Hi,
I work at a complex web application that use EJB and Hibernate on JBoss. I use singleton EntityManagerFactory, and share it between all running process using Entity Manager instance.
The problem occurs when in a struct action is called an update on entity, and before action ends another process read and update same object.
I have that second process (it's a web service called from third-parts) read an old value and not the updated one in the action.
I know that data become persistent on database only after action end its work and control come back to user. Unfortunately this action after Entity Manager merge execution, it must call a web service that sometimes return after 10s . Meanwhile other process have wrong value if read this object.
I need that merge in first process become instantly persistent, or, I need that other process read right value.
I don't know if the second level cache is working and has effect in this scenario.
A solution is to make an update using JDBC instead Hibernate, but I would like a clean solution to do it.
a brief outline
t0 = start action ;t1= action find and merge entity; t2= start call to web service; t6= web service return; tend = end action ;
t3= start second process ; t4= find and merge entity; t5=end second process
t0 t1 t2 t3 t4 t5 t6 tend
|---------------|-------|------------------------------|-------|
|-----|----|
I need that at t3 the value read is that one merged at t2.
This is my persistence.xml
Code:
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="1.0" 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_1_0.xsd">
<persistence-unit name="VisiaIntegrazione_EJB" transaction-type="JTA">
<provider>org.hibernate.ejb.HibernatePersistence</provider>
<jta-data-source>java:/ds/VisiaIntegrazioneDS</jta-data-source>
<class>.....entity.ApplicationServer</class>
....
<class>.....entity.Devices</class>
<exclude-unlisted-classes>false</exclude-unlisted-classes>
<properties>
<property name="hibernate.dialect" value="org.hibernate.dialect.MySQLInnoDBDialect"/>
<!-- Caching properties -->
<property name="hibernate.cache.use_second_level_cache" value="true"/>
<!--<property name="hibernate.cache.provider_class" value="net.sf.ehcache.hibernate.SingletonEhCacheProvider" />-->
<property name="net.sf.ehcache.configurationResourceName" value="ehcache.xml"/>
<!--<property name="hibernate.cache.provider_class" value="org.hibernate.cache.NoCacheProvider"/>-->
<!--<property name="hibernate.cache.provider_class" value="org.hibernate.cache.EhCacheProvider" />-->
<property name="hibernate.cache.use_query_cache" value="true"/>
<property name="hibernate.cache.region.factory_class" value="net.sf.ehcache.hibernate.SingletonEhCacheRegionFactory"/>
<property name="hibernate.transaction.manager_lookup_class" value="org.hibernate.transaction.JBossTransactionManagerLookup"/>
<property name="hibernate.max_fetch_depth" value="4"/>
<!-- hibernate.generate_statistics a true produce informazioni su hibernate da loggare -->
<property name="hibernate.generate_statistics" value="true"/>
</properties>
</persistence-unit>
</persistence>
this is an example of Entity Manager update
Code:
EntityManager em = EntityMan.getEMF().createEntityManager();
try {
em.find(Devices.class, device.getId());
em.merge(device);
em.flush();
} catch (Exception e) {
logger.debug(e.getMessage());
e.printStackTrace();
}
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