[mythtv-users] After 7y5m running, time to start from scratch after update to .27?

[Michael T. Dean]

On 11/25/2013 03:08 PM, Matthias wrote:
> Am 25.11.2013 05:41, schrieb Michael T. Dean:
>> On 11/23/2013 10:16 AM, Nick Morrott wrote:
>>> On 22 November 2013 21:16, Matthias Thyroff wrote:
>>>
>>>> Is my mythconverg overloaded? It is 2.0GiB in size. It resides on an
>>>> SSD.
>>>> The channel table is maybe a bit big, 3280 items. Definitely too big
>>>> for my
>>>> use case, many channels are duplicatedand I am not sure, why, I am only
>>>> using less than 100 in my frontends. For example, I have 28
>>>> duplicates of
>>>> the channel RTL from source 3, all of them get their channel data
>>>> from one
>>>> xmltv run in the early morning (I still start mythfilldatabase from
>>>> a cron
>>>> script; I never straightened out the method of running it via
>>>> housekeeping
>>>> which was, I think, introduced with 0.25. I also still start
>>>> optimize_mythdb.pl every time after the mythfilldatabase run).
>>> You really need to sort out your video sources and channels
>>> configuration - this doesn't mean throwing away your entire database.
>> Exactly.
>>
>> If channel/video source/input connections configuration is your
>> problem, you can "start from scratch" by simply going into
>> mythtv-setup's Video Source section and choosing "Delete all video
>> sources", then re-create your Video Source(s), re-connect inputs, and
>> re-scan/-fetch channels.  There is absolutely no difference between
>> doing this and starting with a completely blank database--except for
>> your not having to re-configure everything else in MythTV.
>>
>> See http://www.gossamer-threads.com/lists/mythtv/users/264034#264034
> Hello Mike,
>
> thanks for your reply!
>
> I am not sure: I think it might be different when you use data direct
> and scan the american networks... but using xmltv (tv_grab_eu_epgdata),
> scanning the astra satellite network and putting everything in a useable
> state is the single most time consuming task in setting up a myth
> system, to my experience. It gets worse when you also want to add some
> dvb-t receiver or maybe a dvb-c card, all delivering different subsets
> of the useful channels from astra. (In my current configuration, I am
> not doing that).

I'll agree that setting up channels is the worst part of configuring a 
MythTV box.  However, if you start with a new database, you'll have to 
do that, anyway.  So, rather than going full nuclear and throwing away 
your entire database just because you think you have a problem with your 
channel configuration, I'm simply suggesting you throw away *only* the 
channel configuration information with "Delete all video sources" as it 
will accomplish the exact same thing as starting with a new database and 
prevents your having to reconfigure everything else.

> It is also very possible that there is something I never really
> understood on how this is supposed to work, but cleaning out the
> hundreds of useless channels from astra, putting the useful channels in
> a wanted order (manually adding channums in mythweb seems to be the most
> efficient way) and adding the xmltvids (also in mythwweb) is very
> cumbersome. In "Starting from scratch", that represents 90% of the work.
>
> I am still considering doing it, as last resort.
>
> What I did last saturday, was deleting the unused source (#2), leaving
> the used source (#3 - not having number one shows you that I am evading
> "starting from scratch" since some changing tuners between dvb-c, dvb-t,
> dvb-s and dvb-s2). I also deleted all unused channels and all duplicates
> (in phpmyAdmin) and since then, I did not have a "backend at 100% CPU"
> situation. That is solved.
>
> What is not solved is the comunication problem between frontends and the
> backend (where, sporadically, but then consistently every 10 seconds or
> so, I get a huge popup saying "mythcontext: Backend is online" when I am
> in the recordings screen or also when I watch a recording... see archive
> for a more detailed description:
> http://www.gossamer-threads.com/lists/mythtv/users/555885?search_string=mythcontext;#555885
> ) That problem went away for about 24 hours after cleaning up my
> channels, purging the program table, re-running mythfilldatabase
> (thereby reducing the mythconverg database from 2GB to<400MB), and is
> back now. I would bet that this problem is not due to the channels list.

Agreed.  As a matter of fact, I would bet that the problem is not due to 
any MythTV configuration at all (TTBOMK, we don't have any "communicate 
incorrectly with the master backend" setting ;).

> If I were you I would tell me, if there is doubt in the consistency of
> the database (considering that the tables have been modified manually so
> many times), start from scratch before complaining. So I am considering
> it, with sorrow. Because the problem has not started after putting my
> hands on the tables, it has started after upgrading to .27.

And, yes, manual edits/modifications to the database may well be a good 
reason to start a "new" database, but I'd recommend throwing away only 
a) schema and b) re-creatable information.  In other words, I'd 
recommend you:

1) create a full database backup using: 
http://www.mythtv.org/wiki/Database_Backup_and_Restore
2) do a partial restore of a backup: 
http://www.mythtv.org/wiki/Database_Backup_and_Restore#Partial_restore_of_a_backup

This is the recommended approach for users who have corrupt or 
untrustworthy schemas or data.

> I am not there yet. But hey, it is autumn, raining outside, and cold...
> good time to invest some hours in myth, I suppose, it has always been
> worth it.

That is one good thing about MythTV--it can keep you busy when you're 
bored.  :)

Good luck,
Mike