Re: foreign join error "variable not found in subplan target list"

Richard Guo <guofenglinux@gmail.com>

From: Richard Guo <guofenglinux@gmail.com>
To: Etsuro Fujita <etsuro.fujita@gmail.com>
Cc: Alexander Pyhalov <a.pyhalov@postgrespro.ru>, PostgreSQL mailing lists <pgsql-bugs@lists.postgresql.org>
Date: 2022-09-13T02:28:42Z
Lists: pgsql-bugs
On Mon, Sep 12, 2022 at 12:19 PM Etsuro Fujita <etsuro.fujita@gmail.com>
wrote:

> On Wed, Aug 31, 2022 at 6:52 PM Etsuro Fujita <etsuro.fujita@gmail.com>
> wrote:
> > On Wed, Aug 31, 2022 at 6:27 PM Richard Guo <guofenglinux@gmail.com>
> wrote:
> > > Hmm, yes, the EPQ path does not need to compete with others in
> add_path,
> > > so its cost does not matter too much. And the comment just above
> > > GetExistingLocalJoinPath says:
> > >
> > >  * Since the plan created using this path will presumably only be used
> to
> > >  * execute EPQ checks, efficiency of the path is not a concern.
> > >
> > > But still I feel it's not a good practice to not update the cost and
> > > width fields after calling add_new_columns_to_pathtarget(). How about
> we
> > > add some comments here explaining why we do not need to adjust the
> > > estimates for the EPQ path?
> >
> > I agree with you on that point.  I’ll update the patch as such in the
> > next version.
>
> Here is an updated patch for that.  Other changes:
>
> * I modified the patch so that we adjust the tlist of the EPQ path if
> necessary, using the idea discussed upthread.
> * I tweaked other comments a little bit.


+1. The new patch looks good to me.

Thanks
Richard

Commits

  1. postgres_fdw: Avoid 'variable not found in subplan target list' error.