Re: PostgreSQL + SMP

* Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> [001210 12:28] wrote:
> > * Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> [001210 12:19] wrote:
> > > > Postgre is not threaded, but every connection gets it's own process. The OS
> > > > will distribute the processes across the processors. Not sure I said that
> > > > very will.
> > > >
> > > > Basically a single connection will not be any faster with SMP, but multiple
> > > > connections will be.
> > >
> > > Actually, even a single process will be faster because all other system
> > > process will run on other cpu's.
> >
> > Depending on how idle you are, the large overhead of bus locking
> > can cause a lot of perf degredation(sp?) for the idle SMP case.
>
> True. I was thinking more of the backend having to give up the cpu to
> allow other processes to run. With two cpu's, I believe one backend can
> camp out on a cpu forever as long as the other cpu doesn't get busy.

That's true, as long as there's no contention for the locks then it's
pretty cheap.

--
-Alfred Perlstein - [bright(at)wintelcom(dot)net|alfred(at)freebsd(dot)org]
"I have the heart of a child; I keep it in a jar on my desk."