  We revisit the calculation of holographic correlation functions in IIB
supergravity on $AdS_5\times S^5$. Results for four-point functions simplify
drastically when expressed in Mellin space. We conjecture a compact formula for
the four-point functions of one-half BPS single-trace operators of arbitrary
weight. Our methods rely on general consistency conditions and eschew detailed
knowledge of the supergravity effective action.
