在mysql 5.7 中如何开启半同步复制

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)

set global rpl_semi_sync_master_enabled=1;  set global rpl_semi_sync_master_timeout=1000;  set global rpl_semi_sync_slave_enabled=1;

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

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%';

stop slave io_thread;  start slave io_thread;

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 statusG;  *************************** 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

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)

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%';

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;