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 #)

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.-linux-glibc2.-x86_64/bin/mysqld --defaults-file=/etc/my-.cnf --initialize --user=mysql3307

错误日志

--17T09::53.905909+:  [System] [MY-] [Server] /usr/local/mysql-8.0.-linux-glibc2.-x86_64/bin/mysqld (mysqld 8.0.) initializing of server in progress as process      

--17T09::56.474963+:  [Warning] [MY-] [Server] Ignoring --plugin-load[_add] list as the server is running with --initialize(-insecure).
--17T09::57.620921+:  [ERROR] [MY-] [Server] unknown variable 'rpl_semi_sync_master_enabled=1'.
--17T09::57.621099+:  [ERROR] [MY-] [Server] The designated data directory /database/mysql/data// is unusable. You can remove all files that the server added to it.
--17T09::57.621375+:  [ERROR] [MY-] [Server] Aborting
--17T09::58.676973+:  [System] [MY-] [Server] /usr/local/mysql-8.0.-linux-glibc2.-x86_64/bin/mysqld: Shutdown complete (mysqld 8.0.)  MySQL Community Server - GPL.
--17T09::59.113521+:  [System] [MY-] [Server] /usr/local/mysql-8.0.-linux-glibc2.-x86_64/bin/mysqld (mysqld 8.0.) starting as process
mysqld: Table 'mysql.plugin' doesn't exist
--17T09::59.941092+:  [ERROR] [MY-] [Server] Could not open the mysql.plugin table. Please perform the MySQL upgrade procedure.
--17T09::00.013579+:  [Warning] [MY-] [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.-linux-glibc2.-x86_64.tar.xz --port= --max-mem= install

验证一下

mysql> select @@version;
+-----------+
| @@version |
+-----------+
| 8.0.    |
+-----------+
 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     |
+---------------------------------+----------+--------------------+--------------------+---------+
 rows in set (0.00 sec)

dbm-agent 

dbm-agent 是一个开源的自动化工具，可以在 github 上看到到 https://github.com/Neeky/dbm-agent

文章转载自：https://www.sqlpy.com/blogs/books/1/chapters/13/articles/109

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