Sets the current role identifier of the current session.
SET [SESSION | LOCAL] ROLE <rolename>
SET [SESSION | LOCAL] ROLE NONE
RESET ROLE
This command sets the current role identifier of the current SQL-session context to be rolename. The role name may 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 NONE
and RESET
forms reset the current role identifier to be the current session role identifier. These forms may be executed by any user.
COMMIT
or
ROLLBACK
, the session-level setting takes effect again. Note that
SET LOCAL
will appear to have no effect if it is executed outside of a transaction.
Using this command, it is possible to either add privileges or restrict 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, they lose their superuser privileges.
SET ROLE
has effects comparable to SET SESSION AUTHORIZATION
, 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
.
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
Greenplum Database 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; Greenplum Database does not make this restriction. The SESSION
and LOCAL
modifiers are a Greenplum Database extension, as is the RESET
syntax.
Parent topic: SQL Command Reference