Re: Speed up Clog Access by increasing CLOG buffers

On 2016-03-23 12:33:22 +0530, Amit Kapila wrote:
> On Wed, Mar 23, 2016 at 12:26 PM, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>
> wrote:
> >
> > On Tue, Mar 22, 2016 at 4:22 PM, Andres Freund <andres(at)anarazel(dot)de> wrote:
> > >
> > >
> > > I think it's worthwhile to create a benchmark that does something like
> > > BEGIN;SELECT ... FOR UPDATE; SELECT pg_sleep(random_time);
> > > INSERT;COMMIT; you'd find that if random is a bit larger (say 20-200ms,
> > > completely realistic values for network RTT + application computation),
> > > the success rate of group updates shrinks noticeably.
> > >
> >
> > Will do some tests based on above test and share results.
> >
>
> Forgot to mention that the effect of patch is better visible with unlogged
> tables, so will do the test with those and request you to use same if you
> yourself is also planning to perform some tests.

I'm playing around with SELECT txid_current(); right now - that should
be about the most specific load for setting clog bits.

Andres