Re: [PATCH] PostgreSQL 9.4 mmap(2) performance regression on FreeBSD...

On Mon, Oct 13, 2014 at 11:35:18AM -0400, Bruce Momjian wrote:
> On Mon, Oct 13, 2014 at 05:21:32PM +0200, Andres Freund wrote:
> > > If we have it, we should improve it, or remove it. We might want to use
> > > this code for something else in the future, so it should be improved
> > > where feasible.
> >
> > Meh. We don't put in effort into code that doesn't matter just because
> > it might get used elsewhere some day. By that argument we'd need to
> > performance optimize a lot of code. And actually, using that code
> > somewhere else is more of a counter indication than a pro
> > argument. MAP_NOSYNC isn't a general purpose flag.
>
> The key is that this is platform-specific behavior, so if we should use
> a flag to use it right, we should. You are right that optimizing
> rarely used code with generic calls isn't a good use of time.

I have adjusted Sean's mmap() options patch to match our C layout and
plan to apply this to head, as it is from August.

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

+ Everyone has their own god. +