Part of the challenge is that you must purchase not only Oracle, but also any and all hardware and consulting services that the Oracle Corporation sees fit to prescribe for you. Even if the challenge is winnable, it seems unlikely that the one million dollar prize will be enough to recoup your costs. It goes without saying, of course, that you will never be compensated for the time and energy you spend. It is a bad idea to look at this "contest" as a way to make a quick million.
In any case, raw speed is hardly the only reason to choose a database.