Linux环境下修改MySQL数据库存储引擎

今天在执行Oracle数据库迁移至MySQL数据库时报出了一个错误信息：

Specified key was too long; max key length is 1000 bytes

百度发现，原来需要更改MySQL数据库的存储引擎为InnoDB，查询目前现有的存储引擎信息：

[root@test-121 ~]# mysql -u root -p
Enter password:
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 10
Server version: 5.1.71 Source distribution

Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> show engines;
+------------+---------+------------------------------------------------------------+--------------+------+------------+
| Engine     | Support | Comment                                                    | Transactions | XA   | Savepoints |
+------------+---------+------------------------------------------------------------+--------------+------+------------+
| MRG_MYISAM | YES     | Collection of identical MyISAM tables                      | NO           | NO   | NO         |
| CSV        | YES     | CSV storage engine                                         | NO           | NO   | NO         |
| MyISAM     | DEFAULT | Default engine as of MySQL 3.23 with great performance     | NO           | NO   | NO         |
| InnoDB     | YES     | Supports transactions, row-level locking, and foreign keys | YES          | YES  | YES        |
| MEMORY     | YES     | Hash based, stored in memory, useful for temporary tables  | NO           | NO   | NO         |
+------------+---------+------------------------------------------------------------+--------------+------+------------+
5 rows in set (0.00 sec)

mysql>

查询发现，默认的存储引擎为MyISAM，目前安装的MySQL数据库提供了对InnoDB引擎的支持。

更改方法如下：

修改“/etc/my.cnf”配置文件

[root@test-121 mysql]# cat /etc/my.cnf
[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
user=mysql
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0

default-storage-engine=InnoDB

[mysqld_safe]
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid

在[mysqld]节点下面增加“default-storage-engine=InnoDB”选项。

重启MySQL服务：

service mysqld restart

再次查看数据存储引擎信息：

mysql> show engines;
ERROR 2006 (HY000): MySQL server has gone away
No connection. Trying to reconnect...
Connection id:    10
Current database: *** NONE ***

+------------+---------+------------------------------------------------------------+--------------+------+------------+
| Engine     | Support | Comment                                                    | Transactions | XA   | Savepoints |
+------------+---------+------------------------------------------------------------+--------------+------+------------+
| MRG_MYISAM | YES     | Collection of identical MyISAM tables                      | NO           | NO   | NO         |
| CSV        | YES     | CSV storage engine                                         | NO           | NO   | NO         |
| MyISAM     | YES     | Default engine as of MySQL 3.23 with great performance     | NO           | NO   | NO         |
| InnoDB     | DEFAULT | Supports transactions, row-level locking, and foreign keys | YES          | YES  | YES        |
| MEMORY     | YES     | Hash based, stored in memory, useful for temporary tables  | NO           | NO   | NO         |
+------------+---------+------------------------------------------------------------+--------------+------+------------+
5 rows in set (0.01 sec)

发现已经将数据库存储引擎切换至InnoDB。

再次迁移数据库没有发生错误信息。

关键信息总结：

1、登录MySQL Console控制台

mysql –u root –p

2、查看数据库存储引擎

show engines;

3、MySQL数据库配置文件路径

/etc/my.cnf

4、增加数据存储引擎配置项

default-storage-engine=InnoDB

5、重启MySQL

service mysqld restart