Thiemo Kellner <thiemo@gelassene-pferde.biz> writes:
> I consider using uuid as primary key type. The documentation of
> uuid-ossp states
> (https://www.postgresql.org/docs/10/static/uuid-ossp.html#idm46428633607040)
> makes a note to consider the pgcrypto function instead but not why.
> Can somebody shed some light on that matter?
I believe the point of the recommendation is that if you only need type-4
UUIDs, you can get that from pgcrypto without needing the external
dependency of the OSSP UUID library. This is a bit less urgent than when
that text was written, because now we also support building that contrib
module against some other implementations; but there are still going to
be systems on which installing uuid-ossp is inconvenient.
There may also be a belief that pgcrypto's result is more
cryptographically secure, though I wouldn't swear to that.
regards, tom lane