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Re: On Parameters

From: Steve Harris <steve.harris@garlik.com>
Date: Wed, 25 Mar 2009 22:15:56 +0000
Message-Id: <775F3DA2-F634-48A8-BD35-0871C7EC66FC@garlik.com>
To: SPARQL Working Group <public-rdf-dawg@w3.org>
On 25 Mar 2009, at 20:50, Orri Erling wrote:
> All
>
> It seems to me that the whole topic is readily ameanable to  
> experiment.  The
> rest of the post is concerned with that.
> As a preamble, I would say that update, expressions, aggregation,  
> group by
> and subselects are quite a bit   more important than parameters.

I agree, and that's why I gave my -1 to parameters. I like the feature  
(though not as an optimisation), but the group doesn't have time to  
standardise 6 features (well at least), so parameters does not make  
the cut for us.

> If one makes an online service that must do the same query over and  
> over,
> like showing a dashboard, chances are that it is not done with the
> SPARQL protocol.  Instead, it will be a database specific CLI which  
> may have
> parameters, stored procedures, whatever.  How do you go about
> this at Garlic?  Certainly, OpenLink applications that query RDF do  
> not have
> a web server talking to  a triple store over  SPARQL  protocol.

We have two systems that use SPARQL protocol (with a more efficient  
result format) and one that uses an internal protocol.

Our optimiser startup time is sufficiently short, and the queries  
sufficiently complex (in the optimised protocol case) that we would  
not get a significant gain from treating this as an optimisation.

For the systems that use the SPARQL protocol over HTTP the setup and  
teardown cost of the HTTP protocol outweighs the time take to prime  
the optimiser by a huge margin.

> We could say with some justification that we leave such cases to  
> vendor
> CLI's, where something like the Jena query execution API, also
> supported byOpenLink,  is the analog of JDBC/ODBC.

Indeed, and I'm in favour of that. We don't do it currently, but we  
will in the future. It doesn't require work by this working group at  
this time.

- Steve

-- 
Steve Harris
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Received on Wednesday, 25 March 2009 22:16:33 GMT

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