From your experience, which database serve is more difficult to scale? MySQL or Postgres? I know MySQL has several out-of-the-box scaling/clustering features, but with Postgres there is none that comes out-of-the-box. CMIIW.

**EDIT**:

Sorry for the confusion here, my question is referring to scaling out (horizontal scaling), i.e clustering, sharding, etc. I know both can scale horizontally, but which one is easier to implement?

Thank you for sharing.