[mythtv-users] mythfilldatabase stunning my system

[Chris Rouch]

On 11/26/06, Mike McKay <mike.mckay at dsl.pipex.com> wrote:
> I am running mythTV backend and frontend on an Athlon XP2000+ (processor
> clock 1.7 GHz) with 500 MB of memory and a Hauppage Nova-T, PCI, DVB-T
> tuner.
>
> When watching TV, the frontend, backend, mySQL and X take around 20% of
> the processor.
>
> When mythfilldatabase runs, however, it brings everything else to a
> halt.  The system becomes extremely unresponsive and cannot play TV, or
> anything else for that matter.  Mythfilldatabase seems to terminate
> normally after running for upwards of an hour and often in excess of two
> hours and during this time my system is unusable for anything else.
>
> On examination, I find that mythfilldatabase is taking 360MB of
> *resident* (not virtual) memory out of the 440MB available to users.
> Its processor utilisation is about 50% to 100% but I don't think this is
> a cause for concern because it has a "nice" value of +10 set.  I'm
> currently assuming that the resident memory usage is what's causing the
> problem.
>
> I've read the relevant documentation looking for a solution or a way to
> mitigate its behaviour but the only thing I've found so far is the
> parameter --days which I've set to 14.  This seems to have had little
> effect.  I use the UK's "Freeview" DVB-T service which provides 40 or so
> channels but from the listings in the mythTV programme guide,
> mythfilldatabase is downloading data for a large number of channel that
> I cannot receive.  Setting things so that these are not loaded might
> reduce the workload but I cannot see how to do this.
>
> These steps, however, are only ever going to reduce the size of the
> problem to some extent but are unlikely to remove it.  My understanding
> is that mythfilldatabase is downloading a quantity of text information,
> munging it to some extent and loading it into the database.  I cannot
> imagine how it comes to need 360MB of resident memory.  Is it really
> supposed to behave like this?  It's not as if it's doing anything that's
> computationally heavyweight for heavens sake !
>
> I'm considering adding more memory but the system has plenty of memory
> to handle everything else that I ask of it and I'm put off by the
> possibility that mythfilldatabase might just use all the additional
> memory as well.  I'm also reluctant to add memory to deal with such
> perverse behaviour.
>
> Can anyone suggest how to fix or alleviate this problem ?

It sounds like you need to train your grabber (tv_grab_??) to only
look for the channels you want. How to do that depends on the grabber.

You could also run mythfilldatabase from cron at a time you don't
expect to be doing anything else instead of having it run
automatically.

I'd also expect the duration to be roughly proportional to the number
of days, so try reducing from 14 to e.g. 3 days.

Regards,

Chris