Query on sindice SPARQL endpoint -

i tried make query on http://sparql.sindice.com/

prefix rev: <http://purl.org/stuff/rev#> prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> select * {  ?thing rdfs:label ?name .   ?thing rev:hasreview ?review .  filter regex(str(?name), "harlem", "i") } limit 10 

and returns 504 gateway time-out server didn't respond in time. i'm doing wrong? thanks.

you made query hard endpoint answer in timely fashion hence why got timeout response. note there website states following:

all queries time , resource limited. notice means sometime incomplete or no results. if happening or want run more complex queries please contact us

your query selects vast swathe of data , makes engine run regular expression on ever possible value extremely slow.

i believe sindice use virtuoso sparql implementation can cheat , use virtuoso specific full text query extension so:

prefix rev: <http://purl.org/stuff/rev#> prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> select * {   ?thing rdfs:label ?name .   ?thing rev:hasreview ?review .   ?name bif:contains "harlem" . }  limit 10 

however query seems timeout, if can add more conditions constrain query further have more chance of getting results in timely fashion.