<font face="trebuchet ms,sans-serif">Following up on this issue, the problem has worsened to a great extent. Here's a bit more information about the setup.</font><div><font face="'trebuchet ms', sans-serif">Two brokers B1 and B2, running version 2.7.1 and Erlang R14B04 on Windows, about 15000 km away from each other. Both machines running the brokers are physical machines with several cores, lots of RAM, fast disks, and reported no problems in disk access, CPU or memory consumption.�</font></div>
<div><font face="'trebuchet ms', sans-serif"><br></font></div><div><font face="'trebuchet ms', sans-serif">We have two federated durable topic exchanges X1 and X2, the upstream connection to the other broker is configured with an hearbeat of a few seconds and the prefetch count is 100. X1 is bidirectionally federated with max_hops = 1 to prevent messages from going in loops (which nonetheless suffer the additional roundtrip before being discarded, a problem I reported a while ago), X2 unidirectionally federated from B1 to B2. Messages are all published on B1, all those published on X1 are persistent, while those published on X2 aren't. Messages are published on X1 with an average rate of 3 msg/sec, and on X2 with an average rate of 10 msg/sec.</font></div>
<div><font face="'trebuchet ms', sans-serif"><br></font></div><div><font face="'trebuchet ms', sans-serif">What we experienced is that messages published on X1 queue up on the outgoing queue on B1, and even worse on the outgoing queue on B2 (although we don't care about them as the would be discarded once delivered thanks to the max_hops setting). Looking at the Web UI it appears that the acknowledges for those messages come in more slowly than messages are published, but I really can't understand why this might be the case, given the very low publish rate. The visible effect is a delay of even several minutes between when a message is published on B1 and received on B2, but again, only for the low-rate messages published on X1 (perhaps even worse for the other direction if the messages were not thrown away by the federation because of the max_hops setting, as the outgoing queue on B2 has several thousands of messages versus the few hundreds of that on B1). In other words, the only difference between the two federated exchanges appears to be the bidirectionality of the first versus the unidirectionality of the second and the fact that those published on the first are persistent.</font></div>
<div><span style="font-family:'trebuchet ms',sans-serif">The logs of the two brokers contain apparently no relevant information, and the network link between the two has always appeared to be in a good state.</span><br>
</div><div><font face="'trebuchet ms', sans-serif"><br></font></div><div><font face="'trebuchet ms', sans-serif">Any help is appreciated</font></div>
<div><br><div class="gmail_quote">On Sat, Mar 17, 2012 at 05:09, Busoli, Simone <span dir="ltr"><<a href="mailto:Simone.Busoli@ferrari.com" target="_blank">Simone.Busoli@ferrari.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<p class="MsoNormal"><font face="Calibri"><span style="font-size:11.0pt">Hello, I�ve experienced an unexpected behavior with a federated exchange whereby messages would build-up on the upstream queue for no apparent reasons.<u></u><u></u></span></font></p>
<p class="MsoNormal"><font face="Calibri"><span style="font-size:11.0pt">The network link seemed ok, as well as the two machines on which the brokers are installed.<u></u><u></u></span></font></p>
<p class="MsoNormal"><font face="Calibri"><span style="font-size:11.0pt">I would like to know under which circumstances the federation plugin on the downstream would slowdown pulling messages from the upstream.<u></u><u></u></span></font></p>
<p class="MsoNormal"><font face="Calibri"><span style="font-size:11.0pt"><u></u>�<u></u></span></font></p>
<p class="MsoNormal"><font face="Calibri"><span style="font-size:11.0pt">Thanks<u></u><u></u></span></font></p>
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