BUG #3677: ceil/floor not working as expected

The following bug has been logged online:

Bug reference:      3677
Logged by:          Aleksander Machniak
Email address:      alec@alec.pl
PostgreSQL version: 8.2.4
Operating system:   linux
Description:        ceil/floor not working as expected
Details:

ceil(0.4) != ceil(4/10)

It's confusing. Ceil(4/10::numeric) is ok, but in mysql I don't need keep
casting in mind in this case.