mysql索引大小查询

Calculate index sizes

mysql> SELECT CONCAT(ROUND(SUM(index_length)/(1024*1024*1024), 2), ' GB') AS 'Total Index Size'
FROM information_schema.TABLES WHERE table_schema LIKE 'database';

+------------------+
| Total Index Size |
+------------------+
| 1.70 GB |
+------------------+
1 row in set (1.60 sec)

To calculate the total size of the data in the database

mysql> SELECT CONCAT(ROUND(SUM(data_length)/(1024*1024*1024), 2), ' GB') AS 'Total Data Size'
FROM information_schema.TABLES WHERE table_schema LIKE 'database';

+-----------------+
| Total Data Size |
+-----------------+
| 3.01 GB |
+-----------------+
1 row in set (1.35 sec)


An overall analysis of entire database on a per table basis

SELECT CONCAT(table_schema,'.',table_name) AS 'Table Name',
CONCAT(ROUND(table_rows/1000000,2),'M') AS 'Number of Rows',
CONCAT(ROUND(data_length/(1024*1024*1024),2),'G') AS 'Data Size',
CONCAT(ROUND(index_length/(1024*1024*1024),2),'G') AS 'Index Size' ,
CONCAT(ROUND((data_length+index_length)/(1024*1024*1024),2),'G')AS'Total'FROM information_schema.TABLES WHERE table_schema LIKE'database';

Just replace database with the partial name of your databaseyou need to analyze. Yes, I know, those wonderful Maatkit toolscontains mk-find which can do the same thing, but then you won't learnabout the information_schema database!!
MySQL DBA & Programming Blog by Mark Schoonover