Re: Interpreting shared_buffers setting

Thank you Andrew and Thomas. All is now clear :-)

On Tue, 29 Jan 2019 at 13:07, Andrew Gierth <andrew(at)tao11(dot)riddles(dot)org(dot)uk> wrote:
>
> >>>>> "Bob" == Bob Jolliffe <bobjolliffe(at)gmail(dot)com> writes:
>
> Bob> Excuse me if this is a silly question. I am trying to fiddle with
> Bob> shared_buffers setting on postgresql 10.6 on ubuntu 18.04 server.
>
> Bob> I have this at bottom of my config file:
> Bob> shared_buffers = 1GB
>
> Bob> Yet when I check the setting from pg_setting I see something quite
> Bob> different:
>
> Bob> postgres=# SELECT name, setting FROM pg_settings where name = 'shared_buffers';
> Bob> name | setting
> Bob> ----------------+---------
> Bob> shared_buffers | 131072
>
> pg_settings can tell you more than you asked for:
>
> postgres=# select * from pg_settings where name='shared_buffers';
> -[ RECORD 1 ]---+-------------------------------------------------------------
> name | shared_buffers
> setting | 16384
> unit | 8kB
> category | Resource Usage / Memory
> short_desc | Sets the number of shared memory buffers used by the server.
> extra_desc |
> context | postmaster
> vartype | integer
> source | configuration file
> min_val | 16
> max_val | 1073741823
> enumvals |
> boot_val | 1024
> reset_val | 16384
> sourcefile | /home/andrew/work/pgsql/inst/9.5/data/postgresql.conf
> sourceline | 113
> pending_restart | f
>
> notice that "unit 8kB" line; the displayed integer value is in units of
> 8kB (which is the block size your server was compiled with, which you
> can also see as the block_size parameter).
>
> --
> Andrew (irc:RhodiumToad)