Details
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Improvement
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Status: Closed
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Critical
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Resolution: Fixed
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None
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None
Description
The Correlate is not currently supported when metadata gets the column origin.(RelMdColumnOrigins#getColumnOrigins)
If a column is processed from a correlation variable, the correlation variable is ignored and the rest of the columns are returned.
In fact, we should return null for cases that cannot be determined.
@Test void testColumnOriginsForCorrelate() {
final String sql = "select (select max(dept.name || '_' || emp.ename)"
+ "from dept where emp.deptno = dept.deptno) from emp";
final RelMetadataFixture fixture = sql(sql);
final HepProgramBuilder programBuilder = HepProgram.builder();
programBuilder.addRuleInstance(CoreRules.PROJECT_SUB_QUERY_TO_CORRELATE);
final HepPlanner planner = new HepPlanner(programBuilder.build());
planner.setRoot(fixture.toRel());
final RelNode optimizedRel = planner.findBestExp();
fixture.withRelTransform(a -> optimizedRel.getInput(0).getInput(1))
.assertColumnOriginSingle("DEPT", "NAME", true);
}
OptimizeRel：
LogicalProject(EXPR$0=[$9])
LogicalCorrelate(correlation=[$cor1], joinType=[left], requiredColumns=[{1, 7}])
LogicalTableScan(table=[[CATALOG, SALES, EMP]])
LogicalAggregate(group=[{}], EXPR$0=[MAX($0)])
LogicalProject($f0=[||(||($1, '_'), $cor1.ENAME)])
LogicalFilter(condition=[=($cor1.DEPTNO, $0)])
LogicalTableScan(table=[[CATALOG, SALES, DEPT]])