Read-Through

1. The Pattern

The application only ever talks to the cache. On a miss, the cache itself fetches the data from the database, stores a copy, and returns it. The fetching logic lives in one place: inside the cache layer, not scattered through your code.

Recall how cache-aside ended. Check-fetch-set-return boilerplate sat in every data-access function. Write paths that forgot their chores created a whole bug class. Read-through is that lesson's helper function, promoted to a pattern. The application asks the cache, always