Re: Writable foreign tables: how to identify rows

Merlin Moncure <mmoncure(at)gmail(dot)com> writes:
> I just find it odd that rowid concept is used at all without strong
> guarantee that the record you are referencing is the one you are
> supposed to be referencing. Basically I'm saying PKEY semantics are
> the correct ones and that ctid is ok to use iff they match the pkey
> ones. I don't think this is possible unless you maintain a remote
> lock on the ctid between when you fetch it and do some other
> operation.

postgres_fdw does maintain such a lock (it does SELECT FOR UPDATE when
scanning an update/delete target table). However, I'm not exactly sure
why you think a pkey-based design would be free of such hazards. pkeys
aren't immutable either ...

regards, tom lane