Tuesday, December 21, 2004

Just Ask for Help

Came across Yet Another RDF Store: Perfect Index Structures for Storing Semantic Web Data With Contexts "We tried to install Kowari, but failed to get a running version. In one of our installations, inserting a 1 MB N-triples file via the Jena interface resulted in 30 minutes processing time before the process threw an exception because of a full disk (there were 200MB disk space available before starting the Kowari server). On another installation, we got a core dump of the JVM when running Kowari. Therefore we concentrated in our efforts on Sesame 1.1RC2 and Redland 0.9.18."

This is the first record of anyone having a problem with Kowari in this respect and without any idea of what version of Kowari or Java or the OS or anything else I went and downloaded their example code. Using Kowari 1.0.5 (they mentioned Sesame 1.1RC2 which was released after 1.0.5) with the given code you get an exception as NTriples is not supported as a parameter. NTriples is a subset of N3. So this code doesn't work. However, if the code is modified so that the last lines become:
  model.read(new FileReader(file), file.toURI().toString(), "N3");
model.close();
database.close();

And run the code you get:
...
INFO [main] (AbstractDatabaseSession.java:699) - Loading
file:/.../University1_0.nt into rmi://.../server1#camera
INFO [main] (AbstractDatabaseSession.java:770) - Loaded 7304
statements
...

If people have any problems running Kowari, before they write it up as a paper maybe they should ask someone how to get it running first. Although, this isn't the first time.
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