WAS v8.5 > ReferenceJPA system properties
In addition to the settings that are accessible from the dmgr console, we can set 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 server.xml or as a generic JVM argument using the dmgr console.
com.ibm.websphere.jpa.entitymanager.poolcapacity
Specify the default pool capacity for all JPA EntityManager instances on a 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. 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 WebSphere Application Server. 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.
Related
Configure OpenJPA caching to improve performance