在安装之后，如何在mysql中启用联邦引擎?

I have mysql 5.1.44

我有mysql 5.1.44

mysql> show engines;
+------------+---------+
| Engine     | Support | 
+------------+---------+
| ndbcluster | NO      | 
| MRG_MYISAM | YES     | 
| BLACKHOLE  | YES     | 
| CSV        | YES     | 
| MEMORY     | YES     | 
| FEDERATED  | NO      | 
| ARCHIVE    | YES     | 
| InnoDB     | YES     | 
| MyISAM     | DEFAULT |
mysql>