[hibernate-dev] Question about Hibernate 4.0 Infinispan second level cache usage...

[Galder Zamarreño]

On Aug 16, 2011, at 4:26 PM, Sanne Grinovero wrote:

> Hi Scott,
> demanding people to configure a new cache for each application is very
> tricky because of ISPN-658, unless you're referring to creating a
> whole new instance of Infinispan, with a dedicated new CacheManager
> and either starting a new JGroups channel or using the JGroups
> multiplexer Paul had written. In case of the multiplexer I'm not sure
> if the channel identifiers could be assigned dynamically according to
> application deployments and at the same time be consistent with the
> identifier numbers chosen on other application server instances, where
> different applications might be deployed or in different order, so my
> guess is that people would need to deal with additional JGroups
> configurations and handle the burden of extra network ports to be
> configured and managed.

Just to remind everyone about a previous discussion related to ISPN-658 and 2LC use case which has an impact on this.

Even though currently entities are stored in caches named using the entity name (or region name if configured), a few months back we decided that we''d move to store all entities under the same cache. However, I'm not sure this will end up happening if we can finally get a proper workaround for ISPN-658 in place, i.e. https://issues.jboss.org/browse/ISPN-1324

> 
> Using a rich key containing also the PU and application name seems the
> best option to me, and I wouldn't worry too much about the additional
> payload as that needs to be transferred anyway: I don't see how the
> receiving side could route the command to the proper application
> otherwise.

With my previous comment in mind, Sanne's suggestion here looks fine. It's about building the cache region names, which currently become actual cache names, correclly, taking the PU and app name into account.

If if the future we end up putting all entities under the same cache, the region name will become the key in the cache, as opposed to the cache name.

> 
> I think it would be nice - if possible - to not change the
> regionfactory contract but in some way wrap the keys normally
> produced, to keep it simple and avoid the payload for those cases it's
> not deployed in AS7.
> 
> Sanne
> 
> 
> 2011/8/16 Scott Marlow <smarlow at redhat.com>:
>> I'm looking at o.h.c.i.InfinispanRegionFactory and wondering how best to
>> configure the 2lc for AS 7.1.  After a recent forum discussion and
>> opening AS7-1544, I need to make some corrections to properly
>> accommodate multiple JPA persistence units sharing the same underlying
>> cache definition or having their own.
>> 
>> Currently, with AS 7.0/7.0.1, I think each application should have its
>> own Infinispan cache definition.  In theory, the same cache definition
>> could be shared if entity class names are unique across all persistence
>> units (within apps and across different applications).  This can be
>> accommodated currently by adding additional Infinispan configuration
>> entries to the AS7 standalone.xml (or domain.xml).
>> 
>> One question that I have, is could we add an additional key for
>> identifying the 2lc cache.  The additional key that I have at the time
>> of creating the container managed entity manager, is the "application
>> name scoped persistence unit name" (includes the PU name and the
>> application/containing jar name).  Perhaps that could be passed into
>> InfinispanRegionFactory via a property representing a unique way to
>> refer to all 2lc entries for a specific applications persistence unit
>> definition.  I'm not sure how desirable it would be to further qualify
>> the cache entries with this additional information (especially if it
>> increases the payload transferred during replication).
>> 
>> I think the alternative would be to have each application, configure
>> their own cache definition (either to share with all applications PU or
>> create a separate definition per PU).  This might be close to what I
>> already described as a workaround in the
>> http://community.jboss.org/message/620903 forum post.
>> 
>> What do you think?
>> 
>> Scott
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>> 
> 
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--
Galder Zamarreño
Sr. Software Engineer
Infinispan, JBoss Cache