Pieter,
here is my fix. Let me know if you see any problem. I am not sure if there is
anything to be done for the "active" pipe.
I have tried the fix in my stress test and it seemed to work so far.
Also just curious, would this affect any other types of sockets?
(I don't use git therefore no git pull patch. my change is based on source from
3.2.2.)
pipe.cpp
old version:
void zmq::dist_t::terminated (pipe_t *pipe_)
{
// Remove the pipe from the list; adjust number of matching, active and/or
// eligible pipes accordingly.
if (pipes.index (pipe_) < matching)
matching--;
if (pipes.index (pipe_) < active)
active--;
if (pipes.index (pipe_) < eligible)
eligible--;
pipes.erase (pipe_);
}
new version: (added a bool swapEligible)
void zmq::dist_t::terminated (pipe_t *pipe_)
{
// Remove the pipe from the list; adjust number of matching, active and/or
// eligible pipes accordingly.
if (pipes.index (pipe_) < matching)
matching--;
if (pipes.index (pipe_) < active)
active--;
bool swapEligible = false;
if (pipes.index (pipe_) < eligible) {
eligible--;
swapEligible = true;
}
if (swapEligible) {
pipes.swap(pipes.index(pipe_), eligible);
pipes.erase(eligible);
} else {
pipes.erase (pipe_);
}
}
----- Original Message -----
From: Pieter Hintjens
Sent: 03/21/13 10:06 AM
To: ZeroMQ development list
Subject: Re: [zeromq-dev] subscriber stopped receiving messages from XPUB socket
Hi Winston, Great analysis of the problem! Would you like to send a pull
request with a patch? -Pieter On Thu, Mar 21, 2013 at 2:43 PM, Winston Huang
<[email protected]> wrote: > Pieter, > > Thanks for your reply. I think I might
have found the problem. I have a xpub > socket that has about 10 subscribers.
The following events happened: > > 1) one subscriber's hwm is reached and it's
moved to the end of the pipes. > (in zmq::dist_t::write). > > 2) another
subscriber was terminated (zmq::xpub_t::xterminated), causing the > pipe to be
removed from the dist. however in zmq::dist_t::terminated, the > terminated
pipe was removed by moving the last pipe to the to-be-removed > pipe's spot.
therefore the deactivated pipe in step 1 is moved in the front > of the pipes.
in the meantime, the value of eligible and active are > decremented. therefore
the last eligible pipe (which was in front of the > de-activated pipe before
this event) now becomes in-eligible. and it will > not receive any messages
after this. > > let me know if this makes any sense. it's hard for me to write
a standalone > test case like this. I hope my explanation is clear. And if you
can suggest > any fix, let me know. I can see one fix is to swap with the last
eligible > pipe and then delete that position. > > Thanks, > Winston > > > >
----- Original Message ----- > > From: Pieter Hintjens > > Sent: 03/15/13 09:15
AM > > To: ZeroMQ development list > > Subject: Re: [zeromq-dev] subscriber
stopped receiving messages from XPUB > socket > > > > It sounds like a problem
in the subscription forwarding, yet it's not > clear how a subscriber could be
affected by the publisher restarting, > with the proxy in between. > > Do you
need the proxy at all? First thing would be to connect > subscribers directly
to the publisher. If the problem then still > happens we can try to make a
reproducible test case. > > -Pieter > > > > On Fri, Mar 15, 2013 at 4:59 AM,
Winston Huang <[email protected]> wrote: >> hi there, >> >> I have multiple
(5-10) subscribers subscribing to the same topic published >> by one publisher.
They are connected via a XSUB-XPUB proxy. All the >> subscribers are always up
and the publisher may come and go at times. I >> have >> noticed that at times,
after the publisher is restarted, one of the >> subscribers might stop
receiving any messages at all. It's not a >> slow-joiner >> kind of issue
because the publisher continues to publish message every >> second and that
subscriber may not get any messages at all forever, >> whereas >> other
subscribers are getting messages at the same time. I also verified >> that the
subscriber is waiting for messages (it's calling the receive >> function.) and
if I restart the subscriber, it will get messages again. >> >> Could someone
enlighten me what I may be doing wrong? Is there any thing I >> should be
looking into? >> >> Thanks in advance. >> Winston >>
_______________________________________________ >> 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 > > > > >
_______________________________________________ > zeromq-dev mailing list >
[email protected] >
http://lists.zeromq.org/mailman/listinfo/zeromq-dev >
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