Migrating data between two different EntityManager in a RestEasy endpoint - jpa

Question

I'm using a RestEasy endpoint to migrate data between an SQL Server database and an Oracle database. I have both datasources defined on JBoss
<?xml version="1.0" encoding="UTF-8"?>
<datasources xmlns="http://www.jboss.org/ironjacamar/schema"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.jboss.org/ironjacamar/schema http://docs.jboss.org/ironjacamar/schema/datasources_1_0.xsd">
<datasource jndi-name="java:jboss/datasources/oracleDS"
pool-name="oracle" enabled="true"
use-java-context="true">
<connection-url>jdbc:oracle:thin:#127.0.0.1:1521:XE</connection-url>
<driver>oracle</driver>
<pool>
<min-pool-size>10</min-pool-size>
<max-pool-size>100</max-pool-size>
<prefill>true</prefill>
<use-strict-min>false</use-strict-min>
<flush-strategy>FailingConnectionOnly</flush-strategy>
</pool>
<security>
<user-name>SOURCE</user-name>
<password>source</password>
</security>
</datasource>
<datasource jndi-name="java:jboss/datasources/sqlserverDS" pool-name="sqlserver"
enabled="true" use-java-context="true">
<connection-url>jdbc:sqlserver://localhost:1433;databaseName=DEST</connection-url>
<driver>sqlserver</driver>
<pool>
<min-pool-size>10</min-pool-size>
<max-pool-size>100</max-pool-size>
<prefill>true</prefill>
<use-strict-min>false</use-strict-min>
<flush-strategy>FailingConnectionOnly</flush-strategy>
</pool>
<security>
<user-name>DEST</user-name>
<password>dest</password>
</security>
</datasource>
</datasources>
My persistence.xml file
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation=" http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
<persistence-unit name="primary">
<jta-data-source>java:jboss/datasources/oracleDS</jta-data-source>
<properties>
<property name="hibernate.hbm2ddl.auto" value="none"/>
<property name="hibernate.show_sql" value="true"/>
<property name="hibernate.dialect" value="org.hibernate.dialect.Oracle10gDialect"/>
</properties>
</persistence-unit>
<persistence-unit name="secondary" transaction-type="JTA">
<jta-data-source>java:jboss/datasources/sqlserverDS</jta-data-source>
<class>com.foobar.model.sqlserver.SourceEntity</class>
<exclude-unlisted-classes>true</exclude-unlisted-classes>
<properties>
<property name="hibernate.hbm2ddl.auto" value="none"/>
<property name="hibernate.show_sql" value="true"/>
</properties>
</persistence-unit>
</persistence>
And my RestEasy endpoint
package com.foobar.rest;
import com.foobar.model.DestEntity;
import com.foobar.model.sqlserver.SourceEntity;
import java.util.List;
import javax.ejb.Stateless;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import javax.persistence.TypedQuery;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;
import org.apache.log4j.Logger;
/**
*
* #author Andres
*/
#Stateless
#Path("/endpoint")
public class FoobarEndpoint {
private static final Logger logger = Logger.getLogger(FoobarEndpoint.class);
#PersistenceContext(unitName = "primary")
private EntityManager csEm;
#PersistenceContext(unitName = "secondary")
private EntityManager vhEm;
#GET
#Path("/migration")
public Response migration() {
logger.trace("Starting migration process");
TypedQuery<SourceEntity> sourceQuery = this.vhEm.createNamedQuery("SourceEntity.findAll", SourceEntity.class);
List<SourceEntity> sourcePeriodsList = sourceQuery.getResultList();
this.csEm.createNamedQuery("DestEntity.deleteAll").executeUpdate();
int i = 0;
for (SourceEntity sourcePeriod : sourcePeriodsList) {
DestEntity entity = new DestEntity();
// Set DestEntity fields
entity = this.csEm.merge(entity);
}
return Response.noContent().build();
}
}
The problem arises after I retrieve the data from source and attempt to delete data from the destination, with JBoss giving me this error:
javax.transaction.SystemException: IJ000356: Failed to enlist: java.lang.Throwable: Unabled to enlist resource, see the previous warnings. tx=TransactionImple < ac, BasicAction: 0:ffff7f000001:-47dbad9f:53b43ae8:a38 status: ActionStatus.ABORT_ONLY >
Apparently, it attempts to do both operations in the same transaction, and since they come from different servers, it fails to do so.
Any ideas of a workaround?

Answer 1

I couldn't do it the way I wanted to. I ended up querying the source by using plain JDBC and inserting to the destination using JPA.