Nepomuk Without Files

Most people assume that if they switch off file indexing in Nepomuk, then all the nepomuk file services will get disabled. This is however not the case. Nepomuk consists of two services which are used to deal with files -

• Nepomuk File Watcher
• Nepomuk File Indexer

The Nepomuk File Indexer is responsible for calling the strigi plugins to index the files, whereas the FileWatch service is a general service that monitors file move, creation and deletion events. Even when the File Indexer does not exist, files may have metadata attached to them - Tags, Rating and Comments. We need the File Watcher to update our database whenever the url of a file changes.

The File Watcher internally uses a kernel API for file monitoring - inotify. This API, while quite easy to use, does not allow us to recursively watch directories, and more importantly, does not provide file move events unless we are watching both the source and the destination directory.

We need file move events in order to track a file’s url. This results in us having to create inotify watches for every single directory in your $HOME folder. This causes a large disk load on startup and is the cause of one of the critical bugs in Nepomuk. And we have no solution, until the kernel provides us with a better API.

Anyway, Nepomuk is being used in KDE PIM and Telepathy (development version), and none of those use cases have anything to do with files. It doesn’t make sense to subjugate others to pay the price of the file watcher, when they are not doing anything related to files. So, with that in mind, please add the following lines to your nepomukserverrc, if you do not care about files at all -

[Service-nepomukfilewatch]
autostart=false

Warning

With the Nepomuk FileWatch Service disabled, you’ll still be able to tag and rate your files, but these annotations will be lost if you move or rename the file.