UUIDs in CouchDB

Question

I am wondering about the format UUIDs are by default represented in CouchDB. While the RFC 4122 describes UUIDs like 550e8400-e29b-11d4-a716-446655440000, CouchDB u

Answer 1

K I can provide some 2019 reference from the doc site: "it's in any case preferable to provide one's own uuids" -- https://docs.couchdb.org/en/latest/best-practices/documents.html?highlight=uuid

I ran slap bang into this because the (hobby) db I'm attempting as a first programming anything, deals with an application that does generate and use 4122 -compliant uuids and I was chewing my nails worrying about stripping the "-" bits out and putting them back on retrieval.

Before it hit me that the uuid that couchdb uses as the doc _id is a string not a number... doh. So I use the app's uuid generated when it creates an object to _id the document. No random duplicated uuids.

Answer 2

Technically we don't use the rfc standard for uuids as you've noticed. Version four uuids reserve something like four bits to specify the version of uuid. We also don't format them with the hyphens that are generally seen in other implementations.

CouchDB uuids are 16 random bytes formatted as hex. Roughly speaking that's a v4 uuid but not rfc compliant.

Regardless of the specifics, there's really not much of an issue in practice. You generally shouldn't try to interpret a uuid unless you're trying to do some sort out-of-band analysis. CouchDB will never interpret uuids, we only rely on the properties of randomness involved therein.

Bottom line would be to not worry about it and just treat them as strings after generation.