[jira] [Resolved] (KAFKA-7112) StreamThread does not check for state again after pollRequests()

["Rajini Sivaram (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/KAFKA-7112?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Rajini Sivaram resolved KAFKA-7112.
-----------------------------------
       Resolution: Fixed
    Fix Version/s: 2.0.0

> StreamThread does not check for state again after pollRequests()
> ----------------------------------------------------------------
>
>                 Key: KAFKA-7112
>                 URL: https://issues.apache.org/jira/browse/KAFKA-7112
>             Project: Kafka
>          Issue Type: Bug
>          Components: streams
>            Reporter: Guozhang Wang
>            Assignee: Guozhang Wang
>            Priority: Major
>             Fix For: 2.0.0
>
>
> In StreamThread's main loop, we have:
> {code}
>         if (state == State.PARTITIONS_ASSIGNED) {
>             // try to fetch some records with zero poll millis
>             // to unblock the restoration as soon as possible
>             records = pollRequests(Duration.ZERO);
>             if (taskManager.updateNewAndRestoringTasks()) {
>                 setState(State.RUNNING);
>             }
>         }
> {code}
> in which we first check for state, and if it is {{PARTITIONS_ASSIGNED}} then call `consumer.poll()` and then call `askManager.updateNewAndRestoringTasks()`. There is a race condition though, that if another rebalance gets triggered, then `onPartitionRevoked` will be called in which we will {{restoreConsumer.unsubscribe();}}, and then if we call {{taskManager.updateNewAndRestoringTasks()}} right away we will see this:
> {code}
> Encountered the following error during processing: (org.apache.kafka.streams.processor.internals.StreamThread)
> java.lang.IllegalStateException: Consumer is not subscribed to any topics or assigned any partitions
>         at org.apache.kafka.clients.consumer.KafkaConsumer.poll(KafkaConsumer.java:1159)
>         at org.apache.kafka.clients.consumer.KafkaConsumer.poll(KafkaConsumer.java:1150)
>         at org.apache.kafka.streams.processor.internals.StoreChangelogReader.restore(StoreChangelogReader.java:83)
>         at org.apache.kafka.streams.processor.internals.TaskManager.updateNewAndRestoringTasks(TaskManager.java:317)
>         at org.apache.kafka.streams.processor.internals.StreamThread.runOnce(StreamThread.java:808)
>         at org.apache.kafka.streams.processor.internals.StreamThread.runLoop(StreamThread.java:767)
>         at org.apache.kafka.streams.processor.internals.StreamThread.run(StreamThread.java:736)
> {code}



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