Hi, I have the 3 consumers subscribing from a single topic with the following settings.
auto.commit.interval.ms = 1000 enable.auto.commit = true request.timeout.ms = 60000 session.timeout.ms = 59000 heartbeat.interval.ms = 4000 Version 0.9.0. The consumers looks like this: while (isRunning()) { ConsumerRecords<String, byte[]> records = consumer.poll(3000); for (final ConsumerRecord<String, byte[]> record : records) { doWork(...); } if (!records.isEmpty()) { log.info(String.format("Committed(Records = '%d', Offset = '%d', Time = '%dms')", records.count(), Iterables.getLast(records).offset(), TimeUnit.MILLISECONDS.convert(elapsedTime, TimeUnit.NANOSECONDS))); } } My problem is that the offset sometimes is moved back a lot during a rebalance. This is the log from the consumers during a rebalance. Consumer 1: [2016-03-17 04:06:55,823] Committed(Records = '4', Offset = '427432', Time = '3090ms') [2016-03-17 04:06:55,823] org.apache.kafka.clients.consumer.internals.ConsumerCoordinator: Error UNKNOWN_MEMBER_ID occurred while committing offsets for group default [2016-03-17 04:06:55,823] org.apache.kafka.clients.consumer.internals.ConsumerCoordinator: Auto offset commit failed: Commit cannot be completed due to group rebalance [2016-03-17 04:06:55,824] org.apache.kafka.clients.consumer.internals.ConsumerCoordinator: Error UNKNOWN_MEMBER_ID occurred while committing offsets for group default [2016-03-17 04:06:55,824] org.apache.kafka.clients.consumer.internals.ConsumerCoordinator: Auto offset commit failed: Commit cannot be completed due to group rebalance [2016-03-17 04:06:55,825] org.apache.kafka.clients.consumer.internals.ConsumerCoordinator: Error UNKNOWN_MEMBER_ID occurred while committing offsets for group default [2016-03-17 04:06:55,825] org.apache.kafka.clients.consumer.internals.ConsumerCoordinator: Auto offset commit failed: [2016-03-17 04:06:55,825] org.apache.kafka.clients.consumer.internals.AbstractCoordinator: Attempt to join group default failed due to unknown member id, resetting and retrying. [2016-03-17 04:07:11,463] Committed(Records = '4', Offset = '427412', Time = '1ms') Offset before rebalance: 427432 Offset after rebalance: 427412 Diff: 20 Consumer 2: INFO [2016-03-17 04:06:52,299] Committed(Records = '1', Offset = '427444', Time = '0ms') INFO [2016-03-17 04:06:52,573] org.apache.kafka.clients.consumer.internals.AbstractCoordinator: Attempt to heart beat failed since the group is rebalancing, try to re-join group. INFO [2016-03-17 04:07:11,464] Committed(Records = '4', Offset = '427430', Time = '0ms') Offset before rebalance: 427444 Offset after rebalance: 427430 Diff: 14 Consumer 3: [2016-03-17 04:07:07,254] Committed(Records = '4', Offset = '427408', Time = '1674ms') [2016-03-17 04:07:07,254] org.apache.kafka.clients.consumer.internals.AbstractCoordinator: Attempt to heart beat failed since the group is rebalancing, try to re-join group. [2016-03-17 04:07:13,811] Committed(Records = '4', Offset = '412777', Time = '2345ms') Offset before rebalance: 427410 Offset after rebalance: 412777 Diff: 14 633. This is causing trouble for me. Any idea on what I'm doing wrong?