Allow CURRENT/SESSION_USER to be used in certain commands

Commands such as ALTER USER, ALTER GROUP, ALTER ROLE, GRANT, and the
various ALTER OBJECT / OWNER TO, as well as ad-hoc clauses related to
roles such as the AUTHORIZATION clause of CREATE SCHEMA, the FOR clause
of CREATE USER MAPPING, and the FOR ROLE clause of ALTER DEFAULT
PRIVILEGES can now take the keywords CURRENT_USER and SESSION_USER as
user specifiers in place of an explicit user name.

This commit also fixes some quite ugly handling of special standards-
mandated syntax in CREATE USER MAPPING, which in particular would fail
to work in presence of a role named "current_user".

The special role specifiers PUBLIC and NONE also have more consistent
handling now.

Also take the opportunity to add location tracking to user specifiers.

Authors: Kyotaro Horiguchi.  Heavily reworked by Álvaro Herrera.
Reviewed by: Rushabh Lathia, Adam Brightwell, Marti Raudsepp.

doc/src/sgml/ref/alter_aggregate.sgml

@@ -22,7 +22,8 @@ PostgreSQL documentation
  <refsynopsisdiv>
 <synopsis>
 ALTER AGGREGATE <replaceable>name</replaceable> ( <replaceable>aggregate_signature</replaceable> ) RENAME TO <replaceable>new_name</replaceable>
-ALTER AGGREGATE <replaceable>name</replaceable> ( <replaceable>aggregate_signature</replaceable> ) OWNER TO <replaceable>new_owner</replaceable>
+ALTER AGGREGATE <replaceable>name</replaceable> ( <replaceable>aggregate_signature</replaceable> )
+                OWNER TO { <replaceable>new_owner</replaceable> | CURRENT_USER | SESSION_USER }
 ALTER AGGREGATE <replaceable>name</replaceable> ( <replaceable>aggregate_signature</replaceable> ) SET SCHEMA <replaceable>new_schema</replaceable>
 
 <phrase>where <replaceable>aggregate_signature</replaceable> is:</phrase>

doc/src/sgml/ref/alter_collation.sgml

@@ -22,7 +22,7 @@ PostgreSQL documentation
  <refsynopsisdiv>
 <synopsis>
 ALTER COLLATION <replaceable>name</replaceable> RENAME TO <replaceable>new_name</replaceable>
-ALTER COLLATION <replaceable>name</replaceable> OWNER TO <replaceable>new_owner</replaceable>
+ALTER COLLATION <replaceable>name</replaceable> OWNER TO { <replaceable>new_owner</replaceable> | CURRENT_USER | SESSION_USER }
 ALTER COLLATION <replaceable>name</replaceable> SET SCHEMA <replaceable>new_schema</replaceable>
 </synopsis>
  </refsynopsisdiv>

doc/src/sgml/ref/alter_conversion.sgml

@@ -22,7 +22,7 @@ PostgreSQL documentation
  <refsynopsisdiv>
 <synopsis>
 ALTER CONVERSION <replaceable>name</replaceable> RENAME TO <replaceable>new_name</replaceable>
-ALTER CONVERSION <replaceable>name</replaceable> OWNER TO <replaceable>new_owner</replaceable>
+ALTER CONVERSION <replaceable>name</replaceable> OWNER TO { <replaceable>new_owner</replaceable> | CURRENT_USER | SESSION_USER }
 ALTER CONVERSION <replaceable>name</replaceable> SET SCHEMA <replaceable>new_schema</replaceable>
 </synopsis>
  </refsynopsisdiv>

doc/src/sgml/ref/alter_database.sgml

@@ -31,7 +31,7 @@ ALTER DATABASE <replaceable class="PARAMETER">name</replaceable> [ [ WITH ] <rep
 
 ALTER DATABASE <replaceable class="PARAMETER">name</replaceable> RENAME TO <replaceable>new_name</replaceable>
 
-ALTER DATABASE <replaceable class="PARAMETER">name</replaceable> OWNER TO <replaceable>new_owner</replaceable>
+ALTER DATABASE <replaceable class="PARAMETER">name</replaceable> OWNER TO { <replaceable>new_owner</replaceable> | CURRENT_USER | SESSION_USER }
 
 ALTER DATABASE <replaceable class="PARAMETER">name</replaceable> SET TABLESPACE <replaceable class="PARAMETER">new_tablespace</replaceable>
 

doc/src/sgml/ref/alter_domain.sgml

@@ -36,7 +36,7 @@ ALTER DOMAIN <replaceable class="PARAMETER">name</replaceable>
 ALTER DOMAIN <replaceable class="PARAMETER">name</replaceable>
     VALIDATE CONSTRAINT <replaceable class="PARAMETER">constraint_name</replaceable>
 ALTER DOMAIN <replaceable class="PARAMETER">name</replaceable>
-    OWNER TO <replaceable class="PARAMETER">new_owner</replaceable>
+    OWNER TO { <replaceable class="PARAMETER">new_owner</replaceable> | CURRENT_USER | SESSION_USER }
 ALTER DOMAIN <replaceable class="PARAMETER">name</replaceable>
     RENAME TO <replaceable class="PARAMETER">new_name</replaceable>
 ALTER DOMAIN <replaceable class="PARAMETER">name</replaceable>

doc/src/sgml/ref/alter_event_trigger.sgml

@@ -23,7 +23,7 @@ PostgreSQL documentation
 <synopsis>
 ALTER EVENT TRIGGER <replaceable class="PARAMETER">name</replaceable> DISABLE
 ALTER EVENT TRIGGER <replaceable class="PARAMETER">name</replaceable> ENABLE [ REPLICA | ALWAYS ]
-ALTER EVENT TRIGGER <replaceable class="PARAMETER">name</replaceable> OWNER TO <replaceable class="PARAMETER">new_owner</replaceable>
+ALTER EVENT TRIGGER <replaceable class="PARAMETER">name</replaceable> OWNER TO { <replaceable class="PARAMETER">new_owner</replaceable> | CURRENT_USER | SESSION_USER }
 ALTER EVENT TRIGGER <replaceable class="PARAMETER">name</replaceable> RENAME TO <replaceable class="PARAMETER">new_name</replaceable>
 </synopsis>
  </refsynopsisdiv>

doc/src/sgml/ref/alter_foreign_data_wrapper.sgml

@@ -25,7 +25,7 @@ ALTER FOREIGN DATA WRAPPER <replaceable class="parameter">name</replaceable>
     [ HANDLER <replaceable class="parameter">handler_function</replaceable> | NO HANDLER ]
     [ VALIDATOR <replaceable class="parameter">validator_function</replaceable> | NO VALIDATOR ]
     [ OPTIONS ( [ ADD | SET | DROP ] <replaceable class="PARAMETER">option</replaceable> ['<replaceable class="PARAMETER">value</replaceable>'] [, ... ]) ]
-ALTER FOREIGN DATA WRAPPER <replaceable class="parameter">name</replaceable> OWNER TO <replaceable>new_owner</replaceable>
+ALTER FOREIGN DATA WRAPPER <replaceable class="parameter">name</replaceable> OWNER TO { <replaceable>new_owner</replaceable> | CURRENT_USER | SESSION_USER }
 ALTER FOREIGN DATA WRAPPER <replaceable class="parameter">name</replaceable> RENAME TO <replaceable>new_name</replaceable>
 </synopsis>
  </refsynopsisdiv>

doc/src/sgml/ref/alter_foreign_table.sgml

@@ -48,7 +48,7 @@ ALTER FOREIGN TABLE [ IF EXISTS ] <replaceable class="PARAMETER">name</replaceab
     ENABLE TRIGGER [ <replaceable class="PARAMETER">trigger_name</replaceable> | ALL | USER ]
     ENABLE REPLICA TRIGGER <replaceable class="PARAMETER">trigger_name</replaceable>
     ENABLE ALWAYS TRIGGER <replaceable class="PARAMETER">trigger_name</replaceable>
-    OWNER TO <replaceable class="PARAMETER">new_owner</replaceable>
+    OWNER TO { <replaceable class="PARAMETER">new_owner</replaceable> | CURRENT_USER | SESSION_USER }
     OPTIONS ( [ ADD | SET | DROP ] <replaceable class="PARAMETER">option</replaceable> ['<replaceable class="PARAMETER">value</replaceable>'] [, ... ])
 </synopsis>
  </refsynopsisdiv>

doc/src/sgml/ref/alter_function.sgml

@@ -26,7 +26,7 @@ ALTER FUNCTION <replaceable>name</replaceable> ( [ [ <replaceable class="paramet
 ALTER FUNCTION <replaceable>name</replaceable> ( [ [ <replaceable class="parameter">argmode</replaceable> ] [ <replaceable class="parameter">argname</replaceable> ] <replaceable class="parameter">argtype</replaceable> [, ...] ] )
     RENAME TO <replaceable>new_name</replaceable>
 ALTER FUNCTION <replaceable>name</replaceable> ( [ [ <replaceable class="parameter">argmode</replaceable> ] [ <replaceable class="parameter">argname</replaceable> ] <replaceable class="parameter">argtype</replaceable> [, ...] ] )
-    OWNER TO <replaceable>new_owner</replaceable>
+    OWNER TO { <replaceable>new_owner</replaceable> | CURRENT_USER | SESSION_USER }
 ALTER FUNCTION <replaceable>name</replaceable> ( [ [ <replaceable class="parameter">argmode</replaceable> ] [ <replaceable class="parameter">argname</replaceable> ] <replaceable class="parameter">argtype</replaceable> [, ...] ] )
     SET SCHEMA <replaceable>new_schema</replaceable>
 

doc/src/sgml/ref/alter_group.sgml

@@ -21,8 +21,14 @@ PostgreSQL documentation
 
  <refsynopsisdiv>
 <synopsis>
-ALTER GROUP <replaceable class="PARAMETER">group_name</replaceable> ADD USER <replaceable class="PARAMETER">user_name</replaceable> [, ... ]
-ALTER GROUP <replaceable class="PARAMETER">group_name</replaceable> DROP USER <replaceable class="PARAMETER">user_name</replaceable> [, ... ]
+ALTER GROUP <replaceable class="PARAMETER">role_specification</replaceable> ADD USER <replaceable class="PARAMETER">user_name</replaceable> [, ... ]
+ALTER GROUP <replaceable class="PARAMETER">role_specification</replaceable> DROP USER <replaceable class="PARAMETER">user_name</replaceable> [, ... ]
+
+<phrase>where <replaceable class="PARAMETER">role_specification</replaceable> can be:</phrase>
+
+    <replaceable class="PARAMETER">role_name</replaceable>
+  | CURRENT_USER
+  | SESSION_USER
 
 ALTER GROUP <replaceable class="PARAMETER">group_name</replaceable> RENAME TO <replaceable>new_name</replaceable>
 </synopsis>

doc/src/sgml/ref/alter_language.sgml

@@ -22,7 +22,7 @@ PostgreSQL documentation
  <refsynopsisdiv>
 <synopsis>
 ALTER [ PROCEDURAL ] LANGUAGE <replaceable>name</replaceable> RENAME TO <replaceable>new_name</replaceable>
-ALTER [ PROCEDURAL ] LANGUAGE <replaceable>name</replaceable> OWNER TO <replaceable>new_owner</replaceable>
+ALTER [ PROCEDURAL ] LANGUAGE <replaceable>name</replaceable> OWNER TO { <replaceable>new_owner</replaceable> | CURRENT_USER | SESSION_USER }
 </synopsis>
  </refsynopsisdiv>
 

doc/src/sgml/ref/alter_large_object.sgml

@@ -21,7 +21,7 @@ PostgreSQL documentation
 
  <refsynopsisdiv>
 <synopsis>
-ALTER LARGE OBJECT <replaceable class="PARAMETER">large_object_oid</replaceable> OWNER TO <replaceable>new_owner</replaceable>
+ALTER LARGE OBJECT <replaceable class="PARAMETER">large_object_oid</replaceable> { OWNER TO <replaceable>new_owner</replaceable> | CURRENT_USER | SESSION_USER }
 </synopsis>
  </refsynopsisdiv>
 

doc/src/sgml/ref/alter_materialized_view.sgml

@@ -42,7 +42,7 @@ ALTER MATERIALIZED VIEW ALL IN TABLESPACE <replaceable class="parameter">name</r
     SET WITHOUT CLUSTER
     SET ( <replaceable class="PARAMETER">storage_parameter</replaceable> = <replaceable class="PARAMETER">value</replaceable> [, ... ] )
     RESET ( <replaceable class="PARAMETER">storage_parameter</replaceable> [, ... ] )
-    OWNER TO <replaceable class="PARAMETER">new_owner</replaceable>
+    OWNER TO { <replaceable class="PARAMETER">new_owner</replaceable> | CURRENT_USER | SESSION_USER }
     SET TABLESPACE <replaceable class="PARAMETER">new_tablespace</replaceable>
 </synopsis>
  </refsynopsisdiv>

doc/src/sgml/ref/alter_opclass.sgml

@@ -21,9 +21,14 @@ PostgreSQL documentation
 
  <refsynopsisdiv>
 <synopsis>
-ALTER OPERATOR CLASS <replaceable>name</replaceable> USING <replaceable class="parameter">index_method</replaceable> RENAME TO <replaceable>new_name</replaceable>
-ALTER OPERATOR CLASS <replaceable>name</replaceable> USING <replaceable class="parameter">index_method</replaceable> OWNER TO <replaceable>new_owner</replaceable>
-ALTER OPERATOR CLASS <replaceable>name</replaceable> USING <replaceable class="parameter">index_method</replaceable> SET SCHEMA <replaceable>new_schema</replaceable>
+ALTER OPERATOR CLASS <replaceable>name</replaceable> USING <replaceable class="parameter">index_method</replaceable>
+           RENAME TO <replaceable>new_name</replaceable>
+
+ALTER OPERATOR CLASS <replaceable>name</replaceable> USING <replaceable class="parameter">index_method</replaceable>
+          { OWNER TO <replaceable>new_owner</replaceable> | CURRENT_USER | SESSION_USER }
+
+ALTER OPERATOR CLASS <replaceable>name</replaceable> USING <replaceable class="parameter">index_method</replaceable>
+          SET SCHEMA <replaceable>new_schema</replaceable>
 </synopsis>
  </refsynopsisdiv>
 

doc/src/sgml/ref/alter_operator.sgml

@@ -21,8 +21,11 @@ PostgreSQL documentation
 
  <refsynopsisdiv>
 <synopsis>
-ALTER OPERATOR <replaceable>name</replaceable> ( { <replaceable>left_type</replaceable> | NONE } , { <replaceable>right_type</replaceable> | NONE } ) OWNER TO <replaceable>new_owner</replaceable>
-ALTER OPERATOR <replaceable>name</replaceable> ( { <replaceable>left_type</replaceable> | NONE } , { <replaceable>right_type</replaceable> | NONE } ) SET SCHEMA <replaceable>new_schema</replaceable>
+ALTER OPERATOR <replaceable>name</replaceable> ( { <replaceable>left_type</replaceable> | NONE } , { <replaceable>right_type</replaceable> | NONE } )
+             { OWNER TO <replaceable>new_owner</replaceable> | CURRENT_USER | SESSION_USER }
+
+ALTER OPERATOR <replaceable>name</replaceable> ( { <replaceable>left_type</replaceable> | NONE } , { <replaceable>right_type</replaceable> | NONE } )
+               SET SCHEMA <replaceable>new_schema</replaceable>
 </synopsis>
  </refsynopsisdiv>
 

doc/src/sgml/ref/alter_opfamily.sgml

@@ -22,16 +22,25 @@ PostgreSQL documentation
  <refsynopsisdiv>
 <synopsis>
 ALTER OPERATOR FAMILY <replaceable>name</replaceable> USING <replaceable class="parameter">index_method</replaceable> ADD
-  {  OPERATOR <replaceable class="parameter">strategy_number</replaceable> <replaceable class="parameter">operator_name</replaceable> ( <replaceable class="parameter">op_type</replaceable>, <replaceable class="parameter">op_type</replaceable> ) [ FOR SEARCH | FOR ORDER BY <replaceable class="parameter">sort_family_name</replaceable> ]
-   | FUNCTION <replaceable class="parameter">support_number</replaceable> [ ( <replaceable class="parameter">op_type</replaceable> [ , <replaceable class="parameter">op_type</replaceable> ] ) ] <replaceable class="parameter">function_name</replaceable> ( <replaceable class="parameter">argument_type</replaceable> [, ...] )
+  {  OPERATOR <replaceable class="parameter">strategy_number</replaceable> <replaceable class="parameter">operator_name</replaceable> ( <replaceable class="parameter">op_type</replaceable>, <replaceable class="parameter">op_type</replaceable> )
+              [ FOR SEARCH | FOR ORDER BY <replaceable class="parameter">sort_family_name</replaceable> ]
+   | FUNCTION <replaceable class="parameter">support_number</replaceable> [ ( <replaceable class="parameter">op_type</replaceable> [ , <replaceable class="parameter">op_type</replaceable> ] ) ]
+              <replaceable class="parameter">function_name</replaceable> ( <replaceable class="parameter">argument_type</replaceable> [, ...] )
   } [, ... ]
+
 ALTER OPERATOR FAMILY <replaceable>name</replaceable> USING <replaceable class="parameter">index_method</replaceable> DROP
   {  OPERATOR <replaceable class="parameter">strategy_number</replaceable> ( <replaceable class="parameter">op_type</replaceable> [ , <replaceable class="parameter">op_type</replaceable> ] )
    | FUNCTION <replaceable class="parameter">support_number</replaceable> ( <replaceable class="parameter">op_type</replaceable> [ , <replaceable class="parameter">op_type</replaceable> ] )
   } [, ... ]
-ALTER OPERATOR FAMILY <replaceable>name</replaceable> USING <replaceable class="parameter">index_method</replaceable> RENAME TO <replaceable>new_name</replaceable>
-ALTER OPERATOR FAMILY <replaceable>name</replaceable> USING <replaceable class="parameter">index_method</replaceable> OWNER TO <replaceable>new_owner</replaceable>
-ALTER OPERATOR FAMILY <replaceable>name</replaceable> USING <replaceable class="parameter">index_method</replaceable> SET SCHEMA <replaceable>new_schema</replaceable>
+
+ALTER OPERATOR FAMILY <replaceable>name</replaceable> USING <replaceable class="parameter">index_method</replaceable>
+            RENAME TO <replaceable>new_name</replaceable>
+
+ALTER OPERATOR FAMILY <replaceable>name</replaceable> USING <replaceable class="parameter">index_method</replaceable>
+             OWNER TO { <replaceable>new_owner</replaceable> | CURRENT_USER | SESSION_USER }
+
+ALTER OPERATOR FAMILY <replaceable>name</replaceable> USING <replaceable class="parameter">index_method</replaceable>
+           SET SCHEMA <replaceable>new_schema</replaceable>
 </synopsis>
  </refsynopsisdiv>
 

doc/src/sgml/ref/alter_role.sgml

@@ -21,7 +21,7 @@ PostgreSQL documentation
 
  <refsynopsisdiv>
 <synopsis>
-ALTER ROLE <replaceable class="PARAMETER">name</replaceable> [ [ WITH ] <replaceable class="PARAMETER">option</replaceable> [ ... ] ]
+ALTER ROLE <replaceable class="PARAMETER">role_specification</replaceable> [ WITH ] <replaceable class="PARAMETER">option</replaceable> [ ... ]
 
 <phrase>where <replaceable class="PARAMETER">option</replaceable> can be:</phrase>
 
@@ -39,10 +39,16 @@ ALTER ROLE <replaceable class="PARAMETER">name</replaceable> [ [ WITH ] <replace
 
 ALTER ROLE <replaceable class="PARAMETER">name</replaceable> RENAME TO <replaceable>new_name</replaceable>
 
-ALTER ROLE <replaceable class="PARAMETER">name</replaceable> [ IN DATABASE <replaceable class="PARAMETER">database_name</replaceable> ] SET <replaceable>configuration_parameter</replaceable> { TO | = } { <replaceable>value</replaceable> | DEFAULT }
-ALTER ROLE { <replaceable class="PARAMETER">name</replaceable> | ALL } [ IN DATABASE <replaceable class="PARAMETER">database_name</replaceable> ] SET <replaceable>configuration_parameter</replaceable> FROM CURRENT
-ALTER ROLE { <replaceable class="PARAMETER">name</replaceable> | ALL } [ IN DATABASE <replaceable class="PARAMETER">database_name</replaceable> ] RESET <replaceable>configuration_parameter</replaceable>
-ALTER ROLE { <replaceable class="PARAMETER">name</replaceable> | ALL } [ IN DATABASE <replaceable class="PARAMETER">database_name</replaceable> ] RESET ALL
+ALTER ROLE { <replaceable class="PARAMETER">role_specification</replaceable> | ALL } [ IN DATABASE <replaceable class="PARAMETER">database_name</replaceable> ] SET <replaceable>configuration_parameter</replaceable> { TO | = } { <replaceable>value</replaceable> | DEFAULT }
+ALTER ROLE { <replaceable class="PARAMETER">role_specification</replaceable> | ALL } [ IN DATABASE <replaceable class="PARAMETER">database_name</replaceable> ] SET <replaceable>configuration_parameter</replaceable> FROM CURRENT
+ALTER ROLE { <replaceable class="PARAMETER">role_specification</replaceable> | ALL } [ IN DATABASE <replaceable class="PARAMETER">database_name</replaceable> ] RESET <replaceable>configuration_parameter</replaceable>
+ALTER ROLE { <replaceable class="PARAMETER">role_specification</replaceable> | ALL } [ IN DATABASE <replaceable class="PARAMETER">database_name</replaceable> ] RESET ALL
+
+<phrase>where <replaceable class="PARAMETER">role_specification</replaceable> can be:</phrase>
+
+    [ GROUP ] <replaceable class="PARAMETER">role_name</replaceable>
+  | CURRENT_USER
+  | SESSION_USER
 </synopsis>
  </refsynopsisdiv>
 
@@ -128,6 +134,25 @@ ALTER ROLE { <replaceable class="PARAMETER">name</replaceable> | ALL } [ IN DATA
       </listitem>
      </varlistentry>
 
+     <varlistentry>
+      <term>CURRENT_USER</term>
+      <listitem>
+       <para>
+        Alter the current user instead of an explicitely identified role.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry>
+      <term>SESSION_USER</term>
+      <listitem>
+       <para>
+        Alter the current session user instead of an explicitely identified
+        role.
+       </para>
+      </listitem>
+     </varlistentry>
+
      <varlistentry>
       <term><literal>SUPERUSER</literal></term>
       <term><literal>NOSUPERUSER</literal></term>

doc/src/sgml/ref/alter_schema.sgml

@@ -22,7 +22,7 @@ PostgreSQL documentation
  <refsynopsisdiv>
 <synopsis>
 ALTER SCHEMA <replaceable>name</replaceable> RENAME TO <replaceable>new_name</replaceable>
-ALTER SCHEMA <replaceable>name</replaceable> OWNER TO <replaceable>new_owner</replaceable>
+ALTER SCHEMA <replaceable>name</replaceable> OWNER TO { <replaceable>new_owner</replaceable> | CURRENT_USER | SESSION_USER }
 </synopsis>
  </refsynopsisdiv>
 

doc/src/sgml/ref/alter_sequence.sgml

@@ -29,7 +29,7 @@ ALTER SEQUENCE [ IF EXISTS ] <replaceable class="parameter">name</replaceable> [
     [ RESTART [ [ WITH ] <replaceable class="parameter">restart</replaceable> ] ]
     [ CACHE <replaceable class="parameter">cache</replaceable> ] [ [ NO ] CYCLE ]
     [ OWNED BY { <replaceable class="parameter">table_name</replaceable>.<replaceable class="parameter">column_name</replaceable> | NONE } ]
-ALTER SEQUENCE [ IF EXISTS ] <replaceable class="parameter">name</replaceable> OWNER TO <replaceable class="PARAMETER">new_owner</replaceable>
+ALTER SEQUENCE [ IF EXISTS ] <replaceable class="parameter">name</replaceable> OWNER TO { <replaceable class="PARAMETER">new_owner</replaceable> | CURRENT_USER | SESSION_USER }
 ALTER SEQUENCE [ IF EXISTS ] <replaceable class="parameter">name</replaceable> RENAME TO <replaceable class="parameter">new_name</replaceable>
 ALTER SEQUENCE [ IF EXISTS ] <replaceable class="parameter">name</replaceable> SET SCHEMA <replaceable class="parameter">new_schema</replaceable>
 </synopsis>

doc/src/sgml/ref/alter_server.sgml

@@ -23,7 +23,7 @@ PostgreSQL documentation
 <synopsis>
 ALTER SERVER <replaceable class="parameter">name</replaceable> [ VERSION '<replaceable class="parameter">new_version</replaceable>' ]
     [ OPTIONS ( [ ADD | SET | DROP ] <replaceable class="PARAMETER">option</replaceable> ['<replaceable class="PARAMETER">value</replaceable>'] [, ... ] ) ]
-ALTER SERVER <replaceable class="PARAMETER">name</replaceable> OWNER TO <replaceable>new_owner</replaceable>
+ALTER SERVER <replaceable class="PARAMETER">name</replaceable> OWNER TO { <replaceable>new_owner</replaceable> | CURRENT_USER | SESSION_USER }
 ALTER SERVER <replaceable class="PARAMETER">name</replaceable> RENAME TO <replaceable>new_name</replaceable>
 </synopsis>
  </refsynopsisdiv>

doc/src/sgml/ref/alter_table.sgml

@@ -73,7 +73,7 @@ ALTER TABLE ALL IN TABLESPACE <replaceable class="PARAMETER">name</replaceable>
     NO INHERIT <replaceable class="PARAMETER">parent_table</replaceable>
     OF <replaceable class="PARAMETER">type_name</replaceable>
     NOT OF
-    OWNER TO <replaceable class="PARAMETER">new_owner</replaceable>
+    OWNER TO { <replaceable class="PARAMETER">new_owner</replaceable> | CURRENT_USER | SESSION_USER }
     REPLICA IDENTITY {DEFAULT | USING INDEX <replaceable class="PARAMETER">index_name</replaceable> | FULL | NOTHING}
 
 <phrase>and <replaceable class="PARAMETER">table_constraint_using_index</replaceable> is:</phrase>

doc/src/sgml/ref/alter_tablespace.sgml

@@ -22,7 +22,7 @@ PostgreSQL documentation
  <refsynopsisdiv>
 <synopsis>
 ALTER TABLESPACE <replaceable>name</replaceable> RENAME TO <replaceable>new_name</replaceable>
-ALTER TABLESPACE <replaceable>name</replaceable> OWNER TO <replaceable>new_owner</replaceable>
+ALTER TABLESPACE <replaceable>name</replaceable> OWNER TO { <replaceable>new_owner</replaceable> | CURRENT_USER | SESSION_USER }
 ALTER TABLESPACE <replaceable>name</replaceable> SET ( <replaceable class="PARAMETER">tablespace_option</replaceable> = <replaceable class="PARAMETER">value</replaceable> [, ... ] )
 ALTER TABLESPACE <replaceable>name</replaceable> RESET ( <replaceable class="PARAMETER">tablespace_option</replaceable> [, ... ] )
 </synopsis>

doc/src/sgml/ref/alter_tsconfig.sgml

@@ -32,7 +32,7 @@ ALTER TEXT SEARCH CONFIGURATION <replaceable>name</replaceable>
 ALTER TEXT SEARCH CONFIGURATION <replaceable>name</replaceable>
     DROP MAPPING [ IF EXISTS ] FOR <replaceable class="parameter">token_type</replaceable> [, ... ]
 ALTER TEXT SEARCH CONFIGURATION <replaceable>name</replaceable> RENAME TO <replaceable>new_name</replaceable>
-ALTER TEXT SEARCH CONFIGURATION <replaceable>name</replaceable> OWNER TO <replaceable>new_owner</replaceable>
+ALTER TEXT SEARCH CONFIGURATION <replaceable>name</replaceable> OWNER TO { <replaceable>new_owner</replaceable> | CURRENT_USER | SESSION_USER }
 ALTER TEXT SEARCH CONFIGURATION <replaceable>name</replaceable> SET SCHEMA <replaceable>new_schema</replaceable>
 </synopsis>
  </refsynopsisdiv>

doc/src/sgml/ref/alter_tsdictionary.sgml

@@ -25,7 +25,7 @@ ALTER TEXT SEARCH DICTIONARY <replaceable>name</replaceable> (
     <replaceable class="parameter">option</replaceable> [ = <replaceable class="parameter">value</replaceable> ] [, ... ]
 )
 ALTER TEXT SEARCH DICTIONARY <replaceable>name</replaceable> RENAME TO <replaceable>new_name</replaceable>
-ALTER TEXT SEARCH DICTIONARY <replaceable>name</replaceable> OWNER TO <replaceable>new_owner</replaceable>
+ALTER TEXT SEARCH DICTIONARY <replaceable>name</replaceable> OWNER TO { <replaceable>new_owner</replaceable> | CURRENT_USER | SESSION_USER }
 ALTER TEXT SEARCH DICTIONARY <replaceable>name</replaceable> SET SCHEMA <replaceable>new_schema</replaceable>
 </synopsis>
  </refsynopsisdiv>

doc/src/sgml/ref/alter_type.sgml

@@ -24,7 +24,7 @@ PostgreSQL documentation
  <refsynopsisdiv>
 <synopsis>
 ALTER TYPE <replaceable class="PARAMETER">name</replaceable> <replaceable class="PARAMETER">action</replaceable> [, ... ]
-ALTER TYPE <replaceable class="PARAMETER">name</replaceable> OWNER TO <replaceable class="PARAMETER">new_owner</replaceable>
+ALTER TYPE <replaceable class="PARAMETER">name</replaceable> OWNER TO { <replaceable class="PARAMETER">new_owner</replaceable> | CURRENT_USER | SESSION_USER }
 ALTER TYPE <replaceable class="PARAMETER">name</replaceable> RENAME ATTRIBUTE <replaceable class="PARAMETER">attribute_name</replaceable> TO <replaceable class="PARAMETER">new_attribute_name</replaceable> [ CASCADE | RESTRICT ]
 ALTER TYPE <replaceable class="PARAMETER">name</replaceable> RENAME TO <replaceable class="PARAMETER">new_name</replaceable>
 ALTER TYPE <replaceable class="PARAMETER">name</replaceable> SET SCHEMA <replaceable class="PARAMETER">new_schema</replaceable>

doc/src/sgml/ref/alter_user.sgml

@@ -21,7 +21,7 @@ PostgreSQL documentation
 
  <refsynopsisdiv>
 <synopsis>
-ALTER USER <replaceable class="PARAMETER">name</replaceable> [ [ WITH ] <replaceable class="PARAMETER">option</replaceable> [ ... ] ]
+ALTER USER <replaceable class="PARAMETER">role_specification</replaceable> [ WITH ] <replaceable class="PARAMETER">option</replaceable> [ ... ]
 
 <phrase>where <replaceable class="PARAMETER">option</replaceable> can be:</phrase>
 
@@ -38,10 +38,16 @@ ALTER USER <replaceable class="PARAMETER">name</replaceable> [ [ WITH ] <replace
 
 ALTER USER <replaceable class="PARAMETER">name</replaceable> RENAME TO <replaceable>new_name</replaceable>
 
-ALTER USER <replaceable class="PARAMETER">name</replaceable> SET <replaceable>configuration_parameter</replaceable> { TO | = } { <replaceable>value</replaceable> | DEFAULT }
-ALTER USER <replaceable class="PARAMETER">name</replaceable> SET <replaceable>configuration_parameter</replaceable> FROM CURRENT
-ALTER USER <replaceable class="PARAMETER">name</replaceable> RESET <replaceable>configuration_parameter</replaceable>
-ALTER USER <replaceable class="PARAMETER">name</replaceable> RESET ALL
+ALTER USER <replaceable class="PARAMETER">role_specification</replaceable> SET <replaceable>configuration_parameter</replaceable> { TO | = } { <replaceable>value</replaceable> | DEFAULT }
+ALTER USER <replaceable class="PARAMETER">role_specification</replaceable> SET <replaceable>configuration_parameter</replaceable> FROM CURRENT
+ALTER USER <replaceable class="PARAMETER">role_specification</replaceable> RESET <replaceable>configuration_parameter</replaceable>
+ALTER USER <replaceable class="PARAMETER">role_specification</replaceable> RESET ALL
+
+<phrase>where <replaceable class="PARAMETER">role_specification</replaceable> can be:</phrase>
+
+    [ GROUP ] <replaceable class="PARAMETER">role_name</replaceable>
+  | CURRENT_USER
+  | SESSION_USER
 </synopsis>
  </refsynopsisdiv>
 

doc/src/sgml/ref/alter_user_mapping.sgml

@@ -21,7 +21,7 @@ PostgreSQL documentation
 
  <refsynopsisdiv>
 <synopsis>
-ALTER USER MAPPING FOR { <replaceable class="parameter">user_name</replaceable> | USER | CURRENT_USER | PUBLIC }
+ALTER USER MAPPING FOR { <replaceable class="parameter">user_name</replaceable> | USER | CURRENT_USER | SESSION_USER | PUBLIC }
     SERVER <replaceable class="parameter">server_name</replaceable>
     OPTIONS ( [ ADD | SET | DROP ] <replaceable class="PARAMETER">option</replaceable> ['<replaceable class="PARAMETER">value</replaceable>'] [, ... ] )
 </synopsis>

doc/src/sgml/ref/alter_view.sgml

@@ -23,7 +23,7 @@ PostgreSQL documentation
 <synopsis>
 ALTER VIEW [ IF EXISTS ] <replaceable class="parameter">name</replaceable> ALTER [ COLUMN ] <replaceable class="PARAMETER">column_name</replaceable> SET DEFAULT <replaceable class="PARAMETER">expression</replaceable>
 ALTER VIEW [ IF EXISTS ] <replaceable class="parameter">name</replaceable> ALTER [ COLUMN ] <replaceable class="PARAMETER">column_name</replaceable> DROP DEFAULT
-ALTER VIEW [ IF EXISTS ] <replaceable class="parameter">name</replaceable> OWNER TO <replaceable class="PARAMETER">new_owner</replaceable>
+ALTER VIEW [ IF EXISTS ] <replaceable class="parameter">name</replaceable> OWNER TO { <replaceable class="PARAMETER">new_owner</replaceable> | CURRENT_USER | SESSION_USER }
 ALTER VIEW [ IF EXISTS ] <replaceable class="parameter">name</replaceable> RENAME TO <replaceable class="parameter">new_name</replaceable>
 ALTER VIEW [ IF EXISTS ] <replaceable class="parameter">name</replaceable> SET SCHEMA <replaceable class="parameter">new_schema</replaceable>
 ALTER VIEW [ IF EXISTS ] <replaceable class="parameter">name</replaceable> SET ( <replaceable class="parameter">view_option_name</replaceable> [= <replaceable class="parameter">view_option_value</replaceable>] [, ... ] )

doc/src/sgml/ref/create_schema.sgml

@@ -21,10 +21,16 @@ PostgreSQL documentation
 
  <refsynopsisdiv>
 <synopsis>
-CREATE SCHEMA <replaceable class="parameter">schema_name</replaceable> [ AUTHORIZATION <replaceable class="parameter">user_name</replaceable> ] [ <replaceable class="parameter">schema_element</replaceable> [ ... ] ]
-CREATE SCHEMA AUTHORIZATION <replaceable class="parameter">user_name</replaceable> [ <replaceable class="parameter">schema_element</replaceable> [ ... ] ]
-CREATE SCHEMA IF NOT EXISTS <replaceable class="parameter">schema_name</replaceable> [ AUTHORIZATION <replaceable class="parameter">user_name</replaceable> ]
-CREATE SCHEMA IF NOT EXISTS AUTHORIZATION <replaceable class="parameter">user_name</replaceable>
+CREATE SCHEMA <replaceable class="parameter">schema_name</replaceable> [ AUTHORIZATION <replaceable class="PARAMETER">role_specification</replaceable> ] [ <replaceable class="parameter">schema_element</replaceable> [ ... ] ]
+CREATE SCHEMA AUTHORIZATION <replaceable class="PARAMETER">role_specification</replaceable> [ <replaceable class="parameter">schema_element</replaceable> [ ... ] ]
+CREATE SCHEMA IF NOT EXISTS <replaceable class="parameter">schema_name</replaceable> [ AUTHORIZATION <replaceable class="PARAMETER">role_specification</replaceable> ]
+CREATE SCHEMA IF NOT EXISTS AUTHORIZATION <replaceable class="PARAMETER">role_specification</replaceable>
+
+<phrase>where <replaceable class="PARAMETER">role_specification</replaceable> can be:</phrase>
+
+    [ GROUP ] <replaceable class="PARAMETER">user_name</replaceable>
+  | CURRENT_USER
+  | SESSION_USER
 </synopsis>
  </refsynopsisdiv>
 

doc/src/sgml/ref/grant.sgml

@@ -25,59 +25,66 @@ GRANT { { SELECT | INSERT | UPDATE | DELETE | TRUNCATE | REFERENCES | TRIGGER }
     [, ...] | ALL [ PRIVILEGES ] }
     ON { [ TABLE ] <replaceable class="PARAMETER">table_name</replaceable> [, ...]
          | ALL TABLES IN SCHEMA <replaceable class="PARAMETER">schema_name</replaceable> [, ...] }
-    TO { [ GROUP ] <replaceable class="PARAMETER">role_name</replaceable> | PUBLIC } [, ...] [ WITH GRANT OPTION ]
+    TO <replaceable class="PARAMETER">role_specification</replaceable> [, ...] [ WITH GRANT OPTION ]
 
 GRANT { { SELECT | INSERT | UPDATE | REFERENCES } ( <replaceable class="PARAMETER">column_name</replaceable> [, ...] )
     [, ...] | ALL [ PRIVILEGES ] ( <replaceable class="PARAMETER">column_name</replaceable> [, ...] ) }
     ON [ TABLE ] <replaceable class="PARAMETER">table_name</replaceable> [, ...]
-    TO { [ GROUP ] <replaceable class="PARAMETER">role_name</replaceable> | PUBLIC } [, ...] [ WITH GRANT OPTION ]
+    TO <replaceable class="PARAMETER">role_specification</replaceable> [, ...] [ WITH GRANT OPTION ]
 
 GRANT { { USAGE | SELECT | UPDATE }
     [, ...] | ALL [ PRIVILEGES ] }
     ON { SEQUENCE <replaceable class="PARAMETER">sequence_name</replaceable> [, ...]
          | ALL SEQUENCES IN SCHEMA <replaceable class="PARAMETER">schema_name</replaceable> [, ...] }
-    TO { [ GROUP ] <replaceable class="PARAMETER">role_name</replaceable> | PUBLIC } [, ...] [ WITH GRANT OPTION ]
+    TO <replaceable class="PARAMETER">role_specification</replaceable> [, ...] [ WITH GRANT OPTION ]
 
 GRANT { { CREATE | CONNECT | TEMPORARY | TEMP } [, ...] | ALL [ PRIVILEGES ] }
     ON DATABASE <replaceable>database_name</replaceable> [, ...]
-    TO { [ GROUP ] <replaceable class="PARAMETER">role_name</replaceable> | PUBLIC } [, ...] [ WITH GRANT OPTION ]
+    TO <replaceable class="PARAMETER">role_specification</replaceable> [, ...] [ WITH GRANT OPTION ]
 
 GRANT { USAGE | ALL [ PRIVILEGES ] }
     ON DOMAIN <replaceable>domain_name</replaceable> [, ...]
-    TO { [ GROUP ] <replaceable class="PARAMETER">role_name</replaceable> | PUBLIC } [, ...] [ WITH GRANT OPTION ]
+    TO <replaceable class="PARAMETER">role_specification</replaceable> [, ...] [ WITH GRANT OPTION ]
 
 GRANT { USAGE | ALL [ PRIVILEGES ] }
     ON FOREIGN DATA WRAPPER <replaceable>fdw_name</replaceable> [, ...]
-    TO { [ GROUP ] <replaceable class="PARAMETER">role_name</replaceable> | PUBLIC } [, ...] [ WITH GRANT OPTION ]
+    TO <replaceable class="PARAMETER">role_specification</replaceable> [, ...] [ WITH GRANT OPTION ]
 
 GRANT { USAGE | ALL [ PRIVILEGES ] }
     ON FOREIGN SERVER <replaceable>server_name</replaceable> [, ...]
-    TO { [ GROUP ] <replaceable class="PARAMETER">role_name</replaceable> | PUBLIC } [, ...] [ WITH GRANT OPTION ]
+    TO <replaceable class="PARAMETER">role_specification</replaceable> [, ...] [ WITH GRANT OPTION ]
 
 GRANT { EXECUTE | ALL [ PRIVILEGES ] }
     ON { FUNCTION <replaceable>function_name</replaceable> ( [ [ <replaceable class="parameter">argmode</replaceable> ] [ <replaceable class="parameter">arg_name</replaceable> ] <replaceable class="parameter">arg_type</replaceable> [, ...] ] ) [, ...]
          | ALL FUNCTIONS IN SCHEMA <replaceable class="PARAMETER">schema_name</replaceable> [, ...] }
-    TO { [ GROUP ] <replaceable class="PARAMETER">role_name</replaceable> | PUBLIC } [, ...] [ WITH GRANT OPTION ]
+    TO <replaceable class="PARAMETER">role_specification</replaceable> [, ...] [ WITH GRANT OPTION ]
 
 GRANT { USAGE | ALL [ PRIVILEGES ] }
     ON LANGUAGE <replaceable>lang_name</replaceable> [, ...]
-    TO { [ GROUP ] <replaceable class="PARAMETER">role_name</replaceable> | PUBLIC } [, ...] [ WITH GRANT OPTION ]
+    TO <replaceable class="PARAMETER">role_specification</replaceable> [, ...] [ WITH GRANT OPTION ]
 
 GRANT { { SELECT | UPDATE } [, ...] | ALL [ PRIVILEGES ] }
     ON LARGE OBJECT <replaceable class="PARAMETER">loid</replaceable> [, ...]
-    TO { [ GROUP ] <replaceable class="PARAMETER">role_name</replaceable> | PUBLIC } [, ...] [ WITH GRANT OPTION ]
+    TO <replaceable class="PARAMETER">role_specification</replaceable> [, ...] [ WITH GRANT OPTION ]
 
 GRANT { { CREATE | USAGE } [, ...] | ALL [ PRIVILEGES ] }
     ON SCHEMA <replaceable>schema_name</replaceable> [, ...]
-    TO { [ GROUP ] <replaceable class="PARAMETER">role_name</replaceable> | PUBLIC } [, ...] [ WITH GRANT OPTION ]
+    TO <replaceable class="PARAMETER">role_specification</replaceable> [, ...] [ WITH GRANT OPTION ]
 
 GRANT { CREATE | ALL [ PRIVILEGES ] }
     ON TABLESPACE <replaceable>tablespace_name</replaceable> [, ...]
-    TO { [ GROUP ] <replaceable class="PARAMETER">role_name</replaceable> | PUBLIC } [, ...] [ WITH GRANT OPTION ]
+    TO <replaceable class="PARAMETER">role_specification</replaceable> [, ...] [ WITH GRANT OPTION ]
 
 GRANT { USAGE | ALL [ PRIVILEGES ] }
     ON TYPE <replaceable>type_name</replaceable> [, ...]
-    TO { [ GROUP ] <replaceable class="PARAMETER">role_name</replaceable> | PUBLIC } [, ...] [ WITH GRANT OPTION ]
+    TO <replaceable class="PARAMETER">role_specification</replaceable> [, ...] [ WITH GRANT OPTION ]
+
+<phrase>where <replaceable class="PARAMETER">role_specification</replaceable> can be:</phrase>
+
+    [ GROUP ] <replaceable class="PARAMETER">role_name</replaceable>
+  | PUBLIC
+  | CURRENT_USER
+  | SESSION_USER
 
 GRANT <replaceable class="PARAMETER">role_name</replaceable> [, ...] TO <replaceable class="PARAMETER">role_name</replaceable> [, ...] [ WITH ADMIN OPTION ]
 </synopsis>

src/backend/catalog/aclchk.c

@@ -421,22 +421,25 @@ ExecuteGrantStmt(GrantStmt *stmt)
 	istmt.behavior = stmt->behavior;
 
 	/*
-	 * Convert the PrivGrantee list into an Oid list.  Note that at this point
-	 * we insert an ACL_ID_PUBLIC into the list if an empty role name is
-	 * detected (which is what the grammar uses if PUBLIC is found), so
-	 * downstream there shouldn't be any additional work needed to support
-	 * this case.
+	 * Convert the RoleSpec list into an Oid list.  Note that at this point
+	 * we insert an ACL_ID_PUBLIC into the list if appropriate, so downstream
+	 * there shouldn't be any additional work needed to support this case.
 	 */
 	foreach(cell, stmt->grantees)
 	{
-		PrivGrantee *grantee = (PrivGrantee *) lfirst(cell);
+		RoleSpec *grantee = (RoleSpec *) lfirst(cell);
+		Oid grantee_uid;
 
-		if (grantee->rolname == NULL)
-			istmt.grantees = lappend_oid(istmt.grantees, ACL_ID_PUBLIC);
-		else
-			istmt.grantees =
-				lappend_oid(istmt.grantees,
-							get_role_oid(grantee->rolname, false));
+		switch (grantee->roletype)
+		{
+			case ROLESPEC_PUBLIC:
+				grantee_uid = ACL_ID_PUBLIC;
+				break;
+			default:
+				grantee_uid = get_rolespec_oid((Node *) grantee, false);
+				break;
+		}
+		istmt.grantees = lappend_oid(istmt.grantees, grantee_uid);
 	}
 
 	/*
@@ -904,22 +907,25 @@ ExecAlterDefaultPrivilegesStmt(AlterDefaultPrivilegesStmt *stmt)
 	iacls.behavior = action->behavior;
 
 	/*
-	 * Convert the PrivGrantee list into an Oid list.  Note that at this point
-	 * we insert an ACL_ID_PUBLIC into the list if an empty role name is
-	 * detected (which is what the grammar uses if PUBLIC is found), so
-	 * downstream there shouldn't be any additional work needed to support
-	 * this case.
+	 * Convert the RoleSpec list into an Oid list.  Note that at this point
+	 * we insert an ACL_ID_PUBLIC into the list if appropriate, so downstream
+	 * there shouldn't be any additional work needed to support this case.
 	 */
 	foreach(cell, action->grantees)
 	{
-		PrivGrantee *grantee = (PrivGrantee *) lfirst(cell);
+		RoleSpec *grantee = (RoleSpec *) lfirst(cell);
+		Oid grantee_uid;
 
-		if (grantee->rolname == NULL)
-			iacls.grantees = lappend_oid(iacls.grantees, ACL_ID_PUBLIC);
-		else
-			iacls.grantees =
-				lappend_oid(iacls.grantees,
-							get_role_oid(grantee->rolname, false));
+		switch (grantee->roletype)
+		{
+			case ROLESPEC_PUBLIC:
+				grantee_uid = ACL_ID_PUBLIC;
+				break;
+			default:
+				grantee_uid = get_rolespec_oid((Node *) grantee, false);
+				break;
+		}
+		iacls.grantees = lappend_oid(iacls.grantees, grantee_uid);
 	}
 
 	/*

src/backend/commands/alter.c

@@ -699,7 +699,7 @@ AlterObjectNamespace_internal(Relation rel, Oid objid, Oid nspOid)
 ObjectAddress
 ExecAlterOwnerStmt(AlterOwnerStmt *stmt)
 {
-	Oid			newowner = get_role_oid(stmt->newowner, false);
+	Oid			newowner = get_rolespec_oid(stmt->newowner, false);
 
 	switch (stmt->objectType)
 	{

src/backend/commands/extension.c

@@ -1371,7 +1371,7 @@ CreateExtension(CreateExtensionStmt *stmt)
 			CreateSchemaStmt *csstmt = makeNode(CreateSchemaStmt);
 
 			csstmt->schemaname = schemaName;
-			csstmt->authid = NULL;		/* will be created by current user */
+			csstmt->authrole = NULL;	/* will be created by current user */
 			csstmt->schemaElts = NIL;
 			csstmt->if_not_exists = false;
 			CreateSchemaCommand(csstmt, NULL);

src/backend/commands/foreigncmds.c

@@ -197,24 +197,6 @@ transformGenericOptions(Oid catalogId,
 }
 
 
-/*
- * Convert the user mapping user name to OID
- */
-static Oid
-GetUserOidFromMapping(const char *username, bool missing_ok)
-{
-	if (!username)
-		/* PUBLIC user mapping */
-		return InvalidOid;
-
-	if (strcmp(username, "current_user") == 0)
-		/* map to the owner */
-		return GetUserId();
-
-	/* map to provided user */
-	return get_role_oid(username, missing_ok);
-}
-
 /*
  * Internal workhorse for changing a data wrapper's owner.
  *
@@ -1156,10 +1138,14 @@ CreateUserMapping(CreateUserMappingStmt *stmt)
 	ObjectAddress referenced;
 	ForeignServer *srv;
 	ForeignDataWrapper *fdw;
+	RoleSpec   *role = (RoleSpec *) stmt->user;
 
 	rel = heap_open(UserMappingRelationId, RowExclusiveLock);
 
-	useId = GetUserOidFromMapping(stmt->username, false);
+	if (role->roletype == ROLESPEC_PUBLIC)
+		useId = ACL_ID_PUBLIC;
+	else
+		useId = get_rolespec_oid(stmt->user, false);
 
 	/* Check that the server exists. */
 	srv = GetForeignServerByName(stmt->servername, false);
@@ -1252,10 +1238,15 @@ AlterUserMapping(AlterUserMappingStmt *stmt)
 	Oid			umId;
 	ForeignServer *srv;
 	ObjectAddress address;
+	RoleSpec   *role = (RoleSpec *) stmt->user;
 
 	rel = heap_open(UserMappingRelationId, RowExclusiveLock);
 
-	useId = GetUserOidFromMapping(stmt->username, false);
+	if (role->roletype == ROLESPEC_PUBLIC)
+		useId = ACL_ID_PUBLIC;
+	else
+		useId = get_rolespec_oid(stmt->user, false);
+
 	srv = GetForeignServerByName(stmt->servername, false);
 
 	umId = GetSysCacheOid2(USERMAPPINGUSERSERVER,
@@ -1338,19 +1329,26 @@ RemoveUserMapping(DropUserMappingStmt *stmt)
 	Oid			useId;
 	Oid			umId;
 	ForeignServer *srv;
+	RoleSpec   *role = (RoleSpec *) stmt->user;
 
-	useId = GetUserOidFromMapping(stmt->username, stmt->missing_ok);
-	srv = GetForeignServerByName(stmt->servername, true);
-
-	if (stmt->username && !OidIsValid(useId))
+	if (role->roletype == ROLESPEC_PUBLIC)
+		useId = ACL_ID_PUBLIC;
+	else
+	{
+		useId = get_rolespec_oid(stmt->user, stmt->missing_ok);
+		if (!OidIsValid(useId))
 		{
 			/*
-		 * IF EXISTS specified, role not found and not public. Notice this and
-		 * leave.
+			 * IF EXISTS specified, role not found and not public. Notice this
+			 * and leave.
 			 */
-		elog(NOTICE, "role \"%s\" does not exist, skipping", stmt->username);
+			elog(NOTICE, "role \"%s\" does not exist, skipping",
+				 role->rolename);
 			return InvalidOid;
 		}
+	}
+
+	srv = GetForeignServerByName(stmt->servername, true);
 
 	if (!srv)
 	{

src/backend/commands/policy.c

@@ -129,13 +129,7 @@ parse_policy_command(const char *cmd_name)
 
 /*
  * policy_role_list_to_array
- *   helper function to convert a list of role names in to an array of
- *   role ids.
- *
- * Note: If PUBLIC is provided as a role name, then ACL_ID_PUBLIC is
- *       used as the role id.
- *
- * roles - the list of role names to convert.
+ *   helper function to convert a list of RoleSpecs to an array of role ids.
  */
 static ArrayType *
 policy_role_list_to_array(List *roles)
@@ -162,25 +156,25 @@ policy_role_list_to_array(List *roles)
 
 	foreach(cell, roles)
 	{
-		Oid		roleid = get_role_oid_or_public(strVal(lfirst(cell)));
+		RoleSpec *spec = lfirst(cell);
 
 		/*
 		 * PUBLIC covers all roles, so it only makes sense alone.
 		 */
-		if (roleid == ACL_ID_PUBLIC)
+		if (spec->roletype == ROLESPEC_PUBLIC)
 		{
 			if (num_roles != 1)
 				ereport(WARNING,
 						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 						 errmsg("ignoring roles specified other than public"),
 						 errhint("All roles are members of the public role.")));
-
-			temp_array[0] = ObjectIdGetDatum(roleid);
+			temp_array[0] = ObjectIdGetDatum(ACL_ID_PUBLIC);
 			num_roles = 1;
 			break;
 		}
 		else
-			temp_array[i++] = ObjectIdGetDatum(roleid);
+			temp_array[i++] =
+				ObjectIdGetDatum(get_rolespec_oid((Node *) spec, false));
 	}
 
 	role_ids = construct_array(temp_array, num_roles, OIDOID, sizeof(Oid), true,

src/backend/commands/schemacmds.c

@@ -21,6 +21,7 @@
 #include "catalog/dependency.h"
 #include "catalog/indexing.h"
 #include "catalog/namespace.h"
+#include "catalog/pg_authid.h"
 #include "catalog/objectaccess.h"
 #include "catalog/pg_namespace.h"
 #include "commands/dbcommands.h"
@@ -43,7 +44,6 @@ Oid
 CreateSchemaCommand(CreateSchemaStmt *stmt, const char *queryString)
 {
 	const char	*schemaName = stmt->schemaname;
-	const char *authId = stmt->authid;
 	Oid			namespaceId;
 	OverrideSearchPath *overridePath;
 	List	   *parsetree_list;
@@ -58,11 +58,24 @@ CreateSchemaCommand(CreateSchemaStmt *stmt, const char *queryString)
 	/*
 	 * Who is supposed to own the new schema?
 	 */
-	if (authId)
-		owner_uid = get_role_oid(authId, false);
+	if (stmt->authrole)
+		owner_uid = get_rolespec_oid(stmt->authrole, false);
 	else
 		owner_uid = saved_uid;
 
+	/* fill schema name with the user name if not specified */
+	if (!schemaName)
+	{
+		HeapTuple tuple;
+
+		tuple = SearchSysCache1(AUTHOID, ObjectIdGetDatum(owner_uid));
+		if (!HeapTupleIsValid(tuple))
+			elog(ERROR, "cache lookup failed for role %u", owner_uid);
+		schemaName =
+			pstrdup(NameStr(((Form_pg_authid) GETSTRUCT(tuple))->rolname));
+		ReleaseSysCache(tuple);
+	}
+
 	/*
 	 * To create a schema, must have schema-create privilege on the current
 	 * database and must be able to become the target role (this does not

src/backend/commands/tablecmds.c

@@ -3507,7 +3507,7 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
 			break;
 		case AT_ChangeOwner:	/* ALTER OWNER */
 			ATExecChangeOwner(RelationGetRelid(rel),
-							  get_role_oid(cmd->name, false),
+							  get_rolespec_oid(cmd->newowner, false),
 							  false, lockmode);
 			break;
 		case AT_ClusterOn:		/* CLUSTER ON */
@@ -9388,7 +9388,7 @@ AlterTableMoveAll(AlterTableMoveAllStmt *stmt)
 	HeapTuple	tuple;
 	Oid			orig_tablespaceoid;
 	Oid			new_tablespaceoid;
-	List	   *role_oids = roleNamesToIds(stmt->roles);
+	List	   *role_oids = roleSpecsToIds(stmt->roles);
 
 	/* Ensure we were not asked to move something we can't */
 	if (stmt->objtype != OBJECT_TABLE && stmt->objtype != OBJECT_INDEX &&

src/backend/commands/tablespace.c

@@ -252,7 +252,7 @@ CreateTableSpace(CreateTableSpaceStmt *stmt)
 
 	/* However, the eventual owner of the tablespace need not be */
 	if (stmt->owner)
-		ownerId = get_role_oid(stmt->owner, false);
+		ownerId = get_rolespec_oid(stmt->owner, false);
 	else
 		ownerId = GetUserId();
 

src/backend/nodes/copyfuncs.c

@@ -2504,6 +2504,18 @@ _copyXmlSerialize(const XmlSerialize *from)
 	return newnode;
 }
 
+static RoleSpec *
+_copyRoleSpec(const RoleSpec *from)
+{
+	RoleSpec *newnode = makeNode(RoleSpec);
+
+	COPY_SCALAR_FIELD(roletype);
+	COPY_STRING_FIELD(rolename);
+	COPY_LOCATION_FIELD(location);
+
+	return newnode;
+}
+
 static Query *
 _copyQuery(const Query *from)
 {
@@ -2650,6 +2662,7 @@ _copyAlterTableCmd(const AlterTableCmd *from)
 
 	COPY_SCALAR_FIELD(subtype);
 	COPY_STRING_FIELD(name);
+	COPY_NODE_FIELD(newowner);
 	COPY_NODE_FIELD(def);
 	COPY_SCALAR_FIELD(behavior);
 	COPY_SCALAR_FIELD(missing_ok);
@@ -2689,16 +2702,6 @@ _copyGrantStmt(const GrantStmt *from)
 	return newnode;
 }
 
-static PrivGrantee *
-_copyPrivGrantee(const PrivGrantee *from)
-{
-	PrivGrantee *newnode = makeNode(PrivGrantee);
-
-	COPY_STRING_FIELD(rolname);
-
-	return newnode;
-}
-
 static FuncWithArgs *
 _copyFuncWithArgs(const FuncWithArgs *from)
 {
@@ -2730,7 +2733,7 @@ _copyGrantRoleStmt(const GrantRoleStmt *from)
 	COPY_NODE_FIELD(grantee_roles);
 	COPY_SCALAR_FIELD(is_grant);
 	COPY_SCALAR_FIELD(admin_opt);
-	COPY_STRING_FIELD(grantor);
+	COPY_NODE_FIELD(grantor);
 	COPY_SCALAR_FIELD(behavior);
 
 	return newnode;
@@ -3038,7 +3041,7 @@ _copyAlterOwnerStmt(const AlterOwnerStmt *from)
 	COPY_NODE_FIELD(relation);
 	COPY_NODE_FIELD(object);
 	COPY_NODE_FIELD(objarg);
-	COPY_STRING_FIELD(newowner);
+	COPY_NODE_FIELD(newowner);
 
 	return newnode;
 }
@@ -3424,7 +3427,7 @@ _copyCreateTableSpaceStmt(const CreateTableSpaceStmt *from)
 	CreateTableSpaceStmt *newnode = makeNode(CreateTableSpaceStmt);
 
 	COPY_STRING_FIELD(tablespacename);
-	COPY_STRING_FIELD(owner);
+	COPY_NODE_FIELD(owner);
 	COPY_STRING_FIELD(location);
 	COPY_NODE_FIELD(options);
 
@@ -3561,7 +3564,7 @@ _copyCreateUserMappingStmt(const CreateUserMappingStmt *from)
 {
 	CreateUserMappingStmt *newnode = makeNode(CreateUserMappingStmt);
 
-	COPY_STRING_FIELD(username);
+	COPY_NODE_FIELD(user);
 	COPY_STRING_FIELD(servername);
 	COPY_NODE_FIELD(options);
 
@@ -3573,7 +3576,7 @@ _copyAlterUserMappingStmt(const AlterUserMappingStmt *from)
 {
 	AlterUserMappingStmt *newnode = makeNode(AlterUserMappingStmt);
 
-	COPY_STRING_FIELD(username);
+	COPY_NODE_FIELD(user);
 	COPY_STRING_FIELD(servername);
 	COPY_NODE_FIELD(options);
 
@@ -3585,7 +3588,7 @@ _copyDropUserMappingStmt(const DropUserMappingStmt *from)
 {
 	DropUserMappingStmt *newnode = makeNode(DropUserMappingStmt);
 
-	COPY_STRING_FIELD(username);
+	COPY_NODE_FIELD(user);
 	COPY_STRING_FIELD(servername);
 	COPY_SCALAR_FIELD(missing_ok);
 
@@ -3698,7 +3701,7 @@ _copyAlterRoleStmt(const AlterRoleStmt *from)
 {
 	AlterRoleStmt *newnode = makeNode(AlterRoleStmt);
 
-	COPY_STRING_FIELD(role);
+	COPY_NODE_FIELD(role);
 	COPY_NODE_FIELD(options);
 	COPY_SCALAR_FIELD(action);
 
@@ -3710,7 +3713,7 @@ _copyAlterRoleSetStmt(const AlterRoleSetStmt *from)
 {
 	AlterRoleSetStmt *newnode = makeNode(AlterRoleSetStmt);
 
-	COPY_STRING_FIELD(role);
+	COPY_NODE_FIELD(role);
 	COPY_STRING_FIELD(database);
 	COPY_NODE_FIELD(setstmt);
 
@@ -3769,7 +3772,7 @@ _copyCreateSchemaStmt(const CreateSchemaStmt *from)
 	CreateSchemaStmt *newnode = makeNode(CreateSchemaStmt);
 
 	COPY_STRING_FIELD(schemaname);
-	COPY_STRING_FIELD(authid);
+	COPY_NODE_FIELD(authrole);
 	COPY_NODE_FIELD(schemaElts);
 	COPY_SCALAR_FIELD(if_not_exists);
 
@@ -3854,7 +3857,7 @@ _copyReassignOwnedStmt(const ReassignOwnedStmt *from)
 	ReassignOwnedStmt *newnode = makeNode(ReassignOwnedStmt);
 
 	COPY_NODE_FIELD(roles);
-	COPY_STRING_FIELD(newrole);
+	COPY_NODE_FIELD(newrole);
 
 	return newnode;
 }
@@ -4728,9 +4731,6 @@ copyObject(const void *from)
 		case T_CommonTableExpr:
 			retval = _copyCommonTableExpr(from);
 			break;
-		case T_PrivGrantee:
-			retval = _copyPrivGrantee(from);
-			break;
 		case T_FuncWithArgs:
 			retval = _copyFuncWithArgs(from);
 			break;
@@ -4740,6 +4740,9 @@ copyObject(const void *from)
 		case T_XmlSerialize:
 			retval = _copyXmlSerialize(from);
 			break;
+		case T_RoleSpec:
+			retval = _copyRoleSpec(from);
+			break;
 
 		default:
 			elog(ERROR, "unrecognized node type: %d", (int) nodeTag(from));

src/backend/nodes/equalfuncs.c

@@ -973,6 +973,7 @@ _equalAlterTableCmd(const AlterTableCmd *a, const AlterTableCmd *b)
 {
 	COMPARE_SCALAR_FIELD(subtype);
 	COMPARE_STRING_FIELD(name);
+	COMPARE_NODE_FIELD(newowner);
 	COMPARE_NODE_FIELD(def);
 	COMPARE_SCALAR_FIELD(behavior);
 	COMPARE_SCALAR_FIELD(missing_ok);
@@ -1008,14 +1009,6 @@ _equalGrantStmt(const GrantStmt *a, const GrantStmt *b)
 	return true;
 }
 
-static bool
-_equalPrivGrantee(const PrivGrantee *a, const PrivGrantee *b)
-{
-	COMPARE_STRING_FIELD(rolname);
-
-	return true;
-}
-
 static bool
 _equalFuncWithArgs(const FuncWithArgs *a, const FuncWithArgs *b)
 {
@@ -1041,7 +1034,7 @@ _equalGrantRoleStmt(const GrantRoleStmt *a, const GrantRoleStmt *b)
 	COMPARE_NODE_FIELD(grantee_roles);
 	COMPARE_SCALAR_FIELD(is_grant);
 	COMPARE_SCALAR_FIELD(admin_opt);
-	COMPARE_STRING_FIELD(grantor);
+	COMPARE_NODE_FIELD(grantor);
 	COMPARE_SCALAR_FIELD(behavior);
 
 	return true;
@@ -1295,7 +1288,7 @@ _equalAlterOwnerStmt(const AlterOwnerStmt *a, const AlterOwnerStmt *b)
 	COMPARE_NODE_FIELD(relation);
 	COMPARE_NODE_FIELD(object);
 	COMPARE_NODE_FIELD(objarg);
-	COMPARE_STRING_FIELD(newowner);
+	COMPARE_NODE_FIELD(newowner);
 
 	return true;
 }
@@ -1618,7 +1611,7 @@ static bool
 _equalCreateTableSpaceStmt(const CreateTableSpaceStmt *a, const CreateTableSpaceStmt *b)
 {
 	COMPARE_STRING_FIELD(tablespacename);
-	COMPARE_STRING_FIELD(owner);
+	COMPARE_NODE_FIELD(owner);
 	COMPARE_STRING_FIELD(location);
 	COMPARE_NODE_FIELD(options);
 
@@ -1735,7 +1728,7 @@ _equalAlterForeignServerStmt(const AlterForeignServerStmt *a, const AlterForeign
 static bool
 _equalCreateUserMappingStmt(const CreateUserMappingStmt *a, const CreateUserMappingStmt *b)
 {
-	COMPARE_STRING_FIELD(username);
+	COMPARE_NODE_FIELD(user);
 	COMPARE_STRING_FIELD(servername);
 	COMPARE_NODE_FIELD(options);
 
@@ -1745,7 +1738,7 @@ _equalCreateUserMappingStmt(const CreateUserMappingStmt *a, const CreateUserMapp
 static bool
 _equalAlterUserMappingStmt(const AlterUserMappingStmt *a, const AlterUserMappingStmt *b)
 {
-	COMPARE_STRING_FIELD(username);
+	COMPARE_NODE_FIELD(user);
 	COMPARE_STRING_FIELD(servername);
 	COMPARE_NODE_FIELD(options);
 
@@ -1755,7 +1748,7 @@ _equalAlterUserMappingStmt(const AlterUserMappingStmt *a, const AlterUserMapping
 static bool
 _equalDropUserMappingStmt(const DropUserMappingStmt *a, const DropUserMappingStmt *b)
 {
-	COMPARE_STRING_FIELD(username);
+	COMPARE_NODE_FIELD(user);
 	COMPARE_STRING_FIELD(servername);
 	COMPARE_SCALAR_FIELD(missing_ok);
 
@@ -1853,7 +1846,7 @@ _equalCreateRoleStmt(const CreateRoleStmt *a, const CreateRoleStmt *b)
 static bool
 _equalAlterRoleStmt(const AlterRoleStmt *a, const AlterRoleStmt *b)
 {
-	COMPARE_STRING_FIELD(role);
+	COMPARE_NODE_FIELD(role);
 	COMPARE_NODE_FIELD(options);
 	COMPARE_SCALAR_FIELD(action);
 
@@ -1863,7 +1856,7 @@ _equalAlterRoleStmt(const AlterRoleStmt *a, const AlterRoleStmt *b)
 static bool
 _equalAlterRoleSetStmt(const AlterRoleSetStmt *a, const AlterRoleSetStmt *b)
 {
-	COMPARE_STRING_FIELD(role);
+	COMPARE_NODE_FIELD(role);
 	COMPARE_STRING_FIELD(database);
 	COMPARE_NODE_FIELD(setstmt);
 
@@ -1912,7 +1905,7 @@ static bool
 _equalCreateSchemaStmt(const CreateSchemaStmt *a, const CreateSchemaStmt *b)
 {
 	COMPARE_STRING_FIELD(schemaname);
-	COMPARE_STRING_FIELD(authid);
+	COMPARE_NODE_FIELD(authrole);
 	COMPARE_NODE_FIELD(schemaElts);
 	COMPARE_SCALAR_FIELD(if_not_exists);
 
@@ -1983,7 +1976,7 @@ static bool
 _equalReassignOwnedStmt(const ReassignOwnedStmt *a, const ReassignOwnedStmt *b)
 {
 	COMPARE_NODE_FIELD(roles);
-	COMPARE_STRING_FIELD(newrole);
+	COMPARE_NODE_FIELD(newrole);
 
 	return true;
 }
@@ -2455,6 +2448,16 @@ _equalXmlSerialize(const XmlSerialize *a, const XmlSerialize *b)
 	return true;
 }
 
+static bool
+_equalRoleSpec(const RoleSpec *a, const RoleSpec *b)
+{
+	COMPARE_SCALAR_FIELD(roletype);
+	COMPARE_STRING_FIELD(rolename);
+	COMPARE_LOCATION_FIELD(location);
+
+	return true;
+}
+
 /*
  * Stuff from pg_list.h
  */
@@ -3153,9 +3156,6 @@ equal(const void *a, const void *b)
 		case T_CommonTableExpr:
 			retval = _equalCommonTableExpr(a, b);
 			break;
-		case T_PrivGrantee:
-			retval = _equalPrivGrantee(a, b);
-			break;
 		case T_FuncWithArgs:
 			retval = _equalFuncWithArgs(a, b);
 			break;
@@ -3165,6 +3165,9 @@ equal(const void *a, const void *b)
 		case T_XmlSerialize:
 			retval = _equalXmlSerialize(a, b);
 			break;
+		case T_RoleSpec:
+			retval = _equalRoleSpec(a, b);
+			break;
 
 		default:
 			elog(ERROR, "unrecognized node type: %d",

src/backend/parser/parse_utilcmd.c

@@ -90,7 +90,7 @@ typedef struct
 {
 	const char *stmtType;		/* "CREATE SCHEMA" or "ALTER SCHEMA" */
 	char	   *schemaname;		/* name of schema */
-	char	   *authid;			/* owner of schema */
+	RoleSpec   *authrole;		/* owner of schema */
 	List	   *sequences;		/* CREATE SEQUENCE items */
 	List	   *tables;			/* CREATE TABLE items */
 	List	   *views;			/* CREATE VIEW items */
@@ -2723,7 +2723,7 @@ transformCreateSchemaStmt(CreateSchemaStmt *stmt)
 
 	cxt.stmtType = "CREATE SCHEMA";
 	cxt.schemaname = stmt->schemaname;
-	cxt.authid = stmt->authid;
+	cxt.authrole = (RoleSpec *) stmt->authrole;
 	cxt.sequences = NIL;
 	cxt.tables = NIL;
 	cxt.views = NIL;

src/backend/utils/adt/acl.c

@@ -5105,7 +5105,7 @@ select_best_grantor(Oid roleId, AclMode privileges,
 /*
  * get_role_oid - Given a role name, look up the role's OID.
  *
- * If missing_ok is false, throw an error if tablespace name not found.  If
+ * If missing_ok is false, throw an error if role name not found.  If
  * true, just return InvalidOid.
  */
 Oid
@@ -5133,3 +5133,117 @@ get_role_oid_or_public(const char *rolname)
 
 	return get_role_oid(rolname, false);
 }
+
+/*
+ * Given a RoleSpec node, return the OID it corresponds to.  If missing_ok is
+ * true, return InvalidOid if the role does not exist.
+ *
+ * PUBLIC is always disallowed here.  Routines wanting to handle the PUBLIC
+ * case must check the case separately.
+ */
+Oid
+get_rolespec_oid(const Node *node, bool missing_ok)
+{
+	RoleSpec   *role;
+	Oid			oid;
+
+	if (!IsA(node, RoleSpec))
+		elog(ERROR, "invalid node type %d", node->type);
+
+	role = (RoleSpec *) node;
+	switch (role->roletype)
+	{
+		case ROLESPEC_CSTRING:
+			Assert(role->rolename);
+			oid = get_role_oid(role->rolename, missing_ok);
+			break;
+
+		case ROLESPEC_CURRENT_USER:
+			oid = GetUserId();
+			break;
+
+		case ROLESPEC_SESSION_USER:
+			oid = GetSessionUserId();
+			break;
+
+		case ROLESPEC_PUBLIC:
+			ereport(ERROR,
+					(errcode(ERRCODE_UNDEFINED_OBJECT),
+					 errmsg("role \"%s\" does not exist", "public")));
+			oid = InvalidOid;	/* make compiler happy */
+			break;
+
+		default:
+			elog(ERROR, "unexpected role type %d", role->roletype);
+	}
+
+	return oid;
+}
+
+/*
+ * Given a RoleSpec node, return the pg_authid HeapTuple it corresponds to.
+ * Caller must ReleaseSysCache when done with the result tuple.
+ */
+HeapTuple
+get_rolespec_tuple(const Node *node)
+{
+	RoleSpec   *role;
+	HeapTuple	tuple;
+
+	role = (RoleSpec *) node;
+	if (!IsA(node, RoleSpec))
+		elog(ERROR, "invalid node type %d", node->type);
+
+	switch (role->roletype)
+	{
+		case ROLESPEC_CSTRING:
+			Assert(role->rolename);
+			tuple = SearchSysCache1(AUTHNAME, CStringGetDatum(role->rolename));
+			if (!HeapTupleIsValid(tuple))
+				ereport(ERROR,
+						(errcode(ERRCODE_UNDEFINED_OBJECT),
+						 errmsg("role \"%s\" does not exist", role->rolename)));
+			break;
+
+		case ROLESPEC_CURRENT_USER:
+			tuple = SearchSysCache1(AUTHOID, GetUserId());
+			if (!HeapTupleIsValid(tuple))
+				elog(ERROR, "cache lookup failed for role %u", GetUserId());
+			break;
+
+		case ROLESPEC_SESSION_USER:
+			tuple = SearchSysCache1(AUTHOID, GetSessionUserId());
+			if (!HeapTupleIsValid(tuple))
+				elog(ERROR, "cache lookup failed for role %u", GetSessionUserId());
+			break;
+
+		case ROLESPEC_PUBLIC:
+			ereport(ERROR,
+					(errcode(ERRCODE_UNDEFINED_OBJECT),
+					 errmsg("role \"%s\" does not exist", "public")));
+			tuple = NULL;	/* make compiler happy */
+
+		default:
+			elog(ERROR, "unexpected role type %d", role->roletype);
+	}
+
+	return tuple;
+}
+
+/*
+ * Given a RoleSpec, returns a palloc'ed copy of the corresponding role's name.
+ */
+char *
+get_rolespec_name(const Node *node)
+{
+	HeapTuple	tp;
+	Form_pg_authid authForm;
+	char	   *rolename;
+
+	tp = get_rolespec_tuple(node);
+	authForm = (Form_pg_authid) GETSTRUCT(tp);
+	rolename = pstrdup(NameStr(authForm->rolname));
+	ReleaseSysCache(tp);
+
+	return rolename;
+}

src/include/commands/user.h

@@ -31,6 +31,6 @@ extern void GrantRole(GrantRoleStmt *stmt);
 extern ObjectAddress RenameRole(const char *oldname, const char *newname);
 extern void DropOwnedObjects(DropOwnedStmt *stmt);
 extern void ReassignOwnedObjects(ReassignOwnedStmt *stmt);
-extern List *roleNamesToIds(List *memberNames);
+extern List *roleSpecsToIds(List *memberNames);
 
 #endif   /* USER_H */

src/include/nodes/nodes.h

@@ -413,6 +413,7 @@ typedef enum NodeTag
 	T_XmlSerialize,
 	T_WithClause,
 	T_CommonTableExpr,
+	T_RoleSpec,
 
 	/*
 	 * TAGS FOR REPLICATION GRAMMAR PARSE NODES (replnodes.h)

src/include/nodes/parsenodes.h

@@ -284,6 +284,25 @@ typedef struct CollateClause
 	int			location;		/* token location, or -1 if unknown */
 } CollateClause;
 
+/*
+ * RoleSpec - a role name or one of a few special values.
+ */
+typedef enum RoleSpecType
+{
+	ROLESPEC_CSTRING,		/* role name is stored as a C string */
+	ROLESPEC_CURRENT_USER,	/* role spec is CURRENT_USER */
+	ROLESPEC_SESSION_USER,	/* role spec is SESSION_USER */
+	ROLESPEC_PUBLIC			/* role name is "public" */
+} RoleSpecType;
+
+typedef struct RoleSpec
+{
+	NodeTag		type;
+	RoleSpecType roletype;	/* Type of this rolespec */
+	char	   *rolename;	/* filled only for ROLESPEC_CSTRING */
+	int			location;	/* token location, or -1 if unknown */
+} RoleSpec;
+
 /*
  * FuncCall - a function or aggregate invocation
  *
@@ -1263,7 +1282,7 @@ typedef struct CreateSchemaStmt
 {
 	NodeTag		type;
 	char	   *schemaname;		/* the name of the schema to create */
-	char	   *authid;			/* the owner of the created schema */
+	Node	   *authrole;		/* the owner of the created schema */
 	List	   *schemaElts;		/* schema components (list of parsenodes) */
 	bool		if_not_exists;	/* just do nothing if schema already exists? */
 } CreateSchemaStmt;
@@ -1362,7 +1381,8 @@ typedef struct AlterTableCmd	/* one subcommand of an ALTER TABLE */
 	NodeTag		type;
 	AlterTableType subtype;		/* Type of table alteration to apply */
 	char	   *name;			/* column, constraint, or trigger to act on,
-								 * or new owner or tablespace */
+								 * or tablespace */
+	Node	   *newowner;		/* RoleSpec */
 	Node	   *def;			/* definition of new column, index,
 								 * constraint, or parent table */
 	DropBehavior behavior;		/* RESTRICT or CASCADE for DROP cases */
@@ -1434,17 +1454,11 @@ typedef struct GrantStmt
 								 * or plain names (as Value strings) */
 	List	   *privileges;		/* list of AccessPriv nodes */
 	/* privileges == NIL denotes ALL PRIVILEGES */
-	List	   *grantees;		/* list of PrivGrantee nodes */
+	List	   *grantees;		/* list of RoleSpec nodes */
 	bool		grant_option;	/* grant or revoke grant option */
 	DropBehavior behavior;		/* drop behavior (for REVOKE) */
 } GrantStmt;
 
-typedef struct PrivGrantee
-{
-	NodeTag		type;
-	char	   *rolname;		/* if NULL then PUBLIC */
-} PrivGrantee;
-
 /*
  * Note: FuncWithArgs carries only the types of the input parameters of the
  * function.  So it is sufficient to identify an existing function, but it
@@ -1487,7 +1501,7 @@ typedef struct GrantRoleStmt
 	List	   *grantee_roles;	/* list of member roles to add/delete */
 	bool		is_grant;		/* true = GRANT, false = REVOKE */
 	bool		admin_opt;		/* with admin option */
-	char	   *grantor;		/* set grantor to other than current role */
+	Node	   *grantor;		/* set grantor to other than current role */
 	DropBehavior behavior;		/* drop behavior (for REVOKE) */
 } GrantRoleStmt;
 
@@ -1699,7 +1713,7 @@ typedef struct CreateTableSpaceStmt
 {
 	NodeTag		type;
 	char	   *tablespacename;
-	char	   *owner;
+	Node	   *owner;
 	char	   *location;
 	List	   *options;
 } CreateTableSpaceStmt;
@@ -1825,7 +1839,7 @@ typedef struct CreateForeignTableStmt
 typedef struct CreateUserMappingStmt
 {
 	NodeTag		type;
-	char	   *username;		/* username or PUBLIC/CURRENT_USER */
+	Node	   *user;			/* user role */
 	char	   *servername;		/* server name */
 	List	   *options;		/* generic options to server */
 } CreateUserMappingStmt;
@@ -1833,7 +1847,7 @@ typedef struct CreateUserMappingStmt
 typedef struct AlterUserMappingStmt
 {
 	NodeTag		type;
-	char	   *username;		/* username or PUBLIC/CURRENT_USER */
+	Node	   *user;			/* user role */
 	char	   *servername;		/* server name */
 	List	   *options;		/* generic options to server */
 } AlterUserMappingStmt;
@@ -1841,7 +1855,7 @@ typedef struct AlterUserMappingStmt
 typedef struct DropUserMappingStmt
 {
 	NodeTag		type;
-	char	   *username;		/* username or PUBLIC/CURRENT_USER */
+	Node	   *user;			/* user role */
 	char	   *servername;		/* server name */
 	bool		missing_ok;		/* ignore missing mappings */
 } DropUserMappingStmt;
@@ -1991,7 +2005,7 @@ typedef struct CreateRoleStmt
 typedef struct AlterRoleStmt
 {
 	NodeTag		type;
-	char	   *role;			/* role name */
+	Node	   *role;			/* role */
 	List	   *options;		/* List of DefElem nodes */
 	int			action;			/* +1 = add members, -1 = drop members */
 } AlterRoleStmt;
@@ -1999,7 +2013,7 @@ typedef struct AlterRoleStmt
 typedef struct AlterRoleSetStmt
 {
 	NodeTag		type;
-	char	   *role;			/* role name */
+	Node	   *role;			/* role */
 	char	   *database;		/* database name, or NULL */
 	VariableSetStmt *setstmt;	/* SET or RESET subcommand */
 } AlterRoleSetStmt;
@@ -2375,7 +2389,7 @@ typedef struct AlterOwnerStmt
 	RangeVar   *relation;		/* in case it's a table */
 	List	   *object;			/* in case it's some other object */
 	List	   *objarg;			/* argument types, if applicable */
-	char	   *newowner;		/* the new owner */
+	Node	   *newowner;		/* the new owner */
 } AlterOwnerStmt;
 
 
@@ -2831,7 +2845,7 @@ typedef struct ReassignOwnedStmt
 {
 	NodeTag		type;
 	List	   *roles;
-	char	   *newrole;
+	Node	   *newrole;
 } ReassignOwnedStmt;
 
 /*

src/include/utils/acl.h

@@ -24,6 +24,7 @@
 #ifndef ACL_H
 #define ACL_H
 
+#include "access/htup.h"
 #include "nodes/parsenodes.h"
 #include "utils/array.h"
 #include "utils/snapshot.h"
@@ -227,8 +228,11 @@ extern bool is_member_of_role(Oid member, Oid role);
 extern bool is_member_of_role_nosuper(Oid member, Oid role);
 extern bool is_admin_of_role(Oid member, Oid role);
 extern void check_is_member_of_role(Oid member, Oid role);
-extern Oid	get_role_oid(const char *rolname, bool missing_ok);
-extern Oid	get_role_oid_or_public(const char *rolname);
+extern Oid	get_role_oid(const char *rolename, bool missing_ok);
+extern Oid	get_role_oid_or_public(const char *rolename);
+extern Oid  get_rolespec_oid(const Node *node, bool missing_ok);
+extern HeapTuple get_rolespec_tuple(const Node *node);
+extern char *get_rolespec_name(const Node *node);
 
 extern void select_best_grantor(Oid roleId, AclMode privileges,
 					const Acl *acl, Oid ownerId,

src/test/regress/parallel_schedule

@@ -59,7 +59,7 @@ test: create_index create_view
 # ----------
 # Another group of parallel tests
 # ----------
-test: create_aggregate create_function_3 create_cast constraints triggers inherit create_table_like typed_table vacuum drop_if_exists updatable_views
+test: create_aggregate create_function_3 create_cast constraints triggers inherit create_table_like typed_table vacuum drop_if_exists updatable_views rolenames
 
 # ----------
 # sanity_check does a vacuum, affecting the sort order of SELECT *

src/test/regress/serial_schedule

@@ -71,6 +71,7 @@ test: typed_table
 test: vacuum
 test: drop_if_exists
 test: updatable_views
+test: rolenames
 test: sanity_check
 test: errors
 test: select