[mythtv-users] REPAIR/OPTIMIZE in HouseKeeper (was Re: Running optimize_mythdb.pl before mythfilldatabase)

Michael T. Dean mtdean at thirdcontact.com
Fri Feb 23 07:55:01 UTC 2007


On 02/22/2007 10:25 PM, f-myth-users at media.mit.edu wrote:
>     > /me wonders if you would still have the "trashed recordings" issue with 
>     > a more current version of Myth (like 0.20-fixes or even 0.19-fixes)...
>
> Yes.  Many others have reported exactly the same problems in .19, .20,
> and SVN, which is why Chris has been looking into it.  The problem is
> that the scheduler runs when a recording ends, its queries hold a lock
> on the entire recordedmarkup/recordedseek table, and that hangs the
> process that's emptying video buffers; see all the prior discussion
> from a few weeks ago.

I remember it.  I read it closely--and with interest--because I've never 
seen any of those issues.

>     > Only wondering because I don't have these issues with 4x pcHDTV 
>     > HD-3000's (often all four are recording simultaneously), 
>
> You're not understanding something here.  It's not an I/O load issue.
>
> Do HD3000's not write data into recordedmarkup/recordedseek?

Yep.  MPEG-2, just like with IvyTV, so it needs a seektable.

>   Are you using innoDB?
Nope.  MyISAM.
>  Do you have particularly simple scheduling rules with
> very few "all channels" situations?

72 recording rules, including 1 power search (new series), 4 Fine One 
(for movies), and 67 Any Channel/All episodes rules.  Oh, and I just 
cleaned out about 10 Any/All rules last week.

>   And---very important in the other
> direction---do you record 100% of all your recordings with hard
> padding appended to their ends?  [After all, if you rarely postroll,
> that means that one show ends -just- as one begins, which puts the
> scheduler query right at the start of the new recording, where it's
> likely that any corruption will be overlooked 'cause it's not actually
> part of the program you're watching, or is perhaps written off as "the
> tuner is weird for the first few seconds and writes bad data", or
> whatever---except in the common case of a program that ends on the
> half-hour in the middle of another that goes the full hour, etc.  But
> if you typically postroll -and- typically have a recording still in
> progress on another tuner when that postroll ends, that puts the
> scheduler query smack in the middle of something you're trying to
> watch, where it's really obvious.  Yet not doing pre/postrolls
> guarantees (in my situation) simply losing beginnings and endings of
> recordings, so that's no solution, either, and wouldn't help the
> half-hour/full-hour program case, either.]
>   

No hard padding, but I probably have 1 show per night ending at :01 
after while others are recording.  Also, when mfdb finishes, it requests 
a complete reschedule, and I know that happens relatively frequently 
while I'm recording on multiple cards.

> Also note that it's not just "end of recording"---deletions also cause
> scheduler runs and also glitch my recordings.  I'm having to be
> careful never to delete anything while a tuner is in operation,
> unless I feel like waiting until only -one- tuner is running and
> doing the deletion during a commercial.  This is hardly what a "PVR"
> is all about... :)
>   

Oh, and I watch and delete, and most of my watching time is during 
primetime, which is also when I record about 90% of my shows, so I do a 
lot of deletes during recording.  (I am using slow deletes, but that 
shouldn't have any effect on it.)

But, unfortunately, I can't help to diagnose the problem (which is why I 
didn't participate in the discussion)--because I'm not seeing it and I 
don't know why not.  So, really, you can just ignore my wondering.

Mike


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