Hashids.java VS uuid7

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.

Snowflake does not support UUID 7. What you could do is import UUID7 Python module and implement a Python UDF.

To summarise the differences:

* UUIDv6 - sortable, with a layout matching UUIDv1 for backward compatibility, except the time chunks have been reordered so the uuid sorts chronologically

* UUIDv7 - sortable, based on nanoseconds since the Unix epoch. Simpler layout than UUIDv6 and more flexibility about the number of bits allocated to the time part versus sequence and randomness. The nice aspect here is the uuids sort chronologically even when created by systems using different numbers of time bits.

* UUIDv8 - more flexibility for layout. Should only be used if UUIDv6/7 aren't suitable. Which of course makes them specific to that one application which knows how to encode/decode them.

UUIDv7 is thus the better choice in general.

(I recently wrote Python and C# implementations - https://github.com/stevesimmons/uuid7 and https://github.com/stevesimmons/uuid7-csharp)