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From "Luciano Resende" <luckbr1...@gmail.com>
Subject Re: [LDAP DAS] Efficient Updating of Persisted Objects
Date Wed, 21 Mar 2007 21:09:40 GMT
Sorry if I'm just jumping on the discussion, but I'd like to understand it a
little more. Is the idea here to have client performing LDAP operations,
using a SDO/DAS layer that can be easily switched back and forth between a
pure LDAP repository and a RDB repository ?

                                              ---> LDAP Respository
Client -> LDAP -> SDO/DAS ->
                                              ---> RDB Repository


Or it's going to be two ways to access the repository, the current way using
LDAP, and also a new way using SDO/DAS ?

-- 
Luciano Resende
http://people.apache.org/~lresende

On 3/21/07, Ole Ersoy <ole.ersoy@gmail.com> wrote:
>
> OK - Cool - So for LDAP DAS version 1.0
> I'll just write the entire SDO datagraph to ADS with each
> SDO object being an entry.
>
> Also, (Just wanted to make sure I understand)  are you saying that
> having a RDB backend because of:
>
> High volumes
> Reliability
> Replications
> Marketing
>
> Makes sense?
>
>
> Emmanuel Lecharny wrote:
> >
> >
> > On 3/21/07, *Ole Ersoy* <ole.ersoy@gmail.com
> > <mailto:ole.ersoy@gmail.com>> wrote:
> >
> >     Emmanuel,
> >
> >     I think my squirrel brain is starting to put together what you are
> >     saying :-)
> >
> >     Let me see if I'm getting it.
> >
> >     ATTRIBUTES VS. ENTIRE OBJECT
> >     Whether we pass an entire object or an individual attribute to ADS
> >     when
> >     updating,
> >     performance wise there's probably no difference since it's such a
> >     small
> >     chunk of info.
> >
> >
> > In fact, we pass attributes and we update them in a whole object
> > before storing it. To be able to do that, we first have to get the
> > whole object out of the backend. For instance, if you want to add a
> > userPassord to the uid=oersoy, dc=apache, dc=com entry, you will just
> > pass a modifyRequest with the DN, and the userPassord attribute with
> > the value to add. Then the server will search for the corresponding
> > entry from its DN, and if found, it will read it entirely. Then it
> > will add the attribute into the entry, and save it into the backend.
> >
> >     This applies at when ADS serialized to disk and when the Application
> >     sends data to ADS
> >     via the directory context per the criteria that object's size is
> >     below a
> >     certain number of KB.
> >
> >
> > Well, the criteria must still be implemented ... It's now 2 years we
> > know we have to deal with such a criteria, but we didn't had time to
> > implement it yes... 1.5.2 maybe
> >
> >     So from a "Passing the Baton" point of view, it does not matter
> >     whether
> >     it is a attribute or
> >     an object...since their size different is typically so small.
> >
> >
> > We can say that
> >
> >     Since this is the case, then the DAS implementation will be really
> >     straight forward I think.
> >
> >
> > Well, it's pretty much done in two classes only,
> > AttributesSerializerUtils and AttributeSerializerUtils. Only 700 lines
> > of code, javadoc included :)
> >
> >     I'll just skip commenting on the rest of your in lined comments, if
> I
> >     understand correctly,
> >     since the rest is not really important anyways.
> >
> >     JUST A SIDE NOTE:
> >
> >     RDB Backend for ApacheDS
> >     If we did this, then passing an attribute instead of an Object might
> >     make sense, if I understand correctly.
> >
> >
> > yep.
> >
> >     From what I understand rear ends like Prevayler
> >     are thousands of times faster than any RDB, even if the entire RDB
> >     were
> >     stored in main memory (Like with hsql),
> >     so would there ever be a point in using an RDB?
> >
> >
> > There are many, including high volumes, reliability, replications,
> > marketing, "We already have Or*cle/I*m db*/MySql/PostGresql" (TM), ...
> >
> >     I mention this because Tuscany also has a DAS for RDB.
> >
> >
> > We have had discussion with Tuscany guys in Austin about including ADS
> > into tuscany.
> >
> >     So an SDO model could serve as a middle tier between RDB
> >     persistance and
> >     LDAP persistance.
> >
> >
> > That may be a very good idea, because then it may abstract totally the
> > plumbery between ADS and the backend. At the moment, this plubery is
> > not really satisfactory.
> >
> >     Applications that need an RDB rear end, could pull info out of ADS
> >     using
> >     the
> >     DAS for LDAP, and store in in any RDB using DAS for RDB...
> >
> >
> > Yep.
> >
> >     Anyways, should probably put that in a different thread or JIRA or
> >     something...or the ADS
> >     design document that I need to get started...
> >
> >
> > We are seriously thinking about it for a 2.0 version of ADS. We might
> > discuss this  in may, during ApacheCon (if the number of beers we will
> > absorb, not to mention the strange substances we will smoke, keep our
> > brain productive :)
> >
> >
> > --
> > Cordialement,
> > Emmanuel L├ęcharny
> > www.iktek.com <http://www.iktek.com>
>
>

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