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

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 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))