使用FREDATED引擎实现跨实例访问

跨数据库服务器，跨实例访问是比较常见的一种访问方式，在Oracle中可以通过DB LINK的方式来实现。对于MySQL而言，有一个FEDERATED存储引擎与之相对应。同样也是通过创建一个链接方式的形式来访问远程服务器上的数据。本文简要描述了FEDERATED存储引擎，以及

跨数据库服务器，跨实例访问是比较常见的一种访问方式，在Oracle中可以通过DB LINK的方式来实现。对于MySQL而言，有一个FEDERATED存储引擎与之相对应。同样也是通过创建一个链接方式的形式来访问远程服务器上的数据。本文简要描述了FEDERATED存储引擎，以及演示了基于FEDERATED存储引擎跨实例访问的示例。

1、FEDERATED存储引擎的描述

2、安装与启用FEDERATED存储引擎

3、准备远程服务器环境

-- 此演示中远程服务器与本地服务器为同一服务器上的多版本多实例
-- 假定远程服务为：5.6.12(实例3406)
-- 假定本地服务器：5.6.21(实例3306)   
-- 基于实例3306创建FEDERATED存储引擎表test.federated_engine以到达访问实例3406数据库tempdb.tb_engine的目的

[root@rhel64a ~]# cat /etc/issue
Red Hat Enterprise Linux Server release 6.4 (Santiago) 

--启动3406的实例
[root@rhel64a ~]# /u01/app/mysql/bin/mysqld_multi start 3406
[root@rhel64a ~]# mysql -uroot -pxxx -P3406 --protocol=tcp

root@localhost[(none)]> show variables like 'server_id';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| server_id     | 3406  |
+---------------+-------+

--实例3406的版本号
root@localhost[tempdb]> show variables like 'version';
+---------------+------------+
| Variable_name | Value      |
+---------------+------------+
| version       | 5.6.12-log |
+---------------+------------+

--创建数据库
root@localhost[(none)]> create database tempdb;
Query OK, 1 row affected (0.00 sec)

-- Author : Leshami
-- Blog   ：http://blog.csdn.net/leshami

root@localhost[(none)]> use tempdb
Database changed

--创建用于访问的表
root@localhost[tempdb]> create table tb_engine as 
    -> select engine,support,comment from information_schema.engines;
Query OK, 9 rows affected (0.10 sec)
Records: 9  Duplicates: 0  Warnings: 0

--提取表的SQL语句用于创建为FEDERATED存储引擎表
root@localhost[tempdb]> show create table tb_engine \G
*************************** 1. row ***************************
       Table: tb_engine
Create Table: CREATE TABLE `tb_engine` (
  `engine` varchar(64) NOT NULL DEFAULT '',
  `support` varchar(8) NOT NULL DEFAULT '',
  `comment` varchar(80) NOT NULL DEFAULT ''
) ENGINE=InnoDB DEFAULT CHARSET=utf8

--创建用于远程访问的账户
root@localhost[tempdb]> grant all privileges on tempdb.* to 'remote_user'@'192.168.1.131' identified by 'xxx';
Query OK, 0 rows affected (0.00 sec)

root@localhost[tempdb]> flush privileges;
Query OK, 0 rows affected (0.00 sec)

4、演示FEDERATED存储引擎跨实例访问

[root@rhel64a ~]# mysql -uroot -pxxx

root@localhost[(none)]> show variables like 'version';
+---------------+--------+
| Variable_name | Value  |
+---------------+--------+
| version       | 5.6.21 |
+---------------+--------+

#查看是否支持FEDERATED引擎
root@localhost[(none)]> select * from information_schema.engines where engine='federated';
+-----------+---------+--------------------------------+--------------+------+------------+
| ENGINE    | SUPPORT | COMMENT                        | TRANSACTIONS | XA   | SAVEPOINTS |
+-----------+---------+--------------------------------+--------------+------+------------+
| FEDERATED | NO      | Federated MySQL storage engine | NULL         | NULL | NULL       |
+-----------+---------+--------------------------------+--------------+------+------------+

root@localhost[(none)]> exit
[root@rhel64a ~]# service mysql stop
Shutting down MySQL..[  OK  ]
#配置启用FEDERATED引擎
[root@rhel64a ~]# vi /etc/my.cnf
[root@rhel64a ~]# tail -7 /etc/my.cnf
[mysqld]
socket = /tmp/mysql3306.sock
port = 3306
pid-file = /var/lib/mysql/my3306.pid
user = mysql
server-id=3306/
federated         #添加该选项
[root@rhel64a ~]# service mysql start
Starting MySQL.[  OK  ]
[root@rhel64a ~]# mysql -uroot -pxxx
root@localhost[(none)]> select * from information_schema.engines where engine='federated';
+-----------+---------+--------------------------------+--------------+------+------------+
| ENGINE    | SUPPORT | COMMENT                        | TRANSACTIONS | XA   | SAVEPOINTS |
+-----------+---------+--------------------------------+--------------+------+------------+
| FEDERATED | YES     | Federated MySQL storage engine | NO           | NO   | NO         |
+-----------+---------+--------------------------------+--------------+------+------------+

root@localhost[(none)]> use test

-- 创建基于FEDERATED引擎的表federated_engine
root@localhost[test]> CREATE TABLE `federated_engine` (
    ->   `engine` varchar(64) NOT NULL DEFAULT '',
    ->   `support` varchar(8) NOT NULL DEFAULT '',
    ->   `comment` varchar(80) NOT NULL DEFAULT ''
    -> ) ENGINE=FEDERATED DEFAULT CHARSET=utf8
    -> CONNECTION='mysql://remote_user:xxx@192.168.1.131:3406/tempdb/tb_engine';
Query OK, 0 rows affected (0.00 sec)

-- 下面是创建后表格式文件
root@localhost[test]> system ls -hltr /var/lib/mysql/test
total 12K
-rw-rw---- 1 mysql mysql 8.5K Oct 24 08:22 federated_engine.frm

--查询表federated_engine
root@localhost[test]> select * from federated_engine limit 2;
+------------+---------+---------------------------------------+
| engine     | support | comment                               |
+------------+---------+---------------------------------------+
| MRG_MYISAM | YES     | Collection of identical MyISAM tables |
| CSV        | YES     | CSV storage engine                    |
+------------+---------+---------------------------------------+

--更新表federated_engine
root@localhost[test]> update federated_engine set support='NO' where engine='CSV';
Query OK, 1 row affected (0.03 sec)
Rows matched: 1  Changed: 1  Warnings: 0

--查看更新后的结果
root@localhost[test]> select * from federated_engine where engine='CSV';
+--------+---------+--------------------+
| engine | support | comment            |
+--------+---------+--------------------+
| CSV    | NO      | CSV storage engine |
+--------+---------+--------------------+

5、创建FEDERATED引擎表的链接方式

scheme: A recognized connection protocol. Only mysql is supported as the scheme value at this point.

链接示例样本:

6、涉及到的相关参考