diff --git a/contrib/pg_upgrade/check.c b/contrib/pg_upgrade/check.c
new file mode 100644
index 5b9b4cd..e400814
*** a/contrib/pg_upgrade/check.c
--- b/contrib/pg_upgrade/check.c
*************** check_old_cluster_has_new_cluster_dbs(vo
*** 403,410 ****
  					   new_cluster.dbarr.dbs[new_dbnum].db_name) == 0)
  				break;
  		if (old_dbnum == old_cluster.dbarr.ndbs)
! 			pg_log(PG_FATAL, "New cluster database \"%s\" does not exist in the old cluster\n",
! 				   new_cluster.dbarr.dbs[new_dbnum].db_name);
  	}
  }
  
--- 403,415 ----
  					   new_cluster.dbarr.dbs[new_dbnum].db_name) == 0)
  				break;
  		if (old_dbnum == old_cluster.dbarr.ndbs)
! 		{
! 			if (strcmp(new_cluster.dbarr.dbs[new_dbnum].db_name, "postgres") == 0)
! 				pg_log(PG_FATAL, "The \"postgres\" database must exist in the old cluster\n");
! 			else
! 				pg_log(PG_FATAL, "New cluster database \"%s\" does not exist in the old cluster\n",
! 					   new_cluster.dbarr.dbs[new_dbnum].db_name);
! 		}
  	}
  }