[mythtv-users] MySQL server has gone away

Michael T. Dean mtdean at thirdcontact.com
Fri Nov 6 19:51:41 UTC 2009


On 11/06/2009 02:17 PM, Dan Wilga wrote:
> At 8:39 AM -0800 11/6/09, Yeechang Lee wrote:
>> Dan Wilga says:
>>>  IMHO, a value of 600 (10 minutes) should be plenty. And on a system
>>>  where you generally only have a few clients at most, that value
>>>  should not result in too many zombie connections.
>>
>> Just checked my my.cnf and it was set to 93600 (!); same with
>> interactive_timeout. Should I lower one, or both?
> Don't bother, unless you're using lots of applications which use MySQL 
> and don't disconnect properly--which is unlikely.
>
> These timeouts are there to keep clients that crash or otherwise fail 
> to close their connections from consuming MySQL's resources by keeping 
> the "slot" open. You'd probably have to make an application crash a 
> dozen times in a row during that period before you would even notice a 
> slight difference in speed.
>
> If you make this value too low, you can run into situations where the 
> client retrieves some data, takes a long time to process it, and then 
> tries to fetch the next bit of data but can't because its connection 
> has been dropped. 

For example, nuvexport can be affected by too-low timeouts.  If your 
system takes longer than 8hrs to transcode some show (which happens to 
some users--especially for long recordings), the MySQL-default of 8hrs 
will cause it to fail (/after/ at least 8hrs of processing, of course :).

Mike


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