Yes you're missing several obvious things. Even saving the last changed date (nevermind every change date or what the change was) for every setting for every user would be earth crushingly wasteful. The value by itself isn't even worth including in backups.

Storing the last changed date for every single person on earth (even though not every person is an OpenAI customer) is something you could easily do on a laptop. It would be a rounding error for OpenAI.

I don't know what format they use for storage, but Iceberg would be a reasonable choice. A date in iceberg format is 4 bytes[1]. I checked postgres as well as a reference point. It also uses 4 bytes for a date, so whatever they use it's going to be about that.

Current world population is just shy of 8.3 Billion people [2].

4 bytes times 8.3 billion people gives 30.92 GiB. [3] OpenAI's training data will be in the petabyte range at least.

[1] https://iceberg.apache.org/spec/#schema-evolution

[2] https://worldpopulationreview.com/ and elsewhere, say census.gov if you want a US source https://www.census.gov/popclock/world

[3] https://www.wolframalpha.com/input?i=4+bytes+*+8.3+billion+i...