Prepare Topping: Put the dry cake mix in a bowl and add the softened butter only. Blend with the mixer until a texture of small pebbles is obtained. Not too long, or it will become a dough ball.
Spread the pie filling in the bottom of a 9x12 pan. Distribute the drained pineapple across the pie filling and then the pecans. Distribute the topping evenly across the top of the mixture. It will cover the top completely.
Bake at 350° for 45-50 minutes, until golden brown.