Distributed Cache OM : Cache Manager Options at the Entity Level

Cache Manager Options at the Entity Level
With cache-based object management and a backing store, objects created by the event processing application, can be used or kept in three locations:
You can manage where the object data is kept at the level of the entity type. The best choice depends on how often the object changes, and how often it is accessed. The various options balance the memory and performance characteristics of the system. Different applications have different priorities and it is up to you to choose the options that suit your needs.
Between Cache and Backing Store: Preloading Options and Limited Cache Size
When the system demands an object that exists in backing store but not in cache, the object is automatically loaded from the backing store into the cache, and then into the Rete network. This takes time, but reduces the need to store so much data in the cache, which uses up memory.
You can also specify what to preload into the cache from the backing store at startup.
You can remove items from cache that are not frequently needed, and use the backing store to store them.
See Understanding How Entity Objects are Managed in TIBCO BusinessEvents Administration.
Limiting Cache Size
When you use a backing store, you can limit the size of the cache by specifying the cache size. This is helpful for large volumes of data that the available memory cannot hold. When the number of objects in cache reaches the cache size limit, some of the objects are automatically evicted from cache (they are still in the backing store).
See Chapter 2, CDD Configuration Procedures in TIBCO BusinessEvents Administration.
Between Rete Network and Cache: Cache Modes
As explained above, you can store less-frequently-used objects in the backing store only, and they are retrieved into the cache as needed. In a similar way, you can keep memory objects in the cache or Rete network as follows:
These controls are known as cache modes, or simply modes, for short. They apply to individual entity types.
Cache modes allow you to define how to manage the instances of each object type. In a concurrent system, Cache Plus Memory mode is inappropriate for most objects, due to the difficulties involved in keeping all the concurrent processes synchronized. Use that mode only for constants, and concepts that change infrequently.
Small, frequently used, stateless entities can be kept in JVM memory only, for improved performance.
Most typically, Cache Only mode is used, and the objects are retrieved into memory (the Rete network) only when needed for an RTC. Locking is still required as in any concurrent system.
See Chapter 8, Cache Modes and Project Design for more details.