[mythtv-users] Threaded File Writer 'taking a long time'

[John Pilkington]

On 19/10/12 17:53, Craig Treleaven wrote:
> At 4:28 PM +0100 10/19/12, John Pilkington wrote:
>> Over the past few days I've been seeing this quite often.  I don't
>> remember seeing it before.  I first noticed it after an upgrade on
>> Wednesday to mysql 5.5.28-1 on Fedora 16 x86_64, but I can't swear
>> that it hadn't been happening before.  Recordings seem ok but I've
>> seen instances of over 6 seconds.
>>
>>
>> 2012-10-19 13:54:18.836330 W
>> TFW(/mnt/sam1/recb/1703_20121019125800.mpg:78): write(55648) cnt 18
>> total 1017644 -- took a long time, 6044 ms
>> 2012-10-19 13:54:24.314063 W
>> TFW(/mnt/sam1/recb/1703_20121019125800.mpg:78): write(56212) cnt 35
>> total 1977948 -- took a long time, 5477 ms
>> 2012-10-19 13:54:26.330029 W
>> TFW(/mnt/sam1/recb/1703_20121019125800.mpg:78): write(56024) cnt 19
>> total 1074044 -- took a long time, 1058 ms
>>
>> The latest mysql changelog includes:
>>   - Export THR_KEY_mysys as a workaround for inadequate threading support
>>   Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=846602
>>
>> That report seems to be Fedora-specific.  Has anyone else seen this?
>
> Don't know about MySQL but, using 0.25.2, I was experiencing HDHR
> recordings that would fail.  Thread is on mythtv-dev:
>
> http://www.gossamer-threads.com/lists/mythtv/dev/530543
>
> Bottom line, applying the fix committed to 0.26 has solved the problem
> for me.  Previously, I would have at least one failed recording every
> 1-2 days.  Haven't had one in the last 5 days since applying the patch:
>
> http://code.mythtv.org/trac/changeset/dc0bf9b03248775bbd186f4029b217bba9d4b6a6/mythtv
>
>
> HTH,
>
> Craig

Thanks for the links.  I'm on v0.25.2-25-g0817eb2.  I've seen a couple 
of flurries of reports immediately after a previewgen, and there's been 
a fix lowering the priority of that, although I don't have it installed. 
  I'll look again at ionice-ing other disk-intensive stuff and wait a 
bit longer before doing anything else; if problems continue I might try 
reverting mysql, too.  I'd prefer not to build from source if I can 
avoid it.

Cheers,

John P