Re: Spinlocks and semaphores in 9.2 and 9.3

On 2016-04-18 11:07:08 -0400, Tom Lane wrote:
> Andres Freund <andres(at)anarazel(dot)de> writes:
> > On April 16, 2016 6:02:39 PM PDT, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> >> I went ahead and prepared and tested such a patch; the version for 9.3
> >> is attached. (9.2 is identical modulo some pgindent-induced whitespace
> >> difference.) This doesn't look too hazardous to me, so I'm thinking
> >> we should apply it.
>
> > I can't look at the patch just now, but the plan sounds good. Of you rather have somebody look art the patch before, I can do tomorrow morning.
>
> Did you want to actually review this patch, or should I just push it?

No, I'm good, you should push it. I did a quick scan of the patch, and
it looks sane. For a second I was concerned that there might be a
situation in which this patch increases the total number of semaphore
needed, which might make backpatching a bit problematic - but it appears
that that'd be a very absurd configuration.

Greetings,

Andres Freund