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Posted to dev@openjpa.apache.org by Fr...@capgroup.com on 2008/04/03 19:36:37 UTC

QueryCache scope question

I Apologise in advance if this question seems silly to you guys.

I am asking this question in order to finish a plugin for openjpa.
This plugin needs to implement the DataCache using Coherence - so I am
thinking that I will need to implmenet the QueryCache using Coherence to
inorder to make the QueryCache common accross all the JVMs in the cluster.

So here is the question:
Is it imperative for the QueryCache to be shared across multiple JVMs?
I suppose otherwise (when data gets removed from the L2 cache for example)
- a single JVM QueryCache could return wrong information since it would not
have been updated. Is this correct?

F


OpenJPA and dynamic object like EMF

Posted by Marek Mosiewicz <ma...@jotel.com.pl>.
Is there any plan to for JPA extend support beyond standard Java classes. As 
far as I see there all metadata about persisten class use Class class. That 
mean that there is no chance to use any dynamic objects like Eclipse EFM 
(unlike you create static model for them) or Map. It would be great to 
extend OpenJPA for this.

Best regards,
        Marek Mosiewicz
        http://www.jotel.com.pl 


Re: QueryCache scope question

Posted by Patrick Linskey <pl...@gmail.com>.
>  PS: Would you guys be interested in a Coherence plugin for openjpa? I mean
>  I could contribute the code.

Definitely. However, the difficulty is that I don't really understand
how OpenJPA can compile it -- presumably we can't check the Coherence
jars into svn. IANAL, though. Maybe Cameron can chime in with a
solution?

>  We were using kodo here but run into issues - the kodo plugin was not
>  powerful enough (not was it functional really).

FYI, it should be easy to just plug in your own data and query caches
into Kodo; Kodo is essentially a layer on top of OpenJPA. So, you
should be able to just specify your data and query cache class names
(or cache manager class name) in your configuration properties.

-Patrick

On Thu, Apr 3, 2008 at 3:21 PM,  <Fr...@capgroup.com> wrote:
> Thanks a lot for the answer,
>
>  Since I am finsihng up the plug in for openjpa - I am also doing the
>  QueryCache using Coherence - which is why I asked the question.
>  We were using kodo here but run into issues - the kodo plugin was not
>  powerful enough (not was it functional really).
>
>  Anyhow - this is why we are looking at opnejpa (and hibernate as well - but
>  I like OpenJPA better for now - specially since I saw that the StroeManager
>  code was using the named cache concept properly).
>  This is why I wrote the new OpenJPA plug in for Coherence.
>
>
>  PS: Would you guys be interested in a Coherence plugin for openjpa? I mean
>  I could contribute the code.
>
>  F
>
>
>
>
>
>              "Patrick Linskey"
>              <plinskey@gmail.c
>              om>                                                        To
>                                        dev@openjpa.apache.org
>                                                                         cc
>              04/03/2008 11:44
>              AM                                                    Subject
>                                        Re: QueryCache scope question
>
>              Please respond to
>              dev@openjpa.apach
>                    e.org
>
>
>
>
>
>
>
>
>  >  Is it imperative for the QueryCache to be shared across multiple JVMs?
>  >  I suppose otherwise (when data gets removed from the L2 cache for
>  example)
>  >  - a single JVM QueryCache could return wrong information since it would
>  not
>  >  have been updated. Is this correct?
>
>  Yes, that's correct.
>
>  Note that Kodo ships with a Coherence plug-in for both data and query
>  caching.
>
>  -Patrick
>
>  On Thu, Apr 3, 2008 at 10:36 AM,  <Fr...@capgroup.com> wrote:
>  >
>  >  I Apologise in advance if this question seems silly to you guys.
>  >
>  >  I am asking this question in order to finish a plugin for openjpa.
>  >  This plugin needs to implement the DataCache using Coherence - so I am
>  >  thinking that I will need to implmenet the QueryCache using Coherence to
>  >  inorder to make the QueryCache common accross all the JVMs in the
>  cluster.
>  >
>  >  So here is the question:
>  >  Is it imperative for the QueryCache to be shared across multiple JVMs?
>  >  I suppose otherwise (when data gets removed from the L2 cache for
>  example)
>  >  - a single JVM QueryCache could return wrong information since it would
>  not
>  >  have been updated. Is this correct?
>  >
>  >  F
>  >
>  >
>
>
>
>  --
>  Patrick Linskey
>  202 669 5907
>
>
>



-- 
Patrick Linskey
202 669 5907

Re: QueryCache scope question

Posted by Fr...@capgroup.com.
Thanks a lot for the answer,

Since I am finsihng up the plug in for openjpa - I am also doing the
QueryCache using Coherence - which is why I asked the question.
We were using kodo here but run into issues - the kodo plugin was not
powerful enough (not was it functional really).

Anyhow - this is why we are looking at opnejpa (and hibernate as well - but
I like OpenJPA better for now - specially since I saw that the StroeManager
code was using the named cache concept properly).
This is why I wrote the new OpenJPA plug in for Coherence.


PS: Would you guys be interested in a Coherence plugin for openjpa? I mean
I could contribute the code.

F




                                                                           
             "Patrick Linskey"                                             
             <plinskey@gmail.c                                             
             om>                                                        To 
                                       dev@openjpa.apache.org              
                                                                        cc 
             04/03/2008 11:44                                              
             AM                                                    Subject 
                                       Re: QueryCache scope question       
                                                                           
             Please respond to                                             
             dev@openjpa.apach                                             
                   e.org                                                   
                                                                           
                                                                           




>  Is it imperative for the QueryCache to be shared across multiple JVMs?
>  I suppose otherwise (when data gets removed from the L2 cache for
example)
>  - a single JVM QueryCache could return wrong information since it would
not
>  have been updated. Is this correct?

Yes, that's correct.

Note that Kodo ships with a Coherence plug-in for both data and query
caching.

-Patrick

On Thu, Apr 3, 2008 at 10:36 AM,  <Fr...@capgroup.com> wrote:
>
>  I Apologise in advance if this question seems silly to you guys.
>
>  I am asking this question in order to finish a plugin for openjpa.
>  This plugin needs to implement the DataCache using Coherence - so I am
>  thinking that I will need to implmenet the QueryCache using Coherence to
>  inorder to make the QueryCache common accross all the JVMs in the
cluster.
>
>  So here is the question:
>  Is it imperative for the QueryCache to be shared across multiple JVMs?
>  I suppose otherwise (when data gets removed from the L2 cache for
example)
>  - a single JVM QueryCache could return wrong information since it would
not
>  have been updated. Is this correct?
>
>  F
>
>



--
Patrick Linskey
202 669 5907



Re: QueryCache scope question

Posted by Patrick Linskey <pl...@gmail.com>.
>  Is it imperative for the QueryCache to be shared across multiple JVMs?
>  I suppose otherwise (when data gets removed from the L2 cache for example)
>  - a single JVM QueryCache could return wrong information since it would not
>  have been updated. Is this correct?

Yes, that's correct.

Note that Kodo ships with a Coherence plug-in for both data and query caching.

-Patrick

On Thu, Apr 3, 2008 at 10:36 AM,  <Fr...@capgroup.com> wrote:
>
>  I Apologise in advance if this question seems silly to you guys.
>
>  I am asking this question in order to finish a plugin for openjpa.
>  This plugin needs to implement the DataCache using Coherence - so I am
>  thinking that I will need to implmenet the QueryCache using Coherence to
>  inorder to make the QueryCache common accross all the JVMs in the cluster.
>
>  So here is the question:
>  Is it imperative for the QueryCache to be shared across multiple JVMs?
>  I suppose otherwise (when data gets removed from the L2 cache for example)
>  - a single JVM QueryCache could return wrong information since it would not
>  have been updated. Is this correct?
>
>  F
>
>



-- 
Patrick Linskey
202 669 5907