[mythtv] Why MythTV didn't handle the UK Freeview lineup change

[Stuart Auchterlonie]

Ed W wrote:
> John, can you please stop opening new threads and keep the threaded
> discussion correct - if you don't know what I mean then please use
> google and learn about mail threading
> 
>> Please stop saying 'for some reason'. A work around and suggested fix
>> has been offered. The specific problem that made scanning fail to work
>> is that for some reason in some cases the channel scanner reuses
>> cached data from the database. If you use mythfilldatabase to manually
>> sync up the database before the channel scan, channels are properly
>> deleted. So to prevent channels being resurrected, you need to sync
>> the database before a channel scan. This might not fix the underlying
>> problem, but it makes the rescan work, which is all I've been asking for.
> 
> I have a guess that this problem might be as follows (might)
> 
> 
> - When you delete the channel I believe that the delete from the
> channels table happens immediately (not checked the code, but this seems
> reasonable). - However, it *may* not clear down the program table which
> contains the "what's on" info? (not checked)

Yes the channel is immediately deleted from the channels table.
I'd have to check the code, but i don't think the data is immediately
deleted.

> - It's possible (but unlikely based on what I observe normally) that
> your deleted channel number is re-used when the channel is added back
> again and as a result the program information (what's on) is apparently
> immediately visible when in fact it's just the stale info that applied
> to the previous channel
> - At any later stage doing some kind of refresh of the guide data will
> correctly update the guide data (as you would expect)
> 
> So (possibly) your problem revolves around you prefering to see no guide
> data after deleting and re-adding a channel, versus seeing stale data
> when doing the same.  In all cases refreshing the guide data is the only
> way to refresh the guide data!
> 
> Does this seem plausible?
> 

yes

Stuart