diff --git a/contrib/pg_upgrade/pg_upgrade.c b/contrib/pg_upgrade/pg_upgrade.c
new file mode 100644
index 465ecdd..ba81823
*** a/contrib/pg_upgrade/pg_upgrade.c
--- b/contrib/pg_upgrade/pg_upgrade.c
***************
*** 29,35 ****
   *	We control all assignments of pg_enum.oid because these oids are stored
   *	in user tables as enum values.
   *
!  *	We control all assignments of pg_auth.oid because these oids are stored
   *	in pg_largeobject_metadata.
   */
  
--- 29,35 ----
   *	We control all assignments of pg_enum.oid because these oids are stored
   *	in user tables as enum values.
   *
!  *	We control all assignments of pg_authid.oid because these oids are stored
   *	in pg_largeobject_metadata.
   */
  
diff --git a/contrib/pg_upgrade/check.c b/contrib/pg_upgrade/check.c
new file mode 100644
index 2669c09..df77f53
*** a/contrib/pg_upgrade/check.c
--- b/contrib/pg_upgrade/check.c
*************** static void set_locale_and_encoding(Clus
*** 16,22 ****
  static void check_new_cluster_is_empty(void);
  static void check_locale_and_encoding(ControlData *oldctrl,
  						  ControlData *newctrl);
! static void check_is_super_user(ClusterInfo *cluster);
  static void check_for_prepared_transactions(ClusterInfo *cluster);
  static void check_for_isn_and_int8_passing_mismatch(ClusterInfo *cluster);
  static void check_for_reg_data_type_usage(ClusterInfo *cluster);
--- 16,22 ----
  static void check_new_cluster_is_empty(void);
  static void check_locale_and_encoding(ControlData *oldctrl,
  						  ControlData *newctrl);
! static void check_is_super_user_get_oid(ClusterInfo *cluster);
  static void check_for_prepared_transactions(ClusterInfo *cluster);
  static void check_for_isn_and_int8_passing_mismatch(ClusterInfo *cluster);
  static void check_for_reg_data_type_usage(ClusterInfo *cluster);
*************** check_old_cluster(bool live_check, char
*** 69,75 ****
  	/*
  	 * Check for various failure cases
  	 */
! 	check_is_super_user(&old_cluster);
  	check_for_prepared_transactions(&old_cluster);
  	check_for_reg_data_type_usage(&old_cluster);
  	check_for_isn_and_int8_passing_mismatch(&old_cluster);
--- 69,75 ----
  	/*
  	 * Check for various failure cases
  	 */
! 	check_is_super_user_get_oid(&old_cluster);
  	check_for_prepared_transactions(&old_cluster);
  	check_for_reg_data_type_usage(&old_cluster);
  	check_for_isn_and_int8_passing_mismatch(&old_cluster);
*************** check_new_cluster(void)
*** 121,137 ****
  {
  	set_locale_and_encoding(&new_cluster);
  
  	get_db_and_rel_infos(&new_cluster);
  
  	check_new_cluster_is_empty();
- 	check_for_prepared_transactions(&new_cluster);
  
  	check_loadable_libraries();
  
- 	check_locale_and_encoding(&old_cluster.controldata, &new_cluster.controldata);
- 
  	if (user_opts.transfer_mode == TRANSFER_MODE_LINK)
  		check_hard_link();
  }
  
  
--- 121,144 ----
  {
  	set_locale_and_encoding(&new_cluster);
  
+ 	check_locale_and_encoding(&old_cluster.controldata, &new_cluster.controldata);
+ 
  	get_db_and_rel_infos(&new_cluster);
  
  	check_new_cluster_is_empty();
  
  	check_loadable_libraries();
  
  	if (user_opts.transfer_mode == TRANSFER_MODE_LINK)
  		check_hard_link();
+ 
+     check_is_super_user_get_oid(&new_cluster);
+     /* We don't restore our own user, so both clusters better have equal user oids */
+     if (old_cluster.user_oid != new_cluster.user_oid)
+ 		pg_log(PG_FATAL,
+ 		"Old and new cluster superusers have different values for pg_authid.oid");
+     
+ 	check_for_prepared_transactions(&new_cluster);
  }
  
  
*************** create_script_for_old_cluster_deletion(c
*** 577,588 ****
  
  
  /*
!  *	check_is_super_user()
   *
   *	Make sure we are the super-user.
   */
  static void
! check_is_super_user(ClusterInfo *cluster)
  {
  	PGresult   *res;
  	PGconn	   *conn = connectToServer(cluster, "template1");
--- 584,595 ----
  
  
  /*
!  *	check_is_super_user_get_oid()
   *
   *	Make sure we are the super-user.
   */
  static void
! check_is_super_user_get_oid(ClusterInfo *cluster)
  {
  	PGresult   *res;
  	PGconn	   *conn = connectToServer(cluster, "template1");
*************** check_is_super_user(ClusterInfo *cluster
*** 591,597 ****
  
  	/* Can't use pg_authid because only superusers can view it. */
  	res = executeQueryOrDie(conn,
! 							"SELECT rolsuper "
  							"FROM pg_catalog.pg_roles "
  							"WHERE rolname = current_user");
  
--- 598,604 ----
  
  	/* Can't use pg_authid because only superusers can view it. */
  	res = executeQueryOrDie(conn,
! 							"SELECT rolsuper, oid "
  							"FROM pg_catalog.pg_roles "
  							"WHERE rolname = current_user");
  
*************** check_is_super_user(ClusterInfo *cluster
*** 599,604 ****
--- 606,613 ----
  		pg_log(PG_FATAL, "database user \"%s\" is not a superuser\n",
  			   os_info.user);
  
+ 	cluster->user_oid = atooid(PQgetvalue(res, 0, 1));
+ 
  	PQclear(res);
  
  	PQfinish(conn);
diff --git a/contrib/pg_upgrade/pg_upgrade.h b/contrib/pg_upgrade/pg_upgrade.h
new file mode 100644
index 26aa7bb..ef59c2b
*** a/contrib/pg_upgrade/pg_upgrade.h
--- b/contrib/pg_upgrade/pg_upgrade.h
*************** typedef struct
*** 230,235 ****
--- 230,236 ----
  	char		major_version_str[64];	/* string PG_VERSION of cluster */
  	uint32		bin_version;	/* version returned from pg_ctl */
  	Oid			pg_database_oid;	/* OID of pg_database relation */
+ 	Oid			user_oid;		/* OID of connected user */
  	char	   *tablespace_suffix;		/* directory specification */
  } ClusterInfo;