> I want to let my publisher know if he is dropping messages because he has hit > the HWM.
Then do not use pub-sub but router-dealer. Pub-sub is designed for high volumes with many subscribers. There is no useful way to deal, in the publisher, with a single slow or blocked subscriber, and ZeroMQ pub-sub does not support that. On Tue, Sep 30, 2014 at 1:36 AM, Ranganath Gunawardane <[email protected]> wrote: > Hi All, I have implemented a message router using zmq, czmq with pub-sub > pattern. > > In my simple test set up, I am using a publisher-subscriber with a proxy. I > have a fast sender and a very slow receiver causing messages to hit HWM and > drop on send. My exception is that send would fail with 'message dropped' > error, but it is not the case. the zmq_msg_send() is not giving me any error > even though the messages get dropped (I can verify this by seeing gaps in > messages in subscriber end). > > I have looked into fixing slow subscriber problem by adding a sequence > number as you suggested, specially suicidal snail pattern in the guide. But > my use case is a bit different. I really do not care about the subscribers; > I want to let my publisher know if he is dropping messages because he has > hit the HWM. > > I gather that this is the nature of pub-sub. At the same time, from > documentation, it says, if I use ZMQ_DONTWAIT, and 'if the message cannot be > queued on the socket, function call shall fail'. Does it mean that I can use > this failure as a 'send failure due to buffer full'? > > Regards. > Ranganath > > _______________________________________________ > 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
