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https://issues.apache.org/jira/browse/KAFKA-3854?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Vahid Hashemian updated KAFKA-3854:
-----------------------------------
    Summary: Subsequent regex subscription calls fail  (was: Consecutive regex 
subscription calls fail)

> Subsequent regex subscription calls fail
> ----------------------------------------
>
>                 Key: KAFKA-3854
>                 URL: https://issues.apache.org/jira/browse/KAFKA-3854
>             Project: Kafka
>          Issue Type: Bug
>          Components: consumer
>            Reporter: Vahid Hashemian
>            Assignee: Vahid Hashemian
>
> There are a couple of issues with regex subscription in the new consumer:
> h6. Subsequent Subscriptions Fail
> When consecutive calls are made to new consumer's [regex 
> subscription|https://github.com/apache/kafka/blob/trunk/clients/src/main/java/org/apache/kafka/clients/consumer/KafkaConsumer.java#L850],
>  like below: 
> {code}
> consumer.subscribe(Pattern.compile("..."), listener);
> consumer.poll(0);
> consumer.subscribe(Pattern.compile("f.."), listener);
> consumer.poll(0);
> {code}
> the second call fails with the following error:
> {code}
> Exception in thread "main" java.lang.IllegalStateException: Subscription to 
> topics, partitions and pattern are mutually exclusive
>       at 
> org.apache.kafka.clients.consumer.internals.SubscriptionState.subscribe(SubscriptionState.java:175)
>       at 
> org.apache.kafka.clients.consumer.KafkaConsumer.subscribe(KafkaConsumer.java:854)
>       ...
> {code}
> h6. Subsequent Subscriptions Fail to Trigger a Rebalance
> Even after the code is tweaked to get around the above issue, only the first 
> call to regex subscription triggers the subscription's rebalance listener. 
> The reason is the regex {{subscription}} / {{poll}} does not directly call 
> {{changeSubscription(...)}} in which {{needsPartitionAssignment}} is set and 
> causes a rebalance. This method is called only during the first regex 
> {{subscription}} / {{poll}} when coordinator is unknown and [a 
> {{client.poll}} 
> call|https://github.com/apache/kafka/blob/trunk/clients/src/main/java/org/apache/kafka/clients/consumer/internals/AbstractCoordinator.java#L179]
>  is made which eventually leads to [a {{changeSubscription}} 
> call|https://github.com/apache/kafka/blob/trunk/clients/src/main/java/org/apache/kafka/clients/consumer/internals/ConsumerCoordinator.java#L161].
>  The subsequent call does not reach this point because the coordinator is 
> already known.



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