Re: Proposal: Log inability to lock pages during vacuum

On 2014-11-10 15:36:55 -0300, Alvaro Herrera wrote:
> Andres Freund wrote:
> > On 2014-11-10 14:28:30 -0300, Alvaro Herrera wrote:
> 
> > > 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.
> 
> We already have "last_autovacuum" columns and such in pg_stat_tables et
> al, which only record the last value.  My thinking regarding such
> numbers is that you would save histories and put them in a chart, see
> how they evolve with time.  I doubt the individual numbers are worth
> much, but the trends might show something interesting.

I don't think they mean anything without also reporting the number of
buffers actually scanned and other related stats.

Greetings,

Andres Freund

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