MySQL 更换MyISAM存储引擎为Innodb的操作记录

一般情况下，mysql会默认提供多种存储引擎,可以通过下面的查看:

1）查看mysql是否安装了innodb插件。
通过下面的命令结果可知，已经安装了innodb插件。

mysql> show plugins;
+------------+--------+----------------+---------+---------+
| Name       | Status | Type           | Library | License |
+------------+--------+----------------+---------+---------+
| binlog     | ACTIVE | STORAGE ENGINE | NULL    | GPL     |
| partition  | ACTIVE | STORAGE ENGINE | NULL    | GPL     |
| CSV        | ACTIVE | STORAGE ENGINE | NULL    | GPL     |
| MEMORY     | ACTIVE | STORAGE ENGINE | NULL    | GPL     |
| InnoDB     | ACTIVE | STORAGE ENGINE | NULL    | GPL     |
| MyISAM     | ACTIVE | STORAGE ENGINE | NULL    | GPL     |
| MRG_MYISAM | ACTIVE | STORAGE ENGINE | NULL    | GPL     |
+------------+--------+----------------+---------+---------+
7 rows in set (0.00 sec)

----------------------------------------------------------------------
如果发现没有安装innodb插件,可以执行下面语句进行安装：
mysql> install plugin innodb soname 'ha_innodb.so';
----------------------------------------------------------------------

2）查看mysql现在已提供什么存储引擎:

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)

3）查看mysql当前默认的存储引擎:

mysql> show variables like '%storage_engine%';
+----------------+--------+
| Variable_name  | Value  |
+----------------+--------+
| storage_engine | MyISAM |
+----------------+--------+
1 row in set (0.00 sec)

4）看某个表用了什么引擎(在显示结果里参数engine后面的就表示该表当前用的存储引擎):
mysql> show create table 表名;

mysql> show create table wx_share_log;
+--------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table        | Create Table                                                                                                                                                                                                                                                                                                       |
+--------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| wx_share_log | CREATE TABLE `wx_share_log` (
  `id` int(11) NOT NULL AUTO_INCREMENT COMMENT '微信分享日志自增ID',
  `reference_id` int(11) NOT NULL COMMENT '推荐的经纪人id',
  `create_time` datetime NOT NULL COMMENT '创建时间',
  PRIMARY KEY (`id`)
) ENGINE=MyISAM AUTO_INCREMENT=13 DEFAULT CHARSET=utf8                   |
+--------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

5）如何将MyISAM库导成INNODB引擎格式的:
在备份出的xxx.sql文件中把ENGINE=MyISAM全换成ENGINE=INNODB
再次导入就可以了。

6）转换表的命令:
mysql> alter table 表名 engine=innodb;

有上面可以查到看，本机mysql使用的存储引擎是默认的MyISAN，由于业务需要，先要将其存储引擎改为Innodb。
操作记录如下：

1）以安全模式关闭mysql
[root@dev mysql5.1.57]# mysqladmin -uroot -p shutdown
Enter password:
[root@dev mysql5.1.57]# ps -ef|grep mysql

2）备份my.cnf
[root@dev mysql5.1.57]# cp my.cnf my.cnf.old

3）修改my.cnf配置文件
[root@dev mysql5.1.57]# vim my.cnf
.....
[mysqld]                                        //在这个配置区域添加下面一行，指定存储引擎为innodb
default-storage-engine = InnoDB

4）删除/mysql/data目录下的ib_logfile0，ib_logfile1。删除或剪切到别处都行。
[root@dev var]# mv ib_logfile0 ib_logfile1 /tmp/back/

5）启动mysql，登陆mysql验证存储引擎是否已切换
[root@dev var]# /Data/app/mysql5.1.57/bin/mysqld_safe --defaults-file=/Data/app/mysql5.1.57/my.cnf &

mysql> show variables like '%storage_engine%';
+----------------+--------+
| Variable_name  | Value  |
+----------------+--------+
| storage_engine | InnoDB |
+----------------+--------+
1 row in set (0.00 sec)