Hi Lucas, thanks for the KIP! I've got 2 questions about the assignment epoch.
dl01: To confirm I guess it should be a typo "reject all offset commit requests from a member that... includes any member epoch that is smaller or *equal to* the assignment epoch"? dl02: Should we add some discussion on assignment epochs during group protocol conversion? In the upgrade scenario, I think we can just set it to be the generation id as the classic protocol don't have such "fake zombie" issue; In the downgrade scenario, classic groups only check generation id in offset commit validation, so no need to keep the assignment epoch; In the mixed group scenario, there shouldn't be any difference because the classic members just don't have in flight commit during rebalance. Thanks, Dongnuo On Thu, Dec 18, 2025 at 3:00 PM Lucas Brutschy via dev <[email protected]> wrote: > Hi all, > > I posted a new KIP to add assignment epochs to KIP-848-style consumer > groups. The idea is to avoid failing offset commits in the new > consumer protocol by relaxing the member epoch validation slightly. > > Please take a look and let me know what you think: > > > https://cwiki.apache.org/confluence/display/KAFKA/KIP-1251%3A+Assignment+epochs+for+consumer+groups > > Cheers, > Lucas > -- [image: Confluent] <https://www.confluent.io> Dongnuo Lyu Software Engineer +1 (919) 717-3048 <+1+(919)+717-3048> Follow us: [image: Blog] <https://www.confluent.io/blog?utm_source=footer&utm_medium=email&utm_campaign=ch.email-signature_type.community_content.blog>[image: Twitter] <https://twitter.com/ConfluentInc>[image: LinkedIn] <https://www.linkedin.com/company/confluent/>[image: Slack] <https://slackpass.io/confluentcommunity>[image: YouTube] <https://youtube.com/confluent> [image: Try Confluent Cloud for Free] <https://www.confluent.io/get-started?utm_campaign=tm.fm-apac_cd.inbound&utm_source=gmail&utm_medium=organic>
