Mailing-List: contact hdfs-issues-help@hadoop.apache.org; run by ezmlm
Precedence: bulk
Reply-To: hdfs-issues@hadoop.apache.org
Date: Fri, 12 Aug 2011 06:42:27 +0000 (UTC)
From: "Tsz Wo (Nicholas), SZE (JIRA)" <jira@apache.org>
To: hdfs-issues@hadoop.apache.org
Message-ID: 
 <1926297508.32530.1313131347604.JavaMail.tomcat@hel.zones.apache.org>
Subject: [jira] [Commented] (HDFS-362) FSEditLog should not writes long and
 short as UTF8 and should not use ArrayWritable for writing non-array items
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit


    [ https://issues.apache.org/jira/browse/HDFS-362?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13083979#comment-13083979 ] 

Tsz Wo (Nicholas), SZE commented on HDFS-362:
---------------------------------------------

Hi Uma, we have to update LAYOUT_VERSION and support reading on files with older versions.  See HDFS-1630 as an example.

> FSEditLog should not writes long and short as UTF8 and should not use ArrayWritable for writing non-array items
> ---------------------------------------------------------------------------------------------------------------
>
>                 Key: HDFS-362
>                 URL: https://issues.apache.org/jira/browse/HDFS-362
>             Project: Hadoop HDFS
>          Issue Type: Improvement
>          Components: name-node
>            Reporter: Tsz Wo (Nicholas), SZE
>            Assignee: Uma Maheswara Rao G
>         Attachments: HDFS-362.1.patch, HDFS-362.patch
>
>
> In FSEditLog, 
> - long and short are first converted to String and are further converted to UTF8
> - For some non-array items, it first create an ArrayWritable object to hold all the items and then writes the ArrayWritable object.
> These result creating many intermediate objects which affects Namenode CPU performance and Namenode restart.

--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira