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https://issues.apache.org/jira/browse/KAFKA-2350?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14634114#comment-14634114
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Gwen Shapira commented on KAFKA-2350:
-------------------------------------
Cool feature :)
Can you clarify: " If you skip poll() ... then a rebalance will be triggered "
When does a delay count as skipping? Are we obligated to do the next poll()
immediately after the first one ended?
I expect to use the consumer to do something like:
"poll until I get N messages, write those messages elsewhere, poll again".
If the "write messages elsewhere" takes longer than expected (DB is busy kinda
scenario), the consumer will lose the partitions?
(sorry if I missed important discussion elsewhere, feel free to refer me to
another JIRA or thread)
> Add KafkaConsumer pause capability
> ----------------------------------
>
> Key: KAFKA-2350
> URL: https://issues.apache.org/jira/browse/KAFKA-2350
> Project: Kafka
> Issue Type: Improvement
> Reporter: Jason Gustafson
> Assignee: Jason Gustafson
>
> There are some use cases in stream processing where it is helpful to be able
> to pause consumption of a topic. For example, when joining two topics, you
> may need to delay processing of one topic while you wait for the consumer of
> the other topic to catch up. The new consumer currently doesn't provide a
> nice way to do this. If you skip poll() or if you unsubscribe, then a
> rebalance will be triggered and your partitions will be reassigned.
> One way to achieve this would be to add two new methods to KafkaConsumer:
> {code}
> void pause(String... topics);
> void unpause(String... topics);
> {code}
> When a topic is paused, a call to KafkaConsumer.poll will not initiate any
> new fetches for that topic. After it is unpaused, fetches will begin again.
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