Hello gain,
We use PB to retrieve the query results from the database. Immediately
after we do lock read on the queried object(s):
tx.lock(obj, Transaction.READ);
Is this not the correct manner to use PB+ODMG to achieve the expected
isolation-level?
Thanks,
Luis Cruz
On Tue, 2004-02-17 at 17:29, Larry Streepy wrote:
> Are you using the PB api or ODMG? My understanding is that real locking and
> isolation level support is not part of the PB api (only optimistic locking).
> The ODMG api provides the full support for record level locking.
>
> Beyond that, I haven't worked with record-level locking in OJB.
>
> Larry.
>
> > -----Original Message-----
> > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
> > Sent: Tuesday, February 17, 2004 8:45 AM
> > To: [EMAIL PROTECTED]
> > Subject: Problem using OJB's isolation level.
> >
> >
> > Hello,
> >
> > We've currently encountered a bug in our application related to the
> > isolation of
> > objects between different transaction running on the same JVM, and we fear
> > the
> > bug is originating from OJB. A detailed scenario follows:
> >
> > We are using OJB RC5 and have isolation-level set to serializable.
> > We are using ObjectCacheOSCacheImpl as the object cache (but we got the
> > same
> > results with ObjectCacheDefaultImpl).
> >
> > We launch two threads on the same JVM.
> > Thread 1 starts Transaction1 (Tx1).
> > Thread 2 starts Transaction2 (Tx2).
> > Thread 1 reads Object A (and locks it for read) using Tx1.
> > Thread 1 locks Object A for write using Tx1.
> > Thread 1 alters Object A.
> > Thread 2 reads Object A (and locks it for read) using Tx2.
> > Thread 1 confirms Tx1.
> > Thread 2 confirms Tx2.
> >
> > Is this behaviour expected? According to the lock manganer documentation
> > this
> > should not be possible. Is anyone having similar problems? Or are we using
> > OJB
> > incorrectly?
> >
> > Not sure this is relevante, but we're using the SequenceManagerHighLowImpl
> > sequence-manager and all our class/table mappings use optimistic locking:
> > <field-descriptor
> > name="ackOptLock"
> > column="ACK_OPT_LOCK"
> > jdbc-type="INTEGER"
> > locking="true"
> > />
> >
> > Any help is greatly apriciated.
> >
> > Thanks in advance,
> > Luis Cruz
> >
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>
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