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    <p>How many triples on those RDF files ? I have tested <code>rdflib</code> and it won't scale much further than few tens of ktriples - if you are lucky. No way it really performs well for files with millions of triples.</p> <p>The best parser out there is <code>rapper</code> from <a href="http://librdf.org/" rel="noreferrer">Redland Libraries</a>. My first advice is to not use <code>RDF/XML</code> and go for <code>ntriples</code>. Ntriples is a lighter format than RDF/XML. You can transform from RDF/XML to ntriples using <code>rapper</code>:</p> <p><code>rapper -i rdfxml -o ntriples YOUR_FILE.rdf &gt; YOUR_FILE.ntriples</code></p> <p>If you like Python you can use the <a href="http://librdf.org/bindings/" rel="noreferrer">Redland python bindings</a>:</p> <pre><code>import RDF parser=RDF.Parser(name="ntriples") model=RDF.Model() stream=parser.parse_into_model(model,"file://file_path", "http://your_base_uri.org") for triple in model: print triple.subject, triple.predicate, triple.object </code></pre> <p>I have parsed fairly big files (couple of gigabyes) with redland libraries with no problem.</p> <p>Eventually if you are handling big datasets you might need to assert your data into a scalable triple store, the one I normally use is <a href="http://4store.org" rel="noreferrer">4store</a>. 4store internally uses redland to parse RDF files. In the long term, I think, going for a scalable triple store is what you'll have to do. And with it you'll be able to use <a href="http://www.w3.org/TR/rdf-sparql-query/" rel="noreferrer">SPARQL</a> to query your data and <a href="http://www.w3.org/TR/sparql11-update/" rel="noreferrer">SPARQL/Update</a> to insert and delete triples.</p>
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    1. COThanks for reply, I'm using ntriples, but wanted to use alignments as well (It would be really cool to have confidence values on mappings, is it possible to have them in ntriples?). Not sure about number of entries but size is around 1Gb each file (for now 8 files total, but can grow up to 100). Probably now I'll start migrating to 4store + Redland ...
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    2. COAlignments in ntriples ? if they can be expressed in RDF they can also be expressed in ntriples. And Yes, for the number of files and sizes that you mention ... definitely go for 4store. You'll find valuable help at http://groups.google.com/group/4store-support
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    3. CO4store sounds a bit more complex than I thought, I just wanted to run it on my laptop for student project I'm working on. There is chance to consider only subset of the triples, do you know what are the maximum capabilities of using Redland only without 4store?
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