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https://issues.apache.org/jira/browse/KAFKA-10254?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17154725#comment-17154725
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Arvin Zheng commented on KAFKA-10254:
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[~xiaotong.wang], see KAFKA-10134
> 100% cpu usage by kafkaConsumer poll , when broker can‘t be connect
> --------------------------------------------------------------------
>
> Key: KAFKA-10254
> URL: https://issues.apache.org/jira/browse/KAFKA-10254
> Project: Kafka
> Issue Type: Bug
> Components: clients
> Affects Versions: 2.5.0
> Reporter: xiaotong.wang
> Priority: Critical
> Attachments: image-2020-07-09-19-24-20-604.png
>
>
> steps
> 1、start kafka broker
> 2、start kafka consumer and subscribe some topic with some kafkaConsumer
> instance and call kafkaConsumer.*poll(Duration.ofMillis(pollTimeout))*
> and set auto.commit.enabled=false
> 3、iptables to disable kafka broker ip in client vm or shutdown kafka brokers
> 4、cpu go to 100%
>
> *why?*
>
>
> left Vserison :2.3.1
> right Version:2.5.0
>
> for 2.3.1 kafkaConsumer when kafka brokers go
> down,updateAssignmentMetadataIfNeeded will block x ms and return empty
> records ,
> !image-2020-07-09-19-24-20-604.png|width=926,height=164!
>
> for 2.5.0
> private Map<TopicPartition, List<ConsumerRecord<K, V>>> pollForFetches(Timer
> timer) {
> *long pollTimeout = coordinator == null ? timer.remainingMs() :*
> *Math.min(coordinator.timeToNextPoll(timer.currentTimeMs()),
> timer.remainingMs());*
> i check the source of kafka client ,poll timeout will be change to 0 ms ,when
> heartbeat timeout ，so it will call poll without any block ,this will cause
> cpu go to 100%
>
>
>
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