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))