"Reinoud van Leeuwen" <reinoud@xs4all.nl> writes:
> I have a table that contains almost 8 milion rows. The primary key is a
> sequence, so the index should have a good distribution. Why does the
> optimizer refuse to use the index for getting the maximum value?
The optimizer has no idea that max() has anything to do with indexes.
You could try something like
select * from tab order by foo desc limit 1;
regards, tom lane