query to find out memory values of postgresql memory:

 query the list of parameter

select name,setting from pg_settings;

query the list of parameter requires restart

select name,setting from pg_settings where context='postmaster';

show command used to display the vaule of parameter

query to find out memory values of postgresql memory:

select name,setting from pg_settings where name LIKE '%shared_buffer%';

      name      | setting

----------------+---------

 shared_buffers | 16384

postgres=# show shared_buffers;

 shared_buffers

----------------

 128MB

(1 row)