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))