Re: Expression errors with "FOR UPDATE" and postgres_fdw with partition wise join enabled.

Hi Ashutosh, Etsuro, Robert,

On 2018-06-22 10:58:28 -0400, Robert Haas wrote:
> On Tue, Jun 19, 2018 at 8:46 AM, Etsuro Fujita
> <fujita(dot)etsuro(at)lab(dot)ntt(dot)co(dot)jp> wrote:
> > Here is a patch for that.
> >
> > * As I said upthread, the patch makes code much more simple; I removed all
> > the changes to setrefs.c added by the partitionwise-join patch. I also
> > simplified the logic for building a tlist for a child-join rel. The original
> > PWJ computes attr_needed data even for child rels, and build the tlist for a
> > child-join by passing to build_joinrel_tlist that data for input child rels
> > for the child-join. But I think that's redundant, and it's more
> > straightforward to apply adjust_appendrel_attrs to the parent-join's tlist
> > to get the child-join's tlist. So, I changed that way, which made
> > unnecessary all the changes to build_joinrel_tlist and placeholder.c added
> > by the PWJ patch, so I removed those as well.
> >
> > * The patch contains all of the regression tests in the original patch
> > proposed by Ashutosh.
>
> I think this approach is going to run into trouble if the level at
> which we have to apply the ConvertRowTypeExpr happens not to be a
> projection-capable node.

What's the plan forward here? This has been an open item for quite a
while. Robert, are you in agreement with this approach on a high level?
Who is going to drive this forward?

Greetings,

Andres Freund