鲁达 概述
简单写了一个存储过程对mysql数据库中的表进行批量碎片清理，建议在业务空闲时间段进行。
思路
核心是利用mysql系统表和“optimize table 表名”命令，对mysql数据表进行空间的释放。由于delete和drop table都不会释放表空间（truncate 命令会释放表空间），所以需要利用optimize 命令进行释放。
这个存储过程目的是给一个库的所有表来整理碎片的。一个表随着插入很频繁，或者一直更新不停的，就会积累好多碎片。如果及时整理一下，查询效率会高出好多。
存储过程
整理如下：
DELIMITER $$ DROP PROCEDURE IF EXISTS `mysql`.`sp_optimize_tables`$$ CREATE PROCEDURE `mysql`.`sp_optimize_tables`( IN db_name varchar(255)) BEGIN -- To optimize all the tables in exact database. declare cnt int default 0; declare i int default 0; select count(*) as total from in where table_schema = db_name into cnt; while i < cnt do -- Get the table's exact name. set @stmt = concat('select table_name from in where table_schema = ''',db_name,''' order by table_name asc limit ',i,',1 into @tb_name'); prepare s1 from @stmt; execute s1; drop prepare s1; set @stmt = ''; set @stmt = concat('optimize table ',db_name,'.',@tb_name); prepare s1 from @stmt; execute s1; drop prepare s1; set @stmt = ''; set i = i + 1; end while; -- Refresh tables. flush tables; END$$ DELIMITER ;因为optimize有一些限定条件，所以也可以改成alter ... engine=innodb;这种方式。
DELIMITER $$ DROP PROCEDURE IF EXISTS `mysql`.`sp_optimize_tables2`$$ CREATE PROCEDURE `mysql`.`sp_optimize_tables2`( IN db_name varchar(255)) BEGIN -- To optimize all the tables in exact database. declare cnt int default 0; declare i int default 0; select count(*) as total from in where table_schema = db_name into cnt; while i < cnt do -- Get the table's exact name. set @stmt = concat('select table_name from in where table_schema = ''',db_name,''' order by table_name asc limit ',i,',1 into @tb_name'); prepare s1 from @stmt; execute s1; drop prepare s1; set @stmt = ''; set @stmt = concat('alter table ',db_name,'.',@tb_name,' engine=innodb'); prepare s1 from @stmt; execute s1; drop prepare s1; set @stmt = ''; set i = i + 1; end while; -- Refresh tables. flush tables; END$$ DELIMITER ;调用示例：
mysql> use mysql mysql> call sp_optimize_tables('database_name');因为我这表都是innodb，所以采用alter table XX engine=innodb方式。
mysql> use mysql mysql> call sp_optimize_tables2('database_name');觉得有用的朋友多帮忙转发哦！后面会分享更多devops和DBA方面的内容，感兴趣的朋友可以关注下~