On Sat, Oct 15, 2022 at 3:27 AM Tom Lane wrote:
> Andy Fan writes:
> > After some more self review, I find my proposal has the following side
> > effects.
>
> Yeah, I do not think this works at all.
The discussion of outer join
> reordering in optimizer/README says that that doesn't work
Hi Tom:
Thanks for your reply! I have self reviewed the below message at 3 different
time periods to prevent from too inaccurate replies. It may be more detailed
than it really needed, but it probably can show where I am lost.
On Sat, Oct 15, 2022 at 3:27 AM Tom Lane wrote:
>
> If the pulled-up
Andy Fan writes:
> After some more self review, I find my proposal has the following side
> effects.
Yeah, I do not think this works at all. The mechanism as it stands
right now is that we can insert pulled-up semijoins above j->larg
if they only need variables from relations in j->larg, and we
>
> Later we tried to pull up the EXISTS sublink to t1 OR t2 *separately*,
> since
> this subselect referenced to t1 *AND* t2, so we CAN'T pull up the
> sublink. I
> am thinking why we have to pull up it t1 OR t2 rather than JoinExpr(t1,
> t2),
> I think the latter one is better.
>
After some more
Hi:
When I was working on another task, the following case caught my mind.
create table t1(a int, b int, c int);
create table t2(a int, b int, c int);
create table t3(a int, b int, c int);
explain (costs off) select * from t1
where exists (select 1 from t2
where exists (select 1 fr
