- From: Bob DuCharme <bob@snee.com>
- Date: Sun, 16 Dec 2012 22:30:11 -0500
- To: public-sparql-dev@w3.org
OK, that makes sense--a URI is inherently a key, so when indexed is
easier to look up, while a given literal value is not necessarily, right?
And congrats on the WG finishing up!
Bob
On 12/16/2012 4:41 PM, Andy Seaborne wrote:
>
>
> On 16/12/12 21:24, Bob DuCharme wrote:
>> Imagine that I have ten million triples, and these are two of them:
>>
>> <http://w> rdfs:label "my literal" .
>> <http://x> <http://y> <http://z> .
>>
>> I got the impression somewhere that this query
>>
>> SELECT ?s WHERE { ?s <http://y> <http://z> }
>>
>> would run faster than this one:
>>
>> SELECT ?s WHERE { ?s rdfs:label "my literal" }
>>
>> Is this true, and if so is it because URIs will always be indexed and
>> literals won't necessarily be?
>
> As far as I know, systems generally index literals - quite important
> for keys.
>
> Maybe there are many, many 'rdfs:label "my literal"' if it's not a
> key, which might make a difference, as much because there are more
> results.
>
>> Or is it all dependent on the
>> implementation?
>
> Yes.
>
> Andy
Received on Monday, 17 December 2012 03:30:33 UTC