How to reindex akonadi database without having to reconfigure?

Hi

I'm having the "Retrieving folder..." error message on every folder that 
contains an unread item. Akonadi fsck/vacuum/top/start no longer fixes the 
problem.
I have in the past followed the how to fix akonadi when there was a failed 
migration and that did all the work but it seemed like a hammer to crack a nut 
as you have to reconfigure kmail etc.

Is there a way to just delete the data and any related indexes to force a 
reindexing process?

I'm running out of ideas hence i hope this idea may help

Regards

Ian
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opensuse:tumbleweed:20170131
Qt: 5.7.1
KDE Frameworks: 5.30.0
KDE Plasma: 5.9.0
kwin5-5.9.0-1.1.x86_64
kmail2 5.4.1
Kernel:  4.9.6-1-default
Nouveau:  1.0.13_2.2