Re: foreign key locks

Excerpts from Tom Lane's message of mié jun 20 12:54:24 -0400 2012:
> Jaime Casanova <jaime@2ndquadrant.com> writes:
> > On Thu, Jun 14, 2012 at 11:41 AM, Alvaro Herrera
> > <alvherre@alvh.no-ip.org> wrote:
> >> This is v12 of the foreign key locks patch.
>
> > Just noticed that this patch needs a rebase because of the refactoring
> > Tom did in ri_triggers.c
>
> Hold on a bit before you work on that code --- I've got one more bit of
> hacking I want to try before walking away from it.  I did some oprofile
> work on Dean's example from
> <CAEZATCWm8M00RA814o4DC2cD_aj44gQLb0tDdxMHA312qg7HCQ@mail.gmail.com>
> and noticed that it looks like ri_FetchConstraintInfo is eating a
> noticeable fraction of the runtime, which is happening because it is
> called to deconstruct the relevant pg_constraint row for each tuple
> we consider firing the trigger for (and then again, if we do fire the
> trigger).  I'm thinking it'd be worth maintaining a backend-local cache
> for the deconstructed data, and am going to go try that.

I had merged already when I got your email, but merging that additional
change did not cause any conflicts.  So here's the rebased version.

--
Álvaro Herrera <alvherre@commandprompt.com>
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