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. Note that SET ROLE and SET SESSION AUTHORIZATION are
       exceptions; permissions checks for those continue to use the current session user and the
       initial session user (the authenticated user), respectively.

       The current session user must have the SET option for the specified role_name, either
       directly or indirectly via a chain of memberships with the SET option. (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 command.

       SET ROLE NONE sets the current user identifier to the current session user identifier, as
       returned by session_user.  RESET ROLE sets the current user identifier to the
       connection-time setting specified by the command-line options, ALTER ROLE, or ALTER
       DATABASE, if any such settings exist. Otherwise, RESET ROLE sets the current user
       identifier to 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 been granted memberships WITH INHERIT TRUE, it automatically
       has all the privileges of every such role. In this case, SET ROLE effectively drops all
       the privileges except for those which the target role directly possesses or inherits. On
       the other hand, if the session user role has been granted memberships WITH INHERIT FALSE,
       the privileges of the granted roles can't be accessed by default. However, if the role was
       granted WITH SET TRUE, the session user can use SET ROLE to drop the privileges assigned
       directly to the session user and instead acquire the privileges available to the named
       role. If the role was granted WITH INHERIT FALSE, SET FALSE then the privileges of that
       role cannot be exercised either with or without SET ROLE.

       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.

       SET ROLE does not process session variables as specified by the role's ALTER ROLE
       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))