Leszek,
> I speculate that because there would be one less column to insert/update
> it should not be worse. Not sure though what's the overhead of handling
> composite PK on INSERT/UPDATE operation.
No, it should be better. The reason one uses surrogate keys (i.e. sequence
IDs) is to simplify joins to other tables. Within the table itself,
there's no reason to use them.
--
--Josh
Josh Berkus
Aglio Database Solutions
San Francisco