本文收集于本人的笔记本,由于找不到原文出处。在此省略,如哪位知道可以联系我加上。
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【将所有的数据都删除】),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。
DELIMITER $$ DROP PROCEDURE IF EXISTS `mysql`.`sp_optimize_tables`$$ CREATE PROCEDURE `mysql`.`sp_optimize_tables`( IN db_name varchar(255)) BEGIN -- Created by david yeung 20080128. -- To optimize all the tables in exact database. declare cnt int default 0; declare i int default 0; select count(*) as total from information_schema.tables where table_schema = db_name into cnt; while i < cnt do -- Get the table's exact name. set @stmt = concat('select table_name from information_schema.tables 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 ;
调用示例:
mysql> use mysql
Database changed
mysql> call sp_optimize_tables('david_test');
+------------------------------+----------+----------+----------+
| Table | Op | Msg_type | Msg_text |
+------------------------------+----------+----------+----------+
| david_test.test1 | optimize | status | OK |
+------------------------------+----------+----------+----------+
1 row in set (0.26 sec)
+--------------------------+----------+----------+----------+
| Table | Op | Msg_type | Msg_text |
+--------------------------+----------+----------+----------+
| david_test.test2| optimize | status | OK |
+--------------------------+----------+----------+----------+
1 row in set (0.35 sec)
+---------------------------------------+----------+----------+----------+
| Table | Op | Msg_type | Msg_text |
+---------------------------------------+----------+----------+----------+
| david_test.test3 | optimize | status | OK |
+---------------------------------------+----------+----------+----------+
1 row in set (0.45 sec)
+--------------------------+----------+----------+----------+
| Table | Op | Msg_type | Msg_text |
+--------------------------+----------+----------+----------+
| david_test.test_article | optimize | status | OK |
+--------------------------+----------+----------+----------+
1 row in set (4.13 sec)
...
+----------------------------------+----------+----------+----------+
| Table | Op | Msg_type | Msg_text |
+----------------------------------+----------+----------+----------+
| david_test.test_article_content | optimize | status | OK |
+----------------------------------+----------+----------+----------+
1 row in set (37.81 sec)
+-----------------------+----------+----------+----------+
| Table | Op | Msg_type | Msg_text |
+-----------------------+----------+----------+----------+
| david_test.members | optimize | status | OK |
+-----------------------+----------+----------+----------+
1 row in set (40.02 sec)
+--------------------+----------+----------+----------+
| Table | Op | Msg_type | Msg_text |
+--------------------+----------+----------+----------+
| david_test.test_site | optimize | status | OK |
+--------------------+----------+----------+----------+
1 row in set (40.31 sec)
+--------------+----------+----------+----------+
| Table | Op | Msg_type | Msg_text |
+--------------+----------+----------+----------+
| david_test.t | optimize | status | OK |
+--------------+----------+----------+----------+
1 row in set (41.10 sec)
Query OK, 0 rows affected (41.13 sec)