Alban Hertroys <alban@magproductions.nl> writes:
> There's practically no difference between SELECT 1 FROM ... and SELECT *
> FROM ...; the only added costs (AFAIK) are for actually fetching the
> column values and such. Pretty cheap operations.
You're both glossing over exactly the wrong thing, particularly seeing
that Rafal appears to be using 8.0 or older which hasn't got 8.1's
significant reductions in targetlist evaluation costs.
regards, tom lane