I think the actual evidence (I've seen two very expensive debug stories caused by this same behavior in the last few weeks) shows that returning an error in such a case is meaningless, and that a library asserting when passed bad arguments is measurably more robust, not less robust. I'm 100% sure of this. It's how CZMQ has worked since the start, including in the socket option classes, and no-one has ever flagged that as problematic. The only plausible use case is for tests, which is circular.
However, changing existing behavior isn't allowed by our C4 development contract, so I was thinking of making this optional via a build-time option in libzmq. -Pieter On Tue, Jun 17, 2014 at 1:43 AM, Thomas Rodgers <[email protected]> wrote: > If so, debug/checked builds only please. > > > > On Mon, Jun 16, 2014 at 5:11 PM, Pieter Hintjens <[email protected]> wrote: >> >> Indeed... I've had this hit more than once, a zmq_setsockopt that >> caused an error that wasn't being handled, with weird and expensive >> results down the line. >> >> Kind of makes you appreciate assertions more. CZMQ does this -- if a >> setsockopt fails for any reason except ETERM, it asserts. I might >> propose such a patch to libzmq. >> >> On Mon, Jun 16, 2014 at 8:45 PM, Gerry Steele <[email protected]> >> wrote: >> > Thanks, there was also an error in my error handling thus why it was >> > never >> > flagged. I imagine its the same in my app code. uint64_t came from the >> > cli >> > argument handling lib thus why it was used over int. A lesson learned >> > there. >> > >> > >> > >> > >> > On 16 June 2014 19:13, Pieter Hintjens <[email protected]> wrote: >> >> >> >> And indeed, this code prints "-1" as the return code: >> >> >> >> void *context = zmq_ctx_new (); >> >> void *publisher = zmq_socket (context, ZMQ_PUB); >> >> uint64_t rhwm = 0; >> >> int rc = zmq_setsockopt (publisher, ZMQ_SNDHWM, &rhwm, sizeof >> >> (rhwm)); >> >> printf ("RC=%d\n", rc); >> >> >> >> -Pieter >> >> >> >> On Mon, Jun 16, 2014 at 8:03 PM, Pieter Hintjens <[email protected]> wrote: >> >> > Hmm, it does check the size of the passed argument, and if that's >> >> > wrong, returns an error (which you do check for). >> >> > >> >> > On Mon, Jun 16, 2014 at 7:36 PM, Gerry Steele >> >> > <[email protected]> >> >> > wrote: >> >> >> Hi Pieter, you have struck on something there. >> >> >> >> >> >> Converting it to int seems to yield the correct behaviour. >> >> >> >> >> >> I guess the way setsockopt works type coercion doesn't happen. >> >> >> >> >> >> Embarrassing! But at least we got to the bottom of it. >> >> >> >> >> >> I was able to send billions of events without incurring loss. >> >> >> Apologies >> >> >> for >> >> >> taking everyones time. >> >> >> >> >> >> Thanks all. >> >> >> >> >> >> g >> >> >> >> >> >> >> >> >> >> >> >> On 16 June 2014 18:22, Pieter Hintjens <[email protected]> wrote: >> >> >>> >> >> >>> OK, just to double check, you're using ZeroMQ 4.0.x? In your test >> >> >>> case >> >> >>> (which I'm belatedly looking at), you use a uint64_t for the hwm >> >> >>> values; it should be int. Probably not significant. >> >> >>> >> >> >>> On Mon, Jun 16, 2014 at 6:20 PM, Gerry Steele >> >> >>> <[email protected]> >> >> >>> wrote: >> >> >>> > In the patent email I have links to the minimal examples on >> >> >>> > gist.github.com >> >> >>> > >> >> >>> > Happy to open an issue and commit them later on if that's what >> >> >>> > you >> >> >>> > need. >> >> >>> > >> >> >>> > Thanks >> >> >>> > >> >> >>> > On 16 Jun 2014 14:43, "Pieter Hintjens" <[email protected]> wrote: >> >> >>> >> >> >> >>> >> Gerry, can you provide a minimal test case that shows the >> >> >>> >> behavior? >> >> >>> >> Thanks. >> >> >>> >> >> >> >>> >> On Mon, Jun 16, 2014 at 12:49 PM, Gerry Steele >> >> >>> >> <[email protected]> >> >> >>> >> wrote: >> >> >>> >> > Thanks Peter. I can't try this out till I get home but it is >> >> >>> >> > looking >> >> >>> >> > like >> >> >>> >> > hwm overflows. >> >> >>> >> > >> >> >>> >> > If you run the utilities you notice the drops start happening >> >> >>> >> > after >> >> >>> >> > precisely 1000 events in the first instance (which Is the >> >> >>> >> > default >> >> >>> >> > hwm). >> >> >>> >> > >> >> >>> >> > There was another largely ignored thread about this recently >> >> >>> >> > mentioning >> >> >>> >> > the >> >> >>> >> > same problem. >> >> >>> >> > >> >> >>> >> > I also tried setting the hwm values to a number greater than >> >> >>> >> > the >> >> >>> >> > number >> >> >>> >> > of >> >> >>> >> > events and it seemed to have no effect either. >> >> >>> >> > >> >> >>> >> > g >> >> >>> >> > >> >> >>> >> > On 16 Jun 2014 09:32, "Pieter Hintjens" <[email protected]> wrote: >> >> >>> >> >> >> >> >>> >> >> On Mon, Jun 16, 2014 at 9:10 AM, Gerry Steele >> >> >>> >> >> <[email protected]> >> >> >>> >> >> wrote: >> >> >>> >> >> >> >> >>> >> >> > Big chunks of messages go missing mid flow and then pick up >> >> >>> >> >> > again. >> >> >>> >> >> > There >> >> >>> >> >> > is >> >> >>> >> >> > no literature that indicates that is expected behaviour. >> >> >>> >> >> >> >> >>> >> >> Right. The two plausible causes for this are (a) HWM >> >> >>> >> >> overflows, >> >> >>> >> >> and >> >> >>> >> >> (b) temporary network disconnects. You have excluded (a), >> >> >>> >> >> though >> >> >>> >> >> to >> >> >>> >> >> be >> >> >>> >> >> paranoid I'd probably add some temporary logging to libzmq's >> >> >>> >> >> pub >> >> >>> >> >> socket to shout out if/when it does hit the HWM. To detect >> >> >>> >> >> (b) >> >> >>> >> >> you >> >> >>> >> >> could use the socket monitoring. The third possibility is >> >> >>> >> >> that >> >> >>> >> >> you're >> >> >>> >> >> doing something wrong with subscriptions... though that seems >> >> >>> >> >> unlikely. >> >> >>> >> >> >> >> >>> >> >> -Pieter >> >> >>> >> >> _______________________________________________ >> >> >>> >> >> 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 >> >> >>> > >> >> >>> > >> >> >>> > _______________________________________________ >> >> >>> > 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 >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> -- >> >> >> Gerry Steele >> >> >> >> >> >> >> >> >> _______________________________________________ >> >> >> 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 >> > >> > >> > >> > >> > -- >> > Gerry Steele >> > >> > >> > _______________________________________________ >> > 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 > _______________________________________________ zeromq-dev mailing list [email protected] http://lists.zeromq.org/mailman/listinfo/zeromq-dev
