- From: Kendall Grant Clark <kendall@clarkparsia.com>
- Date: Wed, 14 May 2008 14:25:57 -0400
- To: Michael F Uschold <uschold@gmail.com>
- Cc: 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>, Kingsley Idehen <kidehen@openlinksw.com>, 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>
Excerpts from Michael F Uschold's message of Wed May 14 12:06:36 -0400 2008: > > **JimHendler *summarized things this way: "So what you are really saying is > scaling is a technology/research challenge now that there's much more out > there. We need to go beyond just triple stores and get some fast inferencing > at Web scales. Makes sense to me." Absolutely. But it's gotten harder lately to find support for that research, IMO. We've been working on this for OWL2 DL-Lite and for EL++, two tractable profiles of OWL (as Jim well knows! :>). The next version of Pellet [1] will include an EL-optimized reasoner (though not over secondary storage), and we just released Owlgres 0.1 [2], which is an OWL2 DL-Lite reasoner for Postgresql for large data sets. > *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. Cheers, Kendall Clark 1 http://pellet.owldl.com/ 2 http://pellet.owldl.com/owlgres
Received on Wednesday, 14 May 2008 18:26:45 UTC