Databases such as Cassandra are made so that updating doesn't actually delete the old data until some time later so frequent updates will degrade performance and storage. Other databases that allow for immediate overwriting the data will cause fragmentation and thus performance decline and wasted storage until you compact (basically recreating the entire database) which is not something you want to do all the time, especially on SSDs.
1. GDPR gives you 40 days to respond. You don’t have to run VACUUM everyday.
2. The entire point of my post was acknowledging that there are costs to being GDPR compliant, and why it’s responsible to have that cost.
If it takes a week to garbage collect that's fine, it just can't stick around forever.
Maybe a percentage will be better educated, and actually request data deletion here and there, sometimes but I don't thing anything is going to massively change in general customer behavior. The GDPR just gives the means to those who really want to control their data (which were there before, by the way, just not really enforced. Now that there's a number figure to the possible fine, now is everyone paying attention.)
The pessimistic case sounds like trying to remove things within hours.
It isn't an impossible problem to solve, but the GDPR is a significant time and a money burden that will especially be an issue for small startups that don't have millions in venture funding to spend on this.
But on the topic in general, could someone explain to me what the real world consequences are likely to be for a small business not based in the EU, of not complying? If I've never cared where my users were as long as their payments cleared (oh, is that where they get you? the payment processor?), and I'm selling handcrafted bobbins online in Canada without letting people delete their email address, what is likely to happen if someone complains to EU authorities?