Citus is an extension to Postgres to make it a distributed, shared-nothing DBMS.
Disk-oriented
Shared-Nothing
SQL
Relational
http://www.citusdata.com/
https://github.com/citusdata/citus
https://docs.citusdata.com/
Citus Data
TR , US
2010
Commercial, Open Source
PostgreSQL
AGPL v3