Citus is indeed an example for "distributed PostgreS". There are also serverless Postgres (Neon, Nile, AWS Aurora) which do this. If you are interested in part

Citus is indeed an example for "distributed PostgreS". There are also serverless Postgres (Neon, Nile, AWS Aurora) which do this. If you are interested in partitioning in an OLAP scenario, this will soon be coming to pg_analytics, and some other Postgres OLAP providers like Timescale offer it already