maria-discuss team mailing list archive

[jocelyn fournier <jocelyn.fournier@xxxxxxxxx>]

It’s not that tiny, this article is a bit old, but still valid:

https://www.percona.com/blog/2008/11/21/how-to-calculate-a-good-innodb-log-file-size/

If you don’t need a big redo log, reduce its side to avoid slow crash recovery

> Le 27 juil. 2022 à 15:23, Gordan Bobic <gordan.bobic@xxxxxxxxx> a écrit :
> 
> 10.5+ only uses a single log file, so that is 1x1GB.
> And 1GB is tiny, IMO it should be a default these days.
> I would only even consider something smaller if I was running on an
> older Raspberry Pi or something similarly constrained.
> 
> 
> On Wed, Jul 27, 2022 at 4:11 PM jocelyn fournier
> <jocelyn.fournier@xxxxxxxxx> wrote:
>> 
>> Hi Cédric!
>> 
>> Just to be sure, do you really need the 2x 1G log_file_size ?
>> 
>> BR,
>>  Jocelyn Fournier
>> 
>>> Le 27 juil. 2022 à 14:36, Cédric Counotte <cedric.counotte@xxxxxxxxxx> a écrit :
>>> 
>>> Reading this: https://jira.mariadb.org/browse/MDEV-27295
>>> 
>>> It's quite unclear when it is fixed or reverted.
>>> 
>>> That said I read that the following setting might fix it:
>>>      SET GLOBAL innodb_max_dirty_pages_pct_lwm=0.001;
>>> 
>>> Is that correct and should I try that and see if that helps?
>>> 
>>> 
>>> -----Message d'origine-----
>>> De : Gordan Bobic <gordan.bobic@xxxxxxxxx>
>>> Envoyé : mercredi 27 juillet 2022 14:29
>>> À : Marko Mäkelä <marko.makela@xxxxxxxxxxx>
>>> Cc : Cédric Counotte <cedric.counotte@xxxxxxxxxx>; Mailing-List mariadb <maria-discuss@xxxxxxxxxxxxxxxxxxx>
>>> Objet : Re: [Maria-discuss] MariaDB server horribly slow on start
>>> 
>>> On Wed, Jul 27, 2022 at 3:08 PM Marko Mäkelä <marko.makela@xxxxxxxxxxx> wrote:
>>>> 
>>>> On Wed, Jul 27, 2022 at 2:48 PM Gordan Bobic <gordan.bobic@xxxxxxxxx> wrote:
>>>>> 
>>>>> There is no supported downgrade path other than logical dump+restore.
>>>>> There are also no packages built for distros where the major version is older than what ships with the distro.
>>>>> 
>>>>> Since your queries seem to end up stuck in commit stage, it could be related to redo log flushing, which behaves very erratically on 10.5+. If it leaves the log to fill up to 90% and the state transfer hits, it could be that with the checkpoint age already high, there just isn't enough headroom to avoid a massive stall. Purely guessing here without any telemetry.
>>>> 
>>>> I think that you may refer to InnoDB page flushing. There was some
>>>> misunderstanding around that, and indeed some partly unintended or
>>>> uninformed changes in behaviour (in 10.5.7 and 10.5.8) that were
>>>> reverted later. It could be useful to read
>>>> https://jira.mariadb.org/browse/MDEV-27295.
>>> 
>>> What version was it reverted in?
>>> I am still seeing the errant redo log flushing behaviour in 10.5.15.
>>> It looks like no flushing happens until the hwm is reached at about 85% full. It then tries to commit everything down to the lwm. And inbetween it doesn't do anything, even while everything is idle and it should be running down the
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>>