[Rdfapi-php-interest] Scalability and performance

[Markus <ma...@ai...>]

Hi.

We consider using RAP as a quadstore for Semantic MediaWiki (see=20
http://wiki.ontoworld.org). In the long run, we are interested in=20
inferencing, but for now Wikipedia-size scalability is most important. Are=
=20
there recent evaluations concerning the performance of the different storag=
e=20
models? In particular, we are interested in scalability of the following=20
functions:

1 SPARQL queries:
 1.1 general performance
 1.2 performance of "join-intensive" queries (involving long chains of=20
     triples)
 1.3 performance of datatype queries (e.g. selecting/sorting results by some
     xsd:int or xsd:decimal)
 1.4 performance for partial result lists (e.g. getting only the first 20)
2 simple read access (e.g. getting all triples of a certain pattern or RDF=
=20
  dataset)
3 write access
 3.1 adding triples to an existing store
 3.2 deleting selected triples from the store
4 impact of RDF dataset features/named graph functionality

=46or inclusion in Wikipedia, dealing with about 10 Mio triples split into =
1 Mio=20
RDF datasets is probably necessary. We are working on useful update and=20
caching strategies to reduce access to the RDF store, but a rather high=20
number of parallel requests still is to be expected (though normal reading =
of=20
articles will not touch the store). It would also be possible to restrict t=
o=20
certain types of queries if this leads to improved performance.

We currently use RAP as an RDF parser for importing ontologies into Semanti=
c=20
MediaWiki. For querying our RDF data, we consider reusing an existing=20
triplestores such as Redland or RAP, but also using SQL queries directly.=20
Java toolkits are not an option since Wikipedia requires the use of free=20
software (and free Java implementations probably don't support current RDF=
=20
stores).=20

I can imagine that one can already find performance measures for RAP somewh=
ere=20
on the web -- sorry if I missed this.

Best regards,

Markus

=2D-=20
Markus Kr=F6tzsch
Institute AIFB, University of Karlsruhe, D-76128 Karlsruhe
ma...@ai...        phone +49 (0)721 608 7362
www.aifb.uni-karlsruhe.de/WBS/     fax +49 (0)721 693  717