Provided by: postgresql-client-8.4_8.4.11-1_amd64 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 username
       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 username. 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 [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 username,
       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)]