Getting list of persons using SPARQL dbpedia

问题

I am using live-dbpedia to retrieve the list of persons. I am executing a sparql query on live-dbpedia endpoints to get the result.I have fixed the offset and limit value in the query and getting the records after each 10000 attempt. But when I was trying to execute at 580000 offset value, 504 Gateway Time-out error happens.

Not Working SPARQL Query:

SELECT DISTINCT ?dbpedia_link str(?name) as ?label str(?label1) as ?label1 ?freebase_link WHERE {
        ?dbpedia_link rdfs:label ?label1 . 
        ?dbpedia_link foaf:name ?name .
        {
         { ?dbpedia_link rdf:type dbpedia-owl:Person }                            
        }                        
        OPTIONAL {?dbpedia_link owl:sameAs ?freebase_link .
        FILTER regex(?freebase_link, "^http://rdf.freebase.com") .}
        FILTER (lang(?label1) = 'en'). 
        ?dbpedia_link dcterms:subject ?sub 
        }Limit 1000
        OFFSET 580000

Working SPARQL Query :

SELECT DISTINCT ?dbpedia_link str(?name) as ?label str(?label1) as ?label1 ?freebase_link WHERE {
            ?dbpedia_link rdfs:label ?label1 . 
            ?dbpedia_link foaf:name ?name .
            {
             { ?dbpedia_link rdf:type dbpedia-owl:Person }                            
            }                        
            OPTIONAL {?dbpedia_link owl:sameAs ?freebase_link .
            FILTER regex(?freebase_link, "^http://rdf.freebase.com") .}
            FILTER (lang(?label1) = 'en'). 
            ?dbpedia_link dcterms:subject ?sub 
            }Limit 1000
            OFFSET 50000

How to overcome this problem.

回答1:

Put a delay between your requests. There is a rate limit in the live endpoint and this is the error you get when you exceed it. There is also a short timeout to make the service more available.

(Disclaimer: I am responsible for the service)

来源：https://stackoverflow.com/questions/26134637/getting-list-of-persons-using-sparql-dbpedia

标签

sparql

dbpedia