JPA system properties

In addition to the settings that are accessible from the administrative console, we can set Java Persistence API (JPA) system properties using command-line scripting.

If we are running with JPA 2.0, we can use the properties page to define the com.ibm.websphere.jpa.entitymanager.poolcapacity JPA system property. Add the system property directly to the server.xml file or as a generic Java virtual machine (JVM) argument using the administrative console.

com.ibm.websphere.jpa.entitymanager.poolcapacity

If we are running with JPA 2.0, use this property to specify the default pool capacity for all JPA EntityManager instances on a server.

EntityManager pooling is only supported for OpenJPA, the JPA 2.0 provider for WebSphere Application Server .

Information	Value
Data type	Integer
Range	0 to 500
Default	10

There is a separate pool of EntityManager instances for every persistence context reference defined in an application. A persistence context reference can be @PersistenceContext or a persistence-context XML element.

This property setting affects all pools in the application server process. Each pool uses the capacity defined by this property. The default pool capacity is 10. Increasing the integer value of this setting might improve performance by reducing the number of EntityManager instances that must be created. However, increasing the value affects the amount of memory used.