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From Kristian Waagan <Kristian.Waa...@Sun.COM>
Subject Re: Row Locking
Date Sun, 03 May 2009 10:19:41 GMT
wfalby wrote:
> My application processes events. These events are sent to registered users.
> These events can be deleted when they reach a certain age. There is a thread
> to send events to registered users and there is another thread to delete old
> events. The thread sending an event should lock it from the thread that
> deletes old events. Each thread uses its own connection to the database. In
> the sending thread, I've tried using a SELECT ... FOR UPDATE and setting the
> ResultSet.CONCUR_UPDATABLE on the prepare statement. In both cases, the
> thread that deletes events deleted the event being held by the sending
> thread. The default isolation level and autocommit options are used.
>   

Hi Walter,

If you're using the read committed isolation level, I think you need to 
use SELECT ... FOR UPDATE WITH RS.
Which behavior do you see if you do that?

I think Derby treats SELECT ... FOR UPDATE a bit differently than some 
other database systems, and I also believe there is at least one Jira 
[1] issue logged for changing the behavior.


Regards,
-- 
Kristian

[1] https://issues.apache.org/jira/browse/DERBY
> Thanks in advance...Walter
>   


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