[ https://issues.apache.org/jira/browse/FLINK-10774?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16687465#comment-16687465 ]
ASF GitHub Bot commented on FLINK-10774: ---------------------------------------- stevenzwu commented on issue #7020: [FLINK-10774] [Kafka] connection leak when partition discovery is disabled an… URL: https://github.com/apache/flink/pull/7020#issuecomment-438914628 Got the evidence that it is thread safety problem ``` 2018-11-15 04:24:17,795 ERROR org.apache.flink.streaming.connectors.kafka.FlinkKafkaConsumerBase - failed to close partitionDiscoverer java.util.ConcurrentModificationException: KafkaConsumer is not safe for multi-threaded access at org.apache.kafka.clients.consumer.KafkaConsumer.acquire(KafkaConsumer.java:1627) at org.apache.kafka.clients.consumer.KafkaConsumer.close(KafkaConsumer.java:1526) at org.apache.kafka.clients.consumer.KafkaConsumer.close(KafkaConsumer.java:1506) at org.apache.flink.streaming.connectors.kafka.internal.Kafka09PartitionDiscoverer.closeConnections(Kafka09PartitionDiscoverer.java:97) at org.apache.flink.streaming.connectors.kafka.internals.AbstractPartitionDiscoverer.close(AbstractPartitionDiscoverer.java:101) at org.apache.flink.streaming.connectors.kafka.FlinkKafkaConsumerBase.cancel(FlinkKafkaConsumerBase.java:673) at org.apache.flink.streaming.api.operators.StreamSource.cancel(StreamSource.java:108) at org.apache.flink.streaming.runtime.tasks.SourceStreamTask.cancelTask(SourceStreamTask.java:100) at org.apache.flink.streaming.runtime.tasks.StreamTask.cancel(StreamTask.java:369) at org.apache.flink.runtime.taskmanager.Task$TaskCanceler.run(Task.java:1481) at java.lang.Thread.run(Thread.java:748) ``` ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org > connection leak when partition discovery is disabled and open throws exception > ------------------------------------------------------------------------------ > > Key: FLINK-10774 > URL: https://issues.apache.org/jira/browse/FLINK-10774 > Project: Flink > Issue Type: Bug > Components: Kafka Connector > Affects Versions: 1.4.2, 1.5.5, 1.6.2 > Reporter: Steven Zhen Wu > Assignee: Steven Zhen Wu > Priority: Major > Labels: pull-request-available > > Here is the scenario to reproduce the issue > * partition discovery is disabled > * open method throws an exception (e.g. when broker SSL authorization denies > request) > In this scenario, run method won't be executed. As a result, > _partitionDiscoverer.close()_ won't be called. that caused the connection > leak, because KafkaConsumer is initialized but not closed. That has caused > outage that brought down our Kafka cluster, when a high-parallelism job got > into a restart/failure loop. -- This message was sent by Atlassian JIRA (v7.6.3#76005)