[CALCITE-2865] FilterProjectTransposeRule generates wrong traitSet when copyFilter/Project is true

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.18.0
• Fix Version/s: 1.20.0
• Labels: pull-request-available
• Assignee: Ruben Q L
• Reporter: Ruben Q L
• Created: 25/Feb/19 09:57
• Updated: 24/Jun/19 15:01
• Resolved: 18/Apr/19 21:51

Description

Problem can be reproduced with the following steps:

As suggested by zabetak, a possibility to reproduce this issue is with the following test in RelOptRulesTest:

  /** Test case for
   * <a href="https://issues.apache.org/jira/browse/CALCITE-2865">[CALCITE-2865]
   * FilterProjectTransposeRule generates wrong traitSet when copyFilter/Project is true</a>. */
  @Test public void testFilterProjectTransposeRule() {
    List<RelOptRule> rules = Arrays.asList(
            FilterProjectTransposeRule.INSTANCE, // default values: copyFilter=true, copyProject=true
            new FilterProjectTransposeRule(Filter.class, Project.class, /*copyFilter*/ false, /*copyProject*/ false, RelFactories.LOGICAL_BUILDER));

    List<RelNode> results = new ArrayList<>(2);

    for (RelOptRule rule : rules) {
      RelBuilder b = RelBuilder.create(RelBuilderTest.config().build());
      RelNode in = b
              .scan("EMP")
              .sort(-4) // salary desc
              .project(b.field(3)) // salary
              .filter(b.equals(b.field(0), b.literal(11500))) // salary = 11500
              .build();
      HepProgram program = new HepProgramBuilder()
              .addRuleInstance(rule)
              .build();
      HepPlanner hepPlanner = new HepPlanner(program);
      hepPlanner.setRoot(in);
      results.add(hepPlanner.findBestExp());
    }
    // compare LogicalFilter traitSet
    assertEquals(results.get(0).getInput(0).getTraitSet(), results.get(1).getInput(0).getTraitSet());
  }

Which fails with the following message:

java.lang.AssertionError: 
Expected :NONE.[0 DESC]
Actual   :NONE.[3 DESC]

If we run the test with a break point at the end of FilterProjectTransposeRule#onMatch method, we can see that, when the project and filter are transposed, the generated output (newFilterRel) is different in terms of traitSet, depending if the copyFilter / copyProject flags are used or not:

• copyFilter and copyProject TRUE (default)

  LogicalProject.NONE.[0 DESC] 
      LogicalFilter.NONE.[0 DESC] // !!! 
          LogicalSort.NONE.[3 DESC] 
  

• copyFilter and copyProject FALSE

  LogicalProject.NONE.[0 DESC] 
      LogicalFilter.NONE.[3 DESC] // !!! 
          LogicalSort.NONE.[3 DESC] 
  

As I see it, the default behavior (copyFilter/Project true) seems wrong in terms of new filter's traitSet.

Issue Links

• links to: GitHub Pull Request #1130