Re: Report checkpoint progress in server logs

On Wed, Dec 29, 2021 at 10:40:59AM -0500, Tom Lane wrote:
> Magnus Hagander <magnus(at)hagander(dot)net> writes:
> >> Therefore, reporting the checkpoint progress in the server logs, much
> >> like [1], seems to be the best way IMO.
>
> > I find progress reporting in the logfile to generally be a terrible
> > way of doing things, and the fact that we do it for the startup
> > process is/should be only because we have no other choice, not because
> > it's the right choice.
>
> I'm already pretty seriously unhappy about the log-spamming effects of
> 64da07c41 (default to log_checkpoints=on), and am willing to lay a side
> bet that that gets reverted after we have some field experience with it.
> This proposal seems far worse from that standpoint. Keep in mind that
> our out-of-the-box logging configuration still doesn't have any log
> rotation ability, which means that the noisier the server is in normal
> operation, the sooner you fill your disk.

I think we are looking at three potential observable behaviors people
might care about:

* the current activity/progress of checkpoints
* the historical reporting of checkpoint completion, mixed in with other
log messages for later analysis
* the aggregate behavior of checkpoint operation

I think it is clear that checkpoint progress activity isn't useful for
the server logs because that information has little historical value,
but does fit for a progress view. As Tom already expressed, we will
have to wait to see if non-progress checkpoint information in the logs
has sufficient historical value.

--
Bruce Momjian <bruce(at)momjian(dot)us> https://momjian.us
EDB https://enterprisedb.com

If only the physical world exists, free will is an illusion.