[mythtv-users] High mysql cpu usage

[Henk D. Schoneveld]

On Jan 11, 2013, at 8:14 PM, Paul Raison <paul at raison.org.uk> wrote:

> 
> On 11 Jan 2013, at 15:13, "Michael T. Dean" <mtdean at thirdcontact.com> wrote:
> 
>> On 01/11/2013 12:18 AM, Juhani Rautiainen wrote:
>>> On Thu, Jan 10, 2013 at 10:47 PM, Jarle Thorsen<jarlethorsen at gmail.com>wrote:
>>> 
>>>> To sum up the information in this thread so far:
>>>> 
>>>> Several people report the same problem with high CPU usage for mysql (and
>>>> unusable system) while the EIT rescheduling is runnnig.
>>>> 
>>>> None of us have seen any real improvement by removing barriers from our
>>>> filesystem and we all have capable hardware.
>>>> 
>>>> Maybe it is just the fact that we have 100+ channels with EIT turned on
>>>> that makes us affected by this "bug"? Maybe somebody with more mysql skills
>>>> than me could have a look at the mysql-fu to see if the EIT rescheduling is
>>>> as optimized as it can be?
>>>> 
> 
> I previously had problem with mysql running at 100% cpu and the mythfrontend becoming unresponsive for 50-60secs. I resolved the issue by changing a couple of tables (think namely program & recordmatch) from MyISAM to InnoDB storage engines. Been no problems now for quite a while. For me the issue started with 0.25 release.
another suggestion, maybe totally wrong, if you're watching top for CPU usage, what does IO% say at that same time. If it's almost 100% you could use iotop -o to see what/which operation is causing this. In another situation I also observed a non-responsive system which was caused by kswapd doing weird things. I downgraded my kernel to 2.6.33 to get rid of it.

Henk
>  
> Regards
> 
> Paul Raison
> 
> 
> 
> 
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