Estimator EKF2 frequency

Good Morning,

I use a Pixhawk 4 with QGroundControl. The sensors used is GPS, barometer, Gyroscope and a rangefinder (MB1242).

I would like to know at wich frequency is update the output of the estimator like “altitude estimation”, “roll. pitch, yaw estimated”. The update is made at a fixed frequency or it’s irregular (a new estimation calcul is made at each new measure) ?
If it’s at fixed frequency, is the frequency the same for all regulator or no, is there a parameter in QGC ?
If the update is irregular, is there a certitude that the calcul is finished to calculate the next estimation ? Is it possible that the estimator have too many measure at the same time and the calcul can’t be performed ?

Thank you very much.