[KAFKA-15954] Review minimal effort approach on consumer last heartbeat on unsubscribe

• Type: Sub-task
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Fix Version/s: 4.0.0
• Component/s: clients, consumer
• Labels: kip-848-client-support reconciliation
• Assignee: Lianet Magrans
• Reporter: Lianet Magrans
• Created: 01/Dec/23 14:47
• Updated: 2 days ago 13:47

Description

Currently the legacy and new consumer follows a minimal effort approach when sending a leave group (legacy) or last heartbeat request (new consumer). The request is sent without waiting/handling any response. This behaviour applies when the consumer is being closed or when it unsubscribes.

For the case when the consumer is being closed, (which is a "terminal" state), it probably makes sense to just follow a minimal effort approach for "properly" leaving the group (no retry logic). But for the case of unsubscribe, we could consider if valuable to to put a little more effort into making sure that the last heartbeat is sent and received by the broker (ex. what if coordinator not known/available when sending the last HB). Note that unsubscribe could a temporary state, where the consumer might want to re-join the group at any time. 

Issue Links

• is duplicated by: KAFKA-15846 Review consumer leave group request best effort and response handling
• is related to: KAFKA-16984 New consumer should not complete leave operation until it gets a response