[kdepim-users] Work-around to issues with Akonadi file based caching (was: Re: rant)

[Martin Steigerwald]

Hakan,

Am Sonntag, 15. Februar 2015, 17:19:45 schrieb E. Hakan Duran:
> On Friday, February 13, 2015 10:34:28 AM Martin Steigerwald wrote:
> > ...
> > The SizeThreshold thing helped me with that. But have caution: This is
> > no official recommendation of Akonadi developers. Still, it gave me a
> > good improvement with performance and latency *and* seemed to have
> > solved the insane amount of file and data in file_db_data issue for
> > me. Or at least it worked around it successfully.
> >
> >...
> 
> Thank you once again Martin. I made the changes you recommended. I think
> it feels a little more responsive now, but I have to use it a few more
> days to make a more objective call.
> 
> I still notice a growing file_db_data folder, proportional to the time
> akonadi is left on. I am considering to delete everything and start
> from scratch but I have so many accounts (e-mail, personal and work
> calendars, etc.) it feels like a waste of my time at the moment.
> Instead, I will keep turning akonadi off as soon as I check and reply
> to my emails, and then run fsck afterwards to get rid of the mess it
> generated until I have more time for the revamp or I am truly pissed
> :).

so far this change works for me.

Several POP3 accounts, one very large, all in one maildir, and a 30-day 
limited IMAP account:

martin at merkaba:~/.local/share/akonadi> find file_db_data | wc -l
32

martin at merkaba:~/.local/share/akonadi#1> du -sh file_db_data      
4,3M    file_db_data

Very large IMAP account from work:

ms at merkaba:~/.local/share/akonadi> find file_db_data | wc -l
2376
ms at merkaba:~/.local/share/akonadi> du -sh file_db_data 
663M    file_db_data


Hmmm, yikes. Its large in there, but at least not very many files. And 
well, it seems that are mails with larger attachment that Akonadi caches 
there:

ms at merkaba:~/.local/share/akonadi> du -sh file_db_data/* | sort -rh | head
11M     file_db_data/4735240_r1
11M     file_db_data/4735240_r0
11M     file_db_data/4735239_r1
11M     file_db_data/4735239_r0
9,4M    file_db_data/4734016_r1
9,4M    file_db_data/4734016_r0
9,3M    file_db_data/4731257_r0
8,6M    file_db_data/4731853_r1
8,6M    file_db_data/4731853_r0
7,2M    file_db_data/4732214_r1

And as I think I set the account to offline caching that even makes sense.


Well all it comes down to is: If you have lots of mails that are larger 
than 32 KiB the change won´t help. You may try with an even larger 
SizeThreshhold, but as I did never test it and no of no one else who did, 
I can´t say whether it would work. Also I don´t know the maximum limit for 
SizeThreshold, I don´t know the limit of MySQL for storing these blobs in 
the database.

All I see here is that SizeThreshold=32768 works okay here.


These figures are weeks after the change and I didn´t do any manual 
optimization aka akonadictl fsck or akonadictl vacuum. I may try it on the 
work account next week to see whether Akonadi again lost track of some 
files.

Ciao,
-- 
Martin 'Helios' Steigerwald - http://www.Lichtvoll.de
GPG: 03B0 0D6C 0040 0710 4AFA  B82F 991B EAAC A599 84C7
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