[zeromq-dev] XREQ+XREP losing messages when HWM is hit

[Martin Sustrik]

Martin,

> After some out of band discussion with Martin Hurton and Martin Sustrik, it
> turns out that this is a bug, which was introduced by commit
> 84e0c7991a9b316ed571533abc628cc1175750a3 on 2 May 2010.
> 
> The intended behaviour of XREQ is that it should not drop messages, and
> should block on ZMQ_HWM being hit just as REQ sockets do.
> 
> I will revert the problematic change on master; as a side effect devices
> such as the queue device will not function correctly when ZMQ_HWM is
> involved since the current implementation is naive and assumes that
> zmq_send() will not block.
> 
> The fix is to reimplement the queue algorithm to use zmq_poll(). I will get
> around to this eventually, in the mean time it is left as an excersize for
> the reader :-)

Thanks for this!

Martin