Comment 1 Dyego Carmo 2015-04-01 19:47:35 EDT

in my persistence.xml i disabled the cache:

<persistence-unit name="xxx-ejbPU" transaction-type="JTA">
    <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
    <jta-data-source>jdbc/xxxx</jta-data-source>
    <exclude-unlisted-classes>false</exclude-unlisted-classes>
    <shared-cache-mode>NONE</shared-cache-mode> 
    <validation-mode>NONE</validation-mode>
    <properties>
      <property name="javax.persistence.validation.group.pre-persist" value="javax.validation.groups.Default"/>
      <property name="javax.persistence.validation.group.pre-update" value="javax.validation.groups.Default"/>
      <property name="eclipselink.logging.level.sql" value="FINE"/>
      <property name="eclipselink.logging.parameters" value="true"/> 
      <property name="eclipselink.multitenant.tenants-share-cache" value="false"/>
      <property name="eclipselink.multitenant.tenants-share-emf" value="false"/>
      <property name="eclipselink.target-database" value="MySQL"/>
      <property name="eclipselink.cache.shared.default" value="false"/> 
    </properties>
  </persistence-unit>

Comment 2 Dyego Carmo 2015-04-01 19:51:47 EDT

one more detail, glassfish stops by OutOfmemory error

Comment 3 Dyego Carmo 2015-04-01 20:49:25 EDT

One more info:

i not set tenant.code in persistence.xml

EVERY EntityManager.createQuery i set the tenant.code manually like this:

EntityManager em = getEntityInternalManager();
em.setProperty("tenant.code", idTenacidade);
Query qr = em.createQuery....





If I disable support for multi tenant the bug disappears....

Comment 4 Dyego Carmo 2015-04-02 19:56:43 EDT

This is very important blocker issue for MultiTenant Users

Comment 5 Dyego Carmo 2015-04-05 19:03:27 EDT

*** Bug 461873 has been marked as a duplicate of this bug. ***

Comment 6 Dyego Carmo 2015-04-05 19:03:44 EDT

*** Bug 463089 has been marked as a duplicate of this bug. ***

Comment 7 Dyego Carmo 2015-04-08 12:49:31 EDT

Hello ?

Comment 8 Dyego Carmo 2015-04-24 15:22:42 EDT

In 2.6.0 ocurs too.

Comment 9 Roque Possamai 2016-05-23 17:00:02 EDT

I'm facing a similar problem in my project.
We have a multitenant app with MultitenantTableDiscriminator by schema. Sometimes, after some use of the application, we catch this error. See this stack:

(...)
java.util.ConcurrentModificationException
 	at java.util.HashMap$HashIterator.nextNode(HashMap.java:1429)
 	at java.util.HashMap$KeyIterator.next(HashMap.java:1453)
 	at org.eclipse.persistence.descriptors.ClassDescriptor.notifyReferencingDescriptorsOfIsolation(ClassDescriptor.java:3952)
 	at org.eclipse.persistence.descriptors.CachePolicy.postInitialize(CachePolicy.java:192)
 	at org.eclipse.persistence.descriptors.ClassDescriptor.postInitialize(ClassDescriptor.java:3940)
 	at org.eclipse.persistence.internal.sessions.AbstractSession.updateTablePerTenantDescriptors(AbstractSession.java:1454)
(...)

This is similar at your previous issue <a href='https://bugs.eclipse.org/bugs/show_bug.cgi?id=463089'>463089</a> (that was closed now).

Don't you think that sincronyzing the field "ClassDescritor.referencingClasses" should resolve this problem?
The real question is, could we sincronyze this part of the code?

The modified code should look like this in "ClassDescritor.java":

    public void notifyReferencingDescriptorsOfIsolation(AbstractSession session) {
        //Must be sincronyzed to avoid ConcurrentModificationException on the referencingClasses
        synchronized(this.referencingClasses) { //THIS IS NEW!
            for (ClassDescriptor descriptor : this.referencingClasses) {
                if (descriptor.getCachePolicy().getCacheIsolation() == null || descriptor.getCachePolicy().getCacheIsolation() == CacheIsolationType.SHARED) {
                    descriptor.getCachePolicy().setCacheIsolation(CacheIsolationType.PROTECTED);
                    descriptor.getCachePolicy().postInitialize(descriptor, session);
                    for (DatabaseMapping mapping : descriptor.getMappings()) {
                        if (mapping.isAggregateMapping() && (mapping.getReferenceDescriptor() != null)) {
                            mapping.getReferenceDescriptor().getCachePolicy().setCacheIsolation(CacheIsolationType.PROTECTED);
                        }
                    }
                }
            }
        } //NEW
    }

Comment 10 Pieter van Onselen 2016-08-05 05:11:21 EDT

We have the same problem with MultiTenant setup with Eclipselink 2.6.3

Any progress on this issue

Comment 11 Valentin Iancu 2017-06-27 08:17:22 EDT

Created attachment 269072 [details]
Patch for the ConcurrentException

Fixed the issues (against 2.6 branch) - mainly ClassDescriptor clone&synchronized
 ManagedTypeImpl.init 

For ManagedTypeImpl, if many threads are creating entity managers,
ConcurrentModificationException related to members appears (the second
thread reaches the if (null != this.members) and exits - it will access
members that are in construction, leading to exceptions and invalid
results.

All the tenant client session will clone the classdescriptor from the
client session (same client session). If there are multiple tenant
client sessions started, the notifyReferencingDescriptorsOfIsolation is
called for other entity manager, while referencedDescriptors are added
from the initialize method.

The tests were done with a multitenant & rich data model with 100 parallel
threads doing create an EntityManager (with tenant id), start a
transaction, commit the transaction.

Comment 12 Valentin Iancu 2017-06-27 08:23:56 EDT

Created attachment 269073 [details]
Patch for the ConcurrentException

Re-attached the patch with less new line issues.

Comment 13 Lukas Jungmann 2017-07-25 18:02:53 EDT

Can some test-case be added to this, please? Or at least some detailed description of the setup and entities for which this can be reproduced?
Thanks!

Comment 14 Raul Mederos 2017-11-20 13:54:27 EST

Hello,
I'm having the same problem, I downloaded the 2.6.5 version, but the problem is still there. Do you know if the updated version was checked into the repository?

Thanks!!

Comment 15 Eclipse Webmaster 2022-06-09 10:33:21 EDT

The Eclipselink project has moved to Github: https://github.com/eclipse-ee4j/eclipselink