[jira] Resolved: (PIG-1530) PIG Logical Optimization: Push LOFilter above LOCogroup

["Olga Natkovich (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/PIG-1530?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Olga Natkovich resolved PIG-1530.
---------------------------------

    Resolution: Duplicate

Xuefu is addressing this issue as part of https://issues.apache.org/jira/browse/PIG-1575.

>  PIG Logical Optimization: Push LOFilter above LOCogroup
> --------------------------------------------------------
>
>                 Key: PIG-1530
>                 URL: https://issues.apache.org/jira/browse/PIG-1530
>             Project: Pig
>          Issue Type: New Feature
>          Components: impl
>            Reporter: Swati Jain
>            Assignee: Swati Jain
>            Priority: Minor
>             Fix For: 0.8.0
>
>
> Consider the following:
> {noformat}
> A = load '<any file>' USING PigStorage(',') as (a1:int,a2:int,a3:int);
> B = load '<any file>' USING PigStorage(',') as (b1:int,b2:int,b3:int);
> G = COGROUP A by (a1,a2) , B by (b1,b2);
> D = Filter G by group.$0 + 5 > group.$1;
> explain D;
> {noformat}
> In the above example, LOFilter can be pushed above LOCogroup. Note there are some tricky NULL issues to think about when the Cogroup is not of type INNER (Similar to issues that need to be thought through when pushing LOFilter on the right side of a LeftOuterJoin).
> Also note that typically the LOFilter in user programs will be below a ForEach-Cogroup pair. To make this really useful, we need to also implement LOFilter pushed across ForEach. 

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