Mysql 数据库

> 记录一次服务器断电异常重启后，数据库服务无法启动，数据库损坏，通过binlog文件恢复数据的步骤

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- ## 数据库服务无法启动
### 启动服务报错信息
```bash
systemd[1]: Starting LSB: start and stop MariaDB...
mysqld[8059]: 230704 09:40:27 mysqld_safe Starting mariadbd daemon with databases from /www/server/data
mysqld[8059]: /etc/rc.d/init.d/mysqld: line 263: kill: (8190) - No such process
mysqld[8059]: ERROR!
systemd[1]: mysqld.service: control process exited, code=exited status=1
systemd[1]: Failed to start LSB: start and stop MariaDB.
systemd[1]: Unit mysqld.service entered failed state.
systemd[1]: mysqld.service failed.
```
### 日志报错信息
````bash
230704 10:56:30 mysqld_safe Starting mariadbd daemon with databases from /www/server/data
2023-07-04 10:56:30 0 [Warning] option 'max_allowed_packet': unsigned value 107374182400 adjusted to 1073741824
2023-07-04 10:56:30 0 [Note] /www/server/mysql/bin/mariadbd (server 10.7.3-MariaDB-log) starting as process 10336 ...
2023-07-04 10:56:30 0 [Note] InnoDB: Compressed tables use zlib 1.2.7
2023-07-04 10:56:30 0 [Note] InnoDB: Number of transaction pools: 1
2023-07-04 10:56:30 0 [Note] InnoDB: Using crc32 + pclmulqdq instructions
2023-07-04 10:56:30 0 [Note] InnoDB: Using Linux native AIO
2023-07-04 10:56:30 0 [Note] InnoDB: Initializing buffer pool, total size = 268435456, chunk size = 134217728
2023-07-04 10:56:30 0 [Note] InnoDB: Completed initialization of buffer pool
2023-07-04 10:56:30 0 [Note] InnoDB: Starting crash recovery from checkpoint LSN=42397,42397
2023-07-04 10:56:30 0 [ERROR] InnoDB: Missing FILE_CHECKPOINT at 42397 between the checkpoint 42397 and the end 45976651.
2023-07-04 10:56:30 0 [ERROR] InnoDB: Plugin initialization aborted with error Generic error
2023-07-04 10:56:30 0 [Note] InnoDB: Starting shutdown...
2023-07-04 10:56:31 0 [ERROR] Plugin 'InnoDB' init function returned error.
2023-07-04 10:56:31 0 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
2023-07-04 10:56:31 0 [Note] Plugin 'FEEDBACK' is disabled.
2023-07-04 10:56:31 0 [ERROR] Unknown/unsupported storage engine: InnoDB
2023-07-04 10:56:31 0 [ERROR] Aborting
````
### 解决方法
自行查找 `ib_logfile0` 文件所在目录，并删除
```bash
ib_logfile0文件是InnoDB存储引擎使用的一个重要文件，它用于记录数据库的事务日志。如果该文件出现问题，可能会导致MariaDB启动失败或出现错误。
```
- ## 数据库数据损坏
> 通过binlog文件
### 转化为sql文件
```bash
mysqlbinlog 文件名称 -d 数据库名称> filename_binlog.sql
```
### 登录数据库执行
```bash
source filename_binlog.sql
```
以上，实施过程中可能有不同的报错提示，具体情况具体解决即可。

参考文章：https://juejin.cn/post/7090789934453227527