Kafka:不断获取FETCH_SESSION_ID_NOT_FOUND

Question

我一直在获取FETCH_SESSION_ID_NOT_FOUND。我不知道为什么会这样。谁能在这里请我，问题是什么，将对消费者和经纪人产生什么影响。

Kafka服务器日志：

INFO [2019-10-18 12:09:00,709] [ReplicaFetcherThread-1-8][] org.apache.kafka.clients.FetchSessionHandler - [ReplicaFetcher replicaId=6, leaderId=8, fetcherId=1] Node 8 was unable to process the fetch request with (sessionId=258818904, epoch=2233): FETCH_SESSION_ID_NOT_FOUND.
 INFO [2019-10-18 12:09:01,078] [ReplicaFetcherThread-44-10][] org.apache.kafka.clients.FetchSessionHandler - [ReplicaFetcher replicaId=6, leaderId=10, fetcherId=44] Node 10 was unable to process the fetch request with (sessionId=518415741, epoch=4416): FETCH_SESSION_ID_NOT_FOUND.
 INFO [2019-10-18 12:09:01,890] [ReplicaFetcherThread-32-9][] org.apache.kafka.clients.FetchSessionHandler - [ReplicaFetcher replicaId=6, leaderId=9, fetcherId=32] Node 9 was unable to process the fetch request with (sessionId=418200413, epoch=3634): FETCH_SESSION_ID_NOT_FOUND.

Kafka消费者日志：

12:29:58,936 INFO  [FetchSessionHandler:383] [Consumer clientId=bannerGroupMap#87e2af7cf742#test, groupId=bannerGroupMap#87e2af7cf742#test] Node 8 was unable to process the fetch request with (sessionId=1368981303, epoch=60): FETCH_SESSION_ID_NOT_FOUND.
12:29:58,937 INFO  [FetchSessionHandler:383] [Consumer clientId=bannerGroupMap#87e2af7cf742#test, groupId=bannerGroupMap#87e2af7cf742#test] Node 3 was unable to process the fetch request with (sessionId=1521862194, epoch=59): FETCH_SESSION_ID_NOT_FOUND.
12:29:59,939 INFO  [FetchSessionHandler:383] [Consumer clientId=zoneGroupMap#87e2af7cf742#test, groupId=zoneGroupMap#87e2af7cf742#test] Node 7 was unable to process the fetch request with (sessionId=868804875, epoch=58): FETCH_SESSION_ID_NOT_FOUND.
12:30:06,952 INFO  [FetchSessionHandler:383] [Consumer clientId=creativeMap#87e2af7cf742#test, groupId=creativeMap#87e2af7cf742#test] Node 3 was unable to process the fetch request with (sessionId=1135396084, epoch=58): FETCH_SESSION_ID_NOT_FOUND.
12:30:12,965 INFO  [FetchSessionHandler:383] [Consumer clientId=creativeMap#87e2af7cf742#test, groupId=creativeMap#87e2af7cf742#test] Node 6 was unable to process the fetch request with (sessionId=1346340004, epoch=56): FETCH_SESSION_ID_NOT_FOUND.

集群详细信息：

Broker: 13 (1 Broker : 14 cores & 36GB memory)
Kafka cluster version: 2.0.0
Kafka Java client version: 2.0.0
Number topics: ~15. 
Number of consumers: 7K (all independent and manually assigned all partitions of a topic to a consumers. One consumer is consuming all partitions from a topic only) 

Answer 1

增加max.incremental.fetch.session.cache.slots的值。默认值是1K，在我的例子中，我将其增加到10K，并将其修复。

Answer 2

这不是一个错误，它是一个信息，它告诉你你已连接，但它无法获取会话id，因为没有会话id可获取。

在日志中看到此消息和刷新消息是正常的。

Answer 3

我一开始把它从1K增加到2K，第二步从2K增加到4K，只要限制没有用完，就没有出现错误：

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在我看来，这像是某个身份不明的消费者的会话泄露，我还没有尝试10K限制，但读了Hrishikesh Mishra的回答，我肯定会的。因为增加限制也会降低出错的频率，所以识别打开过多增量获取会话的单个消费组的问题，这里提到的How to check the actual number of incremental fetch session cache slots used in Kafka cluster?，最终可能是无关紧要的。