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From "Chris Douglas (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (YARN-1771) many getFileStatus calls made from node manager for localizing a public distributed cache resource
Date Wed, 12 Mar 2014 23:31:47 GMT

    [ https://issues.apache.org/jira/browse/YARN-1771?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13932651#comment-13932651
] 

Chris Douglas commented on YARN-1771:
-------------------------------------

bq. I'm also going to make changes to memoize failures. The only slight hesitation I have
is normally that would be quite rare, but I think it's a good thing to have.

Agreed, I doubt it will have a significant impact, here. In a shared/longer-lived cache it
might be marginally more useful, but still rare.

bq. I did think about making the stat cache longer-lived. But the complexity of managing its
size as well as the values getting quite stale dissuaded me from it. Let me know if you agree...

*nod* Since the goal is to reduce stress on the NN, deferring that complexity until necessary
is a good plan.

> many getFileStatus calls made from node manager for localizing a public distributed cache
resource
> --------------------------------------------------------------------------------------------------
>
>                 Key: YARN-1771
>                 URL: https://issues.apache.org/jira/browse/YARN-1771
>             Project: Hadoop YARN
>          Issue Type: Bug
>          Components: nodemanager
>    Affects Versions: 2.3.0
>            Reporter: Sangjin Lee
>            Assignee: Sangjin Lee
>            Priority: Critical
>         Attachments: yarn-1771.patch, yarn-1771.patch, yarn-1771.patch
>
>
> We're observing that the getFileStatus calls are putting a fair amount of load on the
name node as part of checking the public-ness for localizing a resource that belong in the
public cache.
> We see 7 getFileStatus calls made for each of these resource. We should look into reducing
the number of calls to the name node. One example:
> {noformat}
> 2014-02-27 18:07:27,351 INFO audit: ... cmd=getfileinfo	src=/tmp/temp-887708724/tmp883330348/foo-0.0.44.jar
...
> 2014-02-27 18:07:27,352 INFO audit: ... cmd=getfileinfo	src=/tmp/temp-887708724/tmp883330348/foo-0.0.44.jar
...
> 2014-02-27 18:07:27,352 INFO audit: ... cmd=getfileinfo	src=/tmp/temp-887708724/tmp883330348
...
> 2014-02-27 18:07:27,353 INFO audit: ... cmd=getfileinfo	src=/tmp/temp-887708724 ...
> 2014-02-27 18:07:27,353 INFO audit: ... cmd=getfileinfo	src=/tmp ...
> 2014-02-27 18:07:27,354 INFO audit: ... cmd=getfileinfo	src=/	 ...
> 2014-02-27 18:07:27,354 INFO audit: ... cmd=getfileinfo	src=/tmp/temp-887708724/tmp883330348/foo-0.0.44.jar
...
> 2014-02-27 18:07:27,355 INFO audit: ... cmd=open	src=/tmp/temp-887708724/tmp883330348/foo-0.0.44.jar
...
> {noformat}



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