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From Craig L Russell <Craig.Russ...@Sun.COM>
Subject Re: greetings and question about data stores
Date Thu, 09 Aug 2007 01:00:13 GMT
I've created http://wiki.apache.org/jdo/ScalableBackEnd and linked it  
from the main JDO wiki.

Regards,

Craig

On Aug 7, 2007, at 10:39 AM, Richard Schilling wrote:

> Look forward to writing for the Wiki.  I'll go ahead and pull out  
> my reference material so we can have some time-proven data store  
> texts to work off of.  That will get us started.
>
> Cheers!
>
> Richard Schilling
>
> Craig L Russell wrote:
>> Sounds like there's room here for a good discussion, since JDO is  
>> the only standard datastore-agnostic API that might exploit  
>> something like MUMPS.
>> I'll set up a wiki where we can continue the dialog.
>> Craig
>> On Aug 4, 2007, at 6:33 PM, Richard Schilling wrote:
>>> I think an upgrade for FOStore is definitely feasible, but it  
>>> should be redesigned.  There's no reason I can think of why a  
>>> robust b-tree type implementation could not be managed.  The  
>>> Berkeley DB sets are O.K., but they typically work well for small  
>>> data sets.  Where we have large data sets, performance I think is  
>>> pretty degraded.
>>>
>>> Having said that, I think there's a lot to be learned from an  
>>> old, but very quick and very robust MUMPS data store.  It's  
>>> underlying structure is essentially a b-tree, and works very  
>>> well.  We could take a similar design approach.
>>>
>>> Richard Schilling
>>>
>>>
>>> Craig L Russell wrote:
>>>> Hi Richard,
>>>> If you're interested in the non-RDBMS side of JDO, I've had for  
>>>> a long time an interest in upgrading the FOStore piece to use a  
>>>> more modern key/value store like a modern version of Berkeley DB.
>>>> The sticking point for many of the non-RDBMS stores in the  
>>>> public domain is the lack of query capability. And much of this  
>>>> is due to the lack of schema for the values. In MDR, the key is  
>>>> not-quite-opaque. You can see this in the special treatment of  
>>>> keys in the FOStore key-generation. We'd have liked to use a  
>>>> simple long as a key but MDR doesn't support them. And the value  
>>>> is truly opaque. In FOStore we simply "serialize" the objects  
>>>> for storage replacing objects with true FOStore object references.
>>>> Anyway, if you're interested in upgrading FOStore to use a  
>>>> better store than MDR, perhaps we can start a wiki to discuss this.
>>>> Best,
>>>> Craig
>>>> On Aug 4, 2007, at 10:46 AM, Richard Schilling wrote:
>>>>> Looking some more this morning, I also found the source code  
>>>>> repository for netbeans b-tree implementation:
>>>>>
>>>>> http://mdr.netbeans.org/source/browse/mdr/src/org/netbeans/mdr/ 
>>>>> persistence/btreeimpl/?only_with_tag=release60_m4
>>>>>
>>>>>
>>>>> And lo and behold, I also found an old CORBA module I didn't  
>>>>> know existed.  This is going to get interesting.... :-)
>>>>>
>>>>> Richard
>>>>>
>>>>>
>>>>> Craig L Russell wrote:
>>>>>> Hi Richard,
>>>>>> Sorry about that. The FOStore implementation had just a bit of  
>>>>>> documentation which I've tried to locate for you but can't  
>>>>>> seem to find just now. When I find it I'll post it on the JDO  
>>>>>> site and put a link here.
>>>>>> Craig
>>>>>> On Aug 3, 2007, at 11:07 PM, Richard Schilling wrote:
>>>>>>> Here is the posting I had way back in March of 2006, which  
>>>>>>> didn't get much response - if any at all:
>>>>>>>
>>>>>>> http://www.webservertalk.com/archive383-2006-3-1437593.html
>>>>>>>
>>>>>>> Never did find out the answers to these questions, but this 

>>>>>>> explains what I'm up to.
>>>>>>>
>>>>>>> After just looking, I find this on the netbeans site:
>>>>>>>
>>>>>>> http://mdr.netbeans.org/architecture.html#persistence
>>>>>>>
>>>>>>> This explains MDR, the use of b-tree (which the JDO reference
 
>>>>>>> implementation uses) in much more detail than I saw in the past.
>>>>>>>
>>>>>>> FYI.
>>>>>>>
>>>>>>> Cheers!
>>>>>>>
>>>>>>> Richard Schilling
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> Craig L Russell wrote:
>>>>>>>> Hi Richard,
>>>>>>>> The fostore project at Apache JDO is an implementation that
 
>>>>>>>> you could study for insights as to how the various  
>>>>>>>> components interact. There's a separation of an abstract
 
>>>>>>>> StoreManager responsible for storing data to a specific 

>>>>>>>> datastore, a StateManager responsible for managing the state
 
>>>>>>>> of individual instances, and a PersistenceManager whose API
 
>>>>>>>> is pretty much defined in the JDO specification.
>>>>>>>> Regards,
>>>>>>>> Craig
>>>>>>>> On Jul 31, 2007, at 3:23 PM, Richard Schilling wrote:
>>>>>>>>> I did realize that the JDO API and the model in the apache
 
>>>>>>>>> code was just the implementation of the spec.  What I'm
 
>>>>>>>>> after is to make sure I understand what parts of the
API  
>>>>>>>>> (which interfaces) are used by a specific implementation
to  
>>>>>>>>> cause classes to be committed to the data store.  It
looks  
>>>>>>>>> like the transactions defined in the spec serve this
 
>>>>>>>>> purpose, but there's so much information I can't be sure.
>>>>>>>>>
>>>>>>>>> Thanks ... still getting my head around the JDO spec
- I've  
>>>>>>>>> even read the JDO book which I have.
>>>>>>>>>
>>>>>>>>> Cheers.
>>>>>>>>> Richard
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Matthew T. Adams wrote:
>>>>>>>>>> Hi Richard,
>>>>>>>>>> Apache JDO is the home of the JDO API (the interface
&  
>>>>>>>>>> class files of the
>>>>>>>>>> specification) & TCK (the code that tests whether
a JDO  
>>>>>>>>>> implementation is
>>>>>>>>>> compliant with the specification); none of the code
here  
>>>>>>>>>> actually writes to
>>>>>>>>>> a database*.  The reference implementation for JDO
2.0 is  
>>>>>>>>>> JPOX
>>>>>>>>>> (www.jpox.org) -- it is an implementation of the
JDO 2.0  
>>>>>>>>>> API.  There are
>>>>>>>>>> also many other implementations of JDO out there.
>>>>>>>>>> HTH,
>>>>>>>>>> Matthew
>>>>>>>>>> *:  There is a legacy reference implementation called
 
>>>>>>>>>> FOStore (pronounced
>>>>>>>>>> like "foster") that was used as the JDO 1.0, but
I don't  
>>>>>>>>>> think that's used
>>>>>>>>>> much anymore.  Others can comment on that.
>>>>>>>>>> -----Original Message-----
>>>>>>>>>> From: Richard Schilling  
>>>>>>>>>> [mailto:rschilling@cognitiongroup.biz] Sent: Tuesday,
July  
>>>>>>>>>> 31, 2007 10:22 AM
>>>>>>>>>> To: jdo-dev@db.apache.org
>>>>>>>>>> Subject: greetings and question about data stores
>>>>>>>>>> Greetings.  This is my first post to the list.
>>>>>>>>>> I would like to know about the code base itself.
 There is  
>>>>>>>>>> not any documentation that discusses the structure
of the  
>>>>>>>>>> code itself and how the software interacts with the
data  
>>>>>>>>>> store.
>>>>>>>>>> Can any one tell me what source code files actually
 
>>>>>>>>>> contain the code that writes to the data store?
>>>>>>>>>> Thanks!
>>>>>>>>>> Richard Schilling
>>>>>>>>>
>>>>>>>> Craig Russell
>>>>>>>> Architect, Sun Java Enterprise System http://java.sun.com/

>>>>>>>> products/jdo
>>>>>>>> 408 276-5638 mailto:Craig.Russell@sun.com
>>>>>>>> P.S. A good JDO? O, Gasp!
>>>>>>>
>>>>>> Craig Russell
>>>>>> Architect, Sun Java Enterprise System http://java.sun.com/ 
>>>>>> products/jdo
>>>>>> 408 276-5638 mailto:Craig.Russell@sun.com
>>>>>> P.S. A good JDO? O, Gasp!
>>>>>
>>>> Craig Russell
>>>> Architect, Sun Java Enterprise System http://java.sun.com/ 
>>>> products/jdo
>>>> 408 276-5638 mailto:Craig.Russell@sun.com
>>>> P.S. A good JDO? O, Gasp!
>>>
>> Craig Russell
>> Architect, Sun Java Enterprise System http://java.sun.com/products/ 
>> jdo
>> 408 276-5638 mailto:Craig.Russell@sun.com
>> P.S. A good JDO? O, Gasp!
>

Craig Russell
Architect, Sun Java Enterprise System http://java.sun.com/products/jdo
408 276-5638 mailto:Craig.Russell@sun.com
P.S. A good JDO? O, Gasp!


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