[jira] [Assigned] (KAFKA-16556) Race condition between ConsumerRebalanceListener and SubscriptionState

["Kirk True (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/KAFKA-16556?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Kirk True reassigned KAFKA-16556:
---------------------------------

    Assignee: Kirk True

> Race condition between ConsumerRebalanceListener and SubscriptionState
> ----------------------------------------------------------------------
>
>                 Key: KAFKA-16556
>                 URL: https://issues.apache.org/jira/browse/KAFKA-16556
>             Project: Kafka
>          Issue Type: Bug
>          Components: clients, consumer
>    Affects Versions: 3.7.0
>            Reporter: Kirk True
>            Assignee: Kirk True
>            Priority: Blocker
>              Labels: kip-848-client-support
>             Fix For: 3.8.0
>
>
> There appears to be a race condition between invoking the {{ConsumerRebalanceListener}} callbacks on reconciliation and {{initWithCommittedOffsetsIfNeeded}} in the consumer.
>  
> The membership manager adds the newly assigned partitions to the {{{}SubscriptionState{}}}, but marks them as {{{}pendingOnAssignedCallback{}}}. Then, after the {{ConsumerRebalanceListener.onPartitionsAssigned()}} completes, the membership manager will invoke {{enablePartitionsAwaitingCallback}} to set all of those partitions' 'pending' flag to false.
>  
> During the main {{Consumer.poll()}} loop, {{AsyncKafkaConsumer}} may need to call {{initWithCommittedOffsetsIfNeeded()}} if the positions aren't already cached. Inside {{{}initWithCommittedOffsetsIfNeeded{}}}, the consumer calls the subscription's {{initializingPartitions}} method to get a set of the partitions for which to fetch their committed offsets. However, {{SubscriptionState.initializingPartitions()}} only returns partitions that have the {{pendingOnAssignedCallback}} flag set to to false.
>  
> The result is: * If the {{MembershipManagerImpl.assignPartitions()}} future  is completed on the background thread first, the 'pending' flag is set to false. On the application thread, when {{SubscriptionState.initializingPartitions()}} is called, it returns the partition, and we fetch its committed offsets
>  * If instead the application thread calls {{SubscriptionState.initializingPartitions()}} first, the partitions's 'pending' flag is still set to false, and so the partition is omitted from the returned set. The {{updateFetchPositions()}} method then continues on and re-initializes the partition's fetch offset to 0.



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