maria-discuss team mailing list archive

[Gordan Bobic <gordan.bobic@xxxxxxxxx>]

On Wed, Jan 18, 2023 at 4:30 PM Marko Mäkelä <marko.makela@xxxxxxxxxxx> wrote:

> It should be worth noting that starting with MariaDB 10.5, there will
> no longer be writes of garbage pages that were freed from the
> underlying file, for example, as part of DROP INDEX, TRUNCATE TABLE,
> or a massive DELETE.
>
> In https://jira.mariadb.org/browse/MDEV-19895 I would welcome
> constructive feedback on how to set sane default values of some
> parameters, based on a small number of parameters, say, the available
> size of memory, CPU cores, storage, and the size of the database.

May or may not be directly related to this, but with 10.5+ I see the
checkpoint age exhibiting a sawtooth pattern - nothing gets flushed
until it gets near the log capacity, then there is a huge burst of
writes and it crashes down to a sensible level.
Prior to 10.5, the checkpoint age remains low unless the workload is
overruning innodb_io_capacity.

I get the motivation to reduce flushing, but if the checkpoint age is
already close to the high water mark and a sustained high volume of
transactions hits, then the server has nowhere to go because it has
already used up all of it's scope for absorbing the shock into the
redo log and everything grinds to a halt.
Is there a way to restore the old behaviour? The new behaviour seems
to be in all 10.5+ versions I looked at.