Nepomuk

Nepomuk since KDE 4.4.2 is based on the Virtuoso backend. That is written in C++ as opposed to Redland or Sesame2, which were both java apps. This results in a much higher indexing speed and drasticaly smaller database. With KDE 4.4.3 some bugs in the creation of the database were fixed and now it seems to work flawless. Please set up Nepomuk in Systemsettings – Advanced – Desktop Search to your liking. Please give it enough ram if you can afford it, that will additionaly speed up things. I gave it 250 MB for /home containing mails in the 10.000 region and heaps of PDF and other text material. Also /etc and /var gets indexed. You can really finegrain down to the single file what you want indexed and also add more excludes than the ones predefined.

After the initial indexing is done by Strigi (which can take a while, depending on the size and amount of files to index) desktop searches can be performed in Dolphins search field. Another way is using KRunner (Alt-F2) which seems to not work properly yet. My usual searchpattern is for information in mails, either mails sent to or received from a person/mailing list or mails containing certain words. Besides that i search IRC logs (i have tons since the days of Kanotix), logs in /var ot stuff in /etc. Specialy for mails and logs i know no faster and more refined way to retrieve information. Let me make this clearer with a picture:

To the upper right you can see the searchfield with my searchpattern ‘patchkabel’. In the line below you could refine your search.  On the right side you can see it has found 3 mails, 1 PDF and one text file matching my pattern. On the right side you see the ‘Informations’ sidebar (F11 shows/hides it). That shows valuable extra information like other mails connected to the person or topic, character/wordcount, references, dates and more. All these can be opended right from the sidebar clicking on the links. You can create more meaningful output there if you tag, rate, and comment important files, mails, pictures etc. (tagging a picture with a keyword in a mail/text/whatever e.g.) and so over time get a real semantic desktop. In the future it does not matter what directory structure you have if you tag things in the right way.

Also have a look at an intersting blogpost [2] by Aaron Seigo from today on Nepomuk and what its planned to be in the future. 

Akonadi 

Where the usecases for Nepomuk are rather straightforward, Akonadi [3] will reveal its true power only over time as it is integrated only partialy in KDE Pim so far. Basicaly it will be kind of a local groupware server. In KDE 3 every application had the power over its own ressources which led to sometimes more than one app having the framework to, for instance deal with contacts, like KAdressbook and Kopete. The idea with Akonadi is to have one central instance [4] dealing with all KDE PIM ressources, be they your adressbook or a google calender, keep them synchronised and searchable on different computers and from all KDE apps where this makes sense. KDE 4.4.3 only incorporates KAdressbook so far, 4.5 will also take charge over Kmail. Unfortunately the implementation  in KDE 4.4.3 still has some Mysql bugs that were already present in 4.4.2.

Now lets get to the nitty gritty: How do we get rid of those bugs and have a working Akonadi?

First of all, no matter if you run KAdressbook standalone or with Kontact you might get something like:

A quick fix for this is, logged in as user:

rm -r $HOME/.local/share/akonadi 

akonadictl start

mysql_install_db --datadir=$HOME/.local/share/akonadi/db_data/ 

mysql_upgrade --socket=$HOME/.local/share/akonadi/db_misc/mysql.socket 

akonadictl stop

akonadictl start

Akonadi Control: running

Akonadi Server: running

Akonadi Server Search Support: available (backend: Virtuoso)

If the last line shows ‘not available’, check if virtuoso-minimal is installed.

You should now have a working instance of Akonadi and, when accessing your adressbook, should see a 3-fold window. In the one to the left, right-click and import an adressbook. You most likely want to navigate to: /home/USER/.kde/share/apps/kabc/stdvcf. If this does not work as expected please post on the forum with your issues so we can look into them and update this blog post over time.

userbase.kde [5] is also a good ressource for issues with Akonadi.

I will update this blog as soon as KDE 4.5 hits us with Kmail integration in Akonadi.