Message-ID: <0dce35ca-24fa-4234-99fe-071bd5725a32@ya.ru>
Date: Mon, 26 Jan 2026 08:31:24 +0300
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From: =?UTF-8?B?0J7Qu9C10LMg0KHQsNC80L7QudC70L7Qsg==?= <splarv@ya.ru>
Subject: autoanalyze did not run
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Hi, all.

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. Or it us 
bugged?
Initial loading data made by COPY command. After this (and after all 
autovacuum) I see:

select c.relkind, count(*) from pg_stat_user_tables as s join pg_class 
as c on (s.relid=c.oid) where s.autoanalyze_count=0 and s.n_live_tup>0 
group by c.relkind;
-[ RECORD 1 ]-
relkind | r
count   | 1069

More investigation:

select relid::regclass, 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 s.autoanalyze_count=0 and relkind='r' and 
n_live_tup>0 limit 1;
-[ RECORD 1 ]-------+----------
relid               | addresses
n_live_tup          | 13844405
n_tup_ins           | 0
n_tup_upd           | 0
n_mod_since_analyze | 0

select count(*) from addresses;
-[ RECORD 1 ]---
count | 13844347

This is example for only 1 table, but there are one thousand such. What 
is exact criteria to launch autoanalyze? On columns of 
pg_stat_user_tables it is based? If only on n_mod_since_analyze, there 
can be a logical trap (bug), analyze will have 
always n_mod_since_analyze=0 on tables where it never yet ran, so it 
will not run. Or may be there is an other reason?

I am afraid that this bug can be not only on initial loading, but in 
normal work 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)