hadoop-common-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Sameer Paranjpye (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HADOOP-713) dfs list operation is too expensive
Date Wed, 14 Nov 2007 23:17:43 GMT

    [ https://issues.apache.org/jira/browse/HADOOP-713?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12542628
] 

Sameer Paranjpye commented on HADOOP-713:
-----------------------------------------

> If not, we could bump the protocol version, which we normally try to avoid in a point
release, but I think it might be better to fail than to give the wrong answer.

If we're bumping the protocol version, we may as well add the new call.

> dfs list operation is too expensive
> -----------------------------------
>
>                 Key: HADOOP-713
>                 URL: https://issues.apache.org/jira/browse/HADOOP-713
>             Project: Hadoop
>          Issue Type: Improvement
>          Components: dfs
>    Affects Versions: 0.8.0
>            Reporter: Hairong Kuang
>            Assignee: dhruba borthakur
>            Priority: Blocker
>             Fix For: 0.15.1
>
>         Attachments: optimizeComputeContentLen.patch
>
>
> A list request to dfs returns an array of DFSFileInfo. A DFSFileInfo of a directory contains
a field called contentsLen, indicating its size  which gets computed at the namenode side
by resursively going through its subdirs. At the same time, the whole dfs directory tree is
locked.
> The list operation is used a lot by DFSClient for listing a directory, getting a file's
size and # of replicas, and getting the size of dfs. Only the last operation needs the field
contentsLen to be computed.
> To reduce its cost, we can add a flag to the list request. ContentsLen is computed If
the flag is set. By default, the flag is false.

-- 
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.


Mime
View raw message