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https://issues.apache.org/jira/browse/FLINK-16142?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17096342#comment-17096342
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Aitozi commented on FLINK-16142:
--------------------------------
Hi，[~sewen] as you said , the class can not be released by classloader.close()
{code:java}
Closing the URL class loader closes the file handles to the jar files, but does
not release the classes.
It is important, for disk space cleanup but has no impact on class leaks, the
way I understand it.{code}
If we use blob server, when task run into failover, it will unregister and
register task. It will invoke classloader.close() and generater a new
classloader to load class from blob. This will make the metaspace bigger and
bigger, beacause the classloader close method can not really release the
classes. So does this behavior: create a new classloader to load class when
task failover, will always make the metaspace leak?
> Memory Leak causes Metaspace OOM error on repeated job submission
> -----------------------------------------------------------------
>
> Key: FLINK-16142
> URL: https://issues.apache.org/jira/browse/FLINK-16142
> Project: Flink
> Issue Type: Bug
> Components: Client / Job Submission
> Affects Versions: 1.10.0
> Reporter: Thomas Wozniakowski
> Assignee: Andrey Zagrebin
> Priority: Blocker
> Fix For: 1.10.1, 1.11.0
>
> Attachments: Leak-GC-root.png, java_pid1.hprof, java_pid1.hprof
>
>
> Hi Guys,
> We've just tried deploying 1.10.0 as it has lots of shiny stuff that fits our
> use-case exactly (RocksDB state backend running in a containerised cluster).
> Unfortunately, it seems like there is a memory leak somewhere in the job
> submission logic. We are getting this error:
> {code:java}
> 2020-02-18 10:22:10,020 INFO
> org.apache.flink.runtime.executiongraph.ExecutionGraph - OPERATOR_NAME
> switched from RUNNING to FAILED.
> java.lang.OutOfMemoryError: Metaspace
> at java.lang.ClassLoader.defineClass1(Native Method)
> at java.lang.ClassLoader.defineClass(ClassLoader.java:757)
> at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
> at java.net.URLClassLoader.defineClass(URLClassLoader.java:468)
> at java.net.URLClassLoader.access$100(URLClassLoader.java:74)
> at java.net.URLClassLoader$1.run(URLClassLoader.java:369)
> at java.net.URLClassLoader$1.run(URLClassLoader.java:363)
> at java.security.AccessController.doPrivileged(Native Method)
> at java.net.URLClassLoader.findClass(URLClassLoader.java:362)
> at java.lang.ClassLoader.loadClass(ClassLoader.java:419)
> at
> org.apache.flink.util.ChildFirstClassLoader.loadClass(ChildFirstClassLoader.java:60)
> at java.lang.ClassLoader.loadClass(ClassLoader.java:352)
> at
> org.apache.flink.kinesis.shaded.com.amazonaws.jmx.SdkMBeanRegistrySupport.registerMetricAdminMBean(SdkMBeanRegistrySupport.java:27)
> at
> org.apache.flink.kinesis.shaded.com.amazonaws.metrics.AwsSdkMetrics.registerMetricAdminMBean(AwsSdkMetrics.java:398)
> at
> org.apache.flink.kinesis.shaded.com.amazonaws.metrics.AwsSdkMetrics.<clinit>(AwsSdkMetrics.java:359)
> at
> org.apache.flink.kinesis.shaded.com.amazonaws.AmazonWebServiceClient.requestMetricCollector(AmazonWebServiceClient.java:728)
> at
> org.apache.flink.kinesis.shaded.com.amazonaws.AmazonWebServiceClient.isRMCEnabledAtClientOrSdkLevel(AmazonWebServiceClient.java:660)
> at
> org.apache.flink.kinesis.shaded.com.amazonaws.AmazonWebServiceClient.isRequestMetricsEnabled(AmazonWebServiceClient.java:652)
> at
> org.apache.flink.kinesis.shaded.com.amazonaws.AmazonWebServiceClient.createExecutionContext(AmazonWebServiceClient.java:611)
> at
> org.apache.flink.kinesis.shaded.com.amazonaws.AmazonWebServiceClient.createExecutionContext(AmazonWebServiceClient.java:606)
> at
> org.apache.flink.kinesis.shaded.com.amazonaws.services.kinesis.AmazonKinesisClient.executeListShards(AmazonKinesisClient.java:1534)
> at
> org.apache.flink.kinesis.shaded.com.amazonaws.services.kinesis.AmazonKinesisClient.listShards(AmazonKinesisClient.java:1528)
> at
> org.apache.flink.streaming.connectors.kinesis.proxy.KinesisProxy.listShards(KinesisProxy.java:439)
> at
> org.apache.flink.streaming.connectors.kinesis.proxy.KinesisProxy.getShardsOfStream(KinesisProxy.java:389)
> at
> org.apache.flink.streaming.connectors.kinesis.proxy.KinesisProxy.getShardList(KinesisProxy.java:279)
> at
> org.apache.flink.streaming.connectors.kinesis.internals.KinesisDataFetcher.discoverNewShardsToSubscribe(KinesisDataFetcher.java:686)
> at
> org.apache.flink.streaming.connectors.kinesis.FlinkKinesisConsumer.run(FlinkKinesisConsumer.java:287)
> at
> org.apache.flink.streaming.api.operators.StreamSource.run(StreamSource.java:100)
> at
> org.apache.flink.streaming.api.operators.StreamSource.run(StreamSource.java:63)
> {code}
> (The only change in the above text is the OPERATOR_NAME text where I removed
> some of the internal specifics of our system).
> This will reliably happen on a fresh cluster after submitting and cancelling
> our job 3 times.
> We are using the presto-s3 plugin, the CEP library and the Kinesis connector.
> Please let me know what other diagnostics would be useful.
> Tom
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