Re: Simple postgresql.conf wizard

"Robert Haas" <robertmhaas@gmail.com> writes:

> ANALYZE with default_statistics_target set to 10 takes 13 s.  With
> 100, 92 s.  With 1000, 289 s.

That is interesting. It would also be interesting to total up the time it
takes to run EXPLAIN (without ANALYZE) for a large number of queries.

I did start looking at running the experiment Tom was asking for with DBT3
data sets but, uh, the most recent dbt-3 data generation source I could find
was four years old. Is there an active source repository for this stuff?

> Given the amount of clamor for a higher value for
> default_statistics_target, I'm a little surprised by these results.
> It may be that the queries I'm running are not ones for which more
> statistics generate better plans, but I think they really are
> representative of what we run.  Maybe someone could suggest some types
> of query that would be likely to helped by better statistics?

I think there are a lot of variables here. One is the distribution of the
data. Your data sounds like it's reasonably evenly distributed.

--  Gregory Stark EnterpriseDB          http://www.enterprisedb.com Ask me about EnterpriseDB's 24x7 Postgres support!