Martijn van Oosterhout <kleptog@svana.org> writes:
> On Fri, Mar 07, 2008 at 07:25:25PM +0100, Peter Eisentraut wrote:
>> What's the problem with setting it to ten million if I have ten million values
>> in the table and I am prepared to spend the resources to maintain those
>> statistics?
> That it'll probably take 10 million seconds to calculate the plans
> using it? I think Tom pointed there are a few places that are O(n^2)
> the number entries...
I'm not wedded to the number 1000 in particular --- obviously that's
just a round number. But it would be good to see some performance tests
with larger settings before deciding that we don't need a limit.
IIRC, egjoinsel is one of the weak spots, so tests involving planning of
joins between two tables with large MCV lists would be a good place to
start.
regards, tom lane