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https://issues.apache.org/jira/browse/CALCITE-4617?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18016990#comment-18016990
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Zhen Chen commented on CALCITE-4617:
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Original plan in jira summary:
{code:java}
LogicalProject(DEPTNO=[$0], EMPNO=[$2])
LogicalSort(offset=[2], fetch=[10])
LogicalJoin(condition=[=($0, $9)], joinType=[right])
LogicalTableScan(table=[[CATALOG, SALES, DEPT]])
LogicalSort(offset=[2], fetch=[10])
LogicalTableScan(table=[[CATALOG, SALES, EMP]])
{code}
The plan can be modified to
{code:java}
LogicalProject(DEPTNO=[$0], EMPNO=[$2])
LogicalSort(offset=[2], fetch=[10]) <-- keep it
here and no changes are needed
LogicalJoin(condition=[=($0, $9)], joinType=[right])
LogicalTableScan(table=[[CATALOG, SALES, DEPT]])
LogicalSort(offset=[0], fetch=[12]) <-- offset =
0, fetch = outer_offset + outer_fetch
LogicalTableScan(table=[[CATALOG, SALES, EMP]])
{code}
Can someone help me see if this logic is feasible?
> Wrong offset when SortJoinTransposeRule pushes a Sort with an offset
> --------------------------------------------------------------------
>
> Key: CALCITE-4617
> URL: https://issues.apache.org/jira/browse/CALCITE-4617
> Project: Calcite
> Issue Type: Bug
> Components: core
> Affects Versions: 1.26.0
> Reporter: Sylvain Crozon
> Assignee: Ruben Q L
> Priority: Major
> Labels: pull-request-available
> Time Spent: 2h
> Remaining Estimate: 0h
>
> The SortJoinTransposeRule will push a sort node past a join, and then
> duplicate the sort node on top of the join. When the sort node has an offset,
> we should only apply it once, otherwise we end up skipping twice as many rows
> as we should. The sort node added on top of the join should have a null
> offset.
>
> For example the testSortJoinTranspose6 test checks that for this initial plan
> {code}
> LogicalProject(DEPTNO=[$0], EMPNO=[$2])
> LogicalSort(offset=[2], fetch=[10])
> LogicalJoin(condition=[=($0, $9)], joinType=[right])
> LogicalTableScan(table=[[CATALOG, SALES, DEPT]])
> LogicalTableScan(table=[[CATALOG, SALES, EMP]])
> {code}
> the SortJoinTransposeRule should convert to
> {code}
> LogicalProject(DEPTNO=[$0], EMPNO=[$2])
> LogicalSort(offset=[2], fetch=[10])
> LogicalJoin(condition=[=($0, $9)], joinType=[right])
> LogicalTableScan(table=[[CATALOG, SALES, DEPT]])
> LogicalSort(offset=[2], fetch=[10])
> LogicalTableScan(table=[[CATALOG, SALES, EMP]])
> {code}
> Which will result in applying the offset twice. Instead the LogicalSort on
> top of the join should just have a null offset
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