1.7. JBoss Data Grid Cache Architecture
Figure 1.1. JBoss Data Grid Cache Architecture
JBoss Data Grid's cache infrastructure depicts the individual elements and their interaction with each other. For user understanding, the cache architecture diagram is separated into two parts:
- Elements that a user cannot directly interact with (depicted within a dark box), which includes the Cache, Cache Manager, Level 1 Cache, Persistent Store Interfaces and the Persistent Store.
- Elements that a user can interact directly with (depicted within a white box), which includes Cache Interfaces and the Application.
Cache Architecture Elements
JBoss Data Grid's cache architecture includes the following elements:
- The Persistent Store permanently stores cache instances and entries.
- JBoss Data Grid offers two Persistent Store Interfaces to access the persistent store. Persistent store interfaces can be either:
- A cache loader is a read only interface that provides a connection to a persistent data store. A cache loader can locate and retrieve data from cache instances and from the persistent store.
- A cache store extends the cache loader functionality to include write capabilities by exposing methods that allow the cache loader to load and store states.
- The Level 1 Cache (or L1 Cache) stores remote cache entries after they are initially accessed, preventing unnecessary remote fetch operations for each subsequent use of the same entries.
- The Cache Manager is the primary mechanism used to retrieve a Cache instance in JBoss Data Grid, and can be used as a starting point for using the Cache.
- The Cache stores cache instances retrieved by a Cache Manager.
- Cache Interfaces use protocols such as Memcached and Hot Rod, or REST to interface with the cache. For details about the remote interfaces, refer to the Developer Guide.
- Memcached is a distributed memory object caching system used to store key-values in-memory. The Memcached caching system defines a text based, client-server caching protocol called the Memcached protocol.
- Hot Rod is a binary TCP client-server protocol used in JBoss Data Grid. It was created to overcome deficiencies in other client/server protocols, such as Memcached. Hot Rod enables clients to do smart routing of requests in partitioned or distributed JBoss Data Grid server clusters.
- The REST protocol eliminates the need for tightly coupled client libraries and bindings. The REST API introduces an overhead, and requires a REST client or custom code to understand and create REST calls.
- An application allows the user to interact with the cache via a cache interface. Browsers are a common example of such end-user applications.
