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Date: Tue, 14 Oct 2008 15:03:44 -0700 (PDT)
From: "Raghu Angadi (JIRA)" <jira@apache.org>
To: core-dev@hadoop.apache.org
Subject: [jira] Commented: (HADOOP-4412) hadoop dfs -find feature
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    [ https://issues.apache.org/jira/browse/HADOOP-4412?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12639616#action_12639616 ] 

Raghu Angadi commented on HADOOP-4412:
--------------------------------------

Regd 'dfs -rm', another option could be to give an option to use a thread pool at the client. This will be client-only fix and can easily increase the removal rate by 5-10 times (using 10-20 threads).. this code could be common for many commands.

> hadoop dfs -find feature
> ------------------------
>
>                 Key: HADOOP-4412
>                 URL: https://issues.apache.org/jira/browse/HADOOP-4412
>             Project: Hadoop Core
>          Issue Type: New Feature
>          Components: dfs
>            Reporter: Marco Nicosia
>
> Both sysadmins and users make frequent use of the unix 'find' command, but Hadoop has no correlate. Without this, users are writing scripts which make heavy use of hadoop dfs -lsr, and implementing find one-offs. I think hdfs -lsr is somewhat taxing on the NameNode, and a really slow experience on the client side. Possibly an in-NameNode find operation would be only a bit more taxing on the NameNode, but significantly faster from the client's point of view?
> The minimum set of options I can think of which would make a Hadoop find command generally useful is (in priority order):
> * -type (file or directory, for now)
> * -atime/-ctime-mtime (... and -creationtime?) (both + and - arguments)
> * -print0 (for piping to xargs -0)
> * -depth
> * -owner/-group (and -nouser/-nogroup)
> * -name (allowing for shell pattern, or even regex?)
> * -perm
> * -size
> One possible special case, but could possibly be really cool if it ran from within the NameNode:
> * -delete
> The "hadoop dfs -lsr | hadoop dfs -rm" cycle is really, really slow.
> Lower priority, some people do use operators, mostly to execute -or searches such as:
> * find / \(-nouser -or -nogroup\)
> Finally, I thought I'd include a link to the [Posix spec for find|http://www.opengroup.org/onlinepubs/009695399/utilities/find.html]

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