Postgresql 中文操作指南
Description
SHOW 将显示运行时参数的当前设置。可以使用 SET 语句、通过编辑 postgresql.conf 配置文件、通过 PGOPTIONS 环境变量（使用 libpq 或基于 libpq 的应用程序时）或在启动 postgres 服务器时通过命令行标记设置这些变量。有关详细信息，请参见 Chapter 20 。
SHOW will display the current setting of run-time parameters. These variables can be set using the SET statement, by editing the postgresql.conf configuration file, through the PGOPTIONS environmental variable (when using libpq or a libpq-based application), or through command-line flags when starting the postgres server. See Chapter 20 for details.
Parameters
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name
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The name of a run-time parameter. Available parameters are documented in Chapter 20 and on the SET reference page. In addition, there are a few parameters that can be shown but not set:
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ALL
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Show the values of all configuration parameters, with descriptions.
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SERVER_VERSION
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Shows the server’s version number.
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SERVER_ENCODING
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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.
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LC_COLLATE
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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.
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LC_CTYPE
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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.
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IS_SUPERUSER
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True if the current role has superuser privileges.
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Notes
函数 current_setting 生成等效的输出；参见 Section 9.27.1 。此外， pg_settings 系统视图生成相同的信息。
The function current_setting produces equivalent output; see Section 9.27.1. Also, the pg_settings system view produces the same information.
Examples
显示参数 DateStyle 的当前设置：
Show the current setting of the parameter DateStyle:
SHOW DateStyle;
DateStyle
-----------
ISO, MDY
(1 row)显示参数 geqo 的当前设置：
Show the current setting of the parameter geqo:
SHOW geqo;
geqo
------
on
(1 row)显示所有设置：
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)