CODEWITHSUNDEEP
sparqlwikidata
whirish
whirish

Reputation: 470

Path matching inside a VALUES clause

I'm trying to perform path matching inside a VALUES clause in sparql in order to match all instances and subclasses of both battles and sieges in wikidata. The following request repeatedly times out. 

SELECT DISTINCT ?battle ?battleLabel WHERE {
  {
    SERVICE wikibase:label { bd:serviceParam wikibase:language "[AUTO_LANGUAGE],en". }
    VALUES ?type {wd:Q178561 wd:Q188055} ?battle (wdt:P31/wdt:P279*) ?type .
    ?battle rdfs:label ?queryByTitle.
    FILTER(REGEX(?queryByTitle, "saratoga", "i"))
  }
}

Upvotes: 1

Views: 88

Answers (1)

Stanislav Kralin
Stanislav Kralin

Reputation: 11469

It seems that VALUES, esp. in conjunction with /, confuses the Blazegraph's query optimizer in that case.

Use UNION instead of VALUES:

SELECT DISTINCT ?battle ?battleLabel WHERE {
    { ?battle wdt:P31/wdt:P279* wd:Q178561 }
    UNION
    { ?battle wdt:P31/wdt:P279* wd:Q188055 }
    ?battle rdfs:label ?queryByTitle.
    FILTER(REGEX(?queryByTitle, "saratoga", "i"))
    SERVICE wikibase:label { bd:serviceParam wikibase:language "[AUTO_LANGUAGE],en" }
}

Alternatively, disable the optimizer and specify explicit order:

SELECT DISTINCT ?battle ?battleLabel WHERE {
    hint:Query hint:optimizer "None" .
    VALUES ?type {wd:Q178561 wd:Q188055}
    ?subtype wdt:P279* ?type .
    ?battle wdt:P31 ?subtype .
    ?battle rdfs:label ?queryByTitle.
    FILTER(REGEX(?queryByTitle, "saratoga", "i"))
    SERVICE wikibase:label { bd:serviceParam wikibase:language "[AUTO_LANGUAGE],en" }
}

Upvotes: 2

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