[takeda]

Just a note about using uuid as a primary key. Typically you will use a b-tree index, which likes to keep things sorted. So something like a serial number works best, because it is already sorted and will be appended at the end. Otherwise inserting a new column will cause traversal the b-tree all over the place which will hurt performance it you do a lot of inserts.

If you really want to use uuid and care about performance you might prefix it with something that's increasing like a date, or perhaps (did not try it) use hash index (need to be PG 10+).

[zawerf]

(We're getting way off topic) but I think the problem with auto increment is that it can't be sharded easily since multiple shards can increment to the same value. If you then try to go back to random ids you're now stuck with 8 bytes which will conflict once every billion items or so. I guess it's pretty extreme premature optimization but I think UUID is nicer for future-proofing at the cost of some performance. (I would love to see benchmarks to know exactly how much performance I am giving up though)

By the way uuidv1 is already prefixed by a timestamp! But unfortunately it doesn't use a sortable version of the time so it doesn't work for clustering the ids into the same page. I think it was really designed for distributed systems where you would want evenly distributed ids anyway.

[takeda]

> I would love to see benchmarks to know exactly how much performance I am giving up though

https://www.youtube.com/watch?v=xrMbzHdPLKM

It ends up being a pitch for Aurora at the end (as with any presentation from AWS folks), but it has tons of useful information for standard Postgres.

[pas]

In MySQL/MariaDB/Percona InnoDB Galera every writeable replica has an auto increment offset.

[takeda]

Same in postgres[1], and I'm willing to guess every relational database has a way to do it.

[1] https://www.postgresql.org/docs/current/sql-createsequence.h...