SQL简单实用的优化方法
分析表：MyISAM、InnoDB、BDB
mysql> analyze table payment; #MyISAM 使用myisamchk -a
+----------------+---------+----------+----------+
| Table | Op | Msg_type | Msg_text |
+----------------+---------+----------+----------+
| sakila.payment | analyze | status | OK |
+----------------+---------+----------+----------+
1 row in set (0.10 sec)
mysql>
mysql> check table payment_myisam ; #MyISAM、InnoDB #也可以检查视图
+-----------------------+-------+----------+----------+
| Table | Op | Msg_type | Msg_text |
+-----------------------+-------+----------+----------+
| sakila.payment_myisam | check | status | OK |
+-----------------------+-------+----------+----------+
1 row in set (0.00 sec)
mysql>
优化表：MyISAM、InnoDB、BDB
mysql> optimize table payment_myisam ;
+-----------------------+----------+----------+----------+
| Table | Op | Msg_type | Msg_text |
+-----------------------+----------+----------+----------+
| sakila.payment_myisam | optimize | status | OK |
+-----------------------+----------+----------+----------+
1 row in set (0.01 sec)
mysql>
使用独立表空间：
mysql> show variables like "innodb_file_per_table";
+-----------------------+-------+
| Variable_name | Value |
+-----------------------+-------+
| innodb_file_per_table | ON |
+-----------------------+-------+
1 row in set (0.00 sec)
mysql> set GLOBAL innodb_file_per_table = on;
Query OK, 0 rows affected (0.00 sec)
mysql>
删除大量数据后InnoDB表可以通过alter table：
mysql> alter table payment engine=innodb;
Query OK, 0 rows affected (4.63 sec)
Records: 0 Duplicates: 0 Warnings: 0
mysql>
关于字符集的设置：
character_set_server=utf8mb4
default_character-set=utf8mb4