Hi,
Sorry if I sounded complaining about the quality of service of dbpedia.
I understand there is a big load on the server and that some limits must be
enforced to that it would not be overloaded with big queries.
My concern is how to know when a query reaches one limit so that I can split
the query to get the results by chunks.
As far as I saw in the mailing list messages, the causes of partial results
could be about default (implicit) limits on the number of results.
So I though until now that if I put explicit limit in my query I would either
get the full result or an exception.
But this doesn't seem to be the case in the example given by Andrea :
> select distinct ?s where {
> ?s dbpedia-owl:birthPlace
> <http://dbpedia.org/resource/G%C3%BCtersloh>
> } limit 100
there should be 11 results, sometimes only 5 are given, and the response is
given straight away.
I am also running an image of DBpedia on virtuoso and I want to understand this
to know at least when it can happen.
You said there is a way to know when a result is incomplete with the SPARQL
Protocol, I have to look at this.
Thanks,
Julien
----- Mail original -----
> De: "Kingsley Idehen" <kide...@openlinksw.com>
> À: "Julien Cojan" <julien.co...@inria.fr>
> Cc: dbpedia-discussion@lists.sourceforge.net
> Envoyé: Mardi 29 Janvier 2013 13:29:52
> Objet: Re: [Dbpedia-discussion] Sparql query vs. web interface
> On 1/29/13 5:12 AM, Julien Cojan wrote:
> > Hi,
>
> > This seems to be the same question as in [1], though there was no
> > answer to that.
>
> > The fact that virtuoso doesn't always provide all the results to a
> > query is disturbing.
>
> Again, it would be disturbing if it allowed anyone to use the
> instance without consideration for others. Do you have any idea how
> many concurrent connections hit this instance at any given time of
> the day, from anywhere on the Web?
> > Is there a way to know when this happens ?
>
> Yes, via SPARQL Protocol (an HTTP service) you are able to determine
> if results are complete or note. Please understand, we set up this
> instance with a specific goal in mind i.e., we are not going to
> allow crawlers hog the instance at the expense of others.
> > If it's a processing time issue, why doesn't it just fail with a
> > timeout exception or a warning as it does sometimes ?
>
> Because you have two parameters in play, a timeout (which you can
> set) and total query cost. What you should do is increase the
> timeout and then use offset and limit. Tailor it to your needs. You
> use cursor over the data instead of blindly asking for everything
> that matches your query.
> Also note, this is why we provide an Amazon EC2 AMI for you to
> construct your own instance and use it exclusively in the manner
> that works best for you. Same thing applies if you want to install
> on your own setup.
> Again, DBpedia endpoint is for World Wide access. Its configured to
> meet that need.
> Please search search on this forum (go back a few years) for examples
> and comments about these matters.
> Endpoints:
> 1. http://dbpedia.org/sparql -- basic setup
> 2. http://lod.openlinksw.com/sparql -- larger setup which can handle
> more concurrent users and expensive query combos.
> Kingsley
> > Regards,
>
> > Julien
>
> > [1] http://sourceforge.net/mailarchive/message.php?msg_id=30351258
>
> > ----- Mail original -----
>
> > > De: "Kingsley Idehen" <kide...@openlinksw.com>
> >
>
> > > À: dbpedia-discussion@lists.sourceforge.net
> >
>
> > > Envoyé: Lundi 28 Janvier 2013 22:36:59
> >
>
> > > Objet: Re: [Dbpedia-discussion] Sparql query vs. web interface
> >
>
> > > On 1/28/13 4:26 PM, Andrea Di Menna wrote:
> >
>
> > > > Thanks Kingsley.
> > >
> >
>
> > > > Is the same reason why all the resources are not listed in the
> > > > http://dbpedia.org/page/G%C3%BCtersloh page as reverse
> > > > dbpedia-owl:birthPlace property?
> > >
> >
>
> > > Yes, since this URL will give varying results, subject what other
> > > connections to doing with the DBMS:
> >
>
> > > http://dbpedia.org/sparql?default-graph-uri=http%3A%2F%2Fdbpedia.org&query=prefix+dbpedia-owl%3A+%3Chttp%3A%2F%2Fdbpedia.org%2Fontology%2F%3E%0D%0Aselect+%3Fs+where+%7B%3Fs+dbpedia-owl%3AbirthPlace+%3Chttp%3A%2F%2Fdbpedia.org%2Fresource%2FG%25C3%25BCtersloh%3E%7D&format=text%2Fhtml&timeout=0&debug=on
> >
>
> > > Query Definition:
> >
>
> > > http://dbpedia.org/sparql?default-graph-uri=http%3A%2F%2Fdbpedia.org&qtxt=prefix+dbpedia-owl%3A+%3Chttp%3A%2F%2Fdbpedia.org%2Fontology%2F%3E%0D%0Aselect+%3Fs+where+%7B%3Fs+dbpedia-owl%3AbirthPlace+%3Chttp%3A%2F%2Fdbpedia.org%2Fresource%2FG%25C3%25BCtersloh%3E%7D&format=text%2Fhtml&timeout=0&debug=on
> >
>
> > > LOD Cloud:
> >
>
> > > http://lod.openlinksw.com/sparql?default-graph-uri=http%3A%2F%2Fdbpedia.org&query=prefix+dbpedia-owl%3A+%3Chttp%3A%2F%2Fdbpedia.org%2Fontology%2F%3E%0D%0Aselect+%3Fs+where+%7B%3Fs+dbpedia-owl%3AbirthPlace+%3Chttp%3A%2F%2Fdbpedia.org%2Fresource%2FG%25C3%25BCtersloh%3E%7D&format=text%2Fhtml&timeout=0&debug=on
> >
>
> > > Kingsley
> >
>
> > > > Thanks
> > >
> >
>
> > > > 2013/1/28 Kingsley Idehen < kide...@openlinksw.com >
> > >
> >
>
> > > > > On 1/28/13 3:53 PM, Andrea Di Menna wrote:
> > > >
> > >
> >
>
> > > > > > Hi Kingsley,
> > > > >
> > > >
> > >
> >
>
> > > > > > just wanted to add that sometimes.
> > > > >
> > > >
> > >
> >
>
> > > > > > The same query:
> > > > >
> > > >
> > >
> >
>
> > > > > > http://dbpedia.org/sparql?default-graph-uri=http%3A%2F%2Fdbpedia.org&query=select+%3Fperson+where+%7B%3Fperson+%3Chttp%3A%2F%2Fdbpedia.org%2Fontology%2FbirthPlace%3E+%3Chttp%3A%2F%2Fdbpedia.org%2Fresource%2FG%25C3%25BCtersloh%3E+%7D&format=text%2Fhtml&timeout=2000
> > > > >
> > > >
> > >
> >
>
> > > > > > from time to time returns only 5 results (which are the
> > > > > > ones
> > > > > > shown
> > > > > > here http://dbpedia.org/page/G%C3%BCtersloh )
> > > > >
> > > >
> > >
> >
>
> > > > > > When the query returns 11 elements they are:
> > > > >
> > > >
> > >
> >
>
> > > > > > http://dbpedia.org/resource/Hans_Werner_Henze
> > > > >
> > > >
> > >
> >
>
> > > > > > http://dbpedia.org/resource/Diana_Amft
> > > > >
> > > >
> > >
> >
>
> > > > > > http://dbpedia.org/resource/Ludwig_M%C3%BCller_(theologian)
> > > > >
> > > >
> > >
> >
>
> > > > > > http://dbpedia.org/resource/Hanns-Heinrich_Lohmann
> > > > >
> > > >
> > >
> >
>
> > > > > > http://dbpedia.org/resource/Andy_Duguid
> > > > >
> > > >
> > >
> >
>
> > > > > > http://dbpedia.org/resource/Wolf_Hilbertz
> > > > >
> > > >
> > >
> >
>
> > > > > > http://dbpedia.org/resource/Simon_Gosejohann
> > > > >
> > > >
> > >
> >
>
> > > > > > http://dbpedia.org/resource/Friedrich_Daniel_von_Recklinghausen
> > > > >
> > > >
> > >
> >
>
> > > > > > http://dbpedia.org/resource/Theodor_Rumpel_(surgeon)
> > > > >
> > > >
> > >
> >
>
> > > > > > http://dbpedia.org/resource/Thorsten_Stuckmann
> > > > >
> > > >
> > >
> >
>
> > > > > > http://dbpedia.org/resource/Annabel_J%C3%A4ger
> > > > >
> > > >
> > >
> >
>
> > > > > > By checking the first one, you can see that it has
> > > > > > http://dbpedia.org/page/G%C3%BCtersloh as
> > > > > > dbpedia-owl:birthPlace.
> > > > >
> > > >
> > >
> >
>
> > > > > > But this is not shown in the
> > > > > > http://dbpedia.org/page/G%C3%BCtersloh
> > > > > > page as a reverse property.
> > > > >
> > > >
> > >
> >
>
> > > > > > Do you know what is wrong?
> > > > >
> > > >
> > >
> >
>
> > > > > Basic SPARQL endpoint is protected by query cost controls
> > > > > based
> > > > > on
> > > > > the backed end machine config etc.. That's why I used the
> > > > > lod.openlinksw.com instance as an example since that's a
> > > > > bigger
> > > > > machine setup with the same data.
> > > >
> > >
> >
>
> > > > > See:
> > > > > http://dbpedia.org/describe/?url=http%3A%2F%2Fdbpedia.org%2Fresource%2FG%25C3%25BCtersloh
> > > > > -- this has more results because it makes use of DBMS hosted
> > > > > cursors
> > > > > for scrolling through the dataset .
> > > >
> > >
> >
>
> > > > > You can use OFFSET and LIMIT to page through the data. I am
> > > > > sure
> > > > > there are some old posts about these matters re. DBpedia's
> > > > > SPARQL
> > > > > endpoint.
> > > >
> > >
> >
>
> > > > > Kingsley
> > > >
> > >
> >
>
> > > > > > Regards
> > > > >
> > > >
> > >
> >
>
> > > > > > 2013/1/28 Kingsley Idehen < kide...@openlinksw.com >
> > > > >
> > > >
> > >
> >
>
> > > > > > > On 1/28/13 3:15 PM, Daniel Naber wrote:
> > > > > >
> > > > >
> > > >
> > >
> >
>
> > > > > > > > Hi,
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
>
> > > > > > > > I'd like to find all persons born in a given city. At
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
>
> > > > > > > > http://de.dbpedia.org/page/G%C3%BCtersloh I see about
> > > > > > > > 96
> > > > > > > > persons.
> > > > > > > > When I
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
>
> > > > > > > > query with Sparql, I only get 11. The query I use is
> > > > > > > > this:
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
>
> > > > > > > > select ?person where {?person <
> > > > > > > > http://dbpedia.org/ontology/birthPlace >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
>
> > > > > > > > < http://dbpedia.org/resource/G%C3%BCtersloh >}
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
>
> > > > > > > > The endpoint I use is http://dbpedia.org/sparql . How
> > > > > > > > can
> > > > > > > > I
> > > > > > > > get
> > > > > > > > all
> > > > > > > > the
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
>
> > > > > > > > results that are shown on the web page?
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
>
> > > > > > > > Regards
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
>
> > > > > > > > Daniel
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
>
> > > > > > > Try:
> > > > > >
> > > > >
> > > >
> > >
> >
>
> > > > > > > http://lod.openlinksw.com/sparql?default-graph-uri=&query=select+distinct+%3Fperson+where+%7B%3Fperson+%3Chttp%3A%2F%2Fdbpedia.org%2Fontology%2FbirthPlace%3E+%0D%0A%3Chttp%3A%2F%2Fdbpedia.org%2Fresource%2FG%25C3%25BCtersloh%3E%7D&format=text%2Fhtml&timeout=30000&debug=on
> > > > > >
> > > > >
> > > >
> > >
> >
>
> > > > > > > Query Definition:
> > > > > >
> > > > >
> > > >
> > >
> >
>
> > > > > > > http://lod.openlinksw.com/sparql?default-graph-uri=&qtxt=select+distinct+%3Fperson+where+%7B%3Fperson+%3Chttp%3A%2F%2Fdbpedia.org%2Fontology%2FbirthPlace%3E+%0D%0A%3Chttp%3A%2F%2Fdbpedia.org%2Fresource%2FG%25C3%25BCtersloh%3E%7D&format=text%2Fhtml&timeout=30000&debug=on
> > > > > >
> > > > >
> > > >
> > >
> >
>
> > > > > > > --
> > > > > >
> > > > >
> > > >
> > >
> >
>
> > > > > > > Regards,
> > > > > >
> > > > >
> > > >
> > >
> >
>
> > > > > > > Kingsley Idehen
> > > > > >
> > > > >
> > > >
> > >
> >
>
> > > > > > > Founder & CEO
> > > > > >
> > > > >
> > > >
> > >
> >
>
> > > > > > > OpenLink Software
> > > > > >
> > > > >
> > > >
> > >
> >
>
> > > > > > > Company Web: http://www.openlinksw.com
> > > > > >
> > > > >
> > > >
> > >
> >
>
> > > > > > > Personal Weblog: http://www.openlinksw.com/blog/~kidehen
> > > > > >
> > > > >
> > > >
> > >
> >
>
> > > > > > > Twitter/Identi.ca handle: @kidehen
> > > > > >
> > > > >
> > > >
> > >
> >
>
> > > > > > > Google+ Profile:
> > > > > > > https://plus.google.com/112399767740508618350/about
> > > > > >
> > > > >
> > > >
> > >
> >
>
> > > > > > > LinkedIn Profile: http://www.linkedin.com/in/kidehen
> > > > > >
> > > > >
> > > >
> > >
> >
>
> > > > > > > ------------------------------------------------------------------------------
> > > > > >
> > > > >
> > > >
> > >
> >
>
> > > > > > > Master Visual Studio, SharePoint, SQL, ASP.NET , C# 2012,
> > > > > > > HTML5,
> > > > > > > CSS,
> > > > > >
> > > > >
> > > >
> > >
> >
>
> > > > > > > MVC, Windows 8 Apps, JavaScript and much more. Keep your
> > > > > > > skills
> > > > > > > current
> > > > > >
> > > > >
> > > >
> > >
> >
>
> > > > > > > with LearnDevNow - 3,200 step-by-step video tutorials by
> > > > > > > Microsoft
> > > > > >
> > > > >
> > > >
> > >
> >
>
> > > > > > > MVPs and experts. ON SALE this month only -- learn more
> > > > > > > at:
> > > > > >
> > > > >
> > > >
> > >
> >
>
> > > > > > > http://p.sf.net/sfu/learnnow-d2d
> > > > > >
> > > > >
> > > >
> > >
> >
>
> > > > > > > _______________________________________________
> > > > > >
> > > > >
> > > >
> > >
> >
>
> > > > > > > Dbpedia-discussion mailing list
> > > > > >
> > > > >
> > > >
> > >
> >
>
> > > > > > > Dbpedia-discussion@lists.sourceforge.net
> > > > > >
> > > > >
> > > >
> > >
> >
>
> > > > > > > https://lists.sourceforge.net/lists/listinfo/dbpedia-discussion
> > > > > >
> > > > >
> > > >
> > >
> >
>
> > > > > --
> > > >
> > >
> >
>
> > > > > Regards,
> > > >
> > >
> >
>
> > > > > Kingsley Idehen
> > > >
> > >
> >
>
> > > > > Founder & CEO
> > > >
> > >
> >
>
> > > > > OpenLink Software
> > > >
> > >
> >
>
> > > > > Company Web: http://www.openlinksw.com Personal Weblog:
> > > > > http://www.openlinksw.com/blog/~kidehen Twitter/Identi.ca
> > > > > handle:
> > > > > @kidehen
> > > >
> > >
> >
>
> > > > > Google+ Profile:
> > > > > https://plus.google.com/112399767740508618350/about
> > > > > LinkedIn Profile: http://www.linkedin.com/in/kidehen
> > > >
> > >
> >
>
> > > --
> >
>
> > > Regards,
> >
>
> > > Kingsley Idehen
> >
>
> > > Founder & CEO
> >
>
> > > OpenLink Software
> >
>
> > > Company Web: http://www.openlinksw.com Personal Weblog:
> > > http://www.openlinksw.com/blog/~kidehen Twitter/Identi.ca handle:
> > > @kidehen
> >
>
> > > Google+ Profile:
> > > https://plus.google.com/112399767740508618350/about
> > > LinkedIn Profile: http://www.linkedin.com/in/kidehen
> >
>
> > > ------------------------------------------------------------------------------
> >
>
> > > Master Visual Studio, SharePoint, SQL, ASP.NET, C# 2012, HTML5,
> > > CSS,
> >
>
> > > MVC, Windows 8 Apps, JavaScript and much more. Keep your skills
> > > current
> >
>
> > > with LearnDevNow - 3,200 step-by-step video tutorials by
> > > Microsoft
> >
>
> > > MVPs and experts. ON SALE this month only -- learn more at:
> >
>
> > > http://p.sf.net/sfu/learnnow-d2d
> >
>
> > > _______________________________________________
> >
>
> > > Dbpedia-discussion mailing list
> >
>
> > > Dbpedia-discussion@lists.sourceforge.net
> >
>
> > > https://lists.sourceforge.net/lists/listinfo/dbpedia-discussion
> >
>
> --
> Regards,
> Kingsley Idehen
> Founder & CEO
> OpenLink Software
> Company Web: http://www.openlinksw.com Personal Weblog:
> http://www.openlinksw.com/blog/~kidehen Twitter/Identi.ca handle:
> @kidehen
> Google+ Profile: https://plus.google.com/112399767740508618350/about
> LinkedIn Profile: http://www.linkedin.com/in/kidehen------------------------------------------------------------------------------
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