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 "Chris Douglas (JIRA)" <ji...@apache.org> on 2008/06/03 06:40:44 UTC

[jira] Updated: (HADOOP-3443) map outputs should not be renamed between partitions

     [ https://issues.apache.org/jira/browse/HADOOP-3443?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Chris Douglas updated HADOOP-3443:
----------------------------------

    Attachment: hadoop-3443-1v17.patch

Port to 0.17, if we need it.

> map outputs should not be renamed between partitions
> ----------------------------------------------------
>
>                 Key: HADOOP-3443
>                 URL: https://issues.apache.org/jira/browse/HADOOP-3443
>             Project: Hadoop Core
>          Issue Type: Bug
>          Components: mapred
>    Affects Versions: 0.17.0
>            Reporter: Owen O'Malley
>            Assignee: Owen O'Malley
>            Priority: Critical
>             Fix For: 0.18.0
>
>         Attachments: hadoop-3443-1.patch, hadoop-3443-1v17.patch
>
>
> If a map finishes with out having to spill its data buffer, the map outputs are sorted and written to disk. However, no care is taken to make sure that the same partition is used to write it out before it is renamed. On nodes with multiple disks assigned to the task trackers, this will likely cause an addition read/write cycle to disk that is very expensive.

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