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Boyang Chen commented on KAFKA-7641: ------------------------------------ [~enether] Thanks! I think we need to propose two KIPs here: 1. require member id during new member join group request 2. enforce group.max.size. I could take this one as a practice for going through the consumer protocol change, do you want to work on 2. here? > Add `consumer.group.max.size` to cap consumer metadata size on broker > --------------------------------------------------------------------- > > Key: KAFKA-7641 > URL: https://issues.apache.org/jira/browse/KAFKA-7641 > Project: Kafka > Issue Type: Improvement > Reporter: Boyang Chen > Assignee: Boyang Chen > Priority: Major > > In the JIRA discussion https://issues.apache.org/jira/browse/KAFKA-7610, > Jason concluded an edge case of current consumer protocol which could cause > memory burst on broker side: > ```the case we observed in practice was caused by a consumer that was slow to > rejoin the group after a rebalance had begun. At the same time, there were > new members that were trying to join the group for the first time. The > request timeout was significantly lower than the rebalance timeout, so the > JoinGroup of the new members kept timing out. The timeout caused a retry and > the group size eventually become quite large because we could not detect the > fact that the new members were no longer there.``` > Since many disorganized join group requests are spamming the group metadata, > we should define a cap on broker side to avoid one consumer group from > growing too large. So far I feel it's appropriate to introduce this as a > server config since most times this value is only dealing with error > scenarios, client users shouldn't worry about this config. > -- This message was sent by Atlassian JIRA (v7.6.3#76005)