uuid = 128-bit int for a database. the "abc-1234-abc...." is just a representation of that int. So, if we think about it as using a int-128 or a string[~25], o

uuid = 128-bit int for a database. the "abc-1234-abc...." is just a representation of that int. So, if we think about it as using a int-128 or a string[~25], one of them takes more space than the other. So, except for taking up more space, the question then becomes, are larger keys/indexes less efficient, I would say yes. Other people can probably explain this better than me, but at least for me, it seems intuitive that going through and comparing entries in a list of small things is easier than doing it on a list of large things.