Especially an immutable database (like Git's index) sounds like a very powerful concept. No more need for modification dates (they would be in the change record

Especially an immutable database (like Git's index) sounds like a very powerful concept. No more need for modification dates (they would be in the change record) and no need at all for separate log tables and all that guff. Every CRUD system ends up with some sort of audit log tacked on, costing heaps in terms of both maintenance, storage and extra processing for every change. In addition I would want there to be a command analogous to `vacuum` to truncate this history while the database is online, similar to Git's rebase or filter-branch.