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https://issues.apache.org/jira/browse/CALCITE-3926?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
ASF GitHub Bot updated CALCITE-3926:
------------------------------------
Labels: pull-request-available (was: )
> CannotPlanException when an empty LogicalValues requires a certain collation
> ----------------------------------------------------------------------------
>
> Key: CALCITE-3926
> URL: https://issues.apache.org/jira/browse/CALCITE-3926
> Project: Calcite
> Issue Type: Bug
> Components: core
> Affects Versions: 1.23.0
> Reporter: Ruben Q L
> Priority: Blocker
> Labels: pull-request-available
>
> The issue can be reproduced with the following test (in RelBuilderTest.java):
> {code:java}
> @Test void testEmptyValues() throws Exception {
> final RelBuilder builder = RelBuilder.create(config().build());
> final RelNode root =
> builder
> .scan("DEPT")
> .filter(builder.literal(false)) // generates an empty
> LogicalValues
> .sort(
> builder.field("DNAME"),
> builder.field("DEPTNO"))
> .build();
> try (PreparedStatement preparedStatement = RelRunners.run(root)) {
> final String s =
> CalciteAssert.toString(preparedStatement.executeQuery());
> final String result = "";
> assertThat(s, is(result));
> }
> }
> {code}
> The test fails with the following message:
> {code:java}
> Caused by: org.apache.calcite.plan.RelOptPlanner$CannotPlanException: There
> are not enough rules to produce a node with desired properties:
> convention=ENUMERABLE, sort=[1, 0].
> Missing conversion is LogicalValues[convention: NONE -> ENUMERABLE, sort:
> [[0, 1, 2], [1, 2], [2]] -> [1, 0]]
> There is 1 empty subset: rel#14:Subset#0.ENUMERABLE.[1, 0], the relevant part
> of the original plan is as follows
> 1:LogicalValues(tuples=[[]])
> {code}
> The issue seems to be caused by the empty values: Scan + Filter(false) =>
> LogicalValues(tuples=[[]]).
> This empty LogicalValues has as collation (in case of 3 fields): [[0, 1, 2],
> [1, 2], [2]]; and in the plan we are requesting as sort collation [1, 0].
> This could be achieved by: EnumerableSort(sort=[1,0]) +
> EnumerableValues(tuples=[[]]) ; but for some reason this plan is not
> generated.
> It seems the issue was somehow introduced by CALCITE-3886
>
> [https://github.com/apache/calcite/commit/08f4a9889728f94903ff424ed9c20d940b821af5]
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