[Kde-pim] Akonadi MySQL backend: tuning for larger accounts or switching to MariaDB with a different storage engine?

[Martin Steigerwald]

Am Mittwoch, 26. März 2014, 20:22:28 schrieb Martin Steigerwald:
> > > InnoDB is difficult as innodb_buffer_pool_size needs to take free memory
> > > into account which can change quite rapidly on desktops or anything else
> > > than a dedicated database server. A engine which uses Linux pagecache
> > > for
> > > most of its caching would be interesting I think.
> >
> > 
> >
> > Maybe we could have some kind of "initial setup" tool that would check
> > available memory and would update innodb_buffer_pool_size depending on
> > that
> > (taking in account some max limit, min limit, max percentage, ...)
> 
> Well I am backing off a bit at the moment. Maybe those read bursts I
> observed  where not related to InnoDB buffer pool size, but to something
> else. If I see it again, I try to look in Akonadiconsole as to what Akonadi
> is doing there.

There is indeed some stuff in Akonadiconsole there.

And now I had this long wait for KMail to do anything again. After downloading 
/ filtering new mail.

According to Akonadiconsole akonadi nepomuk feeder was indexing and according 
to atop akonadi maildir resource was hogging one Sandybridge core for 100% for 
minutes.

Akonadiconsole Query Debugger showed queries to get payload bodies, also from 
that kernel-ml folder. And I have quite some wait times in Job Tracker now, 
for Akonadi::ItemFetchJob. I have wait times up to:

00:05:33.069

Five of those wait times between 5 and 6 minutes.

Four between 2-3 minutes.

Five between 10-20 seconds.

Why this time is so long, I don´t know.


Akonadi seems to block out KMail due to this mail indexing background 
activity, which I reported already:

Bug 331848 - displaying, moving, deleting mails takes 10-20 seconds when 
Akonadi synchronizes in background 

https://bugs.kde.org/show_bug.cgi?id=331848

But at work I do not have mail indexing enabled so far, yet this was on NFS 
still as I reported the bug.


I think I just disable mail indexing for now for this POP3 setup, until I can 
install KDE SC 4.13 including new KDEPIM and Baloo.

Well, I learned about debugging performance issues with Akonadi.


I am inclined to close my MySQL tuning related report. I do not have the 
impression anymore that it is very important at the moment. What do you think?

So finishing analysis for now.

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