查看mysql庫大小，表大小，索引大小

說明：

通過MySQL的 information_schema 數(shù)據(jù)庫，可查詢數(shù)據(jù)庫中每個表占用的空間、表記錄的行數(shù)；該庫中有一個 TABLES 表，這個表主要字段分別是：

TABLE_SCHEMA : 數(shù)據(jù)庫名
TABLE_NAME：表名
ENGINE：所使用的存儲引擎
TABLES_ROWS：記錄數(shù)
DATA_LENGTH：數(shù)據(jù)大小
INDEX_LENGTH：索引大小

其他字段請參考MySQL的手冊，查看一個表占用空間的大小，那就相當(dāng)于是 數(shù)據(jù)大小 + 索引大小 。

查看所有庫的大小

select concat(round(sum(DATA_LENGTH/1024/1024),2),'MB') as data  from TABLES; 
+----------+
| data     |
+----------+
| 104.21MB |
+----------+
1 row in set (0.11 sec)

查看指定庫的大小

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)</pre>

查看指定庫的指定表的大小

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)

查看指定庫的索引大小

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)

查看指定庫的指定表的索引大小

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)

show create table test.a_yuser
*************************** 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)

查看一個庫中的情況

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)