mysql在原有表的基礎上添加分區

我們現在有一張表，tb_member_login_logs 用戶登錄日志表，但數據量太大，需要分區，建議新增一個days字段，int類型，值為 Ymd。

ALTER TABLE `tb_member_login_logs` ADD COLUMN `days` INT (11) UNSIGNED NOT NULL DEFAULT 19700101 COMMENT '日期(格式:Ymd)' AFTER `ID`;

mysql創建分區，分區的字段必須在主鍵內，不然后報如下錯誤：

1503 - A PRIMARY KEY must include all columns in the table's partitioning function

所以我們需要創建一個聯合主鍵，首先把 主鍵 ID 自增刪除，

ALTER TABLE `tb_member_login_logs` MODIFY COLUMN `id` INT (11) UNSIGNED NOT NULL COMMENT 'ID' FIRST;

然后再刪除主鍵 ID

ALTER TABLE `tb_member_login_logs` DROP PRIMARY KEY;

添加 ID 與 days 的聯合主鍵

ALTER TABLE `tb_member_login_logs` ADD PRIMARY KEY (`id`, `days`);

然后恢復 ID 的自增

ALTER TABLE `tb_member_login_logs` MODIFY COLUMN `id` INT (11) UNSIGNED NOT NULL AUTO_INCREMENT COMMENT 'ID' FIRST;

然后根據需要創建分區

ALTER TABLE `tb_member_login_logs` PARTITION BY RANGE(days) (
	PARTITION `p197001` VALUES LESS THAN (19700101),
	PARTITION `p202003` VALUES LESS THAN (20200301),
	PARTITION `p202004` VALUES LESS THAN (20200401),
	PARTITION `p202005` VALUES LESS THAN (20200501),
	PARTITION `p202006` VALUES LESS THAN (20200601),
	PARTITION `p202007` VALUES LESS THAN (20200701),
	PARTITION `p202008` VALUES LESS THAN (20200801),
	PARTITION `p202009` VALUES LESS THAN (20200901),
	PARTITION `p202010` VALUES LESS THAN (20201001),
	PARTITION `p202011` VALUES LESS THAN (20201101),
	PARTITION `p202012` VALUES LESS THAN (20201201),
	PARTITION `p202101` VALUES LESS THAN (20210101),
	PARTITION `p202102` VALUES LESS THAN (20210201),
	PARTITION `p202103` VALUES LESS THAN (20210301)
);

當然這種做法，運行時間會比較長。

可以創建一個結構與老表一樣並分好區的新表，把老表的數據導入新表中。