Re: PATCH: regular logging of checkpoint progress

"Tomas Vondra" <tv(at)fuzzy(dot)cz> writes:
> On 2 Z 2011, 20:48, Tom Lane wrote:
>> Yeah, if we're going to have this at all, some form of GUC control over
>> it seems necessary. I'm still disturbed by the verbosity of the
>> proposed output though. Couldn't we collapse the information into a
>> single log entry per checkpoint cycle? Perhaps that would be sufficient
>> to just let the log_checkpoints setting be used as-is.

> I'm not sure what you mean by collapsing the info into a single log entry?
> That would mean I'd have to wait till the checkpoint completes, and one of
> the reasons for this patch was to get info about progress while the
> checkpoint is running.

Well, to be blunt, putting stuff into the postmaster log is entirely the
wrong way to satify a requirement like that. If you want to expose
progress information, it should be exposed via something dynamic like
pg_stat_activity. What could be useful to log is statistics that people
might want to aggregate later, and I don't immediately see a reason why
such stats couldn't be logged just once at end of each checkpoint cycle.

regards, tom lane