Bug 404538

Summary: akonadi fails with "multiple merge candidates" after failed IMAP sync
Product: [Frameworks and Libraries] Akonadi Reporter: Jens <jens-bugs.kde.org>
Component: serverAssignee: kdepim bugs <kdepim-bugs>
Status: RESOLVED DUPLICATE    
Severity: normal    
Priority: NOR    
Version: unspecified   
Target Milestone: ---   
Platform: Neon   
OS: Linux   
Latest Commit: Version Fixed In:
Sentry Crash Report:

Description Jens 2019-02-18 22:04:21 UTC 
Using KDE Neon with all updates applied, based on Ubuntu 18.04.

For the last few weeks, Kontact has not been updating its mails any more and I only see "retrieving folder contents ..." in the messages window.
I tracked this down to an Akonadi issue where - it seems - an IMAP remotely stored mail was deleted twice. Something in the mail database has gotten out of sync, and Akonadi is not clever enough to fix it.

I'm going back to Thunderbird for now. Despite KMail definitively being the better mail app.

Sorry, gals 'n' guys.
I went from Ubuntu to KDE Neon because I found KDE is by far the better desktop experience now that Unity is going (I liked Unity).
I tried Kontact/KDE and was surprised what features it had compared to my Thunderbird/Lightning/SOGO setup with Caldav and Carddav.

It worked great at first, maybe except for the weak HTML support in the mail editor (especially when replying).

Then KMail started stalling when fetching mail, mostly after resuming from sleep mode, or when cleaning up inboxes with a lot of moving and deleting email.
Some research pointed me to the Akonadi framework running in the background, and a ~2GB MySQL database in .local/share/akonadi acting as "cache" for all my mails.

And this "cache" kept breaking on me. "akonadictl restart" on the console spew thousands of "multiple merge candidates" and "lock time exceeded" errors, which appeared again and again regardless how often I deleted my whole KDE setup and configured everything from scratch.

Thunderbird is clunkier, not as nice, not as fast.
But it *works*.
I have never lost email. It can find the right email quickly with the global search feature and "drill down" options.
Whatever local database it has, it doesn't break on me and doesn't create duplicate or missing emails.
It uses about a third of the memory that Kontact + Akonadi + the mandatory MySQL server uses, and does not create *yet* another cache copy of my emails.

Please close this bug only after Akonadi has been made either significantly more robust or replaced by something more robust.

I will stay with KDE, and I will keep my Akonadi configuration, so if there are follow-up questions, I'm happy to answer and do some research to help fix this.
Comment 1 Christoph Feck 2019-03-08 19:48:50 UTC 
> Akonadi is not clever enough to fix it

Yes, it's very complex and not easy to debug. Developers that use Akonadi seem to never get those issues. But they need to reproduce those to be able to fix them.

> I found KDE is by far the better desktop

Some corrections: The desktop is called Plasma, the community is called KDE.

Additionally, the choice of the desktop does not limit the choice for the applications you use. There should be no problem to use applications not made by KDE. In fact, many Plasma users run Firefox, Thunderbird, or other GTK based applications.

> Please close this bug only after Akonadi has been made either significantly more robust

Sorry, but we do not keep duplicates open just because someone thinks it's their private ticket.

*** This bug has been marked as a duplicate of bug 399167 ***
Comment 2 Jens 2019-03-09 06:39:07 UTC 
>> Akonadi is not clever enough to fix it
> Yes, it's very complex and not easy to debug. Developers that use Akonadi seem to never get those issues. But they need to reproduce those to be able to fix them.

This is why I kept my database and logs and am waiting for a request from a developer to help in debugging.
I know it's hard to get an application into a "known broken state" for debugging.


> Additionally, the choice of the desktop does not limit the choice for the applications you use.

I know. I am using Thunderbird for now and it works fine.
But I liked the better integration into the rest of the desktop that Kontact/KMail/... offered.

>> Please close this bug only after Akonadi has been made either significantly more robust
> Sorry, but we do not keep duplicates open just because someone thinks it's their private ticket.

That's completely fine if there is a real duplicate.