THIS IS A TEST INSTANCE. ALL YOUR CHANGES WILL BE LOST!!!!
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We will introduce a new AlterIsr API which requires ALTER CLUSTER_ACTION permission (similar to other InterBroker APIs such as LeaderAndIsr). The request and response schema definitions are provided below:
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In this KIP, we propose to let AlterIsr requests be sent to the controller and handled asynchronously without blocking the leader. The basic idea is to always assume the most conservative current ISR when advancing the high watermark given a pending update.
ISR Shrink: we require successful acknowledgement from the controller before a follower can be taken out of the ISR and the high watermark advanced. The leader will send the AlterIsrRequest, but will keep the current ISR fixed until a successful response is received.
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