[CALCITE-4040] Materialized View matching failed with NPE if aggregate function doesn't support roll up

• Type: Wish
• Status: Closed
• Priority: Major
• Resolution: Resolved
• Fix Version/s: 1.24.0
• Assignee: Unassigned
• Reporter: xzh_dz
• Created: 03/Jun/20 10:10
• Updated: 28/May/21 10:12
• Resolved: 10/Jun/20 02:28

Description

When i try to rollup some SqlAggFunctions in my project,I find something wrong.
A case can be reproduced as below:
MaterializationTest:

@Test public void testSqlAggFunctionRollup() {
    checkNoMaterialize(
        "select \"empid\", stddev_pop(\"deptno\") from \"emps\" group by \"empid\", \"deptno\"",
        "select \"empid\", stddev_pop(\"deptno\") from \"emps\" group by \"empid\"",
        HR_FKUK_MODEL);
  }

When an aggregate function does not support roll up, materialization recognition should fail and return the original relnode instead of throwing an exception.
Exception:

java.sql.SQLException: Error while executing SQL "explain plan for select "empid", stddev_pop("deptno") from "emps" group by "empid"": null

	at org.apache.calcite.avatica.Helper.createException(Helper.java:56)
	at org.apache.calcite.avatica.Helper.createException(Helper.java:41)
	at org.apache.calcite.avatica.AvaticaStatement.executeInternal(AvaticaStatement.java:163)
	at org.apache.calcite.avatica.AvaticaStatement.executeQuery(AvaticaStatement.java:227)
	at org.apache.calcite.test.CalciteAssert.assertQuery(CalciteAssert.java:528)
Caused by: java.lang.NullPointerException
	at java.util.Objects.requireNonNull(Objects.java:203)
	at org.apache.calcite.rel.core.AggregateCall.<init>(AggregateCall.java:98)
	at org.apache.calcite.rel.core.AggregateCall.create(AggregateCall.java:198)
	at org.apache.calcite.plan.SubstitutionVisitor.unifyAggregates(SubstitutionVisitor.java:1854)
	at org.apache.calcite.plan.SubstitutionVisitor$AggregateToAggregateUnifyRule.apply(SubstitutionVisitor.java:1545)
	at org.apache.calcite.plan.SubstitutionVisitor.go(SubstitutionVisitor.java:544)
	at org.apache.calcite.plan.SubstitutionVisitor.go(SubstitutionVisitor.java:478)

Issue Links

• links to: https://github.com/apache/calcite/pull/2000