Re: Re: [COMMITTERS] pgsql: Rewrite GEQO`s gimme_tree function so that it always finds a

Robert Haas <robertmhaas@gmail.com> writes:
> On Tue, Dec 1, 2009 at 11:39 AM, Greg Sabino Mullane <greg@turnstep.com> wrote:
>> What about 14? Could we at least raise it to 14? 1/2 :)

> I doubt we can raise it at all without lying to ourselves about the
> likely results of so doing.  The GEQO planning times are in the low
> double digits of milliseconds.  My apps typically have a budget of at
> most ~200 ms to plan and execute the query, and I'm not always
> operating on empty tables.

The reason this is a configurable parameter is so that people can tune
it to their own needs.  I think the current default fits all right with
our usual policy of being conservative about hardware requirements.

			regards, tom lane