[Pdns-dev] virtual memory issue and gmysql

[Stephen Manchester]

Oh, and I'm not saying this is a bug in pdns exactly.  Believe me,  
I've found more than enough "quirks" in the MySql client libraries to  
drive any person insane.  :p

Just haven't had a chance to figure out where the actual problem is yet.

On Oct 2, 2007, at 10:06 PM, Stephen Manchester wrote:

> This would correlate with what I've seen as well.  We are not that  
> busy at all, and even though I have our MySQL connection timeout  
> set for 8 hours, I'm sure a single connection could easily not get  
> used for that long of a time.  Not sure if pdns cycles the  
> connections regularly, or just uses the first available one, but if  
> the later, then that could explain it easily.  Still haven't looked  
> at the code.
>
> Just thought I'd drop the note.
>
>
> On Oct 2, 2007, at 9:47 PM, Patrick Domack wrote:
>
>> I did more testing, and actually watched the log file this time  
>> and the log shows this for every extra 10megs of memory allocated:
>>
>> Oct  3 00:31:08 blade2 pdns[13541]: Backend error: Failed to  
>> execute mysql_query, perhaps connection died? Err=1: MySQL server  
>> has gone away
>> Oct  3 00:31:08 blade2 pdns[13541]: gmysql Connection succesful
>> Oct  3 00:31:08 blade2 pdns[13541]: gmysql Connection succesful
>> Oct  3 00:31:13 blade2 pdns[13541]: Backend error: Failed to  
>> execute mysql_query, perhaps connection died? Err=1: MySQL server  
>> has gone away
>> Oct  3 00:31:18 blade2 pdns[13541]: gmysql Connection succesful
>> Oct  3 00:31:18 blade2 pdns[13541]: gmysql Connection succesful
>> Oct  3 00:33:18 blade2 pdns[13541]: Backend error: Failed to  
>> execute mysql_query, perhaps connection died? Err=1: MySQL server  
>> has gone away
>> Oct  3 00:33:18 blade2 pdns[13541]: gmysql Connection succesful
>> Oct  3 00:33:18 blade2 pdns[13541]: gmysql Connection succesful
>>
>> This is with a request rate of one every 29 seconds, and a mysql  
>> timeout of 60 seconds.
>>
>> This isn't an issue with busy servers, cause it never has a 60sec  
>> idle time between requests. I don't have this issue with 7 of my  
>> production server, just the 3 I setup and are in development  
>> testing, cause they aren't high load yet.
>> But this means a high load server, that has a temp routing issue  
>> or other problem, will also start to notice this issue.
>>
>> Quoting bert hubert <bert.hubert at netherlabs.nl>:
>>
>>> On Mon, Oct 01, 2007 at 03:30:24AM -0400, Patrick Domack wrote:
>>>> I have seen reports of this in the users maillist.
>>>
>>> Indeed - but quite a number of very large installations do not see a
>>> problem. So it has to be something site specific.
>>>
>>>> the rpm package for pdns-static version 2.9.21
>>>> on redhat el5 x86_64
>>>
>>> Can you count if the chunks of 10240KB it loses correspond to  
>>> certain errors
>>> in the log perhaps?
>>>
>>> And does your patch fully resolve the issue?
>>>
>>> Thanks.
>>>
>>>
>>> --
>>> http://www.PowerDNS.com      Open source, database driven DNS  
>>> Software
>>> http://netherlabs.nl              Open and Closed source services
>>>
>>
>>
>>
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