> It's helpful architecturally to have a distinction between on-disk structures (which you're careful about either not changing or migrating) and in-memory stru

> It's helpful architecturally to have a distinction between on-disk structures (which you're careful about either not changing or migrating) and in-memory structures (which don't) rather than trying to freeze or migrate everything. That's true, but syncing between the database and in memory data structures is tedious. Imagine building an application and never having to worry about storage. Just instantiate and reference objects and you're set. When working with lots of data, the OS would just swap things in on demand. That would save a lot of development time for many types of applications. But yes, there would be some big challenges regarding application updates and how not to destroy all data with a trivial bug. (A misplaced `customers = []` might be all it takes to permanently wipe all data. Perhaps this idea should be combined with immutable data structures and versioning.) [Edit] After some more consideration: what I'm talking about feels more like a language feature than something the operating system can/should do.