SHOW

SHOW — show the value of a run-time parameter

Synopsis

SHOW name
SHOW ALL
SHOW name%
SHOW %name
SHOW %name%

Description

SHOW will display the current setting of run-time parameters. These variables can be set using the SET statement, by editing the lightdb.conf configuration file, through the LTOPTIONS environmental variable (when using libpq or a libpq-based application), or through command-line flags when starting the lightdb server. See Chapter 17 for details.

Parameters

name

The name of a run-time parameter. Available parameters are documented in Chapter 17 and on the SET reference page. In addition, there are a few parameters that can be shown but not set:

SERVER_VERSION

Shows the server's version number.

LIGHTDB_SERVER_VERSION

Shows the LightDB server's version number.

LIGHTDB_SERVER_VERSION_NUM

Shows the LightDB server's version number, value is major_version * 10000 + minor_version * 100.

SERVER_ENCODING

Shows the server-side character set encoding. At present, this parameter can be shown but not set, because the encoding is determined at database creation time.

LC_COLLATE

Shows the database's locale setting for collation (text ordering). At present, this parameter can be shown but not set, because the setting is determined at database creation time.

LC_CTYPE

Shows the database's locale setting for character classification. At present, this parameter can be shown but not set, because the setting is determined at database creation time.

IS_SUPERUSER

True if the current role has superuser privileges.

ALL

Show the values of all configuration parameters, with descriptions.

name%

Show the values of all configuration parameters beginning with name, with descriptions.

%name

Show the values of all configuration parameters ending with name, with descriptions.

%name%

Show the values of all configuration parameters including with name, with descriptions.

Notes

The function current_setting produces equivalent output; see Section 9.27.1. Also, the pg_settings system view produces the same information.

Examples

Show the current setting of the parameter DateStyle:

SHOW DateStyle;
 DateStyle
-----------
 ISO, MDY
(1 row)

Show lightdb server version:

SHOW lightdb_server_version;
 lightdb_server_version 
------------------------
 13.8-24.2
(1 row)

Show lightdb server version number:

SHOW lightdb_server_version_num;
 lightdb_server_version_num 
----------------------------
 220400
(1 row)

Show all settings:

SHOW ALL;
            name         | setting |                description                                                          
-------------------------+---------+-------------------------------------------------
 allow_system_table_mods | off     | Allows modifications of the structure of ...
    .
    .
    .
 xmloption               | content | Sets whether XML data in implicit parsing ...
 zero_damaged_pages      | off     | Continues processing past damaged page headers.
(196 rows)

Show all settings beginning with the parameter WAL%:

SHOW WAL%;
             name              |  setting  |                                                description                                                 
-------------------------------+-----------+------------------------------------------------------------------------------------------------------------
 wal_block_size                | 8192      | Shows the block size in the write ahead log.
    .
    .
    .
 wal_writer_flush_after        | 1MB       | Amount of WAL written out by WAL writer that triggers a flush.
(19 rows)

Show all settings ending with the parameter %LEVEL:

SHOW %LEVEL;
               name               | setting |                        description                        
----------------------------------+---------+-----------------------------------------------------------
 auto_explain.log_level           | log     | Log level for the plan.
    .
    .
    .
 wal_level                        | replica | Set the level of information written to the WAL.
(7 rows)

Show all settings including with the parameter %_FREEZE_:

SHOW %_FREEZE_%;
                name                 |  setting  |                                  description                                  
-------------------------------------+-----------+-------------------------------------------------------------------------------
 autovacuum_freeze_max_age           | 200000000 | Age at which to autovacuum a table to prevent transaction ID wraparound.
    .
    .
    .
 vacuum_multixact_freeze_table_age   | 150000000 | Multixact age at which VACUUM should scan whole table to freeze tuples.
(6 rows)

Compatibility

The SHOW command is a LightDB extension.

See Also

SET, RESET