Kingsley, On 29 Jan 2013, at 13:58, Kingsley Idehen <kide...@openlinksw.com> wrote:
> On 1/29/13 8:26 AM, Dimitris Kontokostas wrote:
>> 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
>
> Okay.
>
> Patrick/Hugh: do you have some of the guides relating to this matter?
[Hugh] This is one on the posts I have made on the matter in the past, could be
massaged into a public document on the dbpedia web site:
http://lists.w3.org/Archives/Public/public-lod/2011Aug/0028.html
Regards
Hugh
>
> Links:
>
> 1.
> http://stackoverflow.com/questions/8328720/sparql-query-to-get-all-the-possible-movies-available-from-dbpedia
>
> 2.
> http://www.openlinksw.com/dataspace/dav/wiki/Main/VirtTipsAndTricksHowToHandleBandwidthLimitExceed
> ,
>
> Kingsley
>>
>>
>>
>>
>> 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>
>>> 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
>>>
>>>
>>>
>>>
>>>
>>>
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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
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>>> 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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>>
>>
>> --
>>
>> 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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>> MVC, Windows 8 Apps, JavaScript and much more. Keep your skills current
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>> MVPs and experts. ON SALE this month only -- learn more at:
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>>
>>
>>
>>
>> --
>> Kontokostas Dimitris
>
>
> --
>
> 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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