Re: Writable foreign tables: how to identify rows

On Wed, Mar 6, 2013 at 11:06 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Shigeru Hanada <shigeru.hanada@gmail.com> writes:
>> I'm not sure whether postgres_fdw should support, but updatable views
>> have no system column including ctid.  So, we need magic identifier,
>> perhaps it would be set of primary key value(s), to support updating
>> remote updatable views via foreign tables.
>
> Yeah, I considered that.  I thought seriously about proposing that we
> forget magic row identifiers altogether, and instead make postgres_fdw
> require a remote primary key for a foreign table to be updatable.

IMO, Utilizing anything but this for remote record identification is
an implementation specific optimization.  Aren't the semantics
different though?  If you go:

update foo set id = 1 where id = 1;

the primary key would not change, but the ctid would.  or is that
already a handled?

merlin