MySQL-8.0.18 引入了破坏性变更

MySQL-8.0.18 引入了破坏性变更

变更日志里面有这样一项

When the server is run with --initialize, there is no reason to load non-early plugins. The server now logs a warning and ignores 
any --plugin-load or --plugin-load-add options given with --initialize. (Bug #29622406)

也就是说当我们在做初始化的时，像半同步插件这样的非必要插件是不会被加载的，一旦我们在配置文件中加入了相应的配置项，整个初始化就会失败。

场景再现

配置文件(关键部分)

[mysqld]
## replication                                                                                   
rpl_semi_sync_master_enabled             = 1                                               
rpl_semi_sync_slave_enabled              = 1                                               
rpl_semi_sync_master_timeout             = 1000                                            
rpl_semi_sync_master_wait_point          = AFTER_SYNC                                      
rpl_semi_sync_master_wait_no_slave       = ON                                              
rpl_semi_sync_master_wait_for_slave_count = 1                                              
master_info_repository                   = table                                                 
sync_master_info                         = 10000                                                 
skip_slave_start                         = OFF                                                   
slave_load_tmpdir                        = /tmp/                                                 
plugin_load_add                          = semisync_master.so                                    
plugin_load_add                          = semisync_slave.so

初始化命令

/usr/local/mysql-8.0.18-linux-glibc2.12-x86_64/bin/mysqld --defaults-file=/etc/my-3307.cnf --initialize --user=mysql3307

错误日志

2019-10-17T09:40:53.905909+08:00 0 [System] [MY-013169] [Server] /usr/local/mysql-8.0.18-linux-glibc2.12-x86_64/bin/mysqld (mysqld 8.0.18) initializing of server in progress as process 8077     
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2019-10-17T09:40:56.474963+08:00 0 [Warning] [MY-013501] [Server] Ignoring --plugin-load[_add] list as the server is running with --initialize(-insecure).                                        
2019-10-17T09:40:57.620921+08:00 0 [ERROR] [MY-000067] [Server] unknown variable 'rpl_semi_sync_master_enabled=1'.                                                                                
2019-10-17T09:40:57.621099+08:00 0 [ERROR] [MY-013236] [Server] The designated data directory /database/mysql/data/3307/ is unusable. You can remove all files that the server added to it.       
2019-10-17T09:40:57.621375+08:00 0 [ERROR] [MY-010119] [Server] Aborting                         
2019-10-17T09:40:58.676973+08:00 0 [System] [MY-010910] [Server] /usr/local/mysql-8.0.18-linux-glibc2.12-x86_64/bin/mysqld: Shutdown complete (mysqld 8.0.18)  MySQL Community Server - GPL.      
2019-10-17T09:40:59.113521+08:00 0 [System] [MY-010116] [Server] /usr/local/mysql-8.0.18-linux-glibc2.12-x86_64/bin/mysqld (mysqld 8.0.18) starting as process 8165                               
mysqld: Table 'mysql.plugin' doesn't exist                                                       
2019-10-17T09:40:59.941092+08:00 0 [ERROR] [MY-010735] [Server] Could not open the mysql.plugin table. Please perform the MySQL upgrade procedure.                                                
2019-10-17T09:41:00.013579+08:00 0 [Warning] [MY-010015] [Repl] Gtid table is not ready to be used. Table 'mysql.gtid_executed' cannot be opened.

解决方案

方案一：由变更日志中提到的内容可以知道，我们只要在初始化时把非必要插件的内容从配置文件中去掉，初始化完成之后再加回来就行了。然而就要求 dba 特别能吃苦，特别能受累。

方案二：使用 dbm-agent 这个自动化工具，它已经对 MySQL-8.0.18 做了兼容，而且整个安装、配置、调优过程一行命令解决

# 一行命令完成安装、配置、调优
dbma-cli-single-instance --pkg=mysql-8.0.18-linux-glibc2.12-x86_64.tar.xz --port=3306 --max-mem=256 install

验证一下

mysql> select @@version;
+-----------+
| @@version |
+-----------+
| 8.0.18    |
+-----------+
1 row in set (0.00 sec)

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     |
| clone                           | ACTIVE   | CLONE              | mysql_clone.so     | GPL     |
+---------------------------------+----------+--------------------+--------------------+---------+
47 rows in set (0.00 sec)