Re: Simple postgresql.conf wizard

On Thu, Nov 13, 2008 at 11:53 AM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com> writes:
>> A lot of people have suggested raising our default_statistics target,
>> and it has been rejected because there's some O(n^2) behavior in the
>> planner, and it makes ANALYZE slower, but it's not that crazy.
>
> I think everyone agrees it ought to be raised. Where the rubber meets
> the road is deciding just *what* to raise it to. We've got no
> convincing evidence in favor of any particular value.
>
> If someone actually wanted to put some effort into this, I'd suggest
> taking some reasonably complex benchmark (maybe TPCH or one of the DBT
> series) and plotting planner runtime for each query as a function of
> statistics_target, taking care to mark the breakpoints where it shifted
> to a better (or worse?) plan due to having better stats.

Almost there... I have a MSA70 plugged into the DL380 I have from HP
and I'm trying to find time to get my scripts updated to deal with how
tools have changed over the years... I'm updating the DBT-2 (tpc-c
kit) I have first

Regards,
Mark