| Jheald added a comment. |
Another example, where such image searches may depend quite sensitively on query construction or query optimisation: Category:Grade I listed buildings in Bedfordshire.
One of the aims for faceted search is to be able to match (or even replace) the capabilities of Commons categories like this.
In fact the category already has a query on it, tinyurl.com/yan83fm2, that may be quite similar to what such an image search could/should produce; except that it has
?item wdt:P18 ?file
which is possible now, rather than
?file "depicts" ?itemwhich should become possible as soon as CommonsData supports the "depicts" statement.
A key part of the query is the bit generates the set of items to be depicted. This would presumably be pretty much unchanged with the move to CommonsData. But it is quite sensitive to the order the statements are taken in.
Taken in this order (forced by the query hint), the query executes in 2.9 seconds, which should be acceptable:
hint:Query hint:optimizer "None" . ?item wdt:P131+ wd:Q23143 . ?item wdt:P1435 wd:Q15700818 . ?item wdt:P31?/wdt:P279* wd:Q41176However, without the query hint the query is much slower, taking 50.5 seconds (for images from only 53 buildings) -- which I think people would find too long to be acceptable, and which might rapidly turn into an unsustainable server load, if very many people were trying to run queries like this at the same time.
This is why I worry quite a lot as to whether or not it will actually be possible to build faceted search in such a way that we can guarantee it will return with acceptable results in acceptable time.
Cc: Jheald, Ramsey-WMF, Cparle, Aklapper, Lahi, PDrouin-WMF, Gq86, E1presidente, Anooprao, SandraF_WMF, GoranSMilovanovic, QZanden, EBjune, Tramullas, Acer, V4switch, LawExplorer, Susannaanas, Wong128hk, Aschroet, Jane023, Wikidata-bugs, Base, matthiasmullie, aude, Ricordisamoa, Lydia_Pintscher, Fabrice_Florin, Raymond, Steinsplitter, Matanya, Mbch331
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