[mythtv-users] Thumbnails not generated for mythweb

Michael T. Dean mtdean at thirdcontact.com
Tue Sep 30 23:10:10 UTC 2008

On 09/30/2008 02:33 PM, kanetse wrote:
> On Mon, Sep 29, 2008 at 8:44 PM, kanetse wrote:
>> Okay, I've fixed my groups storage config.  Even though new recordings
>> were going into my mythtv/store folder, my 'Default' group was
>> mysteriously blank.  I've since corrected that, restarted mythbackend
>> and httpd.  Still no new thumbnails are being generated?
> Found the problem.  I guess it (mythweb?) won't generate thumbnails
> for recordings made on a different machine.

Actually, MythWeb doesn't generate thumbnails, it asks the backend
running on the named host to send them.  If there is no host by that
name running mythbackend or if the recording files aren't on that host,
you won't get thumbnails.

>   Since I was changing
> machines, I had changed the hostname of my master backend,

without following instructions at
http://mythtv.org/docs/mythtv-HOWTO-23.html#ss23.15 or--better--...

>  so only the
> recordings made on the new master backend had non-zero-byte thumbnails
> generated.
> For future reference, here is the SQL command I issued:
> UPDATE recorded
> SET hostname = 'newservername.domain.com'
> WHERE starttime < 'date-of-move'
> So in my case, my first recording was made on the new server on
> 2008-08-29, so all recordings prior to that had the old server name.
> Thus, my date-of-move was 2008-08-29 in my SQL query.
> Hope that helps anyone else.

using http://www.mythtv.org/wiki/index.php/Database_Backup_and_Restore ,
you can change the hostname (and it uses a procedure that will work
regardless of hostnames--using the 23.15 approach will fail with some
"common word" hostnames, like myth or video or tv or ...).  If I were
you, I'd do another backup of your current database (with the script, of
course ;) and run the restore script to change the hostname (see the
--help output).  There are many places besides recorded where the
hostname should be changed.

Since you didn't change the hostname in the proper sequence, it's quite
likely that all the existing settings for the new hostname will cause
key uniqueness constraint violations, meaning that you may need to clean
up your DB a bit before the change-hostname works.  This is why I'm
recommending a backup before you run the script.

If you don't do this, your DB may work reasonably well, but then again,
you may later find other issues that you'll eventually track down as
resulting from broken data due to the "partial" hostname change you
currently have.

Glad you got it working, though.


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