[CALCITE-4055] RelFieldTrimmer loses hints

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.23.0
• Fix Version/s: 1.24.0
• Component/s: core
• Labels: pull-request-available
• Assignee: Ruben Q L
• Reporter: Ruben Q L
• Created: 09/Jun/20 10:36
• Updated: 25/Jul/20 14:59
• Resolved: 12/Jun/20 07:20

Description

The trimmed plan generated by RelFieldTrimmer can lose the hints that might be present in the input plan.
The issue can be reproduced with the following test (to be added to RelFieldTrimmerTest):

  @Test void testJoinWithHints() {
    final RelHint noHashJoinHint = RelHint.builder("NO_HASH_JOIN").inheritPath(0).build();
    final RelBuilder builder = RelBuilder.create(config().build());
    final RelNode original =
        builder.scan("EMP")
            .scan("DEPT")
            .join(JoinRelType.INNER,
                builder.equals(
                    builder.field(2, 0, "DEPTNO"),
                    builder.field(2, 1, "DEPTNO")))
            .hints(noHashJoinHint)
            .project(
                builder.field("ENAME"),
                builder.field("DNAME"))
            .build();

    final RelFieldTrimmer fieldTrimmer = new RelFieldTrimmer(null, builder);
    final RelNode trimmed = fieldTrimmer.trim(original);

    final String expected = ""
        + "LogicalProject(ENAME=[$1], DNAME=[$4])\n"
        + "  LogicalJoin(condition=[=($2, $3)], joinType=[inner])\n"
        + "    LogicalProject(EMPNO=[$0], ENAME=[$1], DEPTNO=[$7])\n"
        + "      LogicalTableScan(table=[[scott, EMP]])\n"
        + "    LogicalProject(DEPTNO=[$0], DNAME=[$1])\n"
        + "      LogicalTableScan(table=[[scott, DEPT]])\n";
    assertThat(trimmed, hasTree(expected));

    assertTrue(original.getInput(0) instanceof Join);
    final Join originalJoin = (Join) original.getInput(0);
    assertTrue(originalJoin.getHints().contains(noHashJoinHint));

    assertTrue(trimmed.getInput(0) instanceof Join);
    final Join join = (Join) trimmed.getInput(0);
    assertTrue(join.getHints().contains(noHashJoinHint));
  }

which fails in the last line: assertTrue(join.getHints().contains(noHashJoinHint));

Issue Links

• links to: PR#2015