Prepositions: "upon" vs. "after"

After means just that: at any time after the event. Using after would mean that once the new dataset had been created, the conditions are right for an account to be activated.

Upon indicates a simultaneous operation, "at the time of". See ODO sense 8 (upon redirects to on):

8 indicating the day or part of a day during which an event takes place:

  reported on September 26
  on a very hot evening in July

• at the time of:
      she was booed on arriving home

The quoted sentence means

Consider the possibility of activating accounts automatically at the time of a new dataset creation.

Upon may well refer to an action leading to/triggering another one immediately.