Status

Current state: "Under DiscussionAccepted"

Discussion thread: here

JIRA: here

Please keep the discussion on the mailing list rather than commenting on the wiki (wiki discussions get unwieldy fast).

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We basically want to re-joining leader to know that it is the current leader of the group while avoiding computing a new assignment. We propose to achieve this by adding a SkipAssignment field in the JoinGroupResponse. When the group coordinator detects that the static leader is rejoining the group, it will set SkipAssignment to true, set the correct leader id and provide subscriptions of all members (which might be different from the leader's own subscriptions) so that the leader can monitor all topics subscribed in the group. Then the leader will send an empty SyncGroup with no assignment to collect its own (and existing) assignment. The group coordinator will do so only for consumers that support the latest version of the JoinGroup API. Other consumers will continue to behave as they do today.

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