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https://issues.apache.org/jira/browse/KAFKA-12635?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17339143#comment-17339143
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Frank Yi commented on KAFKA-12635:
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[~yangguo1220] I was able to repro using the steps below on 2.8.0 brokers and
MM2.
# Create a topic with 1 partition on the source cluster, with `retention.ms`
set to something short like 10 seconds.
## `./kafka-topics.sh --bootstrap-server $SOURCE --create --topic myTopic
--config 'retention.ms=10000'`
# Create a consumer that consumes from the topic
## `./kafka-console-consumer.sh --bootstrap-server $SOURCE --group myConsumer
--topic myTopic`
# Send 100 messages to the topic. These should get consumed by the consumer.
Offset for this consumer on source cluster should be 100.
## `for i in $(seq 1 100); do echo $i; done | ./kafka-console-producer.sh
--bootstrap-server $SOURCE --topic myTopic`
# Wait until the retention policy deletes the records
# Start MM2 with `source->target.sync.group.offsets.enabled = true`
# Observe on the target cluster that log-end-offset is 0, offset is 100, and
lag is -100.
## `./kafka-consumer-groups.sh --bootstrap-server $TARGET --describe --group
myConsumer`
> Mirrormaker 2 offset sync is incorrect if the target partition is empty
> -----------------------------------------------------------------------
>
> Key: KAFKA-12635
> URL: https://issues.apache.org/jira/browse/KAFKA-12635
> Project: Kafka
> Issue Type: Bug
> Components: mirrormaker
> Affects Versions: 2.7.0
> Reporter: Frank Yi
> Assignee: Ning Zhang
> Priority: Major
>
> This bug occurs when using Mirrormaker with "sync.group.offsets.enabled =
> true".
> If a source partition is empty, but the source consumer group's offset for
> that partition is non-zero, then Mirrormaker sets the target consumer group's
> offset for that partition to the literal, not translated, offset of the
> source consumer group. This state can be reached if the source consumer group
> consumed some records that were now deleted (like by a retention policy), or
> if Mirrormaker replication is set to start at "latest". This bug causes the
> target consumer group's lag for that partition to be negative and breaks
> offset sync for that partition until lag is positive.
> The correct behavior when the source partition is empty would be to set the
> target offset to the translated offset, not literal offset, which in this
> case would always be 0.
> Original email thread on this issue:
> https://lists.apache.org/thread.html/r7c54ee5f57227367b911d4abffa72781772d8dd3b72d75eb65ee19f7%40%3Cusers.kafka.apache.org%3E
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