MySQL 5.6.x半同步复制配置

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本文环境
主库：CentOS6.5 x64 192.168.0.65 MySQL-5.6.29
备库：CentOS6.5 x64 192.168.0.66 mysql-5.6.29

接上文: MySQL 5.6 主从同步配置案例 http://www.linuxidc.com/Linux/2016-04/130729.htm

半同步复制的概念:
mysql5.5.x 以上版本支持半同步复制，当 Slave 主机连接到 Master 时，能够查看其是否处于半同步复制的机制。当 Master 上开启半同步复制的功能时，至少应该有一个 Slave 开启其功能。此时，一个线程在 Master 上提交事务将受到阻塞，直到得知一个已开启半同步复制功能的 Slave 已收到此事务的所有事件，或等待超时。当一个事务的事件都已写入其 relay-log 中且已刷新到磁盘上，Slave 才会告知已收到。如果等待超时，也就是 Master 没被告知已收到，此时 Master 会自动转换为异步复制的机制。当至少一个半同步的 Slave 赶上了，Master 与其 Slave 自动转换为半同步复制的机制。半同步复制的功能要在 Master，Slave 都开启，半同步复制才会起作用；否则，只开启一边，它依然为异步复制。

# vi /etc/my.cnf

[mysqld]
log-bin = master-bin
log-bin-index = master-bin.index
binlog_format = mixed
server-id = 1
expire-logs-days = 7
rpl_semi_sync_master_enabled = 1
rpl_semi_sync_master_timeout = 1000 # 1 second

mysql> install plugin rpl_semi_sync_master soname ‘semisync_master.so’;

mysql> show global variables like ‘%rpl%’;
+————————————+——-+
| Variable_name | Value |
+————————————+——-+
| rpl_recovery_rank | 0 |
| rpl_semi_sync_master_enabled | OFF |
| rpl_semi_sync_master_timeout | 10000 |
| rpl_semi_sync_master_trace_level | 32 |
| rpl_semi_sync_master_wait_no_slave | ON |
+————————————+——-+

mysql> set global rpl_semi_sync_master_enabled =1;

mysql> set rpl_semi_sync_master_timeout 1000;

mysql> show global status like ‘rpl_semi%’;
+——————————————–+——-+
| Variable_name | Value |
+——————————————–+——-+
| Rpl_semi_sync_master_clients | 0 |
| 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 | 0 |
| Rpl_semi_sync_master_no_tx | 0 |
| 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)

其它一些性能及相关参数：

# service mysqld restart

# vi /etc/my.cnf

[mysqld]
log-bin = mysql-bin
binlog_format = mixed
server-id = 11
relay-log = slave-relay-bin
relay-log-index = slave-relay-bin.index
replicate_wild_ignore_table = mysql.%
rpl_semi_sync_slave_enabled = 1

mysql> install plugin rpl_semi_sync_slave soname ‘semisync_slave.so’;
Query OK, 0 rows affected (0.00 sec)

mysql> set global rpl_semi_sync_master_enabled =1;
Query OK, 0 rows affected (0.00 sec)

mysql> stop slave;
Query OK, 0 rows affected (0.02 sec)

mysql> start slave;
Query OK, 0 rows affected (0.02 sec)

mysql> show slave status \G;
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.0.65
Master_User: repl
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: master-bin.000005
Read_Master_Log_Pos: 120
Relay_Log_File: testdb-relay-bin.000012
Relay_Log_Pos: 284
Relay_Master_Log_File: master-bin.000005
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: mysql.%
Last_Errno: 0
Last_Error:
Skip_Counter: 0
Exec_Master_Log_Pos: 120
Relay_Log_Space: 622
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: 1
Master_UUID: c8bb22a1-024e-11e6-a1e8-000c29225fa0
Master_Info_File: /usr/local/mysql-5.6.29-linux-glibc2.5-x86_64/data/master.info
SQL_Delay: 0
SQL_Remaining_Delay: NULL
Slave_SQL_Running_State: Slave has read all relay log; waiting for the slave I/O thread to update it
Master_Retry_Count: 86400
Master_Bind:
Last_IO_Error_Timestamp:
Last_SQL_Error_Timestamp:
Master_SSL_Crl:
Master_SSL_Crlpath:
Retrieved_Gtid_Set:
Executed_Gtid_Set:
Auto_Position: 0
1 row in set (0.00 sec)

mysql> show global status like ‘rpl_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 | 0 |
| Rpl_semi_sync_master_no_times | 0 |
| Rpl_semi_sync_master_no_tx | 0 |
| 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)