Re: INSERT...ON DUPLICATE KEY LOCK FOR UPDATE

On 2013-12-23 14:59:31 -0800, Peter Geoghegan wrote:
> On Mon, Dec 23, 2013 at 7:49 AM, Robert Haas <robertmhaas@gmail.com> wrote:
> > I don't think this is a project to rush through.  We've lived without
> > MERGE/UPSERT for several years now, and we can live without it for
> > another release cycle while we try to reach agreement on the way
> > forward.

Agreed, but I really think it's one of the biggest weaknesses of
postgres at this point.

> >  I can tell that you're convinced you know the right way
> > forward here, and you may be right, but I don't think you've convinced
> > everyone else - maybe not even anyone else.

> That may be. Attention from reviewers has been in relatively short
> supply. Not that that isn't always true.

I don't really see the lack of review as being crucial at this point. At
least I have quite some doubts about the approach you've chosen and I
have voiced it - so have others. Whether yours is workable seems to
hinge entirely on whether you can build a scalable, maintainable
value-locking scheme. Besides some thoughts about using slru.c for it I
haven't seen much about the design of that part - might just have missed
it though. Personally I can't ad-lib a design for it, but I haven't
though about it too much.
I don't think there's too much reviewers can do before you've provided a
POC implementation of real value locking.

Greetings,

Andres Freund

-- Andres Freund                       http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training &
Services