Gordon, Thank you very much for your answer. Please see my comments and further questions below:
On Mon, Feb 1, 2016 at 3:45 AM, Gordon Sim <g...@redhat.com> wrote: > On 01/31/2016 10:19 PM, jjw tectec wrote: > >> I sent out the email more than 3 days ago, but it's still not appearing >> in the mailing list. Has it been deleted from the archive? >> > > I got the mail, but not the attached image. I actually thought I had > replied as well, but it appears not... > > On Thu, Jan 28, 2016 at 1:02 PM, jjw tectec <jjw.tec...@gmail.com >> <mailto:jjw.tec...@gmail.com>> wrote: >> >> I've set up a simple 4-broker system, where between Bs (source >> broker) and Bd (destination broker) are two middle brokers set up in >> parallel, like this: >> >> Inline image 1 >> >> The script that I used to set up all the resources & routes is shown >> at the end of this message. >> I attached a publisher to Bs and attached 3 subscribers to the other >> 3 brokers. >> What I was expecting to see was all 3 brokers should see messages. >> The actual observation was: Only B1 and Bf received messages. B2 >> never received messages, even when B1 was down. >> >> route map showed that all broker connections were set up as >> expected, but why would only the first route work and not the other? >> (I have added more brokers B3 B4... into the test, always, only the >> first established route would work.) Please help. >> > > Without the picture I'm not entirely sure I'm correctly understanding your > system. However it sounds like it may be the fact that messages from a > queue are not broadcast to all subscribers; the consumers compete for the > messages and each message goes to only one of them. > Sorry the image didn't show up. My broker setup was below: Bs Queue |---------> B1->Exchange->Queue |---------------->Bd Exchange | | |------> B2->Exchange->Queue ---| Since between Bs and Bd there are two alternative routes, I was expecting messages to be duplicated in the two routes (according to the behavior described in the C++ Broker Manual). The actual behavior was: only the first established route had the messages. I followed your suggestions (by adding ack and sending large numbers of messages in a loop), but observed the same behavior: Route 1 was the only route receiving all messages. If I shut down B1, then messages are queued up in Bs's Queue until B1 is brought up again. I remember that some time ago, I did see round robin kind of behavior (B1 and B2 were getting messages alternately), with a slightly different test setup. Now I can not replicate that anymore. Your figure below suggested creating individual queues for each downstream broker. This is not what I wanted. I wanted a single queue in the upstream broker, and the desired behavior that my application need is: Messages will flow through the first established route, say B1. But whenever B1 is down, then messages would automatically switch to the second route, say B2. (we need a "one and only one route" kind of behavior). Is this something I could achieve using static queue routes alone? I've felt that I probably need to write a shovel module between Bs and B1/B2 to make the selection or any load balancing happen. If I'm heading in a wrong direction, please kindly suggest a good path. :) Thanks jjw > > For small numbers of messages the same consumer may end up getting them > all. For larger numbers there should normally be more fair balancing. You > can improve the balance a little with the --ack option to qpid-route (which > controls the acking frequency and also prefetch). > > To use queue routes with a fanout, you would need to create and bind a > queue for each downstream broker. E.g. > > > B1->Exchange > | > |-> queue1 ---------> B2->Exchange > |-> queue2 --- > | > |------> B3->Exchange > > etc > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: users-unsubscr...@qpid.apache.org > For additional commands, e-mail: users-h...@qpid.apache.org > >
