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https://issues.apache.org/jira/browse/KAFKA-3854?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15359943#comment-15359943
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ASF GitHub Bot commented on KAFKA-3854:
---------------------------------------
GitHub user vahidhashemian reopened a pull request:
https://github.com/apache/kafka/pull/1572
KAFKA-3854: Fix issues with new consumer's subsequent regex (pattern)
subscriptions
This patch fixes two issues:
1. Subsequent regex subscriptions fail with the new consumer.
2. Subsequent regex subscriptions would not immediately refresh metadata to
change the subscription of the new consumer and trigger a rebalance.
The final note on the JIRA stating that a later created topic that matches
a consumer's subscription pattern would not be assigned to the consumer upon
creation seems to be as designed. A repeat
`subscribe()` to the same pattern or some wait time until the next
automatic metadata refresh would handle that case.
An integration test was also added to verify these issues are fixed with
this PR.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/vahidhashemian/kafka KAFKA-3854
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/kafka/pull/1572.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #1572
----
commit 0860bd7691b87de33393b26373df752b0d2f934e
Author: Vahid Hashemian <vahidhashem...@us.ibm.com>
Date: 2016-06-16T21:19:32Z
KAFKA-3854: Fix issues with new consumer's subsequent regex (pattern)
subscriptions
This patch fixes two issues:
1. Subsequent regex subscriptions fail with the new consumer.
2. Subsequent regex subscriptions would not actually refresh metadata and
change the subscription of the new consumer nor they would trigger a rebalance.
The final note on the JIRA stating that a later created topic that matches
a consumer's subscription pattern would not be assigned to the consumer upon
creation seems to be as designed. A repeat subscribe() to the same pattern
would be needed to handle that case.
Unit tests for regex subscriptions will be handled in KAFKA-3897.
----
> 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 Subscription Change and
> Rebalance
> Even after the code is tweaked to get around the above issue, only the first
> call to regex subscription triggers an actual subscription and 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.
> It seems due to the same reason, if a consumer is subscribed to a pattern,
> and later on a new topic is created that matches that pattern, the consumer
> does not become subscribed it.
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