I'm having issues trying to update/upgrade to 42.2. Akonadi gets hung up
trying to process email messages - hangs one cpu (of 8) at 100% for up to 5
minutes. The system will then simply continue or Akonadi/kmail will crash
completely. I see similar issues all the way back to 13.1 but the
occurrences are more frequent and have much greater impact with the 42.2.
The randomness is that there appears no consistent sequence of events
leading to the crash (at least none that I've been able to spot) after
recreating the updated system from the same base system several times.

Is there a way to force a re-index of the email database or do a manual
index of the emails?