Re: [Windows,PATCH] Use faster, higher precision timer API

On 09/17/2014 08:27 AM, Craig Ringer wrote:
> Hi all
>
> Attached is a patch to switch 9.5 over to using the
> GetSystemTimeAsFileTime call instead of separate GetSystemTime and
> SystemTimeToFileTime calls.
>
> This patch the first step in improving PostgreSQL's support for Windows
> high(er) resolution time.
>
> In addition to requiring one less call into the platform libraries, this
> change permits capture of timestamps at up to 100ns precision, instead
> of the current 1ms limit. Unfortunately due to platform timer resolution
> limitations it will in practice only report with 1ms resolution and
> 0.1ms precision - or sometimes even as much as 15ms resolution. (If you
> want to know more, see the README for
> https://github.com/2ndQuadrant/pg_sysdatetime).
>
> On Windows 2012 and Windows 8 I'd like to use the new
> GetSystemTimePreciseAsFileTime call instead. As this requires some extra
> hoop-jumping to safely and efficiently use it without breaking support
> for older platforms I suggest that we start with just switching over to
> GetSystemTimeAsFileTime, which has been supported since Windows 2000.
> Then more precise time capture can be added in a later patch.
>
>

That will presumably breaK XP. I know XP has been declared at EOL, but
there are still a heck of a lot of such systems out there, especially in
places like ATMs, but I saw it in use recently at a US surgical facility
(which is slightly scary, although this wasn't for life-sustaining
functionality). My XP system is still actually getting some security
updates sent from Microsoft.

I'm fine with doing this - frogmouth and currawong would retire on the
buildfarm.

Just wanted to be up front about it.

cheers

andrew