maria-discuss team mailing list archive

[Gordan Bobic <gordan.bobic@xxxxxxxxx>]

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