The flow of a viscous compressible heat-conducting fluid in a plane channel with rigid oscillating walls is considered. It is shown that even a vanishingly small compressibility can be the reason for the onset of a resonance, i.e., sharp increase in the amplitude of oscillations of the flow parameters at a properly selected wall oscillation frequency. An exact analytical expression for the leading resonant frequency is given. Numerical calculations have demonstrated the possibility of a cumulative effect, namely, sharp increase in the mass flow rate even at constant pressure gradient.