Firstly, out-of-the-box OpenJPA does not provide an integration with Tangosol
cache. OPenJPA, however, does provide a flexible/pluggable mechanism for L2
cache of your choice. Out-of-the-box OpenJPA provides a concrete
implementation which can target a particular entity to a named partition of
L2 cache.
But Kodo (which was the parent and now a child of OpenJPA) does provide
other L2 cache plug-ins including Tangosol. Your supplied configuration
suggests that you have access to Kodo.
But even with Kodo, currently, there is no mechanism to cache entities in
different named partitions of Tangosols cache. All the cached entities go to
a single Tangosol cache though name of that cache can be configured.
However, because of plug-in architecture of OpenJPA/Kodo, it is relatively
inexpensive to extend the behavior you are seeking i.e. targeting entities
to different named partitions of a Tangosol cache. This extension is helped
by the provision of OpenJPA that carries name of the target L2 cache
partition in its internal representation of Class metadata (see
ClassMetaData.getDataCacheName()).
Frederic_Bellier wrote:
>
> I guess I am sending the email to this list becuase some people working on
> openjpa are making statement on the web - podcast - etc... that they have
> done for openjpa a great integration with Tangosol cache. I think his name
> is David Linskey or something like that - anyhow it does not matter...
>
> In any case - I am just trying to understand what is possible and what is
> not with openjpa as it relates to L2 cache.
>
> I think Tangosol plug in for openjpa is totally different - they are
> promoting the use of Tangosol first with a backing map that uses openjpa
> for the persistence to the DB. The problem with their approach is that I
> am
> loosing all the benift of the openjpa O/R mapping and relationship
> management in particular.
> So I am using the opnejpa approach first - which means the L2 cache is on
> the side. And I believe I am only using openjpa code - meaning the
> persistence xml defines the following:
> <property name="kodo.DataCache"
> value="tangosol(TangosolCacheName=a,TangosolCacheType=named,ClearOnClose=false)"/>
> This - I believe - is a regular openjpa functionality. Isn't it?
>
> So my question is why when I specify the data cache annotation - openjpa
> does not honor this particular cache for this particular entity?
> @DataCache(enabled = true, name =
> "tangosol(TangosolCacheName=b,TangosolCacheType=named,ClearOnClose=false)",
> timeout = -1)
>
>
> I just want to specify which L2 cache to use per entity.
> Becuase if I do it at the EntityManagerFactory - then all entities will
> have to use the same cache. Which would mean that I would need to consider
> all the data to be equal in terms of how it is used by the system - which
> of course is not correct and will remove the performance benefit of using
> an L2 cache (well most of them - some will remain - but for sure it would
> be a shame). Think about a clustered application with data being clustered
> and other being local only and you see what I mean by loosing pretty much
> all benefit from L2 cache - (welcome to serialization overhead
> nightmare...
> ;) - my performance will be terrible - plus it would be such a bad design
> for the application anyhow.
>
> The openjpa doc talks about specifying the L2 cache by name per enity via
> the DataCache annotation. I would like to understand how I can use it.
> Becuase it seems to be exactly what I need. Except that I can not make it
> work with Tangsol.
>
> I am ssuming that all entities of an object graph are stored in the L2
> cache sperately - and not as one big serialized blob for the entire graph.
> That way when I query for an object deep in my graph I would be able to
> get
> it from the cache easily. If so then I would think that assigning each
> entity to a specific cache would be trivial.
>
> BTW - in your previous email I am assuming you are refering to the
> entityManagerFactory and not the Entitymanager because the L2 cache is at
> the Factory level and not the entityManager level - otherwise obviously it
> would not be usefull at all ;) . (Your L1 cache is - and the Tx too of
> course).
>
> Frederic
>
>
>
>
>
> "Kevin Sutter"
> <[EMAIL PROTECTED]
> om> To
> [email protected]
> cc
> 03/27/2008 12:32
> PM Subject
> Re: How to set a tangosol cache per
> entity?
> Please respond to
> [EMAIL PROTECTED]
> che.org
>
>
>
>
>
>
>
> Frederic,
> I'm not an expert with the Tangosol plugin, but in general, the OpenJPA
> DataCache plugin is on a per-EntityManager basis. So, if configured, all
> Entities associated with a given PersistenceContext (EntityManager) could
> be
> cached. You then have the ability to designate certain Entities as being
> non-cached. Or, you could go in reverse and designate only those Entities
> that you do wish to cache.
>
> If your question is more specific to the Tangosol plugin, then you'll have
> to ask the development team that developed that plugin. BEA? Tangosol?
> Not sure. The OpenJPA code only supports the DataCache plugin
> capabilities
> (and the built-in DataCache implementation). The other cache plugins (ie,
> Tangosol, ObjectGrid, etc) are supported by other development
> organizations.
>
> Thanks,
> Kevin
>
> On Thu, Mar 27, 2008 at 1:00 PM, <[EMAIL PROTECTED]> wrote:
>
>>
>> I need to have a specific tangosol cache per entity - (or at least per
>> group of entity):
>>
>> I am trying to use the annotation @DataCache to make this happen -
>> unfortunately it does not work. openjpa always uses the tangosol cache
>> define din the persistence xml file - basically the default cache.
>>
>> I tried to set the @DataCache annotation to:
>> @DataCache(enabled = true, name =
>>
>>
> "tangosol(TangosolCacheName=b,TangosolCacheType=named,ClearOnClose=false)",
>> timeout = -1)
>>
>> I also tried
>> @DataCache(enabled = true, name = "b", timeout = -1)
>>
>> But none format worked. Again - all entities are currently going to the
>> default Tangosol cache.
>>
>> It is a must for our project to be able to cache our entities in specific
>> cache (We are using Tangosol). Using one cache only for all entities in
>> the
>> system almost removes all the benefit of the cache all together - and we
>> might as well not have one.
>>
>> How can I accomplish that?
>> Should I implement our own RemoteCommitProvider? (This seems complicated
>> becuase I do not know all the internal of openjpa)
>> Can I use the entity callback method to talk to the cache myself? (This
>> seems easy) - but in order to use it I need to be sure all entity
> callback
>> methods will be called even when I save a top level object in the graph -
>> I
>> mean I need all the other entities related to the parent one to have teir
>> callback fired if they get saved too.
>>
>> Please help - this is a huge issue for us.
>>
>> Thank you,
>>
>> Frederic
>>
>>
>>
>
>
>
>
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