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From Daniel John Debrunner <...@apache.org>
Subject Re: Releasing latches when waiting for locks. When and why?
Date Mon, 27 Nov 2006 21:47:06 GMT
Knut Anders Hatlen wrote:
> Mike Matrigali <mikem_app@sbcglobal.net> writes:
> 
>> One approach would be to continue to support the latching in the
>> lockmanager, but to provide an alternate implementation using the
>> same interfaces (or new interfaces if necessary).  Then make the
>> default module implementation be the new improved one, but if a
>> deadlock is suspected run under the existing lockmanager with
>> all the exising nobs/reporting for deadlock and timeout.
> 
> That's an excellent idea! I think it's possible to do this without
> creating a new module. We could for instance have a property which
> told SinglePool.latchObject() whether or not it should go through the
> lock table. I will investigate how this could be done and possibly
> come up with a new patch for DERBY-2107.

I'm not so sure. If it's simpler to keep page latching at the page 
level, then it would be better to remove the added complexity from the 
lock manager. What's the current state of IDEs/debuggers tracking down 
java synchronization deadlocks? Seems a better place to solve the problem.

Dan.


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