Tuple, table, database object identifiers size

I have installed a postgres in a SunOS 5.8 sparc SUNW,Sun-Blade-1000. By
default when i create a table of the form (int4, int4) which is the
average tuple size except of the theoretical 4+4 =8 bytes of data
size, including all the object identifiers that I suppose that are
included? Namely which default object identifiers are included in each
tuple and consequently to each table, database storage. Thank you!



                                                 SWTHRHS TOYRTOYNHS
                                                (tourtoun@csd.uch.gr)