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https://issues.apache.org/jira/browse/CALCITE-4206?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17188377#comment-17188377
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Danny Chen edited comment on CALCITE-4206 at 9/1/20, 11:44 AM:
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To fix this issue, i plan to add a protection when decorrelate the sort, like
this
{code:java}
public Frame decorrelateRel(Sort rel) {
// Can not decorrelate if the sort has per-correlate-key attributes like
// offset or fetch limit, because these attributes scope would change to
// global after decorrelation. They should take effect within the scope
// of the correlation key actually.
if (rel.offset != null || rel.fetch != null) {
return null;
}
{code}
A surprising result is test
{{SqlToRelConverterTest.testExistsCorrelatedLimitDecorrelate}} was also fixed.
was (Author: danny0405):
To fix this issue, i plan to add a protection when decorrelate the sort, like
this
{code:java}
public Frame decorrelateRel(Sort rel) {
if (rel.offset != null || rel.fetch != null) {
return null;
}
{code}
A surprising result is test
{{SqlToRelConverterTest.testExistsCorrelatedLimitDecorrelate}} was also fixed.
> RelDecorrelator outputs wong 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
> Fix For: 1.26.0
>
>
> 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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