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From Reto Bachmann-Gmuer <reto.bachm...@trialox.org>
Subject Re: A question about Jena Sparql Engine and the TDB Store
Date Fri, 18 Mar 2011 08:28:52 GMT
On Thu, Mar 17, 2011 at 5:18 PM, Olivier Grisel <ogrisel@nuxeo.com> wrote:

> On 17 March 2011 16:37, Hasan Hasan <hasan@trialox.org> wrote:
> > Hi Olivier
> >
> > Indeed, this "fastlane" support in executing sparql queries, where the
> > underlying triple store is jena, is something that still on our to do
> list.
> > However, if you would like to contribute and provide a patch, that would
> be
> > really appreciated.
> > Not sure about the effort needed to get the native TDB Dataset
> encapsulated
> > in the TripleCollection though. There may be some other wrappers
> in-between
> > which are inserted to provide security and locking mechanisms
>
> Ok thanks for your reply. Security and locking checks apart, making
> the jena sparql engine able to fetch a TdbDataset instead of the
> generic TcDataset wrapper would require to introduce a new dependency
> between rdf.jena.tdb.storage and rdf.jena.sparql one way or another,
> maybe moving the TcDataset class as an interface in the
> rdf.jena.commons instead to avoid cyclic or unwanted dependencies.
>
No there must not be such a dependency. The solution I think should rougly
look like this: TcProvider can Implement an additional Subinterface (say
SparqlTcProvider) allowing to pass Sparql-queries to them. If a sparql query
affects only graphs provided by the same SparqTcProvider the the query is
forwarded to that provider, otherwise the current process aplies.


>
> Also it would be great to have support for fined grained support for
> default and named graph in SPARQL queries with named graph mapped to
> the Clerezza graph ids used by the TcProvider. In jena this seem to be
> provided by:
>
>  http://www.openjena.org/wiki/TDB/DynamicDatasets
>
> I wonder if this compatible with the current directory structure
> implied by the TdbTcProvider#getMGraph implementation.
>
I agree. Possibly changes in tdb.storage are needed.

Cheers,
Reto

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