概述

Mysql不能自动创建分区,需要使用mysql event事件的方式自动创建分区，今天主要分享一下在MYSQL数据库应如何实现自动创建分区。

1、准备测试表及数据

CREATE TABLE `t1` (  `id` bigint(20) NOT NULL COMMENT 'id',  `insert_user` varchar(128) CHARACTER SET utf8 COLLATE utf8_bin DEFAULT NULL COMMENT 'Insert User',  `insert_date` datetime NOT NULL COMMENT 'Insert Date',  PRIMARY KEY (`id`,insert_date) USING BTREE,  KEY `fsl_idx_order_release_insert_date` (`insert_date`) USING BTREE) ENGINE=InnoDB DEFAULT CHARSET=utf8 ROW_FORMAT=DYNAMIC COMMENT='test'/*!50500 PARTITION BY RANGE  COLUMNS(insert_date)( PARTITION p202007 VALUES LESS THAN ('2020-08-01') ENGINE = InnoDB, PARTITION p202008 VALUES LESS THAN ('2020-09-01') ENGINE = InnoDB) */insert into t1 values (1,'hwb',now()),(1,'hwb2',now()+1),(1,'hwb3',now()+2);

2、相关存储过程

每次执行先校验当前分区是否存在，如果存在则不处理；不存在则创建

DELIMITER //#该表所在数据库名称USE `ycdb` // DROP PROCEDUREIF	EXISTS `create_partition_by_month` // CREATE PROCEDURE `create_partition_by_month` ( IN_SCHEMANAME VARCHAR ( 64 ), IN_TABLENAME VARCHAR ( 64 ) ) BEGIN	DECLARE		ROWS_CNT INT UNSIGNED;	DECLARE		BEGINTIME TIMESTAMP;	DECLARE		ENDTIME INT UNSIGNED;	DECLARE		PARTITIONNAME VARCHAR ( 16 );	DECLARE		ENDTIME_DATETIME VARCHAR ( 30 );		SET BEGINTIME = DATE( NOW( ) - INTERVAL DAY ( NOW( ) ) DAY + INTERVAL 1 DAY + INTERVAL 1 MONTH );    select BEGINTIME;	SET PARTITIONNAME = DATE_FORMAT( BEGINTIME, 'p%Y%m' );    select PARTITIONNAME;	SET ENDTIME = UNIX_TIMESTAMP( BEGINTIME + INTERVAL 1 MONTH );	select endtime;	SET ENDTIME_DATETIME = FROM_UNIXTIME( ENDTIME );    select ENDTIME_DATETIME;	SELECT		COUNT( * ) INTO ROWS_CNT 	FROM		information_schema.PARTITIONS 	WHERE		table_schema = IN_SCHEMANAME 		AND table_name = IN_TABLENAME 		AND partition_name = PARTITIONNAME;	IF		ROWS_CNT = 0 THEN				SET @SQL = CONCAT( 'ALTER TABLE `', IN_SCHEMANAME, '`.`', IN_TABLENAME, '`', ' ADD PARTITION (PARTITION ', PARTITIONNAME, " VALUES LESS THAN ('", ENDTIME_DATETIME, "') ENGINE = InnoDB);" );		PREPARE STMT 		FROM			@SQL;		EXECUTE STMT;		DEALLOCATE PREPARE STMT;		ELSE SELECT			CONCAT( "partition `", PARTITIONNAME, "` for table `", IN_SCHEMANAME, ".", IN_TABLENAME, "` already exists" ) AS result;			END IF;END //DELIMITER;												                            --手动测试call create_partition_by_month("ycdb", "t1");

3、数据库定时任务(每小时执行一次)

每小时执行一次，检查下个月的表分区是否已经创建，如果没有创建，则调用上面的存储过程创建。

DELIMITER $$#该表所在的数据库名称USE `ycdb`$$CREATE EVENT IF NOT EXISTS `Month_partition_t1`ON SCHEDULE EVERY 1 hour   #执行周期，还有天、月等等STARTS '2020-08-10 17:00:00'ON COMPLETION PRESERVEENABLECOMMENT 'Creating partitions By month'DO BEGIN    #调用刚才创建的存储过程，第一个参数是数据库名称，第二个参数是表名称    CALL ycdb.create_partition_by_month("ycdb", "t1");END$$DELIMITER ;

如果没有执行，请检查Mysql是否开启了event(默认是关闭的)

 [mysqld] event_scheduler=ON

后面会分享更多devops和DBA方面内容，感兴趣的朋友可以关注下~