W3C home > Mailing lists > Public > semantic-web@w3.org > April 2007

Re: resources for network-based/hierarchical RDF store

From: Paul Gearon <gearon@ieee.org>
Date: Wed, 25 Apr 2007 06:02:54 -0500
Message-Id: <7B2F66AA-85AE-40D4-8FE5-5DE723370803@ieee.org>
Cc: semantic-web@w3.org
To: al@jku.at

Hi Andy,

While not network or hierarchical, the Mulgara database (http:// 
mulgara.org/) was written from the ground up to take RDF data and  
nothing else.  The database used to be called Kowari, and before that  
it was a commercial system called TKS (Tucana Knowledge Store).

To describe it briefly....

Mulgara does OK on 32 bit systems, but it scales really well on 64  
bit systems.  All joins are evaluated lazily, which removes memory  
limits, and complex queries don't cause any problems.  We have been  
slow getting SPARQL supported (though some simple SPARQL queries  
already work) but we support our own query language that predates  
SPARQL by several years and offers several more features.  These  
features include extra join operations, and insert/delete commands.   
There is also an SPI for plugging any kind of external data source in  
as a supplemental back-end.

We went through a quiet period after the company that started the  
original project shut down, but the project has been actively moving  
ahead for the past year, with a few new features and a lot of bug fixes.

Paul Gearon

On Apr 25, 2007, at 4:30 AM, Andreas Langegger wrote:

> Hash: SHA1
> Dear group members,
> most of currently available RDF triple store implementations (Jena,
> 3store, sesame, etc.) use relational database systems as the  
> underlying
> information system. Well, I guess this is because they are well known,
> have proven to scale and perform, you get existing features for data
> management, indexing, transactions, etc. and can use existing tools.
> However, are there any resources (papers/projects/links/...) where RDF
> storage in network/hierarchical databases is investigated? Would there
> be benefits?
> The bottlenecks with RDBMS are either huge joins over the same  
> table =>
> memory problem for large datasets or complex query processing which at
> the moment has to be done in the higher app level. There should be
> better support inside the DBMS in future like special join operations.
> If sb has pointers or comments, I'd appreciate!
> best regards,
> Andy
> - --
> -  
> ----------------------------------------------------------------------
> Dipl.-Ing.(FH) Andreas Langegger
> Institute for Applied Knowledge Processing
> Johannes Kepler University Linz
> A-4040 Linz, Altenberger Straße 69
>> http://www.faw.at
>> http://www.langegger.at
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Received on Wednesday, 25 April 2007 11:03:05 UTC

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