如何在删除ibdata1的情况下恢复
参考：https://www.cnblogs.com/ivictor/p/5784258.html
基本步骤
1， 将原数据文件保存至其他路径
2，创建同名表结构
3， 导出表空间
4， 将原数据.ibd文件copy回来
5， 导入表空间
创建表t1，并插入数据
mysql> show create table t1;
+-------+--------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table |
+-------+--------------------------------------------------------------------------------------------------------------------------+
| t1 | CREATE TABLE `t1` (
`id` int(11) DEFAULT NULL,
`name` varchar(100) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8 |
+-------+--------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)
mysql> select * from t1;
+------+--------+
| id | name |
+------+--------+
| 1 | qing |
| 1 | 大秦 |
+------+--------+
2 rows in set (0.00 sec)
mysql>将ibdata1和ib_logfile0-2移走：
[root@localhost data]# ls
auto.cnf ibdata1 ib_logfile1 itdb localhost-relay-bin.000005 master.info mysql-bin.000001 mysql-bin.000003 mysql-bin.000005 percona relay-log.info tony
books ib_logfile0 ib_logfile2 localhost.localdomain.pid localhost-relay-bin.index mysql mysql-bin.000002 mysql-bin.000004 mysql-bin.index performance_schema test
[root@localhost data]#
[root@localhost data]# mkdir /tmp/bak
[root@localhost data]# mv ibdata1 /tmp/bak
[root@localhost data]# mv ib_log* /tmp/bak
[root@localhost data]# ls
auto.cnf itdb localhost-relay-bin.000005 master.info mysql-bin.000001 mysql-bin.000003 mysql-bin.000005 percona relay-log.info tony
books localhost.localdomain.pid localhost-relay-bin.index mysql mysql-bin.000002 mysql-bin.000004 mysql-bin.index performance_schema test
[root@localhost data]#重启mysql，系统会重新创建者几个文件
[root@localhost data]# service mysqld restart
Shutting down MySQL.... SUCCESS!
Starting MySQL.. SUCCESS!
[root@localhost data]# ls
auto.cnf ibdata1 ib_logfile1 itdb localhost-relay-bin.000006 master.info mysql-bin.000001 mysql-bin.000003 mysql-bin.000005 mysql-bin.index performance_schema test
books ib_logfile0 ib_logfile2 localhost.localdomain.pid localhost-relay-bin.index mysql mysql-bin.000002 mysql-bin.000004 mysql-bin.000006 percona relay-log.info tony
[root@localhost data]#查看error log也可以看到创建的记录：
2018-01-21 13:15:32 2753 [Note] InnoDB: The first specified data file ./ibdata1 did not exist: a new database to be created!
2018-01-21 13:15:32 2753 [Note] InnoDB: Setting file ./ibdata1 size to 12 MB
2018-01-21 13:15:32 2753 [Note] InnoDB: Database physically writes the file full: wait...
2018-01-21 13:15:32 2753 [Note] InnoDB: Setting log file ./ib_logfile101 size to 32 MB
2018-01-21 13:15:32 2753 [Note] InnoDB: Setting log file ./ib_logfile1 size to 32 MB
2018-01-21 13:15:32 2753 [Note] InnoDB: Setting log file ./ib_logfile2 size to 32 MB
2018-01-21 13:15:32 2753 [Note] InnoDB: Renaming log file ./ib_logfile101 to ./ib_logfile0然后登陆mysql，访问刚刚创建的t1，显示 ERROR 1146 (42S02): Table 'tony.t1' doesn't exist
mysql> show tables;
+----------------+
| Tables_in_tony |
+----------------+
| t1 |
+----------------+
1 row in set (0.00 sec)
mysql> desc t1;
ERROR 1146 (42S02): Table 'tony.t1' doesn't exist
mysql> select * from t1;
ERROR 1146 (42S02): Table 'tony.t1' doesn't exist
mysql>为什么呢？虽然我们开启了innodb_file_per_table功能，让innodb的数据存储在t1.ibd下，但是共享表空间ibdata1中存储有数据字典，innodb没有数据字典，那么它就找不到这个表了；参考
https://blog.csdn.net/jswangchang/article/details/81138240
[root@localhost data]# cat /etc/my.cnf | grep innodb_file_per_table
innodb_file_per_table=1 #very table has individule data space
[root@localhost data]# ls tony/
db.opt t1.frm t1.ibd接下来我们把表数据移动至其他地方，然后创建相同表结构的表：
[root@localhost tony]# mv * /tmp/bak/
[root@localhost tony]# ls
[root@localhost tony]# ls /tmp/bak/
db.opt ibdata1 ib_logfile0 ib_logfile1 ib_logfile2 t1.frm t1.ibdmysql> show tables;
Empty set (0.00 sec)
mysql> CREATE TABLE `t1` (
-> `id` int(11) DEFAULT NULL,
-> `name` varchar(100) DEFAULT NULL
-> ) ENGINE=InnoDB DEFAULT CHARSET=utf8;
ERROR 1146 (42S02): Table 'tony.t1' doesn't exist
mysql>
mysql> drop table t1;
ERROR 1051 (42S02): Unknown table 'tony.t1'
mysql> CREATE TABLE `t1` (
-> `id` int(11) DEFAULT NULL,
-> `name` varchar(100) DEFAULT NULL
-> ) ENGINE=InnoDB DEFAULT CHARSET=utf8;
Query OK, 0 rows affected (0.03 sec)
mysql> show tables;
+----------------+
| Tables_in_tony |
+----------------+
| t1 |
+----------------+
1 row in set (0.00 sec)
此时t1是个新表，里面没有数据，此时我们导出表空间，导出后ibd文件就看不到了，然后我们把原t1.ibd文件copy过来；然后修改属组和属主权限
mysql> select * from t1;
Empty set (0.01 sec)
mysql> alter table t1 discard tablespace;
Query OK, 0 rows affected (0.01 sec)
mysql>
[2]+ Stopped mysql (wd: /tmp/mysql-5.6/data)
(wd now: /tmp/mysql-5.6/data/tony)
[root@localhost tony]# ls
t1.frm
[root@localhost tony]# cp /tmp/bak/t1.ibd ./
[root@localhost tony]# ls
t1.frm t1.ibd
[root@localhost tony]# ll
total 108
-rw-rw---- 1 mysql mysql 8586 Jan 21 13:24 t1.frm
-rw-r----- 1 root root 98304 Jan 21 13:27 t1.ibd
[root@localhost tony]# chown mysql.mysql t1.ibdmysql> alter table t1 import tablespace;
Query OK, 0 rows affected, 1 warning (0.03 sec)
mysql> show warnings;
+---------+------+-----------------------------------------------------------------------------------------------------------------------------------------+
| Level | Code | Message |
+---------+------+-----------------------------------------------------------------------------------------------------------------------------------------+
| Warning | 1810 | InnoDB: IO Read error: (2, No such file or directory) Error opening './tony/t1.cfg', will attempt to import without schema verification |
+---------+------+-----------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)
mysql> select * from t1;
+------+--------+
| id | name |
+------+--------+
| 1 | qing |
| 1 | 大秦 |
+------+--------+
2 rows in set (0.00 sec)
mysql> flush tables;
Query OK, 0 rows affected (0.01 sec)
mysql> select * from t1;
+------+--------+
| id | name |
+------+--------+
| 1 | qing |
| 1 | 大秦 |
+------+--------+
2 rows in set (0.01 sec)然后导入表空间，再select就可以查到数据了；flush tables刷新内存后依然可以；
删除ibdata1的时候，会影响所有的innodb表，包括系统表中的innodb表；有哪些系统表是Innodb? 在V5.6中比较少，只有下面几个，但是在V5.7以后就有很多了；
mysqlv5.6 >select table_schema,table_name,engine from information_schema.tables where engine='innodb' and table_schema='mysql';
+--------------+----------------------+--------+
| table_schema | table_name | engine |
+--------------+----------------------+--------+
| mysql | innodb_index_stats | InnoDB |
| mysql | innodb_table_stats | InnoDB |
| mysql | slave_master_info | InnoDB |
| mysql | slave_relay_log_info | InnoDB |
| mysql | slave_worker_info | InnoDB |
+--------------+----------------------+--------+
5 rows in set (0.01 sec)
mysqlv5.6 >select * from mysql.innodb_table_stats;
ERROR 1146 (42S02): Table 'mysql.innodb_table_stats' doesn't existmysql5.7 >select table_schema,table_name,engine from information_schema.tables where engine='innodb' and table_schema in ('mysql','sys','information_schema','performance_schema');
+--------------------+---------------------------+--------+
| table_schema | table_name | engine |
+--------------------+---------------------------+--------+
| information_schema | COLUMNS | InnoDB |
| information_schema | EVENTS | InnoDB |
| information_schema | OPTIMIZER_TRACE | InnoDB |
| information_schema | PARAMETERS | InnoDB |
| information_schema | PARTITIONS | InnoDB |
| information_schema | PLUGINS | InnoDB |
| information_schema | PROCESSLIST | InnoDB |
| information_schema | ROUTINES | InnoDB |
| information_schema | TRIGGERS | InnoDB |
| information_schema | VIEWS | InnoDB |
| mysql | engine_cost | InnoDB |
| mysql | gtid_executed | InnoDB |
| mysql | help_category | InnoDB |
| mysql | help_keyword | InnoDB |
| mysql | help_relation | InnoDB |
| mysql | help_topic | InnoDB |
| mysql | innodb_index_stats | InnoDB |
| mysql | innodb_table_stats | InnoDB |
| mysql | plugin | InnoDB |
| mysql | server_cost | InnoDB |
| mysql | servers | InnoDB |
| mysql | slave_master_info | InnoDB |
| mysql | slave_relay_log_info | InnoDB |
| mysql | slave_worker_info | InnoDB |
| mysql | time_zone | InnoDB |
| mysql | time_zone_leap_second | InnoDB |
| mysql | time_zone_name | InnoDB |
| mysql | time_zone_transition | InnoDB |
| mysql | time_zone_transition_type | InnoDB |
| sys | sys_config | InnoDB |
+--------------------+---------------------------+--------+
30 rows in set (0.01 sec)
如果ibdata1被删除了要恢复，必须新建表结构，按照上面的步骤来一遍；