[jira] [Updated] (SPARK-23756) [Performance] Redundant join elimination

["Dongjoon Hyun (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/SPARK-23756?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Dongjoon Hyun updated SPARK-23756:
----------------------------------
    Affects Version/s:     (was: 3.0.0)
                       3.1.0

> [Performance] Redundant join elimination
> ----------------------------------------
>
>                 Key: SPARK-23756
>                 URL: https://issues.apache.org/jira/browse/SPARK-23756
>             Project: Spark
>          Issue Type: Sub-task
>          Components: SQL
>    Affects Versions: 3.1.0
>            Reporter: Ioana Delaney
>            Priority: Major
>
> This rewrite eliminates self-joins on unique keys. Self-joins may be introduced after view expansion. 
> *User view:*
> {code}
> create view manager(mgrno, income) as 
> select e.empno, e.salary + e.bonus
> from employee e, department d
> where e.empno = d.mgrno;
> {code}
> *User query:*
> {code}
> select e.empname, e.empno
> from employee e, manager m
> where e.empno = m.mgrno and m.income > 100K
> {code}
> *Internal query after view expansion:*
> {code}
> select e.lastname, e.empno
> from employee e, employee m, department d
> where e.empno = m.empno /* PK = PK */ and e.empno = d.mgrno and 
> m.salary + m.bonus > 100K
> {code}
> *Internal query after join elimination:*
> {code}
> select e.lastname, e.empno
> from employee e, department d
> where e.empno = d.mgrno and 
> e.salary + e.bonus > 100K
> {code}



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