For and edge caching node, it doesn't need to. The vast majority of traffic is for a relatively small subset of the catalog that is popular that week/day/hour.

For and edge caching node, it doesn't need to. The vast majority of traffic is for a relatively small subset of the catalog that is popular that week/day/hour. Cache misses are directed to more centralized nodes that do have the full catalog (though not necessarily all on one server).