SET SESSION AUTHORIZATION(7)
NAME
SET_SESSION_AUTHORIZATION - set the session user identifier and the
current user identifier of the current session
SYNOPSIS
SET [ SESSION | LOCAL ] SESSION AUTHORIZATION user_name
SET [ SESSION | LOCAL ] SESSION AUTHORIZATION DEFAULT
RESET SESSION AUTHORIZATION
DESCRIPTION
This command sets the session user identifier and the current user
identifier of the current SQL session to be user_name. The user name
can be written as either an identifier or a string literal. Using this
command, it is possible, for example, to temporarily become an
unprivileged user and later switch back to being a superuser.
The session user identifier is initially set to be the (possibly
authenticated) user name provided by the client. The current user
identifier is normally equal to the session user identifier, but might
change temporarily in the context of SECURITY DEFINER functions and
similar mechanisms; it can also be changed by SET ROLE (SET_ROLE(7)).
The current user identifier is relevant for permission checking.
The session user identifier can be changed only if the initial session
user (the authenticated user) had the superuser privilege. Otherwise,
the command is accepted only if it specifies the authenticated user
name.
The SESSION and LOCAL modifiers act the same as for the regular SET(7)
command.
The DEFAULT and RESET forms reset the session and current user
identifiers to be the originally authenticated user name. These forms
can be executed by any user.
NOTES
SET SESSION AUTHORIZATION cannot be used within a SECURITY DEFINER
function.
EXAMPLES
SELECT SESSION_USER, CURRENT_USER;
session_user | current_user
--------------+--------------
peter | peter
SET SESSION AUTHORIZATION 'paul';
SELECT SESSION_USER, CURRENT_USER;
session_user | current_user
--------------+--------------
paul | paul
COMPATIBILITY
The SQL standard allows some other expressions to appear in place of
the literal user_name, but these options are not important in practice.
PostgreSQL allows identifier syntax ("username"), which SQL does not.
SQL does not allow this command during a transaction; PostgreSQL does
not make this restriction because there is no reason to. The SESSION
and LOCAL modifiers are a PostgreSQL extension, as is the RESET syntax.
The privileges necessary to execute this command are left
implementation-defined by the standard.
SEE ALSO
SET ROLE (SET_ROLE(7))
PostgreSQL 9.6.6 2017 SET SESSION AUTHORIZATION(7)
PostgreSQL 9.6.6 - Generated Sat Dec 2 13:08:53 CST 2017