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Re: The truth about SPARQL Endpoint availability

From: Hugh Glaser <hg@ecs.soton.ac.uk>
Date: Sat, 5 Mar 2011 13:49:58 +0000
To: Andrea Splendiani <andrea.splendiani@bbsrc.ac.uk>
CC: Pierre-Yves Vandenbussche <py.vandenbussche@gmail.com>, "public-lod@w3.org" <public-lod@w3.org>, SW-forum <semantic-web@w3.org>, "semanticweb@yahoogroups.com" <semanticweb@yahoogroups.com>
Message-ID: <EMEW3|0c58357a74baf31225431db884590194n24DoN02hg|ecs.soton.ac.uk|F5D755D8-26DB-44E7-ADE3-3AEC5D345317@ecs.soton.ac.uk>
NIce idea, but,... :-)

SELECT (count(*) as ?c) WHERE {?s ?p ?o}

is a pretty anti-social thing to do to a store.
At best, a store of any size will spend a while thinking, and then quite rightly decide they have burnt enough resources, and return some sort of error.

For a properly maintained site, of course, the VoiD description will give lots of similar information.
Best
Hugh

On 5 Mar 2011, at 13:06, Andrea Splendiani wrote:

> Hi, very nice!
> I have a small suggestion:
> 
> why don't you ask "count(*) where {?s ?p ?o}" to the endpoint ?
> Or ask for the number of graphs ?
> Both information, number of triples and number of graphs, if logged and compared over time, can give a practical view of the liveliness of the content of the endpoint.
> 
> best,
> Andrea Splendiani
> 
> 
> Il giorno 28/feb/2011, alle ore 18.55, Pierre-Yves Vandenbussche ha scritto:
> 
>> Hello all,
>> 
>> you have already encountered problems of SPARQL endpoint accessibility ?
>> you feel frustrated they are never available when you need them?
>> you develop an application using these services but wonder if it is reliable?
>> 
>> Here is a tool [1] that allows you to know public SPARQL endpoints availability and monitor them in the last hours/days. 
>> Stay informed of a particular (or all) endpoint status changes through RSS feeds.
>> All availability information generated by this tool is accessible through a SPARQL endpoint.
>> 
>> This tool fetches public SPARQL endpoints from CKAN  open data. From this list, it runs tests every hour for availability.
>> 
>> [1] http://labs.mondeca.com/sparqlEndpointsStatus/index.html
>> [2] http://ckan.net/
>> 
>> Pierre-Yves Vandenbussche.
> 
> Andrea Splendiani
> Senior Bioinformatics Scientist
> Centre for Mathematical and Computational Biology
> +44(0)1582 763133 ext 2004
> andrea.splendiani@bbsrc.ac.uk
> 
> 
> 

-- 
Hugh Glaser,  
              Intelligence, Agents, Multimedia
              School of Electronics and Computer Science,
              University of Southampton,
              Southampton SO17 1BJ
Work: +44 23 8059 3670, Fax: +44 23 8059 3045
Mobile: +44 78 9422 3822, Home: +44 23 8061 5652
http://www.ecs.soton.ac.uk/~hg/
Received on Saturday, 5 March 2011 13:52:15 UTC

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