Re: Pulling up direct-correlated ANY_SUBLINK

On Thu, Sep 12, 2019 at 11:35 PM Antonin Houska <ah(at)cybertec(dot)at> wrote:

> Richard Guo <riguo(at)pivotal(dot)io> wrote:
>
> > On Wed, Sep 11, 2019 at 3:25 PM Antonin Houska <ah(at)cybertec(dot)at>
> > wrote:
> >
> >
> > Nevertheless, I don't know how to overcome the problems that I
> > mentioned
> > upthread.
> >
> >
> > Do you mean the problem "the WHERE clause of the subquery didn't
> > participate in the SEMI JOIN evaluation"? Good news is it has been
> > fixed
> > by commit 043f6ff0 as I mentioned upthread.
>
> Do you say that my old patch (rebased) no longer breaks the regression
> tests?
>

I think so.

>
> (I noticed your other email in the thread which seems to indicate that
> you're
> no lo longer interested to work on the feature, but asking out of
> curiosity.)
>

Tom pointed out that even if we pull up the subquery with the help of
LATERAL, we cannot make sure we will end up with a better plan, since
LATERAL pretty much constrains things to use a nestloop. Hmm, I think
what he said makes sense.

Thanks
Richard