Donnie,
please see inline ...
Werner
> Werner,
>
> I put on my dba hat and thought it was a good idea that all db.load()
> operations specify Database.ReadOnly.
No, it unfortunately isn't. Objects should be loaded as readonly only if you
do not plan to modify them during the course of your current transaction.
There's some documentation on this, so please consider revisiting this.
> When I needed to change/delete an
> object that was loaded ReadOnly, I would invoke db.update() prior to
> operation.
Which, afair, would not work, as objects loaded readonly are (internally)
treated differently than the ones loaded e.g. in sahred mode.
> I assumed that castor would cache only one of the objects if
> queried ReadOnly, regardless of the number of load requests.?
Castor will ALWAYS cache one instance only, irrespective of the access mode.
>
> I have since changed a few methods around and am now allowing Castor to
> load objects based on their declaration in the mapping file
> (class="shared") or Castor default if not specified. I assume now that
> castor will cache one for each load request.?
No, if Castor has successfully loaded an object instance for which caching
is enabled, is will cache this one instance only. Why would it want to cache
one instance mnore than once ?
> A solution for delete (well one that works) to the
> ObjectNotFoundException is two fold, remove the item from the parent
> array and update() the parent.
It could well be that I have missed something here, but is this problem
again related to readonly access, or completely unrelated ?
>Case:
>
> UserTransaction 1:
> ut.begin();
> Database db = jdo.getDatabase();
> Parent parent = db.load(Parent.class, parentKeyValue);
> ut.commit();
>
> // obtain an arbitrary child element for testing
> Child child = parent.getChildArray().get(1);
>
> UserTransaction 2:
> ut.begin();
> Database db = jdo.getDatabase();
> db.update(child);
> db.delete(child);
> // custom method to remove child from parent array
> parent.removeChild(child);
> db.update(parent);
> ut.commit();
>
>
>
> On Tue, 2004-07-20 at 16:15, Werner Guttmann wrote:
> > Donnie,
> >
> > this is going to be hard to analyse as there's plenty of systems
> involved. Anyhow, before starting to dig randomly, can you please
elaborate as to
> why
> > you are using Database.ReadOnly when loading the parent object.
> >
> > Werner
> >
> > On Tue, 20 Jul 2004 11:41:14 -0500, Donnie Armstrong wrote:
> >
> > >
> > >oops, my case has a typo, it is supposed to be db.remove(child). Sorry.
> > >
> > >Also, tran2 cannot see newly created child records. Another case:
> > >
> > >UserTransaction 1:
> > >db = jdo.getDatabase();
> > >ut.begin();
> > >parentObj = db.load(parent.class, parentKeyValue, Database.ReadOnly);
> > >db.create(child);
> > >ut.commit();
> > >
> > >UserTransaction 2:
> > >db = jdo.getDatabase();
> > >ut.begin();
> > >parentObj = db.load(parent.class, parentKeyValue, Database.ReadOnly);
> > >ut.commit();
> > >
> > >User transaction 2 does not fail, but If I obtain an iterator over the
> > >array of children, I notice that my newly created child is not there.
> > >
> > >
> > >On Tue, 2004-07-20 at 10:45, Donnie Armstrong wrote:
> > >> hello,
> > >>
> > >> Using Castor CVS, Global demarcation, Oracle and JBoss 3.2.3. The JDO
> > >> handle is static, each transaction gets their own database handle.
> > >>
> > >> UserTransaction 1:
> > >> db = jdo.getDatabase()
> > >> ut.begin();
> > >> // Load parent which automatically loads the Array of children.
> > >> parentObj = db.load(parent.class, parentKeyValue, Database.ReadOnly);
> > >> db.update(child); // to sync the timestamps
> > >> db.delete(child); // remove a child
> > >> ut.commit();
> > >>
> > >> UserTransaction 2:
> > >> db = jdo.getDatabase()
> > >> ut.begin();
> > >> // Load parent which automatically loads the Array of children.
> > >> parentObj = db.load(parent.class, parentKeyValue, Database.ReadOnly);
> > >>
> > >> Castor throws an ObjectNotFoundException ... was not found in
> persistent
> > >> storage.
> > >>
> > >> I suspect that Castor retains the deleted object in it's cache, but
> why
> > >> does the latter operation in transaction 2 try to load the recently
> > >> deleted object from DB?
> > >>
> > >> The only way I've been able to recover is to shutdown container,
> which
> > >> resets Castor cache.
> > >>
> > >> Any help would be appreciated.
> > >> Donnie
> > >>
> > >>
> > >>
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> > >
> > >
> > >
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