当mysqld服务进程访问损坏的表时,数据库会直接崩溃退出。如果在遭遇到损坏的表时,不希望出现这种结果,请将参数innodb_corrupt_table_action变量值设置为salvage
,该值会跳过损坏的表,不会使mysqld服务进程崩溃,导致整个数据库无法启动。
注:
1)MySQL没有此参数,请切换至Percona或者MariaDB
2)该参数只能适配独立表空间 innodb_file_per_table = 1
故障复现:
1)创建一个t1表,然后到/data/目录下,用重定向命令清空数据
echo > t1.ibd
2)直接shutdown关闭mysqld进程
3)启动mysqld进程后,如果没有在my.cnf文件里增加该参数,启动时会报错,报错日志如下:
2023-02-10T16:30:18.491764+08:00 0 [Warning] [MY-012637] [InnoDB] 1024 bytes should have been read. Only 0 bytes read. Retrying for the remaining bytes.
2023-02-10T16:30:18.491777+08:00 0 [Warning] [MY-012638] [InnoDB] Retry attempts for reading partial data failed.
2023-02-10T16:30:18.491789+08:00 0 [ERROR] [MY-012642] [InnoDB] Tried to read 1024 bytes at offset 0, but was only able to read 0
2023-02-10T16:30:18.491801+08:00 0 [ERROR] [MY-012646] [InnoDB] File ./test/t1.ibd: 'read' returned OS error 0. Cannot continue operation
2023-02-10T16:30:18.491812+08:00 0 [ERROR] [MY-012981] [InnoDB] Cannot continue operation.
4)将参数innodb_corrupt_table_action变量值设置为salvage
,启动mysqld进程,再次查看该表
mysql> select * from t1;
ERROR 1812 (HY000): Tablespace is missing for table `test`.`t1`.
5)你可以在其他节点上DUMP数据还原,从而恢复t1表。
总结
在甲骨文MySQL里,解决方案是将参数innodb_force_recovery值设置为1-6,确保数据库可以正常启动,但值大于0后,可以对表进行 select, create, drop 操作,而 insert, update 或者 delete 这类操作是不允许的,影响的是全局。
在Perocna/MariaDB里,可以用innodb_corrupt_table_action参数代替innodb_force_recovery,这样没有损坏的表,可以正常读写操作,影响的是局部。
标签:02,10T16,read,t1,Percona,innodb,action,table From: https://blog.51cto.com/hcymysql/6049650