If there is a god and that god is the one that is in the bible, then yes he would be truly sadistic. I could give you at least 20 reasons to support the fact that this god from the bible is sadistic but I only need to give one to prove my point.
If there is a god, and he truly knows everything, then he creates at least some people whose entire existence will be one of torture and never ending pain and torment. Those who will be damned to hell will be cast into an everlasting fire where they will be burned and tortured for all eternity.
So why would God create this person? If this God truly knew everything then he would know what would become of that poor soul before he ever gave it life. The only explanation for doing so would be that he is sadistic.