[arch-general] Question about mariadb replacing mysql

[Paul Gideon Dann]

On Wednesday 27 Mar 2013 12:22:51 Mike Cloaked wrote:
> Thanks - my experience was that although I had ensured that the mysqld
> service was stopped at the time of installing mariadb, it was also the case
> that since there was no mention of KDE that I could see in the original
> announcement I simply left akonadi running whilst installing mariadb.  I
> have not personally had any obvious issues arising after the change, and
> only realised after the event that akonadi uses it even though "systemctl
> status mysqld" shows it is inactive. That was the reason for my original
> post in case some surprise related to Pim in KDE may later appear for KDE
> users despite the process of change being executed correctly according to
> the announcement. On other machines I manage I ensured that the mysqld
> service was stopped as well as executing aknodictl stop before installing
> mariadb.
> 
> Since the feedback seems to indicate that there is no onward problem
> relating to KDE and mariadb once installed, even if that install was done
> with KDE and akonadi running at the time, I guess this thread can be
> closed. I appreciate the replies.

If you're curious as to why Akonadi seems to be running mysqld without systemd 
knowing about it, it's because Akonadi is using an embedded mysql database 
(like sqlite, but slightly heavier-duty and with more advanced features).  
It's not a "normal" mysql instance, and won't accept normal mysql client 
connections, for instance.  I suspect that because Akonadi knows that nothing 
else can use the database, it takes care of any necessary upgrade migration 
automatically when it starts.

Paul