How do I determine the size of an index in MySQL 5.1?

Question

How do I determine the size of an index in MySQL 5.1?

Answer 1

Use INFORMATION_SCHEMA.TABLES

Example : For a table called mydb.mytable, run this query

SELECT index_length NDXSIZE FROM INFORMATION_SCHEMA.TABLES
WHERE table_schema='mydb' AND table_name='mytable';

Answer comes back in bytes. If you want the answer in KB do this:

SELECT index_length/POWER(1024,1) NDXSIZE FROM INFORMATION_SCHEMA.TABLES
WHERE table_schema='mydb' AND table_name='mytable';

For MB, use POWER(1024,2)

For GB, use POWER(1024,3)

etc, etc, ...

Answer 2

is this what you need? (from here)