I was also wondering that if commitSync acts as heartbeat then why do we still trigger heartbeat request on commit? why not just reset its time on successful commitSync? or am i wrong and we do this already?
Regards, Vinay On Thu, Apr 28, 2016 at 3:38 PM, vinay sharma <vinsharma.t...@gmail.com> wrote: > Hi Jason, > > Attached is a simple class with a main method. I used this for reproducing > issue and generate logs that i attached earlier. This class has code > snippets of poller relevant to the issue. > > Regards, > Vinay Sharma > > On Thu, Apr 28, 2016 at 3:30 PM, Jason Gustafson <ja...@confluent.io> > wrote: > >> Hey Vinay, >> >> Thanks, that's really helpful. It does seem like there might be a problem >> with the heartbeat trigger logic. I'll see if I can reproduce what you're >> seeing locally. Might be helpful if you share a snippet of your poll loop. >> >> Thanks, >> Jason >> >> On Thu, Apr 28, 2016 at 11:55 AM, vinay sharma <vinsharma.t...@gmail.com> >> wrote: >> >> > Hi Jason, >> > >> > i reverted back to KAFKA-3149. Producer still had issues related to >> schema >> > but my consumer worked. >> > >> > Now consumer worked as expected. Although i did not encountered an error >> > and generation was not marked dead by coordinator but i still see that >> > successful heartbeat response are not logged as expected. >> > My observation is following:- >> > 1) Meta refresh also triggers heartbeat request. I say this because >> > sometimes i see 2 heartbeat responses logged just a few milliseconds >> away >> > where meta refresh and proactive commit happened almost simultaneously. >> > 2) I still see that some commitSync requests do not have a heartbeat >> > logged before or after commit. Although next proactive commit happened >> just >> > in time and this time heartbeat request was successful hence saved >> session. >> > In attached log you can see that poll was done at 14:17:41, a commit >> > happened at 14:17:56 and another commit happened at 14:18:14. The only >> > heart beat response logged during this time is at 14:18:14 which is 29 >> > seconds after poll where as a commit was performed 15 seconds after >> poll. >> > Heartbeat interval was 3000. >> > 3) There are long pauses in heartbeat responses in logs which should >> cause >> > session to timeout but its not happening. This implies that commits >> trigger >> > a heartbeat but they also act as heartbeat. >> > >> > >> > Regards, >> > Vinay >> > >> > >> > On Thu, Apr 28, 2016 at 12:29 PM, Jason Gustafson <ja...@confluent.io> >> > wrote: >> > >> >> Ah, yeah. That's probably caused by the new topic metadata version, >> which >> >> isn't supported on 0.9 brokers. To test on trunk, you'd have to upgrade >> >> the >> >> brokers as well. Either that or you can rewind to before KAFKA-3306 >> (which >> >> was just committed the day before yesterday)? >> >> >> >> -Jason >> >> >> >> On Thu, Apr 28, 2016 at 9:01 AM, vinay sharma < >> vinsharma.t...@gmail.com> >> >> wrote: >> >> >> >> > Hi Jason, >> >> > >> >> > I build kafka-client and tried using it but my producers and >> consumers >> >> > started throwing below exception. Is 0.10 not going to be compatible >> >> with >> >> > brokers on version 0.9.0.1? or do i need to make some config changes >> to >> >> > producers / consumers to make them compatible with brokers on old >> >> version? >> >> > or do i need to upgrade brokers to new version as well? >> >> > >> >> > org.apache.kafka.common.protocol.types.SchemaException: Error >> reading >> >> > field 'brokers': Error reading field 'host': Error reading string of >> >> length >> >> > 17995, only 145 bytes available >> >> > at org.apache.kafka.common.protocol.types.Schema.read(Schema.java:75) >> >> > at >> >> > >> >> > >> >> >> org.apache.kafka.clients.NetworkClient.parseResponse(NetworkClient.java:380) >> >> > at >> >> > >> >> > >> >> >> org.apache.kafka.clients.NetworkClient.handleCompletedReceives(NetworkClient.java:449) >> >> > >> >> > Regards, >> >> > Vinay Sharma >> >> > >> >> > On Thu, Apr 28, 2016 at 12:32 AM, Jason Gustafson < >> ja...@confluent.io> >> >> > wrote: >> >> > >> >> > > Hey Vinay, >> >> > > >> >> > > Any chance you can run the same test against trunk? I'm guessing >> this >> >> > might >> >> > > be caused by a bug in the 0.9 consumer which basically causes some >> >> > requests >> >> > > to fail when a bunch of them are sent to the broker at the same >> time. >> >> > > >> >> > > -Jason >> >> > > >> >> > > On Wed, Apr 27, 2016 at 1:02 PM, vinay sharma < >> >> vinsharma.t...@gmail.com> >> >> > > wrote: >> >> > > >> >> > > > Hi Jason, >> >> > > > >> >> > > > This makes sense.We use 0.9.0.1 and we do have session timeout >> set a >> >> > bit >> >> > > > high but nothing can guarantee that there will be no case when >> >> > processing >> >> > > > may not go higher than session timeout. I am trying to test a >> >> proactive >> >> > > > commit approach to handle such cases when processing takes >> unusually >> >> > long >> >> > > > time. To keep consumer's session alive during long processing >> time i >> >> > > > proactively commitSync processed records every 15 seconds. >> Session >> >> > > timeout >> >> > > > i kept is 30000. >> >> > > > >> >> > > > *Problem:-* >> >> > > > With heart beat interval is 3000 then i expect a hearbeat request >> >> to be >> >> > > > sent on each proactive commit which happens every 15 seconds. In >> my >> >> > > tests i >> >> > > > see that this does not happen always. I see a time window which >> is >> >> > > greater >> >> > > > than 30 seconds where no hearbeat is sent even thought there were >> >> > commits >> >> > > > in this duration. After this window i see a couple of successful >> >> > > heartbeat >> >> > > > responses till the end of poll but as soon as i poll again and >> call >> >> > > > commitSync in next poll i get "ILLEGAL_GENERATION" error. This >> error >> >> > > always >> >> > > > happen just after meta refresh or in next poll processing after a >> >> meta >> >> > > > refresh. I am attaching logs where i kept meta refresh interval >> >> 40000, >> >> > > > 90000, 500000. >> >> > > > >> >> > > > *Test results *:- >> >> > > > Test with meta refresh 40000 ms ran around 70 seconds from 1st >> poll. >> >> > > > Test with meta refresh 90000 ms ran around 120 seconds from 1st >> >> poll. >> >> > > > Test with meta refresh 500000 ms ran around 564 seconds from 1st >> >> poll. >> >> > > > >> >> > > > Every test falls in line with above test cases where generation >> is >> >> > marked >> >> > > > dead some time after a meta refresh. Meta refresh before 1st poll >> >> does >> >> > > not >> >> > > > create any issue but the ones after poll and during long >> processing >> >> do. >> >> > > > >> >> > > > *Environment:-* >> >> > > > My setup has 3 brokers 1 zk. Topic has 3 partitions ans has >> >> replication >> >> > > > factor 3. Messages are already published to topic. >> >> > > > >> >> > > > *Logic used in test cases :- * >> >> > > > On each poll I initialize a map with current committed offset >> >> position >> >> > of >> >> > > > partitions being consumed. I update this map after each record >> >> > processing >> >> > > > and use this map to proactively commit every 15 seconds. Map is >> >> > > initialized >> >> > > > again after a proactive commit. >> >> > > > >> >> > > > I am not sure what is wrong here but i do not see any issue in >> code >> >> or >> >> > > > offset commits going on. Log files and a class with main method >> are >> >> > > > attached for your reference. >> >> > > > >> >> > > > Regards, >> >> > > > Vinay Sharma >> >> > > > >> >> > > > >> >> > > > >> >> > > > On Wed, Apr 27, 2016 at 2:46 PM, Jason Gustafson < >> >> ja...@confluent.io> >> >> > > > wrote: >> >> > > > >> >> > > >> Hi Vinay, >> >> > > >> >> >> > > >> Answers below: >> >> > > >> >> >> > > >> 1) Is it correct to say that each commitSync will trigger a >> >> > > >> HeartBeatTask? >> >> > > >> > If there is no hear beat sent in past since specified >> heartbeat >> >> > > interval >> >> > > >> > then i should see a successful heartbeat response or failure >> >> message >> >> > > in >> >> > > >> > logs near to commitSync success log? >> >> > > >> >> >> > > >> >> >> > > >> Not quite. Heartbeats are sent periodically according to the >> >> > > >> heartbeat.interval.ms configuration. However, since the >> consumer >> >> has >> >> > no >> >> > > >> background thread, they can only be sent in API calls such as >> >> poll() >> >> > or >> >> > > >> commitSync(). So calling commitSync() may or may not result in a >> >> > > heartbeat >> >> > > >> depending only on whether one is "due." >> >> > > >> >> >> > > >> 2) is it correct to say that Meta Data refresh will not act as >> >> > > heartbeat, >> >> > > >> > will not trigger heartBeatTask and will not reset >> heartBeatTask? >> >> > > >> >> >> > > >> >> >> > > >> That is correct. Metadata refreshes are not related to >> heartbeats. >> >> > > >> >> >> > > >> 3) Where does a consumer session maintained? Lets say my >> consumer >> >> is >> >> > > >> > listening to 3 partitions on a 3 broker cluster where each >> >> broker is >> >> > > >> leader >> >> > > >> > of 1 partition. So will each of the brokers will have a >> session >> >> for >> >> > my >> >> > > >> > consumer or is it just 1 session maintained somewhere in >> common >> >> like >> >> > > >> > zookeeper? >> >> > > >> >> >> > > >> >> >> > > >> One of the brokers serves as the "group coordinator." When the >> >> > consumer >> >> > > >> starts up, it sends a GroupCoordinator request to one of the >> >> brokers >> >> > to >> >> > > >> find out who the coordinator is. Currently, coordinators are >> chosen >> >> > from >> >> > > >> among the leaders of the partitions of the __consumer_offsets >> >> topic. >> >> > > This >> >> > > >> lets us take advantage of the leader election process to also >> >> handle >> >> > > >> coordinator failures. The coordinator of each group maintains >> state >> >> > for >> >> > > >> the >> >> > > >> group and keeps track of session timeouts. >> >> > > >> >> >> > > >> 4) In above setup, during a long processing if I commit a record >> >> > through >> >> > > >> > commmitSync which triggers a hear beat request and a >> successful >> >> > > >> response is >> >> > > >> > received for the same then what does this response means? >> does it >> >> > mean >> >> > > >> that >> >> > > >> > my session with each broker is renewed? or does it mean that >> just >> >> > the >> >> > > >> > leader for partition of committed record knows that my >> consumer >> >> is >> >> > > alive >> >> > > >> > and consumer's session on other brokers will still timeout? >> >> > > >> >> >> > > >> >> >> > > >> The coordinator is the only broker that is aware of a consumer's >> >> > session >> >> > > >> and all offset commits are sent to it. Successful heartbeats >> mean >> >> that >> >> > > the >> >> > > >> session is still active. Heartbeats are also used to let the >> >> consumer >> >> > > >> discover when a rebalance has begun. If a new member joins the >> >> group, >> >> > > then >> >> > > >> the coordinator returns an error code in the heartbeat >> responses of >> >> > the >> >> > > >> active members to let them know that they need to rejoin the >> group >> >> so >> >> > > that >> >> > > >> partitions can be rebalanced. >> >> > > >> >> >> > > >> I wouldn't get too hung up on commit/heartbeat behavior. The >> crux >> >> of >> >> > the >> >> > > >> issue is that you need to call poll() often enough to avoid >> getting >> >> > > timed >> >> > > >> out by the coordinator. If you find this happening frequently, >> you >> >> > > >> probably >> >> > > >> need to increase session.timeout.ms. There's not really any >> >> downside >> >> > to >> >> > > >> doing so other than that hard failures (in which the consumer >> >> can't be >> >> > > >> shutdown cleanly) will take a little longer to detect. Normal >> >> shutdown >> >> > > >> doesn't have this problem. It can be difficult in 0.9 to ensure >> >> that >> >> > > >> poll() >> >> > > >> is called often enough since you don't have direct control over >> the >> >> > > amount >> >> > > >> of data returned in poll(), but we're adding an option >> >> > > (max.poll.records) >> >> > > >> in 0.10 which hopefully can be set conservatively enough to make >> >> this >> >> > > >> problem go away. >> >> > > >> >> >> > > >> -Jason >> >> > > >> >> >> > > >> On Wed, Apr 27, 2016 at 7:11 AM, vinay sharma < >> >> > vinsharma.t...@gmail.com >> >> > > > >> >> > > >> wrote: >> >> > > >> >> >> > > >> > Hey, >> >> > > >> > >> >> > > >> > I am working on a simplified test case to check if there is >> any >> >> > issue >> >> > > >> in my >> >> > > >> > code. Just to make sure that any of my assumptions are not >> >> wrong, it >> >> > > >> will >> >> > > >> > be great if you can please help me in finding answers to >> >> following >> >> > > >> > queries:- >> >> > > >> > >> >> > > >> > 1) Is it correct to say that each commitSync will trigger a >> >> > > >> HeartBeatTask? >> >> > > >> > If there is no hear beat sent in past since specified >> heartbeat >> >> > > interval >> >> > > >> > then i should see a successful heartbeat response or failure >> >> message >> >> > > in >> >> > > >> > logs near to commitSync success log? >> >> > > >> > 2) is it correct to say that Meta Data refresh will not act as >> >> > > >> heartbeat, >> >> > > >> > will not trigger heartBeatTask and will not reset >> heartBeatTask? >> >> > > >> > 3) Where does a consumer session maintained? Lets say my >> >> consumer is >> >> > > >> > listening to 3 partitions on a 3 broker cluster where each >> >> broker is >> >> > > >> leader >> >> > > >> > of 1 partition. So will each of the brokers will have a >> session >> >> for >> >> > my >> >> > > >> > consumer or is it just 1 session maintained somewhere in >> common >> >> like >> >> > > >> > zookeeper? >> >> > > >> > 4) In above setup, during a long processing if I commit a >> record >> >> > > through >> >> > > >> > commmitSync which triggers a hear beat request and a >> successful >> >> > > >> response is >> >> > > >> > received for the same then what does this response means? >> does it >> >> > mean >> >> > > >> that >> >> > > >> > my session with each broker is renewed? or does it mean that >> just >> >> > the >> >> > > >> > leader for partition of committed record knows that my >> consumer >> >> is >> >> > > alive >> >> > > >> > and consumer's session on other brokers will still timeout? >> >> > > >> > >> >> > > >> > Regards, >> >> > > >> > Vinay Sharma >> >> > > >> > >> >> > > >> > On Tue, Apr 26, 2016 at 2:38 PM, Jason Gustafson < >> >> > ja...@confluent.io> >> >> > > >> > wrote: >> >> > > >> > >> >> > > >> > > Hey Vinay, >> >> > > >> > > >> >> > > >> > > Are you saying that heartbeats are not sent while a metadata >> >> > refresh >> >> > > >> is >> >> > > >> > in >> >> > > >> > > progress? Do you have any logs which show us the apparent >> >> problem? >> >> > > >> > > >> >> > > >> > > Thanks, >> >> > > >> > > Jason >> >> > > >> > > >> >> > > >> > > On Tue, Apr 26, 2016 at 8:18 AM, vinay sharma < >> >> > > >> vinsharma.t...@gmail.com> >> >> > > >> > > wrote: >> >> > > >> > > >> >> > > >> > > > Hi Ismael, >> >> > > >> > > > >> >> > > >> > > > Treating commitSync as heartbeat will definitely resolve >> the >> >> > issue >> >> > > >> i am >> >> > > >> > > > facing but the reason behind my issue does not seem to be >> >> what >> >> > > >> > mentioned >> >> > > >> > > in >> >> > > >> > > > defect (i.e frequent commitSync requests). >> >> > > >> > > > >> >> > > >> > > > I am sending CommitSync periodically only to keep my >> session >> >> > alive >> >> > > >> when >> >> > > >> > > my >> >> > > >> > > > consumer is still processing records and is close to >> session >> >> > time >> >> > > >> out >> >> > > >> > > > (tried 10th / 12th / 15th / 20th second after poll called >> >> where >> >> > > >> session >> >> > > >> > > > time is 30). I see heartbeat response received in logs >> along >> >> > with >> >> > > >> each >> >> > > >> > > > commitSync call but this stops after a meta data refresh >> >> request >> >> > > is >> >> > > >> > > issued. >> >> > > >> > > > I see in logs that commit goes successful but no heartbeat >> >> > > response >> >> > > >> > > > received message in logs after meta refresh till next >> poll. >> >> > > >> > > > >> >> > > >> > > > Regards, >> >> > > >> > > > Vinay Sharma >> >> > > >> > > > >> >> > > >> > > > On Mon, Apr 25, 2016 at 5:06 PM, Ismael Juma < >> >> ism...@juma.me.uk >> >> > > >> >> > > >> > wrote: >> >> > > >> > > > >> >> > > >> > > > > Hi Vinay, >> >> > > >> > > > > >> >> > > >> > > > > This was fixed via >> >> > > >> https://issues.apache.org/jira/browse/KAFKA-3470 >> >> > > >> > > > (will >> >> > > >> > > > > be part of 0.10.0.0). >> >> > > >> > > > > >> >> > > >> > > > > Ismael >> >> > > >> > > > > >> >> > > >> > > > > >> >> > > >> > > > > >> >> > > >> > > > > On Mon, Apr 25, 2016 at 1:52 PM, vinay sharma < >> >> > > >> > > vinsharma.t...@gmail.com> >> >> > > >> > > > > wrote: >> >> > > >> > > > > >> >> > > >> > > > > > Hello, >> >> > > >> > > > > > >> >> > > >> > > > > > I am using client API 0.9.0.1 and facing an issue. As >> >> per my >> >> > > >> logs >> >> > > >> > it >> >> > > >> > > > > seems >> >> > > >> > > > > > that on each commitSync(Offsets) a heartbeat request >> is >> >> sent >> >> > > but >> >> > > >> > > after >> >> > > >> > > > a >> >> > > >> > > > > > metada refresh request till next poll(), commits do >> not >> >> send >> >> > > any >> >> > > >> > > > hearbeat >> >> > > >> > > > > > request. >> >> > > >> > > > > > >> >> > > >> > > > > > KafkaConsumers i create sometimes get session time out >> >> due >> >> > to >> >> > > no >> >> > > >> > > > hearbeat >> >> > > >> > > > > > specially during longer processing times. I call >> >> > > >> > CommitSync(offsets) >> >> > > >> > > > > after >> >> > > >> > > > > > regular intervals to keep session alive when >> processing >> >> > takes >> >> > > >> > longer >> >> > > >> > > > than >> >> > > >> > > > > > usual. Every thing works fine if commit intervals are >> >> very >> >> > > >> small or >> >> > > >> > > if >> >> > > >> > > > i >> >> > > >> > > > > > commit after each record but if i commit lets say >> every >> >> 12 >> >> > > >> seconds >> >> > > >> > > and >> >> > > >> > > > 30 >> >> > > >> > > > > > seconds is session time then i can see consumer >> getting >> >> > timed >> >> > > >> out >> >> > > >> > > > > > sometimes. >> >> > > >> > > > > > >> >> > > >> > > > > > Any help or pointers will be much appreciated. Thanks >> in >> >> > > >> advance. >> >> > > >> > > > > > >> >> > > >> > > > > > Regards, >> >> > > >> > > > > > Vinay sharma >> >> > > >> > > > > > >> >> > > >> > > > > >> >> > > >> > > > >> >> > > >> > > >> >> > > >> > >> >> > > >> >> >> > > > >> >> > > > >> >> > > >> >> > >> >> >> > >> > >> > >
