Kmail 17.08.3-1.2 uses a single maildir with local folders and runs smoothly in the background. Suddenly the indexing agent starts up and writes several Gigabytes to disk. When restarted in akonadiconsole it sits idle in the background. Suddenly, sometimes after minutes, hours or even days it starts writing until restarted. Any idea?

Upgraded to Version 17.12.0-1.1. Quit kmail, stopped akonadi and deleted akonadi storage at .local/share/akonadi/. When invoking kmail again storage was rebuilt and local folders at .local/share/local-mail/ got indexed. Indexing created several GB of data in .local/share/akonadi/file_db_data/ These were later on deleted by kmail sitting in the background automatically. No more ***turbation by akonadi.