[jira] [Commented] (HIVE-17020) Aggressive RS dedup can incorrectly remove OP tree branch

["Rui Li (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HIVE-17020?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16073617#comment-16073617 ] 

Rui Li commented on HIVE-17020:
-------------------------------

I think we can disable aggressive dedup if any parent of RS5 has more than one child, and leave it to the normal case.

> Aggressive RS dedup can incorrectly remove OP tree branch
> ---------------------------------------------------------
>
>                 Key: HIVE-17020
>                 URL: https://issues.apache.org/jira/browse/HIVE-17020
>             Project: Hive
>          Issue Type: Bug
>            Reporter: Rui Li
>            Assignee: Rui Li
>
> Suppose we have an OP tree like this:
> {noformat}
>      ...
>       |
>      RS[1]
>       |
>     SEL[2]
>     /    \
> SEL[3]   SEL[4]
>   |         |
> RS[5]     FS[6]
>   |
>  ... 
> {noformat}
> When doing aggressive RS dedup, we'll remove all the operators between RS5 and RS1, and thus the branch containing FS6 is lost.



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