Ian Barwick <barwick(at)gmail(dot)com> writes:
> There is a little info in the FAQ:
> http://www.postgresql.org/docs/faqs/FAQ.html
> particularly sections 4.6 and 4.14
I think the calculation in section 4.6 is out of date --- it's been
awhile since row headers were 36 bytes. The more correct number is
between 24 and 32 bytes depending on whether you created the table
WITH OIDS and whether your machine requires 4- or 8-byte alignment.
regards, tom lane