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

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.

--  Bruce Momjian  <bruce@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com
 + Everyone has their own god. +