Heterogeneous SQL statement batching is an improvement over the org.apache.openjpa.jdbc.kernel.BatchingConstraintUpdateManager. This functionality can improve the performance of your JPA application because it allows multiple different SQL statements to be sent to the database in a single batch. For example, if you have a transaction that updates one Entity and also inserts another Entity, when you use the BatchingConstraintUpdateManager function, two different batches are sent to the database: one for the update and another for the insert. In the same scenario, if you use the HeteroConstraintUpdateManager function, only one batch, which contains both operations, is sent to the database.
<property name="openjpa.jdbc.UpdateManager"
value="com.ibm.ws.persistence.jdbc.kernel.HeteroConstraintUpdateManager(batchLimit=250)"/>
In this example the SQL statement batch limit is set to 250.
The default batch limit is 100.