Re: Making joins involving ctid work for the benefit of UPSERT

On Tue, Jul 29, 2014 at 9:56 AM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> I think it would be advisable to separate the syntax from the
> implementation. Presumably you can make your implementation use some
> reasonable syntax we can all agree on, and conversely my proposed
> syntax could be made to have a different set of semantics. There's
> some connection between the syntax and semantics, of course, but it's
> not 100%. I mention this because I was mostly concerned with getting
> to a reasonable syntax proposal, not so much the implementation
> details. It may well be that your implementation details are perfect
> at this point; I don't know because I haven't looked, and I'm not an
> expert on that area of the code anyway. But I have looked at your
> syntax, which I wasn't altogether keen on.

Fair enough. I think the syntax should reflect the fact that upserts
are driven by inserts, though. Users will get into trouble with a
syntax that allows a predicate that is evaluated before any rows are
locked.

--
Peter Geoghegan