Sure Here are both: https://issues.apache.org/jira/browse/KAFKA-3539 https://issues.apache.org/jira/browse/KAFKA-3540
On May 4, 2016, at 3:24 AM, Paolo Patierno <ppatie...@live.com<mailto:ppatie...@live.com>> wrote: 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<mailto:ozhurakou...@hortonworks.com> To: users@kafka.apache.org<mailto: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><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><mailto:ozhurakou...@hortonworks.com> To: users@kafka.apache.org<mailto: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
