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Re: Managing Co-reference (Was: A Semantic Elephant?)

From: Kingsley Idehen <kidehen@openlinksw.com>
Date: Wed, 14 May 2008 16:08:39 -0400
Message-ID: <482B46C7.6080406@openlinksw.com>
To: Kendall Grant Clark <kendall@clarkparsia.com>
CC: Michael F Uschold <uschold@gmail.com>, Tim Berners-Lee <timbl@w3.org>, Sören Auer <auer@informatik.uni-leipzig.de>, Chris Bizer <chris@bizer.de>, Frank van Harmelen <frank.van.harmelen@cs.vu.nl>, Semantic Web Interest Group <semantic-web@w3.org>, "Fabian M. Suchanek" <f.m.suchanek@gmail.com>, Tim Berners-Lee <timbl@csail.mit.edu>, jim hendler <hendler@cs.rpi.edu>, Mark Greaves <markg@vulcan.com>, "georgi.kobilarov" <georgi.kobilarov@gmx.de>, Jens Lehmann <lehmann@informatik.uni-leipzig.de>, Richard Cyganiak <richard@cyganiak.de>, Frederick Giasson <fred@fgiasson.com>, Michael Bergman <mike@mkbergman.com>, Conor Shankey <cshankey@reinvent.com>, Kira Oujonkova <koujonkova@reinvent.com>, Aldo Gangemi <aldo.gangemi@istc.cnr.it>, Ivan Mikhailov <iv@openlinksw.com>, Orri Erling <oerling@openlinksw.com>, Alan Ruttenberg <alanruttenberg@gmail.com>

Kendall Grant Clark wrote:
> Excerpts from Kingsley Idehen's message of Wed May 14 14:59:29 -0400 2008:
>> Owlgres is a PostgreSQL application. Why the DBMS specificity?
> Because it makes for a better name, obviously... ;>
> Seriously, it's not Postgres specific. We prefer Postgresql, but Owlgres ca
> run on any JDBC-compliant database. I suspect that, as it matures and we find a
> customer base for it, it will run on a variety of databases.
Okay, the JDBC bit is good, and we can easily test Owlgres against 
Virtuoso JDBC.  But of course, we end up with the obvious question: Why 
are we using JDBC to talk to a DBMS engine equipped with a Quad Store? 
We've been through this re. recent work relating to new Model Providers 
for Sesame, Jena, and Redland (all of which offer SQL DBMS and Graph 
Model persistence  APIs).
>> What does PosgreSQL offer that you may have assumed is/was missing from 
>> Virtuoso when developing this application?
> I don't know why you're assuming that I assumed anything, but the primary
> reasons we chose Postgresql were maturity, scalability, extensibility, vibrant
> after-market, BSD license, and PostGIS.

Bad choice of words on my part re: is/was :-)

Since I haven't had time to look under the hood, I want you to assist me 
in understanding what PostgreSQL offered that lead to what I assumed was 
a PostgreSQL specific application.
>> I've also added, Orri Erling (Program Manager Virtuoso), Ivan Mikhailov 
>> (Lead Developer of Virtuoso's Quad Store functionality realm), and Alan 
>> Rutternberg to this thread (Alan is interested in Owlgres and Virtuoso 
>> integration).
> If you'd like to have a conversation with Alan or others about Owlgres working
> w/ Virtuoso, we can do that offline or at SemTech next week, but I don't think
> it's very relevant here.
Sure, we can take that offline, but note the context of my comments 
(above plus the bit below):

> > *MikeUschold *noted that the computational issue of owl:sameAs proliferation
> > is a major problem, even if noone is going to load all the semantic web data
> > into a single store.  For today's triple stores that do limited inference,
> > owl:sameAs "has a significant run time" according both to common sense as
> > well as the developers of OpenLink's Virtuoso triple
> > store<http://docs.openlinksw.com/virtuoso/rdfsparqlrule.html#rdfsparqlruleintro>
> > .
> > They say it can easily double query
> > times<http://www.openlinksw.com/weblog/oerling/?id=1347>.

You don't have to  do it at query time. Owlgres  does owl:sameAs processing at
load time and so the *query time*  cost is negligible. The usual caveats about
tradeoffs and use cases apply, of course.


 I am trying to determine if  we've ended up with  two things that are 
artificially disconnected :-)
> Cheers,
> Kendall



Kingsley Idehen	      Weblog: http://www.openlinksw.com/blog/~kidehen
President & CEO 
OpenLink Software     Web: http://www.openlinksw.com
Received on Wednesday, 14 May 2008 20:09:21 UTC

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