Re: Starting a PostgreSQL server on a dynamic port (parameter port=0)

Kirill Reshke <reshkekirill@gmail.com>

From: Kirill Reshke <reshkekirill@gmail.com>
To: a.mitrokhin@postgrespro.ru
Cc: pgsql-bugs@lists.postgresql.org
Date: 2025-07-10T07:46:55Z
Lists: pgsql-bugs
On Thu, 10 Jul 2025 at 12:15, <a.mitrokhin@postgrespro.ru> wrote:
>
> Hello.
>
>
> Postgres does not allow starting the server with port=0, which prevents
> it from obtaining an arbitrary free port from the kernel.
>
>
> ~$ LANG=C pg_ctl -D data -o "-c port=0" start
> 2025-07-10 05:27:02.785 GMT [702503] FATAL:  0 is outside the valid
> range for parameter "port" (1 .. 65535)
>
>
> This makes it unreliable to start the server in my tests without the
> risk of port conflicts with already running programs, unless resorting
> to an unreliable and race-condition-prone procedure of reserving ports
> in advance.
>
>
> Could you please fix this?


Regression tests somehow solve this problem without any patch, so why
this should be fixed?

-- 
Best regards,
Kirill Reshke