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Peter Sinoros-Szabo commented on KAFKA-12431: --------------------------------------------- The change was probably introduced in 2.5.0 or 2.5.1 because I saw the same behaviour with 2.5.1 too. I didn't test it with 2.5.0. > Fetch Request/Response without Topic information > ------------------------------------------------ > > Key: KAFKA-12431 > URL: https://issues.apache.org/jira/browse/KAFKA-12431 > Project: Kafka > Issue Type: Bug > Affects Versions: 2.6.1 > Reporter: Peter Sinoros-Szabo > Priority: Major > Attachments: fetch-on-2.4.1.png, fetch-on-2.6.1.png, > kafka-highcpu-24.svg.zip, kafka-highcpu-26.svg.zip > > > I was running a 6 node Kafka 2.4.1 cluster with protocol and message format > version set to 2.4. I wanted to upgrade the cluster to 2.6.1 and after I > upgraded the 1st broker to 2.6.1 without any configuration change, I noticed > much higher CPU usage on that broker (instead of 25% CPU usage it was ~350%) > and about 3-4x higher network traffic. So I dumped the traffic between the > Kafka client and broker and compared it with the traffic of the same broker > downgraded to 2.4.1. > It seems to me that after I upgraded to 2.6.1, the Fetch requests and > responses are not complete, it is missing the topics part of the Fetch > Request, I don't know for what reason. I guess there should be always a > topics part. > I'll attache a screenshot from these messages. > -- This message was sent by Atlassian Jira (v8.3.4#803005)