Re: Mac OS X shared_buffers not same as postgresql.conf file

On Sun, 2011-09-25 at 12:13 -0500, Neil Tiffin wrote:
> On Sep 24, 2011, at 4:21 PM, Guillaume Lelarge wrote:
>
> > On Sat, 2011-09-24 at 14:43 -0500, Neil Tiffin wrote:
> >> On Sep 24, 2011, at 1:31 PM, Joe Conway wrote:
> >>
> >>> On 09/23/2011 02:33 PM, Neil Tiffin wrote:
> >>>> I have shared_buffers in the config file set for 32 MB and pgAdmin
> >>>> reports a value of 32 MB, but pgAdmin also says the current value is
> >>>> 4096. Can anyone point me to any docs about why the current value
> >>>> may be different than the config value? Temp_buffers are the same
> >>>> way, config file 8MB, but current value in pgAdmin is 1024?
> >>>
> >>> Internally shared_buffers is tracked as number of 8K pages.
> >>>
> >>> postgres=# show shared_buffers;
> >>> shared_buffers
> >>> ----------------
> >>> 32MB
> >>> (1 row)
> >>>
> >>> postgres=# select setting from pg_settings where name='shared_buffers';
> >>> setting
> >>> ---------
> >>> 4096
> >>> (1 row)
> >>>
> >>> postgres=# select 4096 * 8 / 1024 as MB;
> >>> mb
> >>> ----
> >>> 32
> >>> (1 row)
> >>>
> >>> HTH,
> >>
> >> Excellent, just what I was looking for. I know there had to be a simple explanation, even though it seems a little retarded that pgAdmin does not point this out.
> >
> > And how do you get that value from pgAdmin? the config editor gives me
> > the value with its unit, so I guess it's not from the config editor.
> >
>
> I got the values from selecting in pgAdmin: Tools -> Server Configuration -> postgresql.conf, then I get a table with setting name, value, current value, and comment columns. The 'value' column shows the unit, but the 'current value' column does not, at least on Mac OS X.
>

Yes, I have the same behaviour. The "Value" comes from the file (hence
with the unit), and the "Current Value" comes from PostgreSQL (simple
query: select setting from pg_settings where name='shared_buffers').

--
Guillaume
http://blog.guillaume.lelarge.info
http://www.dalibo.com