Hi Guozhang, We can run a shadow setup to test the workaround hotfix if that is helpful for you. For the production cluster we'll wait for an official artifact to be released.
It is not super urgent for us because records are still being produced/consumed. The main issue is many unnecessary error and warn logs, and the unnecessary retries that follow from it. If there will be a fix for this eventually that would make us very happy :-) Thanks for your efforts so far, and let me know if I can do anything to assist. We could continue this work via Slack if you prefer. Best, Pieter -----Oorspronkelijk bericht----- Van: Guozhang Wang <wangg...@gmail.com> Verzonden: Wednesday, 12 June 2019 20:30 Aan: users@kafka.apache.org Onderwerp: Re: Repeating UNKNOWN_PRODUCER_ID errors for Kafka streams applications @Jonathan Actually after double checking the code I realized https://issues.apache.org/jira/browse/KAFKA-7190 would not completely resolve this issue, as explained in my previous email to Pieter. @Pieter Your concerns about this issue makes sense to me. Are you willing to compile from source code than from a downloaded artifact? I can try to provide you a quick workaround hotfix if you're willing to do the former. Guozhang On Wed, Jun 12, 2019 at 4:13 AM Pieter Hameete <pieter.hame...@blockbax.com> wrote: > Hey Jonathan, > > Thanks for the input. We've looked into the issue you linked but > changing the topic config didn’t work for us (see earlier mails in this > thread). > Could you elaborate a bit more on the specifics of your situation? > > How many partitions do you have for the repartition topics? What is > your commit.interval.ms setting for the streams application? What is > the frequency (volume) at which records are produced to each partition > in your case? > > I'm trying to get a better idea of what 'low rate' and 'high volume' are. > Specifically in comparison to your topic and Kafka streams app > configuration. We produce records to a partition every 5 seconds, and > this results in errors which is unexpected to us because we run a EOS > configuration with default settings and we don't regard 1 record per 5 > seconds per partition as super low volume with respect to these > default settings. > > Best, > > Pieter > > -----Oorspronkelijk bericht----- > Van: Jonathan Santilli <jonathansanti...@gmail.com> > Verzonden: Tuesday, 11 June 2019 14:14 > Aan: Kafka Users <users@kafka.apache.org> > Onderwerp: Re: Repeating UNKNOWN_PRODUCER_ID errors for Kafka streams > applications > > Hello, > > we currently see the same WARN logs when the App is processing low > rate of records, as soon the app starts processing a high volume of > records, those WARN stop showing in the logs. > According to other email threads, this should be fixed with > https://issues.apache.org/jira/browse/KAFKA-7190. > > We use version 2.2.1, with EOS > > Cheers! > -- > Jonathan > > > On Tue, Jun 11, 2019 at 11:04 AM Pieter Hameete < > pieter.hame...@blockbax.com> > wrote: > > > Hi Guozhang, > > > > Thanks that clarifies a lot. The segment size or segment ms is not > > the issue here then, changing these properties does not make the > > errors go away either 😊 > > > > Regarding the proposed solutions: > > > > 1) We use EOS, so the commit interval is defaulted to 100 ms in our case. > > We don't want to delay consumers that respect transactions in their > > consumption of the produced events so increasing this config is not > > a good option for us. We have tried temporarily increasing it to 30s > > and indeed partitions receiving records at a higher frequency (i.e. > > 1 per > > 5 seconds) stopped resulting in errors. Partitions receiving records > > at > a lower (i.e. > > 1 per minute) frequency were still resulting in errors. > > > > 2) We have a small disparity in keys, so the data is already spread > > over a small (3 or 4) number of partitions. I don't think reducing > > the number of partitions to for example 4 will make a difference in > > this > case? > > > > My attempt to summarize the issue here would be the following: > > > > If exactly once is enabled and records are produced on a partition > > less frequent than the commit interval, then the brokers/producers > > will produce an UNKNOWN_PRODUCER_ID error/warning on each produced > > record and the producers need to retry once for every produced record. > > This happens because commits trigger truncation of the producer ID > > map causing producers that did not produce any messages since last > > commit to have their ID removed. > > > > In our case we use a Kafka Streams application with exactly once > > enabled and a default commit.interval.ms of 100ms. We don't wish to > > increase this default to allow the consumers to be as real-time as > > possible. Even if we would scale down to 1 partition (which is > > undesirable) I don't think the producers would produce a record to > > this one partition between every offset commit. Basically we can't > > resolve this problem unless we would have a volume large enough to > > produce a record on each partition between every offset commit. > > > > Our only options seem to be to move from exactly once to at least > > once, or to wait for > > > https://cwiki.apache.org/confluence/display/KAFKA/KIP-360%3A+Improve+h > andling+of+unknown+producer > . > > > > > > Best, > > > > Pieter > > > > -----Oorspronkelijk bericht----- > > Van: Guozhang Wang <wangg...@gmail.com> > > Verzonden: Monday, 10 June 2019 22:19 > > Aan: users@kafka.apache.org > > Onderwerp: Re: Repeating UNKNOWN_PRODUCER_ID errors for Kafka > > streams applications > > > > Hi Pieter, > > > > My reasoning is that the most recent segment (called the `active` > > segment`) would not be deleted for immediately since it is still > > being appended. I.e. > > say you have two segments offset range at [0, 100), [100, 180). And > > if the delete records API is issued to delete any records older than > > 150, then the first segment would be deleted, but the second (and > > the active one) would not be deleted. Instead we would only set the > log-starting-offset at 150. > > > > But when I double checked the code again, I realized that even if we > > do not delete the segment, we would still "truncate" the maintained > > producer ID map, and hence what you've seen is correct: although the > > data cleaner did not delete the segment file yet, corresponding > > producer ID would still be removed. > > > > So for now what I can think of to reduce this issue, are that you > > can either consider 1) increase your commit interval, and hence > > reduce the delete-records frequency, or 2) decrease your > > num.partitions so that the per-partition traffic from a single producer can > > be reasonably large. > > > > > > Guozhang > > > > > > On Fri, Jun 7, 2019 at 2:09 AM Pieter Hameete > > <pieter.hame...@blockbax.com > > > > > wrote: > > > > > Hi Guozhang, > > > > > > I've checked the log-cleaner.log on the brokers for cleanup of > > > repartition topics for the event-rule-engine application, but I > > > found no reports of frequent cleanup there. > > > > > > Also forgive me if I am wrong, because I don’t understand the > > > exact mechanics of the log cleanup processes. But didn't > > > KAFKA-6150 ( > > > https://github.com/apache/kafka/pull/4270/) introduce a log > > > cleanup mechanic for repartition topics that cleans up the logs > > > more aggressively (i.e. not following the regular LogCleaner > > > cleanup process that is triggered by segment.ms and segment.bytes) > > > by deleting records via the admin client based on committed input > > > topic > offsets. > > > This would explain producer id's not being known if the logs get > > > cleaned up almost instantly via this process. > > > > > > Best, > > > > > > Pieter > > > > > > -----Oorspronkelijk bericht----- > > > Van: Guozhang Wang <wangg...@gmail.com> > > > Verzonden: Thursday, 6 June 2019 18:16 > > > Aan: users@kafka.apache.org > > > Onderwerp: Re: Repeating UNKNOWN_PRODUCER_ID errors for Kafka > > > streams applications > > > > > > Pieter, > > > > > > KIP-360 should be able to fix it, yes, but it won't be completed > > > soon, and the earliest release it may get in is in 2.4. At the > > > mean time, I thought that be increasing the segment size, hence > > > reducing the frequency that records being truncated and hence > > > causing producer ID to be removed to be much smaller. > > > > > > If you look at the broker-side logs, could you see if the log > > > cleanup threads logs that truncating the > > > event-rule-engine-KSTREAM-REDUCE-STATE-STORE-0000000015-repartitio > > > n- xx partitions? If it is too frequent that would cause the > > > producer ID stored on brokers to be removed too early and > > > therefore UNKNOWN_PRODUCER_ID, but overriding the segment size / > > > ms should prevent it from being triggered too often. > > > > > > Guozhang > > > > > > > > > On Thu, Jun 6, 2019 at 5:10 AM Pieter Hameete > > > <pieter.hame...@blockbax.com > > > > > > > wrote: > > > > > > > Hello, > > > > > > > > We also found this earlier email in the archives which looks > > > > very much like what we are experiencing: > > > > > > > > > > > > http://mail-archives.apache.org/mod_mbox/kafka-users/201811.mbox > > > > /% > > > > 3C > > > > CA > > > > M0VdefApmc5wBZQaJmQtbcnZ_OOgGv84qCuPoJS-KU4B=e...@mail.gmail.com > > > > %3 > > > > E > > > > > > > > So it seems like: > > > > > > > > * It only happens with EXACTLY_ONCE processing > > > > * It only happens on repartition topics (probably due to the > > > > changes in > > > > https://issues.apache.org/jira/browse/KAFKA-6150) > > > > * The errors are happening continuously (on each produced > > > > message) > > > > > > > > The email I referred to points to > > > > https://issues.apache.org/jira/browse/KAFKA-7190 for ongoing > > > > work on solving this issue. However, it seems that this 7190 > > > > solves the UNKNOWN_PRODUCER_ID with a different cause (low > > > > traffic). The hotfix of changing the retention settings on the > > > > topic does not seem to resolve the errors in our case. > > > > > > > > Do you think the changes listed under KIP-360 > > > > https://cwiki.apache.org/confluence/display/KAFKA/KIP-360%3A+Imp > > > > ro > > > > ve > > > > +h > > > > andling+of+unknown+producer > > > > could solve what we are seeing here? > > > > > > > > Best, > > > > > > > > Pieter > > > > > > > > -----Oorspronkelijk bericht----- > > > > Van: Pieter Hameete <pieter.hame...@blockbax.com> > > > > Verzonden: Thursday, 6 June 2019 13:39 > > > > Aan: users@kafka.apache.org > > > > Onderwerp: RE: Repeating UNKNOWN_PRODUCER_ID errors for Kafka > > > > streams applications > > > > > > > > Hi Guozhang, Matthias, > > > > > > > > @Guozhang The brokers are on version 2.2.0-cp2 and the clients > > > > are version 2.2.1. We have upgraded yesterday from 2.1.1 to this > > > > version to see if it would make a difference, but unfortunately > > > > not. After restarting the brokers and streams applications the > > > > broker errors and client warnings continued as before. > > > > > > > > @Matthias I've increased the segment.bytes to be 10 times the > > > > default but this does not change anything. > > > > > > > > For my understanding: why are retention settings important here? > > > > Because the producer which is logging the UNKNOWN_PRODUCER_ID > > > > exception produced a message 5 seconds earlier (with the same > > > > exception though..). I remember from one of your comments > > > > (Matthias) that the brokers build up the set of known producers > > > > from > the log. > > > > If a message was produced on a partition 5 seconds before by the > > > > same producer (confirmed via kafkacat), how can it be the broker > > > > throws an > > > UNKNOWN_PRODUCER_ID exception? > > > > > > > > Best, > > > > > > > > Pieter > > > > > > > > -----Oorspronkelijk bericht----- > > > > Van: Guozhang Wang <wangg...@gmail.com> > > > > Verzonden: Thursday, 6 June 2019 01:39 > > > > Aan: users@kafka.apache.org > > > > Onderwerp: Re: Repeating UNKNOWN_PRODUCER_ID errors for Kafka > > > > streams applications > > > > > > > > Hello Pieter, > > > > > > > > It's normal to see offset increasing by 2: that is because each > > > > message on that partition is from a separate transaction which > > > > Streams EOS leverage on, and whenever a a txn commits a commit > > > > marker, written as a special message would be appended but not > > > > exposed > > to consumers. > > > > And hence that txn marker will take one offset as well. > > > > > > > > Your overridden configs look good to me, and it's indeed weird > > > > why it did not mitigate your observed issue. Which Kafka version > > > > did you > > use? > > > > > > > > > > > > Guozhang > > > > > > > > > > > > On Wed, Jun 5, 2019 at 4:43 AM Pieter Hameete > > > > <pieter.hame...@blockbax.com > > > > > > > > > wrote: > > > > > > > > > Hi Guozhang, > > > > > > > > > > Some additional finding: it seems to only happen on Kakfa > > > > > Streams repartition topics. We haven't seen this happening for > > > > > any other topics so far. > > > > > > > > > > Best, > > > > > > > > > > Pieter > > > > > > > > > > -----Oorspronkelijk bericht----- > > > > > Van: Pieter Hameete <pieter.hame...@blockbax.com> > > > > > Verzonden: Wednesday, 5 June 2019 11:23 > > > > > Aan: users@kafka.apache.org > > > > > Onderwerp: RE: Repeating UNKNOWN_PRODUCER_ID errors for Kafka > > > > > streams applications > > > > > > > > > > Hi Guozhang, > > > > > > > > > > Thanks for your reply! I noticed my original mail went out > > > > > twice by accident, sorry for that. > > > > > > > > > > We currently have a small variety of keys so not all > > > > > partitions are 'actively used' indeed. The strange thing is > > > > > though is that the errors occur for the partitions that > > > > > actively receive records every few seconds. I have checked > > > > > this using kafkacat to consume the specific > > > > partitions. > > > > > Something I noticed was that for each received record the > > > > > partition offset was 2 higher than the previous record, > > > > > instead of the expected 1. Could that be due to the producers > > > > > retrying (see warning logs in my original mail)? > > > > > > > > > > I've done the override for the configs in the repartition > > > > > topics as follows, on one of the brokers: > > > > > > > > > > The values are taken from your KIP-443 > > > > > https://cwiki.apache.org/confluence/display/KAFKA/KIP-443%3A+R > > > > > et > > > > > ur > > > > > n+ > > > > > to > > > > > +default+segment.ms+and+segment.index.bytes+in+Streams+reparti > > > > > +default+ti > > > > > +default+on > > > > > +default++t > > > > > +default+op > > > > > ics > > > > > > > > > > kafka-topics --zookeeper localhost:2181 --alter --topic > > > > > event-rule-engine-KSTREAM-REDUCE-STATE-STORE-0000000015-repart > > > > > it io n --config segment.index.bytes=10485760 kafka-topics > > > > > --zookeeper > > > > > localhost:2181 --alter --topic > > > > > event-rule-engine-KSTREAM-REDUCE-STATE-STORE-0000000015-repart > > > > > it io n --config segment.bytes= 52428800 kafka-topics > > > > > --zookeeper > > > > > localhost:2181 --alter --topic > > > > > event-rule-engine-KSTREAM-REDUCE-STATE-STORE-0000000015-repart > > > > > it io n --config segment.ms=604800000 kafka-topics --zookeeper > > > > > localhost:2181 --alter --topic > > > > > event-rule-engine-KSTREAM-REDUCE-STATE-STORE-0000000015-repart > > > > > it > > > > > io > > > > > n > > > > > --config retention.ms=-1 > > > > > > > > > > Verifying afterwards: > > > > > > > > > > kafka-topics --zookeeper localhost:2181 --describe --topic > > > > > event-rule-engine-KSTREAM-REDUCE-STATE-STORE-0000000015-repart > > > > > it > > > > > io > > > > > n > > > > > > > > > > Topic:event-rule-engine-KSTREAM-REDUCE-STATE-STORE-0000000015- > > > > > re > > > > > pa > > > > > rt > > > > > it > > > > > ion > > > > > > > > > > PartitionCount:32 ReplicationFactor:3 > > > > > Configs:segment.bytes=52428800,retention.ms > > > > > =-1,segment.index.bytes=10485760,segment.ms > > > > > =604800000,cleanup.policy=delete > > > > > > > > > > Is there anything that seems off to you? Or something else I > > > > > can investigate further? We'd really like to nail this issue down. > > > > > Especially because the cause seems different than the 'low traffic' > > > > > cause in JIRA issue KAFKA-7190 as the partitions for which > > > > > errors are thrown are receiving data. > > > > > > > > > > Best, > > > > > > > > > > Pieter > > > > > > > > > > -----Oorspronkelijk bericht----- > > > > > Van: Guozhang Wang <wangg...@gmail.com> > > > > > Verzonden: Wednesday, 5 June 2019 02:23 > > > > > Aan: users@kafka.apache.org > > > > > Onderwerp: Re: Repeating UNKNOWN_PRODUCER_ID errors for Kafka > > > > > streams applications > > > > > > > > > > Hello Pieter, > > > > > > > > > > If you only have one record every few seconds that may be too > > > > > small given you have at least 25 partitions (as I saw you have > > > > > a > > > > > xxx--repartition-24 partition), which means that for a single > > > > > partition, it may not see any records for a long time, and in > > > > > this case you may need to override it to very large values. On > > > > > the other hand, if you can reduce your num.partitions that may > > > > > also help > > > > increasing the traffic per partition. > > > > > > > > > > Also could you show me how did you override the configs in the > > > > > repartition topics? > > > > > > > > > > > > > > > Guozhang > > > > > > > > > > On Tue, Jun 4, 2019 at 2:10 AM Pieter Hameete > > > > > <pieter.hame...@blockbax.com > > > > > > > > > > > wrote: > > > > > > > > > > > Hello, > > > > > > > > > > > > Our Kafka streams applications are showing the following > > > > > > warning every few seconds (on each of our 3 brokers, and on > > > > > > each of the > > > > > > 2 instances of the streams application): > > > > > > > > > > > > > > > > > > [Producer > > > > > > clientId=event-rule-engine-dd71ae9b-523c-425d-a7c0-c62993315 > > > > > > b3 > > > > > > 0- > > > > > > St > > > > > > re am Thread-1-1_24-producer, > > > > > > transactionalId=event-rule-engine-1_24] > > > > > > Resetting sequence number of batch with current sequence 1 > > > > > > for partition > > > > > > event-rule-engine-KSTREAM-REDUCE-STATE-STORE-0000000015-repa > > > > > > rt > > > > > > it > > > > > > io > > > > > > n- > > > > > > 24 > > > > > > to 0 > > > > > > > > > > > > > > > > > > > > > > > > Followed by: > > > > > > > > > > > > > > > > > > > > > > > > [Producer > > > > > > clientId=event-rule-engine-dd71ae9b-523c-425d-a7c0-c62993315 > > > > > > b3 > > > > > > 0- > > > > > > St > > > > > > re am Thread-1-1_24-producer, > > > > > > transactionalId=event-rule-engine-1_24] > > > > > > Got error produce response with correlation id 5902 on > > > > > > topic-partition > > > > > > event-rule-engine-KSTREAM-REDUCE-STATE-STORE-0000000015-repa > > > > > > rt > > > > > > it > > > > > > io > > > > > > n- > > > > > > 24 , retrying (2147483646 attempts left). Error: > > > > > > UNKNOWN_PRODUCER_ID > > > > > > > > > > > > The brokers are showing errors that look related: > > > > > > > > > > > > > > > > > > Error processing append operation on partition > > > > > > event-rule-engine-KSTREAM-REDUCE-STATE-STORE-0000000015-repa > > > > > > rt > > > > > > it > > > > > > io > > > > > > n- > > > > > > 24 > > > > > > (kafka.server.ReplicaManager) > > > > > > > > > > > > org.apache.kafka.common.errors.UnknownProducerIdException: > > > > > > Found no record of producerId=72 on the broker. It is > > > > > > possible that the last message with the producerId=72 has > > > > > > been removed due to hitting the > > > > > retention limit. > > > > > > > > > > > > > > > > > > > > > > > > We would expect the UNKNOWN_PRODUCER_ID error to occur once. > > > > > > After a retry the record would be published on the partition > > > > > > and the PRODUCER_ID would be known. However, this error > > > > > > keeps occurring every few seconds. This is roughly at the > > > > > > same rate at which records are produced on the input topics > > > > > > partitions, so it seems like it occurs for > > > > > (nearly) every input record. > > > > > > > > > > > > > > > > > > > > > > > > The following JIRA issue: > > > > > > https://issues.apache.org/jira/browse/KAFKA-7190 > > > > > > looks related. Except the Jira issue mentions ‘little > > > > > > traffic’, and I am not sure if a message per every few > > > > > > seconds is regarded as little > > > > > traffic. > > > > > > Matthias mentions in the issue that a workaround seems to be > > > > > > to increase topic configs `segment.bytes`, > > > > > > `segment.index.bytes`, and `segment.ms` for the > > > > > > corresponding repartition topics. We’ve tried manually > > > > > > overriding these configs for a relevant topic to the config > > > > > > values in the linked pull request > > > > > > (https://github.com/apache/kafka/pull/6511) but this did not > > > > > > result in > > > > > the errors disappearing. > > > > > > > > > > > > > > > > > > > > > > > > Could anyone help us to figure out what is happening here, > > > > > > and why the proposed fix for the above JIRA issue is not > > > > > > working in this > > > case? > > > > > > > > > > > > > > > > > > > > > > > > Best, > > > > > > > > > > > > > > > > > > > > > > > > Pieter > > > > > > > > > > > > > > > > > > > > > > -- > > > > > -- Guozhang > > > > > > > > > > > > > > > > > -- > > > > -- Guozhang > > > > > > > > > > > > > -- > > > -- Guozhang > > > > > > > > > -- > > -- Guozhang > > > > > -- > Santilli Jonathan > -- -- Guozhang
