Effect of solid in equilibrium

CaCO3 (s) = CaO (s) + CO2 (g)


We know that pure solids quantity doesn't affect the position of equilibrium. But the application of pressure in gas does.


If we add CaCO3 in the closed system, the position of equilibrium should change, shouldn't it?


If we add CaCO3 the concentration shouldn't increase but the pressure in closed system should increase. Then it should affect in CO2 because the pressure has been increased. 


Then why this is told that that pure solids quantity doesn't affect the position of equilibrium? 


