Plugin ‘FEEDBACK’ is disabled

MySQL低版本升级高版本一般会出现Plugin 'FEEDBACK' is disabled这个错误,通常还伴随The InnoDB memory heap is disabled问题一起出现。

如果是The memory heap is disabled错误可以在[mysqld]下方增加"_use_sys_malloc = 1",即使用系统自动分配内存。而Plugin 'FEEDBACK' is disabled只需要在[mysqld]下方增加“feedback=ON”即可开启。

参考MariaDB提供的文档:Feedback Plugin

InnoDB: If you are attempting downgrade from MySQL 5.7.9 or later

: If you are attempting downgrade from 5.7.9 or later

这是一个版本问题,之前安装过mysql 5.7,再回到mariadb 5.5出现的问题。之后我搜了下网上很多人有这个问题。错误全文:

160916 17:03:21 mysqld_safe Starting mysqld daemon with databases from /var/lib/
2016-09-16 17:03:22 139911928530976 [Note] /usr/sbin/mysqld (mysqld 10.1.17-) starting as process 16541 ...
2016-09-16 17:03:22 139911928530976 [Note] : Using mutexes to ref count buffer pool pages
2016-09-16 17:03:22 139911928530976 [Note] InnoDB: The InnoDB memory heap is disabled
2016-09-16 17:03:22 139911928530976 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
2016-09-16 17:03:22 139911928530976 [Note] InnoDB: GCC builtin __atomic_thread_fence() is used for memory barrier
2016-09-16 17:03:22 139911928530976 [Note] InnoDB: Compressed tables use zlib 1.2.3
2016-09-16 17:03:22 139911928530976 [Note] InnoDB: Using Linux native AIO
2016-09-16 17:03:22 139911928530976 [Note] InnoDB: Using SSE crc32 instructions
2016-09-16 17:03:22 139911928530976 [Note] InnoDB: Initializing buffer pool, size = 128.0M
2016-09-16 17:03:22 139911928530976 [Note] InnoDB: Completed initialization of buffer pool
2016-09-16 17:03:22 139911928530976 [Note] InnoDB: Highest supported file format is Barracuda.
InnoDB: No valid checkpoint found.
InnoDB: If you are attempting downgrade from MySQL 5.7.9 or later,
InnoDB: please refer to http://dev.mysql.com/doc/refman/5.6/en/upgrading-downgrading.html
InnoDB: If this error appears when you are creating an InnoDB database,
InnoDB: the problem may be that during an earlier attempt you managed
InnoDB: to create the InnoDB data files, but log file creation failed.
InnoDB: If that is the case, please refer to
InnoDB: http://dev.mysql.com/doc/refman/5.6/en/error-creating-innodb.html
2016-09-16 17:03:22 139911928530976 [ERROR] Plugin 'InnoDB' init function returned error.
2016-09-16 17:03:22 139911928530976 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
2016-09-16 17:03:22 139911928530976 [Note] Plugin 'FEEDBACK' is disabled.
2016-09-16 17:03:22 139911928530976 [ERROR] Unknown/unsupported storage engine: InnoDB
2016-09-16 17:03:22 139911928530976 [ERROR] Aborting

160916 17:03:22 mysqld_safe mysqld from pid file /var/lib/mysql/iZ236priv51Z.pid ended

继续阅读InnoDB: If you are attempting downgrade from MySQL 5.7.9 or later

Unknown/unsupported storage engine: InnoDB

5.5以及以上版本出现Unknown/unsupported storage engine: 错误,是由于你的存储引擎使用了,但是数据库默认没有开启innodb

方法一:可以先将数据库改为MyISAM,再将mysql关闭innodb

在my.cnf [mysqld]下增加:

方法二:直接mysql启用innodb引擎

在my.cnf [mysqld]下增加:

注意事项

以上操作都必须关闭mysql再修改my.cnf。