Hi, This is regards to https://issues.apache.org/jira/browse/KAFKA-9752 issue where Consumer rebalance can be stuck after new member timeout with old JoinGroup version.
We have taken the fix, but now see a different issue . Earlier the ConsumerGroup was stuck in "PendingRebalance" state , which is not happening now , but now I see members not able to join the group . I see below logs where members are being removed after session timeout. [2020-08-09 09:29:00,558] INFO [GroupCoordinator 5]: Pending member XXX in group YYY has been removed after session timeout expiration. (kafka.coordinator.group.GroupCoordinator) [2020-08-09 09:29:55,856] INFO [GroupCoordinator 5]: Pending member ZZZ in group YYY has been removed after session timeout expiration. (kafka.coordinator.group.GroupCoordinator) As I see the GroupCoridinator code, when new member tries to join for first time, GroupCoridinator also schedule addPendingMemberExpiration (in doUnknownJoinGroup call ) with *SessionTimeOut*… If for some reason , addMemberAndRebalance call takes longer (longer than SessionTimeOut), and members are still in “Pending” state, the above addPendingMemberExpiration can remove the pending member and they cannot join the group. I think that is what is happening. When for new member , Coordinator is already setting a timeout in completeAndScheduleNextExpiration(group, member, *NewMemberJoinTimeoutMs* ) What is the requirement for one more addPendingMemberExpiration task for new members ? Is this a possible bug ?
