查看Mysql数据库数据量大小、表大小、索引大小

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
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TABLE_NAME：表名
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ENGINE：所使用的存储引擎
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TABLES_ROWS：记录数
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DATA_LENGTH：数据大小
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INDEX_LENGTH：索引大小
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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 。
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查看所有库的大小

mysql> use information_schema;
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Reading table information for completion of table and column names
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Database changed

mysql> select concat(round(sum(DATA_LENGTH/1024/1024),2),'MB') as data from TABLES;

+------------+

| data           |

+------------+

| 550.82MB |

+------------+

1 row in set (0.17 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='mysql';

+---------+

| data       |

+---------+

| 0.70MB |

+---------+

1 row in set (0.00 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='mysql' and table_name='user';

+---------+

| data       |

+---------+

| 0.00MB |

+---------+

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 = 'mysql';

+------------------+

| Total Index Size |

+------------------+

| 0.10 MB             |

+------------------+

1 row in set (0.00 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 = 'mysql' and table_name='user';

+------------------+

| Total Index Size |

+------------------+

| 0.00 MB             |

+------------------+

1 row in set (0.00 sec)

mysql> show create table mysql.user\G

*************************** 1. row ***************************

Table: user

Create Table: CREATE TABLE `user` (

`Host` char(60) COLLATE utf8_bin NOT NULL DEFAULT '',

`User` char(16) COLLATE utf8_bin NOT NULL DEFAULT '',

`Password` char(41) CHARACTER SET latin1 COLLATE latin1_bin NOT NULL DEFAULT '',

`Select_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Insert_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Update_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Delete_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Create_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Drop_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Reload_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Shutdown_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Process_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`File_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Grant_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`References_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Index_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Alter_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Show_db_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Super_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Create_tmp_table_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Lock_tables_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Execute_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Repl_slave_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Repl_client_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Create_view_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Show_view_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Create_routine_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Alter_routine_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Create_user_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Event_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Trigger_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Create_tablespace_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`ssl_type` enum('','ANY','X509','SPECIFIED') CHARACTER SET utf8 NOT NULL DEFAULT '',

`ssl_cipher` blob NOT NULL,

`x509_issuer` blob NOT NULL,

`x509_subject` blob NOT NULL,

`max_questions` int(11) unsigned NOT NULL DEFAULT '0',

`max_updates` int(11) unsigned NOT NULL DEFAULT '0',

`max_connections` int(11) unsigned NOT NULL DEFAULT '0',

`max_user_connections` int(11) unsigned NOT NULL DEFAULT '0',

`plugin` char(64) COLLATE utf8_bin DEFAULT 'mysql_native_password',

`authentication_string` text COLLATE utf8_bin,

`password_expired` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

PRIMARY KEY (`Host`,`User`)

) ENGINE=MyISAM DEFAULT CHARSET=utf8 COLLATE=utf8_bin COMMENT='Users and global privileges'

1 row in set (0.00 sec)

mysql> select count(*) from mysql.user;

+----------+

| count(*)  |

+----------+

| 20           |

+----------+

1 row in set (0.00 sec)

查询指定数据库中每个表的总行数,数据大小,索引大小和总大小

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 'mysql';

+---------------------------------+----------------+-----------+------------+---------+

| Table Name | Number of Rows | Data Size | Index Size | Total |

+---------------------------------+----------------+-----------+------------+---------+

| mysql.columns_priv                        | 0.0000M | 0.0000G | 0.0000G | 0.0000G |

| mysql.db                                          | 0.0001M | 0.0000G | 0.0000G | 0.0000G |

| mysql.event                                     | 0.0000M | 0.0000G | 0.0000G | 0.0000G |

| mysql.func                                       | 0.0000M | 0.0000G | 0.0000G | 0.0000G |

| mysql.general_log                           | 0.0000M | 0.0000G | 0.0000G | 0.0000G |

| mysql.help_category                       | 0.0000M | 0.0000G | 0.0000G | 0.0000G |

| mysql.help_keyword                       | 0.0006M | 0.0001G | 0.0000G | 0.0001G |

| mysql.help_relation                        | 0.0012M | 0.0000G | 0.0000G | 0.0000G |

| mysql.help_topic                             | 0.0006M | 0.0005G | 0.0000G | 0.0006G |

| mysql.ndb_binlog_index                 | 0.0000M | 0.0000G | 0.0000G | 0.0000G |

| mysql.plugin                                    | 0.0000M | 0.0000G | 0.0000G | 0.0000G |

| mysql.proc                                       | 0.0000M | 0.0000G | 0.0000G | 0.0000G |

| mysql.procs_priv                             | 0.0000M | 0.0000G | 0.0000G | 0.0000G |

| mysql.proxies_priv                          | 0.0000M | 0.0000G | 0.0000G | 0.0000G |

| mysql.servers                                  | 0.0000M | 0.0000G | 0.0000G | 0.0000G |

| mysql.slow_log                               | 0.0000M | 0.0000G | 0.0000G | 0.0000G |

| mysql.tables_priv                           | 0.0000M | 0.0000G | 0.0000G | 0.0000G |

| mysql.time_zone                            | 0.0000M | 0.0000G | 0.0000G | 0.0000G |

| mysql.time_zone_leap_second      | 0.0000M | 0.0000G | 0.0000G | 0.0000G |

| mysql.time_zone_name                 | 0.0000M | 0.0000G | 0.0000G | 0.0000G |

| mysql.time_zone_transition          | 0.0000M | 0.0000G | 0.0000G | 0.0000G |

| mysql.time_zone_transition_type | 0.0000M | 0.0000G | 0.0000G | 0.0000G |

| mysql.user                                      | 0.0000M | 0.0000G | 0.0000G | 0.0000G |

+---------------------------------+----------------+-----------+------------+---------+

23 rows in set (0.00 sec)

查询数据库指定表的数据部分大小,索引部分大小和总占用磁盘大小

mysql> SELECT

a.table_schema ,

a.table_name ,

concat(round(sum(DATA_LENGTH / 1024 / 1024) + sum(INDEX_LENGTH / 1024 / 1024) ,2) ,'MB') total_size ,

concat(round(sum(DATA_LENGTH / 1024 / 1024) , 2) ,'MB') AS data_size ,

concat(round(sum(INDEX_LENGTH / 1024 / 1024) , 2) ,'MB') AS index_size

FROM

information_schema. TABLES a

WHERE

a.table_schema = '数据库'

AND a.table_name = '表名';

+----------------+-------------+-----------+-----------+------------+

| table_schema | table_name | total_size | data_size | index_size |

+---------------+--------------+-----------+-----------+------------+

| mysql             | user              | 0.00MB    | 0.00MB    | 0.00MB    |

+---------------+---------------+-----------+-----------+-----------+

1 row in set (0.00 sec)