Re: Frequent Update Project: Design Overview of HOT Updates

Hi,

On 11/10/06, Pavan Deolasee <pavan(dot)deolasee(at)gmail(dot)com> wrote:
>
>
> On 11/10/06, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> >
> > "Pavan Deolasee" <pavan(dot)deolasee(at)gmail(dot)com> writes:
> > > On 11/10/06, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> > > (2) Isn't this full of race conditions?
> >
> > > I agree, there could be race conditions. But IMO we can handle
> > those.
> >
> > Doubtless you can prevent races by introducing a bunch of additional
> > locking. The question was really directed to how much concurrent
> > performance is left, once you get done locking it down.
> >
> >
> I understand your point and I can clearly see a chance to improve upon the
> current
> locking implementation in the prototype even though we are seeing a good
> performance
> boost for 50 clients and 50 scaling factor with pgbench runs as mentioned
> by Nikhil.
>
> Regards,
> Pavan
>

Yes, we have done a number of runs with and without autovacuum with
parameters like 50 clients, 50 scaling factor and 25000 transactions per
client. 50 clients should introduce a decent amount of concurrency. The tps
values observed with the HOT update patch (850 tps) were approximately
200+% better than PG82 sources (270).

Runs with 25 clients, 25 scaling factor and 25000 transactions produce
similar percentage increases with the HOT update patch.

Regards,
Nikhils

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