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https://issues.apache.org/jira/browse/KAFKA-2686?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Guozhang Wang reassigned KAFKA-2686:
------------------------------------

    Assignee: Guozhang Wang  (was: Neha Narkhede)

> unsubscribe() call leaves KafkaConsumer in invalid state for manual 
> topic-partition assignment
> ----------------------------------------------------------------------------------------------
>
>                 Key: KAFKA-2686
>                 URL: https://issues.apache.org/jira/browse/KAFKA-2686
>             Project: Kafka
>          Issue Type: Bug
>          Components: consumer
>    Affects Versions: 0.9.0.0
>            Reporter: The Data Lorax
>            Assignee: Guozhang Wang
>
> The bellow code snippet demonstrated the problem.
> Basically, the unsubscribe() call leaves the KafkaConsumer in a state that 
> means poll() will always return empty record sets, even if new 
> topic-partitions have been assigned that have messages pending.  This is 
> because unsubscribe() sets SubscriptionState.needsPartitionAssignment to 
> true, and assign() does not clear this flag. The only thing that clears this 
> flag is when the consumer handles the response from a JoinGroup request.
> {code}
> final KafkaConsumer<String, String> consumer = new KafkaConsumer<>(props);
> consumer.assign(Collections.singletonList(new TopicPartition(topicName, 1)));
> ConsumerRecords<String, String> records = consumer.poll(100);// <- Works, 
> returning records
> consumer.unsubscribe();   // Puts consumer into invalid state.
> consumer.assign(Collections.singletonList(new TopicPartition(topicName, 2)));
> records = consumer.poll(100);// <- Always returns empty record set.
> {code}



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