[
https://issues.apache.org/jira/browse/KAFKA-3083?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15097302#comment-15097302
]
Flavio Junqueira commented on KAFKA-3083:
-----------------------------------------
It sounds like this comment from [~junrao] is extending the description of the
jira. It assumes that the replica that was removed from the ISR in step 1
eventually came back, but it coming back isn't reflected in the state of ZK.
However, the replica would be in the cache of the controller B, so would it be
elected in this case? Would it be an actual problem if the B is demoted and
another controller comes up?
> a soft failure in controller may leader a topic partition in an inconsistent
> state
> ----------------------------------------------------------------------------------
>
> Key: KAFKA-3083
> URL: https://issues.apache.org/jira/browse/KAFKA-3083
> Project: Kafka
> Issue Type: Bug
> Components: core
> Affects Versions: 0.9.0.0
> Reporter: Jun Rao
> Assignee: Mayuresh Gharat
>
> The following sequence can happen.
> 1. Broker A is the controller and is in the middle of processing a broker
> change event. As part of this process, let's say it's about to shrink the isr
> of a partition.
> 2. Then broker A's session expires and broker B takes over as the new
> controller. Broker B sends the initial leaderAndIsr request to all brokers.
> 3. Broker A continues by shrinking the isr of the partition in ZK and sends
> the new leaderAndIsr request to the broker (say C) that leads the partition.
> Broker C will reject this leaderAndIsr since the request comes from a
> controller with an older epoch. Now we could be in a situation that Broker C
> thinks the isr has all replicas, but the isr stored in ZK is different.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
