Sorry ... the callback is called with exception so I can check inside it ...
btw send() shouldn't be blocking.
Paolo PatiernoSenior Software Engineer (IoT) @ Red Hat
Microsoft MVP on Windows Embedded & IoTMicrosoft Azure Advisor
Twitter : @ppatierno
Linkedin : paolopatierno
Blog : DevExperience
> From: ppatie...@live.com
> To: users@kafka.apache.org
> Subject: RE: KafkaProducer block on send
> Date: Wed, 4 May 2016 07:24:25 +0000
>
> Hi Oleg,
>
> can you share the JIRA link here because I totally agree with you.
> For me the send() should be totally asynchronous and not blocking for the
> max.block.ms timeout.
>
> Currently I'm using the overload with callback that, of course, isn't called
> if the send() fails due to timeout.
> In order to catch this scenario I need to do the following :
>
> Future<RecordMetadata> future = this.producer.send(....);
>
> if (future.isDone()) {
> try {
> future.get();
> } catch (InterruptedException e) {
> // TODO Auto-generated catch block
> e.printStackTrace();
> } catch (ExecutionException e) {
> // TODO Auto-generated catch block
> e.printStackTrace();
> }
> }
>
> I don't like it so much ...
>
> Thanks,
> Paolo.
>
> Paolo PatiernoSenior Software Engineer (IoT) @ Red Hat
> Microsoft MVP on Windows Embedded & IoTMicrosoft Azure Advisor
> Twitter : @ppatierno
> Linkedin : paolopatierno
> Blog : DevExperience
>
> > Subject: Re: KafkaProducer block on send
> > From: ozhurakou...@hortonworks.com
> > To: users@kafka.apache.org
> > Date: Mon, 11 Apr 2016 19:42:17 +0000
> >
> > Dana
> >
> > Thanks for the explanation, but it sounds more like a workaround since
> > everything you describe could be encapsulated within the Future itself.
> > After all it "represents the result of an asynchronous computation"
> >
> > executor.submit(new Callable<RecordMetadata>() {
> > @Override
> > public RecordMetadata call() throws Exception {
> > // first make sure the metadata for the topic is available
> > long waitedOnMetadataMs = waitOnMetadata(record.topic(),
> > this.maxBlockTimeMs);
> > . . .
> > }
> > });
> >
> >
> > The above would eliminate the confusion and keep user in control where even
> > a legitimate blockage could be interrupted/canceled etc., based on various
> > business/infrastructure requirements.
> > Anyway, I’ll raise the issue in JIRA and reference this thread
> >
> > Cheers
> > Oleg
> >
> > On Apr 8, 2016, at 10:31 AM, Dana Powers
> > <dana.pow...@gmail.com<mailto:dana.pow...@gmail.com>> wrote:
> >
> > The prior discussion explained:
> >
> > (1) The code you point to blocks for a maximum of max.block.ms, which is
> > user configurable. It does not block indefinitely with no user control as
> > you suggest. You are free to configure this to 0 if you like at it will not
> > block at all. Have you tried this like I suggested before?
> >
> > (2) Even if you convinced people to remove waitOnMetadata, the send method
> > *still* blocks on memory back pressure (also configured by max.block.ms).
> > This is for good reason:
> >
> > while True:
> > producer.send(msg)
> >
> > Can quickly devour all of you local memory and crash your process if the
> > outflow rate decreases, say if brokers go down or network partition occurs.
> >
> > -Dana
> > I totally agree with Oleg.
> >
> > As documentation says the producers send data in an asynchronous way and it
> > is enforced by the send method signature with a Future returned.
> > It can't block indefinitely without returning to the caller.
> > I'm mean, you can decide that the code inside the send method blocks
> > indefinitely but in an "asynchronous way", it should first return a Future
> > to the caller that can handle it.
> >
> > Paolo.
> >
> > Paolo PatiernoSenior Software Engineer (IoT) @ Red Hat
> > Microsoft MVP on Windows Embedded & IoTMicrosoft Azure Advisor
> > Twitter : @ppatierno
> > Linkedin : paolopatierno
> > Blog : DevExperience
> >
> > Subject: KafkaProducer block on send
> > From: ozhurakou...@hortonworks.com<mailto:ozhurakou...@hortonworks.com>
> > To: users@kafka.apache.org<mailto:users@kafka.apache.org>
> > Date: Thu, 7 Apr 2016 13:04:49 +0000
> >
> > I know it’s been discussed before, but that conversation never really
> > concluded with any reasonable explanation, so I am bringing it up again as
> > I believe this is a bug that would need to be fixed in some future release.
> > Can someone please explain the rational for the following code in
> > KafkaProducer:
> >
> > @Override
> > public Future<RecordMetadata> send(ProducerRecord<K, V> record, Callback
> > callback) {
> > try {
> > // first make sure the metadata for the topic is available
> > long waitedOnMetadataMs = waitOnMetadata(record.topic(),
> > this.maxBlockTimeMs);
> > . . .
> > }
> >
> > By definition the method that returns Future implies that caller decides
> > how long to wait for the completion via Future.get(TIMETOWAIT). In this
> > case there is an explicit blocking call (waitOnMetadata), that can hang
> > infinitely (regardless of the reasons) which essentially results in user’s
> > code deadlock since the Future may never be returned in the first place.
> >
> > Thoughts?
> >
> > Oleg
> >
> >
>
