Re: [Maria-discuss] MariaDB server horribly slow on start

27 Jul 2022

      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@gmail.com>
Envoyé : mercredi 27 juillet 2022 15:26
À : Gordan Bobic <gordan.bobic@gmail.com>
Cc : Cédric Counotte <cedric.counotte@1check.com>; Marko Mäkelä <marko.makela@mariadb.com>; Mailing-List mariadb <maria-discuss@lists.launchpad.net>; Pierre LAFON <pierre.lafon@1check.com>
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-f...

If you don’t need a big redo log, reduce its side to avoid slow crash recovery
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Le 27 juil. 2022 à 15:23, Gordan Bobic <gordan.bobic@gmail.com<mailto:gordan.bobic@gmail.com>> a écrit :
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10.5+ only uses a single log file, so that is 1x1GB.
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And 1GB is tiny, IMO it should be a default these days.
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I would only even consider something smaller if I was running on an
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older Raspberry Pi or something similarly constrained.
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On Wed, Jul 27, 2022 at 4:11 PM jocelyn fournier
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<jocelyn.fournier@gmail.com<mailto:jocelyn.fournier@gmail.com>> wrote:
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Hi Cédric!
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Just to be sure, do you really need the 2x 1G log_file_size ?
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BR,
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Jocelyn Fournier
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Le 27 juil. 2022 à 14:36, Cédric Counotte <cedric.counotte@1check.com<mailto:cedric.counotte@1check.com>> a écrit :
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Reading this: https://jira.mariadb.org/browse/MDEV-27295
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It's quite unclear when it is fixed or reverted.
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That said I read that the following setting might fix it:
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SET GLOBAL innodb_max_dirty_pages_pct_lwm=0.001;
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Is that correct and should I try that and see if that helps?
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-----Message d'origine-----
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De : Gordan Bobic <gordan.bobic@gmail.com<mailto:gordan.bobic@gmail.com>> Envoyé : mercredi 27
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juillet 2022 14:29 À : Marko Mäkelä <marko.makela@mariadb.com<mailto:marko.makela@mariadb.com>> Cc :
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Cédric Counotte <cedric.counotte@1check.com<mailto:cedric.counotte@1check.com>>; Mailing-List mariadb
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<maria-discuss@lists.launchpad.net<mailto:maria-discuss@lists.launchpad.net>>
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Objet : Re: [Maria-discuss] MariaDB server horribly slow on start
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On Wed, Jul 27, 2022 at 3:08 PM Marko Mäkelä <marko.makela@mariadb.com<mailto:marko.makela@mariadb.com>> wrote:
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On Wed, Jul 27, 2022 at 2:48 PM Gordan Bobic <gordan.bobic@gmail.com<mailto:gordan.bobic@gmail.com>> wrote:
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There is no supported downgrade path other than logical dump+restore.
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There are also no packages built for distros where the major version is older than what ships with the distro.
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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.
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I think that you may refer to InnoDB page flushing. There was some
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misunderstanding around that, and indeed some partly unintended or
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uninformed changes in behaviour (in 10.5.7 and 10.5.8) that were
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reverted later. It could be useful to read
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https://jira.mariadb.org/browse/MDEV-27295.
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What version was it reverted in?
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I am still seeing the errant redo log flushing behaviour in 10.5.15.
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It looks like no flushing happens until the hwm is reached at about
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85% full. It then tries to commit everything down to the lwm. And
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inbetween it doesn't do anything, even while everything is idle and
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it should be running down the
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