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.
RESET forms reset the current role identifier to be the current session role identifier. These forms may be run by any user.
ROLLBACK, the session-level setting takes effect again. Note that
SET LOCALwill appear to have no effect if it is run 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
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 does not process session variables specified by the role's
ALTER ROLE settings; the session variables are only processed during login.
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
LOCAL modifiers are a Greenplum Database extension, as is the
Parent topic: SQL Commands