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https://issues.apache.org/jira/browse/CALCITE-6193?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17813494#comment-17813494
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Mou Wu edited comment on CALCITE-6193 at 2/2/24 6:40 AM:
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[~jiajunbernoulli] OK, I want to know whether there are any examples that I can 
follow, otherwise a unofficial benchmark may be produced.


was (Author: JIRAUSER290047):
[~jiajunbernoulli] OK, I wonder whether there are any examples that I can 
follow, otherwise a unofficial benchmark may be produced.

> If a query has more than one subexpression that matches a materialized view, 
> only the first is substituted
> ----------------------------------------------------------------------------------------------------------
>
>                 Key: CALCITE-6193
>                 URL: https://issues.apache.org/jira/browse/CALCITE-6193
>             Project: Calcite
>          Issue Type: Bug
>            Reporter: Mou Wu
>            Assignee: Mou Wu
>            Priority: Major
>              Labels: pull-request-available
>             Fix For: 1.37.0
>
>
> {code:java}
> @Test void testStopTryIncorrectSubtree() {
>   final String mv = ""
>       + "select \"empid\", \"deptno\"\n"
>       + "from \"emps\"\n"
>       + "where \"salary\" > 1000\n"
>       + "group by \"empid\", \"deptno\"";
>   final String query = ""
>       + "select t1.\"deptno\"\n"
>       + "from (\n"
>       + "select \"deptno\"\n"
>       + "from \"emps\"\n"
>       + "where \"salary\" > 1000\n"
>       + "union all\n"
>       + "select \"deptno\"\n"
>       + "from \"emps\"\n"
>       + "where \"salary\" > 1000\n"
>       + "group by \"deptno\"\n"
>       + ") as t1 inner join (\n"
>       + "select \"deptno\"\n"
>       + "from \"emps\"\n"
>       + "where \"salary\" > 1000\n"
>       + "group by \"deptno\"\n"
>       + ") as t2 on t1.\"deptno\" = t2.\"deptno\"\n";
>   sql(mv, query)
>       .checkingThatResultContains(""
>           + "LogicalCalc(expr#0..1=[{inputs}], deptno=[$t0])\n"
>           + "  LogicalJoin(condition=[=($0, $1)], joinType=[inner])\n"
>           + "    LogicalUnion(all=[true])\n"
>           + "      LogicalCalc(expr#0..4=[{inputs}], expr#5=[1000], 
> expr#6=[>($t3, $t5)], deptno=[$t1], $condition=[$t6])\n"
>           + "        LogicalTableScan(table=[[hr, emps]])\n"
>           + "      LogicalAggregate(group=[{1}])\n"
>           + "        EnumerableTableScan(table=[[hr, MV0]])\n"
>           + "    LogicalAggregate(group=[{1}])\n"
>           + "      EnumerableTableScan(table=[[hr, MV0]])"
>       ).ok();
> }{code}
> The test case above will fail because the second mv0 not be matched.
> Two conditions these kind of bug matchs:
> (a) There is a third expression, earlier in the view, that has a 
> subexpression in common with the matching fragments but does not match the 
> view.
> (b) The matching fragments require some compensation.
> The root cause is that SubstitutionVisitor replace child nodes with 
> targetDescendant node itself, not a deep-copy replica, so they may share the 
> same node and the same parent node, thus the incorrect parent relationship 
> may occur, it will make stopTrying be wrong.



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