Network Deployment (Distributed operating systems), v8.0 > Reference > Tune tips
JPA system properties
In addition to the settings that are accessible from the admin console, you can set Java Persistence API (JPA) system properties using command-line scripting.
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 admin console.
com.ibm.websphere.jpa.entitymanager.poolcapacity
Use this property to specify the default pool capacity for all JPA EntityManager instances on a server.
Data type Integer Range 0 to 500 Default 10 There is a separate pool of EntityManager instances for every persistence context reference that is 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. Although the JPA specification supports pooling of EntityManager instances, some JPA providers might not support the pooling. By default, pooling of EntityManager instances is only enabled for the JPA providers supplied with WAS. The default pool capacity is 10.
When this property is enabled, EntityManager pooling is enabled for all JPA providers. If a JPA provider stops functioning normally when this property is enabled, disable the property and contact the JPA provider for support.
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 consumed memory.
Configure OpenJPA caching to improve performance