Message-ID: <918f94be-41b9-e684-7679-b6bd819f693c@gmail.com>
Date: Mon, 21 Aug 2023 20:09:03 +0400
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Subject: Re: Why doesn't autovacuum/analyze run in due time after calling
 pg_stat_reset?
To: Adrian Klaver <adrian.klaver@aklaver.com>,
 pgsql-general General <pgsql-general@postgresql.org>
References: <69eacc0a-7e9b-4a35-278b-110b93d72882@mail.ru>
 <18167fbd-815f-9b43-7016-5e5bbb8fb255@gmail.com>
 <9440ab9c-4ee1-7668-5476-dc28e8086524@aklaver.com>
 <c1d7097c-710a-9513-7831-c765a2b622bf@gmail.com>
 <b0bb3ee4-e26c-941a-b326-68b515a09006@aklaver.com>
 <db75baff-dbc7-ee53-6b06-73455428358d@gmail.com>
 <b020c3de-4399-4d35-8dd7-cb64a3a77627@aklaver.com>
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From: Rihad <grihad@gmail.com>
In-Reply-To: <b020c3de-4399-4d35-8dd7-cb64a3a77627@aklaver.com>
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On 8/21/23 20:00, Adrian Klaver wrote:
> On 8/20/23 22:31, Rihad wrote:
>> On 8/21/23 00:15, Adrian Klaver wrote:
>>> On 8/20/23 12:10, Rihad wrote:
>>>> On 8/20/23 20:22, Adrian Klaver wrote:
>>>>> On 8/18/23 22:35, Rihad wrote:
>>>>>> On 8/17/23 13:01, rihad wrote:
>>>>>>>
>
>>>
>>> Hard to say without seeing the actual settings in postgresql.conf 
>>> that match:
>>>
>>> https://www.postgresql.org/docs/current/runtime-config-autovacuum.html#GUC-AUTOVACUUM-VACUUM-SCALE-FACTOR 
>>>
>>>
>>>
>>> Most importantly:
>>>
>>> autovacuum
>>>
>>> and
>>>
>>> track_counts
>>>
>>> https://www.postgresql.org/docs/current/runtime-config-statistics.html#GUC-TRACK-COUNTS 
>>>
>>>
>>
>> They are both on and set as per default. Autovac/analyze continue 
>> running on some tables after pg_stat_reset. Just not on all of them, 
>> even thought they should judging by live/dead tuples calculation.
>>
>>
>> foo=> show track_counts;
>> track_counts
>> --------------
>> on
>> (1 row)
>>
>> foo=> show autovacuum;
>> autovacuum
>> ------------
>> on
>> (1 row)
>
> How about the rest of the settings at?:
>
> https://www.postgresql.org/docs/current/runtime-config-autovacuum.html
>
> Have the storage parameters for the tables been changed per?:
>
> https://www.postgresql.org/docs/current/sql-createtable.html#SQL-CREATETABLE-STORAGE-PARAMETERS 
>
>
> In psql you can do:
>
> \d+ <table_name>
>
> The setting if changed will show up as Options: <setting>
>
> Also are there include directives in use per?:
>
> https://www.postgresql.org/docs/current/config-setting.html#CONFIG-INCLUDES 
>
>
> You can see by looking at the sourcefile field in pg_settings:
>
> https://www.postgresql.org/docs/current/view-pg-settings.html
>
Thanks for the detailed reply, no tables have custom settings.

I need to make it clear once again that all autovac/analyze work as 
expected when n_live_tup matches reality, i.e. when analyze has been run 
on them since last reset.

A way to fix this is to simply analyze the whole database. Before doing 
that, while n_live_tup starts from basically 0 and grows based on DB 
activity, these usual calculations of 10-20% table size for 
vacuum/analyze don't work. They don't trigger autovac for most tables, 
or do it much much later.


>>
>>
>>>>
>>>>
>>>>>
>>>>>>
>>>>>> There are still many tables waiting for their turn, which is long 
>>>>>> due.
>>>>>>
>>>>>> Although there are some tables having only 60-70 (not 60-70K) 
>>>>>> n_live_tup that have had autovacuum run on them. Weird.
>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>
>>>
>>
>