MySQL - FEDERATED引擎實現跨服務器查詢

1. MySQL插件的安裝與卸載

# 查看插件信息
mysql> show plugins;
mysql> select plugin_name,plugin_status,plugin_library,plugin_description from information_schema.plugins;

# 查看插件共享庫位置
mysql> show variables like 'plugin_dir';
+-----------------+---------------------------+
| Variable_name   | Value                     |
+-----------------+---------------------------+
| plugin_dir      |/usr/lib64/mysql/plugin/   |
+-----------------+---------------------------+

# 安裝插件
install plugin PLUGIN_NAME soname 'SHARTED_LIBRARY_NAME.so'

# 卸載插件
uninstall plugin PLUGIN_NAME

# 開啟/關閉插件
$ vim /etc/my.cnf
[mysqld]
PLUGIN_NAME = ON|OFF

 

2. 激活FEDERATED插件，並創建垮服務器數據庫表

　　FEDERATED存儲引擎訪問在遠程數據庫的表中的數據，而不是本地的表。這個特性給某些開發應用帶來了便利，你可以直接在本地構建一個FEDERATED表來連接遠程數據表，配置好了之后本地表的數據可以直接跟遠程數據表同步。實際上這個引擎里面是不真實存放數據的，所需要的數據都是連接到其他MySQL服務器上。

2.1 查看FEDERATED引擎是否開啟

# 方法1：查看插件,ACTIVE為開啟，DISABLED為未開啟
> show plugins;
+--------------------------------+----------+--------------------+--------------------+---------+
| Name                           | Status   | Type               | Library            | License |
+--------------------------------+----------+--------------------+--------------------+---------+
| binlog                         | ACTIVE   | STORAGE ENGINE     | NULL               | GPL     |
| FEDERATED                      | DISABLED | STORAGE ENGINE     | NULL               | GPL     |
| rpl_semi_sync_master           | ACTIVE   | REPLICATION        | semisync_master.so | GPL     |
+--------------------------------+----------+--------------------+--------------------+---------+
# 方法2：查看引擎，YES為開啟，NO為未開啟
mysql> show engines;
+--------------------+---------+----------------------------------------------------------------------------+--------------+------+------------+
| Engine             | Support | Comment                                                                    | Transactions | XA   | Savepoints |
+--------------------+---------+----------------------------------------------------------------------------+--------------+------+------------+
| CSV                | YES     | CSV storage engine                                                         | NO           | NO   | NO         |
| 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         |
| InnoDB             | DEFAULT | Percona-XtraDB, Supports transactions, row-level locking, and foreign keys | YES          | YES  | YES        |
| ARCHIVE            | YES     | Archive storage engine                                                     | NO           | NO   | NO         |
| FEDERATED          | NO      | FederatedX pluggable storage engine                                        | NULL         | NULL | NULL       |
| PERFORMANCE_SCHEMA | YES     | Performance Schema                                                         | NO           | NO   | NO         |
| Aria               | YES     | Crash-safe tables with MyISAM heritage                                     | NO           | NO   | NO         |
+--------------------+---------+----------------------------------------------------------------------------+--------------+------+------------+

 

2.2 開啟FEDERATED插件

# MySQL配置文件中添加federated[=ON]，然后重啟MySQL服務
$ vim /etc/my.cnf
[mysqld]
federated=ON

$ systemctl restart mariadb

 

 2.3 創建一張虛擬表，此表鏈接到另外一台服務器數據庫上的表中

# 創建數據庫
mysql> CREATE DATABASE DB_NAME DEFAULT CHARSET utf8;

# 創建表
# USER:數據庫賬號，PASSWD：數據庫密碼，HOST：遠程數據庫連接地址，PORT：端口，DB_NAME：數據庫名，TB_NAME：表名
mysql> USE DB_NAME;
mysql> CREATE TABLE TABLE_NAME (
    ...
) ENGINE=FEDERATED DEFAULT CHARSET=utf8 CONNECTION='mysql://USER:PASSWD@HOST:PORT/DB_NAME/TABLE_NAME'

 

2.4 注意事項

　　1. 對本地虛擬表的結構修改，並不會修改遠程表的結構 
　　2.truncate 命令，會清除遠程表數據 
　　3.  drop命令只會刪除虛擬表，並不會刪除遠程表