A bit of a shameless plug since it’s my employer, we’re super excited to go open source and make a distributed postgres available to everybody, happy to answer questions without any of the marketing speak from the blog.
Between this and the recent opening of Greenplum, the world of postgres clustering has become much richer.
Since Citus is available as a Postgres extension, could I enable it on an AWS RDS instance to get multi-core support?
Unfortunately I don’t think RDS allows you to use arbitrary extensions, given that they have a list of supported ones: http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/CHAP_PostgreSQL.html#PostgreSQL.Concepts.General.FeatureSupport
Letting users hook random binaries into the database doesn’t sound like it makes managing instances easy :)
I think the closest you can come is something like this: https://www.citusdata.com/blog/14-marco/178-scaling-out-postgresql-on-amazon-rds-using-masterless-pg-shard
There, you run the master node in AWS and keep your workers in RDS. That would give you query parallelism but the blog post uses pg_shard and it would probably take some fiddling to replicate with Citus (we likely rely on some UDFs being present on the workers)