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Suddenly my postgresql service started crashing for some reason. I wanted to generate coredump file but file is not generating.
I set: "ulimit -S -c unlimited", also added line "*soft core unlimited" to /etc/security/limits.conf.

Also set my destination dir to kernel.core_pattern="/coredumps/core-%e-%s-%u-%g-%p-%t". Also executed "chmod 777" to destination path to eliminate permission issues. I was able to generate test coredump file by executing "perl -MPOSIX -e '$0="ttt"; pause' &" and then running "kill -ABRT " and file got saved to /coredumps with correct filename.

When my postgres crashes i can see in logs:

Resource limits disable core dumping for process 3607766 (postmaster).

Process 3607766 (postmaster) of user 26 dumped core.

[email protected]: Succeeded.

Also i noticed difference between outputs of "cat /proc/pid/limits" between my test process and postgres. Test process has "Max core file size" set to "unlimited" and postgresql value "0" enter image description here

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    Have you tried adding LimitCORE=infinity to the [service] section of the postgress unit file? Commented Oct 11, 2024 at 13:12

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Limits are not system-wide – they are per-process, initialized and inherited similar to environment variables. Your ulimit command therefore only raises the coredump limit for the Bash instance you're entering that command in – not for anyone else and not for any service.

The limits are initialized from /etc/security/limits.conf for user logins; however, on Linux, services don't go through the "user login" procedure even if they have a service account, so the limit initialization from /etc/security will not occur.

Instead all such limits need to be set through the service manager which starts Postgres – in this case systemd, so you need to use systemctl edit to add the LimitCORE= option to the .service file.

Alternatively, you can use the prlimit command to change the resource limits of an already running process, assuming it can still run for a short while before it crashes.

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