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https://issues.apache.org/jira/browse/HADOOP-12707?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Chris Nauroth resolved HADOOP-12707.
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Resolution: Won't Fix
Hello, [~haitao-tony]. Thank you for filing the issue, but the current
implementation of {{UserGroupInformation#hashCode}} and
{{UserGroupInformation#equals}} is by design. Please see issue HADOOP-6670 if
you're interested in more background.
I have 2 suggestions to offer for the memory leak problem that you noticed:
# Consider using the {{FileSystem#closeAllForUGI}} method, which would close
all cached instances for a user.
# If it's not possible to change code, then consider disabling the cache by
setting configuration property {{fs.hdfs.impl.disable.cache}} to {{true}} in
core-site.xml. This would bypass the cache completely, which might be
appropriate depending on your application.
> key of FileSystem inner class Cache contains UGI.hascode which uses the
> defualt hascode method, leading to the memory leak
> --------------------------------------------------------------------------------------------------------------------------
>
> Key: HADOOP-12707
> URL: https://issues.apache.org/jira/browse/HADOOP-12707
> Project: Hadoop Common
> Issue Type: Bug
> Components: fs
> Affects Versions: 2.7.1
> Reporter: sunhaitao
> Assignee: sunhaitao
>
> FileSystem.get(conf) method,By default it will get the fs object from
> CACHE,But the key of the CACHE constains ugi.hashCode, which uses the
> default hascode method of subject instead of the hascode method overwritten
> by subject.
> @Override
> public int hashCode() {
> return (scheme + authority).hashCode() + ugi.hashCode() + (int)unique;
> }
> In this case, even if same user, if the calll FileSystem.get(conf) twice, two
> different key will be created. In long duartion, this will lead to memory
> leak.
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