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