Federated可以不使用復(fù)制技術(shù)，直接遠程服務(wù)器主機的數(shù)據(jù)表。
實現(xiàn)原理
通過創(chuàng)建存儲引擎為Federated 的表來實現(xiàn)遠程共享服務(wù)器表數(shù)據(jù)。
Federated：能夠?qū)⒍鄠€分離（不在同一臺服務(wù)器上的機器）的MySQL服務(wù)器鏈接起來，從多個物理服務(wù)器創(chuàng)建一個邏輯數(shù)據(jù)庫。十分適合于分布式環(huán)境或數(shù)據(jù)集市環(huán)境。
特點
- 提供了訪問遠程MySQL服務(wù)器上表的方法（連接）
- 本地不存儲數(shù)據(jù)，數(shù)據(jù)全部放到遠程服務(wù)器上
- 本地需要保存表結(jié)構(gòu)(frm文件)和遠程服務(wù)器的連接信息
如何使用
默認(rèn)禁止，啟用需要在啟動時增加federated參數(shù)
mysql://user_name[:password]@host_name[:port_num]/db_name/tbl_name
實例：在本地模擬遠程本地
查看是否支持federated
MySQL [test]> show engines;
+--------------------+---------+----------------------------------------------------------------+--------------+------+------------+
| Engine | Support | Comment | Transactions | XA | Savepoints |
+--------------------+---------+----------------------------------------------------------------+--------------+------+------------+
| InnoDB | DEFAULT | Supports transactions, row-level locking, and foreign keys | YES | YES | YES |
| MRG_MYISAM | YES | Collection of identical MyISAM tables | NO | NO | NO |
| MEMORY | YES | Hash based, stored in memory, useful for temporary tables | NO | NO | NO |
| BLACKHOLE | YES | /dev/null storage engine (anything you write to it disappears) | NO | NO | NO |
| MyISAM | YES | MyISAM storage engine | NO | NO | NO |
| CSV | YES | CSV storage engine | NO | NO | NO |
| ARCHIVE | YES | Archive storage engine | NO | NO | NO |
| PERFORMANCE_SCHEMA | YES | Performance Schema | NO | NO | NO |
| FEDERATED | NO | Federated MySQL storage engine | NULL | NULL | NULL |
+--------------------+---------+----------------------------------------------------------------+--------------+------+------------+
9 rows in set (0.00 sec)
具體使用查看這篇博客<a>http://blog.csdn.net/jenminzhang/article/details/50837603<./a>
使用場景：
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