1.1 About Oracle True Cache

True Cache is an in-memory, read-only cache in front of an Oracle database.

Like Oracle Active Data Guard, True Cache is a fully functional, read-only replica of the primary database, except that it's mostly diskless.

Modern applications often require a high number of connections and fast, low-latency access to the data. A popular approach is to place caches in front of the database because applications typically perform many more reads than updates, and they can read from the cache without affecting the database performance. For example, an airline reservation system reads data frequently as people shop for flights, and it's okay if the data isn't the most current compared to what's in the database. The application only needs to access the most current data when someone reserves a flight.

Unlike conventional caches, True Cache automatically keeps the most frequently accessed data in the cache, and it keeps the cache consistent with the primary database, other objects in the same cache, and other caches. It caches all Oracle Database objects and data types, including JSON.

Because True Cache implements Oracle Database security policies, you can control access to the cache. This enables you to cache sensitive data, like private personal information, that you might not ordinarily cache.