[jira] [Updated] (PIG-4662) New optimizer rule: filter nulls before inner joins

["Rohini Palaniswamy (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/PIG-4662?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Rohini Palaniswamy updated PIG-4662:
------------------------------------
    Fix Version/s: 0.17.0

  Instead of an optimizer, this can probably be tagged on to POLocalRearrange to skip null keys.

> 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
>            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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