Re: Performance degradation in commit ac1d794

On Sat, Mar 19, 2016 at 12:14 PM, Andres Freund <andres(at)anarazel(dot)de> wrote:
>
>
>
> On March 18, 2016 11:32:53 PM PDT, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>
wrote:
> >On Sat, Mar 19, 2016 at 12:00 AM, Andres Freund <andres(at)anarazel(dot)de>
> >wrote:
> >>
> >> On 2016-03-18 20:14:07 +0530, Amit Kapila wrote:
> >>
> >> > I have done some
> >> > tests on Windows with 0003 patch which includes running the
> >regressions
> >> > (vcregress check) and it passes. Will look into it tomorrow once
> >again
> >and
> >> > share if I find anything wrong with it, but feel to proceed if you
> >want.
> >>
> >> Thanks for the testing thus far! Let's see what the buildfarm has to
> >> say.
> >>
> >
> >Won't the new code needs to ensure that ResetEvent(latchevent) should
> >get
> >called in case WaitForMultipleObjects() comes out when both
> >pgwin32_signal_event and latchevent are signalled at the same time?
>
> WaitForMultiple only reports the readiness of on event at a time, no?
>

I don't think so, please read link [1] with a focus on below paragraph
which states how it reports the readiness or signaled state when multiple
objects become signaled.

"When *bWaitAll* is *FALSE*, this function checks the handles in the array
in order starting with index 0, until one of the objects is signaled. If
multiple objects become signaled, the function returns the index of the
first handle in the array whose object was signaled."

[1] -
https://msdn.microsoft.com/en-us/library/windows/desktop/ms687025(v=vs.85).aspx

With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com