- From: Paul Gearon <gearon@ieee.org>
- Date: Fri, 28 Aug 2009 07:28:59 -0400
- To: Andreas Langegger <al@jku.at>
- Cc: "Seaborne, Andy" <andy.seaborne@hp.com>, Niklas Lindström <lindstream@gmail.com>, Semantic Web <semantic-web@w3.org>
2009/8/27 Andreas Langegger <al@jku.at>: > On Aug 27, 2009, at 12:11 AM, Seaborne, Andy wrote: >> >> it's a tradeoff of generality and data validity assumptions. > > and generality of RDF compared to multiple tables with their own indexable > attributes in RDBMS. > > I'm wondering for some time already if there is any triple store that allows > to define custom indexes on special predicates or subsets of the whole set > of triples/quads? All the existing stores I know index over all triples in > different combinations (spo, pso, ...). Is there any research going on > towards partial indexes over user-defined subsets of triples? E.g. an index > over all xsd:dateTime literals. Mulgara indexes through all of the XSD datatypes, including xsd:dateTime literals. It's mostly used for optimizing when finding intervals. Unfortunately, there is no optimization to take advantage of this when doing an ORDER BY on a literal field (though now that it's been mentioned, I'll have to get to it). Regards, Paul Gearon
Received on Friday, 28 August 2009 11:29:38 UTC