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From "Josh Wills (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (CRUNCH-23) PCollection#sort doesn't do a full sort on values
Date Mon, 06 Aug 2012 03:21:02 GMT

    [ https://issues.apache.org/jira/browse/CRUNCH-23?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13428965#comment-13428965
] 

Josh Wills commented on CRUNCH-23:
----------------------------------

Hey Rahul, two thoughts:

1) Do you have a testing strategy in mind to verify that this really works?
2) Is there a way we can move the MRPipeline-specific logic into the MRPipeline class and
have the o.a.crunch.lib.Sort stuff do all of the work via calls to methods on the Pipeline
interface?
                
> PCollection#sort doesn't do a full sort on values
> -------------------------------------------------
>
>                 Key: CRUNCH-23
>                 URL: https://issues.apache.org/jira/browse/CRUNCH-23
>             Project: Crunch
>          Issue Type: Bug
>            Reporter: Gabriel Reid
>            Assignee: Rahul Sharma
>         Attachments: 0001-CRUNCH-23-fix-sorting.patch, CRUNCH-23-used-TotalOrderpartioner-for-sorting-keys.patch,
SortTest.java
>
>
> When a PCollection is sorted (using PCollection#sort), the sorting that is performed
is only per reducer, and not an absolute sort over all values. This means that the values
are not in sorted order if they are iterated over on a materialized collection. It also means
that the sorted files that are output from a sort operation can not be simply concatenated
to come to a single sorted file.

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