A bit of anecdata: I've joined Google 7 years ago to support an append-only very-large-scale database. About that time legal told us that an upcoming EU law wil

A bit of anecdata: I've joined Google 7 years ago to support an append-only very-large-scale database. About that time legal told us that an upcoming EU law will require selective deletion from the database. That was technically impossible and just against the design assumptions of the thing. Google spent millions of dollars to develop a solution to this conundrum over the next couple years. It was ready by the time GDPR came into force.