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Log of joint meeting of Johannes and Hannah to install Virtuoso and build an index for Freebase Easy

Installation

We followed the instructions on http://vos.openlinksw.com/owiki/wiki/VOS/VOSUbuntuNotes . The following command worked on galera (Ubuntu 18.04). I entered a password , as strongly recommended in the instructions (they said, it wouldn't work otherwise). But the message came that something went wrong with storing the password, but the subsequent steps worked anyway.

sudo apt install virtuoso-opensource

After the installation, the web page is immediately live under http://galera:8890

Index Build

On the console, just type the following (after copying the TTL file to the respective location). We first tried isqlw-vt (the Unicode-enabled variant), but that always returned an obscure error about a hostname that could not be resolved.

isql-vt
SQL> DB.DBA.TTLP_MT (file_to_string_output ('/local/data/virtuoso/fbeasy.ttl'), '', 'http://freebase-easy.cs.uni-freiburg.de');

The index build for Freebase Easy started on 18-01-2020 at 21:30. It aborted about 15 minutes later with the following error message:

*** Error 37000: [Virtuoso Driver][Virtuoso Server]SP029: TURTLE RDF loader, line 5684442: Invalid characters in angle-bracketed name at <4[pi]R

Asking SPARQL Queries

The Virtuoso SPARQL editor is available under http://galera:8890/sparql . A good check whether everything works is always the following query, which returns the number of triples. Note that this also works during bulk upload and can be used to track the progress of the upload.

SELECT COUNT(*) WHERE { ?s ?p ?o }