Sam Mason <sam@samason.me.uk> writes:
> On Thu, Nov 15, 2007 at 06:08:20PM +0100, Reg Me Please wrote:
>> But then why allowing the LIMIT and the OFFSET as coming from function
>> argument evaluations?
> I believe the query is planned by ignoring the LIMIT and OFFSET.
No, it still knows there will be a LIMIT in effect, but it has to guess
at how tight the limit is. From memory I think it assumes 10% of the
total rows will be retrieved, which is a compromise to try to avoid
being spectacularly bad for either small or large limits.
regards, tom lane