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