Re: Expose checkpoint start/finish times into SQL.

Tom Lane wrote:
> Greg Smith <gsmith(at)gregsmith(dot)com> writes:
> > ... If they'd have noticed it while the server was up, perhaps because the
> > "last checkpoint" value hadn't changed in a long time (which seems like it
> > might be available via stats even if, as you say, the background writer is
> > out of its mind at that point), they could have done such a kill and
> > collected some actual useful information here. That's the theory at
> > least.
>
> Well, mebbe, but that still seems to require a lot of custom monitoring
> infrastructure that is not present in this patch, and furthermore that
> this patch doesn't especially aid the development of.

These kind of things can be monitored externally very easily, say by
Nagios, when the values are available via the database. If you have to
troll the logs, it's quite a bit harder to do it.

I'm not sure about the right values to export -- last checkpoint start
time is the most obvious idea, but I would also suggest exporting last
checkpoint end, or NULL if the checkpoint is ongoing; and also previous-
to-last checkpoint start and end.

--
Alvaro Herrera http://www.CommandPrompt.com/
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