SHOW
SHOW
is a utility command for displaying the current value of a configuration parameter.
SHOW
was added in PostgreSQL 6.1.
Usage
SHOW
is a simple and intuitive way of displaying the current value of a configuration parameter, or of listing the current value of all configuration parameters via the SHOW ALL
syntax.
For historical reasons SHOW
can also display the current setting for the following items:
IS_SUPERUSER
LC_COLLATE
LC_TYPE
SERVER_ENCODING
SERVER_VERSION
Alternatives to the SHOW command
The rows returned by SHOW
cannot be manipulated at the SQL level, which limits the usefulness of this command to ad-hoc command-line queries.
The function current_setting()
and the view pg_settings
provide a more flexible way of obtaining information about current configuration parameter settings.
Source code
The code implementing SHOW
is contained in src/backend/utils/misc/guc.c, specifically functions:
ShowGUCConfigOption()
forSHOW name
ShowAllGUCConfig()
forSHOW ALL
Change history
- PostgreSQL 7.4
- PostgreSQL 7.2
SHOW ALL
syntax added (commit 4ee76ad8)
- PostgreSQL 6.1
- added (initial commit 4b531912)
Examples
Display a normal configuration parameter:
postgres=# SHOW port; port ------ 5432 (1 row)
Attempt to display a non-existent configuration parameter:
postgres=# SHOW foo; ERROR: unrecognized configuration parameter "foo"
Show all configuration parameters (output truncated for clarity):
postgres=# SHOW ALL; -[ RECORD 1 ]----------------------------------------------------------------------- name | allow_system_table_mods setting | off description | Allows modifications of the structure of system tables. -[ RECORD 2 ]----------------------------------------------------------------------- name | application_name setting | psql description | Sets the application name to be reported in statistics and logs. -[ RECORD 3 ]----------------------------------------------------------------------- name | archive_cleanup_command setting | description | Sets the shell command that will be executed at every restart point. -[ RECORD 4 ]----------------------------------------------------------------------- ...
References
- PostgreSQL documentation: SHOW