NAME
SET ROLE - set the current user identifier of the current session
SYNOPSIS
SET [ SESSION | LOCAL ] ROLE rolename
SET [ SESSION | LOCAL ] ROLE NONE
RESET ROLE
DESCRIPTION
This command sets the current user identifier of the current SQL
session to be rolename. 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 rolename 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
[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 INHERITS 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 NOINHERITS
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)]