6.2.1 Dynamic cache service
The biggest performance gains for an application are found when data can be held ready for use or even where business logic or page rendering simply does not need to be done.
The dynamic cache service (dynacache) within the WAS stores dynamically generated web pages.
You tell WAS...
- Which pages can be cached
- Under what conditions
- For how long it is valid to cache it
The dynamic cache service is not restricted to just web content. The dynamic cache service has a number of APIs that can be used in a variety of ways for separate parts of an enterprise Java application.
Web content Provide cachespec.xml in a web module to cache dynamic content such as servlets, JSPs, JSFs, portlets, and AJAXs. This option does not require code change.
Web services You can cache web service responses based on varying data in SOAP headers and parameters. This option does not require code change to use dynamic caching.
Java objects Applications can use the DistributedMap API to cache data. Java commands Cache the output of business logic methods. After the API has been implemented, the cache can be configured and tuned with the cachespec.xml file in the same way as the web content.
Cache replication copies data between application servers. It is configurable as to how much data is replicated, from cache invalidations to replicating all cache content.
Cache invalidation management is available through automatic time-based, memory-based invalidation, programmatic or manual invalidation through the cache monitor, and specifying URLs that can invalidate a cache entry.
Use disk offload for when cache more data than can be contained in the application server JVM.
Dynamically generated content is stored in an instance of the dynamic cache called a servlet cache.
Java objects are stored in instances of the dynamic cache called an object cache.
Cache instances can be created and managed under the Resources section of the administrative console.
By default, all cached data is stored in the cache instance created by default, called baseCache.