You are viewing a plain text version of this content. The canonical link for it is here.

Posted to common-dev@hadoop.apache.org by "Owen O'Malley (JIRA)" <ji...@apache.org> on 2008/02/14 22:05:09 UTC

[jira] Updated: (HADOOP-2399) Input key and value to combiner and reducer should be reused

     [ https://issues.apache.org/jira/browse/HADOOP-2399?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Owen O'Malley updated HADOOP-2399:
----------------------------------

    Attachment: reuse-obj-2.patch

This patch changes the ValueIterator to have 2 instances of the key, and 1 instance of the object and reuse the objects during the iteration. I also fixed some of the compiler warnings for unbound generic types in the ValueIterator.

> Input key and value to combiner and reducer should be reused
> ------------------------------------------------------------
>
>                 Key: HADOOP-2399
>                 URL: https://issues.apache.org/jira/browse/HADOOP-2399
>             Project: Hadoop Core
>          Issue Type: Bug
>          Components: mapred
>    Affects Versions: 0.15.1
>            Reporter: Owen O'Malley
>            Assignee: Owen O'Malley
>         Attachments: reuse-obj-2.patch, reuse-obj.patch
>
>
> Currently, the input key and value are recreated on every iteration for input to the combiner and reducer. It would speed up the system substantially if we reused the keys and values. The down side of doing it, is that it may break applications that count on holding references to previous keys and values, but I think it is worth doing.

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