Dear internet, Today we have screwed up by applying a broken migration to the running production service and causing a massive outage for several hours… Because the rollback function was terribly broken as well. As a result, we had to restore a backup that was made several hours ago, losing some new data. Why did it happen? The easiest answer is just to say: “Because it is X’s fault! He is the author of this migration, he should learn how databases work”. But, it is counterproductive. Instead, a...