I don't understand why, if you want to use this, would you run it on RPi instead of just on your computer? Is it for realtime guarantees (ie. no OS updating in the background)?
while i'm currently using sqlite, since it has only one write transaction at a time, if I understand correctly, opening a tx and doing outside requests while in the transaction could potentially block your whole application if the outside requests keep timing out... so you kinda need to watch out for that