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https://issues.apache.org/jira/browse/KAFKA-3921?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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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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