Re: Report checkpoint progress with pg_stat_progress_checkpoint (was: Report checkpoint progress in server logs)

On Wed, Mar 2, 2022 at 7:15 PM Nitin Jadhav
<nitinjadhavpostgres(at)gmail(dot)com> wrote:
>
> > > > As mentioned upthread, there can be multiple backends that request a
> > > > checkpoint, so unless we want to store an array of pid we should store a number
> > > > of backend that are waiting for a new checkpoint.
>
> It's a good metric to show in the view but the information is not
> readily available. Additional code is required to calculate the number
> of requests. Is it worth doing that? I feel this can be added later if
> required.

Is it that hard or costly to do? Just sending a message to increment
the stat counter in RequestCheckpoint() would be enough.

Also, unless I'm missing something it's still only showing the initial
checkpoint flags, so it's *not* showing what the checkpoint is really
doing, only what the checkpoint may be doing if nothing else happens.
It just feels wrong. You could even use that ckpt_flags info to know
that at least one backend has requested a new checkpoint, if you don't
want to have a number of backends.