[CALCITE-5784] Generate the same correlationId for the same query

• Type: Improvement
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: core
• Labels: pull-request-available
• Assignee: Unassigned
• Reporter: WenJun Min
• Created: 15/Jun/23 12:40
• Updated: 18/Jun/23 13:31

Description

Currently, the CTE query block will be sql2rel multiple times if be referenced multiple times. If it contains a lateral join, it will generate different correlation id. See below:

    String sql = "WITH a AS (SELECT ename, job, empno, r FROM emp, LATERAL TABLE (ramp(empno)) as T(r))"
        + " SELECT * from a a1, a a2 WHERE a1.r = a2.empno";
    sql(sql).ok();

LogicalProject(ENAME=[$0], JOB=[$1], EMPNO=[$2], R=[$3], ENAME0=[$4], JOB0=[$5], EMPNO0=[$6], R0=[$7])
  LogicalJoin(condition=[=($3, $6)], joinType=[inner])
    LogicalProject(ENAME=[$1], JOB=[$2], EMPNO=[$0], R=[$9])
      LogicalCorrelate(correlation=[$cor0], joinType=[inner], requiredColumns=[{0}])
        LogicalTableScan(table=[[CATALOG, SALES, EMP]])
        LogicalTableFunctionScan(invocation=[RAMP($cor0.EMPNO)], rowType=[RecordType(INTEGER I)])
    LogicalProject(ENAME=[$1], JOB=[$2], EMPNO=[$0], R=[$9])
      LogicalCorrelate(correlation=[$cor1], joinType=[inner], requiredColumns=[{0}])
        LogicalTableScan(table=[[CATALOG, SALES, EMP]])
        LogicalTableFunctionScan(invocation=[RAMP($cor1.EMPNO)], rowType=[RecordType(INTEGER I)])

It will generate two correlation id. In flink there is a subplan reuse based on the digest, the same query produce diff digest will break this functionality

Issue Links

• relates to: FLINK-32320 Same correlate can not be reused due to the different correlationId
• links to: GitHub Pull Request #3269