Re: libpq Win32 Mutex performance patch

On Fri, Apr 11, 2008 at 2:49 PM, Magnus Hagander <magnus@hagander.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