Newest update:
Since my distro (Gentoo) made a new kde version (4.6.5) available, I gave kmail/kontact another try.
It is almost usable, so a big progress now.
The filters are still a mess. Every time I get a new mail, a popup appeares and lets me solve a conflict.
The async kmail <-> akonadi <-> actual data source is annoying.
I have to sync the folders a few times until the change is actually shown.
A few seconds (or sometimes minutes, I even had 2 hours!) the data is modified on the server.
Just as an example: I have an imap account and wanted to delete some old
mails (about 100.000 of them). Kmail was done with that in a few minutes (with blocked gui). Akonadi kept printing 107403 +FLAGS (\Deleted) lines for about 2 hours and the mails went away slowly.
Kmail 1.X did the same job in one or two minutes.
No I did not move a copy to the Trash folder, I really deleted them.
Connection was almost idle.

I'm still unable to enter pop3 passwords and akonsadi/kmail needs kwallet for imap.
Both are showstoppers so I reverted back again.
Maybe kde 4.7 gets better?

By the way, what are the seetings for you can make in the system settings -> Dekstop Search -> Desktop Query -> Customize index folders and Advanced Settings Memory Usage for?
I set it to not index anything at all and set memory to minumum 50MiB and
virtuoso-t uses over 800MB of RAM and Nepomuk needs 40GB of storage?

Can I get rid of both?

Honestly, KDE 3.5 had less features but it worked. What went wrong on the kde 4.X branch? With each 4.6 release things get worse. If that continues I don't know how long I will stay at kde. Would be sad to leave after almost 10 years of daily use.

Well in my case I've had enough and just got rid of KDE and installed Ubuntu for a change. I spent enough time trying to workaround KDE's rough corners and this KDEPIM 4.6 update blew it for me. I can't afford to spend hours making things work, trying this and that.
I'm not fond of Gnome, but this time I've had it.

KDE really need to focus on making their stuff work before going for bling-bling new features.

@fmjrey I have to agree with you. I'm using arch, too and since the update to kde 4.6.5 and kmail 2 the whole kdepim stuff is unusable. I deinstalled now the whole kmail and kontact stuff and use sylpheed instead - that's all I need, I have never used kmail for anything more which isn't achievable with sylpheed, too.

I really would like to uninstall this whole akonadi and nepomuk stuff and strigi and whatever it is called, but unfortunately that's not possible. I don't want a semantic desktop, I want a fast, classic desktop. I would really switch to gnome immediately but it's far too unflexible to me. xfce, lxde and so on would be ok, but I still need a lot of programs which depend on either kde or gnome (I'm thinking especially of a pdf-viewer with inverse search for latex and a graphical gpg tool) so I have to use one of these two and so I'm bound to kde.

I really like kde and it's flexibility, but they should leave the user more space to decide whether he really wants to use this "new stuff". E.g. if I disable akonadi I get a warning message everytime I start kde...

Well I think we'll see whether kde manages to get rid of the bugs or gnome 3 gets more customizable.
matse

I'm on arch too and have to agree with you. Kmail2 is really unusable, at least in my case. I would not expect such problems especially that release has been shifted many times as it was not stable enough. Unfortunately, it is still far from being stable.

This my experience with migration to new kmail2. I have about 8 POP3 accounts, 4.5G of old mails, that is about 25k mails. The automatic migration finished successfully in my case - at leas what I can see in log file.

Short version: I had to start from scratch, I can see mails in old structure but any operation takes ages, needs a lot of CPU power and makes my laptop battery empty in a very short time. So far I haven't found any possibility how to move old mails from kmail1 folder to new structure in ~/.local/share/.local-mail.directory folder.

Long version:
When kmail2 started after automatic migration I had my folders inside with no mails but it has been fixed by refreshing all. Then I could see all mails but unread. Marking them read didn't work - well it worked but after restarting kmail it was again unread. Meanwhile processes like akonadi-*, mysqld and virtuoso used all my CPU power. After some crashes of kmail, I have now 2x local folders and 1x kmail folders containing mails from old kmail structure. Both local folders contain only empty folder structure with inbox, sent mail, etc. CPU usage is still on the level that makes my PC unusable and it remains high even after exiting kmail.
So after this sad experience I have decided to start on clean user account and to try to find some working solution. I have created a new testing user, copied only ~/Mail folder containing all my emails from old Kmail1 and starting with Kmail2 from scratch. I have tried following:
1) Start kmail 2 -> local folders were created
2) Add new akonadi resource called somehow like "kmail directory" - I have understood that this resource has been specially created to support old kmail structures. After synchronization, new "Mail" folder with old mail structure has been added to kmail2.
3) Refresh all folders and subfolders and mark all mail as read. This action took a lot of time and CPU power.
4) A have tried to copy mails from old "Mail" resource to new "Local folders resource". It was possible to do it and after quite long time I was somehow able to copy everything from one resource to the other. So at the end both "Local folders" and "Mail" folder sowed the same structure, the same number of mails inside. I did the copy by drag&drop in kmail. So far so good, but the copy led to high CPU load caused by virtuoso-t, akonadi_mixedmailbox_resource and nepomuk.
5) My idea was that it is somehow synchronizing the stuff, also kmail showed something like synchronizing folder message. So I let it run during the night expecting that it would be fine in the morning. But it is NOT Whole night there was a high CPU load and in the morning Kmail still showed Synchronizing folder message. Size of ~/.local/share/.local-mail.directory folder was only 153MB.

I still want give a chance to kmail2 (mainly due to integration with KDE and look&feel - I do not like GTK apps) but at the moment I am not sure what to do. I do not want throw away all my old mails, I need to import them somehow. But I am afraid I will be forced to switch to some other application to be able to work with emails.

I have seen mention of the fact that it is a good idea to delete any old akonadi database before letting migration start. It would be useful if someone could confirm whether this made the difference between a poor/failed migration and a good one.

My experience of changing to kmail2 was not that bad actually, well, a little maybe.
I skipped the ressource migration wizard and completely redownloaded my mail it from the imap server. Maybe that saved me some trouble with high cpu and long loading times. On the other hand it didn't assign drafts/trash/sent folders to my accounts so I had to set this up manually (in account settings).

I have now upgraded to 4.7RC2 with my existing akonadi db which was actually running fine on 4.6. I then realized that on 4.7; akonadi had 200.000 files open. (lsof | grep akonadi | wc -l) . While this doesn't have any noticable effect on system performance I do get error messages from e.G. tail about too many files open and I don't think it's normal. Don't have the time/space now for an extensive backup and delete the akonadi db but will try later. Others who started fresh on 4.7 haven't reported this problem.

Okay people, I have in my KDE 3.5 760MB of emails in ~/.kde/share/apps/kmail/ and some not very complicated filters set. Already read this: http://userbase.kde.org/Kontact#Migrati ... new_distro

Should I finally migrate to KDE 4? Will I get very angry with CPU/RAM usage and disk writes akonadi does? Is it safe for my data? (yeah, done backup already). Any tips?

Another question, AFAIK I can still import my emails to thunderbird, will it be possible when they are in akonadi database? Is there anything related with akonadi's database to be considered? I can't afford non-working kmail after kde/mysql update. Using archlinux. Thank you.

I would say that it is not the right time to migrate with mail now. Kmail2 with akonadi stuff is not what I call stable and mature. If you do not really need to migrate I would suggest to wait another 6 months or if you want or are forced to migrate then I would go to KDE4.6.x without kmail2.

I maybe have some stable setup of Kmail2 now but I have to verify it very carefully first.

KMail2 is an early-adopters' release, not a stable one. As far as I know only Arch and Gentoo have it in their main repos. If you go for the update wholesale, you should bear that in mind.

Having said that, Akonadi only deals with metadata. It does not move your mail from its current position, so if you can read it in Thunderbird now you should have no problem reading it in Thunderbird after the migration.

If it is not stable it should't have the same tag/version/whatever of the stable KDE. I still don't understand why it has been released as part of KDE 4.6.2 if it is an "alpha" release

Maybe it's general KDE release policy since the 4.0 alpha release?

For me it is a complete mystery how this have slipped in a revision release. As far as I know KDE monthly revision were meant to introduce merely bugfixes and translation changes not such a massive changes in functionality (and with that a load of bugs).

For users (and distributions) it would be a lot more planning reliability if they knew that revisions contain only minor changes that usually won't produce problems. In contrast this revision was a complete mess.

You are complaining to the wrong people. This was a distro decision, not a KDE one. Complain to Arch if you think they were wrong to make that decision.

Horus wrote:Maybe it's general KDE release policy since the 4.0 alpha release?

For me it is a complete mystery how this have slipped in a revision release. As far as I know KDE monthly revision were meant to introduce merely bugfixes and translation changes not such a massive changes in functionality (and with that a load of bugs).

For users (and distributions) it would be a lot more planning reliability if they knew that revisions contain only minor changes that usually won't produce problems. In contrast this revision was a complete mess.

Fortunatly not all the distributors are shipping the new KMail 2.

As Anne says, distributors and users can choose

I was just looking on the kmail site what actually the official stable release of kmail is (since arch normally just uses software that is released as a final version) but I didn't find anything. Can anybody tell me where I can find this information and does the kmail team have something like a changelog?
Thanks
matse

I wonder what was the first release of KDE-PIM that included kmail2? (in the KDE SC tarballs)