Provided by: postgresql-client-8.4_8.4.11-1_amd64 bug

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)]