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Posted to dev@kafka.apache.org by "Manikumar (JIRA)" <ji...@apache.org> on 2018/05/07 06:55:00 UTC
[jira] [Resolved] (KAFKA-3921) Periodic refresh of metadata causes
spurious log messages
[ https://issues.apache.org/jira/browse/KAFKA-3921?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Manikumar resolved KAFKA-3921.
------------------------------
Resolution: Auto Closed
Closing inactive issue. The old producer is no longer supported. Please upgrade to the Java producer whenever possible.
> Periodic refresh of metadata causes spurious log messages
> ---------------------------------------------------------
>
> Key: KAFKA-3921
> URL: https://issues.apache.org/jira/browse/KAFKA-3921
> Project: Kafka
> Issue Type: Improvement
> Components: clients
> Affects Versions: 0.9.0.1
> Reporter: Steven Schlansker
> Priority: Major
>
> Kafka cluster metadata has a configurable expiry period. (I don't understand why this is -- cluster updates can happen at any time, and we have to pick those up quicker than every 10 minutes? But this ticket isn't about that.)
> When this interval expires, the ClientUtils class spins up a SyncProducer, which sends a special message to retrieve metadata. The producer is then closed immediately after processing this message.
> This causes the SyncProducer to log both a connection open and close at INFO level:
> {code}
> 2016-06-30T17:50:19.408Z INFO <> [ProducerSendThread-central-buzzsaw-1-myhost] kafka.client.ClientUtils$ - Fetching metadata from broker BrokerEndPoint(2,broker-3.mycorp.com,9092) with correlation id 17188 for 1 topic(s) Set(logstash)
> 2016-06-30T17:50:19.410Z INFO <> [ProducerSendThread-central-buzzsaw-1-myhost] kafka.producer.SyncProducer - Connected to broker-3.mycorp.com:9092 for producing
> 2016-06-30T17:50:19.411Z INFO <> [ProducerSendThread-central-buzzsaw-1-myhost] kafka.producer.SyncProducer - Disconnecting from broker-3.mycorp.com:9092
> 2016-06-30T17:50:19.411Z INFO <> [ProducerSendThread-central-buzzsaw-1-myhost] kafka.producer.SyncProducer - Disconnecting from broker-14.mycorp.com:9092
> 2016-06-30T17:50:19.411Z INFO <> [ProducerSendThread-central-buzzsaw-1-myhost] kafka.producer.SyncProducer - Disconnecting from broker-logkafka-13.mycorp.com:9092
> 2016-06-30T17:50:19.411Z INFO <> [ProducerSendThread-central-buzzsaw-1-myhost] kafka.producer.SyncProducer - Disconnecting from broker-12.mycorp.com:9092
> 2016-06-30T17:50:19.413Z INFO <> [ProducerSendThread-central-buzzsaw-1-myhost] kafka.producer.SyncProducer - Connected to broker-12.mycorp.com:9092 for producing
> {code}
> When you are reading the logs, this appears periodically. We've had more than one administrator then think that the cluster is unhealthy, and client connections are getting dropped -- it's disconnecting from the broker so frequently! What is wrong??? But in reality, it is just this harmless / expected metadata update.
> Can we tweak the log levels so that the periodic background refresh does not log unless something goes wrong? The log messages are misleading and easy to misinterpret. I had to read the code pretty thoroughly to convince myself that these messages are actually harmless.
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