《MySQL系列-部署维护》通过表的.frm和.idb文件备份MySQL表

MySQL备份表(.frm,.idb文件)

目的: 利用表的.frm和.idb文件备份MySQL表

一、找到目标表的.frm和.idb文件

‍♀1.在服务器上找到对应的文件，如果不清楚MySQL的数据路径在哪，可以参考如下:

[root@zxy_master /]# find / -iname 'bootstrap.frm'
/var/lib/mysql/bigdata/bootstrap.frm

‍♀2.找到/var/lib/mysql/bigdata目录，bigdata为MySQL的一个数据库名称，bootstrap是bigdata数据库下的一张表。一个表一般有两个文件，比如bootstrap表有bootstrap.frm,bootstrap.idb文件

[root@zxy_master /]# cd /var/lib/mysql/bigdata/
[root@zxy_master bigdata]# ls
bootstrap.frm  bootstrap.ibd

二、在备份机上创建相同结构的数据库和表

‍♀1.为保险起见，直接查看原库原表的建表语句

mysql> show create database bigdata;
+----------+------------------------------------------------------------------+
| Database | Create Database                                                  |
+----------+------------------------------------------------------------------+
| maxwell  | CREATE DATABASE `bigdata` /*!40100 DEFAULT CHARACTER SET utf8 */ |
+----------+------------------------------------------------------------------+
1 row in set (0.00 sec)

mysql> show create table bigdata.bootstrap;
+-----------+----------------------------------------------------------------------------
| Table     | Create Table                                                               
| bootstrap | CREATE TABLE `bootstrap` (
  `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `database_name` varchar(255) NOT NULL,
  `table_name` varchar(255) NOT NULL,
  `where_clause` varchar(255) DEFAULT NULL,
  `is_complete` tinyint(1) unsigned NOT NULL DEFAULT '0',
  `inserted_rows` bigint(20) unsigned NOT NULL DEFAULT '0',
  `total_rows` bigint(20) unsigned NOT NULL DEFAULT '0',
  `created_at` datetime DEFAULT NULL,
  `started_at` datetime DEFAULT NULL,
  `completed_at` datetime DEFAULT NULL,
  `binlog_file` varchar(255) DEFAULT NULL,
  `binlog_position` int(10) unsigned DEFAULT '0',
  `client_id` varchar(255) CHARACTER SET latin1 NOT NULL DEFAULT 'maxwell',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=4 DEFAULT CHARSET=utf8 |
+-----------+----------------------------------------------------------------------------
1 row in set (0.00 sec)

mysql>

‍♀2.在备份机上执行建库建表语句

mysql> CREATE DATABASE `bigdata`;
Query OK, 1 row affected (0.00 sec)

mysql> use bigdata;
Database changed

mysql> CREATE TABLE `bootstrap` (
    ->   `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
    ->   `database_name` varchar(255) NOT NULL,
    ->   `table_name` varchar(255) NOT NULL,
    ->   `where_clause` varchar(255) DEFAULT NULL,
    ->   `is_complete` tinyint(1) unsigned NOT NULL DEFAULT '0',
    ->   `inserted_rows` bigint(20) unsigned NOT NULL DEFAULT '0',
    ->   `total_rows` bigint(20) unsigned NOT NULL DEFAULT '0',
    ->   `created_at` datetime DEFAULT NULL,
    ->   `started_at` datetime DEFAULT NULL,
    ->   `completed_at` datetime DEFAULT NULL,
    ->   `binlog_file` varchar(255) DEFAULT NULL,
    ->   `binlog_position` int(10) unsigned DEFAULT '0',
    ->   `client_id` varchar(255) CHARACTER SET latin1 NOT NULL DEFAULT 'maxwell',
    ->   PRIMARY KEY (`id`)
    -> ) ENGINE=InnoDB AUTO_INCREMENT=4 DEFAULT CHARSET=utf8;
Query OK, 0 rows affected (0.05 sec)

mysql>

‍♀3.查看备份机的/var/lib/mysql/bigdata目录下，是否生成对应.frm,.idb文件

[root@zxy_slave1 bigdata]# ls
bootstrap.frm  bootstrap.ibd  db.opt

三、清除表空间

‍♀1.执行命令，将bootstrap表的表空间清除，清除后bootstrap.idb文件会消失

mysql> alter table bootstrap discard tablespace;
Query OK, 0 rows affected (0.05 sec)

‍♀2.再次查看备份机的/var/lib/mysql/bigdata目录下，.idb文件是否消失

[root@zxy_slave1 bigdata]# ls
bootstrap.frm  db.opt

四、关闭数据库，复制.frm,.idb文件

‍♀1.关闭数据库

[root@zxy_slave1 mysql]# systemctl stop mysqld
[root@zxy_slave1 mysql]#

‍♀2.从主机复制bootstrap.frm,bootstrap.idb文件到备份机的指定目录

[root@zxy_master bigdata]# scp bootstrap.frm bootstrap.ibd [email protected]:/var/lib/mysql/bigdata
The authenticity of host 'slave1.spunsugar.top ' can't be established.
ECDSA key fingerprint is SHA256:C/+BHxQ00jdfgmaqAKHrdxx2HBl27GdHjCcerelvB9tH3s.
ECDSA key fingerprint is MD5:5e:08:d4:56:ad:24:cd:96:f9:ea:cr:68:51:7c:89:32.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added 'slave1.spunsugar.top' (ECDSA) to the list of known hosts.
[email protected]'s password:
bootstrap.frm                                                                                                           100% 9092     3.4MB/s   00:00
bootstrap.ibd                                                                                                           100%   96KB  13.3MB/s   00:00
[root@zxy_master bigdata]#

‍♀3.再次查看备份机的/var/lib/mysql/bigdata目录下，两个文件是否复制成功

[root@zxy_slave1 bigdata]# ll
total 112
-rw-r----- 1 mysql mysql  9092 Aug 30 15:21 bootstrap.frm
-rw-r----- 1 root  root  98304 Aug 30 15:21 bootstrap.ibd
-rw-r----- 1 mysql mysql    65 Aug 30 15:07 db.opt

五、启动数据库，导入表空间

‍♀1.启动数据库

[root@zxy_slave1 mysql]# systemctl start mysqld

‍♀2.检查库表是否存在

mysql> use bigdata;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed, 1 warning
mysql> show tables;
+-------------------+
| Tables_in_bigdata |
+-------------------+
| bootstrap         |
+-------------------+
1 row in set (0.00 sec)

‍♀3.导入表空间

mysql> alter table bootstrap import tablespace;
ERROR 1812 (HY000): Tablespace is missing for table `bigdata`.`bootstrap`.

## 在这里执行导入表空间命令后，会发现找不到表空间。
## 想想上一步清除表空间的时候，对应表的.idb文件是不是消失了
## 那么这里的找不到表空间，是否也跟.idb文件有关呢
## 我们再查看一下bigdata目录下有什么异常:

[root@zxy_slave1 bigdata]# ll
-rw-r----- 1 mysql mysql  9092 Aug 30 15:21 bootstrap.frm
-rw-r----- 1 root  root  98304 Aug 30 15:21 bootstrap.ibd
-rw-r----- 1 mysql mysql    65 Aug 30 15:07 db.opt

## 这里可以看到bootstrap.idb对应的用户和用户组是root
## 根据要求这些文件的用户和用户组必须是mysql
## 因为bootstrap.frm是覆盖后的文件，仍保留前文件的这些属性
## 而bootstrap.idb是新文件，而我当前使用的是root用户，所以用户和用户组是root
## 这里手动调整一下:

[root@zxy_slave1 bigdata]# chown mysql:mysql bootstrap.ibd
[root@zxy_slave1 bigdata]# ll
total 112
-rw-r----- 1 mysql mysql  9092 Aug 30 15:21 bootstrap.frm
-rw-r----- 1 mysql mysql 98304 Aug 30 15:21 bootstrap.ibd
-rw-r----- 1 mysql mysql    65 Aug 30 15:07 db.opt

## 再次导入表空间
mysql> alter table bootstrap import tablespace;
Query OK, 0 rows affected, 1 warning (0.07 sec)

## 查看表数据，已经成功备份

mysql> select *
    -> from bootstrap;
+----+---------------+---------------+--------------+-------------+---------------+------------+------------+---------------------+---------------------+-------------+-----------------+-----------+
| id | database_name | table_name    | where_clause | is_complete | inserted_rows | total_rows | created_at | started_at          | completed_at        | binlog_file | binlog_position | client_id |
+----+---------------+---------------+--------------+-------------+---------------+------------+------------+---------------------+---------------------+-------------+-----------------+-----------+
|  1 | bigdata       | base_province | NULL         |           1 |            34 |          0 | NULL       | 2022-06-18 12:43:36 | 2022-06-18 12:43:36 | NULL        |               0 | maxwell   |
|  2 | bigdata       | base_province | NULL         |           1 |            34 |          0 | NULL       | 2022-06-18 12:46:26 | 2022-06-18 12:46:26 | NULL        |               0 | maxwell   |
|  3 | bigdata       | base_province | NULL         |           1 |            34 |          0 | NULL       | 2022-06-18 12:47:31 | 2022-06-18 12:47:31 | NULL        |               0 | maxwell   |
+----+---------------+---------------+--------------+-------------+---------------+------------+------------+---------------------+---------------------+-------------+-----------------+-----------+
3 rows in set (0.00 sec)