On 2/13/16 4:56 PM, Markus Kroetzsch wrote: > And here is another comment on this interesting topic :-) > > I just realised how close the service is to answering the query. It > turns out that you can in fact get the whole set of (currently >324000 > result items) together with their GND identifiers as a download > *within the timeout* (I tried several times without any errors). This > is a 63M json result file with >640K individual values, and it > downloads in no time on my home network. The query I use is simply this: > > PREFIX wd: <http://www.wikidata.org/entity/> > PREFIX wdt: <http://www.wikidata.org/prop/direct/> > > select ?item ?gndId > where { > ?item wdt:P227 ?gndId ; # get gnd ID > wdt:P31 wd:Q5 . # instance of human > } ORDER BY ASC(?gndId) LIMIT 10 > > (don't run this in vain: even with the limit, the ORDER clause > requires the service to compute all results every time someone runs > this. Also be careful when removing the limit; your browser may hang > on an HTML page that large; better use the SPARQL endpoint directly to > download the complete result file.) > > It seems that the timeout is only hit when adding more information > (labels and wiki URLs) to the result. > > So it seems that we are not actually very far away from being able to > answer the original query even within the timeout. Certainly not as > far away as I first thought. It might not be necessary at all to > switch to a different approach (though it would be interesting to know > how long LDF takes to answer the above -- our current service takes > less than 10sec). > > Cheers, > > Markus
For a page-size of 20 (covered by LIMIT) you can move through offets of 20 via: First call: PREFIX wd: <http://www.wikidata.org/entity/> PREFIX wdt: <http://www.wikidata.org/prop/direct/> select ?item ?gndId where { ?item wdt:P227 ?gndId ; # get gnd ID wdt:P31 wd:Q5 . # instance of human } ORDER BY ASC(?gndId) OFFSET 10 LIMIT 10 Next call: PREFIX wd: <http://www.wikidata.org/entity/> PREFIX wdt: <http://www.wikidata.org/prop/direct/> select ?item ?gndId where { ?item wdt:P227 ?gndId ; # get gnd ID wdt:P31 wd:Q5 . # instance of human } ORDER BY ASC(?gndId) OFFSET 20 LIMIT 10 Subsequent Calls: PREFIX wd: <http://www.wikidata.org/entity/> PREFIX wdt: <http://www.wikidata.org/prop/direct/> select ?item ?gndId where { ?item wdt:P227 ?gndId ; # get gnd ID wdt:P31 wd:Q5 . # instance of human } ORDER BY ASC(?gndId) OFFSET {last-offset-plus-20} LIMIT 10 Remember, you simply change the OFFSET value in the SPARQL HTTP URL. -- Regards, Kingsley Idehen Founder & CEO OpenLink Software Company Web: http://www.openlinksw.com Personal Weblog 1: http://kidehen.blogspot.com Personal Weblog 2: http://www.openlinksw.com/blog/~kidehen Twitter Profile: https://twitter.com/kidehen Google+ Profile: https://plus.google.com/+KingsleyIdehen/about LinkedIn Profile: http://www.linkedin.com/in/kidehen Personal WebID: http://kingsley.idehen.net/dataspace/person/kidehen#this
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