Re: Status of FDW pushdowns

On Wed, Nov 27, 2013 at 10:29:34AM -0300, Alvaro Herrera wrote:
> Shigeru Hanada escribió:
>
> > SQL/MED standard doesn't say much about PASS THROUGH mode, especially
> > about interaction between client. Besides it, I think it would be
> > nice to allow arbitrary FDW as backend of dblink interface like this:
> >
> > postgres=> SELECT dblink_connect('con1', 'server name of an FDW');
> > postgres=> SELECT * FROM dblink('con1', 'some query written in remote
> > syntax') as t(/* record type definition */...);
> >
> > This provides a way to execute query without defining foreign table.
>
> Seems to me that if you want to read remote tables without creating a
> foreign table, you could define them locally using something like the
> WITH syntax and then use them normally in the rest of the query.

WITH, or SRF, or whatever, the point is that we need to be able to
specify what we're sending--probably single opaque strings delimited
just as we do other strings--and what we might get back--errors only,
rows, [sets of] refcursors are the ones I can think of offhand.

What we can't do is assume that our parser needs to, or even could, in
principle, understand these things in more detail than that.

Cheers,
David.
--
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