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From "Rohini Palaniswamy (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (PIG-4662) New optimizer rule: filter nulls before inner joins
Date Wed, 24 May 2017 22:53:04 GMT

    [ https://issues.apache.org/jira/browse/PIG-4662?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16023848#comment-16023848
] 

Rohini Palaniswamy commented on PIG-4662:
-----------------------------------------

Have already done this in POBuildBloomRearrangeTez. You can refer that.

> New optimizer rule: filter nulls before inner joins
> ---------------------------------------------------
>
>                 Key: PIG-4662
>                 URL: https://issues.apache.org/jira/browse/PIG-4662
>             Project: Pig
>          Issue Type: Improvement
>            Reporter: Ido Hadanny
>            Assignee: Satish Subhashrao Saley
>            Priority: Minor
>              Labels: Performance
>             Fix For: 0.17.0
>
>
> As stated in the docs, rewriting an inner join and filtering nulls from inputs can be
a big performance gain: http://pig.apache.org/docs/r0.14.0/perf.html#nulls
> We would like to add an optimizer rule which detects inner joins, and filters nulls in
all inputs:
> A = filter A by t is not null;
> B = filter B by x is not null;
> C = join A by t, B by x;
> see also: http://stackoverflow.com/questions/32088389/is-the-pig-optimizer-filtering-nulls-before-joining



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