[jira] [Created] (CALCITE-4437) The Sort rel should be decorrelated even though it has fetch or limit when it is not inside a Correlate

["Ruben Q L (Jira)" <ji...@apache.org>]

Ruben Q L created CALCITE-4437:
----------------------------------

             Summary: The Sort rel should be decorrelated even though it has fetch or limit when it is not inside a Correlate
                 Key: CALCITE-4437
                 URL: https://issues.apache.org/jira/browse/CALCITE-4437
             Project: Calcite
          Issue Type: Bug
          Components: core
    Affects Versions: 1.26.0
            Reporter: Ruben Q L
             Fix For: 1.27.0


The fix applied for CALCITE-4206 was "too drastic" and it resulted in Sort with fetch/offset being impossible to decorrelate in all cases.
CALCITE-4333 addressed this issue but only partially (when the Sort with fetch/offset is on top on the plan). However, this solution is insufficient, because any Sort with fetch/offset that is not inside a Correlate can be decorrelated.

Check this test in SqlToRelConverterTest:
{code}
  @Test void testSortLimitWithCorrelateInput2() {
    final String sql = ""
        + "SELECT ename||deptno FROM\n"
        + "(SELECT deptno, ename\n"
        + "    FROM\n"
        + "        (SELECT DISTINCT deptno FROM emp) t1,\n"
        + "          LATERAL (\n"
        + "            SELECT ename, sal\n"
        + "            FROM emp\n"
        + "            WHERE deptno = t1.deptno)\n"
        + "    ORDER BY ename DESC\n"
        + "    LIMIT 3)";
    sql(sql).ok();
  }
{code}

The current plan is:
{noformat}
LogicalProject(EXPR$0=[||($1, CAST($0):VARCHAR NOT NULL)])
  LogicalSort(sort0=[$1], dir0=[DESC], fetch=[3])
    LogicalProject(DEPTNO=[$0], ENAME=[$1])
      LogicalCorrelate(correlation=[$cor0], joinType=[inner], requiredColumns=[{0}])
        LogicalAggregate(group=[{0}])
          LogicalProject(DEPTNO=[$7])
            LogicalTableScan(table=[[CATALOG, SALES, EMP]])
        LogicalProject(ENAME=[$1], SAL=[$5])
          LogicalFilter(condition=[=($7, $cor0.DEPTNO)])
            LogicalTableScan(table=[[CATALOG, SALES, EMP]])
{noformat}

It can actually decorrelated as:
{noformat}
LogicalProject(EXPR$0=[||($1, CAST($0):VARCHAR NOT NULL)])
  LogicalSort(sort0=[$1], dir0=[DESC], fetch=[3])
    LogicalProject(DEPTNO=[$0], ENAME=[$1])
      LogicalJoin(condition=[=($0, $3)], joinType=[inner])
        LogicalAggregate(group=[{0}])
          LogicalProject(DEPTNO=[$7])
            LogicalTableScan(table=[[CATALOG, SALES, EMP]])
        LogicalProject(ENAME=[$1], SAL=[$5], DEPTNO=[$7])
          LogicalTableScan(table=[[CATALOG, SALES, EMP]])
{noformat}





--
This message was sent by Atlassian Jira
(v8.3.4#803005)