INNODB 不支持
mysql> OPTIMIZE TABLE t; +--------+----------+----------+-------------------------------------------------------------------+ | Table | Op | Msg_type | Msg_text | +--------+----------+----------+-------------------------------------------------------------------+ | test.t | optimize | note | Table does not support optimize, doing recreate + analyze instead | //INNODB | test.t | optimize | status | OK | +--------+----------+----------+-------------------------------------------------------------------+ 2 rows in set (0.24 sec)
mysql> show create table t; +-------+-------------------------------------------------------------------------------------------------------------------------------------+ | Table | Create Table | +-------+-------------------------------------------------------------------------------------------------------------------------------------+ | t | CREATE TABLE `t` (`a` int(11) NOT NULL AUTO_INCREMENT,PRIMARY KEY (`a`) ) ENGINE=InnoDB AUTO_INCREMENT=8 DEFAULT CHARSET=utf8 | +-------+-------------------------------------------------------------------------------------------------------------------------------------+ 1 row in set (0.18 sec)
使 OPTIMIZE table 对 innodb 支持
mysqld --datadir=/data --basedir=/usr/local/mysql56 --user=mysql --gdb --skip-new
mysql> OPTIMIZE TABLE t; Query OK, 0 rows affected (0.27 sec) Records: 0 Duplicates: 0 Warnings: 0
原理：映射为 alter table
By default, OPTIMIZE TABLE does not work for tables created using any other storage engine and returns a result indicating this lack of support.
You can make OPTIMIZTABLE work for other storage engines by starting mysqld with the --skip-new option.
In this case, OPTIMIZE TABLE is just mapped to ALTER TABLE.
OPTIMIZE TABLE continues to use ALGORITHM=COPY under the following conditions:When the old_alter_table system variable is turned ON.
set old_alter_table=on; //alter table 修改表采用 algorithm=copy 方式When the mysqld --skip-new option is enabled.
google:
Everytime you do optimize MySQL, by using mysqlcheck -A -o or using ./mysql_optimize from here.
You may see the outputTable does not support optimize, doing recreate + analyze instead.It is because the table that you are using is InnoDB.You can optimize the InnoDB tables by using this.ALTER TABLE table.name ENGINE='InnoDB';This will create a copy of the original table, and drop the original table, and replace to the original place.Although this is safe, but I suggest you do backup and test first before doing this.
mysql> ALTER TABLE t ENGINE='InnoDB'; Query OK, 0 rows affected (0.29 sec) Records: 0 Duplicates: 0 Warnings: 0mysql> select * from t; +---+ | a | +---+ | 7 | +---+ 1 row in set (0.01 sec)
innodb的数据库不支持optimize，可以用ALTER TABLE table.name ENGINE='InnoDB'; 该方法会对旧表以复制的方式新建一个新表，然后删除旧表。虽然这个过程是安全的, 但是在进行操作时还是先进行备份为好
MyISAM:正常
mysql> show create table t; +-------+-------------------------------------------------------------------------------------------------------------------------------------+ | Table | Create Table | +-------+-------------------------------------------------------------------------------------------------------------------------------------+ | t | CREATE TABLE `t` (`a` int(11) NOT NULL AUTO_INCREMENT,PRIMARY KEY (`a`) ) ENGINE=MyISAM AUTO_INCREMENT=8 DEFAULT CHARSET=utf8 | +-------+-------------------------------------------------------------------------------------------------------------------------------------+ 1 row in set (0.00 sec)mysql> OPTIMIZE TABLE t; +--------+----------+----------+----------+ | Table | Op | Msg_type | Msg_text | +--------+----------+----------+----------+ | test.t | optimize | status | OK | +--------+----------+----------+----------+ 1 row in set (0.00 sec)
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