[eclipselink-users] Object retention issues.

["Nathan Bryant" <nathan.bryant@xxxxxxxxxxxxx>]

Hi,

 

I’m seeing some object retention issues. This is in 2.1.0RC4

 

I have a large batch task that includes an aggregation task (pseudocode)

 

for (x : some CursoredStream) {

                Map<Key,Y> m

                Commit every 10K {

                                K k = new Key(x.someColumns)

                                Z z = new Z(x); persist(z); // z has a @ManyToOne field referencing X

                                Y y = m.get(k) or new Y if null

                                y.amt += x.amt

                }

}

 

The problem seems to be that multiple units of work arise from the “commit every 10K” logic, and can retain references to many clones of Xs; when in reality the Xs are not being modified and shouldn’t need to remain referenced. I am working to remove container-managed references from X to other objects that may have been created in other units of work, because it seems like this may be enough to cause the other UnitOfWork’s to fail to be gc’d. Is  there anything else I need to do to avoid this entirely? Should I consider writing native SQL to load the Xs?

 

Note that all objects are retrieved from the same EntityManager.

 

This is also somewhat unpredictable: most of the time, the memory usage does not grow too much, but sometimes it’s enough to cause problems.