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https://issues.apache.org/jira/browse/KAFKA-16012?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Justine Olshan resolved KAFKA-16012.
------------------------------------
Resolution: Fixed
> Incomplete range assignment in consumer
> ---------------------------------------
>
> Key: KAFKA-16012
> URL: https://issues.apache.org/jira/browse/KAFKA-16012
> Project: Kafka
> Issue Type: Bug
> Reporter: Jason Gustafson
> Assignee: Philip Nee
> Priority: Blocker
> Fix For: 3.7.0
>
>
> We were looking into test failures here:
> https://confluent-kafka-branch-builder-system-test-results.s3-us-west-2.amazonaws.com/system-test-kafka-branch-builder--1702475525--jolshan--kafka-15784--7cad567675/2023-12-13--001./2023-12-13–001./report.html.
>
> Here is the first failure in the report:
> {code:java}
> ====================================================================================================
> test_id:
> kafkatest.tests.core.group_mode_transactions_test.GroupModeTransactionsTest.test_transactions.failure_mode=clean_bounce.bounce_target=brokers
> status: FAIL
> run time: 3 minutes 4.950 seconds
> TimeoutError('Consumer consumed only 88223 out of 100000 messages in
> 90s') {code}
>
> We traced the failure to an apparent bug during the last rebalance before the
> group became empty. The last remaining instance seems to receive an
> incomplete assignment which prevents it from completing expected consumption
> on some partitions. Here is the rebalance from the coordinator's perspective:
> {code:java}
> server.log.2023-12-13-04:[2023-12-13 04:58:56,987] INFO [GroupCoordinator 3]:
> Stabilized group grouped-transactions-test-consumer-group generation 5
> (__consumer_offsets-2) with 1 members
> (kafka.coordinator.group.GroupCoordinator)
> server.log.2023-12-13-04:[2023-12-13 04:58:56,990] INFO [GroupCoordinator 3]:
> Assignment received from leader
> consumer-grouped-transactions-test-consumer-group-1-2164f472-93f3-4176-af3f-23d4ed8b37fd
> for group grouped-transactions-test-consumer-group for generation 5. The
> group has 1 members, 0 of which are static.
> (kafka.coordinator.group.GroupCoordinator) {code}
> The group is down to one member in generation 5. In the previous generation,
> the consumer in question reported this assignment:
> {code:java}
> // Gen 4: we've got partitions 0-4
> [2023-12-13 04:58:52,631] DEBUG [Consumer
> clientId=consumer-grouped-transactions-test-consumer-group-1,
> groupId=grouped-transactions-test-consumer-group] Executing onJoinComplete
> with generation 4 and memberId
> consumer-grouped-transactions-test-consumer-group-1-2164f472-93f3-4176-af3f-23d4ed8b37fd
> (org.apache.kafka.clients.consumer.internals.ConsumerCoordinator)
> [2023-12-13 04:58:52,631] INFO [Consumer
> clientId=consumer-grouped-transactions-test-consumer-group-1,
> groupId=grouped-transactions-test-consumer-group] Notifying assignor about
> the new Assignment(partitions=[input-topic-0, input-topic-1, input-topic-2,
> input-topic-3, input-topic-4])
> (org.apache.kafka.clients.consumer.internals.ConsumerCoordinator) {code}
> However, in generation 5, we seem to be assigned only one partition:
> {code:java}
> // Gen 5: Now we have only partition 1? But aren't we the last member in the
> group?
> [2023-12-13 04:58:56,954] DEBUG [Consumer
> clientId=consumer-grouped-transactions-test-consumer-group-1,
> groupId=grouped-transactions-test-consumer-group] Executing onJoinComplete
> with generation 5 and memberId
> consumer-grouped-transactions-test-consumer-group-1-2164f472-93f3-4176-af3f-23d4ed8b37fd
> (org.apache.kafka.clients.consumer.internals.ConsumerCoordinator)
> [2023-12-13 04:58:56,955] INFO [Consumer
> clientId=consumer-grouped-transactions-test-consumer-group-1,
> groupId=grouped-transactions-test-consumer-group] Notifying assignor about
> the new Assignment(partitions=[input-topic-1])
> (org.apache.kafka.clients.consumer.internals.ConsumerCoordinator) {code}
> The assignment type is range from the JoinGroup for generation 5. The decoded
> metadata sent by the consumer is this:
> {code:java}
> Subscription(topics=[input-topic], ownedPartitions=[], groupInstanceId=null,
> generationId=4, rackId=null) {code}
> Here is the decoded assignment from the SyncGroup:
> {code:java}
> Assignment(partitions=[input-topic-1]) {code}
>
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