[jira] Updated: (HADOOP-4339) Improve FsShell -du/-dus and FileSystem.getContentSummary efficiency

["David Phillips (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/HADOOP-4339?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

David Phillips updated HADOOP-4339:
-----------------------------------

    Attachment: simple.patch

Patch for the simple solution.  This reduces calls to getFileStatus to one per directory for -du and -dus [1], as opposed to the previous one (-dus) or two (-dus) per file and directory.

[1] -dus still has an extra call for the base directory due to the initial call to globStatus.

> Improve FsShell -du/-dus and FileSystem.getContentSummary efficiency
> --------------------------------------------------------------------
>
>                 Key: HADOOP-4339
>                 URL: https://issues.apache.org/jira/browse/HADOOP-4339
>             Project: Hadoop Core
>          Issue Type: Bug
>          Components: fs
>    Affects Versions: 0.18.1
>            Reporter: David Phillips
>         Attachments: simple.patch
>
>
> FsShell.du has two inefficiencies:
> * calling getContentSummary twice for each top-level item rather than calling it once and saving the result
> * calling getContentSummary for files rather than using the size it already has in FileStatus
> getContentSummary has one:
> * calling itself for files rather than using the length it already has in FileStatus
> Every call to getContentSummary results in a call to getFileStatus, which may be expensive (e.g. NativeS3FileSystem has both network latency and actual monetary cost).
> The simple solution:
> * FsShell.du calls once per item and saves the ContentSummary
> * FsShell.du uses FileStatus.getLen for files
> * getContentSummary only calls itself for directories
> Another solution, rather than adding special casing to callers, is to add a getContentSummary that takes a FileStatus.

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