maria-discuss team mailing list archive

[Gordan Bobic <gordan.bobic@xxxxxxxxx>]

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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