[mythtv-users] after update frontend hangs burning 100% of CPU

[Joseph Fry]

>  [This might or might not be related to "update failed now fe crashes".]
>>
>> I updated a mythbuntu system from MythTV 0.25 to 0.26.  The Ubuntu is
>> 12.04 LTS.
>>
>> I've never done a MythTV update before, only a very few reinstalls.
>>
>> Procedure:
>>
>> 0) backup the myth database
>>
>
>  7) the backend seemed to hang.  After a few minutes I rebooted.
>>     Now I know that the backend wasn't hung, it was just changing the
>>     databse to the new schema.  After the reboot, it seemed to
>>     continue from where it left off.
>>
>
> If you ever have a "failure" (or stop/kill mythbackend) during a database
> schema upgrade, you should always restore the backup you made in step 0
> (one at the old schema version that has never had an upgrade attempted),
> then start over and let the upgrade occur without interruption.  If you
> don't, you may have corruption in either the data or the schema.  So, I
> would recommend restoring the backup and re-doing the database upgrade.
>
> Also, it's always recommended to run mythtv-setup first (with no other
> MythTV applications running) after doing an upgrade.  It will perform a
> database upgrade for you (and actually tells you its doing so--though it
> doesn't tell you anything more after it starts and just shows a blank
> screen while it's upgrading) and when the UI appears, you can then check to
> see if you need to change any of the new settings.
>
>
>  8) I started the frontend (normally I don't run it on this machine).
>>     It seemed to hang.  The display was completely blank.
>>
>>     The backend was actually doing a database backup (why is
>>     that the frontend's job?).
>>
>
> Frontend plugins do database updates for themselves--the backend has no
> idea what plugins you have, let alone how their database schemas work.
>
>
>      After finishing the backup, the frontend hung, with no display,
>>     using 100% of one CPU core.
>>
> ...
>
>  9) I repeated (8) a couple more times.  Results were the same, including
>>     doing yet another database backup each time (wasn't the previous
>>     one good enough?).
>>
>
> That means that something still hasn't finished doing a database update
> (the logs will tell you what).
>
> I'm guessing you're cutting off some major database update for some
> plugin.  So, you need to go back to the step 0 pre-upgrade database and
> start the upgrade process over.
>
>
>  Note: MythWeb seems to work from another machine.  New recordings are
>> happening.  So lots of this system is working.
>>
>
> Which means that the backend database upgrade completed successfully.  I'd
> still recommend that you go back to the pre-upgrade database and  start the
> DB upgrade process over.  Unfortunately, you'd need to take the new
> recordings (which you can find with http://www.mythtv.org/wiki/**
> Find_orphans.py <http://www.mythtv.org/wiki/Find_orphans.py> ) and put
> them in Video Library to make them available to watch with the
> properly-upgraded-from-an-**older-backup database.
>
>
I noticed when I upgraded my machine that there was an unresolved conflict
between mythtv-common 0.25 and 0.26.  I had to fire up aptitude and
manually remove 0.25 to get 0.26 to install;  The update utility wanted to
do a "partial upgrade", as you seem to describe in step 4?  I'm not sure
that's your problem as I would suspect larger issues if you were using an
older version of mythtv-common... but I would double check that you have
0.26 versions of all the packages all the same.  I upgraded another
frontend a day later, and this conflict seemed to have been resolved in the
repo's.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.mythtv.org/pipermail/mythtv-users/attachments/20130401/83f55bc2/attachment.html>