3.1 Cache-Aside (Lazy Loading)

An application that keeps a cache beside its database, checks the cache first on every read, and loads an entry only when the read misses is using cache-aside, also called lazy loading. It is the most widely used caching pattern because it is simple. The application code decides what goes into the cache and when it comes out. The cache never talks to the database, and the database never knows the cache exists, so if the cache disappears the system still works, only more slowly.