From: Tom Lane <tgl@sss.pgh.pa.us>
To: Justin Pryzby <pryzby@telsasoft.com>
cc: Alexander Lakhin <exclusion@gmail.com>,
        Alvaro Herrera <alvherre@alvh.no-ip.org>,
        Michael Paquier <michael@paquier.xyz>,
        Peter Eisentraut <peter@eisentraut.org>,
        Soumyadeep Chakraborty <soumyadeep2007@gmail.com>,
        Zhihong Yu <zyu@yugabyte.com>, pgsql-hackers@postgresql.org,
        Ashwin Agrawal <ashwinstar@gmail.com>, vanjared@vmware.com
Subject: Re: ALTER TABLE SET ACCESS METHOD on partitioned tables
In-reply-to: <ZglExpzL9w0MtBWf@pryzbyj2023>
References: <202403281558.xk5pgf7ur3dq@alvherre.pgsql> <f3e61e27-19d0-5e40-3eb2-53282fa0532a@gmail.com> <ZglExpzL9w0MtBWf@pryzbyj2023>
Comments: In-reply-to Justin Pryzby <pryzby@telsasoft.com>
	message dated "Sun, 31 Mar 2024 06:11:02 -0500"
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Date: Tue, 02 Apr 2024 01:06:06 -0400
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Justin Pryzby <pryzby@telsasoft.com> writes:
> On Sun, Mar 31, 2024 at 12:00:00PM +0300, Alexander Lakhin wrote:
>> I've stumbled upon a test failure caused by the test query added in tha=
t
>> commit:
>> +ERROR:=C2=A0 deadlock detected
>> +DETAIL:=C2=A0 Process 3076180 waits for AccessShareLock on relation 12=
59 of database 16386; blocked by process 3076181.
>> +Process 3076181 waits for AccessShareLock on relation 2601 of database=
 16386; blocked by process 3076180.

> I think means that, although it was cute to use pg_am in the reproducer
> given in the problem report, it's not a good choice to use here in the
> sql regression tests.

Another case here:

https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=3Dsevengill&dt=3D2=
024-04-02%2001%3A32%3A17

AFAICS, e2395cdbe posits that taking exclusive lock on pg_am in the
middle of a bunch of concurrent regression scripts couldn't possibly
cause any problems.  Really?

			regards, tom lane