MySQL普通錶轉換成分割槽表的兩種方法舉例

以jxfp_data_bak表為例:
mysql> desc jxfp_data_bak;
+-------------+--------------+------+-----+---------+----------------+
| Field       | Type         | Null | Key | Default | Extra          |
+-------------+--------------+------+-----+---------+----------------+
| id          | bigint(20)   | NO   | PRI | NULL    | auto_increment |
| SH          | varchar(32)  | YES  |     | NULL    |                |
| KPJH        | varchar(32)  | YES  |     | NULL    |                |
| ZFJH        | varchar(10)  | YES  |     | NULL    |                |
| TYPE        | char(3)      | YES  |     | NULL    |                |
| MONTH       | char(10)     | YES  |     | NULL    |                |
| STATUS      | varchar(255) | YES  | MUL | NULL    |                |
| CREATE_TIME | datetime     | YES  |     | NULL    |                |
| UPDATE_TIME | datetime     | YES  |     | NULL    |                |
| FP_DATA     | mediumtext   | YES  |     | NULL    |                |
+-------------+--------------+------+-----+---------+----------------+
10 rows in set (0.00 sec)



方法1:用alter table table_name partition by命令重建分割槽表

mysql> alter table jxfp_data_bak PARTITION BY KEY(SH) PARTITIONS 8;
ERROR 1503 (HY000): A PRIMARY KEY must include all columns in the table's partitioning function


直接增加主鍵會報錯:
mysql> alter table jxfp_data_bak add PRIMARY KEY(SH);
ERROR 1068 (42000): Multiple primary key defined

需要刪除原先的主鍵，並增加聯合主鍵:
mysql> ALTER TABLE `jxfp_data_bak` DROP PRIMARY KEY, ADD PRIMARY KEY(`id`,`SH`);

檢視新的表結構:
mysql> desc jxfp_data_bak;
+-------------+--------------+------+-----+---------+----------------+
| Field       | Type         | Null | Key | Default | Extra          |
+-------------+--------------+------+-----+---------+----------------+
| id          | bigint(20)   | NO   | PRI | NULL    | auto_increment |
| SH          | varchar(32)  | NO   | PRI |         |                |   --SH列為聯合主鍵
| KPJH        | varchar(32)  | YES  |     | NULL    |                |
| ZFJH        | varchar(10)  | YES  |     | NULL    |                |
| TYPE        | char(3)      | YES  |     | NULL    |                |
| MONTH       | char(10)     | YES  |     | NULL    |                |
| STATUS      | varchar(255) | YES  |     | NULL    |                |
| CREATE_TIME | datetime     | YES  |     | NULL    |                |
| UPDATE_TIME | datetime     | YES  |     | NULL    |                |
| FP_DATA     | mediumtext   | YES  |     | NULL    |                |
+-------------+--------------+------+-----+---------+----------------+
10 rows in set (0.00 sec)


用alter table table_name partition by命令重建分割槽表:
建hash分割槽會報錯,因為hash分割槽欄位只能是整型，不能是varchar型:
mysql> alter table jxfp_data_bak PARTITION BY HASH(SH) PARTITIONS 8;
ERROR 1659 (HY000): Field 'SH' is of a not allowed type for this type of partitioning


但建key分割槽則可以成功:
mysql> alter table jxfp_data_bak PARTITION BY KEY(SH) PARTITIONS 8;
Query OK, 78317 rows affected (3.42 sec)
Records: 78317  Duplicates: 0  Warnings: 0


測試分割槽功能:
mysql> explain partitions select * from jxfp_data_bak;
+----+-------------+---------------+-------------------------+------+---------------+------+---------+------+-------+-------+
| id | select_type | table         | partitions              | type | possible_keys | key  | key_len | ref  | rows  | Extra |
+----+-------------+---------------+-------------------------+------+---------------+------+---------+------+-------+-------+
|  1 | SIMPLE      | jxfp_data_bak | p0,p1,p2,p3,p4,p5,p6,p7 | ALL  | NULL          | NULL | NULL    | NULL | 43588 | NULL  |
+----+-------------+---------------+-------------------------+------+---------------+------+---------+------+-------+-------+
1 row in set (0.00 sec)


以上我們可以看到全表掃描跨越了七個分割槽(p0--p7),說明分割槽表功能生效。


方法2:利用create table命令重建分割槽表

mysql> CREATE TABLE `jxfp_data` (
    ->   `id` bigint(20) NOT NULL AUTO_INCREMENT,
    ->   `SH` varchar(32) DEFAULT NULL COMMENT '稅號',
    ->   `KPJH` varchar(32) DEFAULT NULL COMMENT '開票機號',
    ->   `ZFJH` varchar(10) DEFAULT NULL COMMENT '主分機號',
    ->   `TYPE` char(3) DEFAULT NULL,
    ->   `MONTH` char(10) DEFAULT NULL,
    ->   `STATUS` varchar(255) DEFAULT NULL COMMENT '解析狀態標識',
    ->   `CREATE_TIME` datetime DEFAULT NULL COMMENT '插入時間',
    ->   `UPDATE_TIME` datetime DEFAULT NULL COMMENT '更新時間',
    ->   `FP_DATA` mediumtext COMMENT '發票資料',
    ->   PRIMARY KEY (`id`,`SH`)
    -> ) ENGINE=InnoDB AUTO_INCREMENT=81060 DEFAULT CHARSET=utf8 PARTITION BY LINEAR KEY (SH) PARTITIONS 8;
Query OK, 0 rows affected (0.08 sec)        --建立分割槽表成功

注意:如果原表裡有主鍵欄位，則MYSQL的分割槽欄位必須包含在主鍵欄位內，否則會建立失敗，因此上面需要定義兩個聯合主鍵(`id`,`SH`)

插回資料:
mysql> insert into jxfp_data select * from ixinnuo_sjcj.jxfp_data;
Query OK, 745540 rows affected, 1 warning (28.21 sec)
Records: 745540  Duplicates: 0  Warnings: 1

測試:
mysql> explain partitions select * from jxfp_data;
+----+-------------+-----------+-------------------------+------+---------------+------+---------+------+--------+-------+
| id | select_type | table     | partitions              | type | possible_keys | key  | key_len | ref  | rows   | Extra |
+----+-------------+-----------+-------------------------+------+---------------+------+---------+------+--------+-------+
|  1 | SIMPLE      | jxfp_data | p0,p1,p2,p3,p4,p5,p6,p7 | ALL  | NULL          | NULL | NULL    | NULL | 695986 | NULL  |
+----+-------------+-----------+-------------------------+------+---------------+------+---------+------+--------+-------+
1 row in set (0.00 sec)