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From Charles Anthony <charles.anth...@hpdsoftware.com>
Subject RE: Distributed Lock Management
Date Tue, 07 Sep 2004 15:14:40 GMT

Funnily enough, we are using ActiveMQ for the messaging in our cluster/grid,
and have had several converations with James on IRC ! Small world. Anyway, I
just popped on, but he wasn't around. I haven't yet talked with him about
distributed locking. The networking issues aren't, surprisnly, doing my head
in - it's the locking bit.

Off the top of my head, I'm guessing each cluster member should have an
InMemoryMap - and should try and obtain locks locally and then check every
other member of the cluster.


Cheers,

Charles.

> -----Original Message-----
> From: Brian McCallister [mailto:mccallister@forthillcompany.com]
> Sent: 07 September 2004 16:13
> To: OJB Developers List
> Subject: Re: Distributed Lock Management
> 
> 
> I am looking, in the very near future, to do a simple 
> dirty-only cache 
> replication system based on ActiveMQ/ActiveCluster as well.
> 
> My plans are to simply use topic support and broadcast TextMessage 
> impls with table names and pk values of rows that need to be flushed. 
> The idea is to crank up local caching and only transmit dirty 
> changes. 
> Replicating the whole object is too expensive on a large 
> cluster. Using 
> table+pk allows non-OJB apps making changes to participate as well by 
> producing/subscribing and understanding the schema.
> 
> If you can get on IRC during the day (day meaning daytime and early 
> evening in London) James Strachan is usually available and quite 
> willing to help on irc.codehaus.org in #activemq
> 
> Having ODMG lockmap support in it would be very handy. I 
> would suggest 
> starting with activemq's built-in multicast support for local 
> networks 
> since the total size of identity+locktype should (really should!) be 
> smaller than the broadcast packet size. If you (we) need bigger 
> packets, using the jgroups support would probably be the next 
> step. The 
> reason for the multicast:// or jgroups:// is exactly that 
> single point 
> of failure problem. Both of these impls are fully peer-to-peer in 
> activemq.
> 
> -Brian
> 
> On Sep 7, 2004, at 10:35 AM, Charles Anthony wrote:
> 
> > Hi All,
> >
> > We're looking into making our application clustered. Well, 
> actually, we
> > *are* making our application clustered (using multiple 
> server processes
> > residing on multiple servers reading requests off a JMS queue). It 
> > looks
> > really rather cool.
> >
> > What we need to do now is cope with distributed ODMG locking. I 
> > realise that
> > we have the Servlet LockMap which I shall certainly look at, but I 
> > have to
> > say, I'm a little concerned about having a single point of failure 
> > (which is
> > what I think would be the case - but please correct me if 
> I'm wrong).
> >
> > I am thinking of implementing a distributed LockMap using JMS, 
> > possibly on
> > top of activecluster.codehause.org - but has anyone got any 
> pointers 
> > for me
> > for building lock managers/maps ? Other products/papers/discussions 
> > that I
> > can read up on ? Basically, from the OJB point of view, I 
> think that 
> > the
> > thing to do is to create implement a new LockMap.
> >
> > Cheers,
> >
> > Charles.
> >
> >
> > ___________________________________________________________
> > HPD Software Ltd. - Helping Business Finance Business
> > Email terms and conditions: www.hpdsoftware.com/disclaimer
> >
> >
> >
> > 
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> 
> 
> 
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