安装federated存储引擎

Federated存储引擎可以使你在本地数据库中访问远程数据库中的数据，针对federated存储引擎表的查询会被发送到远程数据库的表上执行，本地是不存储任何数据的。

简要介绍后，是不是发现它和Oracle的database link(数据库链接)非常相似，它所实现的功能和db link类似，要在MySQL下找寻db link替代品的，federated存储引擎是不二的选择。

1. 查看当前支持的存储引擎

SQL>show engines;

1. +------------+---------+------------------------------------------------------------+--------------+------+------------+
3. | Engine | Support | Comment | Transactions | XA | Savepoints |
5. +------------+---------+------------------------------------------------------------+--------------+------+------------+
7. | CSV | YES | CSV storage engine | NO | NO | NO |
9. | MRG_MYISAM | YES | Collection of identical MyISAM tables | NO | NO | NO |
11. | MEMORY | YES | Hash based, stored in memory, useful for temporary tables | NO | NO | NO |
13. | InnoDB | DEFAULT | Supports transactions, row-level locking, and foreign keys | YES | YES | YES |
15. | MyISAM | YES | Default engine as of MySQL 3.23 with great performance | NO | NO | NO |
17. +------------+---------+------------------------------------------------------------+--------------+------+------------+
19. 5 rows in set (0.00 sec)

发现安装MySQL时没有编译进来，只能现安装了。

2. 安装federated存储引擎

由于编译时没有选择federated，所以打算通过INSTALL PLUGIN的方式安装，正常情况下，federated是支持动态安装的：

=== Federated Storage Engine ===

Plugin Name: federated

Description: Connects to tables on remote MySQL servers

Supports build: static and dynamic

Configurations: max, max-no-ndb

可是执行以下命令时报错：

SQL>install plugin federated soname 'ha_federated.so';

ERROR 1126 (HY000): Can't open shared library '/usr/local/mysql/lib/mysql/plugin/ha_federated.so' (errno: 2 undefined symbol: dynstr_append_mem)

搜了一下，发现是个老问题，竟然到现在都没解决，可见MySQL团队的效率和管理的混乱。http://bugs.mysql.com/bug.php?id=40942

没有办法了，只有重新编译MySQL源码了, 加上--with-plugins=federated。从5.1.26开始，默认MySQL不启用federated存储引擎，所以需要在my.cnf中加入federated选项或是在命令行用--federated选项启动mysqld。编译后的结果如下：

SQL>show engines;

1. +------------+---------+----------------------------------------------------------------------------+--------------+------+------------+
3. | Engine | Support | Comment | Transactions | XA | Savepoints |
5. +------------+---------+----------------------------------------------------------------------------+--------------+------+------------+
7. | CSV | YES | CSV storage engine | NO | NO | NO |
9. | MRG_MYISAM | YES | Collection of identical MyISAM tables | NO | NO | NO |
11. | FEDERATED | YES | Federated MySQL storage engine | NO | NO | NO |
13. | MyISAM | YES | Default engine as of MySQL 3.23 with great performance | NO | NO | NO |
15. | InnoDB | DEFAULT | Percona-XtraDB, Supports transactions, row-level locking, and foreign keys | YES | YES | YES |
17. | MEMORY | YES | Hash based, stored in memory, useful for temporary tables | NO | NO | NO |
19. +------------+---------+----------------------------------------------------------------------------+--------------+------+------------+
21. 6 rows in set (0.00 sec)

至此，我们已经可以使用federated存储引擎了。

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转载于:http://blog.itpub.net/26690043/viewspace-719996/