Re: comma vs cross join question

On Fri, 2011-04-08 at 14:45 -0400, Tom Lane wrote:
> Jason Long <mailing(dot)lists(at)octgsoftware(dot)com> writes:
> > I am using 9.0.3 and the only setting I have changed is
> > geqo_effort = 10
>
> > One of the joins is a view join.
>
> Ah. The explain shows there are actually nine base tables in that
> query, which is more than the default join_collapse_limit. Try cranking
> up both join_collapse_limit and from_collapse_limit to 10 or so.
> (I'm not sure offhand if from_collapse_limit affects this case, but it
> might.)
>
> regards, tom lane

I have to say I love this mailing list and thank you Tom for your
expertise.

I played with the settings with the following results.

Worked like a charm
from_collapse_limit = 10
join_collapse_limit = 10

Worked like a charm
from_collapse_limit = 10
join_collapse_limit = 8

Failed
from_collapse_limit = 8
join_collapse_limit = 10

It looks like from_collapse_limit was the key.

I am going to leave them both at 10.