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From: Shlok Kyal <shlok.kyal.oss@gmail.com>
Date: Wed, 9 Jul 2025 13:57:42 +0530
Message-ID: <CANhcyEXU4qyFZzKB3ByGqdMrM_v7RpowzLhcRVry6WhxBZaeAA@mail.gmail.com>
Subject: =?UTF-8?Q?Re=3A_error_=E2=80=9Cserver_process_was_terminated_by_signal?=
	=?UTF-8?Q?_11=3A_Segmentation_fault=E2=80=9D_running_pg=5Fcreate=5Flogical=5Freplica?=
	=?UTF-8?Q?tion=5Fslot_using_pgoutput_plugin?=
To: abrahim abrahao <a_abrahao@yahoo.com.br>
Cc: "pgsql-general@lists.postgresql.org" <pgsql-general@lists.postgresql.org>
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On Wed, 9 Jul 2025 at 12:19, Shlok Kyal <shlok.kyal.oss@gmail.com> wrote:
>
> On Wed, 9 Jul 2025 at 11:43, abrahim abrahao <a_abrahao@yahoo.com.br> wro=
te:
> >
> > I got error =E2=80=9Cserver process was terminated by signal 11: Segmen=
tation fault=E2=80=9D using pg_create_logical_replication_slot with pgoutpu=
t plugin parameter and using test_decoding worked fine, any idea that is wr=
ong?
> >
> > Note: I am using docker container and I also updated shm-size from 1024=
mb to 2g and I am using shared_buffers=3D1.5GB.
> > This is a test server and there is nothing else running. IT is the firs=
t time I am working with logical replication.
> >
> > See details below
> >
> > postgresql.conf file:
> > wal_level =3D logical
> > max_replication_slots =3D 10
> > max_wal_senders =3D 20
> > listen_addresses =3D '*'
> >
> >
> >
> >  psql -U postgres -h postgres -c "SELECT pg_create_logical_replication_=
slot('support7561_repslot', 'pgoutput');"
> > SSL SYSCALL error: EOF detected
> > connection to server was lost
> >
> >
> > < 2025-07-08 14:57:08.653 UTC psql postgres postgres 172.18.0.94(53414)=
 SELECT 00000 2025-07-08 14:57:07 UTC 1096 686d31c3.448 2025-07-08 14:57:08=
.653 UTC > LOG:  Initializing CDC decoder
> > < 2025-07-08 14:57:08.653 UTC psql postgres postgres 172.18.0.94(53414)=
 SELECT 00000 2025-07-08 14:57:07 UTC 1096 686d31c3.448 2025-07-08 14:57:08=
.653 UTC > STATEMENT:  SELECT pg_create_logical_replication_slot('support75=
61_repslot', 'pgoutput');
> > < 2025-07-08 14:57:08.821 UTC      00000 2025-07-08 14:55:38 UTC 923 68=
6d316a.39b 2025-07-08 14:57:08.821 UTC > LOG:  server process (PID 1096) wa=
s terminated by signal 11: Segmentation fault
> > < 2025-07-08 14:57:08.821 UTC      00000 2025-07-08 14:55:38 UTC 923 68=
6d316a.39b 2025-07-08 14:57:08.821 UTC > DETAIL:  Failed process was runnin=
g: SELECT pg_create_logical_replication_slot('support7561_repslot', 'pgoutp=
ut');
> > < 2025-07-08 14:57:08.821 UTC      00000 2025-07-08 14:55:38 UTC 923 68=
6d316a.39b 2025-07-08 14:57:08.821 UTC > LOG:  terminating any other active=
 server processes
> > < 2025-07-08 14:57:08.829 UTC      00000 2025-07-08 14:55:38 UTC 923 68=
6d316a.39b 2025-07-08 14:57:08.829 UTC > LOG:  all server processes termina=
ted; reinitializing
> > < 2025-07-08 14:57:09.215 UTC      00000 2025-07-08 14:57:09 UTC 1098 6=
86d31c5.44a 2025-07-08 14:57:09.215 UTC > LOG:  database system was interru=
pted; last known up at 2025-07-08 14:55:39 UTC
> > < 2025-07-08 14:57:10.037 UTC [unknown] postgres postgres 172.18.0.217(=
33506)  57P03 2025-07-08 14:57:10 UTC 1101 686d31c6.44d 2025-07-08 14:57:10=
.037 UTC > FATAL:  the database system is in recovery mode
> > < 2025-07-08 14:57:10.437 UTC      00000 2025-07-08 14:57:09 UTC 1098 6=
86d31c5.44a 2025-07-08 14:57:10.437 UTC > LOG:  database system was not pro=
perly shut down; automatic recovery in progress
> > < 2025-07-08 14:57:10.450 UTC      00000 2025-07-08 14:57:09 UTC 1098 6=
86d31c5.44a 2025-07-08 14:57:10.450 UTC > LOG:  redo starts at 1FB9/C0000A0
> > < 2025-07-08 14:57:10.456 UTC      00000 2025-07-08 14:57:09 UTC 1098 6=
86d31c5.44a 2025-07-08 14:57:10.456 UTC > LOG:  invalid record length at 1F=
B9/C054DF8: wanted 24, got 0
> > < 2025-07-08 14:57:10.456 UTC      00000 2025-07-08 14:57:09 UTC 1098 6=
86d31c5.44a 2025-07-08 14:57:10.456 UTC > LOG:  redo done at 1FB9/C054DC0 s=
ystem usage: CPU: user: 0.00 s, system: 0.00 s, elapsed: 0.00 s
> > < 2025-07-08 14:57:10.475 UTC      00000 2025-07-08 14:57:09 UTC 1099 6=
86d31c5.44b 2025-07-08 14:57:10.475 UTC > LOG:  checkpoint starting: end-of=
-recovery immediate wait
> > < 2025-07-08 14:57:10.501 UTC      00000 2025-07-08 14:57:09 UTC 1099 6=
86d31c5.44b 2025-07-08 14:57:10.501 UTC > LOG:  checkpoint complete: wrote =
86 buffers (0.0%); 0 WAL file(s) added, 0 removed, 2 recycled; write=3D0.01=
0 s, sync=3D0.007 s, total=3D0.028 s; sync files=3D18, longest=3D0.003 s, a=
verage=3D0.001 s; distance=3D339 kB, estimate=3D339 kB
> > < 2025-07-08 14:57:10.510 UTC      00000 2025-07-08 14:55:38 UTC 923 68=
6d316a.39b 2025-07-08 14:57:10.510 UTC > LOG:  database system is ready to =
accept connections
> >
> >
> >  psql -U postgres -h postgres -c "SELECT pg_create_logical_replication_=
slot('support7561_repslot', 'test_decoding');"
> >  pg_create_logical_replication_slot
> > ------------------------------------
> >  (support7561_repslot,1FB9/C081668)
> > (1 row)
> >
> > postgres@support7560_postgres:/var/lib/postgresql/15/main$ psql -U post=
gres -h postgres -c "SELECT slot_name, plugin, slot_type, database, active,=
 restart_lsn, confirmed_flush_lsn FROM pg_replication_slots;"
> >       slot_name      |    plugin     | slot_type | database | active | =
restart_lsn  | confirmed_flush_lsn
> > ---------------------+---------------+-----------+----------+--------+-=
-------------+---------------------
> >  support7561_repslot | test_decoding | logical   | postgres | f      | =
1FB9/C081630 | 1FB9/C081668
> >
> >
> > SHOW shared_buffers;
> >  shared_buffers
> > ----------------
> >  1532512kB
> > (1 row)
> >
> > postgres=3D# \! uname -a
> > Linux support7560_postgres 6.8.0-1030-gcp #32~22.04.1-Ubuntu SMP Tue Ap=
r 29 23:17:09 UTC 2025 x86_64 x86_64 x86_64 GNU/Linux
> >
> > psql -U postgres -h postgres -c "select version()"
> >                                                                version
> > -----------------------------------------------------------------------=
--------------------------------------------------------------
> >  PostgreSQL 15.13 (Ubuntu 15.13-1.pgdg24.04+1) on x86_64-pc-linux-gnu, =
compiled by gcc (Ubuntu 13.3.0-6ubuntu2~24.04) 13.3.0, 64-bit
>
> Hi Abrahim,
>
> Can you also share the stack trace for the crash?
> Also can you share the exact steps used to reproduce the issue?
>

Also, I was going to the logs on found:
> > < 2025-07-08 14:57:08.653 UTC psql postgres postgres 172.18.0.94(53414)=
 SELECT 00000 2025-07-08 14:57:07 UTC 1096 686d31c3.448 2025-07-08 14:57:08=
.653 UTC > LOG:  Initializing CDC decoder

This log is not present in Postgres source code. Why is this log appearing =
here?
Also I would suggest you to post this issue in pgsql-hackers mailing list [=
1].

[1]: pgsql-hackers@lists.postgresql.org

Thanks and Regards,
Shlok Kyal