query-48e8c0a1b447e52fb6c512cec76e7410

Why does this very basic query timeout?

Use at

https://query.wikidata.org/sparql

PREFIX pr: <http://www.wikidata.org/prop/reference/>
SELECT ?ref ?refURL WHERE {
  ?ref pr:P854 ?refURL .
  FILTER (CONTAINS(str(?refURL),'philatlas.com')) .       
} LIMIT 20

Query found at

https://www.wikidata.org/wiki/Wikidata:Project_chat/Archive/2020/06

graph TD classDef projected fill:lightgreen; classDef literal fill:orange; classDef iri fill:yellow; v2("?ref"):::projected v1("?refURL"):::projected f0[["contains(str(?refURL),'philatlas.com')"]] f0 --> v1 v2 --"pr:P854"--> v1