Checking to decide whether relations are system relations now depends

on the namespace not the name; pg_ is not a reserved prefix for table
names anymore.  From Fernando Nasser.

src/test/regress/expected/alter_table.out

@@ -296,6 +296,9 @@ SELECT * FROM foo_seq_new;
 (1 row)
 
 DROP SEQUENCE foo_seq_new;
+-- toast-like relation name
+alter table stud_emp rename to pg_toast_stud_emp;
+alter table pg_toast_stud_emp rename to stud_emp;
 -- FOREIGN KEY CONSTRAINT adding TEST
 CREATE TABLE tmp2 (a int primary key);
 NOTICE:  CREATE TABLE / PRIMARY KEY will create implicit index 'tmp2_pkey' for table 'tmp2'

src/test/regress/expected/errors.out

@@ -66,9 +66,6 @@ ERROR:  Relation "nonesuch" does not exist
 -- no such relation 
 alter table nonesuch rename to stud_emp;
 ERROR:  Relation "nonesuch" does not exist
--- system relation 
-alter table stud_emp rename to pg_stud_emp;
-ERROR:  renamerel: Illegal class name: "pg_stud_emp" -- pg_ is reserved for system catalogs
 -- conflict 
 alter table stud_emp rename to aggtest;
 ERROR:  renamerel: relation "aggtest" exists

src/test/regress/sql/alter_table.sql

@@ -178,6 +178,9 @@ CREATE SEQUENCE foo_seq;
 ALTER TABLE foo_seq RENAME TO foo_seq_new;
 SELECT * FROM foo_seq_new;
 DROP SEQUENCE foo_seq_new;
+-- toast-like relation name
+alter table stud_emp rename to pg_toast_stud_emp;
+alter table pg_toast_stud_emp rename to stud_emp;
 
 -- FOREIGN KEY CONSTRAINT adding TEST
 

src/test/regress/sql/errors.sql

@@ -77,9 +77,6 @@ alter table nonesuch rename to newnonesuch;
 -- no such relation 
 alter table nonesuch rename to stud_emp;
 
--- system relation 
-alter table stud_emp rename to pg_stud_emp;
-
 -- conflict 
 alter table stud_emp rename to aggtest;