[KAFKA-12186] TotalFetchRequestsPerSec not equal to sum of Fetch and FetchFollower Request Rate

• Type: Bug
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Affects Version/s: 2.1.1, 2.7.0
• Component/s: metrics, network
• Assignee: Unassigned
• Reporter: zhifeng.peng
• Created: 13/Jan/21 10:58
• Updated: 13/Jan/21 11:11

Description

TotalFetchRequestsPerSec: kafka.server:type=BrokerTopicMetrics, name=TotalFetchRequestsPerSec

Fetch: kafka.network:type=RequestMetrics, name=RequestsPerSec, request=Fetch
FetchFollower: kafka.network:type=RequestMetrics, name=RequestsPerSec, request=FetchFollower

I found a big difference between TotalFetchRequestsPerSec and sum of Fetch and FetchFollower Request Rate. 
I don't know why topic-[2-10] has no Byte in/Out, but metric tell that TotalFetchRequestsPerSec of topic-[2-10] >0.

 

TotalFetchRequestsPerSec for all topic:

 

broker fetch and fetchFollower rate:

 

 

This is easy to reproduce, TotalFetchRequestsPerSec always more than sum of Fetch and FetchFollower rate.