[zeromq-dev] Dropped messages when not sleeping, using 0MQ 2.1.x

Wolfgang Richter wolf at cs.cmu.edu
Sun Sep 18 18:07:06 CEST 2011

Also, perhaps you need to use zmq_term as stated:


Just another idea.


On Sun, Sep 18, 2011 at 12:05 PM, Wolfgang Richter <wolf at cs.cmu.edu> wrote:

> You aren't using threads are you?  You mentioned it was a large system.
> Make sure you don't pass sockets around between threads.
> --
> Wolf
> On Sun, Sep 18, 2011 at 11:52 AM, James Cipar <jcipar at cmu.edu> wrote:
>> Hi,
>>    I'm using PUSH/PULL sockets in a system where I have many pushers
>> connected to a single puller.  The pushers connect, send a few hundred
>> messages, then send a special "end" message and close the socket.  The
>> puller counts how many "end" messages it has received, and once it has
>> enough, it quits.
>> I'm having a problem where the "end" messages are occasionally dropped
>> (and perhaps other messages as well).  However, if I put a "sleep(1)"
>> immediately before the "close()" call, it works as expected, and all
>> messages arrive.  I am using 0MQ 2.1.9 (and also tried on 2.1.7) on Debian
>> Squeeze..  I thought that the sleep before close was no longer necessary on
>> 2.1.x.  It also seems dependent on the data set that the pushers are
>> sending.  Sometimes it works without the sleep, and sometimes it does not.
>>  Strangely, it is the *smaller* data set that causes problems.  I'd like to
>> avoid the sleep call, because I want the pushers to go on to other work as
>> soon as they finish sending data.
>> Unfortunately, I'm having trouble constructing a minimal test case.  As
>> it's a large system, and the occurrence of the error seems dependent on the
>> data being sent.  Here is the relevant code for the error:
>>    int linger;
>>    size_t l_size = sizeof(linger);
>>    sender.getsockopt(ZMQ_LINGER, (void *)(&linger), &l_size);
>>    assert(l_size == sizeof(linger));
>>    cout <<"closing sender, messages will linger for "<<linger<<"
>> milliseconds\n";
>>    sleep(1);
>>    sender.close();
>> If that "sleep" call is commented out, it will drop messages; with the
>> sleep, it will not.  The "cout" is printing -1, as expected.
>> Is there any reason to expect this system to be dropping messages?
>> _______________________________________________
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>> zeromq-dev at lists.zeromq.org
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