SUMMARY

Occasionally KMail/Akonadi will during a sync(?) lose/remove the bodies of most messages. This issue in irreversible and spreads also to the server.

This is a grave issue, since data – whole messages – are lost. Only the headers remain.


STEPS TO REPRODUCE
1. make sure you have “download messages for offline use” enabled for the IMAP resourse
2. the e-mail sync – cannot predict or tell what triggers the issue with the sync TBH
3. eventually notice some e-mail is missing their bodies

OBSERVED RESULT

Many e-mails are missing their message body parts, but the headers seem intact.

The issue propagates to the servers (probably in the next sync), so now _everywhere_ these e-mails are lacking message bodies.

EXPECTED RESULT

Message bodies (and headers) for all e-mails to stay intact ;)

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: yes
(available in About System)
KDE Plasma Version: 5.24.3
KDE Frameworks Version: 5.91.0
Qt Version: 5.15.3

ADDITIONAL INFORMATION

I’m attaching a fuller log of how it happened this time (IRC log from #akonadi):

I’m having issues with Akonadi again.
In order to more properly fix some mess-up, I decided this time to create a new user and start from scratch. This will be a bit (but not super) long, I apologise in advance.
1) I renamed the old user to `backup_hook` (with `usermod --login`) and also its home to `/home/backup_hook`.
Previously the above user was `hook` and its home appropriately `/home/hook`.
2) I created a new user `hook` with a fresh, empty `/home/hook`.
3) I logged into Plasma as this new `hook`, with a fresh new Plasma set of defaults :)
4) I stared KMail and entered the credentials to my default e-mail account (quite a few e-mails there) through IMAP, I let them all download.
5) I started KOrganizer and entered my Nextcloud servers’s credentials
--- so far so good ---
6) I started Zanshin and added my todo.ics
--- for some reason, none of the todos seem to have showed up – and there’s _a lot_ of them ---
7) While the things were syncing, I started moving some folders from /home/backup_hook to /home/hook – documents, etc., (no settings).
--- at this point my laptop froze and after 15' I hard-rebooted it ---
8) When I logged into Plasma again, I got greeted by Zanshin not working and Akonadi claiming it’s not registered at D-Bus and agents are missing
9) just as I was writing point 8) the Akonadi Migrator popped up and things started working again. Oddly enough I can see my todo.ics twice in Zanshin and twice in Akonadi Console – as “Todo” and as “akonadi_agent_ical_2” (or something like that)
10) Once the Akonadi Migrator was done, I restarted the Akonadi server.
--- now it does *not* work again ---
--- but I have mysqld hammering my CPU ---
At point 8) this is the report I got: https://thatfunkyplace.wheremymonkeyis.at/s/QeFFTWxBm6AoJpL
(for a later report, I’m still waiting for the button in Akonadi Console or Zanshin to actually pop up something)
--- now MySQL stopped churning and Akonadi works again ---
11) KMail seems to work OK, but both Korganizer and Zanshin show empty – no entries, even no resources listed at all. Which is doubly-odd because the resources are clearly listed in their respective settings dialogues as well as in Akonadi Console.
--- …and MySQL is churning 100% CPU again. ---
12) After MySQL stopped eating all the CPU, I can see some resources and entries in KOrganizer and Zanshin again – oddly enough, the todo.ics _again_ shows twice: as ”TODO” and as “akonadi_ical_resource_2”
--- next day ---
Hm, I don’t like this one bit …I just noticed that after all that MySQL churning, the vast majority of the messages in KMail show as empty. Especially anything older than 8 months.
…what I like _even less_ is that this seems to have now replicated to the server-side as well. so even in RoundCube I see those messages empty. This is pretty bad.