Re: increasing collapse_limits? - Mailing list pgsql-hackers

Pavel Stehule <pavel.stehule@gmail.com> writes:
> Actually we had to solve a issue with slow SELECT. The problem was in
> low value of JOIN_COLLAPSE_LIMITS. Can we increase a default of this
> value. I checked some complex query, and planner needed about 200ms
> for JOIN_COLLAPSE_LIMIT = 16. So some around 12 can be well.

I'd like to see a rather larger survey of cases before changing that.
Also, amount of memory consumed is at least as large a concern here
as runtime.
        regards, tom lane