I thought I'd try KMail2 another try and I wiped out all my IMAP accounts and started over. I created a single IMAP-account for testing and I also set it to be offline when I quit KMail.

Well, testing didn't go so well (one of the reasons was that akonadiserver was/is constantly taking 35+% CPU), so I quit KMail.

After that akonadiserver just keeps going and still eating CPU. I killed the process, but after a few seconds another akonadiserver process is started and it starts eating my CPU again.

I took a look at akonadiconsole and my IMAP account is marked as offline in there. I also don't see anything else that could feed Akonadi or smth (Nepomuk is disabled too).

How can I find out what is Akonadi so busy with?

Is your calendar plasmoid donfigured to show events? That may be the cause (Akonadi does not start automatically, it only does when something requests it).

Nope, I don't have calendar plasmoid. Neither is KOrganizer reminder daemon running. There's notes' plasmoid though - it uses Akonadi as well, doesn't it?

Anyway, I can get rid of Akonadi by "akonadictl stop", but I wonder why does it eat my CPU? When I left work yesterday, I thought I'll give it the whole evening and night for getting straight whatever it's doing, but after coming back in the morning, Akonadi was just as busy as 16 hours ago.

Is there a way to check what Akonadi is currently doing?

I'd guess the Akonadi console (/usr/bin/akonadiconsole) would be the tool to use http://techbase.kde.org/Projects/PIM/Ak ... ment_Tools

Akonadi Console is purely a development tool. It allows you to view and change internal data structures of Akonadi. You should only change data in here if you know what you are doing, otherwise you risk damaging or losing your personal information management data.
Use at your own risk!

I'd look at the debugger, scheduler and tracker tabs, all of which need to be enabled.

So I have tried it sometimes, but haven't found out anything useful - job tracker does not show anything etc, but Akonadi is busy.