[jira] [Assigned] (HIVE-8518) Compile time skew join optimization returns duplicated results

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

     [ https://issues.apache.org/jira/browse/HIVE-8518?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Rui Li reassigned HIVE-8518:
----------------------------

    Assignee: Rui Li

> Compile time skew join optimization returns duplicated results
> --------------------------------------------------------------
>
>                 Key: HIVE-8518
>                 URL: https://issues.apache.org/jira/browse/HIVE-8518
>             Project: Hive
>          Issue Type: Bug
>            Reporter: Rui Li
>            Assignee: Rui Li
>
> Compile time skew join optimization clones the join operator tree and unions the results.
> The problem here is that we don't properly insert the predicate for the cloned join (relying on an assert statement).
> To reproduce the issue, run the simple query:
> {code}select * from tbl1 join tbl2 on tbl1.key=tbl2.key;{code}
> And suppose there's some skew in tbl1 (specify skew with CREATE or ALTER statement).
> Duplicated results will be returned if you set hive.optimize.skewjoin.compiletime=true.



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