我正在使用kafka connector confluent 3.0.1版本。我创建了一个名为new group的新组，上面有大约20个主题。这些主题中的大部分都很忙。但遗憾的是，当我启动connector框架时，系统无法停止重新平衡，大约2分钟左右所有主题的重新平衡。我不知道原因。一些错误消息是：

[2017-01-03 21:43:57,718] ERROR Commit of WorkerSinkTask{id=new-connector-0} offsets threw an unexpected exception:  (org.apache.kafka.connect.runtime.WorkerSinkTask:180)
org.apache.kafka.clients.consumer.CommitFailedException: Commit cannot be completed since the group has already rebalanced and assigned the partitions to another member. This means that the time between subsequent calls to poll() was longer than the configured session.timeout.ms, which typically implies that the poll loop is spending too much time message processing. You can address this either by increasing the session timeout or by reducing the maximum size of batches returned in poll() with max.poll.records.
        at org.apache.kafka.clients.consumer.internals.ConsumerCoordinator$OffsetCommitResponseHandler.handle(ConsumerCoordinator.java:578)
        at org.apache.kafka.clients.consumer.internals.ConsumerCoordinator$OffsetCommitResponseHandler.handle(ConsumerCoordinator.java:519)
        at org.apache.kafka.clients.consumer.internals.AbstractCoordinator$CoordinatorResponseHandler.onSuccess(AbstractCoordinator.java:679)
        at org.apache.kafka.clients.consumer.internals.AbstractCoordinator$CoordinatorResponseHandler.onSuccess(AbstractCoordinator.java:658)
        at org.apache.kafka.clients.consumer.internals.RequestFuture$1.onSuccess(RequestFuture.java:167)
        at org.apache.kafka.clients.consumer.internals.RequestFuture.fireSuccess(RequestFuture.java:133)
        at org.apache.kafka.clients.consumer.internals.RequestFuture.complete(RequestFuture.java:107)
        at org.apache.kafka.clients.consumer.internals.ConsumerNetworkClient$RequestFutureCompletionHandler.onComplete(ConsumerNetworkClient.java:426)
        at org.apache.kafka.clients.NetworkClient.poll(NetworkClient.java:278)
        at org.apache.kafka.clients.consumer.internals.ConsumerNetworkClient.clientPoll(ConsumerNetworkClient.java:360)
        at org.apache.kafka.clients.consumer.internals.ConsumerNetworkClient.poll(ConsumerNetworkClient.java:224)
        at org.apache.kafka.clients.consumer.internals.ConsumerNetworkClient.poll(ConsumerNetworkClient.java:192)
        at org.apache.kafka.clients.consumer.internals.ConsumerNetworkClient.poll(ConsumerNetworkClient.java:163)
        at org.apache.kafka.clients.consumer.internals.ConsumerCoordinator.commitOffsetsSync(ConsumerCoordinator.java:404)
        at org.apache.kafka.clients.consumer.KafkaConsumer.commitSync(KafkaConsumer.java:1058)
        at org.apache.kafka.connect.runtime.WorkerSinkTask.doCommit(WorkerSinkTask.java:247)
        at org.apache.kafka.connect.runtime.WorkerSinkTask.commitOffsets(WorkerSinkTask.java:293)
        at org.apache.kafka.connect.runtime.WorkerSinkTask.closePartitions(WorkerSinkTask.java:421)
        at org.apache.kafka.connect.runtime.WorkerSinkTask.access$1100(WorkerSinkTask.java:54)
        at org.apache.kafka.connect.runtime.WorkerSinkTask$HandleRebalance.onPartitionsRevoked(WorkerSinkTask.java:465)
        at org.apache.kafka.clients.consumer.internals.ConsumerCoordinator.onJoinPrepare(ConsumerCoordinator.java:283)
        at org.apache.kafka.clients.consumer.internals.AbstractCoordinator.ensureActiveGroup(AbstractCoordinator.java:212)
        at org.apache.kafka.clients.consumer.internals.ConsumerCoordinator.ensurePartitionAssignment(ConsumerCoordinator.java:345)
        at org.apache.kafka.clients.consumer.KafkaConsumer.pollOnce(KafkaConsumer.java:977)
        at org.apache.kafka.clients.consumer.KafkaConsumer.poll(KafkaConsumer.java:937)
        at org.apache.kafka.connect.runtime.WorkerSinkTask.pollConsumer(WorkerSinkTask.java:305)
        at org.apache.kafka.connect.runtime.WorkerSinkTask.poll(WorkerSinkTask.java:222)
        at org.apache.kafka.connect.runtime.WorkerSinkTask.iteration(WorkerSinkTask.java:170)
        at org.apache.kafka.connect.runtime.WorkerSinkTask.execute(WorkerSinkTask.java:142)
        at org.apache.kafka.connect.runtime.WorkerTask.doRun(WorkerTask.java:140)
        at org.apache.kafka.connect.runtime.WorkerTask.run(WorkerTask.java:175)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
:

我不知道这是否与持续的再平衡有关。
我知道如果kafkaconsumer.poll（）比配置的超时时间长，kafka会撤销分区，从而触发重新平衡，但是我很确定每次的poll都不会那么长。有人能给我一些线索吗？