I installed akonadi-backend-sqlite and uninstalled
akonadi-backend-mysql, which was possible. Now akonadi does not start.
If there is a implicit dependency, that the mysql backend at least needs
to be installed, its no package dependency of akonadi-server,
akonadi-backend-sqlite or any of the akonadi clients.
So either its a bug, that the sqlite backend cannot be used, or there is
a missing dependency, which is needed to use the sqlite backend.

In article <20131008181632.11688.98454.reportbug__33918.3388663971$1381256486$gmane$org@nemesis.laxu.de> you wrote:
postgresql or sqlite backend you need to manually change akonadi configuration
to use that connection.

This is documented in:
/usr/share/doc/akonadi-backend-sqlite/README.Debian.gz

Also sqlite and postgres are considered experimental backends, this is only
fixed in akonadi 1.10.2.

I'd like to add a few notes to this bug. I installed just the Sqlite
backend as I don't want MySQL on this machine. This worked fine on squeeze
and wheezy, but I recently upgraded to jessie and every time I logged into
a KDE session I would get a dialog box saying that Akonadi was "upgrading
resources" which would stay there for a minute or so without progress. Upon
further investigation I discovered that the Akonadi server wouldn't start
because it was looking for MySQL:

$ akonadictl start
[...]
mysqld not found. Please verify your installation
[correct, it's not installed on this machine]
[more error messages and a stack trace]
ProcessControl: Application 'akonadiserver' returned with exit code 255
(Unknown error)
[the above part repeats three more times]
"akonadiserver" crashed too often and will not be restarted!

Maximiliano Curia wrote:

Manually? Are you joking? This is KDE, not bash with more colors.

...which says, among other things:
"Just install the backend package which is the most appropriate for your
setup [...]"

That's what I did. Again, if the MySQL backend is required for the package
to work, why isn't there a dependency? That's what the original bug report
was asking. Either Akonadi *needs* the MySQL backend, therefore a
dependency is required, or the fact that Akonadi won't start without the
MySQL backend is a bug that needs fixing. Just select the first available
backend and be done with it. By the way, if you just write:

  [%General]
  Driver=foo

...into ~/.config/akonadi/akonadiserverrc, then the control panel will
start and let you set the configuration. It's funny that an invalid
configuration works better than a valid configuration without the backend.

Truth be told, the real question for me is that I don't want Akonadi on my
system, but it is a dependency of several core KDE packages (I didn't track
which ones exactly) so it can't be removed. I "solved" the problem by
dpkg-redirect'ing /usr/bin/akonadi* and /usr/lib/libakonadi
out of the way, so package dependencies are satisfied. The KDE session
starts without errors and every piece of KDE that I'm actually interested
in runs fine, so I guess Akonadi is not really required. I have no problem
if you won't fix the Akonadi package dependencies as I've now made sure it
won't affect me, but I'd really like if someone fixes the other KDE
packages' dependencies so I can remove Akonadi altogether.

On Wednesday 27 November 2013 00:18:55 Flavio Stanchina wrote:
[snip]

Please be respectful. Maxy knows what he's telling you.
And no, we are not joking. You have to set it up manually. If you want to have
any other option, please ask upstream to implement it by filling the
appropriate bug report upstream.

Noted, will have to be fixed.

And then you are barking against the wrong people. Ask upstream to not set a
default and show that same config option from the beginning.

Sorry but that's not possible. Akonadi is needed by many parts and it's usage
will probably continue to grow. We maintainers need to set up things as
upstream wants. If you don't like that, ask upstream, not us.

On Wednesday 27 November 2013 00:18:55 Flavio Stanchina wrote:
[snip]

Please be respectful. Maxy knows what he's telling you.
And no, we are not joking. You have to set it up manually. If you want to have
any other option, please ask upstream to implement it by filling the
appropriate bug report upstream.

Noted, will have to be fixed.

And then you are barking against the wrong people. Ask upstream to not set a
default and show that same config option from the beginning.

Sorry but that's not possible. Akonadi is needed by many parts and it's usage
will probably continue to grow. We maintainers need to set up things as
upstream wants. If you don't like that, ask upstream, not us.