window function count(*) and limit

Hi.

I have been puzzled about the evaluation order when using window
functions and limit.

jk=# select * from testtable; id | value
----+-------  1 |     1  2 |     2  3 |     3  4 |     4  5 |     5  6 |     6  7 |     7  8 |     8  9 |     9 10 |
10
(10 rows)

jk=# select id,count(*) over () from testtable where id < 9 limit 3; id | count
----+-------  1 |     8  2 |     8  3 |     8
(3 rows)


So the first element "id" is definately picked after the "limit 3", whereas
the window function is applied before. I have been digging in the
documentation but I didnt find this case specified out.

This behaviour may be correct, but it hugely surprises me...
I expected it to either count to 3 or blow up and tell me that count(*)
wasn't a window function.

It looks like something about the type of the function where
count(*) is a "agg" and row_number() is a "window". But shouldn't
count(*) exist as a type "window" and behave accordingly?

Same goes on for min() max() and other standard aggregates.

.. postgresql 8.4.4 (but couldn't find anyting mentioned in 8.4.5/9.0 
release notes about this).

Jesper

-- 
Jesper