Re: Writable foreign tables: how to identify rows

Merlin Moncure <mmoncure@gmail.com> writes:
> As long as lock as held between ctid examination and row modification
> you are ok.  didn't read the patch, just pointing that out (history is
> full of client side drivers that did not do this properly).

> I also might have missed some of the finer contextual points of the
> discussion here: I was thinking that you are identifying rows on the
> client over fetch transaction A to write back in transaction B.  If
> that is the case, ctid based identification to me is full of issues

Absolutely --- you can't rely on ctid across transactions.  postgres_fdw
isn't doing that though, just using it to update or delete rows that it
locked earlier in the same remote transaction.
        regards, tom lane