About Strigi, Soprano, Virtuoso, CLucene, and Libstreamanalyzer

There seems to be a lot of confusion about the parts that make up the Nepomuk infrastructure. Let me shed some light.

Soprano is the RDF data storage and parsing library used in Nepomuk. Soprano provides a plugin for Virtuoso which is mandatory and requires libiodbc. It does NOT work with unixODBC (It compiles but simply does not work due to some extensions in libiodbc required for RDF data handling). In addition to the Virtuoso plugin Nepomuk requires the Raptor parser plugin and the Redland storage plugin for ontology import.

CLucene is not required in Nepomuk anymore. It has been used for full-text indexing in early versions of KDE but is superseded by the fullt-text indexing functionality of Virtuoso. Consequently the Soprano clucene module is not required anymore and development has effectively been stopped. It will most likely not be part of Soprano 3 (unless someone interested steps up and does the required work).

Virtuoso is a full-blown SQL server with a powerful RDF layer on top. OpenLink, the company developing Virtuoso, maintains an open channel of communication to the Nepomuk developers and introduced a “lite” mode for us (please no comments on how it still is not “lite”). Virtuoso 6.1.3 is the current version. It has a unicode bug which can be fixed by applying the patch attached to KDE bug 271664. Virtuoso 6.1.4 will be released soon and contains several fixes to bugs reported by me. An update is highly recommended.

Libstreamanalyzer and libstreams are libraries which are part of the Strigi project. In addition the Strigi project contains strigidaemon, an alternative scheduler for indexing files which is based on CLucene and not used by Nepomuk. I asked the maintainer of Strigi once to split libstreams and libstreamanalyzer into their own independently released packages. He refused which is understandable seeing as he has little time for Strigi as it is. As a consequence I advise packagers to either use libstreamanalyzer from git master or the latest tag instead of using released tarballs.

I think that is all. If I missed something please comment and I will update the post.

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