Caching concepts

WebSphere® eXtreme Scale can operate as an in-memory database processing space, which you can use to provide in-line caching for a database back-end or to serve as a side-cache. In-line caching uses eXtreme Scale as the primary means for interacting with the data. When eXtreme Scale is used as a side-cache, the back-end is used in conjunction with the eXtreme Scale. This section describes various eXtreme Scale cache concepts and scenarios and discusses the available topologies for deploying an eXtreme Scale grid.

Architecture and topology
With WebSphere eXtreme Scale, your architecture can use local in-memory data caching or distributed client-server data caching.
Local in-memory cache
In the simplest case, eXtreme Scale can be used as a local (non-distributed) in-memory data grid cache. The local case can especially benefit high-concurrency applications where multiple threads need to access and modify transient data. The data kept in a local eXtreme Scale grid can be indexed and retrieved using WebSphere eXtreme Scale's query support. The ability to query the data can help developers greatly when working with large in memory data sets versus the limited data structure support provided with the Java™ virtual machine (JVM), which is ready to use as is.
Distributed cache
WebSphere eXtreme Scale is most often used as a shared cache, to provide transactional access to data to multiple components where a traditional database would otherwise be used. The shared cache eliminates the need configure a database.
Database integration
WebSphere eXtreme Scale is used to front a traditional database and eliminate read activity that is normally pushed to the database. A coherent cache can be used with an application directly or indirectly using an object relational mapper. The coherent cache can then offload the database or backend from reads. In a slightly more complex scenario, such as transactional access to a data set where only some of the data requires traditional persistence guarantees, filtering can be used to offload even write transactions.
Java object caching concepts
WebSphere eXtreme Scale is primarily used as a data grid and cache for Java objects. You can use several APIs to interact with the eXtreme Scale grid to access and store these objects.