I recently extended Fuseki to hook into a Solr index for geographic query for one of our linked data projects, and I'm happy with the results so far. It will open the door for us to build more sophisticated geographic visualizations. I have not extended Fuseki for Lucene/Solr based full text search, as we have a standalone Solr index for that, and a separate search interface (for general users) from the SPARQL query interface (for advanced ones).
It's definitely true that there are scaling limitations in SPARQL--just look at how often dbpedia and the British Museum SPARQL endpoint go down. Hardware is overcoming these limitations, but I still advocate a hybrid approach: using Solr where it is advantageous to do so, and then build focused user interfaces on top of SPARQL, leveraging the advantages of a triplestore in contexts other than search. We open up our SPARQL endpoint to the public, but by far more users interact with SPARQL through a HTML interfaces in several different projects without having any idea that they are doing so. We only have about a million triples in our triplestore (but this is going to grow enormously in less than two years, I think, as the floodgates are about to open in the world of ancient Greco-Roman coins), but the system has only gone down for about 2 minutes in the last 2.5 years, on a virtual machine with only 4GB of memory. Ethan On Fri, Dec 19, 2014 at 10:20 AM, Mixter,Jeff <mixt...@oclc.org> wrote: > > A triplestore is basically a database backend for RDF triples. The major > benefit is that it allows for SPARQL querying. You could imagine a > triplestore as being the same thing as a relational database that can be > queried with SQL. > > The drawback that I have run into is that unless you have unlimited > hardware, triplestores can run into scaling problems (when you are looking > at hundreds of millions or billions of triples). This is a problem when you > want to search for data. For searching I use a hybrid Elasticsearch (i.e. > Lucene) index for the string literals and the go out to the triplestore to > query for the data. > > If you are looking to use a triplestore it is important to distinguish > between search and query. > > Triplestore are really good for query but not so good for search. The > basic problem with search is that is it mostly string based and this > requires a regular expression query in SPARQL which is expensive from a > hardware perspective. > > There are a few triple stores that use a hybrid model. In particular Jena > Fuseki (http://jena.apache.org/documentation/query/text-query.html) > > Thanks, > > Jeff Mixter > Research Support Specialist > OCLC Research > 614-761-5159 > mixt...@oclc.org > > ________________________________________ > From: Code for Libraries <CODE4LIB@LISTSERV.ND.EDU> on behalf of Forrest, > Stuart <sforr...@bcgov.net> > Sent: Friday, December 19, 2014 10:00 AM > To: CODE4LIB@LISTSERV.ND.EDU > Subject: Re: [CODE4LIB] rdf triplestores > > Hi All > > My question is what do you guys use triplestores for? > > Thanks > Stuart > > > > ================================================================================ > Stuart Forrest PhD > Library Systems Specialist > Beaufort County Library > 843 255 6450 > sforr...@bcgov.net > > http://www.beaufortcountylibrary.org > > For Leisure, For Learning, For Life > > > > -----Original Message----- > From: Code for Libraries [mailto:CODE4LIB@LISTSERV.ND.EDU] On Behalf Of > Stefano Bargioni > Sent: Monday, November 11, 2013 8:53 AM > To: CODE4LIB@LISTSERV.ND.EDU > Subject: Re: [CODE4LIB] rdf triplestores > > My +1 for Joseki. > sb > > On 11/nov/2013, at 06.12, Eric Lease Morgan wrote: > > > What is your favorite RDF triplestore? > > > > I am able to convert numerous library-related metadata formats into > RDF/XML. In a minimal way, I can then contribute to the Semantic Web by > simply putting the resulting files on an HTTP file system. But if I were to > import my RDF/XML into a triplestore, then I could do a lot more. Jena > seems like a good option. So does Openlink Virtuoso. > > > > What experience do y'all have with these tools, and do you know how to > import RDF/XML into them? > > > > -- > > Eric Lease Morgan > > >
