Re: Proposal: Log inability to lock pages during vacuum

On 2014-11-10 14:28:30 -0300, Alvaro Herrera wrote:
> Jim Nasby wrote:
> > On 11/7/14, 8:21 PM, Robert Haas wrote:
> > >On Thu, Nov 6, 2014 at 8:03 PM, Jim Nasby <Jim(dot)Nasby(at)bluetreble(dot)com> wrote:
> > >>The problem right now is there's no way to actually obtain evidence that
> > >>this is (or isn't) something to worry about, because we just silently skip
> > >>pages. If we had any kind of tracking on this we could stop guessing. :(
> > >
> > >I could see logging it, but I agree with Andres and Alvaro that the
> > >odds are strongly against there being any actual problem here.
> >
> > I'm fine with that. Any other objections? Andres?

If you feel that strong about the need for logging, go ahead.

> If what we want is to quantify the extent of the issue, would it be more
> convenient to save counters to pgstat? Vacuum already sends pgstat
> messages, so there's no additional traffic there.

I'm pretty strongly against that one in isolation. They'd need to be
stored somewhere and they'd need to be queryable somewhere with enough
context to make sense. To actually make sense of the numbers we'd also
need to report all the other datapoints of vacuum in some form. That's
quite a worthwile project imo - but *much* *much* more work than this.

Greetings,

Andres Freund

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