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From "Ashutosh Chauhan (JIRA)" <j...@apache.org>
Subject [jira] Commented: (PIG-865) Performance: Unnnecessary computation in FRJoin
Date Mon, 29 Jun 2009 22:06:47 GMT

    [ https://issues.apache.org/jira/browse/PIG-865?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12725368#action_12725368
] 

Ashutosh Chauhan commented on PIG-865:
--------------------------------------

Thanks for the review, Pradeep. 
As I was looking into code, I also found that bags used to hold replicate contents are recreated
everytime, instead same bag object can be cleared and used again, thus minimizing object overhead.
In the extreme case where every value of join key is different for every tuple (of replicate)
but matches with tuples of fragment, we will end up creating as many bags as there are tuples
where one bag would do. Will include this change and upload new patch.

   

> Performance: Unnnecessary computation in FRJoin
> -----------------------------------------------
>
>                 Key: PIG-865
>                 URL: https://issues.apache.org/jira/browse/PIG-865
>             Project: Pig
>          Issue Type: Improvement
>          Components: impl
>    Affects Versions: 0.3.0
>            Reporter: Ashutosh Chauhan
>            Priority: Minor
>             Fix For: 0.4.0
>
>         Attachments: pig-865.patch
>
>
> In POFRJoin implementation POLocalRearrange is used to extract join keys from the input
tuples. If keys match then to perform actual join input tuples are fed to Foreach which does
a cross on its inputs. After keys are extracted using POLocalRearrange output; function getValueTuple(POLocalRearrange
lr, Tuple tuple) is called to reconstruct the input tuple. It seems that this function call
is unnecessary since we already have input tuple at that time. 
> This is not a bug, but since this function would get called for every tuple, if it is
eliminated, it should certainly help to improve performance. 

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