方解石谓词下推

Question

Source SQL

SELECT  e . *
FROM    emp e
INNER JOIN    dept d
ON      e.deptno = d.deptno
AND     emp.deptno = 5;

After Optimzie

select
  e.
from
  (
    select
      *
    from
      emp
    where
      emp.deptno = 5
  ) e
  inner join (
    select
      *
    from
      deptno
    where
      deptno = 5
  ) on on e.deptno = d.deptno;

Does Calcite have this optimization rule?

Answer 1

Yes, there was CoreRules.JOIN_CONDITION_PUSH . But the only emp.deptno = 5 can be pushed into table emp. The transitive conditioin can be implement by your self.