Hi Kingsley,
I know that you wrote about this many times in the past but people usually
do not bother to search the archives, plus that the sourceforge search
capabilities are not very user friendly :)
We should start documenting common queries in the DBpedia wiki
and this is indeed a very common one.
(Although I must admit that I didn't know about the latest selectivity
behaviour you described)
If this is documented somewhere in the Openlink website we could also put
just a link and the next time someone asks we can just provide the a link
to the answer.
It will save us time in the long run ;)
Best,
Dimitris
On Tue, Jan 29, 2013 at 2:29 PM, Kingsley Idehen <kide...@openlinksw.com>wrote:
> 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
>
> ------------------------------
>
> *De: *"Kingsley Idehen" <kide...@openlinksw.com> <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/Ludwig_M%C3%BCller_%28theologian%29>
>> 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.cominstance 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
>>>
>>>
>>>
>>>
>>>
>>>
>>>
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>>>
>>
>>
>> --
>>
>> 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
>
>
>
>
>
> ------------------------------------------------------------------------------
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> with LearnDevNow - 3,200 step-by-step video tutorials by Microsoft
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> 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
>
>
>
>
>
> ------------------------------------------------------------------------------
> 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:
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--
Kontokostas Dimitris
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