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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. -- This message was sent by Atlassian JIRA (v7.6.3#76005)