Message-ID: <37c3bd11-7321-fe58-99ca-bc15a67c08cc@gmail.com>
Date: Sat, 31 Aug 2024 07:04:04 +0300
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101
 Thunderbird/102.4.2
Subject: Re: [EXTERNAL] Re: Add non-blocking version of PQcancel
Content-Language: en-US
To: Tom Lane <tgl@sss.pgh.pa.us>, Jelte Fennema-Nio <postgres@jeltef.nl>
Cc: Alvaro Herrera <alvherre@alvh.no-ip.org>, Noah Misch <noah@leadboat.com>,
 Jacob Champion <jacob.champion@enterprisedb.com>,
 Denis Laxalde <denis.laxalde@dalibo.com>, vignesh C <vignesh21@gmail.com>,
 Thomas Munro <thomas.munro@gmail.com>, Greg Stark <stark@mit.edu>,
 "Gregory Stark (as CFM)" <stark.cfm@gmail.com>,
 Jelte Fennema <Jelte.Fennema@microsoft.com>,
 Daniel Gustafsson <daniel@yesql.se>, Peter Eisentraut
 <peter@eisentraut.org>, Andres Freund <andres@anarazel.de>,
 Justin Pryzby <pryzby@telsasoft.com>, Robert Haas <robertmhaas@gmail.com>,
 PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>,
 Etsuro Fujita <etsuro.fujita@gmail.com>
References: <202407221126.vyw5q3h4nyoh@alvherre.pgsql>
 <5ea25e4d-1ee2-b9bf-7806-119ffa658826@gmail.com>
 <578934.1725045685@sss.pgh.pa.us>
 <CAGECzQQZi_po92DSgo75vmM-KxG2zMGzo-tt+Z+85w3BgL89ug@mail.gmail.com>
 <584811.1725048717@sss.pgh.pa.us> <591893.1725051309@sss.pgh.pa.us>
From: Alexander Lakhin <exclusion@gmail.com>
In-Reply-To: <591893.1725051309@sss.pgh.pa.us>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit
Archived-At: 
 <https://www.postgresql.org/message-id/37c3bd11-7321-fe58-99ca-bc15a67c08cc%40gmail.com>
Precedence: bulk

Hello Tom,

30.08.2024 23:55, Tom Lane wrote:
> Pushed with that addition and some comment-tweaking.  We'll see
> whether that actually makes things more stable, but I don't think
> it could make it worse.

Thank you for fixing that issue!

I've tested your fix with the modification I proposed upthread:
              idle_session_timeout_enabled = false;
          }
+if (rand() % 10 == 0) pg_usleep(10000);
          /*
           * (5) disable async signal conditions again.

and can confirm that the issue is gone. On 8749d850f~1, the test failed
on iterations 3, 3. 12 for me, but on current REL_17_STABLE, 100 test
iterations succeeded.

At the same time, mylodon confirmed my other finding at [1] and failed [2] with:
-ERROR:  canceling statement due to statement timeout
+ERROR:  canceling statement due to user request

[1] https://www.postgresql.org/message-id/4db099c8-4a52-3cc4-e970-14539a319466%40gmail.com
[2] https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=mylodon&dt=2024-08-30%2023%3A03%3A31

Best regards,
Alexander