[mythtv-users] Deleted recordings in mythweb

[Michael T. Dean]

On 01/22/2016 04:41 PM, Yianni wrote:
>> I think some miscommunication, there is in Group Filter but there
>> isn't in Group View. So you can set Filter to show Deleted, but then
>> only Deleted!
>
> Yes, it's my fault, sorry, I've got the program in Greek and I'm translating "on the fly" which apparently doesn't fly...
> It's in the Change Group Filter  menu, the first entry when pressing M, anyway. I've changed to English language
> and now the group is called Deleted, with one entry. Mythweb, shows 246 entries, one up from before.

Can you delete the already-deleted recordings from MythWeb?  Do they 
actually disappear if you do?

What's happening is there's a race condition that can occur when 
deleting (especially large numbers of) recordings and shutting down 
mythbackend (uncleanly), that can result in some recordings getting into 
a limbo state where they're not fully deleted, but they were supposed to 
be, so MythTV ignores them thinking they will be gone soon, even though 
the deletion process was interrupted and nothing is working to delete 
them, anymore.  All of the recordings in this state are ones that you've 
previously deleted, so you can re-delete them without problems.

Technically, MythWeb's showing the recordings is a bug in MythWeb. 
However, since it does show them, if you can actually delete them from 
MythWeb, that's probably the best way to clean them up.

Anyone with a large number of these probably got them when they upgraded 
to the version of MythTV that enabled the delete queue (Deleted 
recording group) for everyone.  There was a bug for a couple of days in 
the initial implementation of the patch that resulted in all the 
recordings in the Deleted recording group being immediately removed upon 
upgrade and--most likely--this resulted in people and/or process 
monitors thinking MythTV was locked up, which probably resulted in a lot 
of processes getting killed and leaving these broken recordings.

And, FWIW, to the best of my knowledge, this race condition won't occur 
(or at least, the time period where it can occur is so much smaller that 
it will nearly never occur) for users who enable:

Delete files slowly
Some filesystems use a lot of resources when deleting large files. If 
enabled, this option makes MythTV delete files slowly on this backend to 
lessen the impact.

So, to prevent more zombie recordings, anyone can enable that in 
mythtv-setup's General settings--whether you need it or not. There's not 
really a down side to enabling it, unless your backend happens to use 
NFS or CIFS to access its MythTV storage (in which case, you probably 
don't want it enabled).

Mike