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Re: [eclipselink-dev] FYI: uow.discoverUnregisteredNewObjectsisinefficient and with side effect

No, its a bit backwards. This is in keeping the same overall behavior that if you remove an object from a privately owned relationship it would be deleted. The problem was that if A->B and both are new objects, calling persist on A will immediately cascade persist to B. In native code, this is the same as calling register explicitly on both A and B. If you null out the relationship to B, it will still be inserted into the database. This change will now correctly prevent the B in this situation from being persisted - if the reference to it should have caused it to be deleted.

Sebastien Tardif wrote:
Let say before this feature I removed an item from a private collection,
but forgot to set to null other(s) reference to the item.
In my next unit of work, when I query and EclipseLink do not find the
object that the stale reference point to, it put a null in it.

So with this new feature, when I remove an item from a private
collection, and still have somewhere another reference to the item, no
delete will occur to DB.

Is it good understanding of the old and new functionality?

-----Original Message-----
From: christopher delahunt [mailto:christopher.delahunt@xxxxxxxxxx] Sent: Thursday, May 21, 2009 9:31 AM
To: Dev mailing list for Eclipse Persistence Services; Sebastien Tardif
Subject: Re: [eclipselink-dev] FYI:
uow.discoverUnregisteredNewObjectsisinefficient and with side effect

Hello Sebastien,

This should only affect new objects registered via a privately owned relationship. De-referencing the objects from the relationship will mean

they are removed from the cache (rather than being inserted anyway). The

wording on the method is correct, and removing it from the privateOwnedObjects only means the object is still referenced via the original privately owned relationship and so should be inserted. If it is left on the list, it is eventually unregistered. What exactly are you experiencing, and what is the relationship to the objects that are expected to be deleted?

Best Regards,

Sebastien Tardif wrote:
I just saw something bigger for side effect in discoverUnregisteredNewObjects than setUnregisteredExistingObjects.

Some of our use cases are randomly failing, and involve almost just TopLink code.

Other use case involving delete do not delete.

New code that have nothing to do with discoverUnregisteredNewObjects have been recently added to the method under revision 3676.

From the JavaDoc of method removePrivateOwnedObject that seems a good candidate for explaining our delete use case failing. The code seems to systematically remove object from privateOwnedObjects when ever it's private owned.

When an object (which is referenced) is removed from the privateOwnedObjects Map, it is no longer considered for removal from ChangeSets and the UnitOfWork identitymap.

public void iterateReferenceObjectForMapping(Object referenceObject, DatabaseMapping mapping) {

super.iterateReferenceObjectForMapping(referenceObject, mapping);

if (mapping.isCandidateForPrivateOwnedRemoval()) {

removePrivateOwnedObject(mapping, referenceObject);



public boolean isCandidateForPrivateOwnedRemoval() {

return isPrivateOwned();


public void removePrivateOwnedObject(DatabaseMapping mapping, Object privateOwnedObject) {

if (this.privateOwnedObjects != null) {

Set objectsForMapping = this.privateOwnedObjects.get(mapping);

if (objectsForMapping != null){


if (objectsForMapping.isEmpty()) {






*From:* eclipselink-dev-bounces@xxxxxxxxxxx [mailto:eclipselink-dev-bounces@xxxxxxxxxxx] *On Behalf Of *Sebastien Tardif
*Sent:* Wednesday, May 20, 2009 10:35 AM
*To:* Dev mailing list for Eclipse Persistence Services
*Subject:* RE: [eclipselink-dev] FYI: uow.discoverUnregisteredNewObjectsisinefficient and with side effect

The method getBackkupClone() has two lines doing the cloning, maybe you know for sure that these lines are never reached.

- return descriptor.getObjectBuilder().buildNewInstance();

- backupClone = descriptor.getObjectBuilder().buildNewInstance();

I still don't like the side effect of the method discoverUnregisteredNewObjects, could you provide one without side
It's kind of very useful to be able to find the list of knownNewObjects and unregisteredExistingObjects.

*From:* eclipselink-dev-bounces@xxxxxxxxxxx [mailto:eclipselink-dev-bounces@xxxxxxxxxxx] *On Behalf Of *Gordon
*Sent:* Wednesday, May 20, 2009 10:26 AM
*To:* Dev mailing list for Eclipse Persistence Services
*Subject:* Re: [eclipselink-dev] FYI: uow.discoverUnregisteredNewObjects isinefficient and with side effect

getBackupClone() does not actually build anything, it just looks for the backupClone. It is just a validation step and has not been added but moved out of the "normal" processing stream to improve performance

and efficiency.


Sebastien Tardif wrote:

FYI: uow.discoverUnregisteredNewObjects is inefficient and with side effect



* Traverse the object to find references to objects not registered in this unit of work.


*public* *void* discoverUnregisteredNewObjects(Map clones, *final* Map

knownNewObjects, *final* Map unregisteredExistingObjects, Map visitedObjects) {

The JavaDoc and signature seem to convey that the only change will be to populate the Maps passed as parameters.

* *

*The inefficiency is that in revision 2794 this line has been added:*

* *

getBackupClone(object, getCurrentDescriptor());

We see that we ignore the return value, and we can guess that building

a clone is not the cheaper operation.

Method discoverUnregisteredNewObjects end-up modifying the UOW by doing this:
The list of unregisteredExistingObjects will be returned anyway, so that doesn't seem to be the responsibility of discoverUnregisteredNewObjects to apply some logic with the result.

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