- From: Polleres, Axel <axel.polleres@siemens.com>
- Date: Wed, 14 Mar 2012 11:45:22 +0100
- To: Andy Seaborne <andy.seaborne@epimorphics.com>, "public-rdf-dawg@w3.org" <public-rdf-dawg@w3.org>
(sorry, hot "send" to early) > Could you expand on "we need DISTINCT"? Is that just a technical > point that DISTINCT covers more or a political point about the > comments? For me this is definitly a technical point, since a DISTINCT-paths -semantics, which can be optimized/efficiently implemented, doesn't seem to be feasible by recognizing DISTINCT subqueries alone, at least not trivially... I.e., while DISTINCT() can possibly be defined in terms of a rewriting (which introduces fresh variables for blank nodes), I think that's neither elegant nor very practical for optimizations without the explicit keyword, whereas a syntactic element DISTINCT() gives a direct handle for optimizations, right? So, I think this is important *both* technically and in in order to address the comments. > What about the lesser case of just {*}{+} and *+ changes? I am fine with having those, but for the reasons above, I would feel uncomfortable going without DISTINCT(). Best, Axel -- Dr. Axel Polleres Siemens AG Österreich Corporate Technology Central Eastern Europe Research & Technologies CT T CEE Tel.: +43 (0) 51707-36983 Mobile: +43 (0) 664 88550859 Fax: +43 (0) 51707-56682 mailto:axel.polleres@siemens.com > > -----Original Message----- > > From: Andy Seaborne [mailto:andy.seaborne@epimorphics.com] > > Sent: 14 March 2012 11:02 > > To: public-rdf-dawg@w3.org > > Subject: Re: DISTINCT() > > > > On 14/03/12 09:48, Polleres, Axel wrote: > > > Just my two cents to emphasize that I tend to agree on > > that: I believe > > > we need DISTINCT() to address JC-4 and related comments in > > a fashion > > > agreeable to the commenters. > > > > Could you expand on "we need DISTINCT"? Is that just a > > technical point that DISTINCT covers more or a political > > point about the comments? > > > > What about the lesser case of just {*}{+} and *+ changes? > > > > Andy > > > >
Received on Wednesday, 14 March 2012 10:45:50 UTC