My (second hand) understanding is that Oracle licenses by the physical core at the hypervisor level, even if you provision less to the VM. This is why HDS touts their ability with UCP to provision dedicated cores to an LPAR (not sure if they use that term) so that the hypervisor only has as many cores as you need to provision.
And who needs that stress when you have Amazon RDS or Aurora. Oracle are kinda struggling too. Dynamic DB, scaling to fit use, on a pay-per-load basis? No, Oracle is now dinosaur.
Or, if you require columnar, redshift.
I was in a meeting with SAP and you could see the uncomfortable going against redshift. You pay, but only what you use.
Disclosure: I don’t work for amazon, I’m just some tech guy.