[jira] [Commented] (MAPREDUCE-4907) TrackerDistributedCacheManager issues too many getFileStatus calls

["Hadoop QA (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/MAPREDUCE-4907?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13540681#comment-13540681 ] 

Hadoop QA commented on MAPREDUCE-4907:
--------------------------------------

{color:red}-1 overall{color}.  Here are the results of testing the latest attachment 
  http://issues.apache.org/jira/secure/attachment/12562625/MAPREDUCE-4907.patch
  against trunk revision .

    {color:red}-1 patch{color}.  The patch command could not apply the patch.

Console output: https://builds.apache.org/job/PreCommit-MAPREDUCE-Build/3182//console

This message is automatically generated.
                
> TrackerDistributedCacheManager issues too many getFileStatus calls
> ------------------------------------------------------------------
>
>                 Key: MAPREDUCE-4907
>                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-4907
>             Project: Hadoop Map/Reduce
>          Issue Type: Bug
>          Components: mrv1, tasktracker
>    Affects Versions: 1.1.1
>            Reporter: Sandy Ryza
>            Assignee: Sandy Ryza
>         Attachments: MAPREDUCE-4907.patch
>
>
> TrackerDistributedCacheManager issues a number of redundant getFileStatus calls when determining the timestamps and visibilities of files in the distributed cache.  300 distributed cache files deep in the directory structure can hammer HDFS with a couple thousand requests.
> A couple optimizations can reduce this load:
> 1. determineTimestamps and determineCacheVisibilities both call getFileStatus on every file.  We could cache the results of the former and use them for the latter.
> 2. determineCacheVisibilities needs to check that all ancestor directories of each file have execute permissions for everyone.  This currently entails a getFileStatus on each ancestor directory for each file.  The results of these getFileStatus calls could be cached as well.

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