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Message-ID: <dcc563d10809221121k2c3eb5dcpb4cbf823b08defc0@mail.gmail.com>
Date: Mon, 22 Sep 2008 12:21:35 -0600
From: "Scott Marlowe" <scott.marlowe@gmail.com>
To: "Tena Sakai" <tsakai@gallo.ucsf.edu>
Subject: Re: question on pg_ctl
Cc: pgsql-admin@postgresql.org
In-Reply-To: <FE44E0D7EAD2ED4BB2165071DB8E328C0378F4F8@egcrc-ex01.egcrc.org>
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References: <FE44E0D7EAD2ED4BB2165071DB8E328C0378F4F8@egcrc-ex01.egcrc.org>

On Mon, Sep 22, 2008 at 11:49 AM, Tena Sakai <tsakai@gallo.ucsf.edu> wrote:
> Hi Everybody,
>
> I want to change a line in postgresql.conf (shared_buffers)
> and then issue a command:
>   pg_ctl reload
>
> This forces the postmaster process to reread the configuration
> file with new shared_buffer value.  And the postgres process
> that comes to life from this point on will execute with the
> newly specified value.  Correct?

To quote the postgresql.conf file:

shared_buffers = 150MB                  # min 128kB or max_connections*16kB
                                        # (change requires restart)

So it requires a complete restart.  Note that for the things you can
reload on, there's no real effect on running queries or connections
(at least no detrimental ones I can think of.)