Re: autoanalyze did not run

On Tue, Jan 27, 2026 at 1:40 PM Олег Самойлов <splarv(at)ya(dot)ru> wrote:
> ----------------
> Кому: Олег Самойлов (splarv(at)ya(dot)ru), Pgsql-admin (pgsql-admin(at)lists(dot)postgresql(dot)org);
> Тема: autoanalyze did not run;
> 26.01.2026, 19:03, "Laurenz Albe" <laurenz(dot)albe(at)cybertec(dot)at>:
>
> On Mon, 2026-01-26 at 17:35 +0300, Олег Самойлов wrote:
>
> > > I try to investigate why autoanalyze did not run in time of our initial
> > > loading data. Yes, I know, running analyze manually is highly
> > > recommended in such case. But is must run automatically too.
> > >
> > > PostgreSQL 17.7 (Debian 17.7-3.pgdg13+1) on x86_64-pc-linux-gnu,
> > > compiled by gcc (Debian 14.2.0-19) 14.2.0, 64-bit (from PGDG)
> >
> > Are you sure that you committed the transaction?
>
> I am very sure, thats why there are 13844347 rows in that table. By single copy.
> >
> > Is "track_activities" set to "on"?
>
> I checked, yep.
>
>
> Then the only explanation is that all autovacuum workers are active, and this
> table is starved. See how many autovacuum workers are visible in pg_stat_activity
> and compare that to autovacuum_max_workers.
>
> Yours,
> Laurenz Albe
>
> Now 0. But they worked. The reason is other. Look, first of all, there was not a statistic reset.
> SELECT stats_reset is null FROM pg_stat_database WHERE datname = current_database();
> ?column?\c
> ----------
> t
> (1 row)
> select analyze_count,autoanalyze_count,reltuples, n_live_tup, n_tup_ins, n_tup_upd, n_mod_since_analyze from pg_stat_user_tables as s join pg_class as c on (s.relid=c.oid) where relkind='r' and reltuples>0 limit 10;
> analyze_count | autoanalyze_count | reltuples | n_live_tup | n_tup_ins | n_tup_upd | n_mod_since_analyze
> ---------------+-------------------+---------------+------------+-----------+-----------+---------------------
> 0 | 0 | 8 | 0 | 0 | 0 | 0
> 0 | 0 | 76596 | 0 | 0 | 0 | 0
> 0 | 0 | 140997 | 0 | 0 | 0 | 0
> 0 | 0 | 2.088436e+07 | 0 | 0 | 0 | 0
> 0 | 0 | 1.2661012e+07 | 0 | 0 | 0 | 0
> 0 | 0 | 2.288401e+07 | 0 | 0 | 0 | 0
> 0 | 0 | 99926 | 0 | 0 | 0 | 0
> 0 | 0 | 1.5620866e+07 | 0 | 0 | 0 | 0
> 0 | 0 | 17511 | 0 | 0 | 0 | 0
> 0 | 0 | 400926 | 0 | 0 | 0 | 0
> The reason is the n_mod_since_analyze is 0. Thats why autoanalyze didn't started.

Hello,

I do apologize if I mix something up now, but I would expect COPY to
have an effect on "n_ins_since_vacuum" but not "n_mod_since_analyze".
COPY inserts rows, it does not update them.

With best regards,
--
Kristjan Mustkivi

Email: kristjan(dot)mustkivi(at)gmail(dot)com