1.安装相关的插件show plugins; 查看模块

help --uninstall; 查看卸载模块master:

mysql> install plugin rpl_semi_sync_master soname 'semisync_master.so'; --安装 semisync_master.so插件

Query OK, 0 rows affected (0.03 sec)

slave:

root@localhost [zw3306]>install plugin rpl_semi_sync_slave soname 'semisync_slave.so'; --安装 semisync_slave.so插件

Query OK, 0 rows affected (0.00 sec)

root@localhost [zw3306]>install plugin rpl_semi_sync_master soname 'semisync_master.so';

Query OK, 0 rows affected (0.00 sec)

2.修改的参数：set global rpl_semi_sync_master_enabled=1;

set global rpl_semi_sync_master_timeout=1000;

set global rpl_semi_sync_slave_enabled=1;

也可以直接写到配置文件 [mysqld]master:

[mysqld]

rpl_semi_sync_master_enabled = 1

rpl_semi_sync_master_timeout = 1000 # 1 second

slave：

[mysqld]

rpl_semi_sync_slave_enabled = 1

修改了参数需要重启：

查看修改的参数master:

mysql> show global variables like '%rpl_semi%';+-------------------------------------------+------------+

| Variable_name | Value |

+-------------------------------------------+------------+

| rpl_semi_sync_master_enabled | ON |

| rpl_semi_sync_master_timeout | 1000 |

| 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 |

+-------------------------------------------+------------+

6 rows in set (0.00 sec)

slave:

root@localhost [(none)]>show global variables like '%rpl_semi%';+-------------------------------------------+------------+

| Variable_name | Value |

+-------------------------------------------+------------+

| rpl_semi_sync_master_enabled | ON |

| rpl_semi_sync_master_timeout | 1000 |

| 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_semi_sync_slave_enabled | ON |

| rpl_semi_sync_slave_trace_level | 32 |

+-------------------------------------------+------------+

8 rows in set (0.00 sec)

如果：如果原来是已经建好的复制结构很简单：stop slave io_thread;

start slave io_thread;

3.做同步change master to master_host='192.168.26.233', master_port=3306, master_user='repl',master_password='repl', master_auto_position=1;

root@localhost [(none)]>start slave;

Query OK, 0 rows affected (0.01 sec)

root@localhost [(none)]>show slave status\G;

*************************** 1. row ***************************

Slave_IO_State: Waiting for master to send event

Master_Host: 192.168.26.233

Master_User: repl

Master_Port: 3306

Connect_Retry: 60

Master_Log_File: mysql-bin.000002

Read_Master_Log_Pos: 194

Relay_Log_File: relay-bin.000004

Relay_Log_Pos: 407

Relay_Master_Log_File: mysql-bin.000002

Slave_IO_Running: Yes

Slave_SQL_Running: Yes

Replicate_Do_DB:

Replicate_Ignore_DB:

Replicate_Do_Table:

Replicate_Ignore_Table:

Replicate_Wild_Do_Table:

Replicate_Wild_Ignore_Table:

Last_Errno: 0

Last_Error:

Skip_Counter: 0

Exec_Master_Log_Pos: 194

Relay_Log_Space: 861

Until_Condition: None

Until_Log_File:

Until_Log_Pos: 0

Master_SSL_Allowed: No

Master_SSL_CA_File:

Master_SSL_CA_Path:

Master_SSL_Cert:

Master_SSL_Cipher:

Master_SSL_Key:

Seconds_Behind_Master: 0

Master_SSL_Verify_Server_Cert: No

Last_IO_Errno: 0

Last_IO_Error:

Last_SQL_Errno: 0

Last_SQL_Error:

Replicate_Ignore_Server_Ids:

Master_Server_Id: 3306100

Master_UUID: 7e354a2c-6f5f-11e6-997d-005056a36f08

Master_Info_File: mysql.slave_master_info

SQL_Delay: 0

SQL_Remaining_Delay: NULL

Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates

Master_Retry_Count: 86400

Master_Bind:

Last_IO_Error_Timestamp:

Last_SQL_Error_Timestamp:

Master_SSL_Crl:

Master_SSL_Crlpath:

Retrieved_Gtid_Set: 7e354a2c-6f5f-11e6-997d-005056a36f08:1-9

Executed_Gtid_Set: 7e354a2c-6f5f-11e6-997d-005056a36f08:1-9,

ba0d5587-74d6-11e6-ab5c-005056a3f46e:1-2

Auto_Position: 1

Replicate_Rewrite_DB:

Channel_Name:

Master_TLS_Version:

1 row in set (0.00 sec)

ERROR:

No query specified

5.查看slave是否有数据root@localhost [zw3306]>show tables;

+------------------+

| Tables_in_zw3306 |

+------------------+

| t1 |

+------------------+

1 row in set (0.00 sec)

root@localhost [zw3306]>select * from t1;+------+

| id |

+------+

| 1 |

| 2 |

| 3 |

| 4 |

+------+

4 rows in set (0.00 sec)

6. 怎么确认是同步还是半同步？show global variables like '%semi%';

show global status like '%semi%';master:

root@localhost [zw3306]>show global status like '%semi%';+--------------------------------------------+-------+

| Variable_name | Value |

+--------------------------------------------+-------+

| Rpl_semi_sync_master_clients | 1 | 有多少个Semi-sync的备库

| Rpl_semi_sync_master_net_avg_wait_time | 0 | 事务提交后，等待备库响应的平均时间

| Rpl_semi_sync_master_net_wait_time | 0 | 等待网络响应的总次数

| Rpl_semi_sync_master_net_waits | 7 | 总的网络等待时间

| Rpl_semi_sync_master_no_times | 0 | 一共有几次从Semi-sync跌回普通状态

| Rpl_semi_sync_master_no_tx | 0 | 库未及时响应的事务数,如果这个值很大就有问题

| Rpl_semi_sync_master_status | ON | 主库上Semi-sync是否正常开启

| Rpl_semi_sync_master_timefunc_failures | 0 | 时间函数未正常工作的次数

| Rpl_semi_sync_master_tx_avg_wait_time | 410 | 开启Semi-sync，事务返回需要等待的平均时间

| Rpl_semi_sync_master_tx_wait_time | 2876 | 事务等待备库响应的总时间

| Rpl_semi_sync_master_tx_waits | 7 | 事务等待备库响应的总次数

| Rpl_semi_sync_master_wait_pos_backtraverse | 0 | 改变当前等待最小二进制日志的次数

| Rpl_semi_sync_master_wait_sessions | 0 | 当前有几个线程在等备库响应

| Rpl_semi_sync_master_yes_tx | 7 | Semi-sync模式下，成功的事务数

+--------------------------------------------+-------+

15 rows in set (0.00 sec)

root@localhost [zw3306]>show global variables like '%semi%';+-------------------------------------------+------------+

| Variable_name | Value |

+-------------------------------------------+------------+

| rpl_semi_sync_master_enabled | ON |

| rpl_semi_sync_master_timeout | 1000 |

| 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_semi_sync_slave_enabled | ON |

| rpl_semi_sync_slave_trace_level | 32 |

+-------------------------------------------+------------+

8 rows in set (0.00 sec)

Rpl_semi_sync_master_no_tx如果这个值很大就有问题

也有其他的原因；mysql> show global status like '%semi%';+--------------------------------------------+-------+

| 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 | 17 |

| Rpl_semi_sync_master_no_times | 1 |

| Rpl_semi_sync_master_no_tx | 10 | 不是用半同步复制的

| Rpl_semi_sync_master_status | OFF |

| Rpl_semi_sync_master_timefunc_failures | 0 |

| Rpl_semi_sync_master_tx_avg_wait_time | 410 |

| Rpl_semi_sync_master_tx_wait_time | 2876 |

| Rpl_semi_sync_master_tx_waits | 7 |

| Rpl_semi_sync_master_wait_pos_backtraverse | 0 |

| Rpl_semi_sync_master_wait_sessions | 0 |

| Rpl_semi_sync_master_yes_tx | 7 |

+--------------------------------------------+-------+

14 rows in set (0.01 sec)

操作10个事物，可以发现都是 Rpl_semi_sync_master_no_tx

master接收到N个slave的应答后，才commit事物，等待1s用户可以设置应道slave的数量。

rpl_semi_sync_master_wait_for_slave_count=1 默认是1

set global rpl_semi_sync_master_wait_for_slave_count=2;

意思是多少个半同步的slave;