On 9/5/10 1:34 AM, Olivier Berger wrote:
Hi.
Is it possible to use virtuoso as a SPARQL proxy/cache for another
SPARQL endpoint ?
We have already deployed a D2R server in order to provide RDF out of a
RDBMS (postgres). But queries tend to explode (maybe our mapping's
fault) and render data inaccessible (D2R and or Postgres
crashed/stuck/busy or whatever). Data in the postgres DB is constant, so
we may as well have some RDF cache instead of replaying the SQL queries
allover again.
I'm thinking of using Virtuoso sponger to fetch RDF triples from the D2R
SPARQL endpoint (with DESCRIBEs ?), and cache in turn (and even do
reasoning maybe). Then we would just have to switch our SPARQL queries
over to Virtuoso instead of D2R.
Is this possible and are there docs explaining how to plug Virtuoso
(sponger?) to another SPARQL endpoint ?
I think another option would be to port our mapping to Virtuoso so that
it does the job to query the Postgres DB and produce triples, but as the
mapping is a bit complex, I'd like to try a faster way.
Also, such a setup may allow us to mix in virtuoso data coming from
several such D2R (ou other) SPARQL endpoints for richer/larger queries.
Thanks in advance.
The commercial edition of Virtuoso includes a high-performance and
scablable RDF Views feature of ODBC and JDBC accessible data sources. In
short, to date, this delivers the fastest performance you can get when
executing SPARQL queries (even exceeds the native quad store). In the
next edition of V6 we've added materialization and syncing to this RDF
Views feature which basically materializes the RDF Views in the quad
store, and then keeps them in sync via sophisticated incremental
snapshot replication. An addition benefit of this new effort is the
ability to perform faceted style browsing over massively large data sets
originating from one or several (heterogeneous) ODBC or JDBC accessible
relational data sources.
Links:
1. http://virtuoso.openlinksw.com/dataspace/dav/wiki/Main/VOSSQL2RDF --
RDF View Feature page
2.
http://virtuoso.openlinksw.com/dataspace/dav/wiki/Main/VirtRdb2RDFViewsGeneration#OneClickLinkedDataGenerationAndDemployment
-- RDF View Generation via HTML Wizard
3. http://www.youtube.com/watch?v=bj7AbJ0ZYCk -- Video screencast
showing use of HTML Wizard to generate RDF Views .
--
Regards,
Kingsley Idehen
President& CEO
OpenLink Software
Web: http://www.openlinksw.com
Weblog: http://www.openlinksw.com/blog/~kidehen
Twitter/Identi.ca: kidehen
