|PostgreSQL Reference Manual - Volume 1 - SQL Language Reference|
by The PostgreSQL Global Development Group
Paperback (6"x9"), 716 pages
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12.104 SET SESSION AUTHORIZATION
SET SESSION AUTHORIZATION -- set the session user identifier and the current user identifier of the current session
SET [ SESSION | LOCAL ] SESSION AUTHORIZATION username SET [ SESSION | LOCAL ] SESSION AUTHORIZATION DEFAULT RESET SESSION AUTHORIZATION
This command sets the session user identifier and the current user identifier of the current SQL-session context to be username. The user name may 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
may change temporarily in the context of “setuid”
functions and similar mechanisms; it can also be changed by
The current user identifier is relevant for permission checking.
The session user identifier may 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.
LOCAL modifiers act the same
as for the regular
RESET forms reset the session
and current user identifiers to be the originally authenticated user
name. These forms may be executed by any user.
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
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.
LOCAL modifiers are a
PostgreSQL extension, as is the
The privileges necessary to execute this command are left implementation-defined by the standard.
|ISBN 0954612027||PostgreSQL Reference Manual - Volume 1 - SQL Language Reference||See the print edition|