[jira] [Resolved] (CALCITE-2329) Enhance SubQueryRemoveRule to rewrite IN operator with the constant from the left side more optimally

["Julian Hyde (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/CALCITE-2329?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Julian Hyde resolved CALCITE-2329.
----------------------------------
       Resolution: Fixed
    Fix Version/s: 1.17.0

Fixed in [1ae6a526|http://git-wip-us.apache.org/repos/asf/calcite/commit/1ae6a526].

> Enhance SubQueryRemoveRule to rewrite IN operator with the constant from the left side more optimally
> -----------------------------------------------------------------------------------------------------
>
>                 Key: CALCITE-2329
>                 URL: https://issues.apache.org/jira/browse/CALCITE-2329
>             Project: Calcite
>          Issue Type: Improvement
>            Reporter: Volodymyr Vysotskyi
>            Assignee: Julian Hyde
>            Priority: Major
>             Fix For: 1.17.0
>
>
> Currently, for queries like this:
> {code:sql}
> select sal from emp where 2 IN (select deptno from dept)
> {code}
> SubQueryRemoveRule rules expand query plan in such a way:
> {noformat}
> LogicalProject(SAL=[$5])
>   LogicalProject(EMPNO=[$0], ENAME=[$1], JOB=[$2], MGR=[$3], HIREDATE=[$4], SAL=[$5], COMM=[$6], DEPTNO=[$7], SLACKER=[$8])
>     LogicalJoin(condition=[=(2, $9)], joinType=[inner])
>       LogicalTableScan(table=[[CATALOG, SALES, EMP]])
>       LogicalProject(DEPTNO=[$0])
>         LogicalTableScan(table=[[CATALOG, SALES, DEPT]])
> {noformat}
> Since join condition is actually a filter condition, it will be pushed into the filter during further planning stages and join with the true condition is left.
> But these types of the queries may be rewritten in the same way as EXISTS queries:
> {code:sql}
> select sal from emp where EXISTS (select deptno from dept where deptno=2)
> {code}
> with the more optimal plan:
> {noformat}
> LogicalProject(SAL=[$5])
>   LogicalProject(EMPNO=[$0], ENAME=[$1], JOB=[$2], MGR=[$3], HIREDATE=[$4], SAL=[$5], COMM=[$6], DEPTNO=[$7], SLACKER=[$8])
>     LogicalJoin(condition=[true], joinType=[inner])
>       LogicalTableScan(table=[[CATALOG, SALES, EMP]])
>       LogicalAggregate(group=[{0}])
>         LogicalProject(i=[true])
>           LogicalFilter(condition=[=($0, 2)])
>             LogicalTableScan(table=[[CATALOG, SALES, DEPT]])
> {noformat}



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