mysql中數據庫learn文件夾結構:

看一下表sales的定義：

show create  table sales \G

*************************** 1. row ***************************
Table: sales
Create Table: CREATE TABLE `sales` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `amount` double NOT NULL,
  `order_day` datetime NOT NULL,
  PRIMARY
 
 KEY (`id`,`order_day`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1
/*!50100 PARTITION BY RANGE (YEAR(order_day))
(PARTITION p_2010 VALUES LESS THAN (2010) ENGINE = InnoDB,
 PARTITION p_2011 VALUES LESS THAN (2011) ENGINE = InnoDB,
 PARTITION p_2012 VALUES LESS THAN (2012) ENGINE = InnoDB,
 PARTITION p_catchall VALUES
 
 LESS THAN MAXVALUE ENGINE = InnoDB) */
1 row in set (0.00 sec)

表p_key的定義

show create  table p_key \G

*************************** 1. row ***************************
Table: p_key
Create Table: CREATE TABLE `p_key` (
  `id` int(10) NOT NULL AUTO_INCREMENT,
  `keyname` char(20) DEFAULT NULL,
  `keyval`
 
 varchar(1000) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=MyISAM AUTO_INCREMENT=12 DEFAULT CHARSET=utf8
/*!50100 PARTITION BY KEY (id)
PARTITIONS 4 */
1 row in set (0.01 sec)

對於MyISAM引擎，一張表對於存儲了3個文件。fm存儲表結構。myi存放索引，myd存放數據。

但p_key相應的另一個文件p_key.par。

又一次創建一個Range分區的表fuhui_log，體驗分區查詢：

DROP TABLE IF EXISTS fuhui_log;
CREATE TABLE fuhui_log (
    object_id int(11),
    title varchar(20) NOT NULL  ,
    content varchar(20) ,
    time int(11),
    primary key (object_id)
)
PARTITION BY range (object_id)
(
    PARTITION p1 VALUES less than (5000),
    PARTITION p2 VALUES less than (10000),
    PARTITION p3 VALUES less than MAXVALUE
);

自己定義存儲過程，向數據庫中插入20000條數據：

delimiter //
create procedure fun_fuhui_log() 
begin
    declare i int;
    set i = 1;
    while i < 20000 do
        insert into fuhui_log(object_id,title,content,time) values (i,concat(‘title_‘,i),‘test content‘,i);
        set i = i+1;
    end while;
end
//

調用存儲過程，進行數據插入：

delimiter ;
call fun_fuhui_log();

獲取插入數據結果：

 select count(*) from fuhui_log;

查詢結果為19999，耗時：1 row in set (0.01 sec)；

select * from fuhui_log where object_id = 13588;

耗時0.00 sec

依據如上的步驟。創建一個基本表，並改動存儲過程，插入相同的數據：

DROP TABLE IF EXISTS fuhui_log2;
CREATE TABLE fuhui_log2 (
    object_id int(11),
    title varchar(20) NOT NULL  ,
    content varchar(20) ,
    time int(11),
    primary key (object_id)
);

數據結構設計的太簡單，數據量太小。看不出效果來，重先改動存儲過程。插入80000條數據：

while i < 80000 do
        replace into fuhui_log2(object_id,title,content,time) values (i,concat(‘title_‘,i),‘test content‘,i);
        set i = i+1;
end while;

select count(*) from fuhui_log2;

運行結果：1 row in set (0.02 sec)

select count(*) from fuhui_log;

運行結果：1 row in set (0.03 sec)【沒有依照邏輯出牌】

這個樣例非常失敗，改動表結構。去掉primary key

 alter table fuhui_log drop primary key;
 alter table fuhui_log2 drop primary key;

樣例仍然比較失敗，運行的效率非常難發現

select * from fuhui_log where object_id = 56770 \G

耗時：0.05sec

select * from fuhui_log2 where object_id = 56770 \G

耗時0.06sec

對於count統計，fuhui_log比fuhui_log2耗時都多。count的並行計算，都被我給玷汙了

改動分區結構，又一次計算：

 alter table fuhui_log reorganize partition p3 into (
 partition p3_1 values less than (30000),
 partition p3_2 values less than (50000),
 partition p3_3 values less than MAXVALUE);

查看又一次分區後的結果：

select table_schema,table_name,partition_name,PARTITION_METHOD from infor
mation_schema.partitions where table_name=‘fuhui_log‘;

然後又一次計算：

select count(*) from fuhui_log ;

運行效果0.04sec，跟fuhui_log2的統計時間相等了。可是

select * from fuhui_log where object_id = 56770 \G

運行時間變成了0.02sec

竟然已經寫這麽久了，今天就此罷筆吧

MySQL-分區表-1