[mythtv-users] How to setup MySQL connection for Mythbackend?

[Bjoern Voigt]

Since some years MythTV runs successfully on my main PC.

But because of a problem I decided to delete all MythTV packages from my
openSUSE Tumbleweed system and reinstalled the packages.

The problem is now, that Mythbackend does not find it's database
settings for the existing MySQL database anymore:

    # mythbackend --user mythbackend
    2017-07-03 23:53:08.459084 N  Using runtime prefix = /usr
    2017-07-03 23:53:08.459092 N  Using configuration directory =
    /var/lib/mythtv/.mythtv
    2017-07-03 23:53:08.459203 I  Assumed character encoding: POSIX
    2017-07-03 23:53:08.459212 W  This application expects to be running
    a locale that specifies a UTF-8 codeset, and many features may
    behave improperly with your current language settings. Please set
    the LANG variable(s) in the environment in which this program is
    executed to include a UTF-8 codeset (such as 'en_US.UTF-8').
    2017-07-03 23:53:08.459493 E  DBHostName is not set in config.xml
    2017-07-03 23:53:08.459520 E  DBHostName is not set in config.xml
    2017-07-03 23:53:08.459558 N  Empty LocalHostName.
    2017-07-03 23:53:08.459575 I  Using localhost value of cecilia
    2017-07-03 23:53:08.468163 E  [DBManager0] Unable to connect to
    database!
    2017-07-03 23:53:08.468231 E  Driver error was [1/1045]:
    QMYSQL: Unable to connect
    Database error was:
    Access denied for user 'mythtv'@'localhost' (using password: YES)

    2017-07-03 23:53:08.468285 I  UPNP Search 2 secs
    2017-07-03 23:53:08.812580 I  UPNP Search 1 secs
    2017-07-03 23:53:09.174760 I  UPNP Search 1 secs

    No UPnP backends found

    Would you like to configure the database connection now? [no]
2017-07-03 23:53:10.585796 I  No UPnP backends found

I tried two setups, but none of them saved the MySQL settings:

 1. "mythbackend --user mythbackend" interactively asks for the database
    settings, but does not save the settings.
 2. mythtv-setup also asks the settings, but also does not save the settings

One of the reasons can be, that I have three MythTV user names:

  * mythbackend: The user of the MythTV backend
  * mythtv: I do not know, where this user is used
  * myusername: the desktop user, which starts the MythTV frontend

As which user I have to start mythtv-setup?
Where are the database settings for MythTV backend?

Greetings,
Björn