Re: A few new options for CHECKPOINT

On 11/24/20, 4:03 PM, "tsunakawa(dot)takay(at)fujitsu(dot)com" <tsunakawa(dot)takay(at)fujitsu(dot)com> wrote:
> From: Bossart, Nathan <bossartn(at)amazon(dot)com>
>> The main purpose of this patch is to give users more control over their manually
>> requested checkpoints or restartpoints. I suspect the most useful option is
>> IMMEDIATE, which can help avoid checkpoint- related IO spikes. However, I
>> didn't see any strong reason to prevent users from also adjusting FORCE and
>> WAIT.
>
> I think just IMMEDIATE would suffice, too. But could you tell us why you got to want to give users more control? Could we know concrete example situations where users want to perform CHECKPOINT with options?

It may be useful for backups taken with the "consistent snapshot"
approach. As noted in the documentation [0], running CHECKPOINT
before taking the snapshot can reduce recovery time. However, users
might wish to avoid the IO spike caused by an immediate checkpoint.

Nathan

[0] https://www.postgresql.org/docs/devel/backup-file.html