[
https://issues.apache.org/jira/browse/KAFKA-19522?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Calvin Liu updated KAFKA-19522:
-------------------------------
Description:
In PartitionChangeBuilder, there is a bug that even if the laterKnownLeader is
fenced, it can still be a leader.
The effect could be minor. Here is a real case:
When all the replicas(0, 1, 2) are down, the ELR set could be (1, 2) and the
last known leader is (2). The leader is -1.
Then if 0 and 1 come up uncleanly the ELR field will be (2). This partition
can't elect 2 as the leader, because ELR is not empty.
Then when 2 comes up, it comes up cleanly, then we are happy to have it as the
new leader cleanly(through ELR election). However, if it comes up uncleanly, it
will be elected as the leader uncleanly. Though it is expected, notice that,
replica 2 is still fenced until the next heartbeat. So effectively, broker 2 is
just elected as the leader a little bit ahead of time.
was:In PartitionChangeBuilder, there is a bug that even if the
laterKnownLeader is fenced, it can still be a leader
> LastKnownLeader should only be elected if it is unfenced
> --------------------------------------------------------
>
> Key: KAFKA-19522
> URL: https://issues.apache.org/jira/browse/KAFKA-19522
> Project: Kafka
> Issue Type: Bug
> Affects Versions: 4.1.0
> Reporter: Calvin Liu
> Assignee: Calvin Liu
> Priority: Major
> Fix For: 4.1.0
>
>
> In PartitionChangeBuilder, there is a bug that even if the laterKnownLeader
> is fenced, it can still be a leader.
> The effect could be minor. Here is a real case:
> When all the replicas(0, 1, 2) are down, the ELR set could be (1, 2) and the
> last known leader is (2). The leader is -1.
> Then if 0 and 1 come up uncleanly the ELR field will be (2). This partition
> can't elect 2 as the leader, because ELR is not empty.
> Then when 2 comes up, it comes up cleanly, then we are happy to have it as
> the new leader cleanly(through ELR election). However, if it comes up
> uncleanly, it will be elected as the leader uncleanly. Though it is expected,
> notice that, replica 2 is still fenced until the next heartbeat. So
> effectively, broker 2 is just elected as the leader a little bit ahead of
> time.
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
