Which was where Twitter had to go in their first major refactor, as well. Originally timeline views would be built on-demand, but that approach proved unscalable very quickly, so they moved to preemptively building timelines by copying tweets everywhere they needed to go at publish-time rather than request-time.

It's basically just an inversion; instead of the cache being a read-through layer over the database, the database becomes a write-through layer over the cache.