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From Knut Anders Hatlen <Knut.Hat...@Sun.COM>
Subject Re: Fwd: Lock-free HashMap
Date Thu, 17 May 2007 07:28:23 GMT
David Van Couvering <david@vancouvering.com> writes:

> Something that may be of interest to Derby as well...

Thanks for the link, David! It looks interesting. Derby already uses
ConcurrentHashMap in the lock manager, so it should be relatively easy
to plug in a lock-free HashMap instead, I think. I'll see if I can find
time to test it out.

What would be really interesting would be if we could rewrite more of
the globally shared HashMaps in Derby (buffer manager and transaction
table come to mind) to use ConcurrentMap and provide a mechanism to
enable users to choose which implementation to use. By default, Derby
would use ConcurrentHashMap which is part of the JDK, and with a
property the users could specify that they wanted Cliff's
implementation (or someone else's).

> ---------- Forwarded message ----------
> From: Craig L Russell <Craig.Russell@sun.com>
> Date: May 16, 2007 9:21 PM
> Subject: Fwd: Lock-free HashMap
> To: open-jpa-dev@incubator.apache.org
> Don't know if anyone caught Cliff's preso at Java One...
> Anyone want to take a look at the new HashMap?
> Craig
> Begin forwarded message:
>> From: Kin-man Chung
>> Date: May 15, 2007 11:24:38 AM PDT
>> Subject: Lock-free HashMap
>> Cliff Click talked about his lock-free HashMap at JavaOne, and
>> demonstrated its superior scalability over ConcurrentHashMap.
>> The source is available at
>>   http://sourceforge.net/projects/high-scale-lib
>> We should check this out and see if it can be used in Glassfish to
>> boost the spec numbers.
>>   -Kin-man
> Craig Russell
> Architect, Sun Java Enterprise System http://java.sun.com/products/jdo
> 408 276-5638 mailto:Craig.Russell@sun.com
> P.S. A good JDO? O, Gasp!

Knut Anders

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