Запрос для расчета размера таблиц начиная с MySQL 5.0:

use information_schema;
SELECT concat(table_schema,'.',table_name),concat(round(table_rows/1000000,2),'M') rows,
concat(round(data_length/(1024*1024*1024),2),'G') DATA,
concat(round(index_length/(1024*1024*1024),2),'G') idx,
concat(round((data_length+index_length)/(1024*1024*1024),2),'G') total_size,
round(index_length/data_length,2) idxfrac
FROM TABLES ORDER BY data_length+index_length DESC LIMIT 10;

| concat(table_schema,'.',table_name) | rows   | DATA   | idx    | total_size | idxfrac |
| art87.link_out87                    | 37.25M | 14.83G | 14.17G | 29.00G     |    0.96 |
#
| art87.article87                     | 12.67M | 15.83G | 4.79G  | 20.62G     |    0.30 |

URL: http://www.mysqlperformanceblog.com/2008/02/04/finding-out-l.../
Обсуждается: http://www.opennet.me/tips/info/1581.shtml

• Вычисление размера таблиц MySQL,Heckfy, 15:12 , 06-Фев-08

Думаю, так будет красивее:

use information_schema;
SELECT
concat(table_schema,'.',table_name) AS sql_table,
concat(round(table_rows/1000000,2),'M') rows,
concat(round(data_length/(1024*1024*1024),2),'G') DATA,
concat(round(index_length/(1024*1024*1024),2),'G') idx,
concat(round((data_length+index_length)/(1024*1024*1024),2),'G') total_size,
round(index_length/data_length,2) idxfrac
FROM TABLES
ORDER BY data_length+index_length DESC
LIMIT 10;

+------------------------+--------+--------+--------+------------+---------+
| sql_table              | rows   | DATA   | idx    | total_size | idxfrac |
+------------------------+--------+--------+--------+------------+---------+
| dev.event_logs_backup2 | 75.83M | 14.39G | 13.31G | 27.70G     |    0.93 |
| dev.event_logs_backup  | 26.90M | 4.48G  | 4.31G  | 8.79G      |    0.96 |
| dev.event_logs         | 1.20M  | 0.20G  | 0.14G  | 0.34G      |    0.69 |
| mysql.help_topic       | 0.00M  | 0.00G  | 0.00G  | 0.00G      |    0.05 |
| mysql.help_keyword     | 0.00M  | 0.00G  | 0.00G  | 0.00G      |    0.18 |
| mysql.proc             | 0.00M  | 0.00G  | 0.00G  | 0.00G      |    0.04 |
| mysql.help_category    | 0.00M  | 0.00G  | 0.00G  | 0.00G      |    0.15 |
| mysql.help_relation    | 0.00M  | 0.00G  | 0.00G  | 0.00G      |    2.11 |
+------------------------+--------+--------+--------+------------+---------+
10 rows in set (1.23 sec)