[mythtv-users] Frontend started crashing after migrating DB from Mythbuntu 10.04 to MB12.04

[Stephen Worthington]

On Sat, 15 Mar 2014 11:02:13 -0500, you wrote:

>I'm starting (finally) to migrate from stable 10.04 system to 12.04 in
>preparation for jumping on 14.04 when it comes out.  I got the MB12.04
>system installed on a separate HD in the same system (swapping drives
>between power cycles), and everything was working, including mythfrontend
>startup.  Then I dropped the empty database and reloaded it with a copy of
>the database from the MB10.04 system.  It looked like it upgraded ok, but I
>can't get mythfrontend to open up.  It blanks the screen on startup, but
>after something like a minute it just quits.  I haven't been able to figure
>out what is happening and barring suggestions from the mailing list, I'm
>about ready to wipe the HD and start over with the MB12.04 install, taking
>advantage of my notes for the steps I took to get this far the first time.
>Here are pastebin links to the logs for the back and front ends:
>
>mythfrontend.log <http://paste.ubuntu.com/7090687/>
>mythbackend.log <http://paste.ubuntu.com/7090685/>
>
>Any help would be greatly appreciated.

The mythmusic plugin needs to update its part of the database the
first time mythfrontend is run after a database upgrade.  That is what
is happening.  The first part of the upgrade process is to backup the
existing database, which takes quite a while.  While the backup is
being done, mythfrontend does not seem to be doing anything and its
screen is blank.  Depending on how large your database is (it is
roughly proportional to the number and size of the recordings you have
stored), the database backup can take many minutes.  The last message
in the frontend log you posted is saying that backup has been
completed.

It is quite a while since I did a database upgrade like that, so I am
not completely sure of the sequence of things, but I think that after
the backup completes, a question appears on screen asking if you want
to go ahead with the upgrading of the music database.  It is possible
that you are not waiting long enough for that message to appear, or
that for some reason it is not actually visible but mythfrontend is
still waiting for you to answer it.

When upgrading a database, the recommended procedure is not to run
mythfrontend first, but to run mythtv-setup, and let it trigger the
main database upgrade, before running mythfrontend and getting it to
do the music database upgrade.  When I upgraded to 12.04, I ran into
the sort of problems you are seeing until I followed that procedure.
See here:

  http://www.mythtv.org/wiki/Backend_migration

The music database is only accessed by mythfrontend, so mythbackend
does not touch that part of the database and leaves it to mythfrontend
to upgrade it as necessary, which is why it is not automatically
upgraded when the main part of the database is.

I would suggest that you try restoring the 10.04 database again and
running mythtv-setup first, then mythfrontend again, and this time run
tail -f on mythfrontend.log so that you can see when the backup is
complete.  When it is complete, look for the upgrade message.  If you
do not see it then, you may be having theme problems and it is not
actually visible, so try answering the question blind anyway.  Try
hitting Y and <Enter>, or yes and <Enter> or maybe just <Enter>, to
tell mythfrontend to go ahead with the upgrade.  If you manage to
answer the question correctly, you should see messages appearing in
mythfrontend.log telling you the database upgrade is happening.  If
you give the wrong answer, I think mythfrontend exits, and when run
again will again backup the entire database before trying the music
database upgrade again.

If that still does not work, what I found when I had the problem was
that if I uninstalled the mythmusic plugin package, then mythfrontend
would start up normally.  The mythmusic package can be reinstalled
later once mythfrontend is working and any theme problems have been
sorted out.