Version: (using KDE 4.4.0) OS: Linux Installed from: Archlinux Packages To test this is have created a text file in my home directory named "abcdef" with the content "foobar". I use dolphin's search bar to do the searches. When I search for "abc" it shows no results. When I search for "abcd", "abcde" or "abcdef" it correctly finds the file. Likewise, when I search for "foo", it shows nothing. As soon as I enter more characters (from "foob" to "foobar") it finds the file. It seems nepomuksearch just ignores search terms with 3 characters or less which I don't think is a good idea.
I can confirm that this behaviour showed up after 4.4 RC3, it worked perfectly with 3 characters before and fails now in the final release.
Virtuoso 6.1 has a minimum 4 char for full text searches. V5 had 3 chars. I will look into this to see what can be done about that.
Fixed with commit 1212019 in 4.6 and trunk.
I can confirm that this is fixed in KDE SC 4.6 RC2. Thank you, this made Nepomuk so much more useful for me since my employer happens to be named by only 3 letters! :)