Mysql自动按月表分区

很久没有碰DB了。最近需要做一个日志表，因此重新拾了下。实现了下自动按月表分区
开发环境为Mysql 5.7.28

参考资料：
Mysql分区表及自动创建分区Partition（按日）

核心的两个存储过程：
auto_create_partition为创建表分区，调用后为该表创建到下月结束的表分区。
auto_del_partition为删除表分区，方便历史数据空间回收。

DELIMITER $$
DROP PROCEDURE IF EXISTS auto_create_partition$$
CREATE PROCEDURE `auto_create_partition`(IN `table_name` varchar(64))
BEGIN
SET @next_month:=CONCAT(date_format(date_add(now(),interval 2 month),’%Y%m’),’01’);
SET @SQL = CONCAT( ‘ALTER TABLE `’, table_name, ‘`’,
‘ ADD PARTITION (PARTITION p’, @next_month, ” VALUES LESS THAN (TO_DAYS(“,
@next_month ,”)) );” );
PREPARE STMT FROM @SQL;
EXECUTE STMT;
DEALLOCATE PREPARE STMT;
END$$

DROP PROCEDURE IF EXISTS auto_del_partition$$
CREATE PROCEDURE `auto_del_partition`(IN `table_name` varchar(64),IN `reserved_month` int)
BEGIN
DECLARE v_finished INTEGER DEFAULT 0;
DECLARE v_part_name varchar(100) DEFAULT “”;
DECLARE part_cursor CURSOR FOR
select partition_name from information_schema.partitions where table_schema = schema()
and table_name=@table_name and partition_description < TO_DAYS(CONCAT(date_format(date_sub(now(),interval reserved_month month),’%Y%m’),’01’));
DECLARE continue handler FOR
NOT FOUND SET v_finished = TRUE;
OPEN part_cursor;
read_loop: LOOP
FETCH part_cursor INTO v_part_name;
if v_finished = 1 then
leave read_loop;
end if;
SET @SQL = CONCAT( ‘ALTER TABLE `’, table_name, ‘` DROP PARTITION ‘, v_part_name, “;” );
PREPARE STMT FROM @SQL;
EXECUTE STMT;
DEALLOCATE PREPARE STMT;
END LOOP;
CLOSE part_cursor;
END$$

DELIMITER ; 
下面是示例

— 假设有个表叫records,设置分区条件为按end_time按月分区
DROP TABLE IF EXISTS `records`;
CREATE TABLE `records` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`start_time` datetime NOT NULL,
`end_time` datetime NOT NULL,
`memo` varchar(128) CHARACTER SET utf8mb4 NOT NULL,
PRIMARY KEY (`id`,`end_time`)
)
PARTITION BY RANGE (TO_DAYS(end_time))(
PARTITION p20200801 VALUES LESS THAN ( TO_DAYS(‘20200801’))
);

DROP EVENT IF EXISTS `records_auto_partition`;

— 创建一个Event,每月执行一次，同时最多保存6个月的数据
DELIMITER $$
CREATE EVENT `records_auto_partition`
ON SCHEDULE EVERY 1 MONTH ON COMPLETION PRESERVE
ENABLE
DO
BEGIN
call auto_create_partition(‘records’);
call auto_del_partition(‘records’,6);
END$$
DELIMITER ; 
几点注意事项：

对于Mysql 5.1以上版本来说，表分区的索引字段必须是主键
存储过程中，DECLARE 必须紧跟着BEGIN，否则会报看不懂的错误
游标的DECLARE需要在定义声明之后，否则会报错
如果是自己安装的Mysql，有可能Event功能是未开启的，在创建Event时会提示错误；修改my.cnf,在 [mysqld] 下添加event_scheduler=1后重启即可。

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版权声明：本文为CSDN博主「无边风月-风之羽翼」的原创文章，遵循CC 4.0 BY-SA版权协议，转载请附上原文出处链接及本声明。
原文链接：https://blog.csdn.net/gogoytgo/article/details/108267105