LNMP架构（11）mysql的半同步复制原理及配置

server2:主机的配置
mysql -p 
mysql> INSTALL PLUGIN rpl_semi_sync_master SONAME 'semisync_master.so';
Query OK, 0 rows affected (0.02 sec)

mysql> show variables like 'rpl%';
+-------------------------------------------+------------+
| Variable_name                             | Value      |
+-------------------------------------------+------------+
| rpl_read_size                             | 8192       |
| rpl_semi_sync_master_enabled              | OFF        |
| rpl_semi_sync_master_timeout              | 10000      |
| rpl_semi_sync_master_trace_level          | 32         |
| rpl_semi_sync_master_wait_for_slave_count | 1          |
| rpl_semi_sync_master_wait_no_slave        | ON         |
| rpl_semi_sync_master_wait_point           | AFTER_SYNC |
| rpl_stop_slave_timeout                    | 31536000   |
+-------------------------------------------+------------+
8 rows in set (0.01 sec)
mysql> SET GLOBAL rpl_semi_sync_master_timeout = 10000;
Query OK, 0 rows affected (0.00 sec)

mysql> show variables like 'rpl%';
+-------------------------------------------+------------+
| Variable_name                             | Value      |
+-------------------------------------------+------------+
| rpl_read_size                             | 8192       |
| rpl_semi_sync_master_enabled              | ON         |
| rpl_semi_sync_master_timeout              | 10000      |
| rpl_semi_sync_master_trace_level          | 32         |
| rpl_semi_sync_master_wait_for_slave_count | 1          |
| rpl_semi_sync_master_wait_no_slave        | ON         |
| rpl_semi_sync_master_wait_point           | AFTER_SYNC |
| rpl_stop_slave_timeout                    | 31536000   |
+-------------------------------------------+------------+
8 rows in set (0.00 sec)
mysql> SHOW PLUGINS;
 INNODB_SESSION_TEMP_TABLESPACES | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
mysql> create database test;
Query OK, 1 row affected (10.01 sec)
mysql> insert into test.user_tb value('user1',111);
Query OK, 1 row affected (0.01 sec)
mysql> insert into test.user_tb value('user2',111);
Query OK, 1 row affected (0.00 sec)

slave的配置

mysql> show variables like 'rpl%';
+---------------------------------+----------+
| Variable_name                   | Value    |
+---------------------------------+----------+
| rpl_read_size                   | 8192     |
| rpl_semi_sync_slave_enabled     | OFF      |
| rpl_semi_sync_slave_trace_level | 32       |
| rpl_stop_slave_timeout          | 31536000 |
+---------------------------------+----------+
4 rows in set (0.01 sec)

mysql> SET GLOBAL rpl_semi_sync_slave_enabled = 1;
Query OK, 0 rows affected (0.00 sec)

mysql> show variables like 'rpl%';
+---------------------------------+----------+
| Variable_name                   | Value    |
+---------------------------------+----------+
| rpl_read_size                   | 8192     |
| rpl_semi_sync_slave_enabled     | ON       |
| rpl_semi_sync_slave_trace_level | 32       |
| rpl_stop_slave_timeout          | 31536000 |
+---------------------------------+----------+
4 rows in set (0.01 sec)

测试：slave没开启时 在master上测试

mysql> show status like 'rpl%';
+--------------------------------------------+-------+
| Variable_name                              | Value |
+--------------------------------------------+-------+
| Rpl_semi_sync_master_clients               | 1     |
| Rpl_semi_sync_master_net_avg_wait_time     | 0     |
| Rpl_semi_sync_master_net_wait_time         | 0     |
| Rpl_semi_sync_master_net_waits             | 0     |
| Rpl_semi_sync_master_no_times              | 1     |
| Rpl_semi_sync_master_no_tx                 | 4     |同步失败
| Rpl_semi_sync_master_status                | ON    |
| Rpl_semi_sync_master_timefunc_failures     | 0     |
| Rpl_semi_sync_master_tx_avg_wait_time      | 0     |
| Rpl_semi_sync_master_tx_wait_time          | 0     |
| Rpl_semi_sync_master_tx_waits              | 0     |
| Rpl_semi_sync_master_wait_pos_backtraverse | 0     |
| Rpl_semi_sync_master_wait_sessions         | 0     |
| Rpl_semi_sync_master_yes_tx                | 0     |
+--------------------------------------------+-------+
14 rows in set (0.00 sec)
# 结果显示有四条sql语句没有同步过去，因为在slave上没有开启io 线程。

开启之后 在主机上插入一条语句，

mysql> STOP SLAVE IO_THREAD;

mysql> START SLAVE IO_THREAD;

mysql> show status like 'rpl%';
+--------------------------------------------+-------+
| Variable_name                              | Value |
+--------------------------------------------+-------+
| Rpl_semi_sync_master_clients               | 1     |
| Rpl_semi_sync_master_net_avg_wait_time     | 0     |
| Rpl_semi_sync_master_net_wait_time         | 0     |
| Rpl_semi_sync_master_net_waits             | 1     |
| Rpl_semi_sync_master_no_times              | 1     |
| Rpl_semi_sync_master_no_tx                 | 4     |之前的同步失败
| Rpl_semi_sync_master_status                | ON    |
| Rpl_semi_sync_master_timefunc_failures     | 0     |
| Rpl_semi_sync_master_tx_avg_wait_time      | 442   |
| Rpl_semi_sync_master_tx_wait_time          | 442   |
| Rpl_semi_sync_master_tx_waits              | 1     |
| Rpl_semi_sync_master_wait_pos_backtraverse | 0     |
| Rpl_semi_sync_master_wait_sessions         | 0     |
| Rpl_semi_sync_master_yes_tx                | 1     | #表示同步成功
+--------------------------------------------+-------+
14 rows in set (0.00 sec)