MySQL半同步复制的安装和配置

(1)检查master/slave是否支持动态加载插件

> show variables like 'have_dynamic_loading';
+----------------------+-------+
| Variable_name        | Value |
+----------------------+-------+
| have_dynamic_loading | YES   |
+----------------------+-------+

(2)检查plugin_dir位置，插件的放置位置

> show variables like '%plugin_dir%';
+---------------+------------------------------+
| Variable_name | Value                        |
+---------------+------------------------------+
| plugin_dir    | /usr/local/mysql/lib/plugin/ |
+---------------+------------------------------+

(3)在master端执行

> install plugin rpl_semi_sync_master soname 'semisync_master.so';
> show pluginsG
*************************** 43. row ***************************
   Name: rpl_semi_sync_master
 Status: ACTIVE
   Type: REPLICATION
Library: semisync_master.so
License: GPL
43 rows in set (0.00 sec)

>select plugin_name,plugin_status from information_schema.plugins where plugin_name like '%semi%';
+----------------------+---------------+
| plugin_name          | plugin_status |
+----------------------+---------------+
| rpl_semi_sync_master | ACTIVE        |
+----------------------+---------------+

(4)在slave端执行

> install plugin rpl_semi_sync_slave soname 'semisync_slave.so';
> show pluginsG
*************************** 43. row ***************************
   Name: rpl_semi_sync_master
 Status: ACTIVE
   Type: REPLICATION
Library: semisync_master.so
License: GPL
43 rows in set (0.00 sec)

>select plugin_name,plugin_status from information_schema.plugins where plugin_name like '%semi%';
+----------------------+---------------+
| plugin_name          | plugin_status |
+----------------------+---------------+
| rpl_semi_sync_master | ACTIVE        |
+----------------------+---------------+

(5)master开启半同步复制

> set global rpl_semi_sync_master_enabled=1;
> set global rpl_semi_sync_master_timeout=30;
>show global variables like 'rpl_semi_sync_master_enabled';
+------------------------------+-------+
| Variable_name                | Value |
+------------------------------+-------+
| rpl_semi_sync_master_enabled | ON    |
+------------------------------+-------+

(6)slave开启半同步复制

> set global rpl_semi_sync_slave_enabled=1;
> show global variables like 'rpl_semi_sync_slave_enabled';
+-----------------------------+-------+
| Variable_name               | Value |
+-----------------------------+-------+
| rpl_semi_sync_slave_enabled | ON    |
+-----------------------------+-------+

(7)如果slave在运行状态，要重启io_thread

> stop slave io_thread;
> start slave io_thread;

(8)把配置信息写入配置文件

master端：
[mysqld]
rpl_semi_sync_master_enabled=1
rpl_semi_sync_master_timeout=1000 # 1 second

slave端: 
[mysqld]
rpl_semi_sync_slave_enabled=1