查看mysql库大小，表大小，索引大小

转自：http://www.cnblogs.com/lukcyjane/p/3849354.html

说明：

通过MySQL的 information_schema 数据库，可查询数据库中每个表占用的空间、表记录的行数；该库中有一个 TABLES 表，这个表主要字段分别是：

TABLE_SCHEMA : 数据库名
TABLE_NAME：表名
ENGINE：所使用的存储引擎
TABLES_ROWS：记录数
DATA_LENGTH：数据大小
INDEX_LENGTH：索引大小

其他字段请参考MySQL的手册，查看一个表占用空间的大小，那就相当于是 数据大小 + 索引大小 。

  查看所有库的大小

mysql> use information_schema;
Database changed
mysql> select concat(round(sum(DATA_LENGTH/1024/1024),2),"MB") as data  from TABLES;
+----------+
| data     |
+----------+
| 104.21MB |
+----------+
1 row in set (0.11 sec)

查看指定库的大小

mysql> select concat(round(sum(DATA_LENGTH/1024/1024),2),"MB") as data  from TABLES where table_schema="jishi";
+---------+
| data    |
+---------+
| 26.17MB |
+---------+
1 row in set (0.01 sec)

查看指定库的指定表的大小

mysql> select concat(round(sum(DATA_LENGTH/1024/1024),2),"MB") as data  from TABLES where table_schema="jishi" and table_name="a_ya";
+--------+
| data   |
+--------+
| 0.02MB |
+--------+
1 row in set (0.00 sec)

查看指定库的索引大小

mysql> SELECT CONCAT(ROUND(SUM(index_length)/(1024*1024), 2), " MB") AS "Total Index Size" FROM TABLES  WHERE table_schema = "jishi"; 
+------------------+
| Total Index Size |
+------------------+
| 0.94 MB          |
+------------------+
1 row in set (0.01 sec)

查看指定库的指定表的索引大小

mysql> SELECT CONCAT(ROUND(SUM(index_length)/(1024*1024), 2), " MB") AS "Total Index Size" FROM TABLES  WHERE table_schema = "test" and table_name="a_yuser"; 
+------------------+
| Total Index Size |
+------------------+
| 21.84 MB         |
+------------------+
1 row in set (0.00 sec)
mysql> show create table test.a_yuserG;
*************************** 1. row ***************************
       Table: a_yuser
Create Table: CREATE TABLE `a_yuser` (
  `email` varchar(60) NOT NULL DEFAULT "",
  `user_name` varchar(60) NOT NULL DEFAULT "",
  KEY `cc` (`email`(5)),
  KEY `ccb` (`user_name`(5)),
  KEY `ccbc` (`email`(5),`user_name`(5))
) ENGINE=MyISAM DEFAULT CHARSET=utf8
1 row in set (0.00 sec)
 
ERROR: 
No query specified
 
mysql> select count(*) from test.a_yuser;
+----------+
| count(*) |
+----------+
|  1073607 |
+----------+
1 row in set (0.00 sec)

查看一个库中的情况

mysql>  SELECT CONCAT(table_schema,".",table_name) AS "Table Name", CONCAT(ROUND(table_rows/1000000,4),"M") AS "Number of Rows", CONCAT(ROUND(data_length/(1024*1024*1024),4),"G") AS "Data Size", CONCAT(ROUND(index_length/(1024*1024*1024),4),"G") AS "Index Size", CONCAT(ROUND((data_length+index_length)/(1024*1024*1024),4),"G") AS"Total"FROM information_schema.TABLES WHERE table_schema LIKE "test";
+---------------+----------------+-----------+------------+---------+
| Table Name    | Number of Rows | Data Size | Index Size | Total   |
+---------------+----------------+-----------+------------+---------+
| test.a_br     | 0.4625M        | 0.0259G   | 0.0171G    | 0.0431G |
| test.a_skuclr | 0.7099M        | 0.0660G   | 0.0259G    | 0.0919G |
| test.a_yuser  | 1.0736M        | 0.0497G   | 0.0213G    | 0.0710G |
| test.test     | 0.0000M        | 0.0000G   | 0.0000G    | 0.0000G |
+---------------+----------------+-----------+------------+---------+
4 rows in set (0.13 sec)

参考网址：

http://www.oschina.net/question/12_3673 http://blog.sina.com.cn/s/blog_4c197d420101fbl9.html 好记性不如烂笔头，把遇到的问题及其解决方法记录下来。