hadoop-hdfs-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Suresh Srinivas (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HDFS-1110) Namenode heap optimization - reuse objects for commonly used file names
Date Fri, 30 Apr 2010 20:08:56 GMT

    [ https://issues.apache.org/jira/browse/HDFS-1110?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12862842#action_12862842
] 

Suresh Srinivas commented on HDFS-1110:
---------------------------------------

Access to the map is only during write operations (create and while digesting editslog). All
of that is synchronized by a large FSNamesystem lock. Also I am not proposing to do reference
counting. Once in this map, it will remain there. The map it self should not have large number
of entries, only the top N popular names.

> Namenode heap optimization - reuse objects for commonly used file names
> -----------------------------------------------------------------------
>
>                 Key: HDFS-1110
>                 URL: https://issues.apache.org/jira/browse/HDFS-1110
>             Project: Hadoop HDFS
>          Issue Type: Improvement
>            Reporter: Suresh Srinivas
>            Assignee: Suresh Srinivas
>             Fix For: 0.22.0
>
>         Attachments: hdfs-1110.2.patch, hdfs-1110.patch
>
>
> There are a lot of common file names used in HDFS, mainly created by mapreduce, such
as file names starting with "part". Reusing byte[] corresponding to these recurring file names
will save significant heap space used for storing the file names in millions of INodeFile
objects.

-- 
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