allow_alter_system

When allow_alter_system is set to off, an error is returned if the ALTER SYSTEM command is executed. This parameter can only be set in the postgresql.conf file or on the server command line. The default value is on.

Note that this setting must not be regarded as a security feature. It only disables the ALTER SYSTEM command. It does not prevent a superuser from changing the configuration using other SQL commands. A superuser has many ways of executing shell commands at the operating system level, and can therefore modify postgresql.auto.conf regardless of the value of this setting.

Turning this setting off is intended for environments where the configuration of PostgreSQL is managed by some external tool. In such environments, a well intentioned superuser might mistakenly use ALTER SYSTEM to change the configuration instead of using the external tool. This might result in unintended behavior, such as the external tool overwriting the change at some later point in time when it updates the configuration. Setting this parameter to off can help avoid such mistakes.

This parameter only controls the use of ALTER SYSTEM. The settings stored in postgresql.auto.conf take effect even if allow_alter_system is set to off.