[mythtv-users] mythfilldatabase stunning my system

Mike Perkins mikep at randomtraveller.org.uk
Wed Jan 24 17:31:42 UTC 2007

Greg Foster wrote:
> On 1/18/07, M. Scott Doerrie <mdoerri at cs.jhu.edu> wrote:
>> I have recently had a similar problem with mythfilldatabase and thought
>> I'd share my solution here.  We have a large channel lineup of over 500
>> channels -- not that we get all of them, but we like to see them in the
>> program guide because we can order them as desired.  Though
>> mythfilldatabase may be niced, it is not all that computationally
>> expensive.  Rather, the updates are IO intensive, and MySQL attempts
>> them as fast as possible.  This interferes with recording and playback,
>> causing all manner of visual artifacts.  Sometimes the backend simply
>> stops streaming or, less frequently, exits.  I thought that increasing
>> the mythbackend ringbuffer would be futile since the updates take well
>> over an hour.
>> Since the operations are IO bound, I have installed a 4G drive for the
>> MySQL database.  The hope was that this would reduce load on the primary
>> drive, allowing the backend to continue streaming.  Since it is an older
>> drive and can not communicate at the same bus speed as the primary
>> drive, I placed it on the secondary ATA bus.  (This bus also contains
>> the DVD-RW, but I doubt I'll be watching DVDs at 5 am when I update).
>> This solution seems to be working fine.  The frontend will rarely have a
>> playback artifact, but they are not present in the recordings.
> [snip]
> Scott,
> Any luck with your changes ?  Seeing the same issues here with a large
> lineup, to the point where mythweb doesn't come back with the tv
> listings before things time out or get ugly.
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Possible tangential solution, maybe - move your MySQL database to a 
different box? Doesn't have to be in the same box as your busy backends.


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