On 03/20/2018 11:57 AM, JotaComm wrote:
Hello, Today I found this message in my Postgres log: FATAL: semctl(15073290, 4, SETVAL, 0) failed: Invalid argumentuser=,db=,app=,host= LOG: server process (PID 30741) exited with exit code 1user=,db=,app=,host= LOG: terminating any other active server processes WARNING: terminating connection because of crash of another server processDETAIL: The postmaster has commanded this server process to roll back the current transaction and exit, because another server process exited abnormally and possibly corrupted shared memory. HINT: In a moment you should be able to reconnect to the database and repeat your command.Postgres: PostgreSQL 9.6.3 on x86_64-pc-linux-gnu, compiled by gcc (Ubuntu 5.4.0-6ubuntu1~16.04.4) 5.4.0 20160609, 64-bitLinux: Linux INVST-APP-01A 4.4.0-62-generic #83-Ubuntu SMP Wed Jan 18 14:10:15 UTC 2017 x86_64 x86_64 x86_64 GNU/LinuxFATAL: semctl(15073290, 4, SETVAL, 0) failed: Invalid argumentuser=,db=,app=,host= LOG: server process (PID 30741) exited with exit code 1user=,db=,app=,host= LOG: terminating any other active server processes WARNING: terminating connection because of crash of another server processDETAIL: The postmaster has commanded this server process to roll back the current transaction and exit, because another server process exited abnormally and possibly corrupted shared memory. HINT: In a moment you should be able to reconnect to the database and repeat your command.Any suggestions to discovery about this behavior?
?: https://www.postgresql.org/docs/10/static/kernel-resources.html " 18.4.2. systemd RemoveIPCIf systemd is in use, some care must be taken that IPC resources (shared memory and semaphores) are not prematurely removed by the operating system. This is especially of concern when installing PostgreSQL from source. Users of distribution packages of PostgreSQL are less likely to be affected, as the postgres user is then normally created as a system user.
The setting RemoveIPC in logind.conf controls whether IPC objects are removed when a user fully logs out. System users are exempt. This setting defaults to on in stock systemd, but some operating system distributions default it to off.
A typical observed effect when this setting is on is that the semaphore objects used by a PostgreSQL server are removed at apparently random times, leading to the server crashing with log messages like
LOG: semctl(1234567890, 0, IPC_RMID, ...) failed: Invalid argument
Different types of IPC objects (shared memory vs. semaphores, System V
vs. POSIX) are treated slightly differently by systemd, so one might
observe that some IPC resources are not removed in the same way as
others. But it is not advisable to rely on these subtle differences.
A “user logging out” might happen as part of a maintenance job or manually when an administrator logs in as the postgres user or something similar, so it is hard to prevent in general.
What is a “system user” is determined at systemd compile time from the SYS_UID_MAX setting in /etc/login.defs.
Packaging and deployment scripts should be careful to create the postgres user as a system user by using useradd -r, adduser --system, or equivalent.
Alternatively, if the user account was created incorrectly or cannot be changed, it is recommended to set
RemoveIPC=no in /etc/systemd/logind.conf or another appropriate configuration file. CautionAt least one of these two things has to be ensured, or the PostgreSQL server will be very unreliable.
"
Thanks a lot. Best regards -- JotaComm http://jotacomm.wordpress.com
-- Adrian Klaver adrian.klaver@xxxxxxxxxxx
