Oracle has changed the way it charges users to run its software in Amazon Web Services, effectively doubling the cost along the way.

Big Red's previous licensing regime [PDF] recognised that AWS's virtual CPUs were a single thread of a core that runs two threads. Each virtual CPU therefore counted as half a core.

That's changed: Oracle's new cloud licensing policy [PDF] says an AWS vCPU is now treated as a full core if hyperthreading is not enabled. A user renting two AWS vCPUS therefore needs to pay full freight for both, effectively doubling the number of Oracle licences required to run Big Red inside AWS. And therefore doubling the cost as well.

The new policy also says: “When counting Oracle Processor license requirements in Authorized Cloud Environments, the Oracle Processor Core Factor Table is not applicable.” That table [PDF] says Xeon cores count as half a licence. Making the table inapplicable to the cloud again doubles the licence count required.

The Register learned of the change from this post by Oracle-watcher Tim Hall. Pieter Jansen, owner of Navicle, an Australian Oracle licensing consultancy, confirmed Hall's analysis and the effect on price price to El Reg.

“The unit cost does not change,” Jansen said, adding that he's yet to hear whether Oracle will grandfather previous arrangements for current users, who face larger bills if Big Red does not cut them a break.

The new policy also makes AWS and Azure equal in Oracle's eyes: the latter now needs one licence per core too.

Jansen suspects the decision was made to make Oracle's own cloud a more attractive proposition.

He may be onto something, as Oracle last year named AWS as public enemy number one in the cloud, claiming its own cloud will be cheaper and faster than the Amazonian offering. These new licensing arrangements certainly look to be taking care of the cheaper side of the deal.

The Register has asked Oracle why it has made this change and how it will treat existing customers, but was told a response would not be possible until Oracle USA opens its doors this week. We'll update this story, or write a new one, if we receive a response. ®