Re: testing HS/SR - 1 vs 2 performance

On Sat, Apr 24, 2010 at 5:17 AM, Simon Riggs <simon@2ndquadrant.com> wrote:
>> Both Heikki and I objected to that patch.
>
> Please explain your objection, based upon the patch and my explanations.

Well, we objected to the locking.  Having reread the patch a few times
though, I think I'm starting to wrap my head around it so, I don't
know, maybe it's OK.  Have you tested grabbing the ProcArrayLock in
exclusive mode instead of having a separate spinlock, to see how that
performs?

>> And apparently it doesn't
>> fix the problem, either.  So, -1 from me.
>
> There is an issue observed in Erik's later tests, but my interpretation
> of the results so far is that the sorted array patch successfully
> removes the initially reported loss of performance.

Is it possible the remaining spikes are due to fights over the spinlock?

...Robert