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 > >> > > >> > > > > > > >> > > >> > > > > > >> > > >> > > > > >> > > >> > > > >> > > >> > > >> > > >> > >> > > > > >> > > > > >> > > > >> > > >> > > > > >
