Chapter 25 Managing Persistent Component State

Storage components

A storage component read and writes component state information from a remote database server or replicates state information to other servers for in-memory stateful failover. If your component uses automatic persistence, Java serialization, or component-managed persistence with an implementation that delegates to EAServer's built-in storage component, you must specify the storage component used to interact with the persistent data store. The storage component uses the connection cache and database table identified on the Persistence/General subtab in the Component Properties dialog box.

The storage component options are:

CtsComponents/JdbcStorage Uses a JDBC connection cache to provide persistent storage of component state. This component has the Requires transaction attribute. The component's state is saved in the context of any existing transaction associated with the component.
CtsComponents/JdbcStorageReqNew A copy of the CtsComponents/JDBCStorage component that has the RequiresNew transaction attribute. The component's state is saved using a separate transaction from that used to manage any database work performed by the component.
CtsComponents/HeapStorage For stateful components only, not for entity components. Supports in-memory failover using a mirror-pair model to replicate state between pairs of servers. Additional configuration is required, as described in "Requirements for in-memory stateful failover".
A custom storage component A custom storage component, specified as package/component, where package and component are the package and component names, respectively, as displayed in Jaguar Manager. The package must be installed on all servers where your component is installed.

Customers and partners can implement custom storage components. The component must implement the CtsComponents::Storage interface and must have the Bind Object option enabled on the Instances tab. Due to the thread-safe instance requirement for the Bind Object option, only C++ and Java are suitable for coding storage components.