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Re: Tests: data-r2/algebra

From: Jeen Broekstra <j.broekstra@tue.nl>
Date: Thu, 14 Jun 2007 11:12:57 +0200
Message-ID: <46710699.3090703@tue.nl>
To: Jeen Broekstra <j.broekstra@tue.nl>
CC: andy.seaborne@hp.com, RDF Data Access Working Group <public-rdf-dawg@w3.org>

Jeen Broekstra wrote:
> I'm having difficulties with the first test, Nested Optionals 1.


Following up on myself here, I think that this has to do with the fact
that the test query's graph pattern is not "well designed" (see Perez et
al., section 4.2).

This leads to a difference in evaluation results between Sesame's query
evaluation approach (which is depth-first) and the compositional
approach (which is presumably what the algebra advocates).

It might be useful to document this somehow as there are bound to be
other depth-first implementations out there that will fail these kinds
of patterns.

Dr. Jeen Broekstra                                          Den Dolech 2
Information Systems Group                                        HG 7.76
Department of Mathematics and Computer Science              P.O. Box 513
Technische Universiteit Eindhoven                      5600 MB Eindhoven
tel. +31 (0)40 247 36 86                                 The Netherlands
Received on Thursday, 14 June 2007 09:16:41 UTC

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