On 8/3/17 2:32 PM, Paul Houle wrote:
> he following query runs well on the public SPARQL endpoint:
>
> SELECT ?type (COUNT(*) AS ?count) {
> ?station a dbo:CareerStation .
> ?who dbo:careerStation ?station .
> ?who a ?type .
> } GROUP BY ?type ORDER BY DESC(?count)
>
> It completes in a few seconds, the only trouble with it is that there
> are 400,000 or so YAGO types in the system, so the query hits the
> 10,000 row limit.
>
> If I want only dbo types, I write the following query:
>
> SELECT ?type (COUNT(*) AS ?count) {
> ?station a dbo:CareerStation .
> ?who dbo:careerStation ?station .
> ?who a ?type .
> FILTER(STRSTARTS(STR(?type),"http://dbpedia.org/ontology/";))
> } GROUP BY ?type ORDER BY DESC(?count)
>
> which does not finish at all if I submit it with the rdflib sparql
> protocol client) (giving the default graph http://dbpedia.org),
> failing with error message "Virtuoso S1T00 Error SR171: Transaction
> timed out"
>
> Now that query *does* work through the web interface when it has the
> default "30000" timeout. However, I find then that the number of
> results depends on the timeout, for instance with a timeout of 5000 I get
>
> type count
> http://dbpedia.org/ontology/Person
> 15741
> http://dbpedia.org/ontology/Agent
> 15741
> http://dbpedia.org/ontology/Athlete
> 12378
> http://dbpedia.org/ontology/SoccerPlayer
> 12378
> http://dbpedia.org/ontology/SoccerManager
> 3363
> http://dbpedia.org/ontology/SportsManager
> 3363
>
>
> and with 10000 I get
>
> type count
> http://dbpedia.org/ontology/Person
> 28962
> http://dbpedia.org/ontology/Agent
> 28962
> http://dbpedia.org/ontology/Athlete
> 23546
> http://dbpedia.org/ontology/SoccerPlayer
> 23546
> http://dbpedia.org/ontology/SoccerManager
> 5416
> http://dbpedia.org/ontology/SportsManager
> 5416
>
>
> This wasn't what I expected, what's up?
>The larger the timeout the larger solution. This is what we call "Any Time Query" solution i.e., providing partial results (which is indicated via HTTP response header metadata) for queries that don't complete within allotted timeout. Remember, anybody could be running any combination of these kinds of queries at any time. The DBMS challenge is all about offering fair use of the DBpedia endpoint, to the planet. -- Regards, Kingsley Idehen Founder & CEO OpenLink Software (Home Page: http://www.openlinksw.com) Weblogs (Blogs): Legacy Blog: http://www.openlinksw.com/blog/~kidehen/ Blogspot Blog: http://kidehen.blogspot.com Medium Blog: https://medium.com/@kidehen Profile Pages: Pinterest: https://www.pinterest.com/kidehen/ Quora: https://www.quora.com/profile/Kingsley-Uyi-Idehen Twitter: https://twitter.com/kidehen Google+: https://plus.google.com/+KingsleyIdehen/about LinkedIn: http://www.linkedin.com/in/kidehen Web Identities (WebID): Personal: http://kingsley.idehen.net/public_home/kidehen/profile.ttl#i : http://id.myopenlink.net/DAV/home/KingsleyUyiIdehen/Public/kingsley.ttl#this
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