Re: Show in psql does any calculations? - Mailing list pgsql-general

On Tue, 2011-12-27 at 14:56 +0530, Raghavendra wrote:
> Respected,
>
> Am in PG 9.1. See below ouputs.
>

> *By query:*

> postgres=# SELECT name, setting, unit,context FROM pg_settings WHERE
> category like '%Resource Usage / Memory%' ORDER BY name;
>            name            | setting | unit |  context
> ---------------------------+---------+------+------------
>  maintenance_work_mem      | 16384   | kB   | user
>  max_prepared_transactions  | 0          |       | postmaster
>  max_stack_depth                 | 2048    | kB   | superuser
>  shared_buffers                     | 4096    | 8kB  | postmaster
>  temp_buffers                       | 1024    | 8kB  | user
>  track_activity_query_size     | 1024    |      | postmaster
>  work_mem                          | 2048    | kB   | user
> (7 rows)
>

> *By session command:*

> postgres=# show work_mem ;
>  work_mem
> ----------
>  2MB
> (1 row)
>
> postgres=# show shared_buffers ;
>  shared_buffers
> ----------------
>  32MB
> (1 row)
>
> By the query, its clear that "setting" value is multiplied with unit to get
> the sesssion level command value which is displayed here. However, I am
> trying to get the query of it which is executed at session-level with SHOW
> command. I tried "psql -E" option tooo..
>
> -bash-3.2$ psql -E
> psql.bin (9.1.0)
> Type "help" for help.
>
> postgres=# show work_mem ;
>  work_mem
> ----------
>  2MB
> (1 row)
>
> Why the query is not displayed with -E option ?
> Am I missing something here, please help me in clarifying it.
>

-E works only for meta-commands, ie commands which start with \

Moreover, SHOW is an actual SQL command. So I'm not sure what you're
trying to find with the -E command line switch.