Hi guys, I’m using kafka 0.9.0.1 and Java client. I saw the following exceptions throw by my consumer: Caused by: java.lang.IllegalStateException: Correlation id for response (767587) does not match request (767585) at org.apache.kafka.clients.NetworkClient.correlate(NetworkClient.java:477) at org.apache.kafka.clients.NetworkClient.handleCompletedReceives(NetworkClient.java:440) at org.apache.kafka.clients.NetworkClient.poll(NetworkClient.java:265) at org.apache.kafka.clients.consumer.internals.ConsumerNetworkClient.clientPoll(ConsumerNetworkClient.java:320) at org.apache.kafka.clients.consumer.internals.ConsumerNetworkClient.poll(ConsumerNetworkClient.java:213) at org.apache.kafka.clients.consumer.internals.ConsumerNetworkClient.poll(ConsumerNetworkClient.java:193) at org.apache.kafka.clients.consumer.KafkaConsumer.pollOnce(KafkaConsumer.java:908) at org.apache.kafka.clients.consumer.KafkaConsumer.poll(KafkaConsumer.java:853) at com.hulu.flintan.metadatacache.kafka.AssetChangeEventConsumer.run(AssetChangeEventConsumer.java:47) 35 seconds later, I started seeing
Error ILLEGAL_GENERATION occurred while committing offsets for group flintan-metadatacache-5b9d551b-bd4a-41fa-812f-3989c76c3856 happens all the time. I then checked the server side log, it shows [2016-11-17 06:17:28,868] INFO [GroupCoordinator 2]: Preparing to restabilize group flintan-metadatacache-5b9d551b-bd4a-41fa-812f-3989c76c3856 with old generation 1 (kafka.coordinator.GroupCoordinator) [2016-11-17 06:17:28,869] INFO [GroupCoordinator 2]: Group flintan-metadatacache-5b9d551b-bd4a-41fa-812f-3989c76c3856 generation 1 is dead and removed (kafka.coordinator.GroupCoordinator) [2016-11-17 06:17:42,396] INFO [GroupCoordinator 2]: Preparing to restabilize group flintan-metadatacache-5b9d551b-bd4a-41fa-812f-3989c76c3856 with old generation 0 (kafka.coordinator.GroupCoordinator) [2016-11-17 06:17:42,396] INFO [GroupCoordinator 2]: Stabilized group flintan-metadatacache-5b9d551b-bd4a-41fa-812f-3989c76c3856 generation 1 (kafka.coordinator.GroupCoordinator) [2016-11-17 06:17:42,399] INFO [GroupCoordinator 2]: Assignment received from leader for group flintan-metadatacache-5b9d551b-bd4a-41fa-812f-3989c76c3856 for generation 1 (kafka.coordinator.GroupCoordinator) [2016-11-17 06:18:12,404] INFO [GroupCoordinator 2]: Preparing to restabilize group flintan-metadatacache-5b9d551b-bd4a-41fa-812f-3989c76c3856 with old generation 1 (kafka.coordinator.GroupCoordinator) over and over all the time. It looks like the consumer group is bouncing between generation 0 and 1, and it stop consuming anything. This consumer group only have 1 consumer with it. We are using auto commit with interval 1000ms session timeout 30000ms heartbeat interval 3000ms My questions are: 1. Why this happens and how to prevent it happening again? 2. If it happens, how should I react in this case? Catch IllegalGeneration exception and resubscribe the topic? Or recreate the consumer w/ same (or different) consumer group id? 3. Where can I find the active consumer group for a topic? Does that store in zookeeper? Thanks, Jun