Re: [HACKERS] More stats about skipped vacuums

On Sun, Nov 26, 2017 at 12:34 AM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Michael Paquier <michael(dot)paquier(at)gmail(dot)com> writes:
>> On Sat, Nov 25, 2017 at 12:55 AM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>>> I think that's a good thing to worry about. In the past, Tom has
>>> expressed reluctance to make stats tables that have a row per table
>>> any wider at all, IIRC.
>
>> Tom, any opinions to offer here? pg_stat_all_tables is currently at 22
>> columns (this takes two full lines on my terminal with a font size at
>> 13). With the first patch of what's proposed on this thread there
>> would be 24 columns. Perhaps it would be time to split the vacuum
>> statistics into a new view like pg_stat_tables_vacuum or similar?
>
> My concern is not with the width of any view --- you can always select a
> subset of columns if a view is too wide for your screen. The issue is the
> number of counters in the stats collector's state. We know, without any
> doubt, that widening PgStat_StatTabEntry causes serious pain to people
> with large numbers of tables; and they have no recourse when we do it.
> So the bar to adding more counters is very high IMO. I won't say never,
> but I do doubt that something like skipped vacuums should make the cut.

I am not arguing about skipped vacuuum data here (don't think much of
it by the way), but of the number of index scans done by the last
vacuum or autovacuum. This helps in tunning autovacuum_work_mem and
maintenance_work_mem. The bar is still too high for that?
--
Michael