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https://issues.apache.org/jira/browse/HDFS-4461?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13568320#comment-13568320
 ] 

Hadoop QA commented on HDFS-4461:
---------------------------------

{color:red}-1 overall{color}.  Here are the results of testing the latest 
attachment 
  http://issues.apache.org/jira/secure/attachment/12567472/memory-analysis.png
  against trunk revision .

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

Console output: https://builds.apache.org/job/PreCommit-HDFS-Build/3927//console

This message is automatically generated.
                
> DirectoryScanner: volume path prefix takes up memory for every block that is 
> scanned 
> -------------------------------------------------------------------------------------
>
>                 Key: HDFS-4461
>                 URL: https://issues.apache.org/jira/browse/HDFS-4461
>             Project: Hadoop HDFS
>          Issue Type: Improvement
>    Affects Versions: 2.0.3-alpha
>            Reporter: Colin Patrick McCabe
>            Assignee: Colin Patrick McCabe
>            Priority: Minor
>         Attachments: 002.patch, memory-analysis.png
>
>
> In the {{DirectoryScanner}}, we create a class {{ScanInfo}} for every block.  
> This object contains two File objects-- one for the metadata file, and one 
> for the block file.  Since those File objects contain full paths, users who 
> pick a lengthly path for their volume roots will end up using an extra 
> N_blocks * path_prefix bytes per block scanned.  We also don't really need to 
> store File objects-- storing strings and then creating File objects as needed 
> would be cheaper.  This has been causing out-of-memory conditions for users 
> who pick such long volume paths.

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