On Mon, Oct 6, 2014 at 8:35 AM, Robert Haas <robertmhaas@gmail.com> wrote:
> I think the problem is that it's not possible to respect the "usual
> guarantees" even at READ COMMITTED level when performing an INSERT OR
> UPDATE operation (however spelled). You may find that there's a tuple
> with the same PK which is committed but not visible to the snapshot
> you took at the beginning of the statement.
Can you please comment on this, Kevin? It would be nice to converge on
an agreement on syntax here (without necessarily working out the exact
details right away, including for example the exact spelling of what
I'm calling WITHIN). Since Simon has changed his mind on MERGE (while
still wanting to retain a superficial flavor of MERGE, a flavor that
does not include the MERGE keyword), I think that leaves you as the
only advocate for the MERGE syntax.
--
Peter Geoghegan