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https://issues.apache.org/jira/browse/KAFKA-12375?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17291331#comment-17291331
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A. Sophie Blee-Goldman commented on KAFKA-12375:
------------------------------------------------
Regarding the javax.management.InstanceAlreadyExistsException, this is
something I've seen in user logs and tests before. It's definitely a bit
confusing/potentially concerning to a user, but I don't think it's a new
problem. Maybe the REPLACE_THREAD functionality will have made it slightly more
common. Would be nice to fix, but I wouldn't press for that as a blocker of 2.8
> ReplaceStreamThread creates a new consumer with the same name as the one it's
> replacing
> ---------------------------------------------------------------------------------------
>
> Key: KAFKA-12375
> URL: https://issues.apache.org/jira/browse/KAFKA-12375
> Project: Kafka
> Issue Type: Bug
> Components: streams
> Affects Versions: 2.8.0
> Reporter: Tomasz Nguyen
> Assignee: Tomasz Nguyen
> Priority: Blocker
> Fix For: 2.8.0
>
>
> I was debugging the kafka-streams soak cluster and noticed that replacing a
> stream thread was causing the streams application to fail. I have managed to
> find the following stacktrace:
> {code:java}
> javax.management.InstanceAlreadyExistsException:
> kafka.consumer:type=app-info,id=i-0cdac8830ee1b8f01-StreamThread-1-restore-consumer
> at com.sun.jmx.mbeanserver.Repository.addMBean(Repository.java:437) at
> com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerWithRepository(DefaultMBeanServerInterceptor.java:1898)
> at
> com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerDynamicMBean(DefaultMBeanServerInterceptor.java:966)
> at
> com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerObject(DefaultMBeanServerInterceptor.java:900)
> at
> com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerMBean(DefaultMBeanServerInterceptor.java:324)
> at
> com.sun.jmx.mbeanserver.JmxMBeanServer.registerMBean(JmxMBeanServer.java:522)
> at
> org.apache.kafka.common.utils.AppInfoParser.registerAppInfo(AppInfoParser.java:64)
> at
> org.apache.kafka.clients.consumer.KafkaConsumer.<init>(KafkaConsumer.java:815)
> at
> org.apache.kafka.clients.consumer.KafkaConsumer.<init>(KafkaConsumer.java:666)
> at
> org.apache.kafka.streams.processor.internals.DefaultKafkaClientSupplier.getRestoreConsumer(DefaultKafkaClientSupplier.java:56)
> at
> org.apache.kafka.streams.processor.internals.StreamThread.create(StreamThread.java:338)
> at
> org.apache.kafka.streams.KafkaStreams.createAndAddStreamThread(KafkaStreams.java:896)
> at
> org.apache.kafka.streams.KafkaStreams.addStreamThread(KafkaStreams.java:977)
> at
> org.apache.kafka.streams.KafkaStreams.replaceStreamThread(KafkaStreams.java:467)
> at
> org.apache.kafka.streams.KafkaStreams.handleStreamsUncaughtException(KafkaStreams.java:487)
> at
> org.apache.kafka.streams.KafkaStreams.lambda$setUncaughtExceptionHandler$1(KafkaStreams.java:427)
> at
> org.apache.kafka.streams.processor.internals.StreamThread.runLoop(StreamThread.java:607)
> at
> org.apache.kafka.streams.processor.internals.StreamThread.run(StreamThread.java:555)
> {code}
>
> followed by:
> {code:java}
> Exception in thread "i-0e4d869ffd67ec825-StreamThread-1"
> java.util.ConcurrentModificationException: KafkaConsumer is not safe for
> multi-threaded access at
> org.apache.kafka.clients.consumer.KafkaConsumer.acquire(KafkaConsumer.java:2446)
> at
> org.apache.kafka.clients.consumer.KafkaConsumer.acquireAndEnsureOpen(KafkaConsumer.java:2430)
> at
> org.apache.kafka.clients.consumer.KafkaConsumer.enforceRebalance(KafkaConsumer.java:2261)
> at
> org.apache.kafka.streams.processor.internals.StreamThread.sendShutdownRequest(StreamThread.java:666)
> at
> org.apache.kafka.streams.KafkaStreams.lambda$handleStreamsUncaughtException$4(KafkaStreams.java:508)
> at
> org.apache.kafka.streams.KafkaStreams.processStreamThread(KafkaStreams.java:1579)
> at
> org.apache.kafka.streams.KafkaStreams.handleStreamsUncaughtException(KafkaStreams.java:508)
> at
> org.apache.kafka.streams.KafkaStreams.lambda$setUncaughtExceptionHandler$1(KafkaStreams.java:427)
> at
> org.apache.kafka.streams.processor.internals.StreamThread.runLoop(StreamThread.java:607)
> at
> org.apache.kafka.streams.processor.internals.StreamThread.run(StreamThread.java:555)
> {code}
> My understanding so far is that we re-use the consumer name across thread
> generations which can hit a few flavours of a race condition. My suggestion
> would be to add the generation-id to the consumer name.
> This could be done by adding a thread generation id here
> https://github.com/apache/kafka/blob/b35ca4349dabb199411cb6bc4c80ef89f19d9328/streams/src/main/java/org/apache/kafka/streams/processor/internals/ClientUtils.java#L66
> or by adding an overload here:
> https://github.com/apache/kafka/blob/b35ca4349dabb199411cb6bc4c80ef89f19d9328/streams/src/main/java/org/apache/kafka/streams/processor/internals/StreamThread.java#L390
> {code:java}
> // Some comments here
> final Map<String, Object> consumerConfigs =
> config.getMainConsumerConfigs(applicationId, getConsumerClientId(threadId),
> threadIdx, generationId);
> {code}
> I have not yet checked if there are any implications to either of these
> solutions
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