[CALCITE-2857] Complicated plan generated for subuqery with both equi and non-equi condition

• Type: Improvement
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: core
• Labels: sub-query
• Assignee: Unassigned
• Reporter: godfrey he
• Created: 20/Feb/19 08:44
• Updated: 03/Jun/19 23:15

Description

SemiJoin extends Join directly instead of EquiJoin to support non-equi condition,
e.g.

select * from (select * from dept where dept.deptno in (select emp.deptno from emp where emp.job <> dept.name))R where R.deptno <= 10

Currently, this query will be converted to

SemiJoin(condition=[AND(=($1, $3), =($0, $2))], joinType=[inner])
  LogicalFilter(condition=[<=($0, 10)])
    LogicalTableScan(table=[[CATALOG, SALES, DEPT]])
  LogicalProject(DEPTNO=[$7], NAME=[$9])
    LogicalJoin(condition=[<>($2, $9)], joinType=[inner])
      LogicalTableScan(table=[[CATALOG, SALES, EMP]])
      LogicalAggregate(group=[{0}])
        LogicalProject(NAME=[$1])
          LogicalTableScan(table=[[CATALOG, SALES, DEPT]])

however the following plan is more efficient than the above one:

LogicalProject(DEPTNO=[$0], NAME=[$1])
  LogicalFilter(condition=[<=($0, 10)])
    SemiJoin(condition=[=AND(=($0, $3), <>($1, $2))], joinType=[inner])
      LogicalTableScan(table=[[CATALOG, SALES, DEPT]])
      LogicalProject(JOB=[$2], DEPTNO=[$7])
        LogicalTableScan(table=[[CATALOG, SALES, EMP]])

Issue Links

• is related to: CALCITE-2968 New AntiJoin relational expression
• is related to: CALCITE-2969 Improve design of join-like relational expressions
• is related to: CALCITE-3089 Deprecate EquiJoin