Re: Replication Syatem

We have tried fillfactor for indices and it seems to work.
Need to try fillfactor for table. May for that reason the bulk update
queries don't get the advantage of HOT
:)

On Wed, Apr 30, 2008 at 9:45 PM, Pavan Deolasee <pavan(dot)deolasee(at)gmail(dot)com>
wrote:

> On Wed, Apr 30, 2008 at 8:16 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> > "Pavan Deolasee" <pavan(dot)deolasee(at)gmail(dot)com> writes:
> > > That's weird. With that fillfactor, you should have a very high
> > > percentage of HOT update ratio. It could be a very special case that
> > > we might be looking at.
> >
> > He's testing
> >
>
> It's "She" :-)
>
> Oh yes. Apologies if I sounded harsh; did not mean that. I was just
> completely confused why she is not seeing the HOT updates.
>
> > >> update table1 set delta1 = 100 where code/1000000 =999;
> >
> > so all the rows being updated fall into a contiguous range of "code"
> > values. If the table was loaded in such a way that those rows were
> > also physically contiguous, then the updates would be localized and
> > would very soon run out of freespace on those pages.
> >
>
> Yeah, that seems like the pattern. I tested with the similar layout
> and a fill factor 80. The initial few bulk updates had comparatively
> less HOT updates (somewhere 20-25%), But within 4-5 iterations of
> updating the same set of rows, HOT updates were 90-95%. That's because
> after few iterations (and because of non-HOT updates) the tuples get
> scattered in various blocks, thus improving chances of HOT updates.
>
> I guess the reason probably is that she is using fill factor for
> indexes and not heap, but she hasn't yet confirmed.
>
> Thanks,
> Pavan
>
> --
> Pavan Deolasee
> EnterpriseDB http://www.enterprisedb.com
>

--
Regards
Gauri