Message-ID: <edff64df-da98-4d1d-a65a-6f5a8edf7d92@postgrespro.ru>
Date: Fri, 7 Nov 2025 18:19:39 +0300
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Subject: Re: Incorrect checksum in control file with pg_rewind test
From: "Maksim.Melnikov" <m.melnikov@postgrespro.ru>
To: pgsql-hackers@lists.postgresql.org
References: <f59335a4-83ff-438a-a30e-7cf2200276b6@postgrespro.ru>
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Hi,
just to clarify, it isn't pg_rewind related issue and can fire=20
spontaneously.
I don't have any strong scenario how to reproduce it, tests sometimes=20
fired on our local CI, but as you can see on thread [1],
where the same issue for frontends was discussed, it is very hard to=20
reproduce and there wasn't scenario how to do it too.

Some dirty hacks to reproduce it was described here [2], and I've tried=20
it on master branch:
First of all I applied patch=20
0001-XXX-Dirty-hack-to-clobber-control-file-for-testing.patch from [2],=20
then compile app with
-DEXEC_BACKEND and exec command in psql
do $$ begin loop perform pg_update_control_file(); end loop; end; $$;
Also I've run pgbench command
for run in {1..5000}; do pgbench -c50 -t100 -j6 -S postgres ; done
And eventually got error

2025-11-07 17:58:33.139 MSK [2472504] FATAL:=C2=A0 incorrect checksum in=20
control file
2025-11-07 17:58:33.141 MSK [2472501] LOG:=C2=A0 could not receive data f=
rom=20
client: Connection reset by peer
2025-11-07 17:58:33.143 MSK [2472505] LOG:=C2=A0 could not send data to=20
client: Broken pipe
2025-11-07 17:58:33.143 MSK [2472505] FATAL:=C2=A0 connection to client l=
ost

Best regards,
Maksim Melnikov

[1]=20
https://www.postgresql.org/message-id/flat/20221123014224.xisi44byq3cf5ps=
i%40awork3.anarazel.de
[2]=20
https://www.postgresql.org/message-id/CA%2BhUKGK-BEe38aKNqHJDQ86LUW-CMwF5=
F9bo1JtJVg71FoDv_w%40mail.gmail.com
[3]=20
https://www.postgresql.org/message-id/f59335a4-83ff-438a-a30e-7cf2200276b=
6%40postgrespro.ru