[CALCITE-6089] EnumerableSortedAggregate fails with ClassCastException: class X cannot be cast to class org.apache.calcite.runtime.FlatLists$ComparableList

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 1.35.0
• Component/s: core
• Assignee: Unassigned
• Reporter: Ruben Q L
• Created: 03/Nov/23 08:43
• Updated: 28/Feb/24 06:03

Description

The problem can be reproduced with this test (to be added e.g. into EnumerableSortedAggregateTest.java):

  @Test void sortedAggCountUnion() {
    tester(false, new HrSchema())
        .query(
            "select count(*) as c from ( "
                + "select * from emps where deptno=10 "
                + "union all "
                + "select * from emps where deptno=20)")
        .withHook(Hook.PLANNER, (Consumer<RelOptPlanner>) planner -> {
          planner.removeRule(EnumerableRules.ENUMERABLE_AGGREGATE_RULE);
          planner.addRule(EnumerableRules.ENUMERABLE_SORTED_AGGREGATE_RULE);
        })
        .explainContains(
            "EnumerableSortedAggregate(group=[{}], c=[COUNT()])\n"
            + "  EnumerableUnion(all=[true])\n"
            + "    EnumerableCalc(expr#0..4=[{inputs}], expr#5=[CAST($t1):INTEGER NOT NULL], expr#6=[10], expr#7=[=($t5, $t6)], commission=[$t4], $condition=[$t7])\n"
            + "      EnumerableTableScan(table=[[s, emps]])\n"
            + "    EnumerableCalc(expr#0..4=[{inputs}], expr#5=[CAST($t1):INTEGER NOT NULL], expr#6=[20], expr#7=[=($t5, $t6)], commission=[$t4], $condition=[$t7])\n"
            + "      EnumerableTableScan(table=[[s, emps]])")
        .returnsOrdered(
            "c=4");
  }

Which fails with:

...
Caused by: java.lang.ClassCastException: class java.lang.Integer cannot be cast to class org.apache.calcite.runtime.FlatLists$ComparableList (java.lang.Integer is in module java.base of loader 'bootstrap'; org.apache.calcite.runtime.FlatLists$ComparableList is in unnamed module of loader 'app')
	at Baz$6.compare(Unknown Source)
	at org.apache.calcite.linq4j.EnumerableDefaults$SortedAggregateEnumerator.moveNext(EnumerableDefaults.java:938)
	at org.apache.calcite.linq4j.Linq4j$EnumeratorIterator.<init>(Linq4j.java:679)
	at org.apache.calcite.linq4j.Linq4j.enumeratorIterator(Linq4j.java:97)
...

The same test with EnumerableAggregate (instead of EnumerableSortedAggregate) will execute the query correctly.

Issue Links

• is related to: CALCITE-6087 EnumerableSortedAggregate returns incorrect result when input is empty
• is related to: CALCITE-4008 Implement Code generation for EnumerableSortedAggregate