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https://issues.apache.org/jira/browse/KAFKA-5600?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Ismael Juma updated KAFKA-5600:
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Summary: Group loading regression causing stale metadata/offsets cache
(was: GroupMetadataManager doesn't read offsets of segmented logs correctly)
> Group loading regression causing stale metadata/offsets cache
> -------------------------------------------------------------
>
> Key: KAFKA-5600
> URL: https://issues.apache.org/jira/browse/KAFKA-5600
> Project: Kafka
> Issue Type: Bug
> Components: core
> Affects Versions: 0.10.2.1, 0.11.0.0
> Environment: any
> Reporter: Jan Burkhardt
> Priority: Critical
> Labels: regression, reliability
> Fix For: 0.11.0.1, 0.11.1.0
>
> Attachments: KafkaErrorConsumer.java, KafkaErrorProducer.java
>
>
> After long investigation we found a Problem in Kafka.
> When a __consumer_offsets partition gets segmented and Kafka is restarted and
> needs to reload offsets, consumers will start at a wrong position when
> metadata and offset events are in both segments.
> Reproduction:
> 1.) Start zookeeper and kafka as is from the archive
> {code}
> KAFKA_HEAP_OPTS="-Xmx256M -Xms256M" bin/zookeeper-server-start.sh
> config/zookeeper.properties
> KAFKA_HEAP_OPTS="-Xmx256M -Xms256M" bin/kafka-server-start.sh
> config/server.properties
> {code}
> 2.) Start [^KafkaErrorProducer.java] which adds 1M log entries to the topic
> test
> 3.) Start [^KafkaErrorConsumer.java] which starts a consumer, reads 100
> entries one by one and then closes the consumer. This leads to a 2nd segment
> in /tmp/kafka-logs/__consumer_offsets-27. This step takes some time (around
> 5mins). The close of the consumer is needed to have metadata events in the
> segments too.
> 4.) Stop and restart the Kafka broker
> 5.) Start any consumer on topic test and group testgroup
> {code}
> bin/kafka-console-consumer.sh --from-beginning --bootstrap-server
> localhost:9092 --topic test --consumer-property group.id=testgroup
> {code}
> Is:
> the consumer starts at the segmentation boundary
> Expected:
> the consumer starts at the end
> The Reason for this behavior is the closing brace of the while loop in
> GroupMetadataManager#loadGroupsAndOffsets at a wrong position introduced with
> commit
> https://github.com/apache/kafka/commit/5bd06f1d542e6b588a1d402d059bc24690017d32
> I will prepare a pull request.
> *Edit*: The issue can happen if there are multiple reads from the same
> segment, see https://github.com/apache/kafka/pull/3538#discussion_r127759694
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