Date: Tue, 28 Jan 2020 18:07:55 +0100
From: Tomas Vondra <tomas.vondra@2ndquadrant.com>
To: Oleksii Kliukin <alexk@hintbits.com>
Cc: pgsql-bugs@lists.postgresql.org, ildus@adjust.com,
	Chris Travers <chris.travers@adjust.com>,
	Nick Babadzhanian <nickb@adjust.com>, julian.schauder@gmx.de
Subject: Re: postgres crash on concurrent update of inheritance partitioned
 table
Message-ID: <20200128170755.bq3f27bfkjpt4d4b@development>
References: <EEF05F66-2871-4786-992B-5F45C92FEE2E@hintbits.com>
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On Tue, Jan 28, 2020 at 05:17:14PM +0100, Oleksii Kliukin wrote:
>Hello there,
>
>We have experienced a few crashes a day since upgrading to pg 12.1 last
>week, during the process of updating an inheritance-partitioned table by
>several concurrent sessions.
>
>Here’s the reproducer that consistency crashes pg 12.1 (and master) on my
>machine.
>
>Setup:
>
>create table p(flag boolean);
>create table c1() inherits(p);
>create table c2() inherits(p);
>insert into c1 select false from generate_series(1,10);
>insert into c2 select false from generate_series(1,10);
>
>session 1:					session 2:
>begin;						begin
>update p set flag = true;						
>							update p set flag = true;
>commit;						server closed the connection unexpectedly
>								This probably means the server terminated abnormally
>								before or while processing the request.
>							The connection to the server was lost. Attempting reset: Failed.
>

Yeah, I can reproduce it too. If I had to guess, I'd say it's another
bug due to 

     commit 3fb307bc4a76815f96fec28a0d1525ab3fbbcfb4
     Author: Andres Freund <andres@anarazel.de>
     Date:   Mon Sep 9 05:21:30 2019 -0700

     Reorder EPQ work, to fix rowmark related bugs and improve efficiency.

which introduced relsubs_done et al, and perhaps did not get the life
cycle / resetting right. Not sure.


regards

-- 
Tomas Vondra                  http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services