Hashids.java VS ksuid

You basically want Hashids but sequential? Why not simple convert a base 10 (0-9) number to hex? (0-F)

I found hashids [1] to be a great compromise between integer ids in the database and copyable non-enumerable strings on the client.

[1] https://hashids.org/

I wonder how this might compare to just storing regular autoincrementing ints in the database, and converting to/from hashids (https://hashids.org/) at the edge. It eliminates the collision concern and stores more compactly at the cost of a tiny amount of encode/decode when processing requests. You’d want to push it down as close to the database layer as possible to avoid inadvertent int ID leaks; I added native hashids support to clickhouse but I’m not sure what other database support might entail.

Since hashids are not really hashes and are not secure at all this is not even achieved. Hashids can be easily decoded without the salt by a simple brute-force attack described by the authors of hashid themselves right on their website: https://hashids.org/

You don't necessarily need to use UUIDs. You could use something like Hashids to generate random strings from your sequential IDs in a reversible way, so that users can't predict what their values will be, but you can decode them as needed.

You should not use UUIDv4 as a primary key. You can use normal int values and then use hashids to make them safe for URL. UUIDv7 might be good to use as well once they are more widely supported as well.

OP here - we avoid sequences in all but one part of our application due to a dependency. We use [KSUIDs][1] and UUID v4 in various places. This one "gotcha" applies to any sequence, so it's worth calling out as general advice when running a migration like this.

[1]: https://segment.com/blog/a-brief-history-of-the-uuid/

UUID v4 isn't large enough to prevent collisions, that is why segment.io created https://github.com/segmentio/ksuid which is 160bit vs the 128bit of a UUIDv4.

Assuming you don't need to use UUIDv7 (or any UUID's) then https://github.com/segmentio/ksuid provides a much bigger keyspace. You could just append a string prefix if you wanted to namespace, but the chance of collisions of a KSUID is many times smaller than a UUID of any version.

KSUID's are have temporal-lexicographical order plus 128 bits of entropy, which is more than UUIDv4.

https://github.com/segmentio/ksuid

That's why you use ksuid (https://segment.com/blog/a-brief-history-of-the-uuid/) or, if you're willing to go with a draft spec you could go with the new UUID formats https://www.ietf.org/archive/id/draft-ietf-uuidrev-rfc4122bi...

Interesting in more history of UUIDs? Twilio Segment's blog has an amazing history lesson about how they came to be.

I use the ksuid from segment. https://github.com/segmentio/ksuid