mysql-5.6.x半同步复制配置

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

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 

log-bin                = mysql-bin    

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)

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

| variable_name                   | value    |    

| rpl_semi_sync_slave_enabled     | on       |    

| rpl_semi_sync_slave_trace_level | 32       |    

| rpl_stop_slave_timeout          | 31536000 |    

3 rows in set (0.00 sec)

mysql> set global rpl_semi_sync_master_enabled =1;   

mysql> stop slave;   

query ok, 0 rows affected (0.02 sec)

mysql> start slave;   

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)

| rpl_semi_sync_master_clients               | 1     |