[mythtv-users] Is there an approved may to remove frontend settings?

[R. G. Newbury]

On 02/02/14 07:18 AM, Anthony Giggins wrote:
> is there an approved way to remove old frontend hostnames from the database?
>
> I've got a mix of old hostnames with a mix of with & without domain names.
>
> Happy if someone could point me at the correct tables I have a good
> understand of SQL.

"Approved"? No. Like any deep spelunking, it can get dangerous.
So start with a backup of the database, or 2 or 3!

The settings table holds settings for each 'instance' of myth. It sounds 
like you may have entries which actually point to the same box, due to 
your namechanges. And some entries are properly set to NULL. A complete 
mythtv setup puts about 250 settings into the settings table.

As a first step, make sure that your computer has the correct hostname 
set in /etc/hostname (and that 'hostname' on the command line returns 
the same thing!).

Then look at the settings table.
mysql> select * from settings;
and
mysql> select * from settings [where hostname="correcthostname"];

If you get 750 records and 300 records respectively, you have some work 
to do!

You may have active entries under the hostname 'localhost' too. So you 
cannot just delete ALL the 'incorrect' settings without checking that 
there is a correct duplicate value entry. Most of the 'localhost' 
entries can be/should be set to your hostname. But don't mess with the 
'NULL' entries.

You can use:
select value, data, count( value) from settings group by value having 
count(value) > 1 ;
to find duplicate instances of 'value' in settings
Similar calls will give duplicates in other tables.

Beyond that, the hostname is also a field in the following tables:
  capturecard
  displayprofilegroups
  housekeeping
  inuseprograms
  jobqueuea
  jumppoints
  keybindings
  livestream
  music_playlists
  profilegroups
  recordedartwork
  recordedfile
  recorded
  scannerpath
  storagegroup
  tvchain
  weatherscreens
  weathersourcesettings

Having duplicate hostname rows in most of these tables is innocuous as 
only the 'correct' entries will be in use. You can easily do a 'delete 
from ... where hostname="wrong";' in those tables.

But you will have to check to see if items with the 'wrong' hostname' in 
the recorded* tables are actually visible in 'Watch Recordings'. You may 
hange those entries, and find that you have more recorded shows than you 
thought!

You *may* want to do backups at intermediate stages and proceed carefully.


-- 
              R. Geoffrey Newbury