[jira] [Commented] (CALCITE-4206) RelDecorrelator outputs wrong plan for correlate sort with fetch limit

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

    [ https://issues.apache.org/jira/browse/CALCITE-4206?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17188693#comment-17188693 ] 

Julian Hyde commented on CALCITE-4206:
--------------------------------------

Does this mean that we cannot decorrelate if there is a sort-limit? That's a problem, because some execution are not able to execute correlated queries. (It's still preferable to current behavior, namely to change semantics during decorrelation.)

> RelDecorrelator outputs wrong plan for correlate sort with fetch limit
> ----------------------------------------------------------------------
>
>                 Key: CALCITE-4206
>                 URL: https://issues.apache.org/jira/browse/CALCITE-4206
>             Project: Calcite
>          Issue Type: Bug
>          Components: core
>    Affects Versions: 1.25.0
>            Reporter: Danny Chen
>            Assignee: Danny Chen
>            Priority: Major
>              Labels: pull-request-available
>             Fix For: 1.26.0
>
>          Time Spent: 10m
>  Remaining Estimate: 0h
>
> For query
> {code:sql}
> SELECT deptno, ename
>   FROM
>     (SELECT DISTINCT deptno FROM emp) t1,
>       LATERAL (
>         SELECT ename, sal
>         FROM emp
>         WHERE deptno = t1.deptno
>         ORDER BY sal
>         DESC LIMIT 3
>       )
> {code}
> The current plan after decorrelation is
> {code:xml}
> LogicalProject(DEPTNO=[$0], ENAME=[$1])
>   LogicalJoin(condition=[=($0, $3)], joinType=[inner])
>     LogicalAggregate(group=[{0}])
>       LogicalProject(DEPTNO=[$7])
>         LogicalTableScan(table=[[CATALOG, SALES, EMP]])
>     LogicalSort(sort0=[$1], dir0=[DESC], fetch=[3])
>       LogicalProject(ENAME=[$1], SAL=[$5], DEPTNO=[$7])
>         LogicalTableScan(table=[[CATALOG, SALES, EMP]])
> {code}
> which is wrong, because the partition sort(on sal) changes to global.



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