  We calculate the contribution from the $q \bar q g$ state production to the
diffractive cross sections in deep inelastic scattering at high energy. The
obtained cross section is finite by itself, and consists a part of the full
next-to-leading order result for the diffractive structure functions. Our
calculation for the diffractive structure functions is performed using exact
kinematics, under the shockwave approximation of the scattering process. Once
the calculation is completed, we show that the previously known behaviour at
the high-$Q^2$ and large-$M_X^2$ regime can be extracted from our results by
taking the appropriate limits. Furthermore, we discuss the steps required to
obtain the complete next-to-leading order results for the structure functions
in the color glass condensate (CGC) formalism, and the application of these
results to phenomenology.
