Provided by: postgresql-client-9.1_9.1.1-1_i386 bug

NAME

       SET_SESSION_AUTHORIZATION - set the session user identifier and the
       current user identifier of the current session

SYNOPSIS

       SET [ SESSION | LOCAL ] SESSION AUTHORIZATION user_name
       SET [ SESSION | LOCAL ] SESSION AUTHORIZATION DEFAULT
       RESET SESSION AUTHORIZATION

DESCRIPTION

       This command sets the session user identifier and the current user
       identifier of the current SQL session to be user_name. The user name
       can be written as either an identifier or a string literal. Using this
       command, it is possible, for example, to temporarily become an
       unprivileged user and later switch back to being a superuser.

       The session user identifier is initially set to be the (possibly
       authenticated) user name provided by the client. The current user
       identifier is normally equal to the session user identifier, but might
       change temporarily in the context of SECURITY DEFINER functions and
       similar mechanisms; it can also be changed by SET ROLE (SET_ROLE(7)).
       The current user identifier is relevant for permission checking.

       The session user identifier can be changed only if the initial session
       user (the authenticated user) had the superuser privilege. Otherwise,
       the command is accepted only if it specifies the authenticated user
       name.

       The SESSION and LOCAL modifiers act the same as for the regular SET(7)
       command.

       The DEFAULT and RESET forms reset the session and current user
       identifiers to be the originally authenticated user name. These forms
       can be executed by any user.

NOTES

       SET SESSION AUTHORIZATION cannot be used within a SECURITY DEFINER
       function.

EXAMPLES

           SELECT SESSION_USER, CURRENT_USER;

            session_user | current_user
           --------------+--------------
            peter        | peter

           SET SESSION AUTHORIZATION 'paul';

           SELECT SESSION_USER, CURRENT_USER;

            session_user | current_user
           --------------+--------------
            paul         | paul

COMPATIBILITY

       The SQL standard allows some other expressions to appear in place of
       the literal user_name, but these options are not important in practice.
       PostgreSQL allows identifier syntax ("username"), which SQL does not.
       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.

       The privileges necessary to execute this command are left
       implementation-defined by the standard.

SEE ALSO

       SET ROLE (SET_ROLE(7))