maria-discuss team mailing list archive

[Cédric Counotte <cedric.counotte@xxxxxxxxxx>]

Considering the binlog files are 1GB and I get 144 of them per day, doesn't it mean that my 1GB log file holds about 10 minutes only of logs?



I suppose I should make it 6GB then to follow that article 😉



Still using galera, I assume crashes are compensated by another node and 1GB of log should be enough for now.



FWIW Servers are using NVMe from OVH, 4 of them are on ovh gen 2 NVMe (whatever it means).





-----Message d'origine-----
De : jocelyn fournier <jocelyn.fournier@xxxxxxxxx>
Envoyé : mercredi 27 juillet 2022 15:26
À : Gordan Bobic <gordan.bobic@xxxxxxxxx>
Cc : Cédric Counotte <cedric.counotte@xxxxxxxxxx>; Marko Mäkelä <marko.makela@xxxxxxxxxxx>; Mailing-List mariadb <maria-discuss@xxxxxxxxxxxxxxxxxxx>; Pierre LAFON <pierre.lafon@xxxxxxxxxx>
Objet : Re: [Maria-discuss] MariaDB server horribly slow on start



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<mailto: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<mailto: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<mailto: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<mailto:gordan.bobic@xxxxxxxxx>> Envoyé : mercredi 27

>>> juillet 2022 14:29 À : Marko Mäkelä <marko.makela@xxxxxxxxxxx<mailto:marko.makela@xxxxxxxxxxx>> Cc :

>>> Cédric Counotte <cedric.counotte@xxxxxxxxxx<mailto:cedric.counotte@xxxxxxxxxx>>; Mailing-List mariadb

>>> <maria-discuss@xxxxxxxxxxxxxxxxxxx<mailto: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<mailto:marko.makela@xxxxxxxxxxx>> wrote:

>>>>

>>>> On Wed, Jul 27, 2022 at 2:48 PM Gordan Bobic <gordan.bobic@xxxxxxxxx<mailto: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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>>