SET ROLE
Description
This command sets the current user identifier of the current SQL session to berole_name. The role name can be written as either an identifier or a string literal. AfterSET ROLE, permissions checking for SQL commands is carried out as though the named role were the one that had logged in originally.
The specifiedrole_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.)
TheSESSION andLOCAL modifiers act the same as for the regularSET command.
TheNONE andRESET 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 theINHERITS attribute, then it automatically has all the privileges of every role that it couldSET ROLE to; in this caseSET 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 theNOINHERITS 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 toSET ROLE to a non-superuser role, she loses her superuser privileges.
SET ROLE has effects comparable toSET SESSION AUTHORIZATION, but the privilege checks involved are quite different. Also,SET SESSION AUTHORIZATION determines which roles are allowable for laterSET ROLE commands, whereas changing roles withSET ROLE does not change the set of roles allowed to a laterSET ROLE.
SET ROLE does not process session variables as specified by the role'sALTER ROLE settings; this only happens during login.
SET ROLE cannot be used within aSECURITY DEFINER function.
Examples
SELECT SESSION_USER, CURRENT_USER; session_user | current_user --------------+-------------- peter | peterSET 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. TheSESSION andLOCAL modifiers are aPostgreSQL extension, as is theRESET syntax.