Hello!
This looks like a bug, but we'll need more time to investigate and get to
the bottom of this. I've created
https://phabricator.wikimedia.org/T2704 to
track the issue. There isn't that many people around during this end of
year, so this will probably have to wait for January.
Thanks for your patience!
Guillaume
On Thu, Dec 17, 2020 at 4:06 PM Maciej Gawinecki <mgawinecki(a)gmail.com>
wrote:
Hi,
I am trying to get alternative names of given names in WikiData with the
following simple query:
PREFIX ps: <http://www.wikidata.org/prop/direct/>
PREFIX wd: <http://www.wikidata.org/entity/>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
CONSTRUCT {?s rdfs:label ?o}
WHERE { ?s ps:P31 wd:Q202444. ?s rdfs:label ?o}
LIMIT 1000
Initially, the query was much more complex, but I was getting time-outs on
the public WikiData SPARQL endpoint. I decided to use Linked Data Fragments
to offload some filtering from the server to the client.
comunica-sparql "https://query.wikidata.org/bigdata/ldf" -f query >
given_names.n3
(where "query" is a file with the SPARQL query shown above).
Unfortunately, the client tries to get output from the 3rd page, I am
getting the following error:
Could not retrieve
https://query.wikidata.org/bigdata/ldf?subject=http%3A%2F%2Fwww.wikidata.or…
(500: unknown error)
Following the link in fact returns HTTP 500 error with
Error details
java.lang.IllegalStateException
The link points to the 3rd page. It works if you try to go the second
page:
https://query.wikidata.org/bigdata/ldf?subject=http%3A%2F%2Fwww.wikidata.or…
Is this a bug or a limitation of a service?
With kind regards,
Maciej Gawinecki
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--
*Guillaume Lederrey* (he/him)
Engineering Manager
Wikimedia Foundation <https://wikimediafoundation.org/>