Provided by: postgresql-client-9.5_9.5.25-0ubuntu0.16.04.1_amd64 

NAME
SET_ROLE - set the current user identifier of the current session
SYNOPSIS
SET [ SESSION | LOCAL ] ROLE role_name
SET [ SESSION | LOCAL ] ROLE NONE
RESET ROLE
DESCRIPTION
This command sets the current user identifier of the current SQL session to be role_name. The role name
can be written as either an identifier or a string literal. After SET ROLE, permissions checking for SQL
commands is carried out as though the named role were the one that had logged in originally.
The specified role_name must be a role that the current session user is a member of. (If the session user
is a superuser, any role can be selected.)
The SESSION and LOCAL modifiers act the same as for the regular SET(7) command.
The NONE and RESET forms reset the current user identifier to be the current session user identifier.
These forms can be executed by any user.
NOTES
Using this command, it is possible to either add privileges or restrict one's privileges. If the session
user role has the INHERIT attribute, then it automatically has all the privileges of every role that it
could SET ROLE to; in this case SET ROLE effectively drops all the privileges assigned directly to the
session user and to the other roles it is a member of, leaving only the privileges available to the named
role. On the other hand, if the session user role has the NOINHERIT attribute, SET ROLE drops the
privileges assigned directly to the session user and instead acquires the privileges available to the
named role.
In particular, when a superuser chooses to SET ROLE to a non-superuser role, she loses her superuser
privileges.
SET ROLE has effects comparable to SET SESSION AUTHORIZATION (SET_SESSION_AUTHORIZATION(7)), but the
privilege checks involved are quite different. Also, SET SESSION AUTHORIZATION determines which roles are
allowable for later SET ROLE commands, whereas changing roles with SET ROLE does not change the set of
roles allowed to a later SET ROLE.
SET ROLE does not process session variables as specified by the role's ALTER ROLE (ALTER_ROLE(7))
settings; this only happens during login.
SET ROLE cannot be used within a SECURITY DEFINER function.
EXAMPLES
SELECT SESSION_USER, CURRENT_USER;
session_user | current_user
--------------+--------------
peter | peter
SET ROLE 'paul';
SELECT SESSION_USER, CURRENT_USER;
session_user | current_user
--------------+--------------
peter | paul
COMPATIBILITY
PostgreSQL allows identifier syntax ("rolename"), while the SQL standard requires the role name to be
written as a string literal. 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.
SEE ALSO
SET SESSION AUTHORIZATION (SET_SESSION_AUTHORIZATION(7))
PostgreSQL 9.5.25 2021 SET ROLE(7)