爲什麼要有mysql優化，具體是什麼東西，我們通過一個案例來大概瞭解一下：
提個需求： 我們需要做一張5000個記錄的一張表。
1.我們先用引擎是innodb;來做。
我們先要寫一個存儲過程：存儲過程是怎麼寫的，請參考
存儲過程
drop procedure if exists pro;
delimiter $$
create procedure pro()
begin
declare add_name varchar(50);
declare add_age int(11);
declare i int(11) default 1;
while(i<100) do
set i:= i+1;
set add_name := concat("hourse",i);
set add_age := floor(rand()*100);
insert into dept(dept_name,age) values(add_name,add_age);
end while;
end$$
delimiter ;運行上面的代碼，我們設置存儲過程成果，利用call調用存儲過程pro，實現在innodb引擎下插入100條數據。
mysql> drop procedure if exists pro;
Query OK, 0 rows affected (0.11 sec)
mysql> delimiter $$
mysql> create procedure pro()
-> begin
-> declare add_name varchar(50);
-> declare add_age int(11);
-> declare i int(11) default 1;
-> while(i<100) do
-> set i:= i+1;
-> set add_name := concat("hourse",i);
-> set add_age := floor(rand()*100);
-> insert into dept(dept_name,age) values(add_name,add_age);
-> end while;
-> end$$
Query OK, 0 rows affected (0.00 sec)
mysql> delimiter ;
mysql>
mysql>
mysql> call pro;
Query OK, 1 row affected (6.36 sec)####這裏我們發現利用了6s
mysql> select * from dept;
+---------+-----------+------+
| dept_id | dept_name | age |
+---------+-----------+------+
| 1 | hourse2 | 53 |
| 2 | hourse2 | 27 |
| 3 | hourse3 | 56 |
| 4 | hourse4 | 98 |
| 5 | hourse5 | 25 |
| 6 | hourse6 | 31 |
| 7 | hourse7 | 80 |
| 8 | hourse8 | 9 |
| 9 | hourse9 | 6 |
| 10 | hourse10 | 2 |
| 11 | hourse11 | 94 |
| 12 | hourse12 | 62 |
| 13 | hourse13 | 30 |
| 14 | hourse14 | 65 |
| 15 | hourse15 | 34 |
| 16 | hourse16 | 76 |
| 17 | hourse17 | 80 |
| 18 | hourse18 | 72 |
| 19 | hourse19 | 19 |
| 20 | hourse20 | 80 |
| 21 | hourse21 | 45 |
| 22 | hourse22 | 86 |
| 23 | hourse23 | 95 |
| 24 | hourse24 | 18 |
| 25 | hourse25 | 4 |
| 26 | hourse26 | 69 |
| 27 | hourse27 | 33 |
| 28 | hourse28 | 59 |
| 29 | hourse29 | 96 |
| 30 | hourse30 | 1 |
| 31 | hourse31 | 21 |
| 32 | hourse32 | 2 |
| 33 | hourse33 | 46 |
| 34 | hourse34 | 23 |
| 35 | hourse35 | 81 |
| 36 | hourse36 | 35 |
| 37 | hourse37 | 31 |
| 38 | hourse38 | 51 |
| 39 | hourse39 | 61 |
| 40 | hourse40 | 54 |
| 41 | hourse41 | 87 |
| 42 | hourse42 | 75 |
| 43 | hourse43 | 13 |
| 44 | hourse44 | 39 |
| 45 | hourse45 | 57 |
| 46 | hourse46 | 70 |
| 47 | hourse47 | 80 |
| 48 | hourse48 | 91 |
| 49 | hourse49 | 16 |
| 50 | hourse50 | 6 |
| 51 | hourse51 | 81 |
| 52 | hourse52 | 90 |
| 53 | hourse53 | 6 |
| 54 | hourse54 | 63 |
| 55 | hourse55 | 94 |
| 56 | hourse56 | 85 |
| 57 | hourse57 | 42 |
| 58 | hourse58 | 56 |
| 59 | hourse59 | 53 |
| 60 | hourse60 | 97 |
| 61 | hourse61 | 26 |
| 62 | hourse62 | 41 |
| 63 | hourse63 | 29 |
| 64 | hourse64 | 20 |
| 65 | hourse65 | 16 |
| 66 | hourse66 | 19 |
| 67 | hourse67 | 47 |
| 68 | hourse68 | 79 |
| 69 | hourse69 | 54 |
| 70 | hourse70 | 34 |
| 71 | hourse71 | 7 |
| 72 | hourse72 | 36 |
| 73 | hourse73 | 60 |
| 74 | hourse74 | 90 |
| 75 | hourse75 | 71 |
| 76 | hourse76 | 88 |
| 77 | hourse77 | 26 |
| 78 | hourse78 | 64 |
| 79 | hourse79 | 46 |
| 80 | hourse80 | 39 |
| 81 | hourse81 | 55 |
| 82 | hourse82 | 61 |
| 83 | hourse83 | 40 |
| 84 | hourse84 | 19 |
| 85 | hourse85 | 74 |
| 86 | hourse86 | 13 |
| 87 | hourse87 | 46 |
| 88 | hourse88 | 88 |
| 89 | hourse89 | 6 |
| 90 | hourse90 | 64 |
| 91 | hourse91 | 4 |
| 92 | hourse92 | 27 |
| 93 | hourse93 | 26 |
| 94 | hourse94 | 49 |
| 95 | hourse95 | 69 |
| 96 | hourse96 | 97 |
| 97 | hourse97 | 77 |
| 98 | hourse98 | 94 |
| 99 | hourse99 | 39 |
| 100 | hourse100 | 16 |
+---------+-----------+------+
100 rows in set (0.00 sec)我們先會發現innodb用時6秒多插入了100條數據。
我們把數據刪除掉。
mysql> truncate dept;
Query OK, 0 rows affected (0.10 sec)
mysql> select * from dept;
Empty set (0.00 sec)
更換表的引擎
alter table dept engine myisam;mysql> alter table dept engine myisam;
Query OK, 0 rows affected (0.29 sec)
Records: 0 Duplicates: 0 Warnings: 0
mysql> show create table dept;
+-------+-----------------------------------------------------------------------
--------------------------------------------------------------------------------
----------------------------------------------------------------------+
| Table | Create Table
|
+-------+-----------------------------------------------------------------------
--------------------------------------------------------------------------------
----------------------------------------------------------------------+
| dept | CREATE TABLE `dept` (
`dept_id` int(11) NOT NULL AUTO_INCREMENT,
`dept_name` varchar(100) DEFAULT NULL COMMENT '部門名字',
`age` int(11) DEFAULT NULL,
PRIMARY KEY (`dept_id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 |
+-------+-----------------------------------------------------------------------
--------------------------------------------------------------------------------
----------------------------------------------------------------------+
1 row in set (0.00 sec)我們在把pro的存儲過程設置一下：
mysql> call pro;
Query OK, 1 row affected (0.01 sec)
mysql> select * from dept;
+---------+-----------+------+
| dept_id | dept_name | age |
+---------+-----------+------+
| 1 | hourse2 | 64 |
| 2 | hourse3 | 70 |
| 3 | hourse4 | 61 |
| 4 | hourse5 | 93 |在myisam下我們發現使用時間爲0.01s，比innodb的6s要小了很多。這就是大致的一個mysql的優化實例，詳細的優化文章，請聽下回分解。
