[jira] [Commented] (PIG-4587) Only apply isFirstReduceOfKey for Skewed right outer join

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

    [ https://issues.apache.org/jira/browse/PIG-4587?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15105548#comment-15105548 ] 

Rohini Palaniswamy commented on PIG-4587:
-----------------------------------------

Found that PIG-4377 fix for right outer join produces wrong results with left outer join and skips records if it is not the first reducer which is very bad.

> Only apply isFirstReduceOfKey for Skewed right outer join
> ---------------------------------------------------------
>
>                 Key: PIG-4587
>                 URL: https://issues.apache.org/jira/browse/PIG-4587
>             Project: Pig
>          Issue Type: Bug
>            Reporter: Rohini Palaniswamy
>            Assignee: Daniel Dai
>             Fix For: 0.16.0
>
>
> PIG-4377 introduced isFirstReduceOfKey to avoid extra records in case of over sampling. But the issue can occur only in the case of right outer join. But it is added to the plan in MRCompiler and TezCompiler (PIG-4580) for both left and right outer joins. We need to remove that extra check for right outer join. It is unnecessary performance penalty.



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