Re: Show <parameter> in psql does any calculations?

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.

--
Guillaume
http://blog.guillaume.lelarge.info
http://www.dalibo.com
PostgreSQL Sessions #3: http://www.postgresql-sessions.org