Message-ID: <98b2fcf0-f701-369e-d63d-6be9739ce17c@gmail.com>
Date: Sun, 27 Oct 2024 14:00:00 +0300
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Subject: Re: Statistics Import and Export
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To: Jeff Davis <pgsql@j-davis.com>, Corey Huinker <corey.huinker@gmail.com>,
 jian he <jian.universality@gmail.com>
Cc: Matthias van de Meent <boekewurm+postgres@gmail.com>,
 Bruce Momjian <bruce@momjian.us>, Tom Lane <tgl@sss.pgh.pa.us>,
 Nathan Bossart <nathandbossart@gmail.com>,
 Magnus Hagander <magnus@hagander.net>, Stephen Frost <sfrost@snowman.net>,
 Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>,
 Peter Smith <smithpb2250@gmail.com>,
 PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>,
 alvherre@alvh.no-ip.org
References: <e8135244d99e6bc388853598cb0ec4bf59085494.camel@j-davis.com>
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 <e1c15b4eb1472f5bba9d61315b3fc2fb7484d8a4.camel@j-davis.com>
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From: Alexander Lakhin <exclusion@gmail.com>
In-Reply-To: <be7de51af6e969d501f69426c7137af6bde17fdc.camel@j-davis.com>
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Hello Jeff and Corey,

26.10.2024 01:18, Jeff Davis wrote:
> On Tue, 2024-09-17 at 05:02 -0400, Corey Huinker wrote:
>> I've taken most of Jeff's work, reincorporated it into roughly the
>> same patch structure as before, and am posting it now.
> I have committed the import side of this patch series; that is, the
> function calls that can load stats into an existing cluster without the
> need to ANALYZE.
>
> The pg_restore_*_stats() functions are designed such that pg_dump can
> emit the calls. Some design choices of the functions worth noting:

Please look at the following seemingly atypical behavior of the new
functions:
CREATE TABLE test(id int);

SELECT pg_restore_attribute_stats(
   'relation', 'test'::regclass,
   'attname', 'id'::name,
   'inherited', false);

SELECT pg_restore_attribute_stats(
   'relation', 'test'::regclass,
   'attname', 'id'::name,
   'inherited', false
) FROM generate_series(1, 2);
ERROR:  XX000: tuple already updated by self
LOCATION:  simple_heap_update, heapam.c:4353

Or:
SELECT pg_clear_attribute_stats('test'::regclass, 'id'::name, false)
FROM generate_series(1, 2);
ERROR:  XX000: tuple already updated by self
LOCATION:  simple_heap_delete, heapam.c:3108

Best regards,
Alexander