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 2008/06/18 00:42:45 UTC

[jira] Updated: (HADOOP-3586) keep combiner backward compatible with earlier versions of hadoop

     [ https://issues.apache.org/jira/browse/HADOOP-3586?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Chris Douglas updated HADOOP-3586:
----------------------------------

    Priority: Blocker  (was: Major)

> keep combiner backward compatible with earlier versions of hadoop
> -----------------------------------------------------------------
>
>                 Key: HADOOP-3586
>                 URL: https://issues.apache.org/jira/browse/HADOOP-3586
>             Project: Hadoop Core
>          Issue Type: Bug
>            Reporter: Olga Natkovich
>            Assignee: Chris Douglas
>            Priority: Blocker
>             Fix For: 0.18.0
>
>
> In hadoop 16 and earlier, the combiner was guaranteed to run once and only once for each map. In 17 this compatibility was slightly broken: the combiner does not run if a single <K,V> occupies the entire sort buffer. In 18, this is further changed to where the combiner can be called multiple times on both map and reduce sides.
> This breaks Pig's current implementation of the combiner and it is not easy to fix in a short period of time.
> We would like to ask that for a way for an application to ask for a backward compatible behavior for some period of time until it can adjust to the new behavior.

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