Broken Sync (was: Re: kmail sigh)

[Sandro Knauß]

Hey,

> As of KDEPIM and Akonadi 17.08 Akonadi is still not able to perform a
> background task like syncing a folder… or (re-)indexing it, without making
> KMail wait for user requests.

Well it can totally perform a sync. The only missing bit is a good error 
handling and finding there a good solution is hard. See for example:
I move one mail from one folder to another. This triggers different actions on 
Akonadi side:
1. make a temporally move in mysql db
2. users see the mail was moved
3. in background the move happens independently
  - upload the mail into the new folder
  - check if upload was successful (and only then)
  - delete the old mail

Easy isn't it? The problem begins what happens when one of this things do not 
end successfully:
Upload failed - move the mail back?
What if the upload was successful but the deletion failed?
Within older versions in Akonadi, Akonadi has no concept of move, so Akonadi 
only got the message create this mail in that folder and a second message: 
delete this mail from this folder. So that's why the move and popping up 
already moved messages ... As Akonadi has now the concept of moving this 
source of errors is fixed.

Unfortunately those things were not spotted within the design phase of 
Akonadi, so many things needed to be added bit by bit to not break older 
code...Becuase good old kmail 1 just do the move instantly - so the UI was 
freezing there too :D But I definitely say, we are moving into the right 
direction and to be honest a replacement of Akonadi will have many other 
sources of uncertainty and errors. So "just" a replacement of Akonadi doesn't 
necessary makes everything shiny and working - if it would be that easy we 
would be the first promoting to switch to a better piece of software.

> I think is it one of the main pain points for many KMail users. Anders,
> correct me if I am not getting it. If I click in KMail, I expect it to
> respond. Not in 10 seconds, not in half a minute, not in a minute… but now.

I nearly see this waiting time with offline IMAP and when I see it I can't 
spot it/reproduce it. If you have a setup where you can reproduce it, than we 
can try to fix that... This is one of the biggest issues for us is that if we 
can't reproduce it, it is so much harder to fix it.

hefee