[developers] semantic representations in RDF

[Stephan Oepen]

> Note how in the local instance, the pattern `_fi*` is transformed into an enumeration of the predicates found in the dataset:
>
> { ?100 eds:predicate "_fight_n_1"^^xsd:string } UNION { ?100 eds:predicate "_fight_v_1"^^xsd:string }
>
> But in the SPARQL on the delph-in.net server, the pattern is transformed into a regex filter
>
> regex(?100TEXT, "^_fi.*$”)

actually, this kind of expansion (a query optimization, using a
first-line lucene index of known strings) appears to be sensitive to
the size of the expansion set.  i can confirm that (on the reference
WSI instance) '_fi*' is matched using a (slow) regular expression
(filter), whereas '_fight*' gets expanded; see the attachment.
presumably you just have a smaller index in your local instance?

the original WSI developer was an experienced enterprise coder, so i
am not surprised (but impressed) he implemented it this way:
presumably there is a tipping point in efficiency by querying with a
disjunction of specific strings vs. filtering candidate matches using
a regular expression ...

cheers, oe
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