InnoDB--------獨立表空間平滑遷移
阿新 • • 發佈：2017-07-21
mysql dba data transfer
1. 背景
* InnoDB的表空間可以是共享的或獨立的。如果是共享表空間，則所有的表空間都放在一個文件裏：ibdata1,ibdata2..ibdataN，這種情況下，目前應該還沒辦法實現表空間的遷移，除非完全遷移。
* 不管是共享還是獨立表空間，InnoDB每個數據表的元數據(metadata)總是保存在 ibdata1 這個共享表空間裏，因此該文件必不可少，它還可以用來保存各種數據字典等信息。
* 獨立表空間中數據文件單獨存放在.ibd文件中。
* MySQL 5.6版本開始支持獨立表空間導入與導出。
2. 環境 [ 2臺DB實例, MySQL 5.6表遷移至MySQL5.7 ]
* 源實例 MySQL
mysql> show variables like ‘innodb%version‘; +----------------+--------+ | Variable_name | Value | +----------------+--------+ | innodb_version | 5.6.36 | +----------------+--------+ 1 row in set (0.01 sec) mysql> show variables like ‘datadir‘; +---------------+--------------------+ | Variable_name | Value | +---------------+--------------------+ | datadir | /data/mysql_data6/ | +---------------+--------------------+ 1 row in set (0.00 sec)
* 目的實例 MySQL
mysql> show variables like ‘innodb%version‘; +----------------+--------+ | Variable_name | Value | +----------------+--------+ | innodb_version | 5.7.18 | +----------------+--------+ 1 row in set (0.00 sec) mysql> show variables like ‘datadir‘; +---------------+--------------------+ | Variable_name | Value | +---------------+--------------------+ | datadir | /data/mysql_data7/ | +---------------+--------------------+ 1 row in set (0.01 sec)
* 源實例 MySQL 遷移的數據庫與表信息
mysql> select database(); +------------+ | database() | +------------+ | mytest | +------------+ 1 row in set (0.00 sec) mysql> show create table users; +-------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | Table | Create Table | +-------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | users | CREATE TABLE `users` ( `id` bigint(20) NOT NULL AUTO_INCREMENT, `name` varchar(255) NOT NULL, `sex` enum(‘M‘,‘F‘) NOT NULL DEFAULT ‘M‘, `age` int(11) NOT NULL DEFAULT ‘0‘, PRIMARY KEY (`id`) ) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8mb4 | +-------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ 1 row in set (0.01 sec) mysql> select * from users; +----+-------+-----+-----+ | id | name | sex | age | +----+-------+-----+-----+ | 1 | tom | M | 25 | | 2 | jak | F | 38 | | 3 | sea | M | 43 | | 4 | lisea | M | 36 | +----+-------+-----+-----+ 4 rows in set (0.00 sec)
3. 平滑遷移實戰 [ 遷移mytest數據庫下users表 ]
* 目的MySQL實例創建相同的數據庫與表 [ MySQL 5.7中創建表需要指定row_format=compact ]
mysql> create database mytest character set utf8mb4;
Query OK, 1 row affected (0.03 sec)
mysql> use mytest;
Database changed
mysql> CREATE TABLE `users` (
-> `id` bigint(20) NOT NULL AUTO_INCREMENT,
-> `name` varchar(255) NOT NULL,
-> `sex` enum(‘M‘,‘F‘) NOT NULL DEFAULT ‘M‘,
-> `age` int(11) NOT NULL DEFAULT ‘0‘,
-> PRIMARY KEY (`id`)
-> ) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8mb4 row_format=compact;
Query OK, 0 rows affected (0.59 sec)
mysql> system ls -l /data/mysql_data7/mytest/
total 64
-rw-r----- 1 mysql mysql 67 Jul 18 05:21 db.opt
-rw-r----- 1 mysql mysql 8648 Jul 18 05:21 users.frm
-rw-r----- 1 mysql mysql 49152 Jul 18 05:21 users.ibd* 目的MySQL實例丟棄表空間
mysql> alter table users discard tablespace; Query OK, 0 rows affected (0.01 sec) mysql> system ls -l /data/mysql_data7/mytest/ total 16 -rw-r----- 1 mysql mysql 67 Jul 18 05:21 db.opt -rw-r----- 1 mysql mysql 8648 Jul 18 05:21 users.frm
* 源MySQL實例刷新表至磁盤並加lock,並且當前表quiesce狀態，只讀，且創建.cfg metadata文件
mysql> flush tables users for export; Query OK, 0 rows affected (0.00 sec)
* 從源MySQL實例服務止拷貝表文件users.ibd, users.cfg文件至目的MySQL實例中
[[email protected] ~]# cp -v /data/mysql_data6/mytest/users.{cfg,ibd} /data/mysql_data7/mytest/
`/data/mysql_data6/mytest/users.cfg‘ -> `/data/mysql_data7/mytest/users.cfg‘
`/data/mysql_data6/mytest/users.ibd‘ -> `/data/mysql_data7/mytest/users.ibd‘* 修改目的MySQL實例數據文件下拷貝文件的所有者與所有組
[[email protected] ~]# chown -v mysql.mysql /data/mysql_data7/mytest/users.{cfg,ibd}
changed ownership of `/data/mysql_data7/mytest/users.cfg‘ to mysql:mysql
changed ownership of `/data/mysql_data7/mytest/users.ibd‘ to mysql:mysql* 源MySQL實例釋放lock
mysql> unlock tables; Query OK, 0 rows affected (0.00 sec)
* 目的MySQL實例加載表空間
mysql> alter table users import tablespace; Query OK, 0 rows affected (0.04 sec)
* 查看目的MySQL實例表數據 [ MySQL5.6數據成功遷移過來 ]
mysql> select * from users; +----+-------+-----+-----+ | id | name | sex | age | +----+-------+-----+-----+ | 1 | tom | M | 25 | | 2 | jak | F | 38 | | 3 | sea | M | 43 | | 4 | lisea | M | 36 | +----+-------+-----+-----+ 4 rows in set (0.00 sec)
4. 註意問題
* MySQL 5.6數據遷移到MySQL5.7時，如果創建目的表時不指定row_format，import表數據時會報錯，原因在於MySQL 5.6中是Antelope，在MySQL 5.7中是Barracuda，主要是在表壓縮和行的動態格式上有所改變。
5. 總結
以需求驅動技術，技術本身沒有優略之分，只有業務之分。
本文出自 “sea” 博客，請務必保留此出處http://lisea.blog.51cto.com/5491873/1949559
InnoDB--------獨立表空間平滑遷移