Re: Simple postgresql.conf wizard

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.

regards, tom lane