OpenLink Software is pleased to announce a new release of Virtuoso, Open-Source Edition, version 5.0.6.
On the RDF side, the bitmap intersection join has been optimized so that it is now typically twice as efficient as an equivalent nested loop join.
In some cases XML trees in the object position in RDF quads were incorrectly indexed, leading to failure to retrieve quads. This is fixed and should problems occur in existing databases, they can be corrected by simply dropping and re-creating an index.
The cost model has been further tuned. We have run the TPC-H queries with larger databases and have profiled it extensively. There are improvements to locking, especially for concurrency of transactions with large shared lock sets, as is the case in the TPC-H queries. The rules stipulate that these have to be run with repeatable read. There are also optimizations for decimal floating point.
As part of the completion of our Business Intelligence extensions to SPARQL (SPARQL-BI), we released a sampling of TPC-H queries translated into SPARQL, and integrated this into the standard demonstration database. The new demo database provides a live sample of the TPC-H schema and instance data in linked-data form, complete with SPARQL-BI variants of the standard TPC-H queries. Relational-to-RDF model-mapping is now demonstrably mature and robust enough for enterprise-grade business-intelligence applications.
For more details, see the release notes:
Virtuoso Open Source Edition Links:
Home Page: http://virtuoso.openlinksw.com/wiki/main/
Download Page: http://virtuoso.openlinksw.com/wiki/main/Main/VOSDownload
OpenLink Data Spaces Links:
Home Page: http://virtuoso.openlinksw.com/wiki/main/Main/OdsIndex
SPARQL Usage Examples (re. SIOC, FOAF, AtomOWL, SKOS):
OpenLink AJAX Toolkit (OAT) Links:
Project Page: http://sourceforge.net/projects/oat
Live Demonstration: http://demo.openlinksw.com/oatdemo
Interactive SPARQL Demo: http://demo.openlinksw.com/isparql/
RDF Browser Demo: http://demo.openlinksw.com/rdfbrowser