[Pdns-users] Increased CPU usage after upgrade to MariaDB 10.6.11

[William Edwards]

Hi Winfried,

abang at t-ipnet.net schreef op 2022-11-26 23:51:
> Hi,
> 
> We recently had a similar problem when we updated from 10.5.12 to
> 10.6.10.
> 
> The cause was that the default behavior changed from
> 
> innodb_flush_method = fsync
> 
> to
> 
> innodb_flush_method = O_DIREC

I've used O_DIRECT even before the upgrade to MariaDB 10.6.11.

> 
> Which means, no kernel file caching.
> 
> If you have a too small
> 
> innodb_buffer_pool_size
> 
> in this case, there is a lot of disk I/O and thus a lot of CPU wait
> time.
> 
> Setting
> 
> innodb_buffer_pool_size = 8G
> 
> helped in our case.

I use the the default innodb_buffer_pool_size of 128 MiB, and have only 
a fraction of that in use.

> 
> Winfried

Thanks for your reply!

> 
> Am 26. November 2022 14:45:26 MEZ schrieb William Edwards via
> Pdns-users <pdns-users at mailman.powerdns.com>:
> 
>> Hi,
>> 
>> Are people on this mailing list seeing increased CPU usage when
>> using MariaDB 10.6.11 with PowerDNS 4.5.4?
>> 
>> Context:
>> 
>> I use PowerDNS with the gmysql backend. Last Wednesday, I upgraded
>> MariaDB 10.6.10 to 10.6.11 on 8 machines running PowerDNS. Since
>> then, MySQL's average CPU usage has increased from 2,5% to 55%. This
>> happens on all upgraded machines. However, this issue does not occur
>> on machines running MariaDB 10.6.11 without PowerDNS. PowerDNS
>> itself was not upgraded.
>> 
>> I am aware that this issue is (most likely) not caused by PowerDNS.
>> I am therefore only wondering whether others have seen the same
>> behaviour. If so, that would save me some debugging time.
>> 
>> Thank you,
>> 
>> William Edwards
>> -------------------------
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-- 
With kind regards,

William Edwards