Do you really need a UUID/GUID?

Postgres has a native UUID type (I don't know the details of its storage representation, though). Using MySQL by choice in 2015 is a bit of a design smell, though.

> This means the column that carries the value must at least be 36 characters (VARCHAR(36)). When you consider the text encoding (e.g. MySQL character set) used to represent strings, this could mean 2-3 bytes per character (if using UTF-8).

Ummm, this is just wrong. The UTF-8 representations of [0-9A-Ba-b] are all single bytes.