https://db-engines.com/en/system/PostgreSQL%3BYandex+Databas...
I think they wanted to have a DB that is better tuned to distributed systems. Still don't know, why they do an SQL like query language called YQL (what would that mean in practical terms? Could a common ORM framework like JPA deal with the YQL query language ?)
Back to looking at Couchbase, Yugabase, or Citus for my distributed SQL.
The trick is that it's better to have the extra guard rails. And all of Couchbase, Yugabase, and Citus support foreign keys even with sharding and replication, so that's not an issue when the DB supports it.
So yeah, it's on my short list. :) I've used triggers in one project recently, but that was literally the first time in five years so it's not as much of a must-have for me.