Right now CrateDB has ..
What other databases are doing:
- postgres: In postgres 18, uuid4() (RFC), uuid7(rfc), gen_random_uuid() (uuid4 RFC)[^1]
- tinybird: generateUUIDv4() (RFC) and clickhouse[^2]
- cockroachdb: gen_random_uuid, uuid_v4 (RFC) and unique_rowid (timebased sortable)[^3]
- singlestore: UUID4 (RFC)[^4]
- firebase: UUID4, custom token (timebased sortable)[^5]
- elasticsearch: elasticflake (like us), k-ordered (timebased sortable)