel On Mon, Jul 30, 2012 at 12:19 PM, Chuck Remes <[email protected]> wrote: > On Jul 30, 2012, at 2:05 PM, diffuser78 wrote: > >> Hi, >> >> From ZMQ guide I see that pub-sub pattern does not offer reliability, i.e. >> publisher doesn't know if the subscriber has been consuming messages. >> >> What other pattern would you recommend in pub-sub scenario where a publisher >> must know the details of subscribers and how many messages subscribers have >> consumed ? > > I should write a wiki article about an idea/opinion that I have. I brought it > up at the Chicago meetup from a few months ago. > > The only socket types that we should encourage people to use are > DEALER/ROUTER (and there was some discussion that this could be reduced to > just ROUTER sockets). With DEALER/ROUTER, it is (hopefully) obvious how to do > reliable communications between any number of peers. The patterns in the > guide illustrate this nicely and in most (all?) cases use the DEALER/ROUTER > socket types. > > For pub/sub, if you need reliability then you absolutely need bidirectional > communications at your application level. The PUB/SUB sockets in the library > do not offer this, so now you are back to DEALER/ROUTER. > > You could mimic reliable pub/sub by using two sets of sockets where the > subscribers on the first set would publish the sequence numbers that have > been received (or a range). Much like a sliding-window protocol, you could > cheaply "ack" lots of messages. But now you need to build in additional > intelligence to all subscribers so that they know to ignore duplicate > sequence numbers. Plus, you have the complexity of creating a truly unique > sequence number in a distributed system; that generator is oftentimes a > bottle neck. > > Good luck. Let us know what you figure out. > > cr > > > _______________________________________________ > zeromq-dev mailing list > [email protected] > http://lists.zeromq.org/mailman/listinfo/zeromq-dev _______________________________________________ zeromq-dev mailing list [email protected] http://lists.zeromq.org/mailman/listinfo/zeromq-dev
