BUG #19391: pg_ctl: the PID file "/xxxx/postmaster.pid" is empty

On Fri, Jan 30, 2026, at 12:59 PM, PG Bug reporting form wrote:

My test framework uses "pg_ctl status ..." to detect a state of Postgres
instance - uninitialized, stopped, running.

Time from time, it returns the error - pg_ctl: the PID file
"/xxxx/postmaster.pid" is empty

You didn't provide enough information. Linux distro and version?

https://github.com/postgrespro/testgres/issues/329

I would say that the operating system is the one that is probably removing the
postmaster.pid. You are using /tmp as your base directory. Service like
systemd-tmpfiles-clean removes temporary files from /tmp. If systemd is not in
use, I would check the cron.

--
Euler Taveira
EDB https://www.enterprisedb.com/

Hello,

Time from time, it returns the error - pg_ctl: the PID file

"/xxxx/postmaster.pid" is empty

I would say that the operating system is the one that is probably removing
the
postmaster.pid. You are using /tmp as your base directory. Service like
systemd-tmpfiles-clean removes temporary files from /tmp. If systemd is
not in
use, I would check the cron.

Base docker images were:
- docker.io/library/alt:p10 (it is altlinux 10)
- docker.io/library/postgres:17-alpine (alpine linux)

Thanks&Regards,
Dmitry Kovalenko.

PG Bug reporting form <noreply@postgresql.org> writes:

My test framework uses "pg_ctl status ..." to detect a state of Postgres
instance - uninitialized, stopped, running.
Time from time, it returns the error - pg_ctl: the PID file
"/xxxx/postmaster.pid" is empty

If you're issuing "pg_ctl status" while a postmaster is starting, it's
possible that you're hitting the tiny window where CreateLockFile()
has opened the file but not yet written anything into it.

We could imagine making pg_ctl not treat this as an error, but
I'm hesitant to do so because of possibly creating race conditions
for the pg_ctl start/stop cases. (Well, it's inherently a race
situation if you issue two concurrent starts ... what I mean is
that failing is the safest option in that scenario.) Depending
on what you intend to do with the pg_ctl status result, acting
as if this isn't an error case could be risky there too.
Given an empty file, we can't distinguish "a postmaster is in
progress of starting" from "a postmaster died while starting",
since no PID is available to test.

regards, tom lane

Hello,

Hope, I was able to fix this problem on a level of my code.

When I get an error "the PID file "/xxxx/postmaster.pid" is empty" I try
to find postmaster process.

If it exists, I sleep few seconds and try to call pg_ctl again.

I am using ps + grep to find this process.

I think, it will be really useful to get this PID from "pg_ctl start"
output instead this combination. If it possible, of course.

Thanks&Regards,

Dmitry Kovalenko

31.01.2026 4:52, Tom Lane пишет: