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From "Tsz Wo (Nicholas), SZE (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HADOOP-6467) Performance improvement for liststatus on directories in hadoop archives.
Date Mon, 22 Feb 2010 18:48:28 GMT

    [ https://issues.apache.org/jira/browse/HADOOP-6467?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12836821#action_12836821
] 

Tsz Wo (Nicholas), SZE commented on HADOOP-6467:
------------------------------------------------

- Should we have a try-finally on aIn/aLin to close the file?  Otherwise, the file will remain
open in case of an IOException.

- The codes below are expensive since only parsed[0] is needed.  We could avoid regular expression
by lineFeed.indexOf(" ") in finding parsed[0].
{code}
+        String[] parsed = lineFeed.split(" ");
+        Path thisPath = new Path(parsed[0]);
+        if ((parsed[0].startsWith(parentString)) && (thisPath.depth() == harPath.depth()
+ 1)) {
{code}

- BTW, what if there is a " " in a path?  Would har work??  If not, we should fix it or document
it.

> Performance improvement for liststatus on directories in hadoop archives.
> -------------------------------------------------------------------------
>
>                 Key: HADOOP-6467
>                 URL: https://issues.apache.org/jira/browse/HADOOP-6467
>             Project: Hadoop Common
>          Issue Type: Improvement
>            Reporter: Mahadev konar
>            Assignee: Mahadev konar
>             Fix For: 0.22.0
>
>         Attachments: Archives_performance.docx, Archives_performance.docx, HADOOP-6467-y0.20-branch.patch,
HADOOP-6467.patch, HADOOP-6467.patch, HADOOP-6467.patch
>
>
> A liststatus call on a directory in hadoop archives leads to ( 2* number of files in
directory) open calls to the namenode. This is very sub optimal and needs to be fixed to make
it performant enough to be used on a daily basis. 

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