MySQL HA的全新篇章：Semisynchronous Replication迁移至InnoDB Cluster的实用指南

1、概述

临时接了一个搭建InnoDB Cluster的活儿，客户给我说是有数据的，我当时想这不是非常简单吗？干活儿的时候，才发现并没有这么简单，接手的时候发现是Semisynchronous Replication的环境，然后把从库切换成InnoDB Cluster的primary。

2、环境复现

2.1、从库5.140信息采集

mysql> show replica status\G
*************************** 1. row ***************************
             Replica_IO_State: Waiting for source to send event
                  Source_Host: 192.168.5.130
                  Source_User: repuser
                  Source_Port: 3306
                Connect_Retry: 60
              Source_Log_File: mydb-binlog.000001
          Read_Source_Log_Pos: 342
               Relay_Log_File: mydb-relay.000002
                Relay_Log_Pos: 562
        Relay_Source_Log_File: mydb-binlog.000001
           Replica_IO_Running: Yes
          Replica_SQL_Running: Yes
...
1 row in set (0.00 sec)


mysql> select PLUGIN_NAME,PLUGIN_STATUS from information_schema.plugins where plugin_name like '%semi%';
+----------------------+---------------+
| PLUGIN_NAME          | PLUGIN_STATUS |
+----------------------+---------------+
| rpl_semi_sync_master | ACTIVE        |
| rpl_semi_sync_slave  | ACTIVE        |
+----------------------+---------------+
2 rows in set (0.00 sec)

mysql>
mysql>
mysql> show variables like '%semi_sync%';
+-------------------------------------------+------------+
| Variable_name                             | Value      |
+-------------------------------------------+------------+
| rpl_semi_sync_master_enabled              | ON         |
| rpl_semi_sync_master_timeout              | 5000       |
| 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)

mysql>
mysql>
mysql> show plugins;
+----------------------------------+----------+--------------------+--------------------+---------+
| Name                             | Status   | Type               | Library            | License |
+----------------------------------+----------+--------------------+--------------------+---------+
...
| rpl_semi_sync_master             | ACTIVE   | REPLICATION        | semisync_master.so | GPL     |
| rpl_semi_sync_slave              | ACTIVE   | REPLICATION        | semisync_slave.so  | GPL     |
+----------------------------------+----------+--------------------+--------------------+---------+
50 rows in set (0.00 sec)

mysql> select PLUGIN_NAME,PLUGIN_STATUS from information_schema.plugins where plugin_name like '%semi%';
+----------------------+---------------+
| PLUGIN_NAME          | PLUGIN_STATUS |
+----------------------+---------------+
| rpl_semi_sync_master | ACTIVE        |
| rpl_semi_sync_slave  | ACTIVE        |
+----------------------+---------------+
2 rows in set (0.00 sec)

2.2、从库5.140 InnoDB Cluster准备工作

mysql> stop replica;
Query OK, 0 rows affected (0.00 sec)


mysql> show replica status\G
*************************** 1. row ***************