[infinispan-dev] infinispan and affinity

[Galder Zamarreno]

----- "Mircea Markus" <mircea.markus at jboss.com> wrote:

> Adding isp dev in the reply.
>  
> On 3 Jun 2010, at 00:06, Romain Manni-Bucau wrote:
> 
> > Hi,
> > 
> > I would like to use infinispan (for data griding) with gridgain (for
> grid computing). My problem is to use the same "key" to run job where
> datas are located.
> > 
> > I read your article about affinity but i don't understand 2 things
> :
> > how to use it when infinispan is configured with hibernate as L2
> cache ?
> Galder might help on this - what we need to know is how do we get a
> reference to the cache used as L2 in Hibernate.

Clients do not get access to underlying Infinispan cache instance and DIST is not really a recommended mode for an L2 cache. What's your use case?

> > how to use it correctly : a) i create a key K (generated) to be sure
> to keep my date on a node, b) if i do : put(K, value),  i have to keep
> a map with my own key (understandable) to use generated key so i have
> a second "cache"
> Your scenario is a bit out of the scope of KeyAffinityService and will
> be implemented with https://jira.jboss.org/browse/ISPN-359
> An example use case for KAS is for web sessions: when you create a
> session id (you don't have to enforce a certain value on the session)
> you do want to create it so that it maps (distribution wise) on the
> local node. This way next calls from client (which uses session
> affinity) are local (at least as long as the cluster doesn't change
> its topology, but are optimists :) ).
> Now returning to your example,   you can use an replicated cache for
> keeping the mapping (myMap in your example). This would have the
> drawback of one additional remote call at creation time - but all
> subsequent gets will be local, so if the read/write ratio is high
> (many reads on the same key) this will pay off.
> More, please be aware that a topology change will cause the existing
> collocated objects to be redistributed  across nodes - even if you
> resurrect a  failed node still applies.
> HTH,
> Mircea
> > ex : 
> > K = service.getKeyForAddress(...);
> > myMap.put("myHumanKey", K);
> > cache.put(K, value);
> > readValue = cache.get(myMap.get("myHumanKey"));
> > 
> > BUT
> > i have to put myMap in the cache to be able to read it on all nodes
> ...
> > 
> > So as you can see i don't understand something so if you can help
> me. I can go on irc i you prefer, give me an hour (i'm in france).
> > 
> > Regards,
> > 
> > Romain Manni-Bucau
> 
> 
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