Re: libpq Win32 Mutex performance patch

On Fri, Apr 11, 2008 at 2:49 PM, Magnus Hagander <magnus(at)hagander(dot)net> wrote:
> Andrew Chernow wrote:
> > I noticed several months ago, and came across it again today, that
> > libpq's pthread-win32.c implementation is using CreateMutex rather
> > than CRITICAL_SECTION. CreateMutex is like a semaphore in that it is
> > designed to be accessible via name system-wide. Even when you don't
> > give it a name, thus bound to process that created it, it still
> > carries significant overhead compared to using win32
> > CRITICAL_SECTIONs.
> >
> > The attached patch replaces the win32 mutex calls with critical
> > section calls. The change will not affect the behavior of the
> > windows pthread_xxx functions.
>
> First of all, I like this in general :-) But a couple of comments.
>
> It changes the behavior when the pointer passed in is invalid from
> crash to silent working, right? This shouldn't actually matter,
> since these functions are only ever supposed to run from callers
> *inside libpq*, so it probalby doesn't matter...

I noticed you conjured up a ecpg threading patch sometime around early
2007. You used a mutex there deliberately because that's what libpq
did. Maybe that patch should be adjusted?

merlin