mysql5.7自动创建分区

实现了下自动按月表分区，开发环境为Mysql 5.7.28

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。