Well on those systems where I do not use Akonadi and switch to SQLite3.
Please do not do this without having a good reason to do it, in case you
actually use Akonadi.
There is potential data loss – i.e. loosing mails, appointments,
contacts – in there, since Akonadi is unfortunately not just a read
cache, but a time-limited – or unlimited in case of a certain
conditation – write cache where things may end to be stored just in the
database for a limited or even an unlimited time ("item without RID"
message in akonadictl fsck).