Craig,
We needed to switch to List (ArrayList) for the transactional cache
(i.e. a separate list of changed instances vs. HashMap of key to instance
for the lookups).
thanks,
-marina
Craig L Russell wrote:
> Hi Scott,
>
> I'm curious. Can you reproduce this on CMP 2.1? I recall that we had to
> fix some issues in this area, and it took a bit of time to get it right.
>
> Craig
>
> On Mar 3, 2006, at 3:46 PM, Scott Oaks wrote:
>
>> Given an entity A and a session bean that executes this code:
>>
>> Query q = em.findNamedQuery("findAllA");
>> List l = q.getResultList();
>> Object[] arr = l.toArray();
>> Arrays.sort(arr); --> sort by Primary Key of A
>> for (int i = 0; i < arr.length; i++)
>> ((A)a[i]).setFoo(some value);
>>
>> When the transaction of the session bean ends, a flurry of update
>> statements will be committed to the database. The problem is that these
>> update statements are not executed in order. Hence if two threads
>> simultaneously execute this code, one of them will get a deadlock
>> exception, despite the careful sorting of the operations in the
>> application.
>>
>> How is this deadlock to be avoided?
>>
>> -Scott
>
>
> Craig Russell
> Architect, Sun Java Enterprise System http://java.sun.com/products/jdo
> 408 276-5638 mailto:Craig.Russell_at_sun.com
> P.S. A good JDO? O, Gasp!
>