Still performance issues, this time: Shrinking a folder with archivemail

Hi.

This is with KDEPIM/Akonadi 19.08 on Debian Sid. I know its a bit 
outdated, so if that is really considerably faster and less resource 
hungry with the more recent version, I am happy to learn about that.


I did

[…]~/.local/share/local-mail/[…]/.Debian.directory> archivemail -D 
"2019-12-31" -o […]/Debian devel-changes-ml 

devel-changes-ml:
    archived 121966 of 132644 message(s) (964.5MB of 1053.7MB) in 238.4 
seconds

cause the folder with that mailing list became really, really slow.

I am using archivemail since I have completely given up doing this 
within KMail/Akonadi. Last time I tried it was so slow it would not 
finish within hours to come.

I got all 4 cores of a Sandybridge dual core CPU clogged with PostgreSQL 
processes + akonadi_indexing_agent since more than half an hour. Well 
plus one pxz process to recompress the archivemail archive as xz.

Also it writes truly insane amounts of data to the disk.

I also cannot do anything in KMail other than typing this mail since 
more than half an hour. It does now show any individual mail or any 
folder contents.

However I only *deleted* (!) about 120000 mails. The only thing Akonadi 
has to do is to *forget* about them, cause archivemail completed the 
task at hand in less than 5 minutes already.

I truly believe that such an action should not use this amount of 
resources.

I will let it sit like this, let's see how long it will be going to hog 
this machine.


I hope that someday Akonadi/KDEPIM will have a somewhat *sane* 
performance behavior for things like this.

Let's see whether it sends out this mail straight away, but I bet that 
it will do.

Best,
-- 
Martin