Re: BUG #19610: Database won't start if an unrelated process is exist

> On 6 Aug 2026, at 14:50, PG Bug reporting form <noreply(at)postgresql(dot)org> wrote:
>
> The following bug has been logged on the website:
>
> Bug reference: 19610
> Logged by: Lev Sch
> Email address: scherbakov_lo_radarmms(at)mail(dot)ru
> PostgreSQL version: 18.4
> Operating system: Ubuntu 18.04.4 LTS
> Description:
>
> pg_ctl: another server might be running; trying to start server anyway
> waiting for server to start....2026-08-06 15:39:08.371 MSK [2102] FATAL:
> lock file "postmaster.pid" already exists
> 2026-08-06 15:39:08.371 MSK [2102] HINT: Is another postmaster (PID 1957)
> running in data directory "/media/firefly/microsdCard/database"?
> stopped waiting
> pg_ctl: could not start server
> Examine the log output.
>
> Steps:
> 1. start Postgress database
> 2. hard reboot system by
> sudo sh -c "echo b > /proc/sysrq-trigger"
> 3. wait for system boot up.
> 4. get a PID-number from the the first line of postmaster.pid
> 5. create ANY process that have PID that same as PID-number
> 6. start Postgress database
> 7. The database will not start
>
> If skip step 5 then database starts successfully.

This is not a bug, it is the intended behaviour, a process with the PID from
the .pid file which is owned by the same userid is reported this way.

--
Daniel Gustafsson