Microsoft recently acquired Citus Data. Citus is an innovative open-source extension to PostgreSQL that transforms PostgreSQL into a distributed database, dramatically increasing performance and scale for application developers. Citus has a few different products. Citus Community which is an open source extension to PostgreSQL. Citus Cloud is a fully-managed database as a service. Last but not least is Citus Enterprise which allows you to distribute your database across multiple nodes.
I personally have used the Citus extension cstore_fdw for a while now and it's a great extension for PostgreSQL. One of the databases I manage is a 2TB data warehouse type database for a telecommunications company. I pull in various records related to phone calls. After an ELT process, I store the data are tables that are partitioned daily. Today's data is stored in a normal ProgreSQL table, but all tables (partitions) for prior days are converted to a columnar store using the Citus extension cstore_fdw. It's fast and the data takes up considerably less space on disk compared to traditional PostgreSQL table storage. We are stroring around 450MM rows per month and able to scan this amount of data in 30-45 seconds.
Microsoft is really pushing into the non-Windows related products. They also appear to have a desire to really support the open source community. Microsoft started to support a managed database service for PostgreSQL on Azure in March 2018. It's pretty clear that Citus Cloud will move from AWS to Azure sometime in the future.