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https://issues.apache.org/jira/browse/CALCITE-6193?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17806226#comment-17806226
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Julian Hyde commented on CALCITE-6193:
--------------------------------------
[~4wei], Is this a good summary of the case:
{quote}
If a query has more than one subexpression that matches a materialized view,
only the first is substituted
{quote}
And then explain that it happens only when (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, and (b) the matching fragments require
some compensation.
If you agree, then the above should become the jira subject and commit message.
I don't have an opinion about the right fix - you and [~jiajunbernoulli] should
figure that out. But in any case, let's get a fix into 1.37.
> SubstitutionVisitor stop trying incorrect subtree because of wrong parent
> relationship when replace query
> ---------------------------------------------------------------------------------------------------------
>
> 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.
> The root cause is that SubstitutionVisitor replace child nodes withÂ
> 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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