MySQL master-slave synchronization enables semi-sync

To install the MySQL semi-sync plugin:
Primary Server Installation Plugin:
Mysql> show global variables like ' plugin_dir% ';
+---------------+--------------------------+
| variable_name | Value |
+---------------+--------------------------+
| Plugin_dir | /usr/lib64/mysql/plugin/| The exact location of the current MySQL plug-in directory
+---------------+--------------------------+

MySQL > INSTALL PLUGIN rpl_semi_sync_master SONAME ' semisync_master.so ';
Master server semi-synchronous parameters (only after plug-in installation):
Mysql> show global variables like ' rpl_semi_sync_master% ';
+-------------------------------------------+------------+
| variable_name | Value |
+-------------------------------------------+------------+
| rpl_semi_sync_master_enabled | OFF | Turn on semi-synchronous mode
| Rpl_semi_sync_master_timeout | 10000 | Half-sync Timeout time 10000 ms
| Rpl_semi_sync_master_trace_level | 32 | Trace level
| Rpl_semi_sync_master_wait_for_slave_count | 1 | Wait at least how many servers to complete synchronization from the server
| Rpl_semi_sync_master_wait_no_slave | On |
| Rpl_semi_sync_master_wait_point | After_sync | 5.7 New semi-synchronous mode (Value=after_sync is loss-less semi-synchronous, After_commit is the old half-sync)
+-------------------------------------------+------------+

Turn on the master server semi-synchronous:mysql> set global rpl_semi_sync_master_enabled=on; Install the plugin from the server:

MySQL > INSTALL PLUGIN rpl_semi_sync_slave SONAME ' semisync_slave.so ';
Semi-sync parameters from the server (only after the plug-in is installed):
Mysql> show global variables like ' rpl_semi_sync_slave% ';
+---------------------------------+-------+
| variable_name | Value |
+---------------------------------+-------+
| rpl_semi_sync_slave_enabled | OFF | Turn on semi-synchronous mode
| Rpl_semi_sync_slave_trace_level | 32 | Trace level
+---------------------------------+-------+
Open the:mysql> set global rpl_semi_sync_slave_enabled=on from the server boot half-sync;

To view specific half-sync status information:
Main:
MySQL > Show global status Like ' rpl_semi_sync% ';
+--------------------------------------------+-------+
| variable_name | Value |
+--------------------------------------------+-------+
| rpl_semi_sync_master_clients | 0 | Number of semi-synchronous copies from the server
| Rpl_semi_sync_master_net_avg_wait_time | 0 | Average Network wait time
| Rpl_semi_sync_master_net_wait_time | 0 | Network wait duration
| Rpl_semi_sync_master_net_waits | 0 |
| Rpl_semi_sync_master_no_times | 0 |
| Rpl_semi_sync_master_no_tx | 0 |
| Rpl_semi_sync_master_status | On | Primary server semi-synchronous state
| 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 |
+--------------------------------------------+-------+

Note: This requires a reboot from the server's thread, which has previously been stuck in the semi-synchronous, State (Rpl_semi_sync_master_status=on), but not from the client (rpl_semi_sync_master_clients= 0), see the status information above
mysql> STOP SLAVE [Io_thread];
mysql> START SLAVE [Io_thread];

MySQL master-slave synchronization enables semi-sync