Hi Thanks for this. I've read the chapter in the book and now I'm not sure if I misunderstand your reply or you've only addressed half of the problem.
I'm not worried about the performance of the spatial search in isolation - that's 97ms which is fine. The text search on its own takes a bit longer but that's acceptable, too. It's when I put the spatial and text *together* that query time increase by 10-30 times. That's the bit I don't understand and would like some help with. Is there a SPARQL query formulation that can "AND the indexes" rather than retrieving one set and looping through to retrieve the matches individually on the other. (Which is my guess as to how it works). Thanks for your help so far. Mark Technology Lead, Iotic Labs [email protected] https://www.iotic-labs.com On 18/12/15 18:59, Marco Neumann wrote: > it's a common spatial access method latency in paticular for small > data sets. you can try a mbr range query instead. > > see Chapter 13 Managing Space and Time in Semantic Web Programming by > John Hebeler et. al.. 2009 > > On Fri, Dec 18, 2015 at 10:13 AM, Mark Wharton > <[email protected]> wrote: >> Hi Jena users. >> >> I'm having performance problems with a query that uses text and location >> search >> >> The query is roughly this: >> >> >> SELECT ?score ?ent >> WHERE { >> ?ent spatial:nearby(51.507999420166016 -0.10999999940395355 >> 70.01807880401611 'km') . >> (?ent ?score) text:query ('environment' 'lang:en') . >> ?ent rdf:type iotic:Entity . >> } >> >> >> There are about 450 entities in that radius >> There are about 2200 entities with environment in their rdfs:comment >> >> The query takes 5 seconds. >> >> I've tried this: >> Commenting out the text predicate the query takes 97 ms >> Commenting out the spatial predicate the query takes 438 ms >> Swapping the spatial and text predicates it takes 15 seconds >> >> >> My question is this... It looks like the query is separately getting >> the results of the first two predicates and merging (somehow) to find >> the intersection. Is there a formulation which will intersect the two >> sets faster? >> >> Many TIAs, >> >> Mark >> -- >> Technology Lead, Iotic Labs >> [email protected] >> https://www.iotic-labs.com > > >
