DocumentDB is a thin layer that converts the mongo commands to Postgres, uses Aurora Postgres. If you check, the constraints are exactly same. Even list RDS CLI

DocumentDB is a thin layer that converts the mongo commands to Postgres, uses Aurora Postgres. If you check, the constraints are exactly same. Even list RDS CLI returns the DocumentDB clusters. Most obvious indicator is DocumentDB is single node write whereas Mongo is really not, coming from Aurora Postgres.