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

["Volodymyr Vysotskyi (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CALCITE-2329?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16491016#comment-16491016 ] 

Volodymyr Vysotskyi commented on CALCITE-2329:
----------------------------------------------

I have created a pull request for this Jira: [https://github.com/apache/calcite/pull/700.] Could someone please review it?

> 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
>
> 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}



--
This message was sent by Atlassian JIRA
(v7.6.3#76005)