【MySQL】MySQL5.7半同步配置

前言:在MySQL主从复制中分为异步复制及半同步复制,不像Oracle分为最大性能模式,最大可用模式,最大保护模式。相比较而言,MySQL的复制更加简单一些,并且基本所有的MySQL高可用方案都是基于主从复制来做的。一般的传统复制即异步复制,主库上的事务无需等待从库应答即可提交。而半同步复制需要从库接收binlog并向主应答,这又分为after sync和after commit两种模式,具体两种区别可以参考之前的文章【MySQL】5.7增强半同步AFTER SYNC&AFTER COMMIT
这里以MySQL5.7为例讲一下怎么怎么搭建半主从复制。

一、安装半同步插件

  • Master
    查看当前所有已安装的插件:
root@localhost [(none)]>show plugins;
ERROR 2006 (HY000): MySQL server has gone away
No connection. Trying to reconnect...
Connection id:    6
Current database: *** NONE ***

+----------------------------+----------+--------------------+---------+---------+
| Name                       | Status   | Type               | Library | License |
+----------------------------+----------+--------------------+---------+---------+
| binlog                     | ACTIVE   | STORAGE ENGINE     | NULL    | GPL     |
| mysql_native_password      | ACTIVE   | AUTHENTICATION     | NULL    | GPL     |
| sha256_password            | ACTIVE   | AUTHENTICATION     | NULL    | GPL     |
| PERFORMANCE_SCHEMA         | ACTIVE   | STORAGE ENGINE     | NULL    | GPL     |
| MRG_MYISAM                 | ACTIVE   | STORAGE ENGINE     | NULL    | GPL     |
| MEMORY                     | ACTIVE   | STORAGE ENGINE     | NULL    | GPL     |
| InnoDB                     | ACTIVE   | STORAGE ENGINE     | NULL    | GPL     |
| INNODB_TRX                 | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |
| INNODB_LOCKS               | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |
| INNODB_LOCK_WAITS          | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |
| INNODB_CMP                 | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |
| INNODB_CMP_RESET           | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |
| INNODB_CMPMEM              | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |
| INNODB_CMPMEM_RESET        | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |
| INNODB_CMP_PER_INDEX       | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |
| INNODB_CMP_PER_INDEX_RESET | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |
| INNODB_BUFFER_PAGE         | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |
| INNODB_BUFFER_PAGE_LRU     | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |
| INNODB_BUFFER_POOL_STATS   | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |
| INNODB_TEMP_TABLE_INFO     | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |
| INNODB_METRICS             | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |
| INNODB_FT_DEFAULT_STOPWORD | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |
| INNODB_FT_DELETED          | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |
| INNODB_FT_BEING_DELETED    | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |
| INNODB_FT_CONFIG           | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |
| INNODB_FT_INDEX_CACHE      | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |
| INNODB_FT_INDEX_TABLE      | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |
| INNODB_SYS_TABLES          | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |
| INNODB_SYS_TABLESTATS      | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |
| INNODB_SYS_INDEXES         | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |
| INNODB_SYS_COLUMNS         | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |
| INNODB_SYS_FIELDS          | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |
| INNODB_SYS_FOREIGN         | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |
| INNODB_SYS_FOREIGN_COLS    | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |
| INNODB_SYS_TABLESPACES     | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |
| INNODB_SYS_DATAFILES       | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |
| INNODB_SYS_VIRTUAL         | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |
| CSV                        | ACTIVE   | STORAGE ENGINE     | NULL    | GPL     |
| MyISAM                     | ACTIVE   | STORAGE ENGINE     | NULL    | GPL     |
| ARCHIVE                    | ACTIVE   | STORAGE ENGINE     | NULL    | GPL     |
| partition                  | ACTIVE   | STORAGE ENGINE     | NULL    | GPL     |
| BLACKHOLE                  | ACTIVE   | STORAGE ENGINE     | NULL    | GPL     |
| FEDERATED                  | DISABLED | STORAGE ENGINE     | NULL    | GPL     |
| ngram                      | ACTIVE   | FTPARSER           | NULL    | GPL     |
+----------------------------+----------+--------------------+---------+---------+
44 rows in set (0.00 sec)

看到并没有关于半同步的插件,那我们来装一下半同步插件:

root@localhost [(none)]> install plugin rpl_semi_sync_master soname 'semisync_master.so'; 
Query OK, 0 rows affected (0.00 sec)

root@localhost [(none)]>install plugin rpl_semi_sync_slave soname 'semisync_slave.so';
Query OK, 0 rows affected (0.01 sec)

实际上主库上不要装rpl_semi_sync_slave插件,我们这里考虑到以后自动化的问题,统一安装了。
安装后再次查看插件,可以看到版同步的插件已经安装完成。

root@localhost [(none)]>show plugins;
+----------------------------+----------+--------------------+--------------------+---------+
| Name                       | Status   | Type               | Library            | License |
+----------------------------+----------+--------------------+--------------------+---------+
| binlog                     | ACTIVE   | STORAGE ENGINE     | NULL               | GPL     |
| mysql_native_password      | ACTIVE   | AUTHENTICATION     | NULL               | GPL     |
| sha256_password            | ACTIVE   | AUTHENTICATION     | NULL               | GPL     |
| PERFORMANCE_SCHEMA         | ACTIVE   | STORAGE ENGINE     | NULL               | GPL     |
| MRG_MYISAM                 | ACTIVE   | STORAGE ENGINE     | NULL               | GPL     |
| MEMORY                     | ACTIVE   | STORAGE ENGINE     | NULL               | GPL     |
| InnoDB                     | ACTIVE   | STORAGE ENGINE     | NULL               | GPL     |
| INNODB_TRX                 | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_LOCKS               | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_LOCK_WAITS          | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_CMP                 | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_CMP_RESET           | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_CMPMEM              | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_CMPMEM_RESET        | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_CMP_PER_INDEX       | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_CMP_PER_INDEX_RESET | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_BUFFER_PAGE         | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_BUFFER_PAGE_LRU     | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_BUFFER_POOL_STATS   | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_TEMP_TABLE_INFO     | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_METRICS             | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_FT_DEFAULT_STOPWORD | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_FT_DELETED          | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_FT_BEING_DELETED    | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_FT_CONFIG           | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_FT_INDEX_CACHE      | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_FT_INDEX_TABLE      | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_SYS_TABLES          | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_SYS_TABLESTATS      | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_SYS_INDEXES         | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_SYS_COLUMNS         | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_SYS_FIELDS          | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_SYS_FOREIGN         | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_SYS_FOREIGN_COLS    | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_SYS_TABLESPACES     | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_SYS_DATAFILES       | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_SYS_VIRTUAL         | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| CSV                        | ACTIVE   | STORAGE ENGINE     | NULL               | GPL     |
| MyISAM                     | ACTIVE   | STORAGE ENGINE     | NULL               | GPL     |
| ARCHIVE                    | ACTIVE   | STORAGE ENGINE     | NULL               | GPL     |
| partition                  | ACTIVE   | STORAGE ENGINE     | NULL               | GPL     |
| BLACKHOLE                  | ACTIVE   | STORAGE ENGINE     | NULL               | GPL     |
| FEDERATED                  | DISABLED | STORAGE ENGINE     | NULL               | GPL     |
| ngram                      | ACTIVE   | FTPARSER           | NULL               | GPL     |
| rpl_semi_sync_master       | ACTIVE   | REPLICATION        | semisync_master.so | GPL     |
| rpl_semi_sync_slave        | ACTIVE   | REPLICATION        | semisync_slave.so  | GPL     |
+----------------------------+----------+--------------------+--------------------+---------+
  • Slave
    做同样动作
root@localhost [(none)]>install plugin rpl_semi_sync_master soname 'semisync_master.so';
ERROR 2006 (HY000): MySQL server has gone away
No connection. Trying to reconnect...
Connection id:    7
Current database: *** NONE ***

Query OK, 0 rows affected (0.02 sec)

root@localhost [(none)]>install plugin rpl_semi_sync_slave soname 'semisync_slave.so';
Query OK, 0 rows affected (0.01 sec)
root@localhost [(none)]>show plugins;
+----------------------------+----------+--------------------+--------------------+---------+
| Name                       | Status   | Type               | Library            | License |
+----------------------------+----------+--------------------+--------------------+---------+
| binlog                     | ACTIVE   | STORAGE ENGINE     | NULL               | GPL     |
| mysql_native_password      | ACTIVE   | AUTHENTICATION     | NULL               | GPL     |
| sha256_password            | ACTIVE   | AUTHENTICATION     | NULL               | GPL     |
| PERFORMANCE_SCHEMA         | ACTIVE   | STORAGE ENGINE     | NULL               | GPL     |
| MRG_MYISAM                 | ACTIVE   | STORAGE ENGINE     | NULL               | GPL     |
| MEMORY                     | ACTIVE   | STORAGE ENGINE     | NULL               | GPL     |
| InnoDB                     | ACTIVE   | STORAGE ENGINE     | NULL               | GPL     |
| INNODB_TRX                 | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_LOCKS               | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_LOCK_WAITS          | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_CMP                 | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_CMP_RESET           | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_CMPMEM              | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_CMPMEM_RESET        | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_CMP_PER_INDEX       | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_CMP_PER_INDEX_RESET | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_BUFFER_PAGE         | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_BUFFER_PAGE_LRU     | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_BUFFER_POOL_STATS   | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_TEMP_TABLE_INFO     | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_METRICS             | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_FT_DEFAULT_STOPWORD | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_FT_DELETED          | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_FT_BEING_DELETED    | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_FT_CONFIG           | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_FT_INDEX_CACHE      | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_FT_INDEX_TABLE      | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_SYS_TABLES          | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_SYS_TABLESTATS      | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_SYS_INDEXES         | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_SYS_COLUMNS         | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_SYS_FIELDS          | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_SYS_FOREIGN         | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_SYS_FOREIGN_COLS    | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_SYS_TABLESPACES     | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_SYS_DATAFILES       | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| INNODB_SYS_VIRTUAL         | ACTIVE   | INFORMATION SCHEMA | NULL               | GPL     |
| CSV                        | ACTIVE   | STORAGE ENGINE     | NULL               | GPL     |
| MyISAM                     | ACTIVE   | STORAGE ENGINE     | NULL               | GPL     |
| ARCHIVE                    | ACTIVE   | STORAGE ENGINE     | NULL               | GPL     |
| partition                  | ACTIVE   | STORAGE ENGINE     | NULL               | GPL     |
| BLACKHOLE                  | ACTIVE   | STORAGE ENGINE     | NULL               | GPL     |
| FEDERATED                  | DISABLED | STORAGE ENGINE     | NULL               | GPL     |
| ngram                      | ACTIVE   | FTPARSER           | NULL               | GPL     |
| rpl_semi_sync_master       | ACTIVE   | REPLICATION        | semisync_master.so | GPL     |
| rpl_semi_sync_slave        | ACTIVE   | REPLICATION        | semisync_slave.so  | GPL     |
+----------------------------+----------+--------------------+--------------------+---------+
46 rows in set (0.00 sec)

看到两个插件都已经处于ACTIVE状态了。

二、开启半同步

root@localhost [(none)]>set global rpl_semi_sync_master_enabled=1;
Query OK, 0 rows affected (0.00 sec)

root@localhost [(none)]>show global variables like '%rpl_semi%';
+-------------------------------------------+------------+
| Variable_name                             | Value      |
+-------------------------------------------+------------+
| rpl_semi_sync_master_enabled              | ON         |
| rpl_semi_sync_master_timeout              | 10000      |
| 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               | OFF        |
| rpl_semi_sync_slave_trace_level           | 32         |
+-------------------------------------------+------------+
8 rows in set (0.00 sec)

这里对参数做个简单的说明:
rpl_semi_sync_master_enabled:主库启用半同步
rpl_semi_sync_master_timeout:半同步超时时间,即从库在超过这个时间无应答后,改为异步同步,生产上可以调小一些,设置为1-2秒即可
rpl_semi_sync_master_wait_for_slave_count :多个从库的环境下,只等待一个从库应答
rpl_semi_sync_master_wait_point:半主从同步模式,5.7默认AFTER_SYNC,生产建议为AFTER_SYNC ,5.6为AFTER COMMIT
rpl_semi_sync_slave_enabled:从库启用半同步
更改配置文件

  • master
    rpl_semi_sync_master_enabled=1 #主库配置文件添加,表示以后启动MySQL将会自动开启半同步复制
  • slave
    rpl_semi_sync_slave_enabled=1

三、半同步测试

从库停止复制以后在主库建表测试

  • slave:
root@localhost [(none)]>stop slave;
Query OK, 0 rows affected (0.01 sec)
  • master
root@localhost [(none)]>use xucl;
Database changed
root@localhost [xucl]>create table t1(id int);
Query OK, 0 rows affected (10.01 sec)

可以看到,主库在10秒内没有收到应答后自动改为异步复制,然后再引擎层提交事务。

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