pg_settings 是一个 系统目录 视图，用于显示当前会话的 配置设置；此外，它还可以被更新，使其在功能上等同于一个会话本地的 SET 命令。
pg_settings 是在 PostgreSQL 7.3 中添加的。
按 PostgreSQL 版本定义
pg_settings (PostgreSQL 19)
View "pg_catalog.pg_settings"
Column | Type | Collation | Nullable | Default
-----------------+---------+-----------+----------+---------
name | text | | |
setting | text | | |
unit | text | | |
category | text | | |
short_desc | text | | |
extra_desc | text | | |
context | text | | |
vartype | text | | |
source | text | | |
min_val | text | | |
max_val | text | | |
enumvals | text[] | | |
boot_val | text | | |
reset_val | text | | |
sourcefile | text | | |
sourceline | integer | | |
pending_restart | boolean | | |
文档: pg_settings
pg_settings (PostgreSQL 18)
View "pg_catalog.pg_settings"
Column | Type | Collation | Nullable | Default
-----------------+---------+-----------+----------+---------
name | text | | |
setting | text | | |
unit | text | | |
category | text | | |
short_desc | text | | |
extra_desc | text | | |
context | text | | |
vartype | text | | |
source | text | | |
min_val | text | | |
max_val | text | | |
enumvals | text[] | | |
boot_val | text | | |
reset_val | text | | |
sourcefile | text | | |
sourceline | integer | | |
pending_restart | boolean | | |
文档: pg_settings
pg_settings (PostgreSQL 17)
View "pg_catalog.pg_settings"
Column | Type | Collation | Nullable | Default
-----------------+---------+-----------+----------+---------
name | text | | |
setting | text | | |
unit | text | | |
category | text | | |
short_desc | text | | |
extra_desc | text | | |
context | text | | |
vartype | text | | |
source | text | | |
min_val | text | | |
max_val | text | | |
enumvals | text[] | | |
boot_val | text | | |
reset_val | text | | |
sourcefile | text | | |
sourceline | integer | | |
pending_restart | boolean | | |
文档: pg_settings
pg_settings (PostgreSQL 16)
View "pg_catalog.pg_settings"
Column | Type | Collation | Nullable | Default
-----------------+---------+-----------+----------+---------
name | text | | |
setting | text | | |
unit | text | | |
category | text | | |
short_desc | text | | |
extra_desc | text | | |
context | text | | |
vartype | text | | |
source | text | | |
min_val | text | | |
max_val | text | | |
enumvals | text[] | | |
boot_val | text | | |
reset_val | text | | |
sourcefile | text | | |
sourceline | integer | | |
pending_restart | boolean | | |
文档: pg_settings
pg_settings (PostgreSQL 15)
View "pg_catalog.pg_settings"
Column | Type | Collation | Nullable | Default
-----------------+---------+-----------+----------+---------
name | text | | |
setting | text | | |
unit | text | | |
category | text | | |
short_desc | text | | |
extra_desc | text | | |
context | text | | |
vartype | text | | |
source | text | | |
min_val | text | | |
max_val | text | | |
enumvals | text[] | | |
boot_val | text | | |
reset_val | text | | |
sourcefile | text | | |
sourceline | integer | | |
pending_restart | boolean | | |
文档: pg_settings
pg_settings (PostgreSQL 14)
View "pg_catalog.pg_settings"
Column | Type | Collation | Nullable | Default
-----------------+---------+-----------+----------+---------
name | text | | |
setting | text | | |
unit | text | | |
category | text | | |
short_desc | text | | |
extra_desc | text | | |
context | text | | |
vartype | text | | |
source | text | | |
min_val | text | | |
max_val | text | | |
enumvals | text[] | | |
boot_val | text | | |
reset_val | text | | |
sourcefile | text | | |
sourceline | integer | | |
pending_restart | boolean | | |
文档: pg_settings
pg_settings (PostgreSQL 13)
View "pg_catalog.pg_settings"
Column | Type | Collation | Nullable | Default
-----------------+---------+-----------+----------+---------
name | text | | |
setting | text | | |
unit | text | | |
category | text | | |
short_desc | text | | |
extra_desc | text | | |
context | text | | |
vartype | text | | |
source | text | | |
min_val | text | | |
max_val | text | | |
enumvals | text[] | | |
boot_val | text | | |
reset_val | text | | |
sourcefile | text | | |
sourceline | integer | | |
pending_restart | boolean | | |
文档: pg_settings
pg_settings (PostgreSQL 12)
View "pg_catalog.pg_settings"
Column | Type | Collation | Nullable | Default
-----------------+---------+-----------+----------+---------
name | text | | |
setting | text | | |
unit | text | | |
category | text | | |
short_desc | text | | |
extra_desc | text | | |
context | text | | |
vartype | text | | |
source | text | | |
min_val | text | | |
max_val | text | | |
enumvals | text[] | | |
boot_val | text | | |
reset_val | text | | |
sourcefile | text | | |
sourceline | integer | | |
pending_restart | boolean | | |
文档: pg_settings
pg_settings (PostgreSQL 11)
View "pg_catalog.pg_settings"
Column | Type | Collation | Nullable | Default
-----------------+---------+-----------+----------+---------
name | text | | |
setting | text | | |
unit | text | | |
category | text | | |
short_desc | text | | |
extra_desc | text | | |
context | text | | |
vartype | text | | |
source | text | | |
min_val | text | | |
max_val | text | | |
enumvals | text[] | | |
boot_val | text | | |
reset_val | text | | |
sourcefile | text | | |
sourceline | integer | | |
pending_restart | boolean | | |
文档: pg_settings
pg_settings (PostgreSQL 10)
View "pg_catalog.pg_settings"
Column | Type | Collation | Nullable | Default
-----------------+---------+-----------+----------+---------
name | text | | |
setting | text | | |
unit | text | | |
category | text | | |
short_desc | text | | |
extra_desc | text | | |
context | text | | |
vartype | text | | |
source | text | | |
min_val | text | | |
max_val | text | | |
enumvals | text[] | | |
boot_val | text | | |
reset_val | text | | |
sourcefile | text | | |
sourceline | integer | | |
pending_restart | boolean | | |
文档: pg_settings
pg_settings (PostgreSQL 9.6)
View "pg_catalog.pg_settings"
Column | Type | Modifiers
-----------------+---------+-----------
name | text |
setting | text |
unit | text |
category | text |
short_desc | text |
extra_desc | text |
context | text |
vartype | text |
source | text |
min_val | text |
max_val | text |
enumvals | text[] |
boot_val | text |
reset_val | text |
sourcefile | text |
sourceline | integer |
pending_restart | boolean |
文档: pg_settings
pg_settings (PostgreSQL 9.5)
View "pg_catalog.pg_settings"
Column | Type | Modifiers
-----------------+---------+-----------
name | text |
setting | text |
unit | text |
category | text |
short_desc | text |
extra_desc | text |
context | text |
vartype | text |
source | text |
min_val | text |
max_val | text |
enumvals | text[] |
boot_val | text |
reset_val | text |
sourcefile | text |
sourceline | integer |
pending_restart | boolean |
文档: pg_settings
pg_settings (PostgreSQL 9.4)
View "pg_catalog.pg_settings"
Column | Type | Modifiers
------------+---------+-----------
name | text |
setting | text |
unit | text |
category | text |
short_desc | text |
extra_desc | text |
context | text |
vartype | text |
source | text |
min_val | text |
max_val | text |
enumvals | text[] |
boot_val | text |
reset_val | text |
sourcefile | text |
sourceline | integer |
文档: pg_settings
pg_settings (PostgreSQL 9.3)
View "pg_catalog.pg_settings"
Column | Type | Modifiers
------------+---------+-----------
name | text |
setting | text |
unit | text |
category | text |
short_desc | text |
extra_desc | text |
context | text |
vartype | text |
source | text |
min_val | text |
max_val | text |
enumvals | text[] |
boot_val | text |
reset_val | text |
sourcefile | text |
sourceline | integer |
文档: pg_settings
pg_settings (PostgreSQL 9.2)
View "pg_catalog.pg_settings"
Column | Type | Modifiers
------------+---------+-----------
name | text |
setting | text |
unit | text |
category | text |
short_desc | text |
extra_desc | text |
context | text |
vartype | text |
source | text |
min_val | text |
max_val | text |
enumvals | text[] |
boot_val | text |
reset_val | text |
sourcefile | text |
sourceline | integer |
文档: pg_settings
pg_settings (PostgreSQL 9.1)
View "pg_catalog.pg_settings"
Column | Type | Modifiers
------------+---------+-----------
name | text |
setting | text |
unit | text |
category | text |
short_desc | text |
extra_desc | text |
context | text |
vartype | text |
source | text |
min_val | text |
max_val | text |
enumvals | text[] |
boot_val | text |
reset_val | text |
sourcefile | text |
sourceline | integer |
文档: pg_settings
pg_settings (PostgreSQL 9.0)
View "pg_catalog.pg_settings"
Column | Type | Modifiers
------------+---------+-----------
name | text |
setting | text |
unit | text |
category | text |
short_desc | text |
extra_desc | text |
context | text |
vartype | text |
source | text |
min_val | text |
max_val | text |
enumvals | text[] |
boot_val | text |
reset_val | text |
sourcefile | text |
sourceline | integer |
文档: pg_settings
pg_settings (PostgreSQL 8.4)
View "pg_catalog.pg_settings"
Column | Type | Modifiers
------------+---------+-----------
name | text |
setting | text |
unit | text |
category | text |
short_desc | text |
extra_desc | text |
context | text |
vartype | text |
source | text |
min_val | text |
max_val | text |
enumvals | text[] |
boot_val | text |
reset_val | text |
sourcefile | text |
sourceline | integer |
View definition:
SELECT a.name, a.setting, a.unit, a.category, a.short_desc, a.extra_desc, a.context, a.vartype, a.source, a.min_val, a.max_val, a.enumvals, a.boot_val, a.reset_val, a.sourcefile, a.sourceline
FROM pg_show_all_settings() a(name, setting, unit, category, short_desc, extra_desc, context, vartype, source, min_val, max_val, enumvals, boot_val, reset_val, sourcefile, sourceline);
Rules:
pg_settings_n AS
ON UPDATE TO pg_settings DO INSTEAD NOTHING
pg_settings_u AS
ON UPDATE TO pg_settings
WHERE new.name = old.name DO SELECT set_config(old.name, new.setting, false) AS set_config
文档: pg_settings
pg_settings (PostgreSQL 8.3)
View "pg_catalog.pg_settings"
Column | Type | Modifiers
------------+------+-----------
name | text |
setting | text |
unit | text |
category | text |
short_desc | text |
extra_desc | text |
context | text |
vartype | text |
source | text |
min_val | text |
max_val | text |
View definition:
SELECT a.name, a.setting, a.unit, a.category, a.short_desc, a.extra_desc, a.context, a.vartype, a.source, a.min_val, a.max_val
FROM pg_show_all_settings() a(name text, setting text, unit text, category text, short_desc text, extra_desc text, context text, vartype text, source text, min_val text, max_val text);
Rules:
pg_settings_n AS
ON UPDATE TO pg_settings DO INSTEAD NOTHING
pg_settings_u AS
ON UPDATE TO pg_settings
WHERE new.name = old.name DO SELECT set_config(old.name, new.setting, false) AS set_config
文档: pg_settings
pg_settings (PostgreSQL 8.2)
View "pg_catalog.pg_settings"
Column | Type | Modifiers
------------+------+-----------
name | text |
setting | text |
unit | text |
category | text |
short_desc | text |
extra_desc | text |
context | text |
vartype | text |
source | text |
min_val | text |
max_val | text |
View definition:
SELECT a.name, a.setting, a.unit, a.category, a.short_desc, a.extra_desc, a.context, a.vartype, a.source, a.min_val, a.max_val
FROM pg_show_all_settings() a(name text, setting text, unit text, category text, short_desc text, extra_desc text, context text, vartype text, source text, min_val text, max_val text);
Rules:
pg_settings_n AS
ON UPDATE TO pg_settings DO INSTEAD NOTHING
pg_settings_u AS
ON UPDATE TO pg_settings
WHERE new.name = old.name DO SELECT set_config(old.name, new.setting, false) AS set_config
文档: pg_settings
变更历史
- PostgreSQL 9.5
- 添加了列
pending_restart(提交 a486e357)
- 添加了列
- PostgreSQL 8.4
- PostgreSQL 8.2
- 添加了列
unit(提交 b517e653)
- 添加了列
- PostgreSQL 8.0
- 添加了以下列 (提交 66989aa2)
类别简短描述扩展描述
- 添加了以下列 (提交 66989aa2)
- PostgreSQL 7.3
- 添加 (提交 45e25445)
pg_settings 最初通过 contrib 模块 tablefunc 以函数 show_all_settings() 的形式提供。
源代码
pg_settings 源自内部函数 pg_show_all_settings() (src/backend/catalog/system_views.sql)
CREATE VIEW pg_settings AS
SELECT * FROM pg_show_all_settings() AS A;
CREATE RULE pg_settings_u AS
ON UPDATE TO pg_settings
WHERE new.name = old.name DO
SELECT set_config(old.name, new.setting, 'f');
CREATE RULE pg_settings_n AS
ON UPDATE TO pg_settings
DO INSTEAD NOTHING;
GRANT SELECT, UPDATE ON pg_settings TO PUBLIC;
示例
针对 port 参数的 pg_settings 记录
postgres=# SELECT * FROM pg_settings WHERE name = 'port'; -[ RECORD 1 ]---+----------------------------------------------------- name | port setting | 5433 unit | category | Connections and Authentication / Connection Settings short_desc | Sets the TCP port the server listens on. extra_desc | context | postmaster vartype | integer source | configuration file min_val | 1 max_val | 65535 enumvals | boot_val | 5432 reset_val | 5433 sourcefile | /var/lib/pgsql/postgresql.local.conf sourceline | 3 pending_restart | f
针对 log_statement 参数的 pg_settings 记录，该参数已在当前会话中被修改
postgres=# SET log_statement TO mod;
SET
postgres=# SELECT * FROM pg_settings WHERE name = 'log_statement';
-[ RECORD 1 ]---+------------------------------------
name | log_statement
setting | mod
unit |
category | Reporting and Logging / What to Log
short_desc | Sets the type of statements logged.
extra_desc |
context | superuser
vartype | enum
source | session
min_val |
max_val |
enumvals | {none,ddl,mod,all}
boot_val | none
reset_val | none
sourcefile |
sourceline |
pending_restart | f
直接更新 pg_settings 视图
postgres=# UPDATE pg_settings SET setting = 'all' WHERE name = 'log_statement'; set_config ------------ all (1 row) UPDATE 0
尝试更新一个无法修改的设置
postgres=# UPDATE pg_settings SET setting = '9999' WHERE name = 'port'; ERROR: parameter "port" cannot be changed without restarting the server
参考资料
- PostgreSQL 文档: pg_settings
反馈
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