[jira] [Commented] (CALCITE-4333) The Sort rel should be decorrelated even though it has fetch or limit when its parent is not a Correlate

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

    [ https://issues.apache.org/jira/browse/CALCITE-4333?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17248015#comment-17248015 ] 

Ruben Q L commented on CALCITE-4333:
------------------------------------

[~danny0405] unfortunately, the proposed fix is insufficient, as soon as the LogicalSort is not at the top of the plan (e.g. it is the input of a final LogicalProject), it is not decorrelated.
Example:
{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}

Expected:
{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}

But it 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}

> The Sort rel should be decorrelated even though it has fetch or limit when its parent is not a Correlate
> --------------------------------------------------------------------------------------------------------
>
>                 Key: CALCITE-4333
>                 URL: https://issues.apache.org/jira/browse/CALCITE-4333
>             Project: Calcite
>          Issue Type: Bug
>          Components: core
>    Affects Versions: 1.26.0
>            Reporter: Danny Chen
>            Assignee: Danny Chen
>            Priority: Major
>              Labels: pull-request-available
>             Fix For: 1.27.0
>
>          Time Spent: 1h 10m
>  Remaining Estimate: 0h
>
> Check this test in SqlToRelConverterTest:
> {code:java}
> @Test void testSortLimitWithCorrelateInput() {
>     final String sql = "" +
>         "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:
> {code:xml}
> 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]])
> {code}
> It actually can be decorrelated to:
> {code:xml}
> 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]])
> {code}



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