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Re: Introducing myself - SOA organised with RDF

From: Richard Newman <r.newman@reading.ac.uk>
Date: Wed, 15 Aug 2007 22:51:12 -0700
Message-Id: <36762BCB-F59B-4436-8E30-0D485E98F232@reading.ac.uk>
Cc: semantic-web@w3.org
To: Frank Carvalho <dko4342@vip.cybercity.dk>

Hi Frank,

   Thanks for such an interesting introduction!

> With eXist I have built XQueries to list information of specific  
> interest,
> and others to enable browsing through the RDF graph. I have also  
> built an
> XQL-query to make forward chaining of the graph. Performance seems  
> to be an
> issue. If anybody knows how to tune XQuery and eXist, I would be  
> grateful.

   I would very much suggest using a dedicated RDF store (any one  
would do), rather than storing the XML serialization of the RDF graph  
in an XML database. You will gain the ability to run queries against  
the graph, rather than just one of its possible tree serializations,  
and your scalability problem goes away (for a while, at least).

> I have tried to use CWM, but it seems to crash when I use large  
> graphs. I
> have also made a simple gawk-script that can actually both make
> forward-chaining and backward-chaining very efficiently.

   cwm is not really designed for large-scale storage. Take a look at  
this list of alternative systems on the ESW Wiki:

<http://esw.w3.org/topic/ 
SemanticWebTools#head-805c63479c854babe4657d5184de605910f6d3e2>

   If you're dealing with large graphs (>100M triples), you might  
find this list useful.

<http://esw.w3.org/topic/LargeTripleStores>

   If you need to do reasoning on large graphs, your choices are more  
limited, and the kind of reasoning you want to use might dictate your  
solution. (I won't reveal any biases on a public forum :D)

-R
Received on Thursday, 16 August 2007 05:51:34 GMT

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