Cached Values

Tiered Cache

This library uses a tiered cache system, utilizing both the local cache as well as a caching server running the release candidate of AppFabric. Some data is stored in just the local cache, some stored in just the caching server, and some data is cached in both locations. The decision of where objects will be cached is based on frequency of use and overall size of the data.

The following data is stored only in the local cache:

LOCALLY CACHED VALUES
TYPE	CLASS	DURATION (minutes)
Browse of a user's private folder		1 minute
Browse of a user's public folder		2 minutes
Information about a user's public folder		2 minutes
Item-level full text search	List<string>	5 minutes
Search fields		15 minutes
Templates (for online submittal and editing)		30 minutes
Project Items (default values for new items)		15 minutes
Information about the ALL item aggregation		15 minutes

The following data is stored only in the remote cache due to the possible size of the data and required persistence:

REMOTELY CACHED VALUES
TYPE	CLASS
Browse of items in an aggregation (NEW or ALL)
Search of items in an aggregation

The following data is stored in the remote cache for persistence, but also is cached in the local cache for the duration of one minute to speed up overall response time. When the value in the local cache expires, the value from the remote cache is retrieved and will once again be cached locally for one minute, until no longer needed.

The number of these items is also limited, to avoid overloading the local cache. If the number of locally cached objects of a type already exceeds the limit, then the item is not locally cached and will be pulled from the remote cache each time it is needed to fulfill a request. If the number of locally cached objects of the type drops below the limit in the future, and the object is retrieved from the network cache, then it will once again be cached locally for one minute.

DOUBLY CACHED VALUES
TYPE	CLASS	LOCAL LIMIT
Information about an item		10 instances
Information about an item aggregation		10 instances
HTML skins which control overall appearance		5 instances

If there is no caching server, or it is disabled, all objects are cached in the local cache. In that case, the values which are usually doubly cached continue to cache for one minute locally. The search and browse results are locally cached for five minutes.

Cache Management

The cached values are managed by the class. This class, in turn, uses the class to maintain a list of all keys added to the caching server and for putting and retrieving items to the caching server.