Re: Reduce ProcArrayLock contention

On Mon, Jul 27, 2015 at 8:47 PM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>
> On Sat, Jul 25, 2015 at 12:42 AM, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>
wrote:
> > I thought that internal API will automatically take care of it,
> > example for msvc it uses _InterlockedCompareExchange64
> > which if doesn't work on 32-bit systems or is not defined, then
> > we have to use 32-bit version, but I am not certain about
> > that fact.
>
> Instead of using pg_atomic_uint64, how about using pg_atomic_uint32
> and storing the pgprocno rather than the pointer directly?
>

Good Suggestion!

I think this can work the way you are suggesting and I am working on
same. Here I have one question, do you prefer to see the code for
this optimisation be done via some LWLock interface as Pavan is
suggesting? I am not very sure if LWLock is a good interface for this
work, but surely I can encapsulate it into different functions rather than
doing everything in ProcArrayEndTransaction.

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