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https://issues.apache.org/jira/browse/HADOOP-4998?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12662930#action_12662930
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Steve Loughran commented on HADOOP-4998:
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It's worth remembering that once you go to JNI, you are more at risk from
memory leaks, pointer problems, race conditions and other C/C++ coding issues
that can affect long-lived programs. The benchmarks would also need to track
process memory consumption to make sure that switching to a JNI wrapper didn't
cause the memory use of the app to grow, and it would be handy to have an
option in production systems to switch from JNI to shell calls to see if it
makes any observed problems go away.
This isn't a -1 to a JNI, just a warning that there can often be a price.
Incidentally, in past experiments of mine, a JNI call takes about 600 PII clock
cycles cycles round trip; this is a lot less than starting a process, but not
entirely free.
> Implement a native OS runtime for Hadoop
> ----------------------------------------
>
> Key: HADOOP-4998
> URL: https://issues.apache.org/jira/browse/HADOOP-4998
> Project: Hadoop Core
> Issue Type: New Feature
> Components: native
> Reporter: Arun C Murthy
> Assignee: Arun C Murthy
> Fix For: 0.21.0
>
>
> It would be useful to implement a JNI-based runtime for Hadoop to get access
> to the native OS runtime. This would allow us to stop relying on exec'ing
> bash to get access to information such as user-groups, process limits etc.
> and for features such as chown/chgrp (org.apache.hadoop.util.Shell).
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